From 4a35731fb047a03e0cfbfb6a3ec6f31f54fac1c3 Mon Sep 17 00:00:00 2001
From: gregw <gregw@webtide.com>
Date: Mon, 26 Jun 2023 23:37:17 +0200
Subject: [PATCH 01/19] Experiment with a fully async
 ContentSourceCompletableFuture

For use by MultiPartFormData and MultiPartByteRanges
---
 .../jetty/http/MultiPartByteRanges.java       |  9 ++-
 .../eclipse/jetty/http/MultiPartFormData.java | 10 ++-
 .../ContentSourceCompletableFuture.java       | 80 +++++++++++++++++++
 .../servlet/ServletMultiPartFormData.java     |  3 +
 4 files changed, 100 insertions(+), 2 deletions(-)
 create mode 100644 jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/ContentSourceCompletableFuture.java

diff --git a/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartByteRanges.java b/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartByteRanges.java
index 944d9f1dee54..57c89a18bb48 100644
--- a/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartByteRanges.java
+++ b/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartByteRanges.java
@@ -13,6 +13,7 @@
 
 package org.eclipse.jetty.http;
 
+import java.io.EOFException;
 import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.nio.channels.SeekableByteChannel;
@@ -54,6 +55,7 @@
  */
 public class MultiPartByteRanges extends CompletableFuture<MultiPartByteRanges.Parts>
 {
+    // TODO base the implementation on a ContentSourceCompletableFuture
     private final PartsListener listener = new PartsListener();
     private final MultiPart.Parser parser;
 
@@ -108,8 +110,13 @@ public void run()
                     }
                     parse(chunk);
                     chunk.release();
-                    if (chunk.isLast() || isDone())
+                    if (isDone())
                         return;
+                    if (chunk.isLast())
+                    {
+                        listener.onFailure(new EOFException());
+                        return;
+                    }
                 }
             }
         }.run();
diff --git a/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartFormData.java b/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartFormData.java
index 851e4c085510..f9556b59ed63 100644
--- a/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartFormData.java
+++ b/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartFormData.java
@@ -14,6 +14,7 @@
 package org.eclipse.jetty.http;
 
 import java.io.Closeable;
+import java.io.EOFException;
 import java.nio.ByteBuffer;
 import java.nio.channels.NonWritableChannelException;
 import java.nio.channels.SeekableByteChannel;
@@ -69,6 +70,8 @@
  */
 public class MultiPartFormData extends CompletableFuture<MultiPartFormData.Parts>
 {
+    // TODO base the implementation on a ContentSourceCompletableFuture
+
     private static final Logger LOG = LoggerFactory.getLogger(MultiPartFormData.class);
 
     private final PartsListener listener = new PartsListener();
@@ -124,8 +127,13 @@ public void run()
                     }
                     parse(chunk);
                     chunk.release();
-                    if (chunk.isLast() || isDone())
+                    if (isDone())
+                        return;
+                    if (chunk.isLast())
+                    {
+                        listener.onFailure(new EOFException());
                         return;
+                    }
                 }
             }
         }.run();
diff --git a/jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/ContentSourceCompletableFuture.java b/jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/ContentSourceCompletableFuture.java
new file mode 100644
index 000000000000..3fa4e7061a73
--- /dev/null
+++ b/jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/ContentSourceCompletableFuture.java
@@ -0,0 +1,80 @@
+//
+// ========================================================================
+// Copyright (c) 1995 Mort Bay Consulting Pty Ltd and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
+// which is available at https://www.apache.org/licenses/LICENSE-2.0.
+//
+// SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
+// ========================================================================
+//
+
+package org.eclipse.jetty.io.content;
+
+import java.io.EOFException;
+import java.util.concurrent.CompletableFuture;
+
+import org.eclipse.jetty.io.Content;
+
+/**
+ *
+ */
+public abstract class ContentSourceCompletableFuture<X> extends CompletableFuture<X>
+{
+    private final Content.Source _content;
+
+    public ContentSourceCompletableFuture(Content.Source content)
+    {
+        _content = content;
+    }
+
+    public boolean parse()
+    {
+        onContentAvailable();
+        return isDone();
+    }
+
+    private void onContentAvailable()
+    {
+        while (true)
+        {
+            Content.Chunk chunk = _content.read();
+            if (chunk == null)
+            {
+                _content.demand(this::onContentAvailable);
+                return;
+            }
+            if (Content.Chunk.isFailure(chunk))
+            {
+                if (!chunk.isLast() && ignoreTransientFailure(chunk.getFailure()))
+                    continue;
+                completeExceptionally(chunk.getFailure());
+                return;
+            }
+
+            X x = parse(chunk);
+            chunk.release();
+
+            if (x != null)
+            {
+                complete(x);
+                return;
+            }
+            if (chunk.isLast())
+            {
+                completeExceptionally(new EOFException());
+                return;
+            }
+        }
+    }
+
+    protected abstract X parse(Content.Chunk chunk);
+
+    protected boolean ignoreTransientFailure(Throwable cause)
+    {
+        return false;
+    }
+}
+
diff --git a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletMultiPartFormData.java b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletMultiPartFormData.java
index 3ea59caec4a8..fb04400c95b1 100644
--- a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletMultiPartFormData.java
+++ b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletMultiPartFormData.java
@@ -102,6 +102,9 @@ private Parts parse(ServletApiRequest request, int maxParts) throws IOException
             throw new IllegalStateException("No multipart boundary parameter in Content-Type");
 
         // Store MultiPartFormData as attribute on request so it is released by the HttpChannel.
+        // TODO we should look for an already done MultiPartFormData as an attribute, so it can be
+        //      read asynchronously without blocking by something like the DelayedHandler (although
+        //      probably need an in ServletContext variant to get the configuration below.
         MultiPartFormData formData = new MultiPartFormData(boundary);
         formData.setMaxParts(maxParts);
 

From 86a08c55a821447ea09600966b15246b2f1484d0 Mon Sep 17 00:00:00 2001
From: gregw <gregw@webtide.com>
Date: Tue, 27 Jun 2023 10:37:30 +0200
Subject: [PATCH 02/19] Experiment with a fully async
 ContentSourceCompletableFuture

WIP
---
 .../eclipse/jetty/http/MultiPartFormData.java |  70 ++-----
 .../jetty/http/MultiPartFormDataTest.java     | 189 +++++++++++-------
 .../jetty/io/content/AsyncContent.java        |   2 +-
 .../ContentSourceCompletableFuture.java       |  25 ++-
 .../handler/MultiPartFormDataHandlerTest.java |   9 +-
 .../servlet/ServletMultiPartFormData.java     |  41 +---
 6 files changed, 163 insertions(+), 173 deletions(-)

diff --git a/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartFormData.java b/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartFormData.java
index f9556b59ed63..499507865f80 100644
--- a/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartFormData.java
+++ b/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartFormData.java
@@ -14,7 +14,6 @@
 package org.eclipse.jetty.http;
 
 import java.io.Closeable;
-import java.io.EOFException;
 import java.nio.ByteBuffer;
 import java.nio.channels.NonWritableChannelException;
 import java.nio.channels.SeekableByteChannel;
@@ -29,6 +28,7 @@
 import java.util.concurrent.CompletableFuture;
 
 import org.eclipse.jetty.io.Content;
+import org.eclipse.jetty.io.content.ContentSourceCompletableFuture;
 import org.eclipse.jetty.util.IO;
 import org.eclipse.jetty.util.thread.AutoLock;
 import org.slf4j.Logger;
@@ -38,8 +38,7 @@
 
 /**
  * <p>A {@link CompletableFuture} that is completed when a multipart/form-data content
- * has been parsed asynchronously from a {@link Content.Source} via {@link #parse(Content.Source)}
- * or from one or more {@link Content.Chunk}s via {@link #parse(Content.Chunk)}.</p>
+ * has been parsed asynchronously from a {@link Content.Source}.</p>
  * <p>Once the parsing of the multipart/form-data content completes successfully,
  * objects of this class are completed with a {@link Parts} object.</p>
  * <p>Objects of this class may be configured to save multipart files in a configurable
@@ -68,7 +67,7 @@
  *
  * @see Parts
  */
-public class MultiPartFormData extends CompletableFuture<MultiPartFormData.Parts>
+public class MultiPartFormData extends ContentSourceCompletableFuture<MultiPartFormData.Parts>
 {
     // TODO base the implementation on a ContentSourceCompletableFuture
 
@@ -82,9 +81,11 @@ public class MultiPartFormData extends CompletableFuture<MultiPartFormData.Parts
     private long maxMemoryFileSize;
     private long maxLength = -1;
     private long length;
+    private Parts parts;
 
-    public MultiPartFormData(String boundary)
+    public MultiPartFormData(Content.Source source, String boundary)
     {
+        super(source);
         parser = new MultiPart.Parser(Objects.requireNonNull(boundary), listener);
     }
 
@@ -96,50 +97,6 @@ public String getBoundary()
         return parser.getBoundary();
     }
 
-    /**
-     * <p>Parses the given multipart/form-data content.</p>
-     * <p>Returns this {@code MultiPartFormData} object,
-     * so that it can be used in the typical "fluent"
-     * style of {@link CompletableFuture}.</p>
-     *
-     * @param content the multipart/form-data content to parse
-     * @return this {@code MultiPartFormData} object
-     */
-    public MultiPartFormData parse(Content.Source content)
-    {
-        new Runnable()
-        {
-            @Override
-            public void run()
-            {
-                while (true)
-                {
-                    Content.Chunk chunk = content.read();
-                    if (chunk == null)
-                    {
-                        content.demand(this);
-                        return;
-                    }
-                    if (Content.Chunk.isFailure(chunk))
-                    {
-                        listener.onFailure(chunk.getFailure());
-                        return;
-                    }
-                    parse(chunk);
-                    chunk.release();
-                    if (isDone())
-                        return;
-                    if (chunk.isLast())
-                    {
-                        listener.onFailure(new EOFException());
-                        return;
-                    }
-                }
-            }
-        }.run();
-        return this;
-    }
-
     /**
      * <p>Parses the given chunk containing multipart/form-data bytes.</p>
      * <p>One or more chunks may be passed to this method, until the parsing
@@ -147,16 +104,17 @@ public void run()
      *
      * @param chunk the {@link Content.Chunk} to parse.
      */
-    public void parse(Content.Chunk chunk)
+    @Override
+    protected MultiPartFormData.Parts parse(Content.Chunk chunk)
     {
         if (listener.isFailed())
-            return;
+            return null;
         length += chunk.getByteBuffer().remaining();
         long max = getMaxLength();
         if (max > 0 && length > max)
-            listener.onFailure(new IllegalStateException("max length exceeded: %d".formatted(max)));
-        else
-            parser.parse(chunk);
+            throw new IllegalStateException("max length exceeded: %d".formatted(max));
+        parser.parse(chunk);
+        return parts;
     }
 
     /**
@@ -550,8 +508,8 @@ public void onComplete()
             try (AutoLock ignored = lock.lock())
             {
                 result = List.copyOf(parts);
+                MultiPartFormData.this.parts = new Parts(result);
             }
-            complete(new Parts(result));
         }
 
         Charset getDefaultCharset()
@@ -579,7 +537,7 @@ int getPartsSize()
         public void onFailure(Throwable failure)
         {
             super.onFailure(failure);
-            completeExceptionally(failure);
+            completeExceptionally(failure); // TODO not here
         }
 
         private void fail(Throwable cause)
diff --git a/jetty-core/jetty-http/src/test/java/org/eclipse/jetty/http/MultiPartFormDataTest.java b/jetty-core/jetty-http/src/test/java/org/eclipse/jetty/http/MultiPartFormDataTest.java
index a1f771f1ca28..3fa1ffa2ec07 100644
--- a/jetty-core/jetty-http/src/test/java/org/eclipse/jetty/http/MultiPartFormDataTest.java
+++ b/jetty-core/jetty-http/src/test/java/org/eclipse/jetty/http/MultiPartFormDataTest.java
@@ -16,7 +16,6 @@
 import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.nio.charset.Charset;
-import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.ArrayList;
@@ -26,9 +25,10 @@
 import java.util.concurrent.atomic.AtomicInteger;
 
 import org.eclipse.jetty.io.Content;
+import org.eclipse.jetty.io.content.AsyncContent;
 import org.eclipse.jetty.toolchain.test.FS;
 import org.eclipse.jetty.toolchain.test.MavenTestingUtils;
-import org.eclipse.jetty.util.BufferUtil;
+import org.eclipse.jetty.util.Callback;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Disabled;
@@ -71,32 +71,19 @@ public void dispose()
         int leaks = 0;
         for (Content.Chunk chunk : _allocatedChunks)
         {
-            // Any release that does not return true is a leak.
-            if (!chunk.release())
-                leaks++;
+            // Any release that does not throw or return true is a leak.
+            try
+            {
+                if (!chunk.release())
+                    leaks++;
+            }
+            catch (IllegalStateException ignored)
+            {
+            }
         }
         assertThat("Leaked " + leaks + "/" + _allocatedChunks.size() + " chunk(s)", leaks, is(0));
     }
 
-    Content.Chunk asChunk(String data, boolean last)
-    {
-        byte[] b = data.getBytes(StandardCharsets.UTF_8);
-        ByteBuffer buffer = BufferUtil.allocate(b.length);
-        BufferUtil.append(buffer, b);
-        Content.Chunk chunk = Content.Chunk.from(buffer, last);
-        _allocatedChunks.add(chunk);
-        return chunk;
-    }
-
-    Content.Chunk asChunk(ByteBuffer data, boolean last)
-    {
-        ByteBuffer buffer = BufferUtil.allocate(data.remaining());
-        BufferUtil.append(buffer, data);
-        Content.Chunk chunk = Content.Chunk.from(buffer, last);
-        _allocatedChunks.add(chunk);
-        return chunk;
-    }
-
     @Test
     public void testBadMultiPart() throws Exception
     {
@@ -109,12 +96,14 @@ public void testBadMultiPart() throws Exception
             "Content-Disposition: form-data; name=\"fileup\"; filename=\"test.upload\"\r\n" +
             "\r\n";
 
-        MultiPartFormData formData = new MultiPartFormData(boundary);
+        AsyncContent source = new TestContent();
+        MultiPartFormData formData = new MultiPartFormData(source, boundary);
         formData.setFilesDirectory(_tmpDir);
         formData.setMaxFileSize(1024);
         formData.setMaxLength(3072);
         formData.setMaxMemoryFileSize(50);
-        formData.parse(asChunk(str, true));
+        Content.Sink.write(source, true, str, Callback.NOOP);
+        formData.parse();
 
         formData.handle((parts, failure) ->
         {
@@ -139,12 +128,14 @@ public void testFinalBoundaryOnly() throws Exception
             eol +
             "--" + boundary + "--" + eol;
 
-        MultiPartFormData formData = new MultiPartFormData(boundary);
+        AsyncContent source = new TestContent();
+        MultiPartFormData formData = new MultiPartFormData(source, boundary);
         formData.setFilesDirectory(_tmpDir);
         formData.setMaxFileSize(1024);
         formData.setMaxLength(3072);
         formData.setMaxMemoryFileSize(50);
-        formData.parse(asChunk(str, true));
+        Content.Sink.write(source, true, str, Callback.NOOP);
+        formData.parse();
 
         formData.whenComplete((parts, failure) ->
         {
@@ -165,12 +156,14 @@ public void testEmpty() throws Exception
         String str = eol +
             "--" + boundary + "--" + eol;
 
-        MultiPartFormData formData = new MultiPartFormData(boundary);
+        AsyncContent source = new TestContent();
+        MultiPartFormData formData = new MultiPartFormData(source, boundary);
         formData.setFilesDirectory(_tmpDir);
         formData.setMaxFileSize(1024);
         formData.setMaxLength(3072);
         formData.setMaxMemoryFileSize(50);
-        formData.parse(asChunk(str, true));
+        Content.Sink.write(source, true, str, Callback.NOOP);
+        formData.parse();
 
         formData.whenComplete((parts, failure) ->
         {
@@ -213,12 +206,14 @@ public void testEmptyStringBoundary() throws Exception
             ----\r
             """;
 
-        MultiPartFormData formData = new MultiPartFormData("");
+        AsyncContent source = new TestContent();
+        MultiPartFormData formData = new MultiPartFormData(source, "");
         formData.setFilesDirectory(_tmpDir);
         formData.setMaxFileSize(1024);
         formData.setMaxLength(3072);
         formData.setMaxMemoryFileSize(50);
-        formData.parse(asChunk(str, true));
+        Content.Sink.write(source, true, str, Callback.NOOP);
+        formData.parse();
 
         try (MultiPartFormData.Parts parts = formData.get(5, TimeUnit.SECONDS))
         {
@@ -253,8 +248,10 @@ public void testEmptyStringBoundary() throws Exception
     @Test
     public void testNoBody() throws Exception
     {
-        MultiPartFormData formData = new MultiPartFormData("boundary");
-        formData.parse(Content.Chunk.EOF);
+        AsyncContent source = new TestContent();
+        MultiPartFormData formData = new MultiPartFormData(source, "boundary");
+        source.close();
+        formData.parse();
 
         formData.handle((parts, failure) ->
         {
@@ -268,9 +265,11 @@ public void testNoBody() throws Exception
     @Test
     public void testBodyWithOnlyCRLF() throws Exception
     {
-        MultiPartFormData formData = new MultiPartFormData("boundary");
+        AsyncContent source = new TestContent();
+        MultiPartFormData formData = new MultiPartFormData(source, "boundary");
         String body = "              \n\n\n\r\n\r\n\r\n\r\n";
-        formData.parse(asChunk(body, true));
+        Content.Sink.write(source, true, body, Callback.NOOP);
+        formData.parse();
 
         formData.handle((parts, failure) ->
         {
@@ -285,7 +284,7 @@ public void testBodyWithOnlyCRLF() throws Exception
     public void testLeadingWhitespaceBodyWithCRLF() throws Exception
     {
         String body = """
-            
+                        
 
             \r
             \r
@@ -303,12 +302,14 @@ public void testLeadingWhitespaceBodyWithCRLF() throws Exception
             --AaB03x--\r
             """;
 
-        MultiPartFormData formData = new MultiPartFormData("AaB03x");
+        AsyncContent source = new TestContent();
+        MultiPartFormData formData = new MultiPartFormData(source, "AaB03x");
         formData.setFilesDirectory(_tmpDir);
         formData.setMaxFileSize(1024);
         formData.setMaxLength(3072);
         formData.setMaxMemoryFileSize(50);
-        formData.parse(asChunk(body, true));
+        Content.Sink.write(source, true, body, Callback.NOOP);
+        formData.parse();
 
         try (MultiPartFormData.Parts parts = formData.get(5, TimeUnit.SECONDS))
         {
@@ -340,12 +341,14 @@ public void testLeadingWhitespaceBodyWithoutCRLF() throws Exception
             --AaB03x--\r
             """;
 
-        MultiPartFormData formData = new MultiPartFormData("AaB03x");
+        AsyncContent source = new TestContent();
+        MultiPartFormData formData = new MultiPartFormData(source, "AaB03x");
         formData.setFilesDirectory(_tmpDir);
         formData.setMaxFileSize(1024);
         formData.setMaxLength(3072);
         formData.setMaxMemoryFileSize(50);
-        formData.parse(asChunk(body, true));
+        Content.Sink.write(source, true, body, Callback.NOOP);
+        formData.parse();
 
         try (MultiPartFormData.Parts parts = formData.get(5, TimeUnit.SECONDS))
         {
@@ -361,7 +364,8 @@ public void testLeadingWhitespaceBodyWithoutCRLF() throws Exception
     @Test
     public void testDefaultLimits() throws Exception
     {
-        MultiPartFormData formData = new MultiPartFormData("AaB03x");
+        AsyncContent source = new TestContent();
+        MultiPartFormData formData = new MultiPartFormData(source, "AaB03x");
         formData.setFilesDirectory(_tmpDir);
         String body = """
             --AaB03x\r
@@ -371,7 +375,8 @@ public void testDefaultLimits() throws Exception
             ABCDEFGHIJKLMNOPQRSTUVWXYZ\r
             --AaB03x--\r
             """;
-        formData.parse(asChunk(body, true));
+        Content.Sink.write(source, true, body, Callback.NOOP);
+        formData.parse();
 
         try (MultiPartFormData.Parts parts = formData.get(5, TimeUnit.SECONDS))
         {
@@ -390,7 +395,8 @@ public void testDefaultLimits() throws Exception
     @Test
     public void testRequestContentTooBig() throws Exception
     {
-        MultiPartFormData formData = new MultiPartFormData("AaB03x");
+        AsyncContent source = new TestContent();
+        MultiPartFormData formData = new MultiPartFormData(source, "AaB03x");
         formData.setFilesDirectory(_tmpDir);
         formData.setMaxLength(16);
 
@@ -402,7 +408,8 @@ public void testRequestContentTooBig() throws Exception
             ABCDEFGHIJKLMNOPQRSTUVWXYZ\r
             --AaB03x--\r
             """;
-        formData.parse(asChunk(body, true));
+        Content.Sink.write(source, true, body, Callback.NOOP);
+        formData.parse();
 
         formData.handle((parts, failure) ->
         {
@@ -416,7 +423,8 @@ public void testRequestContentTooBig() throws Exception
     @Test
     public void testFileTooBig() throws Exception
     {
-        MultiPartFormData formData = new MultiPartFormData("AaB03x");
+        AsyncContent source = new TestContent();
+        MultiPartFormData formData = new MultiPartFormData(source, "AaB03x");
         formData.setFilesDirectory(_tmpDir);
         formData.setMaxFileSize(16);
 
@@ -428,7 +436,8 @@ public void testFileTooBig() throws Exception
             ABCDEFGHIJKLMNOPQRSTUVWXYZ\r
             --AaB03x--\r
             """;
-        formData.parse(asChunk(body, true));
+        Content.Sink.write(source, true, body, Callback.NOOP);
+        formData.parse();
 
         formData.handle((parts, failure) ->
         {
@@ -442,7 +451,8 @@ public void testFileTooBig() throws Exception
     @Test
     public void testTwoFilesOneInMemoryOneOnDisk() throws Exception
     {
-        MultiPartFormData formData = new MultiPartFormData("AaB03x");
+        AsyncContent source = new TestContent();
+        MultiPartFormData formData = new MultiPartFormData(source, "AaB03x");
         formData.setFilesDirectory(_tmpDir);
         String chunk = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
         formData.setMaxMemoryFileSize(chunk.length() + 1);
@@ -460,7 +470,8 @@ public void testTwoFilesOneInMemoryOneOnDisk() throws Exception
             $C$C$C$C\r
             --AaB03x--\r
             """.replace("$C", chunk);
-        formData.parse(asChunk(body, true));
+        Content.Sink.write(source, true, body, Callback.NOOP);
+        formData.parse();
 
         try (MultiPartFormData.Parts parts = formData.get(5, TimeUnit.SECONDS))
         {
@@ -482,7 +493,8 @@ public void testTwoFilesOneInMemoryOneOnDisk() throws Exception
     @Test
     public void testPartWrite() throws Exception
     {
-        MultiPartFormData formData = new MultiPartFormData("AaB03x");
+        AsyncContent source = new TestContent();
+        MultiPartFormData formData = new MultiPartFormData(source, "AaB03x");
         formData.setFilesDirectory(_tmpDir);
         String chunk = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
         formData.setMaxMemoryFileSize(chunk.length() + 1);
@@ -500,7 +512,8 @@ public void testPartWrite() throws Exception
             $C$C$C$C\r
             --AaB03x--\r
             """.replace("$C", chunk);
-        formData.parse(asChunk(body, true));
+        Content.Sink.write(source, true, body, Callback.NOOP);
+        formData.parse();
 
         try (MultiPartFormData.Parts parts = formData.get(5, TimeUnit.SECONDS))
         {
@@ -528,7 +541,8 @@ public void testPartWrite() throws Exception
     @Test
     public void testPathPartDelete() throws Exception
     {
-        MultiPartFormData formData = new MultiPartFormData("AaB03x");
+        AsyncContent source = new TestContent();
+        MultiPartFormData formData = new MultiPartFormData(source, "AaB03x");
         formData.setFilesDirectory(_tmpDir);
 
         String body = """
@@ -539,7 +553,8 @@ public void testPathPartDelete() throws Exception
             ABCDEFGHIJKLMNOPQRSTUVWXYZ\r
             --AaB03x--\r
             """;
-        formData.parse(asChunk(body, true));
+        Content.Sink.write(source, true, body, Callback.NOOP);
+        formData.parse();
 
         try (MultiPartFormData.Parts parts = formData.get(5, TimeUnit.SECONDS))
         {
@@ -559,7 +574,8 @@ public void testPathPartDelete() throws Exception
     @Test
     public void testAbort()
     {
-        MultiPartFormData formData = new MultiPartFormData("AaB03x");
+        AsyncContent source = new TestContent();
+        MultiPartFormData formData = new MultiPartFormData(source, "AaB03x");
         formData.setFilesDirectory(_tmpDir);
         formData.setMaxMemoryFileSize(32);
 
@@ -575,14 +591,15 @@ public void testAbort()
             --AaB03x--\r
             """;
         // Parse only part of the content.
-        formData.parse(asChunk(body, false));
+        Content.Sink.write(source, false, body, Callback.NOOP);
+        formData.parse();
         assertEquals(1, formData.getPartsSize());
 
         // Abort MultiPartFormData.
         formData.completeExceptionally(new IOException());
 
         // Parse the rest of the content.
-        formData.parse(asChunk(terminator, true));
+        Content.Sink.write(source, true, terminator, Callback.NOOP);
 
         // Try to get the parts, it should fail.
         assertThrows(ExecutionException.class, () -> formData.get(5, TimeUnit.SECONDS));
@@ -592,7 +609,8 @@ public void testAbort()
     @Test
     public void testMaxHeaderLength() throws Exception
     {
-        MultiPartFormData formData = new MultiPartFormData("AaB03x");
+        AsyncContent source = new TestContent();
+        MultiPartFormData formData = new MultiPartFormData(source, "AaB03x");
         formData.setFilesDirectory(_tmpDir);
         formData.setPartHeadersMaxLength(32);
 
@@ -604,7 +622,8 @@ public void testMaxHeaderLength() throws Exception
             ABCDEFGHIJKLMNOPQRSTUVWXYZ\r
             --AaB03x--\r
             """;
-        formData.parse(asChunk(body, true));
+        formData.parse();
+        Content.Sink.write(source, true, body, Callback.NOOP);
 
         formData.handle((parts, failure) ->
         {
@@ -618,7 +637,8 @@ public void testMaxHeaderLength() throws Exception
     @Test
     public void testDefaultCharset() throws Exception
     {
-        MultiPartFormData formData = new MultiPartFormData("AaB03x");
+        AsyncContent source = new TestContent();
+        MultiPartFormData formData = new MultiPartFormData(source, "AaB03x");
         formData.setFilesDirectory(_tmpDir);
         formData.setMaxMemoryFileSize(-1);
 
@@ -645,11 +665,12 @@ public void testDefaultCharset() throws Exception
             \r
             --AaB03x--\r
             """;
-        formData.parse(asChunk(body1, false));
-        formData.parse(asChunk(isoCedilla, false));
-        formData.parse(asChunk(body2, false));
-        formData.parse(asChunk(utfCedilla, false));
-        formData.parse(asChunk(terminator, true));
+        formData.parse();
+        Content.Sink.write(source, false, body1, Callback.NOOP);
+        source.write(false, isoCedilla, Callback.NOOP);
+        Content.Sink.write(source, false, body2, Callback.NOOP);
+        source.write(false, utfCedilla, Callback.NOOP);
+        Content.Sink.write(source, true, terminator, Callback.NOOP);
 
         try (MultiPartFormData.Parts parts = formData.get(5, TimeUnit.SECONDS))
         {
@@ -669,7 +690,8 @@ public void testDefaultCharset() throws Exception
     @Test
     public void testPartWithBackSlashInFileName() throws Exception
     {
-        MultiPartFormData formData = new MultiPartFormData("AaB03x");
+        AsyncContent source = new TestContent();
+        MultiPartFormData formData = new MultiPartFormData(source, "AaB03x");
         formData.setFilesDirectory(_tmpDir);
         formData.setMaxMemoryFileSize(-1);
 
@@ -681,7 +703,8 @@ public void testPartWithBackSlashInFileName() throws Exception
             stuffaaa\r
             --AaB03x--\r
             """;
-        formData.parse(asChunk(contents, true));
+        formData.parse();
+        Content.Sink.write(source, true, contents, Callback.NOOP);
 
         try (MultiPartFormData.Parts parts = formData.get(5, TimeUnit.SECONDS))
         {
@@ -694,7 +717,8 @@ public void testPartWithBackSlashInFileName() throws Exception
     @Test
     public void testPartWithWindowsFileName() throws Exception
     {
-        MultiPartFormData formData = new MultiPartFormData("AaB03x");
+        AsyncContent source = new TestContent();
+        MultiPartFormData formData = new MultiPartFormData(source, "AaB03x");
         formData.setFilesDirectory(_tmpDir);
         formData.setMaxMemoryFileSize(-1);
 
@@ -706,7 +730,8 @@ public void testPartWithWindowsFileName() throws Exception
             stuffaaa\r
             --AaB03x--\r
             """;
-        formData.parse(asChunk(contents, true));
+        Content.Sink.write(source, true, contents, Callback.NOOP);
+        formData.parse();
 
         try (MultiPartFormData.Parts parts = formData.get(5, TimeUnit.SECONDS))
         {
@@ -722,7 +747,8 @@ public void testPartWithWindowsFileName() throws Exception
     @Disabled
     public void testCorrectlyEncodedMSFilename() throws Exception
     {
-        MultiPartFormData formData = new MultiPartFormData("AaB03x");
+        AsyncContent source = new TestContent();
+        MultiPartFormData formData = new MultiPartFormData(source, "AaB03x");
         formData.setFilesDirectory(_tmpDir);
         formData.setMaxMemoryFileSize(-1);
 
@@ -734,7 +760,8 @@ public void testCorrectlyEncodedMSFilename() throws Exception
             stuffaaa\r
             --AaB03x--\r
             """;
-        formData.parse(asChunk(contents, true));
+        Content.Sink.write(source, true, contents, Callback.NOOP);
+        formData.parse();
 
         try (MultiPartFormData.Parts parts = formData.get(5, TimeUnit.SECONDS))
         {
@@ -747,7 +774,8 @@ public void testCorrectlyEncodedMSFilename() throws Exception
     @Test
     public void testWriteFilesForPartWithoutFileName() throws Exception
     {
-        MultiPartFormData formData = new MultiPartFormData("AaB03x");
+        AsyncContent source = new TestContent();
+        MultiPartFormData formData = new MultiPartFormData(source, "AaB03x");
         formData.setFilesDirectory(_tmpDir);
         formData.setUseFilesForPartsWithoutFileName(true);
 
@@ -759,7 +787,8 @@ public void testWriteFilesForPartWithoutFileName() throws Exception
             sssaaa\r
             --AaB03x--\r
             """;
-        formData.parse(asChunk(body, true));
+        Content.Sink.write(source, true, body, Callback.NOOP);
+        formData.parse();
 
         try (MultiPartFormData.Parts parts = formData.get(5, TimeUnit.SECONDS))
         {
@@ -775,7 +804,8 @@ public void testWriteFilesForPartWithoutFileName() throws Exception
     @Test
     public void testPartsWithSameName() throws Exception
     {
-        MultiPartFormData formData = new MultiPartFormData("AaB03x");
+        AsyncContent source = new TestContent();
+        MultiPartFormData formData = new MultiPartFormData(source, "AaB03x");
         formData.setFilesDirectory(_tmpDir);
 
         String sameNames = """
@@ -791,7 +821,8 @@ public void testPartsWithSameName() throws Exception
             AAAAA\r
             --AaB03x--\r
             """;
-        formData.parse(asChunk(sameNames, true));
+        Content.Sink.write(source, true, sameNames, Callback.NOOP);
+        formData.parse();
 
         try (MultiPartFormData.Parts parts = formData.get(5, TimeUnit.SECONDS))
         {
@@ -810,4 +841,14 @@ public void testPartsWithSameName() throws Exception
             assertEquals("AAAAA", part2.getContentAsString(formData.getDefaultCharset()));
         }
     }
+
+    private class TestContent extends AsyncContent
+    {
+        @Override
+        protected void offer(Content.Chunk chunk)
+        {
+            _allocatedChunks.add(chunk);
+            super.offer(chunk);
+        }
+    }
 }
diff --git a/jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/AsyncContent.java b/jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/AsyncContent.java
index 6bd5eeebc32a..9ab80e4282cf 100644
--- a/jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/AsyncContent.java
+++ b/jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/AsyncContent.java
@@ -79,7 +79,7 @@ public void write(boolean last, ByteBuffer byteBuffer, Callback callback)
      * or succeeded if and only if the chunk is terminal, as non-terminal
      * chunks have to bind the succeeding of the callback to their release.
      */
-    private void offer(Content.Chunk chunk)
+    protected void offer(Content.Chunk chunk)
     {
         Throwable failure = null;
         boolean wasEmpty = false;
diff --git a/jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/ContentSourceCompletableFuture.java b/jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/ContentSourceCompletableFuture.java
index 3fa4e7061a73..55c91c282cd9 100644
--- a/jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/ContentSourceCompletableFuture.java
+++ b/jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/ContentSourceCompletableFuture.java
@@ -30,10 +30,10 @@ public ContentSourceCompletableFuture(Content.Source content)
         _content = content;
     }
 
-    public boolean parse()
+    public CompletableFuture<X> parse()
     {
         onContentAvailable();
-        return isDone();
+        return this;
     }
 
     private void onContentAvailable()
@@ -54,14 +54,25 @@ private void onContentAvailable()
                 return;
             }
 
-            X x = parse(chunk);
-            chunk.release();
-
-            if (x != null)
+            try
+            {
+                X x = parse(chunk);
+                if (x != null)
+                {
+                    complete(x);
+                    return;
+                }
+            }
+            catch (Throwable failure)
             {
-                complete(x);
+                completeExceptionally(failure);
                 return;
             }
+            finally
+            {
+                chunk.release();
+            }
+
             if (chunk.isLast())
             {
                 completeExceptionally(new EOFException());
diff --git a/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/handler/MultiPartFormDataHandlerTest.java b/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/handler/MultiPartFormDataHandlerTest.java
index d46555dd6c4e..20ee9dc0602e 100644
--- a/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/handler/MultiPartFormDataHandlerTest.java
+++ b/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/handler/MultiPartFormDataHandlerTest.java
@@ -79,7 +79,7 @@ public void testSimpleMultiPart() throws Exception
             public boolean handle(Request request, Response response, Callback callback)
             {
                 String boundary = MultiPart.extractBoundary(request.getHeaders().get(HttpHeader.CONTENT_TYPE));
-                new MultiPartFormData(boundary).parse(request)
+                new MultiPartFormData(request, boundary).parse()
                     .whenComplete((parts, failure) ->
                     {
                         if (parts != null)
@@ -193,7 +193,7 @@ public void testEchoMultiPart() throws Exception
             public boolean handle(Request request, Response response, Callback callback)
             {
                 String boundary = MultiPart.extractBoundary(request.getHeaders().get(HttpHeader.CONTENT_TYPE));
-                new MultiPartFormData(boundary).parse(request)
+                new MultiPartFormData(request, boundary).parse()
                     .whenComplete((parts, failure) ->
                     {
                         if (parts != null)
@@ -310,9 +310,10 @@ public boolean handle(Request request, Response response, Callback callback)
             String boundary = MultiPart.extractBoundary(value);
             assertNotNull(boundary);
 
-            MultiPartFormData formData = new MultiPartFormData(boundary);
+            ByteBufferContentSource byteBufferContentSource = new ByteBufferContentSource(ByteBuffer.wrap(response.getContentBytes()));
+            MultiPartFormData formData = new MultiPartFormData(byteBufferContentSource, boundary);
             formData.setFilesDirectory(tempDir);
-            formData.parse(new ByteBufferContentSource(ByteBuffer.wrap(response.getContentBytes())));
+            formData.parse();
             MultiPartFormData.Parts parts = formData.join();
 
             assertEquals(2, parts.size());
diff --git a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletMultiPartFormData.java b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletMultiPartFormData.java
index fb04400c95b1..e5fb376388cf 100644
--- a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletMultiPartFormData.java
+++ b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletMultiPartFormData.java
@@ -16,7 +16,6 @@
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
-import java.nio.ByteBuffer;
 import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.Collection;
@@ -32,9 +31,8 @@
 import org.eclipse.jetty.io.ByteBufferPool;
 import org.eclipse.jetty.io.Connection;
 import org.eclipse.jetty.io.Content;
-import org.eclipse.jetty.io.RetainableByteBuffer;
+import org.eclipse.jetty.io.content.InputStreamContentSource;
 import org.eclipse.jetty.server.ConnectionMetaData;
-import org.eclipse.jetty.util.BufferUtil;
 import org.eclipse.jetty.util.IO;
 import org.eclipse.jetty.util.StringUtil;
 
@@ -105,7 +103,14 @@ private Parts parse(ServletApiRequest request, int maxParts) throws IOException
         // TODO we should look for an already done MultiPartFormData as an attribute, so it can be
         //      read asynchronously without blocking by something like the DelayedHandler (although
         //      probably need an in ServletContext variant to get the configuration below.
-        MultiPartFormData formData = new MultiPartFormData(boundary);
+
+        ByteBufferPool byteBufferPool = request.getRequest().getComponents().getByteBufferPool();
+        ConnectionMetaData connectionMetaData = request.getRequest().getConnectionMetaData();
+        Connection connection = connectionMetaData.getConnection();
+        int bufferSize = connection instanceof AbstractConnection c ? c.getInputBufferSize() : 2048;
+        InputStreamContentSource input = new InputStreamContentSource(request.getInputStream(), byteBufferPool);
+        input.setBufferSize(bufferSize);
+        MultiPartFormData formData = new MultiPartFormData(input, boundary);
         formData.setMaxParts(maxParts);
 
         File tmpDirFile = (File)request.getServletContext().getAttribute(ServletContext.TEMPDIR);
@@ -119,35 +124,9 @@ private Parts parse(ServletApiRequest request, int maxParts) throws IOException
         formData.setMaxMemoryFileSize(config.getFileSizeThreshold());
         formData.setMaxFileSize(config.getMaxFileSize());
         formData.setMaxLength(config.getMaxRequestSize());
-        ConnectionMetaData connectionMetaData = request.getRequest().getConnectionMetaData();
         formData.setPartHeadersMaxLength(connectionMetaData.getHttpConfiguration().getRequestHeaderSize());
 
-        ByteBufferPool byteBufferPool = request.getRequest().getComponents().getByteBufferPool();
-        Connection connection = connectionMetaData.getConnection();
-        int bufferSize = connection instanceof AbstractConnection c ? c.getInputBufferSize() : 2048;
-        InputStream input = request.getInputStream();
-        while (!formData.isDone())
-        {
-            RetainableByteBuffer retainable = byteBufferPool.acquire(bufferSize, false);
-            boolean readEof = false;
-            ByteBuffer buffer = retainable.getByteBuffer();
-            while (BufferUtil.space(buffer) > bufferSize / 2)
-            {
-                int read = BufferUtil.readFrom(input, buffer);
-                if (read < 0)
-                {
-                    readEof = true;
-                    break;
-                }
-            }
-
-            formData.parse(Content.Chunk.from(buffer, false, retainable::release));
-            if (readEof)
-            {
-                formData.parse(Content.Chunk.EOF);
-                break;
-            }
-        }
+        formData.parse();
 
         Parts parts = new Parts(formData.join());
         request.setAttribute(Parts.class.getName(), parts);

From 82001de46ac85418d9db6fee8caa7ac831be8cfd Mon Sep 17 00:00:00 2001
From: gregw <gregw@webtide.com>
Date: Tue, 27 Jun 2023 03:50:45 -0600
Subject: [PATCH 03/19] Experiment with a fully async
 ContentSourceCompletableFuture

WIP
---
 .../util/MultiPartRequestContentTest.java     |  4 +--
 .../jetty/server/handler/DelayedHandler.java  | 31 ++-----------------
 .../ee10/servlet/MultiPartServletTest.java    | 10 +++---
 3 files changed, 8 insertions(+), 37 deletions(-)

diff --git a/jetty-core/jetty-client/src/test/java/org/eclipse/jetty/client/util/MultiPartRequestContentTest.java b/jetty-core/jetty-client/src/test/java/org/eclipse/jetty/client/util/MultiPartRequestContentTest.java
index 1a03575314fd..15469ec402d8 100644
--- a/jetty-core/jetty-client/src/test/java/org/eclipse/jetty/client/util/MultiPartRequestContentTest.java
+++ b/jetty-core/jetty-client/src/test/java/org/eclipse/jetty/client/util/MultiPartRequestContentTest.java
@@ -439,9 +439,9 @@ public boolean handle(Request request, Response response, Callback callback) thr
             String contentType = request.getHeaders().get(HttpHeader.CONTENT_TYPE);
             assertEquals("multipart/form-data", HttpField.valueParameters(contentType, null));
             String boundary = MultiPart.extractBoundary(contentType);
-            MultiPartFormData formData = new MultiPartFormData(boundary);
+            MultiPartFormData formData = new MultiPartFormData(request, boundary);
             formData.setFilesDirectory(tmpDir);
-            formData.parse(request);
+            formData.parse();
             try
             {
                 process(formData.join()); // May block waiting for multipart form data.
diff --git a/jetty-core/jetty-server/src/main/java/org/eclipse/jetty/server/handler/DelayedHandler.java b/jetty-core/jetty-server/src/main/java/org/eclipse/jetty/server/handler/DelayedHandler.java
index 90ecf7449b96..b0b1bee8374e 100644
--- a/jetty-core/jetty-server/src/main/java/org/eclipse/jetty/server/handler/DelayedHandler.java
+++ b/jetty-core/jetty-server/src/main/java/org/eclipse/jetty/server/handler/DelayedHandler.java
@@ -13,7 +13,6 @@
 
 package org.eclipse.jetty.server.handler;
 
-import java.io.IOException;
 import java.nio.charset.Charset;
 import java.nio.charset.StandardCharsets;
 import java.util.Objects;
@@ -269,7 +268,7 @@ public UntilMultiPartDelayedProcess(Handler handler, Request wrapped, Response r
         {
             super(handler, wrapped, response, callback);
             String boundary = MultiPart.extractBoundary(contentType);
-            _formData = boundary == null ? null : new MultiPartFormData(boundary);
+            _formData = boundary == null ? null : new MultiPartFormData(wrapped, boundary);
         }
 
         private void process(MultiPartFormData.Parts parts, Throwable x)
@@ -309,7 +308,7 @@ public void delay()
             else
             {
                 _formData.setFilesDirectory(getRequest().getContext().getTempDirectory().toPath());
-                readAndParse();
+                _formData.parse();
                 // if we are done already, then we are still in the scope of the original process call and can
                 // process directly, otherwise we must execute a call to process as we are within a serialized
                 // demand callback.
@@ -331,31 +330,5 @@ public void delay()
                 }
             }
         }
-
-        private void readAndParse()
-        {
-            while (!_formData.isDone())
-            {
-                Content.Chunk chunk = getRequest().read();
-                if (chunk == null)
-                {
-                    getRequest().demand(this::readAndParse);
-                    return;
-                }
-                if (Content.Chunk.isFailure(chunk))
-                {
-                    _formData.completeExceptionally(chunk.getFailure());
-                    return;
-                }
-                _formData.parse(chunk);
-                chunk.release();
-                if (chunk.isLast())
-                {
-                    if (!_formData.isDone())
-                        process(null, new IOException("Incomplete multipart"));
-                    return;
-                }
-            }
-        }
     }
 }
diff --git a/jetty-ee10/jetty-ee10-servlet/src/test/java/org/eclipse/jetty/ee10/servlet/MultiPartServletTest.java b/jetty-ee10/jetty-ee10-servlet/src/test/java/org/eclipse/jetty/ee10/servlet/MultiPartServletTest.java
index 2ccbbde45b93..e89db59f54e6 100644
--- a/jetty-ee10/jetty-ee10-servlet/src/test/java/org/eclipse/jetty/ee10/servlet/MultiPartServletTest.java
+++ b/jetty-ee10/jetty-ee10-servlet/src/test/java/org/eclipse/jetty/ee10/servlet/MultiPartServletTest.java
@@ -17,7 +17,6 @@
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.net.Socket;
-import java.nio.ByteBuffer;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.Arrays;
@@ -52,8 +51,8 @@
 import org.eclipse.jetty.http.MultiPart;
 import org.eclipse.jetty.http.MultiPartFormData;
 import org.eclipse.jetty.io.ByteBufferPool;
-import org.eclipse.jetty.io.Content;
 import org.eclipse.jetty.io.EofException;
+import org.eclipse.jetty.io.content.InputStreamContentSource;
 import org.eclipse.jetty.logging.StacklessLogging;
 import org.eclipse.jetty.server.Server;
 import org.eclipse.jetty.server.ServerConnector;
@@ -409,11 +408,10 @@ protected void service(HttpServletRequest request, HttpServletResponse response)
 
         String contentType = headers.get(HttpHeader.CONTENT_TYPE);
         String boundary = MultiPart.extractBoundary(contentType);
-        MultiPartFormData formData = new MultiPartFormData(boundary);
-        formData.setMaxParts(1);
-
         InputStream inputStream = new GZIPInputStream(responseStream.getInputStream());
-        formData.parse(Content.Chunk.from(ByteBuffer.wrap(IO.readBytes(inputStream)), true));
+        MultiPartFormData formData = new MultiPartFormData(new InputStreamContentSource(inputStream), boundary);
+        formData.setMaxParts(1);
+        formData.parse();
         MultiPartFormData.Parts parts = formData.join();
 
         assertThat(parts.size(), is(1));

From d046fd89cd351f52d56fd1d405d9bf6c2b0b548f Mon Sep 17 00:00:00 2001
From: gregw <gregw@webtide.com>
Date: Tue, 27 Jun 2023 17:48:28 +0200
Subject: [PATCH 04/19] Experiment with a fully async
 ContentSourceCompletableFuture

WIP
---
 .../main/java/org/eclipse/jetty/http/MultiPartFormData.java | 2 --
 .../org/eclipse/jetty/ee10/servlet/ServletApiRequest.java   | 6 ++++++
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartFormData.java b/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartFormData.java
index 499507865f80..d403d466835b 100644
--- a/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartFormData.java
+++ b/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartFormData.java
@@ -69,8 +69,6 @@
  */
 public class MultiPartFormData extends ContentSourceCompletableFuture<MultiPartFormData.Parts>
 {
-    // TODO base the implementation on a ContentSourceCompletableFuture
-
     private static final Logger LOG = LoggerFactory.getLogger(MultiPartFormData.class);
 
     private final PartsListener listener = new PartsListener();
diff --git a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletApiRequest.java b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletApiRequest.java
index d1e1d1ab8add..2ef49f5d8306 100644
--- a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletApiRequest.java
+++ b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletApiRequest.java
@@ -501,6 +501,12 @@ public Collection<Part> getParts() throws IOException, ServletException
             int maxFormContentSize = contextHandler.getMaxFormContentSize();
             int maxFormKeys = contextHandler.getMaxFormKeys();
 
+            // TODO use the following
+            config.getFileSizeThreshold();
+            config.getLocation();
+            config.getMaxFileSize();
+            config.getMaxRequestSize();
+
             _parts = ServletMultiPartFormData.from(this, maxFormKeys);
             Collection<Part> parts = _parts.getParts();
 

From 564b594cfc3501541d3802fdfaf0d7f49f7b09e2 Mon Sep 17 00:00:00 2001
From: gregw <gregw@webtide.com>
Date: Wed, 28 Jun 2023 16:08:43 +0200
Subject: [PATCH 05/19] Experiment with a fully async
 ContentSourceCompletableFuture

Restructure MultiPartFormData to have a Parser class
---
 .../util/MultiPartRequestContentTest.java     |   6 +-
 .../eclipse/jetty/http/MultiPartFormData.java | 763 +++++++++---------
 .../jetty/http/MultiPartFormDataTest.java     | 135 ++--
 .../ContentSourceCompletableFuture.java       |   2 +-
 .../jetty/server/handler/DelayedHandler.java  |  12 +-
 .../handler/MultiPartFormDataHandlerTest.java |  40 +-
 .../servlet/ServletMultiPartFormData.java     |  25 +-
 .../ee10/servlet/MultiPartServletTest.java    |   5 +-
 8 files changed, 477 insertions(+), 511 deletions(-)

diff --git a/jetty-core/jetty-client/src/test/java/org/eclipse/jetty/client/util/MultiPartRequestContentTest.java b/jetty-core/jetty-client/src/test/java/org/eclipse/jetty/client/util/MultiPartRequestContentTest.java
index 15469ec402d8..f6b598f848ff 100644
--- a/jetty-core/jetty-client/src/test/java/org/eclipse/jetty/client/util/MultiPartRequestContentTest.java
+++ b/jetty-core/jetty-client/src/test/java/org/eclipse/jetty/client/util/MultiPartRequestContentTest.java
@@ -439,12 +439,12 @@ public boolean handle(Request request, Response response, Callback callback) thr
             String contentType = request.getHeaders().get(HttpHeader.CONTENT_TYPE);
             assertEquals("multipart/form-data", HttpField.valueParameters(contentType, null));
             String boundary = MultiPart.extractBoundary(contentType);
-            MultiPartFormData formData = new MultiPartFormData(request, boundary);
+            MultiPartFormData.Parser formData = new MultiPartFormData.Parser(boundary);
             formData.setFilesDirectory(tmpDir);
-            formData.parse();
+
             try
             {
-                process(formData.join()); // May block waiting for multipart form data.
+                process(formData.parse(request).join()); // May block waiting for multipart form data.
                 response.write(true, BufferUtil.EMPTY_BUFFER, callback);
             }
             catch (Exception x)
diff --git a/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartFormData.java b/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartFormData.java
index d403d466835b..8c03c96e08d9 100644
--- a/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartFormData.java
+++ b/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartFormData.java
@@ -67,205 +67,19 @@
  *
  * @see Parts
  */
-public class MultiPartFormData extends ContentSourceCompletableFuture<MultiPartFormData.Parts>
+public class MultiPartFormData
 {
     private static final Logger LOG = LoggerFactory.getLogger(MultiPartFormData.class);
 
-    private final PartsListener listener = new PartsListener();
-    private final MultiPart.Parser parser;
-    private boolean useFilesForPartsWithoutFileName;
-    private Path filesDirectory;
-    private long maxFileSize = -1;
-    private long maxMemoryFileSize;
-    private long maxLength = -1;
-    private long length;
-    private Parts parts;
-
-    public MultiPartFormData(Content.Source source, String boundary)
+    private MultiPartFormData()
     {
-        super(source);
-        parser = new MultiPart.Parser(Objects.requireNonNull(boundary), listener);
-    }
-
-    /**
-     * @return the boundary string
-     */
-    public String getBoundary()
-    {
-        return parser.getBoundary();
-    }
-
-    /**
-     * <p>Parses the given chunk containing multipart/form-data bytes.</p>
-     * <p>One or more chunks may be passed to this method, until the parsing
-     * of the multipart/form-data content completes.</p>
-     *
-     * @param chunk the {@link Content.Chunk} to parse.
-     */
-    @Override
-    protected MultiPartFormData.Parts parse(Content.Chunk chunk)
-    {
-        if (listener.isFailed())
-            return null;
-        length += chunk.getByteBuffer().remaining();
-        long max = getMaxLength();
-        if (max > 0 && length > max)
-            throw new IllegalStateException("max length exceeded: %d".formatted(max));
-        parser.parse(chunk);
-        return parts;
-    }
-
-    /**
-     * <p>Returns the default charset as specified by
-     * <a href="https://datatracker.ietf.org/doc/html/rfc7578#section-4.6">RFC 7578, section 4.6</a>,
-     * that is the charset specified by the part named {@code _charset_}.</p>
-     * <p>If that part is not present, returns {@code null}.</p>
-     *
-     * @return the default charset specified by the {@code _charset_} part,
-     * or null if that part is not present
-     */
-    public Charset getDefaultCharset()
-    {
-        return listener.getDefaultCharset();
-    }
-
-    /**
-     * @return the max length of a {@link MultiPart.Part} headers, in bytes, or -1 for unlimited length
-     */
-    public int getPartHeadersMaxLength()
-    {
-        return parser.getPartHeadersMaxLength();
-    }
-
-    /**
-     * @param partHeadersMaxLength the max length of a {@link MultiPart.Part} headers, in bytes, or -1 for unlimited length
-     */
-    public void setPartHeadersMaxLength(int partHeadersMaxLength)
-    {
-        parser.setPartHeadersMaxLength(partHeadersMaxLength);
-    }
-
-    /**
-     * @return whether parts without fileName may be stored as files
-     */
-    public boolean isUseFilesForPartsWithoutFileName()
-    {
-        return useFilesForPartsWithoutFileName;
-    }
-
-    /**
-     * @param useFilesForPartsWithoutFileName whether parts without fileName may be stored as files
-     */
-    public void setUseFilesForPartsWithoutFileName(boolean useFilesForPartsWithoutFileName)
-    {
-        this.useFilesForPartsWithoutFileName = useFilesForPartsWithoutFileName;
-    }
-
-    /**
-     * @return the directory where files are saved
-     */
-    public Path getFilesDirectory()
-    {
-        return filesDirectory;
-    }
-
-    /**
-     * <p>Sets the directory where the files uploaded in the parts will be saved.</p>
-     *
-     * @param filesDirectory the directory where files are saved
-     */
-    public void setFilesDirectory(Path filesDirectory)
-    {
-        this.filesDirectory = filesDirectory;
-    }
-
-    /**
-     * @return the maximum file size in bytes, or -1 for unlimited file size
-     */
-    public long getMaxFileSize()
-    {
-        return maxFileSize;
-    }
-
-    /**
-     * @param maxFileSize the maximum file size in bytes, or -1 for unlimited file size
-     */
-    public void setMaxFileSize(long maxFileSize)
-    {
-        this.maxFileSize = maxFileSize;
-    }
-
-    /**
-     * @return the maximum memory file size in bytes, or -1 for unlimited memory file size
-     */
-    public long getMaxMemoryFileSize()
-    {
-        return maxMemoryFileSize;
-    }
-
-    /**
-     * <p>Sets the maximum memory file size in bytes, after which files will be saved
-     * in the directory specified by {@link #setFilesDirectory(Path)}.</p>
-     * <p>Use value {@code 0} to always save the files in the directory.</p>
-     * <p>Use value {@code -1} to never save the files in the directory.</p>
-     *
-     * @param maxMemoryFileSize the maximum memory file size in bytes, or -1 for unlimited memory file size
-     */
-    public void setMaxMemoryFileSize(long maxMemoryFileSize)
-    {
-        this.maxMemoryFileSize = maxMemoryFileSize;
-    }
-
-    /**
-     * @return the maximum length in bytes of the whole multipart content, or -1 for unlimited length
-     */
-    public long getMaxLength()
-    {
-        return maxLength;
-    }
-
-    /**
-     * @param maxLength the maximum length in bytes of the whole multipart content, or -1 for unlimited length
-     */
-    public void setMaxLength(long maxLength)
-    {
-        this.maxLength = maxLength;
-    }
-
-    /**
-     * @return the maximum number of parts that can be parsed from the multipart content.
-     */
-    public long getMaxParts()
-    {
-        return parser.getMaxParts();
-    }
-
-    /**
-     * @param maxParts the maximum number of parts that can be parsed from the multipart content.
-     */
-    public void setMaxParts(long maxParts)
-    {
-        parser.setMaxParts(maxParts);
-    }
-
-    @Override
-    public boolean completeExceptionally(Throwable failure)
-    {
-        listener.fail(failure);
-        return super.completeExceptionally(failure);
-    }
-
-    // Only used for testing.
-    int getPartsSize()
-    {
-        return listener.getPartsSize();
     }
 
     /**
      * <p>An ordered list of {@link MultiPart.Part}s that can
      * be accessed by index or by name, or iterated over.</p>
      */
-    public class Parts implements Iterable<MultiPart.Part>, Closeable
+    public static class Parts implements Iterable<MultiPart.Part>, Closeable
     {
         private final List<MultiPart.Part> parts;
 
@@ -274,11 +88,6 @@ private Parts(List<MultiPart.Part> parts)
             this.parts = parts;
         }
 
-        public MultiPartFormData getMultiPartFormData()
-        {
-            return MultiPartFormData.this;
-        }
-
         /**
          * <p>Returns the {@link MultiPart.Part}  at the given index, a number
          * between {@code 0} included and the value returned by {@link #size()}
@@ -373,251 +182,445 @@ protected HttpFields customizePartHeaders(MultiPart.Part part)
         }
     }
 
-    private class PartsListener extends MultiPart.AbstractPartsListener
+    public static class Parser
     {
-        private final AutoLock lock = new AutoLock();
-        private final List<MultiPart.Part> parts = new ArrayList<>();
-        private final List<Content.Chunk> partChunks = new ArrayList<>();
-        private long fileSize;
-        private long memoryFileSize;
-        private Path filePath;
-        private SeekableByteChannel fileChannel;
-        private Throwable failure;
+        private final PartsListener listener = new PartsListener();
+        private final MultiPart.Parser parser;
+        private boolean useFilesForPartsWithoutFileName;
+        private Path filesDirectory;
+        private long maxFileSize = -1;
+        private long maxMemoryFileSize;
+        private long maxLength = -1;
+        private long length;
+        private Parts parts;
+
+        public Parser(String boundary)
+        {
+            parser = new MultiPart.Parser(Objects.requireNonNull(boundary), listener);
+        }
 
-        @Override
-        public void onPartContent(Content.Chunk chunk)
+        public CompletableFuture<Parts> parse(Content.Source content)
         {
-            ByteBuffer buffer = chunk.getByteBuffer();
-            String fileName = getFileName();
-            if (fileName != null || isUseFilesForPartsWithoutFileName())
+            ContentSourceCompletableFuture<Parts> futureParts = new ContentSourceCompletableFuture<>(content)
             {
-                long maxFileSize = getMaxFileSize();
-                fileSize += buffer.remaining();
-                if (maxFileSize >= 0 && fileSize > maxFileSize)
+                @Override
+                protected Parts parse(Content.Chunk chunk) throws Throwable
                 {
-                    onFailure(new IllegalStateException("max file size exceeded: %d".formatted(maxFileSize)));
-                    return;
+                    if (listener.isFailed())
+                        throw listener.failure;
+                    length += chunk.getByteBuffer().remaining();
+                    long max = getMaxLength();
+                    if (max > 0 && length > max)
+                        throw new IllegalStateException("max length exceeded: %d".formatted(max));
+                    parser.parse(chunk);
+                    if (listener.isFailed())
+                        throw listener.failure;
+                    return parts;
                 }
 
-                long maxMemoryFileSize = getMaxMemoryFileSize();
-                if (maxMemoryFileSize >= 0)
+                @Override
+                public boolean completeExceptionally(Throwable failure)
                 {
-                    memoryFileSize += buffer.remaining();
-                    if (memoryFileSize > maxMemoryFileSize)
+                    listener.fail(failure);
+                    return super.completeExceptionally(failure);
+                }
+            };
+            futureParts.parse();
+            return futureParts;
+        }
+
+        /**
+         * @return the boundary string
+         */
+        public String getBoundary()
+        {
+            return parser.getBoundary();
+        }
+
+        /**
+         * <p>Returns the default charset as specified by
+         * <a href="https://datatracker.ietf.org/doc/html/rfc7578#section-4.6">RFC 7578, section 4.6</a>,
+         * that is the charset specified by the part named {@code _charset_}.</p>
+         * <p>If that part is not present, returns {@code null}.</p>
+         *
+         * @return the default charset specified by the {@code _charset_} part,
+         * or null if that part is not present
+         */
+        public Charset getDefaultCharset()
+        {
+            return listener.getDefaultCharset();
+        }
+
+        /**
+         * @return the max length of a {@link MultiPart.Part} headers, in bytes, or -1 for unlimited length
+         */
+        public int getPartHeadersMaxLength()
+        {
+            return parser.getPartHeadersMaxLength();
+        }
+
+        /**
+         * @param partHeadersMaxLength the max length of a {@link MultiPart.Part} headers, in bytes, or -1 for unlimited length
+         */
+        public void setPartHeadersMaxLength(int partHeadersMaxLength)
+        {
+            parser.setPartHeadersMaxLength(partHeadersMaxLength);
+        }
+
+        /**
+         * @return whether parts without fileName may be stored as files
+         */
+        public boolean isUseFilesForPartsWithoutFileName()
+        {
+            return useFilesForPartsWithoutFileName;
+        }
+
+        /**
+         * @param useFilesForPartsWithoutFileName whether parts without fileName may be stored as files
+         */
+        public void setUseFilesForPartsWithoutFileName(boolean useFilesForPartsWithoutFileName)
+        {
+            this.useFilesForPartsWithoutFileName = useFilesForPartsWithoutFileName;
+        }
+
+        /**
+         * @return the directory where files are saved
+         */
+        public Path getFilesDirectory()
+        {
+            return filesDirectory;
+        }
+
+        /**
+         * <p>Sets the directory where the files uploaded in the parts will be saved.</p>
+         *
+         * @param filesDirectory the directory where files are saved
+         */
+        public void setFilesDirectory(Path filesDirectory)
+        {
+            this.filesDirectory = filesDirectory;
+        }
+
+        /**
+         * @return the maximum file size in bytes, or -1 for unlimited file size
+         */
+        public long getMaxFileSize()
+        {
+            return maxFileSize;
+        }
+
+        /**
+         * @param maxFileSize the maximum file size in bytes, or -1 for unlimited file size
+         */
+        public void setMaxFileSize(long maxFileSize)
+        {
+            this.maxFileSize = maxFileSize;
+        }
+
+        /**
+         * @return the maximum memory file size in bytes, or -1 for unlimited memory file size
+         */
+        public long getMaxMemoryFileSize()
+        {
+            return maxMemoryFileSize;
+        }
+
+        /**
+         * <p>Sets the maximum memory file size in bytes, after which files will be saved
+         * in the directory specified by {@link #setFilesDirectory(Path)}.</p>
+         * <p>Use value {@code 0} to always save the files in the directory.</p>
+         * <p>Use value {@code -1} to never save the files in the directory.</p>
+         *
+         * @param maxMemoryFileSize the maximum memory file size in bytes, or -1 for unlimited memory file size
+         */
+        public void setMaxMemoryFileSize(long maxMemoryFileSize)
+        {
+            this.maxMemoryFileSize = maxMemoryFileSize;
+        }
+
+        /**
+         * @return the maximum length in bytes of the whole multipart content, or -1 for unlimited length
+         */
+        public long getMaxLength()
+        {
+            return maxLength;
+        }
+
+        /**
+         * @param maxLength the maximum length in bytes of the whole multipart content, or -1 for unlimited length
+         */
+        public void setMaxLength(long maxLength)
+        {
+            this.maxLength = maxLength;
+        }
+
+        /**
+         * @return the maximum number of parts that can be parsed from the multipart content.
+         */
+        public long getMaxParts()
+        {
+            return parser.getMaxParts();
+        }
+
+        /**
+         * @param maxParts the maximum number of parts that can be parsed from the multipart content.
+         */
+        public void setMaxParts(long maxParts)
+        {
+            parser.setMaxParts(maxParts);
+        }
+
+        // Only used for testing.
+        int getPartsSize()
+        {
+            return listener.getPartsSize();
+        }
+
+        private class PartsListener extends MultiPart.AbstractPartsListener
+        {
+            private final AutoLock lock = new AutoLock(); // TODO why do we need this lock?
+            private final List<MultiPart.Part> parts = new ArrayList<>();
+            private final List<Content.Chunk> partChunks = new ArrayList<>();
+            private long fileSize;
+            private long memoryFileSize;
+            private Path filePath;
+            private SeekableByteChannel fileChannel;
+            private Throwable failure;
+
+            @Override
+            public void onPartContent(Content.Chunk chunk)
+            {
+                ByteBuffer buffer = chunk.getByteBuffer();
+                String fileName = getFileName();
+                if (fileName != null || isUseFilesForPartsWithoutFileName())
+                {
+                    long maxFileSize = getMaxFileSize();
+                    fileSize += buffer.remaining();
+                    if (maxFileSize >= 0 && fileSize > maxFileSize)
+                    {
+                        onFailure(new IllegalStateException("max file size exceeded: %d".formatted(maxFileSize)));
+                        return;
+                    }
+
+                    long maxMemoryFileSize = getMaxMemoryFileSize();
+                    if (maxMemoryFileSize >= 0)
                     {
-                        try
+                        memoryFileSize += buffer.remaining();
+                        if (memoryFileSize > maxMemoryFileSize)
                         {
-                            // Must save to disk.
-                            if (ensureFileChannel())
+                            try
                             {
-                                // Write existing memory chunks.
-                                List<Content.Chunk> partChunks;
-                                try (AutoLock ignored = lock.lock())
+                                // Must save to disk.
+                                if (ensureFileChannel())
                                 {
-                                    partChunks = List.copyOf(this.partChunks);
-                                }
-                                for (Content.Chunk c : partChunks)
-                                {
-                                    write(c.getByteBuffer());
+                                    // Write existing memory chunks.
+                                    List<Content.Chunk> partChunks;
+                                    try (AutoLock ignored = lock.lock())
+                                    {
+                                        partChunks = List.copyOf(this.partChunks);
+                                    }
+                                    for (Content.Chunk c : partChunks)
+                                    {
+                                        write(c.getByteBuffer());
+                                    }
                                 }
+                                write(buffer);
+                                if (chunk.isLast())
+                                    close();
+                            }
+                            catch (Throwable x)
+                            {
+                                onFailure(x);
                             }
-                            write(buffer);
-                            if (chunk.isLast())
-                                close();
-                        }
-                        catch (Throwable x)
-                        {
-                            onFailure(x);
-                        }
 
-                        try (AutoLock ignored = lock.lock())
-                        {
-                            partChunks.forEach(Content.Chunk::release);
-                            partChunks.clear();
+                            try (AutoLock ignored = lock.lock())
+                            {
+                                partChunks.forEach(Content.Chunk::release);
+                                partChunks.clear();
+                            }
+                            return;
                         }
-                        return;
                     }
                 }
+                // Retain the chunk because it is stored for later use.
+                chunk.retain();
+                try (AutoLock ignored = lock.lock())
+                {
+                    partChunks.add(chunk);
+                }
             }
-            // Retain the chunk because it is stored for later use.
-            chunk.retain();
-            try (AutoLock ignored = lock.lock())
-            {
-                partChunks.add(chunk);
-            }
-        }
 
-        private void write(ByteBuffer buffer) throws Exception
-        {
-            int remaining = buffer.remaining();
-            while (remaining > 0)
+            private void write(ByteBuffer buffer) throws Exception
             {
-                SeekableByteChannel channel = fileChannel();
-                if (channel == null)
-                    throw new IllegalStateException();
-                int written = channel.write(buffer);
-                if (written == 0)
-                    throw new NonWritableChannelException();
-                remaining -= written;
+                int remaining = buffer.remaining();
+                while (remaining > 0)
+                {
+                    SeekableByteChannel channel = fileChannel();
+                    if (channel == null)
+                        throw new IllegalStateException();
+                    int written = channel.write(buffer);
+                    if (written == 0)
+                        throw new NonWritableChannelException();
+                    remaining -= written;
+                }
             }
-        }
 
-        private void close()
-        {
-            try
+            private void close()
             {
-                Closeable closeable = fileChannel();
-                if (closeable != null)
-                    closeable.close();
-            }
-            catch (Throwable x)
-            {
-                onFailure(x);
+                try
+                {
+                    Closeable closeable = fileChannel();
+                    if (closeable != null)
+                        closeable.close();
+                }
+                catch (Throwable x)
+                {
+                    onFailure(x);
+                }
             }
-        }
 
-        @Override
-        public void onPart(String name, String fileName, HttpFields headers)
-        {
-            fileSize = 0;
-            memoryFileSize = 0;
-            try (AutoLock ignored = lock.lock())
+            @Override
+            public void onPart(String name, String fileName, HttpFields headers)
             {
-                MultiPart.Part part;
-                if (fileChannel != null)
-                    part = new MultiPart.PathPart(name, fileName, headers, filePath);
-                else
-                    part = new MultiPart.ChunksPart(name, fileName, headers, List.copyOf(partChunks));
-                // Reset part-related state.
-                filePath = null;
-                fileChannel = null;
-                partChunks.forEach(Content.Chunk::release);
-                partChunks.clear();
-                // Store the new part.
-                parts.add(part);
+                fileSize = 0;
+                memoryFileSize = 0;
+                try (AutoLock ignored = lock.lock())
+                {
+                    MultiPart.Part part;
+                    if (fileChannel != null)
+                        part = new MultiPart.PathPart(name, fileName, headers, filePath);
+                    else
+                        part = new MultiPart.ChunksPart(name, fileName, headers, List.copyOf(partChunks));
+                    // Reset part-related state.
+                    filePath = null;
+                    fileChannel = null;
+                    partChunks.forEach(Content.Chunk::release);
+                    partChunks.clear();
+                    // Store the new part.
+                    parts.add(part);
+                }
             }
-        }
 
-        @Override
-        public void onComplete()
-        {
-            super.onComplete();
-            List<MultiPart.Part> result;
-            try (AutoLock ignored = lock.lock())
+            @Override
+            public void onComplete()
             {
-                result = List.copyOf(parts);
-                MultiPartFormData.this.parts = new Parts(result);
+                super.onComplete();
+                List<MultiPart.Part> result;
+                try (AutoLock ignored = lock.lock())
+                {
+                    result = List.copyOf(parts);
+                    Parser.this.parts = new Parts(result);
+                }
             }
-        }
 
-        Charset getDefaultCharset()
-        {
-            try (AutoLock ignored = lock.lock())
+            Charset getDefaultCharset()
             {
-                return parts.stream()
-                    .filter(part -> "_charset_".equals(part.getName()))
-                    .map(part -> part.getContentAsString(US_ASCII))
-                    .map(Charset::forName)
-                    .findFirst()
-                    .orElse(null);
+                try (AutoLock ignored = lock.lock())
+                {
+                    return parts.stream()
+                        .filter(part -> "_charset_".equals(part.getName()))
+                        .map(part -> part.getContentAsString(US_ASCII))
+                        .map(Charset::forName)
+                        .findFirst()
+                        .orElse(null);
+                }
             }
-        }
 
-        int getPartsSize()
-        {
-            try (AutoLock ignored = lock.lock())
+            int getPartsSize()
             {
-                return parts.size();
+                try (AutoLock ignored = lock.lock())
+                {
+                    return parts.size();
+                }
             }
-        }
 
-        @Override
-        public void onFailure(Throwable failure)
-        {
-            super.onFailure(failure);
-            completeExceptionally(failure); // TODO not here
-        }
-
-        private void fail(Throwable cause)
-        {
-            List<MultiPart.Part> partsToFail;
-            try (AutoLock ignored = lock.lock())
+            @Override
+            public void onFailure(Throwable failure)
             {
-                if (failure != null)
-                    return;
-                failure = cause;
-                partsToFail = List.copyOf(parts);
-                parts.clear();
-                partChunks.forEach(Content.Chunk::release);
-                partChunks.clear();
+                fail(failure);
             }
-            partsToFail.forEach(p -> p.fail(cause));
-            close();
-            delete();
-        }
 
-        private SeekableByteChannel fileChannel()
-        {
-            try (AutoLock ignored = lock.lock())
+            private void fail(Throwable cause)
             {
-                return fileChannel;
+                List<MultiPart.Part> partsToFail;
+                try (AutoLock ignored = lock.lock())
+                {
+                    if (failure != null)
+                        return;
+                    failure = cause;
+                    partsToFail = List.copyOf(parts);
+                    parts.clear();
+                    partChunks.forEach(Content.Chunk::release);
+                    partChunks.clear();
+                }
+                partsToFail.forEach(p -> p.fail(cause));
+                close();
+                delete();
             }
-        }
 
-        private void delete()
-        {
-            try
+            private SeekableByteChannel fileChannel()
             {
-                Path path = null;
                 try (AutoLock ignored = lock.lock())
                 {
-                    if (filePath != null)
-                        path = filePath;
-                    filePath = null;
-                    fileChannel = null;
+                    return fileChannel;
                 }
-                if (path != null)
-                    Files.delete(path);
-            }
-            catch (Throwable x)
-            {
-                if (LOG.isTraceEnabled())
-                    LOG.trace("IGNORED", x);
             }
-        }
 
-        private boolean isFailed()
-        {
-            try (AutoLock ignored = lock.lock())
+            private void delete()
             {
-                return failure != null;
+                try
+                {
+                    Path path = null;
+                    try (AutoLock ignored = lock.lock())
+                    {
+                        if (filePath != null)
+                            path = filePath;
+                        filePath = null;
+                        fileChannel = null;
+                    }
+                    if (path != null)
+                        Files.delete(path);
+                }
+                catch (Throwable x)
+                {
+                    if (LOG.isTraceEnabled())
+                        LOG.trace("IGNORED", x);
+                }
             }
-        }
 
-        private boolean ensureFileChannel()
-        {
-            try (AutoLock ignored = lock.lock())
+            private boolean isFailed()
             {
-                if (fileChannel != null)
-                    return false;
-                createFileChannel();
-                return true;
+                try (AutoLock ignored = lock.lock())
+                {
+                    return failure != null;
+                }
             }
-        }
 
-        private void createFileChannel()
-        {
-            try (AutoLock ignored = lock.lock())
+            private boolean ensureFileChannel()
             {
-                Path directory = getFilesDirectory();
-                Files.createDirectories(directory);
-                String fileName = "MultiPart";
-                filePath = Files.createTempFile(directory, fileName, "");
-                fileChannel = Files.newByteChannel(filePath, StandardOpenOption.WRITE, StandardOpenOption.APPEND);
+                try (AutoLock ignored = lock.lock())
+                {
+                    if (fileChannel != null)
+                        return false;
+                    createFileChannel();
+                    return true;
+                }
             }
-            catch (Throwable x)
+
+            private void createFileChannel()
             {
-                onFailure(x);
+                try (AutoLock ignored = lock.lock())
+                {
+                    Path directory = getFilesDirectory();
+                    Files.createDirectories(directory);
+                    String fileName = "MultiPart";
+                    filePath = Files.createTempFile(directory, fileName, "");
+                    fileChannel = Files.newByteChannel(filePath, StandardOpenOption.WRITE, StandardOpenOption.APPEND);
+                }
+                catch (Throwable x)
+                {
+                    onFailure(x);
+                }
             }
         }
     }
diff --git a/jetty-core/jetty-http/src/test/java/org/eclipse/jetty/http/MultiPartFormDataTest.java b/jetty-core/jetty-http/src/test/java/org/eclipse/jetty/http/MultiPartFormDataTest.java
index 3fa1ffa2ec07..823b90d4a1a3 100644
--- a/jetty-core/jetty-http/src/test/java/org/eclipse/jetty/http/MultiPartFormDataTest.java
+++ b/jetty-core/jetty-http/src/test/java/org/eclipse/jetty/http/MultiPartFormDataTest.java
@@ -20,6 +20,7 @@
 import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicInteger;
@@ -97,15 +98,13 @@ public void testBadMultiPart() throws Exception
             "\r\n";
 
         AsyncContent source = new TestContent();
-        MultiPartFormData formData = new MultiPartFormData(source, boundary);
+        MultiPartFormData.Parser formData = new MultiPartFormData.Parser(boundary);
         formData.setFilesDirectory(_tmpDir);
         formData.setMaxFileSize(1024);
         formData.setMaxLength(3072);
         formData.setMaxMemoryFileSize(50);
         Content.Sink.write(source, true, str, Callback.NOOP);
-        formData.parse();
-
-        formData.handle((parts, failure) ->
+        formData.parse(source).handle((parts, failure) ->
         {
             assertNull(parts);
             assertInstanceOf(BadMessageException.class, failure);
@@ -129,15 +128,13 @@ public void testFinalBoundaryOnly() throws Exception
             "--" + boundary + "--" + eol;
 
         AsyncContent source = new TestContent();
-        MultiPartFormData formData = new MultiPartFormData(source, boundary);
+        MultiPartFormData.Parser formData = new MultiPartFormData.Parser(boundary);
         formData.setFilesDirectory(_tmpDir);
         formData.setMaxFileSize(1024);
         formData.setMaxLength(3072);
         formData.setMaxMemoryFileSize(50);
         Content.Sink.write(source, true, str, Callback.NOOP);
-        formData.parse();
-
-        formData.whenComplete((parts, failure) ->
+        formData.parse(source).whenComplete((parts, failure) ->
         {
             // No errors and no parts.
             assertNull(failure);
@@ -157,15 +154,13 @@ public void testEmpty() throws Exception
             "--" + boundary + "--" + eol;
 
         AsyncContent source = new TestContent();
-        MultiPartFormData formData = new MultiPartFormData(source, boundary);
+        MultiPartFormData.Parser formData = new MultiPartFormData.Parser(boundary);
         formData.setFilesDirectory(_tmpDir);
         formData.setMaxFileSize(1024);
         formData.setMaxLength(3072);
         formData.setMaxMemoryFileSize(50);
         Content.Sink.write(source, true, str, Callback.NOOP);
-        formData.parse();
-
-        formData.whenComplete((parts, failure) ->
+        formData.parse(source).whenComplete((parts, failure) ->
         {
             // No errors and no parts.
             assertNull(failure);
@@ -207,15 +202,13 @@ public void testEmptyStringBoundary() throws Exception
             """;
 
         AsyncContent source = new TestContent();
-        MultiPartFormData formData = new MultiPartFormData(source, "");
+        MultiPartFormData.Parser formData = new MultiPartFormData.Parser("");
         formData.setFilesDirectory(_tmpDir);
         formData.setMaxFileSize(1024);
         formData.setMaxLength(3072);
         formData.setMaxMemoryFileSize(50);
         Content.Sink.write(source, true, str, Callback.NOOP);
-        formData.parse();
-
-        try (MultiPartFormData.Parts parts = formData.get(5, TimeUnit.SECONDS))
+        try (MultiPartFormData.Parts parts = formData.parse(source).get(5, TimeUnit.SECONDS))
         {
             assertThat(parts.size(), is(4));
 
@@ -249,11 +242,9 @@ public void testEmptyStringBoundary() throws Exception
     public void testNoBody() throws Exception
     {
         AsyncContent source = new TestContent();
-        MultiPartFormData formData = new MultiPartFormData(source, "boundary");
+        MultiPartFormData.Parser formData = new MultiPartFormData.Parser("boundary");
         source.close();
-        formData.parse();
-
-        formData.handle((parts, failure) ->
+        formData.parse(source).handle((parts, failure) ->
         {
             assertNull(parts);
             assertNotNull(failure);
@@ -266,12 +257,10 @@ public void testNoBody() throws Exception
     public void testBodyWithOnlyCRLF() throws Exception
     {
         AsyncContent source = new TestContent();
-        MultiPartFormData formData = new MultiPartFormData(source, "boundary");
+        MultiPartFormData.Parser formData = new MultiPartFormData.Parser("boundary");
         String body = "              \n\n\n\r\n\r\n\r\n\r\n";
         Content.Sink.write(source, true, body, Callback.NOOP);
-        formData.parse();
-
-        formData.handle((parts, failure) ->
+        formData.parse(source).handle((parts, failure) ->
         {
             assertNull(parts);
             assertNotNull(failure);
@@ -303,15 +292,13 @@ public void testLeadingWhitespaceBodyWithCRLF() throws Exception
             """;
 
         AsyncContent source = new TestContent();
-        MultiPartFormData formData = new MultiPartFormData(source, "AaB03x");
+        MultiPartFormData.Parser formData = new MultiPartFormData.Parser("AaB03x");
         formData.setFilesDirectory(_tmpDir);
         formData.setMaxFileSize(1024);
         formData.setMaxLength(3072);
         formData.setMaxMemoryFileSize(50);
         Content.Sink.write(source, true, body, Callback.NOOP);
-        formData.parse();
-
-        try (MultiPartFormData.Parts parts = formData.get(5, TimeUnit.SECONDS))
+        try (MultiPartFormData.Parts parts = formData.parse(source).get(5, TimeUnit.SECONDS))
         {
             assertThat(parts.size(), is(2));
             MultiPart.Part part1 = parts.getFirst("field1");
@@ -342,15 +329,13 @@ public void testLeadingWhitespaceBodyWithoutCRLF() throws Exception
             """;
 
         AsyncContent source = new TestContent();
-        MultiPartFormData formData = new MultiPartFormData(source, "AaB03x");
+        MultiPartFormData.Parser formData = new MultiPartFormData.Parser("AaB03x");
         formData.setFilesDirectory(_tmpDir);
         formData.setMaxFileSize(1024);
         formData.setMaxLength(3072);
         formData.setMaxMemoryFileSize(50);
         Content.Sink.write(source, true, body, Callback.NOOP);
-        formData.parse();
-
-        try (MultiPartFormData.Parts parts = formData.get(5, TimeUnit.SECONDS))
+        try (MultiPartFormData.Parts parts = formData.parse(source).get(5, TimeUnit.SECONDS))
         {
             // The first boundary must be on a new line, so the first "part" is not recognized as such.
             assertThat(parts.size(), is(1));
@@ -365,7 +350,7 @@ public void testLeadingWhitespaceBodyWithoutCRLF() throws Exception
     public void testDefaultLimits() throws Exception
     {
         AsyncContent source = new TestContent();
-        MultiPartFormData formData = new MultiPartFormData(source, "AaB03x");
+        MultiPartFormData.Parser formData = new MultiPartFormData.Parser("AaB03x");
         formData.setFilesDirectory(_tmpDir);
         String body = """
             --AaB03x\r
@@ -376,9 +361,7 @@ public void testDefaultLimits() throws Exception
             --AaB03x--\r
             """;
         Content.Sink.write(source, true, body, Callback.NOOP);
-        formData.parse();
-
-        try (MultiPartFormData.Parts parts = formData.get(5, TimeUnit.SECONDS))
+        try (MultiPartFormData.Parts parts = formData.parse(source).get(5, TimeUnit.SECONDS))
         {
             assertThat(parts.size(), is(1));
             MultiPart.Part part = parts.get(0);
@@ -396,7 +379,7 @@ public void testDefaultLimits() throws Exception
     public void testRequestContentTooBig() throws Exception
     {
         AsyncContent source = new TestContent();
-        MultiPartFormData formData = new MultiPartFormData(source, "AaB03x");
+        MultiPartFormData.Parser formData = new MultiPartFormData.Parser("AaB03x");
         formData.setFilesDirectory(_tmpDir);
         formData.setMaxLength(16);
 
@@ -409,9 +392,7 @@ public void testRequestContentTooBig() throws Exception
             --AaB03x--\r
             """;
         Content.Sink.write(source, true, body, Callback.NOOP);
-        formData.parse();
-
-        formData.handle((parts, failure) ->
+        formData.parse(source).handle((parts, failure) ->
         {
             assertNull(parts);
             assertNotNull(failure);
@@ -424,7 +405,7 @@ public void testRequestContentTooBig() throws Exception
     public void testFileTooBig() throws Exception
     {
         AsyncContent source = new TestContent();
-        MultiPartFormData formData = new MultiPartFormData(source, "AaB03x");
+        MultiPartFormData.Parser formData = new MultiPartFormData.Parser("AaB03x");
         formData.setFilesDirectory(_tmpDir);
         formData.setMaxFileSize(16);
 
@@ -437,9 +418,7 @@ public void testFileTooBig() throws Exception
             --AaB03x--\r
             """;
         Content.Sink.write(source, true, body, Callback.NOOP);
-        formData.parse();
-
-        formData.handle((parts, failure) ->
+        formData.parse(source).handle((parts, failure) ->
         {
             assertNull(parts);
             assertNotNull(failure);
@@ -452,7 +431,7 @@ public void testFileTooBig() throws Exception
     public void testTwoFilesOneInMemoryOneOnDisk() throws Exception
     {
         AsyncContent source = new TestContent();
-        MultiPartFormData formData = new MultiPartFormData(source, "AaB03x");
+        MultiPartFormData.Parser formData = new MultiPartFormData.Parser("AaB03x");
         formData.setFilesDirectory(_tmpDir);
         String chunk = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
         formData.setMaxMemoryFileSize(chunk.length() + 1);
@@ -471,9 +450,7 @@ public void testTwoFilesOneInMemoryOneOnDisk() throws Exception
             --AaB03x--\r
             """.replace("$C", chunk);
         Content.Sink.write(source, true, body, Callback.NOOP);
-        formData.parse();
-
-        try (MultiPartFormData.Parts parts = formData.get(5, TimeUnit.SECONDS))
+        try (MultiPartFormData.Parts parts = formData.parse(source).get(5, TimeUnit.SECONDS))
         {
             assertNotNull(parts);
             assertEquals(2, parts.size());
@@ -494,7 +471,7 @@ public void testTwoFilesOneInMemoryOneOnDisk() throws Exception
     public void testPartWrite() throws Exception
     {
         AsyncContent source = new TestContent();
-        MultiPartFormData formData = new MultiPartFormData(source, "AaB03x");
+        MultiPartFormData.Parser formData = new MultiPartFormData.Parser("AaB03x");
         formData.setFilesDirectory(_tmpDir);
         String chunk = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
         formData.setMaxMemoryFileSize(chunk.length() + 1);
@@ -513,9 +490,7 @@ public void testPartWrite() throws Exception
             --AaB03x--\r
             """.replace("$C", chunk);
         Content.Sink.write(source, true, body, Callback.NOOP);
-        formData.parse();
-
-        try (MultiPartFormData.Parts parts = formData.get(5, TimeUnit.SECONDS))
+        try (MultiPartFormData.Parts parts = formData.parse(source).get(5, TimeUnit.SECONDS))
         {
             assertNotNull(parts);
             assertEquals(2, parts.size());
@@ -542,7 +517,7 @@ public void testPartWrite() throws Exception
     public void testPathPartDelete() throws Exception
     {
         AsyncContent source = new TestContent();
-        MultiPartFormData formData = new MultiPartFormData(source, "AaB03x");
+        MultiPartFormData.Parser formData = new MultiPartFormData.Parser("AaB03x");
         formData.setFilesDirectory(_tmpDir);
 
         String body = """
@@ -554,9 +529,7 @@ public void testPathPartDelete() throws Exception
             --AaB03x--\r
             """;
         Content.Sink.write(source, true, body, Callback.NOOP);
-        formData.parse();
-
-        try (MultiPartFormData.Parts parts = formData.get(5, TimeUnit.SECONDS))
+        try (MultiPartFormData.Parts parts = formData.parse(source).get(5, TimeUnit.SECONDS))
         {
             assertNotNull(parts);
             assertEquals(1, parts.size());
@@ -575,7 +548,7 @@ public void testPathPartDelete() throws Exception
     public void testAbort()
     {
         AsyncContent source = new TestContent();
-        MultiPartFormData formData = new MultiPartFormData(source, "AaB03x");
+        MultiPartFormData.Parser formData = new MultiPartFormData.Parser("AaB03x");
         formData.setFilesDirectory(_tmpDir);
         formData.setMaxMemoryFileSize(32);
 
@@ -592,17 +565,18 @@ public void testAbort()
             """;
         // Parse only part of the content.
         Content.Sink.write(source, false, body, Callback.NOOP);
-        formData.parse();
+
+        CompletableFuture<MultiPartFormData.Parts> futureParts = formData.parse(source);
         assertEquals(1, formData.getPartsSize());
 
         // Abort MultiPartFormData.
-        formData.completeExceptionally(new IOException());
+        futureParts.completeExceptionally(new IOException());
 
         // Parse the rest of the content.
         Content.Sink.write(source, true, terminator, Callback.NOOP);
 
         // Try to get the parts, it should fail.
-        assertThrows(ExecutionException.class, () -> formData.get(5, TimeUnit.SECONDS));
+        assertThrows(ExecutionException.class, () -> futureParts.get(5, TimeUnit.SECONDS));
         assertEquals(0, formData.getPartsSize());
     }
 
@@ -610,7 +584,7 @@ public void testAbort()
     public void testMaxHeaderLength() throws Exception
     {
         AsyncContent source = new TestContent();
-        MultiPartFormData formData = new MultiPartFormData(source, "AaB03x");
+        MultiPartFormData.Parser formData = new MultiPartFormData.Parser("AaB03x");
         formData.setFilesDirectory(_tmpDir);
         formData.setPartHeadersMaxLength(32);
 
@@ -622,10 +596,8 @@ public void testMaxHeaderLength() throws Exception
             ABCDEFGHIJKLMNOPQRSTUVWXYZ\r
             --AaB03x--\r
             """;
-        formData.parse();
         Content.Sink.write(source, true, body, Callback.NOOP);
-
-        formData.handle((parts, failure) ->
+        formData.parse(source).handle((parts, failure) ->
         {
             assertNull(parts);
             assertNotNull(failure);
@@ -638,7 +610,7 @@ public void testMaxHeaderLength() throws Exception
     public void testDefaultCharset() throws Exception
     {
         AsyncContent source = new TestContent();
-        MultiPartFormData formData = new MultiPartFormData(source, "AaB03x");
+        MultiPartFormData.Parser formData = new MultiPartFormData.Parser("AaB03x");
         formData.setFilesDirectory(_tmpDir);
         formData.setMaxMemoryFileSize(-1);
 
@@ -665,14 +637,14 @@ public void testDefaultCharset() throws Exception
             \r
             --AaB03x--\r
             """;
-        formData.parse();
+        CompletableFuture<MultiPartFormData.Parts> futureParts = formData.parse(source);
         Content.Sink.write(source, false, body1, Callback.NOOP);
         source.write(false, isoCedilla, Callback.NOOP);
         Content.Sink.write(source, false, body2, Callback.NOOP);
         source.write(false, utfCedilla, Callback.NOOP);
         Content.Sink.write(source, true, terminator, Callback.NOOP);
 
-        try (MultiPartFormData.Parts parts = formData.get(5, TimeUnit.SECONDS))
+        try (MultiPartFormData.Parts parts = futureParts.get(5, TimeUnit.SECONDS))
         {
             Charset defaultCharset = formData.getDefaultCharset();
             assertEquals(ISO_8859_1, defaultCharset);
@@ -691,7 +663,7 @@ public void testDefaultCharset() throws Exception
     public void testPartWithBackSlashInFileName() throws Exception
     {
         AsyncContent source = new TestContent();
-        MultiPartFormData formData = new MultiPartFormData(source, "AaB03x");
+        MultiPartFormData.Parser formData = new MultiPartFormData.Parser("AaB03x");
         formData.setFilesDirectory(_tmpDir);
         formData.setMaxMemoryFileSize(-1);
 
@@ -703,10 +675,9 @@ public void testPartWithBackSlashInFileName() throws Exception
             stuffaaa\r
             --AaB03x--\r
             """;
-        formData.parse();
         Content.Sink.write(source, true, contents, Callback.NOOP);
 
-        try (MultiPartFormData.Parts parts = formData.get(5, TimeUnit.SECONDS))
+        try (MultiPartFormData.Parts parts = formData.parse(source).get(5, TimeUnit.SECONDS))
         {
             assertThat(parts.size(), is(1));
             MultiPart.Part part = parts.get(0);
@@ -718,7 +689,7 @@ public void testPartWithBackSlashInFileName() throws Exception
     public void testPartWithWindowsFileName() throws Exception
     {
         AsyncContent source = new TestContent();
-        MultiPartFormData formData = new MultiPartFormData(source, "AaB03x");
+        MultiPartFormData.Parser formData = new MultiPartFormData.Parser("AaB03x");
         formData.setFilesDirectory(_tmpDir);
         formData.setMaxMemoryFileSize(-1);
 
@@ -731,9 +702,7 @@ public void testPartWithWindowsFileName() throws Exception
             --AaB03x--\r
             """;
         Content.Sink.write(source, true, contents, Callback.NOOP);
-        formData.parse();
-
-        try (MultiPartFormData.Parts parts = formData.get(5, TimeUnit.SECONDS))
+        try (MultiPartFormData.Parts parts = formData.parse(source).get(5, TimeUnit.SECONDS))
         {
             assertThat(parts.size(), is(1));
             MultiPart.Part part = parts.get(0);
@@ -748,7 +717,7 @@ public void testPartWithWindowsFileName() throws Exception
     public void testCorrectlyEncodedMSFilename() throws Exception
     {
         AsyncContent source = new TestContent();
-        MultiPartFormData formData = new MultiPartFormData(source, "AaB03x");
+        MultiPartFormData.Parser formData = new MultiPartFormData.Parser("AaB03x");
         formData.setFilesDirectory(_tmpDir);
         formData.setMaxMemoryFileSize(-1);
 
@@ -761,9 +730,7 @@ public void testCorrectlyEncodedMSFilename() throws Exception
             --AaB03x--\r
             """;
         Content.Sink.write(source, true, contents, Callback.NOOP);
-        formData.parse();
-
-        try (MultiPartFormData.Parts parts = formData.get(5, TimeUnit.SECONDS))
+        try (MultiPartFormData.Parts parts = formData.parse(source).get(5, TimeUnit.SECONDS))
         {
             assertThat(parts.size(), is(1));
             MultiPart.Part part = parts.get(0);
@@ -775,7 +742,7 @@ public void testCorrectlyEncodedMSFilename() throws Exception
     public void testWriteFilesForPartWithoutFileName() throws Exception
     {
         AsyncContent source = new TestContent();
-        MultiPartFormData formData = new MultiPartFormData(source, "AaB03x");
+        MultiPartFormData.Parser formData = new MultiPartFormData.Parser("AaB03x");
         formData.setFilesDirectory(_tmpDir);
         formData.setUseFilesForPartsWithoutFileName(true);
 
@@ -788,9 +755,7 @@ public void testWriteFilesForPartWithoutFileName() throws Exception
             --AaB03x--\r
             """;
         Content.Sink.write(source, true, body, Callback.NOOP);
-        formData.parse();
-
-        try (MultiPartFormData.Parts parts = formData.get(5, TimeUnit.SECONDS))
+        try (MultiPartFormData.Parts parts = formData.parse(source).get(5, TimeUnit.SECONDS))
         {
             assertThat(parts.size(), is(1));
             MultiPart.Part part = parts.get(0);
@@ -805,7 +770,7 @@ public void testWriteFilesForPartWithoutFileName() throws Exception
     public void testPartsWithSameName() throws Exception
     {
         AsyncContent source = new TestContent();
-        MultiPartFormData formData = new MultiPartFormData(source, "AaB03x");
+        MultiPartFormData.Parser formData = new MultiPartFormData.Parser("AaB03x");
         formData.setFilesDirectory(_tmpDir);
 
         String sameNames = """
@@ -822,9 +787,7 @@ public void testPartsWithSameName() throws Exception
             --AaB03x--\r
             """;
         Content.Sink.write(source, true, sameNames, Callback.NOOP);
-        formData.parse();
-
-        try (MultiPartFormData.Parts parts = formData.get(5, TimeUnit.SECONDS))
+        try (MultiPartFormData.Parts parts = formData.parse(source).get(5, TimeUnit.SECONDS))
         {
             assertEquals(2, parts.size());
 
diff --git a/jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/ContentSourceCompletableFuture.java b/jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/ContentSourceCompletableFuture.java
index 55c91c282cd9..45269588806f 100644
--- a/jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/ContentSourceCompletableFuture.java
+++ b/jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/ContentSourceCompletableFuture.java
@@ -81,7 +81,7 @@ private void onContentAvailable()
         }
     }
 
-    protected abstract X parse(Content.Chunk chunk);
+    protected abstract X parse(Content.Chunk chunk) throws Throwable;
 
     protected boolean ignoreTransientFailure(Throwable cause)
     {
diff --git a/jetty-core/jetty-server/src/main/java/org/eclipse/jetty/server/handler/DelayedHandler.java b/jetty-core/jetty-server/src/main/java/org/eclipse/jetty/server/handler/DelayedHandler.java
index b0b1bee8374e..9e14908cbb42 100644
--- a/jetty-core/jetty-server/src/main/java/org/eclipse/jetty/server/handler/DelayedHandler.java
+++ b/jetty-core/jetty-server/src/main/java/org/eclipse/jetty/server/handler/DelayedHandler.java
@@ -262,13 +262,13 @@ private void executeProcess(Fields fields, Throwable x)
 
     protected static class UntilMultiPartDelayedProcess extends DelayedProcess
     {
-        private final MultiPartFormData _formData;
+        private final MultiPartFormData.Parser _formData;
 
         public UntilMultiPartDelayedProcess(Handler handler, Request wrapped, Response response, Callback callback, String contentType)
         {
             super(handler, wrapped, response, callback);
             String boundary = MultiPart.extractBoundary(contentType);
-            _formData = boundary == null ? null : new MultiPartFormData(wrapped, boundary);
+            _formData = boundary == null ? null : new MultiPartFormData.Parser(boundary);
         }
 
         private void process(MultiPartFormData.Parts parts, Throwable x)
@@ -308,15 +308,15 @@ public void delay()
             else
             {
                 _formData.setFilesDirectory(getRequest().getContext().getTempDirectory().toPath());
-                _formData.parse();
+                CompletableFuture<MultiPartFormData.Parts> futureParts = _formData.parse(getRequest());
                 // if we are done already, then we are still in the scope of the original process call and can
                 // process directly, otherwise we must execute a call to process as we are within a serialized
                 // demand callback.
-                if (_formData.isDone())
+                if (futureParts.isDone())
                 {
                     try
                     {
-                        MultiPartFormData.Parts parts = _formData.join();
+                        MultiPartFormData.Parts parts = futureParts.join();
                         process(parts, null);
                     }
                     catch (Throwable t)
@@ -326,7 +326,7 @@ public void delay()
                 }
                 else
                 {
-                    _formData.whenComplete(this::executeProcess);
+                    futureParts.whenComplete(this::executeProcess);
                 }
             }
         }
diff --git a/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/handler/MultiPartFormDataHandlerTest.java b/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/handler/MultiPartFormDataHandlerTest.java
index 20ee9dc0602e..0d1e657b76ba 100644
--- a/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/handler/MultiPartFormDataHandlerTest.java
+++ b/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/handler/MultiPartFormDataHandlerTest.java
@@ -79,7 +79,8 @@ public void testSimpleMultiPart() throws Exception
             public boolean handle(Request request, Response response, Callback callback)
             {
                 String boundary = MultiPart.extractBoundary(request.getHeaders().get(HttpHeader.CONTENT_TYPE));
-                new MultiPartFormData(request, boundary).parse()
+                new MultiPartFormData.Parser(boundary)
+                    .parse(request)
                     .whenComplete((parts, failure) ->
                     {
                         if (parts != null)
@@ -193,13 +194,15 @@ public void testEchoMultiPart() throws Exception
             public boolean handle(Request request, Response response, Callback callback)
             {
                 String boundary = MultiPart.extractBoundary(request.getHeaders().get(HttpHeader.CONTENT_TYPE));
-                new MultiPartFormData(request, boundary).parse()
+
+                new MultiPartFormData.Parser(boundary)
+                    .parse(request)
                     .whenComplete((parts, failure) ->
                     {
                         if (parts != null)
                         {
-                            response.getHeaders().put(HttpHeader.CONTENT_TYPE, "multipart/form-data; boundary=\"%s\"".formatted(parts.getMultiPartFormData().getBoundary()));
-                            MultiPartFormData.ContentSource source = new MultiPartFormData.ContentSource(parts.getMultiPartFormData().getBoundary());
+                            response.getHeaders().put(HttpHeader.CONTENT_TYPE, "multipart/form-data; boundary=\"%s\"".formatted(boundary));
+                            MultiPartFormData.ContentSource source = new MultiPartFormData.ContentSource(boundary);
                             source.setPartHeadersMaxLength(1024);
                             parts.forEach(source::addPart);
                             source.close();
@@ -311,22 +314,21 @@ public boolean handle(Request request, Response response, Callback callback)
             assertNotNull(boundary);
 
             ByteBufferContentSource byteBufferContentSource = new ByteBufferContentSource(ByteBuffer.wrap(response.getContentBytes()));
-            MultiPartFormData formData = new MultiPartFormData(byteBufferContentSource, boundary);
+            MultiPartFormData.Parser formData = new MultiPartFormData.Parser(boundary);
             formData.setFilesDirectory(tempDir);
-            formData.parse();
-            MultiPartFormData.Parts parts = formData.join();
-
-            assertEquals(2, parts.size());
-            MultiPart.Part part1 = parts.get(0);
-            assertEquals("part1", part1.getName());
-            assertEquals("hello", part1.getContentAsString(UTF_8));
-            MultiPart.Part part2 = parts.get(1);
-            assertEquals("part2", part2.getName());
-            assertEquals("file2.bin", part2.getFileName());
-            HttpFields headers2 = part2.getHeaders();
-            assertEquals(2, headers2.size());
-            assertEquals("application/octet-stream", headers2.get(HttpHeader.CONTENT_TYPE));
-            assertEquals(32, part2.getContentSource().getLength());
+            try (MultiPartFormData.Parts parts = formData.parse(byteBufferContentSource).join())
+            {
+                assertEquals(2, parts.size());
+                MultiPart.Part part1 = parts.get(0);
+                assertEquals("part1", part1.getName());
+                assertEquals("hello", part1.getContentAsString(UTF_8));
+                MultiPart.Part part2 = parts.get(1);
+                assertEquals("part2", part2.getName());
+                assertEquals("file2.bin", part2.getFileName());
+                HttpFields headers2 = part2.getHeaders();
+                assertEquals(2, headers2.size());
+                assertEquals("application/octet-stream", headers2.get(HttpHeader.CONTENT_TYPE));
+            }
         }
     }
 }
diff --git a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletMultiPartFormData.java b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletMultiPartFormData.java
index e5fb376388cf..aa36d2bf10ee 100644
--- a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletMultiPartFormData.java
+++ b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletMultiPartFormData.java
@@ -16,6 +16,7 @@
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
+import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.Collection;
@@ -78,9 +79,9 @@ public static Parts from(ServletApiRequest request, int maxParts) throws IOExcep
             // Look for a previously read and parsed MultiPartFormData from the DelayedHandler.
             MultiPartFormData.Parts parts = (MultiPartFormData.Parts)request.getAttribute(MultiPartFormData.Parts.class.getName());
             if (parts != null)
-                return new Parts(parts);
+                // TODO set the files directory
+                return new Parts(null, parts);
 
-            // TODO set the files directory
             return new ServletMultiPartFormData().parse(request, maxParts);
         }
         catch (Throwable x)
@@ -110,7 +111,7 @@ private Parts parse(ServletApiRequest request, int maxParts) throws IOException
         int bufferSize = connection instanceof AbstractConnection c ? c.getInputBufferSize() : 2048;
         InputStreamContentSource input = new InputStreamContentSource(request.getInputStream(), byteBufferPool);
         input.setBufferSize(bufferSize);
-        MultiPartFormData formData = new MultiPartFormData(input, boundary);
+        MultiPartFormData.Parser formData = new MultiPartFormData.Parser(boundary);
         formData.setMaxParts(maxParts);
 
         File tmpDirFile = (File)request.getServletContext().getAttribute(ServletContext.TEMPDIR);
@@ -126,9 +127,7 @@ private Parts parse(ServletApiRequest request, int maxParts) throws IOException
         formData.setMaxLength(config.getMaxRequestSize());
         formData.setPartHeadersMaxLength(connectionMetaData.getHttpConfiguration().getRequestHeaderSize());
 
-        formData.parse();
-
-        Parts parts = new Parts(formData.join());
+        Parts parts = new Parts(formData.getFilesDirectory(), formData.parse(input).join());
         request.setAttribute(Parts.class.getName(), parts);
         return parts;
     }
@@ -140,9 +139,9 @@ public static class Parts
     {
         private final List<Part> parts = new ArrayList<>();
 
-        public Parts(MultiPartFormData.Parts parts)
+        public Parts(Path directory, MultiPartFormData.Parts parts)
         {
-            parts.forEach(part -> this.parts.add(new ServletPart(parts.getMultiPartFormData(), part)));
+            parts.forEach(part -> this.parts.add(new ServletPart(directory, part)));
         }
 
         public Part getPart(String name)
@@ -161,12 +160,12 @@ public Collection<Part> getParts()
 
     private static class ServletPart implements Part
     {
-        private final MultiPartFormData _formData;
+        private final Path _directory;
         private final MultiPart.Part _part;
 
-        private ServletPart(MultiPartFormData formData, MultiPart.Part part)
+        private ServletPart(Path directory, MultiPart.Part part)
         {
-            _formData = formData;
+            _directory = directory;
             _part = part;
         }
 
@@ -204,8 +203,8 @@ public long getSize()
         public void write(String fileName) throws IOException
         {
             Path filePath = Path.of(fileName);
-            if (!filePath.isAbsolute())
-                filePath = _formData.getFilesDirectory().resolve(filePath).normalize();
+            if (!filePath.isAbsolute() && Files.isDirectory(_directory))
+                filePath = _directory.resolve(filePath).normalize();
             _part.writeTo(filePath);
         }
 
diff --git a/jetty-ee10/jetty-ee10-servlet/src/test/java/org/eclipse/jetty/ee10/servlet/MultiPartServletTest.java b/jetty-ee10/jetty-ee10-servlet/src/test/java/org/eclipse/jetty/ee10/servlet/MultiPartServletTest.java
index e89db59f54e6..7ebbf2cdbe07 100644
--- a/jetty-ee10/jetty-ee10-servlet/src/test/java/org/eclipse/jetty/ee10/servlet/MultiPartServletTest.java
+++ b/jetty-ee10/jetty-ee10-servlet/src/test/java/org/eclipse/jetty/ee10/servlet/MultiPartServletTest.java
@@ -409,10 +409,9 @@ protected void service(HttpServletRequest request, HttpServletResponse response)
         String contentType = headers.get(HttpHeader.CONTENT_TYPE);
         String boundary = MultiPart.extractBoundary(contentType);
         InputStream inputStream = new GZIPInputStream(responseStream.getInputStream());
-        MultiPartFormData formData = new MultiPartFormData(new InputStreamContentSource(inputStream), boundary);
+        MultiPartFormData.Parser formData = new MultiPartFormData.Parser(boundary);
         formData.setMaxParts(1);
-        formData.parse();
-        MultiPartFormData.Parts parts = formData.join();
+        MultiPartFormData.Parts parts = formData.parse(new InputStreamContentSource(inputStream)).join();
 
         assertThat(parts.size(), is(1));
         assertThat(parts.get(0).getContentAsString(UTF_8), is(contentString));

From 0067bf1e8412240b2ae910b0c068ee31ff8220ea Mon Sep 17 00:00:00 2001
From: gregw <gregw@webtide.com>
Date: Thu, 29 Jun 2023 00:13:45 +0200
Subject: [PATCH 06/19] Experiment with a fully async
 ContentSourceCompletableFuture

Updates from review
---
 .../jetty/docs/programming/ContentDocs.java   | 74 +++++++++++++++++++
 .../eclipse/jetty/http/MultiPartFormData.java |  6 +-
 .../jetty/http/MultiPartFormDataTest.java     |  8 +-
 .../jetty/io/content/AsyncContent.java        |  2 +-
 4 files changed, 84 insertions(+), 6 deletions(-)

diff --git a/documentation/jetty-documentation/src/main/java/org/eclipse/jetty/docs/programming/ContentDocs.java b/documentation/jetty-documentation/src/main/java/org/eclipse/jetty/docs/programming/ContentDocs.java
index aa3364180f57..749d258a3db2 100644
--- a/documentation/jetty-documentation/src/main/java/org/eclipse/jetty/docs/programming/ContentDocs.java
+++ b/documentation/jetty-documentation/src/main/java/org/eclipse/jetty/docs/programming/ContentDocs.java
@@ -13,10 +13,15 @@
 
 package org.eclipse.jetty.docs.programming;
 
+import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
+import java.util.concurrent.CompletableFuture;
+
 import org.eclipse.jetty.io.Content;
 import org.eclipse.jetty.io.content.AsyncContent;
 import org.eclipse.jetty.util.BufferUtil;
 import org.eclipse.jetty.util.Callback;
+import org.eclipse.jetty.util.CharsetStringBuilder;
 import org.eclipse.jetty.util.FutureCallback;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -146,8 +151,77 @@ public static void testEcho() throws Exception
             throw new IllegalStateException("EOF expected");
     }
 
+    public static class FutureString extends CompletableFuture<String>
+    {
+        private final CharsetStringBuilder text;
+        private final Content.Source source;
+
+        public FutureString(Content.Source source, Charset charset)
+        {
+            this.source = source;
+            this.text = CharsetStringBuilder.forCharset(charset);
+            source.demand(this::onContentAvailable);
+        }
+
+        private void onContentAvailable()
+        {
+            while (true)
+            {
+                Content.Chunk chunk = source.read();
+                if (chunk == null)
+                {
+                    source.demand(this::onContentAvailable);
+                    return;
+                }
+
+                try
+                {
+                    if (Content.Chunk.isFailure(chunk))
+                        throw chunk.getFailure();
+
+                    if (chunk.hasRemaining())
+                        text.append(chunk.getByteBuffer());
+
+                    if (chunk.isLast() && complete(text.build()))
+                        return;
+                }
+                catch (Throwable e)
+                {
+                    completeExceptionally(e);
+                }
+                finally
+                {
+                    chunk.release();
+                }
+            }
+        }
+    }
+
+    public static void testFutureString() throws Exception
+    {
+        AsyncContent source = new AsyncContent();
+        FutureString future = new FutureString(source, StandardCharsets.UTF_8);
+        if (future.isDone())
+            throw new IllegalStateException();
+
+        Callback.Completable writeCallback = new Callback.Completable();
+        Content.Sink.write(source, false, "One", writeCallback);
+        if (!writeCallback.isDone() || future.isDone())
+            throw new IllegalStateException("Should be consumed");
+        Content.Sink.write(source, false, "Two", writeCallback);
+        if (!writeCallback.isDone() || future.isDone())
+            throw new IllegalStateException("Should be consumed");
+        Content.Sink.write(source, true, "Three", writeCallback);
+        if (!writeCallback.isDone() || !future.isDone())
+            throw new IllegalStateException("Should be consumed");
+
+        System.err.println(future.get());
+
+    }
+
     public static void main(String... args) throws Exception
     {
         testEcho();
+        testFutureString();
     }
 }
diff --git a/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartFormData.java b/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartFormData.java
index 8c03c96e08d9..0fb2e109fc94 100644
--- a/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartFormData.java
+++ b/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartFormData.java
@@ -221,8 +221,10 @@ protected Parts parse(Content.Chunk chunk) throws Throwable
                 @Override
                 public boolean completeExceptionally(Throwable failure)
                 {
-                    listener.fail(failure);
-                    return super.completeExceptionally(failure);
+                    boolean failed = super.completeExceptionally(failure);
+                    if (failed)
+                        listener.fail(failure);
+                    return failed;
                 }
             };
             futureParts.parse();
diff --git a/jetty-core/jetty-http/src/test/java/org/eclipse/jetty/http/MultiPartFormDataTest.java b/jetty-core/jetty-http/src/test/java/org/eclipse/jetty/http/MultiPartFormDataTest.java
index 823b90d4a1a3..5ccff5406a65 100644
--- a/jetty-core/jetty-http/src/test/java/org/eclipse/jetty/http/MultiPartFormDataTest.java
+++ b/jetty-core/jetty-http/src/test/java/org/eclipse/jetty/http/MultiPartFormDataTest.java
@@ -808,10 +808,12 @@ public void testPartsWithSameName() throws Exception
     private class TestContent extends AsyncContent
     {
         @Override
-        protected void offer(Content.Chunk chunk)
+        public Content.Chunk read()
         {
-            _allocatedChunks.add(chunk);
-            super.offer(chunk);
+            Content.Chunk chunk = super.read();
+            if (chunk != null && chunk.canRetain())
+                _allocatedChunks.add(chunk);
+            return chunk;
         }
     }
 }
diff --git a/jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/AsyncContent.java b/jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/AsyncContent.java
index 9ab80e4282cf..6bd5eeebc32a 100644
--- a/jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/AsyncContent.java
+++ b/jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/AsyncContent.java
@@ -79,7 +79,7 @@ public void write(boolean last, ByteBuffer byteBuffer, Callback callback)
      * or succeeded if and only if the chunk is terminal, as non-terminal
      * chunks have to bind the succeeding of the callback to their release.
      */
-    protected void offer(Content.Chunk chunk)
+    private void offer(Content.Chunk chunk)
     {
         Throwable failure = null;
         boolean wasEmpty = false;

From 372747378b428b824780f84cf2d787daecef5aa9 Mon Sep 17 00:00:00 2001
From: gregw <gregw@webtide.com>
Date: Thu, 29 Jun 2023 10:45:39 +0200
Subject: [PATCH 07/19] Experiment with a fully async
 ContentSourceCompletableFuture

Updated MultiPartByteRanges
---
 .../jetty/docs/programming/ContentDocs.java   |  19 ++
 .../jetty/http/MultiPartByteRanges.java       | 227 ++++++++----------
 .../ContentSourceCompletableFuture.java       |  39 +++
 .../jetty/server/MultiPartByteRangesTest.java |   5 +-
 .../ResourceHandlerByteRangesTest.java        |   2 +-
 5 files changed, 162 insertions(+), 130 deletions(-)

diff --git a/documentation/jetty-documentation/src/main/java/org/eclipse/jetty/docs/programming/ContentDocs.java b/documentation/jetty-documentation/src/main/java/org/eclipse/jetty/docs/programming/ContentDocs.java
index 749d258a3db2..959767fb7882 100644
--- a/documentation/jetty-documentation/src/main/java/org/eclipse/jetty/docs/programming/ContentDocs.java
+++ b/documentation/jetty-documentation/src/main/java/org/eclipse/jetty/docs/programming/ContentDocs.java
@@ -19,10 +19,12 @@
 
 import org.eclipse.jetty.io.Content;
 import org.eclipse.jetty.io.content.AsyncContent;
+import org.eclipse.jetty.io.content.ContentSourceCompletableFuture;
 import org.eclipse.jetty.util.BufferUtil;
 import org.eclipse.jetty.util.Callback;
 import org.eclipse.jetty.util.CharsetStringBuilder;
 import org.eclipse.jetty.util.FutureCallback;
+import org.eclipse.jetty.util.Utf8StringBuilder;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -216,7 +218,24 @@ public static void testFutureString() throws Exception
             throw new IllegalStateException("Should be consumed");
 
         System.err.println(future.get());
+    }
+
+    public static class FutureUtf8String extends ContentSourceCompletableFuture<String>
+    {
+        Utf8StringBuilder builder = new Utf8StringBuilder();
+
+        public FutureUtf8String(Content.Source content)
+        {
+            super(content);
+        }
 
+        @Override
+        protected String parse(Content.Chunk chunk) throws Throwable
+        {
+            if (chunk.hasRemaining())
+                builder.append(chunk.getByteBuffer());
+            return chunk.isLast() ? builder.takeCompleteString(IllegalStateException::new) : null;
+        }
     }
 
     public static void main(String... args) throws Exception
diff --git a/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartByteRanges.java b/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartByteRanges.java
index 57c89a18bb48..b4c8fd3f74de 100644
--- a/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartByteRanges.java
+++ b/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartByteRanges.java
@@ -13,7 +13,6 @@
 
 package org.eclipse.jetty.http;
 
-import java.io.EOFException;
 import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.nio.channels.SeekableByteChannel;
@@ -24,12 +23,12 @@
 import java.util.concurrent.CompletableFuture;
 
 import org.eclipse.jetty.io.Content;
+import org.eclipse.jetty.io.content.ContentSourceCompletableFuture;
 import org.eclipse.jetty.util.thread.AutoLock;
 
 /**
  * <p>A {@link CompletableFuture} that is completed when a multipart/byteranges
- * content has been parsed asynchronously from a {@link Content.Source} via
- * {@link #parse(Content.Source)}.</p>
+ * has been parsed asynchronously from a {@link Content.Source}.</p>
  * <p>Once the parsing of the multipart/byteranges content completes successfully,
  * objects of this class are completed with a {@link MultiPartByteRanges.Parts}
  * object.</p>
@@ -55,79 +54,8 @@
  */
 public class MultiPartByteRanges extends CompletableFuture<MultiPartByteRanges.Parts>
 {
-    // TODO base the implementation on a ContentSourceCompletableFuture
-    private final PartsListener listener = new PartsListener();
-    private final MultiPart.Parser parser;
-
-    public MultiPartByteRanges(String boundary)
-    {
-        this.parser = new MultiPart.Parser(boundary, listener);
-    }
-
-    /**
-     * @return the boundary string
-     */
-    public String getBoundary()
+    private MultiPartByteRanges()
     {
-        return parser.getBoundary();
-    }
-
-    @Override
-    public boolean completeExceptionally(Throwable failure)
-    {
-        listener.fail(failure);
-        return super.completeExceptionally(failure);
-    }
-
-    /**
-     * <p>Parses the given multipart/byteranges content.</p>
-     * <p>Returns this {@code MultiPartByteRanges} object,
-     * so that it can be used in the typical "fluent" style
-     * of {@link CompletableFuture}.</p>
-     *
-     * @param content the multipart/byteranges content to parse
-     * @return this {@code MultiPartByteRanges} object
-     */
-    public MultiPartByteRanges parse(Content.Source content)
-    {
-        new Runnable()
-        {
-            @Override
-            public void run()
-            {
-                while (true)
-                {
-                    Content.Chunk chunk = content.read();
-                    if (chunk == null)
-                    {
-                        content.demand(this);
-                        return;
-                    }
-                    if (Content.Chunk.isFailure(chunk))
-                    {
-                        listener.onFailure(chunk.getFailure());
-                        return;
-                    }
-                    parse(chunk);
-                    chunk.release();
-                    if (isDone())
-                        return;
-                    if (chunk.isLast())
-                    {
-                        listener.onFailure(new EOFException());
-                        return;
-                    }
-                }
-            }
-        }.run();
-        return this;
-    }
-
-    private void parse(Content.Chunk chunk)
-    {
-        if (listener.isFailed())
-            return;
-        parser.parse(chunk);
     }
 
     /**
@@ -274,76 +202,123 @@ public Content.Source newContentSource()
         }
     }
 
-    private class PartsListener extends MultiPart.AbstractPartsListener
+    public static class Parser
     {
-        private final AutoLock lock = new AutoLock();
-        private final List<Content.Chunk> partChunks = new ArrayList<>();
-        private final List<MultiPart.Part> parts = new ArrayList<>();
-        private Throwable failure;
+        private final PartsListener listener = new PartsListener();
+        private final MultiPart.Parser parser;
+        private Parts parts;
 
-        private boolean isFailed()
+        public Parser(String boundary)
         {
-            try (AutoLock ignored = lock.lock())
-            {
-                return failure != null;
-            }
+            parser = new MultiPart.Parser(boundary, listener);
         }
 
-        @Override
-        public void onPartContent(Content.Chunk chunk)
+        public CompletableFuture<MultiPartByteRanges.Parts> parse(Content.Source content)
         {
-            try (AutoLock ignored = lock.lock())
+            ContentSourceCompletableFuture<MultiPartByteRanges.Parts> futureParts = new ContentSourceCompletableFuture<>(content)
             {
-                // Retain the chunk because it is stored for later use.
-                chunk.retain();
-                partChunks.add(chunk);
-            }
+                @Override
+                protected MultiPartByteRanges.Parts parse(Content.Chunk chunk) throws Throwable
+                {
+                    if (listener.isFailed())
+                        throw listener.failure;
+                    parser.parse(chunk);
+                    if (listener.isFailed())
+                        throw listener.failure;
+                    return parts;
+                }
+
+                @Override
+                public boolean completeExceptionally(Throwable failure)
+                {
+                    boolean failed = super.completeExceptionally(failure);
+                    if (failed)
+                        listener.fail(failure);
+                    return failed;
+                }
+            };
+            futureParts.parse();
+            return futureParts;
         }
 
-        @Override
-        public void onPart(String name, String fileName, HttpFields headers)
+        /**
+         * @return the boundary string
+         */
+        public String getBoundary()
         {
-            try (AutoLock ignored = lock.lock())
-            {
-                parts.add(new MultiPart.ChunksPart(name, fileName, headers, List.copyOf(partChunks)));
-                partChunks.forEach(Content.Chunk::release);
-                partChunks.clear();
-            }
+            return parser.getBoundary();
         }
 
-        @Override
-        public void onComplete()
+        private class PartsListener extends MultiPart.AbstractPartsListener
         {
-            super.onComplete();
-            List<MultiPart.Part> copy;
-            try (AutoLock ignored = lock.lock())
+            private final AutoLock lock = new AutoLock();
+            private final List<Content.Chunk> partChunks = new ArrayList<>();
+            private final List<MultiPart.Part> parts = new ArrayList<>();
+            private Throwable failure;
+
+            private boolean isFailed()
             {
-                copy = List.copyOf(parts);
+                try (AutoLock ignored = lock.lock())
+                {
+                    return failure != null;
+                }
             }
-            complete(new Parts(getBoundary(), copy));
-        }
 
-        @Override
-        public void onFailure(Throwable failure)
-        {
-            super.onFailure(failure);
-            completeExceptionally(failure);
-        }
+            @Override
+            public void onPartContent(Content.Chunk chunk)
+            {
+                try (AutoLock ignored = lock.lock())
+                {
+                    // Retain the chunk because it is stored for later use.
+                    chunk.retain();
+                    partChunks.add(chunk);
+                }
+            }
 
-        private void fail(Throwable cause)
-        {
-            List<MultiPart.Part> partsToFail;
-            try (AutoLock ignored = lock.lock())
+            @Override
+            public void onPart(String name, String fileName, HttpFields headers)
+            {
+                try (AutoLock ignored = lock.lock())
+                {
+                    parts.add(new MultiPart.ChunksPart(name, fileName, headers, List.copyOf(partChunks)));
+                    partChunks.forEach(Content.Chunk::release);
+                    partChunks.clear();
+                }
+            }
+
+            @Override
+            public void onComplete()
             {
-                if (failure != null)
-                    return;
-                failure = cause;
-                partsToFail = List.copyOf(parts);
-                parts.clear();
-                partChunks.forEach(Content.Chunk::release);
-                partChunks.clear();
+                super.onComplete();
+                List<MultiPart.Part> copy;
+                try (AutoLock ignored = lock.lock())
+                {
+                    copy = List.copyOf(parts);
+                    Parser.this.parts = new Parts(getBoundary(), copy);
+                }
+            }
+
+            @Override
+            public void onFailure(Throwable failure)
+            {
+                fail(failure);
+            }
+
+            private void fail(Throwable cause)
+            {
+                List<MultiPart.Part> partsToFail;
+                try (AutoLock ignored = lock.lock())
+                {
+                    if (failure != null)
+                        return;
+                    failure = cause;
+                    partsToFail = List.copyOf(parts);
+                    parts.clear();
+                    partChunks.forEach(Content.Chunk::release);
+                    partChunks.clear();
+                }
+                partsToFail.forEach(p -> p.fail(cause));
             }
-            partsToFail.forEach(p -> p.fail(cause));
         }
     }
 }
diff --git a/jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/ContentSourceCompletableFuture.java b/jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/ContentSourceCompletableFuture.java
index 45269588806f..3f64d3db72db 100644
--- a/jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/ContentSourceCompletableFuture.java
+++ b/jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/ContentSourceCompletableFuture.java
@@ -19,7 +19,33 @@
 import org.eclipse.jetty.io.Content;
 
 /**
+ * A utility class to convert content from a {@link Content.Source} to an instance
+ * available via a {@link CompletableFuture}.
+ * <p>
+ * An example usage to asynchronously read UTF-8 content is:
+ * </p>
+ * <pre>
+ *     public static class FutureUtf8String extends ContentSourceCompletableFuture<String>
+ *     {
+ *         Utf8StringBuilder builder = new Utf8StringBuilder();
  *
+ *         public FutureUtf8String(Content.Source content)
+ *         {
+ *             super(content);
+ *         }
+ *
+ *         protected String parse(Content.Chunk chunk) throws Throwable
+ *         {
+ *             if (chunk.hasRemaining())
+ *                 builder.append(chunk.getByteBuffer());
+ *             return chunk.isLast() ? builder.takeCompleteString(IllegalStateException::new) : null;
+ *         }
+ *     }
+ *     ...
+ *     {
+ *         new FutureUtf8String(source).thenAccept(System.err::println);
+ *     }
+ * </pre>
  */
 public abstract class ContentSourceCompletableFuture<X> extends CompletableFuture<X>
 {
@@ -81,8 +107,21 @@ private void onContentAvailable()
         }
     }
 
+    /**
+     * Called to parse a {@link org.eclipse.jetty.io.Content.Chunk}
+     * @param chunk The chunk containing content to parse. The chunk will
+     * never be a
+     * {@link org.eclipse.jetty.io.Content.Chunk#isFailure(Content.Chunk) failure chunk}.
+     * @return The parsed {@code X} instance or null if parsing is not yet complete
+     * @throws Throwable Thrown if there is an error parsing
+     */
     protected abstract X parse(Content.Chunk chunk) throws Throwable;
 
+    /**
+     * @param cause A {@link Content.Chunk#isLast() non-last}
+     *             {@link org.eclipse.jetty.io.Content.Chunk#isFailure(Content.Chunk) failure chunk}
+     * @return True if the chunk can be ignored.
+     */
     protected boolean ignoreTransientFailure(Throwable cause)
     {
         return false;
diff --git a/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/MultiPartByteRangesTest.java b/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/MultiPartByteRangesTest.java
index 6e787edc799e..745de4c3adae 100644
--- a/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/MultiPartByteRangesTest.java
+++ b/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/MultiPartByteRangesTest.java
@@ -119,9 +119,8 @@ public boolean handle(Request request, Response response, Callback callback)
             assertNotNull(contentType);
 
             String boundary = MultiPart.extractBoundary(contentType);
-            MultiPartByteRanges byteRanges = new MultiPartByteRanges(boundary);
-            byteRanges.parse(new ByteBufferContentSource(ByteBuffer.wrap(response.getContentBytes())));
-            MultiPartByteRanges.Parts parts = byteRanges.join();
+            MultiPartByteRanges.Parser byteRanges = new MultiPartByteRanges.Parser(boundary);
+            MultiPartByteRanges.Parts parts = byteRanges.parse(new ByteBufferContentSource(ByteBuffer.wrap(response.getContentBytes()))).join();
 
             assertEquals(3, parts.size());
             MultiPart.Part part1 = parts.get(0);
diff --git a/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/handler/ResourceHandlerByteRangesTest.java b/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/handler/ResourceHandlerByteRangesTest.java
index f335ace1f6ec..70b07e1f5fcb 100644
--- a/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/handler/ResourceHandlerByteRangesTest.java
+++ b/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/handler/ResourceHandlerByteRangesTest.java
@@ -175,7 +175,7 @@ private void testTwoRanges(HttpHeader requestRangeHeader, String responseContent
             String contentType = response.get(HttpHeader.CONTENT_TYPE);
             assertThat(contentType, startsWith(responseContentType));
             String boundary = MultiPart.extractBoundary(contentType);
-            MultiPartByteRanges.Parts parts = new MultiPartByteRanges(boundary)
+            MultiPartByteRanges.Parts parts = new MultiPartByteRanges.Parser(boundary)
                 .parse(new ByteBufferContentSource(response.getContentByteBuffer()))
                 .join();
             assertEquals(2, parts.size());

From bc7bd3963ba18dab8827f5904b32f0711e1849bd Mon Sep 17 00:00:00 2001
From: gregw <gregw@webtide.com>
Date: Thu, 29 Jun 2023 12:28:09 +0200
Subject: [PATCH 08/19] Experiment with a fully async
 ContentSourceCompletableFuture

Removed MultiPart from DelayedHandler
---
 .../jetty/server/handler/DelayedHandler.java  | 75 -------------------
 1 file changed, 75 deletions(-)

diff --git a/jetty-core/jetty-server/src/main/java/org/eclipse/jetty/server/handler/DelayedHandler.java b/jetty-core/jetty-server/src/main/java/org/eclipse/jetty/server/handler/DelayedHandler.java
index 9e14908cbb42..f8807ab07123 100644
--- a/jetty-core/jetty-server/src/main/java/org/eclipse/jetty/server/handler/DelayedHandler.java
+++ b/jetty-core/jetty-server/src/main/java/org/eclipse/jetty/server/handler/DelayedHandler.java
@@ -24,8 +24,6 @@
 import org.eclipse.jetty.http.HttpHeaderValue;
 import org.eclipse.jetty.http.HttpStatus;
 import org.eclipse.jetty.http.MimeTypes;
-import org.eclipse.jetty.http.MultiPart;
-import org.eclipse.jetty.http.MultiPartFormData;
 import org.eclipse.jetty.io.Content;
 import org.eclipse.jetty.server.FormFields;
 import org.eclipse.jetty.server.Handler;
@@ -104,7 +102,6 @@ protected DelayedProcess newDelayedProcess(boolean contentExpected, String conte
         return switch (mimeType)
         {
             case FORM_ENCODED -> new UntilFormDelayedProcess(handler, request, response, callback, contentType);
-            case MULTIPART_FORM_DATA -> new UntilMultiPartDelayedProcess(handler, request, response, callback, contentType);
             default -> new UntilContentDelayedProcess(handler, request, response, callback);
         };
     }
@@ -259,76 +256,4 @@ private void executeProcess(Fields fields, Throwable x)
                 Response.writeError(getRequest(), getResponse(), getCallback(), x);
         }
     }
-
-    protected static class UntilMultiPartDelayedProcess extends DelayedProcess
-    {
-        private final MultiPartFormData.Parser _formData;
-
-        public UntilMultiPartDelayedProcess(Handler handler, Request wrapped, Response response, Callback callback, String contentType)
-        {
-            super(handler, wrapped, response, callback);
-            String boundary = MultiPart.extractBoundary(contentType);
-            _formData = boundary == null ? null : new MultiPartFormData.Parser(boundary);
-        }
-
-        private void process(MultiPartFormData.Parts parts, Throwable x)
-        {
-            if (x == null)
-            {
-                getRequest().setAttribute(MultiPartFormData.Parts.class.getName(), parts);
-                super.process();
-            }
-            else
-            {
-                Response.writeError(getRequest(), getResponse(), getCallback(), x);
-            }
-        }
-
-        private void executeProcess(MultiPartFormData.Parts parts, Throwable x)
-        {
-            if (x == null)
-            {
-                // We must execute here as even though we have consumed all the input, we are probably
-                // invoked in a demand runnable that is serialized with any write callbacks that might be done in process
-                getRequest().getContext().execute(() -> process(parts, x));
-            }
-            else
-            {
-                Response.writeError(getRequest(), getResponse(), getCallback(), x);
-            }
-        }
-
-        @Override
-        public void delay()
-        {
-            if (_formData == null)
-            {
-                this.process();
-            }
-            else
-            {
-                _formData.setFilesDirectory(getRequest().getContext().getTempDirectory().toPath());
-                CompletableFuture<MultiPartFormData.Parts> futureParts = _formData.parse(getRequest());
-                // if we are done already, then we are still in the scope of the original process call and can
-                // process directly, otherwise we must execute a call to process as we are within a serialized
-                // demand callback.
-                if (futureParts.isDone())
-                {
-                    try
-                    {
-                        MultiPartFormData.Parts parts = futureParts.join();
-                        process(parts, null);
-                    }
-                    catch (Throwable t)
-                    {
-                        process(null, t);
-                    }
-                }
-                else
-                {
-                    futureParts.whenComplete(this::executeProcess);
-                }
-            }
-        }
-    }
 }

From 17d8bb159572ab5c5fcba2d5a869cf9329fbc12b Mon Sep 17 00:00:00 2001
From: gregw <gregw@webtide.com>
Date: Thu, 29 Jun 2023 15:14:48 +0200
Subject: [PATCH 09/19] Experiment with a fully async
 ContentSourceCompletableFuture

Improved the multipart from methods
---
 .../eclipse/jetty/http/MultiPartFormData.java |  14 ++
 .../jetty/ee10/servlet/ServletApiRequest.java | 132 ++++++++------
 .../servlet/ServletMultiPartFormData.java     | 172 +++++++++---------
 .../ee10/servlet/MultiPartServletTest.java    |   8 +-
 4 files changed, 183 insertions(+), 143 deletions(-)

diff --git a/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartFormData.java b/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartFormData.java
index 0fb2e109fc94..4bfd612aa2dc 100644
--- a/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartFormData.java
+++ b/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartFormData.java
@@ -26,9 +26,11 @@
 import java.util.List;
 import java.util.Objects;
 import java.util.concurrent.CompletableFuture;
+import java.util.function.Function;
 
 import org.eclipse.jetty.io.Content;
 import org.eclipse.jetty.io.content.ContentSourceCompletableFuture;
+import org.eclipse.jetty.util.Attributes;
 import org.eclipse.jetty.util.IO;
 import org.eclipse.jetty.util.thread.AutoLock;
 import org.slf4j.Logger;
@@ -75,6 +77,18 @@ private MultiPartFormData()
     {
     }
 
+    public static CompletableFuture<Parts> from(Attributes attributes, String boundary, Function<Parser, CompletableFuture<Parts>> parse)
+    {
+        @SuppressWarnings("unchecked")
+        CompletableFuture<Parts> futureParts = (CompletableFuture<Parts>)attributes.getAttribute(MultiPartFormData.class.getName());
+        if (futureParts == null)
+        {
+            futureParts = parse.apply(new Parser(boundary));
+            attributes.setAttribute(MultiPartFormData.class.getName(), futureParts);
+        }
+        return futureParts;
+    }
+
     /**
      * <p>An ordered list of {@link MultiPart.Part}s that can
      * be accessed by index or by name, or iterated over.</p>
diff --git a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletApiRequest.java b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletApiRequest.java
index 2ef49f5d8306..5c3bafbba532 100644
--- a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletApiRequest.java
+++ b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletApiRequest.java
@@ -34,11 +34,11 @@
 import java.util.Locale;
 import java.util.Map;
 import java.util.Set;
+import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.ExecutionException;
 
 import jakarta.servlet.AsyncContext;
 import jakarta.servlet.DispatcherType;
-import jakarta.servlet.MultipartConfigElement;
 import jakarta.servlet.RequestDispatcher;
 import jakarta.servlet.ServletConnection;
 import jakarta.servlet.ServletContext;
@@ -489,39 +489,26 @@ public Collection<Part> getParts() throws IOException, ServletException
     {
         if (_parts == null)
         {
-            String contentType = getContentType();
-            if (contentType == null || !MimeTypes.Type.MULTIPART_FORM_DATA.is(HttpField.valueParameters(contentType, null)))
-                throw new ServletException("Unsupported Content-Type [%s], expected [%s]".formatted(contentType, MimeTypes.Type.MULTIPART_FORM_DATA.asString()));
-
-            MultipartConfigElement config = (MultipartConfigElement)getAttribute(ServletContextRequest.MULTIPART_CONFIG_ELEMENT);
-            if (config == null)
-                throw new IllegalStateException("No multipart config for servlet");
-
-            ServletContextHandler contextHandler = getServletRequestInfo().getServletContext().getServletContextHandler();
-            int maxFormContentSize = contextHandler.getMaxFormContentSize();
-            int maxFormKeys = contextHandler.getMaxFormKeys();
-
-            // TODO use the following
-            config.getFileSizeThreshold();
-            config.getLocation();
-            config.getMaxFileSize();
-            config.getMaxRequestSize();
-
-            _parts = ServletMultiPartFormData.from(this, maxFormKeys);
-            Collection<Part> parts = _parts.getParts();
-
-            String formCharset = null;
-            Part charsetPart = _parts.getPart("_charset_");
-            if (charsetPart != null)
+            try
             {
-                try (InputStream is = charsetPart.getInputStream())
+                CompletableFuture<ServletMultiPartFormData.Parts> futureServletMultiPartFormData = ServletMultiPartFormData.from(this);
+
+                _parts = futureServletMultiPartFormData.get();
+
+                Collection<Part> parts = _parts.getParts();
+
+                String formCharset = null;
+                Part charsetPart = _parts.getPart("_charset_");
+                if (charsetPart != null)
                 {
-                    formCharset = IO.toString(is, StandardCharsets.UTF_8);
+                    try (InputStream is = charsetPart.getInputStream())
+                    {
+                        formCharset = IO.toString(is, StandardCharsets.UTF_8);
+                    }
                 }
-            }
 
-            /*
-            Select Charset to use for this part. (NOTE: charset behavior is for the part value only and not the part header/field names)
+                /*
+                Select Charset to use for this part. (NOTE: charset behavior is for the part value only and not the part header/field names)
                 1. Use the part specific charset as provided in that part's Content-Type header; else
                 2. Use the overall default charset. Determined by:
                     a. if part name _charset_ exists, use that part's value.
@@ -529,38 +516,60 @@ public Collection<Part> getParts() throws IOException, ServletException
                         (note, this can be either from the charset field on the request Content-Type
                         header, or from a manual call to request.setCharacterEncoding())
                     c. use utf-8.
-             */
-            Charset defaultCharset;
-            if (formCharset != null)
-                defaultCharset = Charset.forName(formCharset);
-            else if (getCharacterEncoding() != null)
-                defaultCharset = Charset.forName(getCharacterEncoding());
-            else
-                defaultCharset = StandardCharsets.UTF_8;
+                */
+                Charset defaultCharset;
+                if (formCharset != null)
+                    defaultCharset = Charset.forName(formCharset);
+                else if (getCharacterEncoding() != null)
+                    defaultCharset = Charset.forName(getCharacterEncoding());
+                else
+                    defaultCharset = StandardCharsets.UTF_8;
 
-            long formContentSize = 0;
-            for (Part p : parts)
-            {
-                if (p.getSubmittedFileName() == null)
+                long maxFormContentSize = getServletRequestInfo().getServletContext().getServletContextHandler().getMaxFormContentSize();
+
+                long formContentSize = 0;
+                for (Part p : parts)
                 {
-                    formContentSize = Math.addExact(formContentSize, p.getSize());
-                    if (maxFormContentSize >= 0 && formContentSize > maxFormContentSize)
-                        throw new IllegalStateException("Form is larger than max length " + maxFormContentSize);
+                    if (p.getSubmittedFileName() == null)
+                    {
+                        // TODO does this need to be checked again?
+                        formContentSize = Math.addExact(formContentSize, p.getSize());
+                        if (maxFormContentSize >= 0 && formContentSize > maxFormContentSize)
+                            throw new IllegalStateException("Form is larger than max length " + maxFormContentSize);
 
-                    // Servlet Spec 3.0 pg 23, parts without filename must be put into params.
-                    String charset = null;
-                    if (p.getContentType() != null)
-                        charset = MimeTypes.getCharsetFromContentType(p.getContentType());
+                        // Servlet Spec 3.0 pg 23, parts without filename must be put into params.
+                        String charset = null;
+                        if (p.getContentType() != null)
+                            charset = MimeTypes.getCharsetFromContentType(p.getContentType());
 
-                    try (InputStream is = p.getInputStream())
-                    {
-                        String content = IO.toString(is, charset == null ? defaultCharset : Charset.forName(charset));
-                        if (_contentParameters == null)
-                            _contentParameters = new Fields();
-                        _contentParameters.add(p.getName(), content);
+                        try (InputStream is = p.getInputStream())
+                        {
+                            String content = IO.toString(is, charset == null ? defaultCharset : Charset.forName(charset));
+                            if (_contentParameters == null)
+                                _contentParameters = new Fields();
+                            _contentParameters.add(p.getName(), content);
+                        }
                     }
                 }
             }
+            catch (Throwable t)
+            {
+                if (LOG.isDebugEnabled())
+                    LOG.debug("getParts", t);
+
+                Throwable cause;
+                if (t instanceof ExecutionException ee)
+                    cause = ee.getCause();
+                else if (t instanceof ServletException se)
+                    cause = se.getCause();
+                else
+                    cause = t;
+
+                if (cause instanceof IOException ioException)
+                    throw ioException;
+
+                throw new ServletException(new BadMessageException("bad multipart", cause));
+            }
         }
 
         return _parts.getParts();
@@ -873,13 +882,24 @@ else if (MimeTypes.Type.MULTIPART_FORM_DATA.is(baseType) &&
                             {
                                 getParts();
                             }
-                            catch (IOException | ServletException e)
+                            catch (IOException e)
                             {
                                 String msg = "Unable to extract content parameters";
                                 if (LOG.isDebugEnabled())
                                     LOG.debug(msg, e);
                                 throw new RuntimeIOException(msg, e);
                             }
+                            catch (ServletException e)
+                            {
+                                Throwable cause = e.getCause();
+                                if (cause instanceof BadMessageException badMessageException)
+                                    throw badMessageException;
+
+                                String msg = "Unable to extract content parameters";
+                                if (LOG.isDebugEnabled())
+                                    LOG.debug(msg, e);
+                                throw new RuntimeIOException(msg, e);
+                            }
                         }
                         else
                         {
diff --git a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletMultiPartFormData.java b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletMultiPartFormData.java
index aa36d2bf10ee..906eb5af80f2 100644
--- a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletMultiPartFormData.java
+++ b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletMultiPartFormData.java
@@ -21,11 +21,14 @@
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
+import java.util.concurrent.CompletableFuture;
 
 import jakarta.servlet.MultipartConfigElement;
-import jakarta.servlet.ServletContext;
+import jakarta.servlet.ServletRequest;
 import jakarta.servlet.http.Part;
+import org.eclipse.jetty.http.HttpField;
 import org.eclipse.jetty.http.HttpHeader;
+import org.eclipse.jetty.http.MimeTypes;
 import org.eclipse.jetty.http.MultiPart;
 import org.eclipse.jetty.http.MultiPartFormData;
 import org.eclipse.jetty.io.AbstractConnection;
@@ -34,12 +37,11 @@
 import org.eclipse.jetty.io.Content;
 import org.eclipse.jetty.io.content.InputStreamContentSource;
 import org.eclipse.jetty.server.ConnectionMetaData;
-import org.eclipse.jetty.util.IO;
 import org.eclipse.jetty.util.StringUtil;
 
 /**
  * <p>Servlet specific class for multipart content support.</p>
- * <p>Use {@link #from(ServletApiRequest)} to
+ * <p>Use {@link #from(ServletRequest)} to
  * parse multipart request content into a {@link Parts} object that can
  * be used to access Servlet {@link Part} objects.</p>
  *
@@ -48,88 +50,92 @@
 public class ServletMultiPartFormData
 {
     /**
-     * <p>Parses the request content assuming it is a multipart content,
-     * and returns a {@link Parts} objects that can be used to access
-     * individual {@link Part}s.</p>
-     *
-     * @param request the HTTP request with multipart content
-     * @return a {@link Parts} object to access the individual {@link Part}s
-     * @throws IOException if reading the request content fails
-     * @see org.eclipse.jetty.server.handler.DelayedHandler
+     * Get future {@link ServletMultiPartFormData.Parts} from a servlet request.
+     * @param servletRequest A servlet request
+     * @return A future {@link ServletMultiPartFormData.Parts}, which may have already been completed.
      */
-    public static Parts from(ServletApiRequest request) throws IOException
+    public static CompletableFuture<Parts> from(ServletRequest servletRequest)
     {
-        return from(request, ServletContextHandler.DEFAULT_MAX_FORM_KEYS);
-    }
-
-    /**
-     * <p>Parses the request content assuming it is a multipart content,
-     * and returns a {@link Parts} objects that can be used to access
-     * individual {@link Part}s.</p>
-     *
-     * @param request the HTTP request with multipart content
-     * @return a {@link Parts} object to access the individual {@link Part}s
-     * @throws IOException if reading the request content fails
-     * @see org.eclipse.jetty.server.handler.DelayedHandler
-     */
-    public static Parts from(ServletApiRequest request, int maxParts) throws IOException
-    {
-        try
-        {
-            // Look for a previously read and parsed MultiPartFormData from the DelayedHandler.
-            MultiPartFormData.Parts parts = (MultiPartFormData.Parts)request.getAttribute(MultiPartFormData.Parts.class.getName());
-            if (parts != null)
-                // TODO set the files directory
-                return new Parts(null, parts);
-
-            return new ServletMultiPartFormData().parse(request, maxParts);
-        }
-        catch (Throwable x)
-        {
-            throw IO.rethrow(x);
-        }
-    }
-
-    private Parts parse(ServletApiRequest request, int maxParts) throws IOException
-    {
-        MultipartConfigElement config = (MultipartConfigElement)request.getAttribute(ServletContextRequest.MULTIPART_CONFIG_ELEMENT);
-        if (config == null)
-            throw new IllegalStateException("No multipart configuration element");
-
-        String boundary = MultiPart.extractBoundary(request.getContentType());
-        if (boundary == null)
-            throw new IllegalStateException("No multipart boundary parameter in Content-Type");
-
-        // Store MultiPartFormData as attribute on request so it is released by the HttpChannel.
-        // TODO we should look for an already done MultiPartFormData as an attribute, so it can be
-        //      read asynchronously without blocking by something like the DelayedHandler (although
-        //      probably need an in ServletContext variant to get the configuration below.
-
-        ByteBufferPool byteBufferPool = request.getRequest().getComponents().getByteBufferPool();
-        ConnectionMetaData connectionMetaData = request.getRequest().getConnectionMetaData();
-        Connection connection = connectionMetaData.getConnection();
-        int bufferSize = connection instanceof AbstractConnection c ? c.getInputBufferSize() : 2048;
-        InputStreamContentSource input = new InputStreamContentSource(request.getInputStream(), byteBufferPool);
-        input.setBufferSize(bufferSize);
-        MultiPartFormData.Parser formData = new MultiPartFormData.Parser(boundary);
-        formData.setMaxParts(maxParts);
-
-        File tmpDirFile = (File)request.getServletContext().getAttribute(ServletContext.TEMPDIR);
-        if (tmpDirFile == null)
-            tmpDirFile = new File(System.getProperty("java.io.tmpdir"));
-        String fileLocation = config.getLocation();
-        if (!StringUtil.isBlank(fileLocation))
-            tmpDirFile = new File(fileLocation);
-
-        formData.setFilesDirectory(tmpDirFile.toPath());
-        formData.setMaxMemoryFileSize(config.getFileSizeThreshold());
-        formData.setMaxFileSize(config.getMaxFileSize());
-        formData.setMaxLength(config.getMaxRequestSize());
-        formData.setPartHeadersMaxLength(connectionMetaData.getHttpConfiguration().getRequestHeaderSize());
-
-        Parts parts = new Parts(formData.getFilesDirectory(), formData.parse(input).join());
-        request.setAttribute(Parts.class.getName(), parts);
-        return parts;
+        // Look for an existing future (we use the future here rather than the parts as it can remember any failure).
+        @SuppressWarnings("unchecked")
+        CompletableFuture<Parts> futureServletParts = (CompletableFuture<Parts>)servletRequest.getAttribute(ServletMultiPartFormData.class.getName());
+        if (futureServletParts == null)
+        {
+            // No existing parts, so we need to try to read them ourselves
+
+            // Is this servlet a valid target for Multipart?
+            MultipartConfigElement config = (MultipartConfigElement)servletRequest.getAttribute(ServletContextRequest.MULTIPART_CONFIG_ELEMENT);
+            if (config == null)
+                return CompletableFuture.failedFuture(new IllegalStateException("No multipart configuration element"));
+
+            // Are we the right content type to produce our own parts?
+            String contentType = servletRequest.getContentType();
+            if (contentType == null || !MimeTypes.Type.MULTIPART_FORM_DATA.is(HttpField.valueParameters(contentType, null)))
+                return CompletableFuture.failedFuture(new IllegalStateException("Not multipart Content-Type"));
+
+            // Do we have a boundary?
+            String boundary = MultiPart.extractBoundary(servletRequest.getContentType());
+            if (boundary == null)
+                return CompletableFuture.failedFuture(new IllegalStateException("No multipart boundary parameter in Content-Type"));
+
+            // Can we access the core request, needed for components (eg buffer pools, temp directory, etc.) as well
+            // as IO optimization
+            ServletContextRequest servletContextRequest = ServletContextRequest.getServletContextRequest(servletRequest);
+            if (servletContextRequest == null)
+                return CompletableFuture.failedFuture(new IllegalStateException("No core request"));
+
+            // Get a temporary directory for larger parts.
+            File filesDirectory = StringUtil.isBlank(config.getLocation())
+                ? servletContextRequest.getContext().getTempDirectory()
+                : new File(config.getLocation());
+
+            // Look for an existing future MultiPartFormData.Parts
+            CompletableFuture<MultiPartFormData.Parts> futureFormData = MultiPartFormData.from(servletContextRequest, boundary, parser ->
+            {
+                try
+                {
+                    // No existing core parts, so we need to configure the parser.
+                    ServletContextHandler contextHandler = servletContextRequest.getServletContext().getServletContextHandler();
+                    ByteBufferPool byteBufferPool = servletContextRequest.getComponents().getByteBufferPool();
+                    ConnectionMetaData connectionMetaData = servletContextRequest.getConnectionMetaData();
+                    Connection connection = connectionMetaData.getConnection();
+
+                    Content.Source source;
+                    if (servletRequest instanceof ServletApiRequest servletApiRequest)
+                    {
+                        source = servletApiRequest.getRequest();
+                    }
+                    else
+                    {
+                        int bufferSize = connection instanceof AbstractConnection c ? c.getInputBufferSize() : 2048;
+                        InputStreamContentSource iscs = new InputStreamContentSource(servletRequest.getInputStream(), byteBufferPool);
+                        iscs.setBufferSize(bufferSize);
+                        source = iscs;
+                    }
+
+                    parser.setMaxParts(contextHandler.getMaxFormKeys());
+                    parser.setFilesDirectory(filesDirectory.toPath());
+                    parser.setMaxMemoryFileSize(config.getFileSizeThreshold());
+                    parser.setMaxFileSize(config.getMaxFileSize());
+                    parser.setMaxLength(config.getMaxRequestSize());
+                    parser.setPartHeadersMaxLength(connectionMetaData.getHttpConfiguration().getRequestHeaderSize());
+
+                    // parse the core parts.
+                    return parser.parse(source);
+                }
+                catch (Throwable failure)
+                {
+                    return CompletableFuture.failedFuture(failure);
+                }
+            });
+
+            // When available, convert the core parts to servlet parts
+            futureServletParts = futureFormData.thenApply(formDataParts -> new Parts(filesDirectory.toPath(), formDataParts));
+
+            // cache the result in attributes.
+            servletRequest.setAttribute(ServletMultiPartFormData.class.getName(), futureServletParts);
+        }
+        return futureServletParts;
     }
 
     /**
diff --git a/jetty-ee10/jetty-ee10-servlet/src/test/java/org/eclipse/jetty/ee10/servlet/MultiPartServletTest.java b/jetty-ee10/jetty-ee10-servlet/src/test/java/org/eclipse/jetty/ee10/servlet/MultiPartServletTest.java
index 7ebbf2cdbe07..e08cbd599ec2 100644
--- a/jetty-ee10/jetty-ee10-servlet/src/test/java/org/eclipse/jetty/ee10/servlet/MultiPartServletTest.java
+++ b/jetty-ee10/jetty-ee10-servlet/src/test/java/org/eclipse/jetty/ee10/servlet/MultiPartServletTest.java
@@ -169,8 +169,8 @@ protected void service(HttpServletRequest req, HttpServletResponse resp) throws
 
         assert400orEof(listener, responseContent ->
         {
-        assertThat(responseContent, containsString("Unable to parse form content"));
-        assertThat(responseContent, containsString("Form is larger than max length"));
+            assertThat(responseContent, containsString("400: bad"));
+            assertThat(responseContent, containsString("Form is larger than max length"));
         });
     }
 
@@ -207,7 +207,7 @@ protected void service(HttpServletRequest req, HttpServletResponse resp) throws
 
         assert400orEof(listener, responseContent ->
         {
-        assertThat(responseContent, containsString("Unable to parse form content"));
+        assertThat(responseContent, containsString("400: bad"));
         assertThat(responseContent, containsString("Form with too many keys"));
         });
     }
@@ -360,7 +360,7 @@ protected void service(HttpServletRequest request, HttpServletResponse response)
                 .body(multiPart)
                 .send();
 
-            assertEquals(500, response.getStatus());
+            assertEquals(400, response.getStatus());
             assertThat(response.getContentAsString(), containsString("max file size exceeded"));
         }
 

From 39cfdbd5c0f1bfeefe1676f05729d8af008fb4c8 Mon Sep 17 00:00:00 2001
From: gregw <gregw@webtide.com>
Date: Thu, 29 Jun 2023 15:28:13 +0200
Subject: [PATCH 10/19] Experiment with a fully async
 ContentSourceCompletableFuture

Improved the multipart from methods
---
 .../eclipse/jetty/ee10/servlet/ServletApiRequest.java  | 10 ++++++++--
 .../jetty/ee10/servlet/ServletMultiPartFormData.java   |  2 +-
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletApiRequest.java b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletApiRequest.java
index 5c3bafbba532..03740552f2fa 100644
--- a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletApiRequest.java
+++ b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletApiRequest.java
@@ -525,14 +525,20 @@ else if (getCharacterEncoding() != null)
                 else
                     defaultCharset = StandardCharsets.UTF_8;
 
-                long maxFormContentSize = getServletRequestInfo().getServletContext().getServletContextHandler().getMaxFormContentSize();
+                // Recheck some constraints here, just in case the preloaded parts were not properly configured.
+                ServletContextHandler servletContextHandler = getServletRequestInfo().getServletContext().getServletContextHandler();
+                long maxFormContentSize = servletContextHandler.getMaxFormContentSize();
+                int maxFormKeys = servletContextHandler.getMaxFormKeys();
 
                 long formContentSize = 0;
+                int count = 0;
                 for (Part p : parts)
                 {
+                    if (maxFormKeys > 0 && ++count > maxFormKeys)
+                        throw new IllegalStateException("Too many form keys > " + maxFormKeys);
+
                     if (p.getSubmittedFileName() == null)
                     {
-                        // TODO does this need to be checked again?
                         formContentSize = Math.addExact(formContentSize, p.getSize());
                         if (maxFormContentSize >= 0 && formContentSize > maxFormContentSize)
                             throw new IllegalStateException("Form is larger than max length " + maxFormContentSize);
diff --git a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletMultiPartFormData.java b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletMultiPartFormData.java
index 906eb5af80f2..1405f06b346c 100644
--- a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletMultiPartFormData.java
+++ b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletMultiPartFormData.java
@@ -52,7 +52,7 @@ public class ServletMultiPartFormData
     /**
      * Get future {@link ServletMultiPartFormData.Parts} from a servlet request.
      * @param servletRequest A servlet request
-     * @return A future {@link ServletMultiPartFormData.Parts}, which may have already been completed.
+     * @return A future {@link ServletMultiPartFormData.Parts}, which may have already been created and/or completed.
      */
     public static CompletableFuture<Parts> from(ServletRequest servletRequest)
     {

From 1d715098ee4cef79d9686959de332416beeb50f2 Mon Sep 17 00:00:00 2001
From: gregw <gregw@webtide.com>
Date: Thu, 29 Jun 2023 18:05:19 +0200
Subject: [PATCH 11/19] Experiment with a fully async
 ContentSourceCompletableFuture

Get attribute from ServletContextRequest
---
 .../content/ContentSourceCompletableFuture.java |  3 ++-
 .../jetty/ee10/servlet/ServletApiRequest.java   |  1 +
 .../ee10/servlet/ServletContextRequest.java     |  4 ++++
 .../jetty/ee10/servlet/ServletHolder.java       | 17 +++++++----------
 .../ee10/servlet/ServletMultiPartFormData.java  |  1 +
 .../ee10/servlet/MultiPartServletTest.java      |  9 +++++----
 6 files changed, 20 insertions(+), 15 deletions(-)

diff --git a/jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/ContentSourceCompletableFuture.java b/jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/ContentSourceCompletableFuture.java
index 3f64d3db72db..c23922b852e8 100644
--- a/jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/ContentSourceCompletableFuture.java
+++ b/jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/ContentSourceCompletableFuture.java
@@ -25,7 +25,7 @@
  * An example usage to asynchronously read UTF-8 content is:
  * </p>
  * <pre>
- *     public static class FutureUtf8String extends ContentSourceCompletableFuture<String>
+ *     public static class FutureUtf8String extends ContentSourceCompletableFuture&lt;String&gt;
  *     {
  *         Utf8StringBuilder builder = new Utf8StringBuilder();
  *
@@ -34,6 +34,7 @@
  *             super(content);
  *         }
  *
+ *         &#064;Override
  *         protected String parse(Content.Chunk chunk) throws Throwable
  *         {
  *             if (chunk.hasRemaining())
diff --git a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletApiRequest.java b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletApiRequest.java
index 03740552f2fa..9dbf56b12659 100644
--- a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletApiRequest.java
+++ b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletApiRequest.java
@@ -675,6 +675,7 @@ public Object getAttribute(String name)
         if (_async != null)
         {
             // This switch works by allowing the attribute to get underneath any dispatch wrapper.
+            // Note that there are further servlet specific attributes in ServletContextRequest
             return switch (name)
             {
                 case AsyncContext.ASYNC_REQUEST_URI -> getRequestURI();
diff --git a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletContextRequest.java b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletContextRequest.java
index b09fc4106511..6b414768c97c 100644
--- a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletContextRequest.java
+++ b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletContextRequest.java
@@ -239,6 +239,8 @@ public Object getAttribute(String name)
             case "jakarta.servlet.request.key_size" -> super.getAttribute(SecureRequestCustomizer.KEY_SIZE_ATTRIBUTE);
             case "jakarta.servlet.request.ssl_session_id" -> super.getAttribute(SecureRequestCustomizer.SSL_SESSION_ID_ATTRIBUTE);
             case "jakarta.servlet.request.X509Certificate" -> super.getAttribute(SecureRequestCustomizer.PEER_CERTIFICATES_ATTRIBUTE);
+            case ServletContextRequest.MULTIPART_CONFIG_ELEMENT -> _matchedResource.getResource().getServletHolder().getMultipartConfig();
+
             default -> super.getAttribute(name);
         };
     }
@@ -255,6 +257,8 @@ public Set<String> getAttributeNameSet()
             names.add("jakarta.servlet.request.ssl_session_id");
         if (names.contains(SecureRequestCustomizer.PEER_CERTIFICATES_ATTRIBUTE))
             names.add("jakarta.servlet.request.X509Certificate");
+        if (_matchedResource.getResource().getServletHolder().getMultipartConfig() != null)
+            names.add(ServletContextRequest.MULTIPART_CONFIG_ELEMENT);
         return names;
     }
 
diff --git a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletHolder.java b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletHolder.java
index a3079dc50cc3..2404db1c6425 100644
--- a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletHolder.java
+++ b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletHolder.java
@@ -74,7 +74,7 @@ public class ServletHolder extends Holder<Servlet> implements Comparable<Servlet
     private Map<String, String> _roleMap;
     private String _forcedPath;
     private String _runAsRole;
-    private ServletRegistration.Dynamic _registration;
+    private ServletHolder.Registration _registration;
     private JspContainer _jspContainer;
 
     private volatile Servlet _servlet;
@@ -155,6 +155,11 @@ public ServletHolder(Class<? extends Servlet> servlet)
         setHeldClass(servlet);
     }
 
+    public Object getMultipartConfig()
+    {
+        return _registration == null ? null : _registration.getMultipartConfig();
+    }
+
     /**
      * @return The unavailable exception or null if not unavailable
      */
@@ -710,14 +715,6 @@ protected void prepare(ServletRequest request, ServletResponse response) throws
     {
         // Ensure the servlet is initialized prior to any filters being invoked
         getServlet();
-
-        // Check for multipart config
-        if (_registration != null)
-        {
-            MultipartConfigElement mpce = ((Registration)_registration).getMultipartConfig();
-            if (mpce != null)
-                request.setAttribute(ServletContextRequest.MULTIPART_CONFIG_ELEMENT, mpce);
-        }
     }
 
     /**
@@ -1015,7 +1012,7 @@ public Set<String> setServletSecurity(ServletSecurityElement securityElement)
         }
     }
 
-    public ServletRegistration.Dynamic getRegistration()
+    public ServletHolder.Registration getRegistration()
     {
         if (_registration == null)
             _registration = new Registration();
diff --git a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletMultiPartFormData.java b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletMultiPartFormData.java
index 1405f06b346c..a4a128d415b0 100644
--- a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletMultiPartFormData.java
+++ b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletMultiPartFormData.java
@@ -49,6 +49,7 @@
  */
 public class ServletMultiPartFormData
 {
+
     /**
      * Get future {@link ServletMultiPartFormData.Parts} from a servlet request.
      * @param servletRequest A servlet request
diff --git a/jetty-ee10/jetty-ee10-servlet/src/test/java/org/eclipse/jetty/ee10/servlet/MultiPartServletTest.java b/jetty-ee10/jetty-ee10-servlet/src/test/java/org/eclipse/jetty/ee10/servlet/MultiPartServletTest.java
index e08cbd599ec2..a460f0b5a9a7 100644
--- a/jetty-ee10/jetty-ee10-servlet/src/test/java/org/eclipse/jetty/ee10/servlet/MultiPartServletTest.java
+++ b/jetty-ee10/jetty-ee10-servlet/src/test/java/org/eclipse/jetty/ee10/servlet/MultiPartServletTest.java
@@ -108,16 +108,17 @@ private void start(HttpServlet servlet, MultipartConfigElement config, ByteBuffe
         connector = new ServerConnector(server);
         server.addConnector(connector);
 
-        ServletContextHandler contextHandler = new ServletContextHandler("/");
+        ServletContextHandler servletContextHandler = new ServletContextHandler("/");
         ServletHolder servletHolder = new ServletHolder(servlet);
         servletHolder.getRegistration().setMultipartConfig(config);
-        contextHandler.addServlet(servletHolder, "/");
+        servletContextHandler.addServlet(servletHolder, "/");
+        server.setHandler(servletContextHandler);
+
 
         GzipHandler gzipHandler = new GzipHandler();
         gzipHandler.addIncludedMimeTypes("multipart/form-data");
         gzipHandler.setMinGzipSize(32);
-        gzipHandler.setHandler(contextHandler);
-        server.setHandler(gzipHandler);
+        servletContextHandler.insertHandler(gzipHandler);
 
         server.start();
 

From 7b615e068c9d4bd24c32f087b88512828b088a34 Mon Sep 17 00:00:00 2001
From: gregw <gregw@webtide.com>
Date: Thu, 29 Jun 2023 18:40:29 +0200
Subject: [PATCH 12/19] Experiment with a fully async
 ContentSourceCompletableFuture

Fixed parts echo test
Tested with simple preload handler
---
 .../servlet/ServletMultiPartFormData.java     |   1 -
 .../ee10/servlet/MultiPartServletTest.java    | 149 ++++++++++++------
 2 files changed, 102 insertions(+), 48 deletions(-)

diff --git a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletMultiPartFormData.java b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletMultiPartFormData.java
index a4a128d415b0..1405f06b346c 100644
--- a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletMultiPartFormData.java
+++ b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletMultiPartFormData.java
@@ -49,7 +49,6 @@
  */
 public class ServletMultiPartFormData
 {
-
     /**
      * Get future {@link ServletMultiPartFormData.Parts} from a servlet request.
      * @param servletRequest A servlet request
diff --git a/jetty-ee10/jetty-ee10-servlet/src/test/java/org/eclipse/jetty/ee10/servlet/MultiPartServletTest.java b/jetty-ee10/jetty-ee10-servlet/src/test/java/org/eclipse/jetty/ee10/servlet/MultiPartServletTest.java
index a460f0b5a9a7..953bb4a98062 100644
--- a/jetty-ee10/jetty-ee10-servlet/src/test/java/org/eclipse/jetty/ee10/servlet/MultiPartServletTest.java
+++ b/jetty-ee10/jetty-ee10-servlet/src/test/java/org/eclipse/jetty/ee10/servlet/MultiPartServletTest.java
@@ -22,6 +22,7 @@
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Map;
+import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
@@ -42,26 +43,32 @@
 import org.eclipse.jetty.client.OutputStreamRequestContent;
 import org.eclipse.jetty.client.Response;
 import org.eclipse.jetty.client.StringRequestContent;
+import org.eclipse.jetty.http.HttpField;
 import org.eclipse.jetty.http.HttpFields;
 import org.eclipse.jetty.http.HttpHeader;
 import org.eclipse.jetty.http.HttpMethod;
 import org.eclipse.jetty.http.HttpScheme;
 import org.eclipse.jetty.http.HttpStatus;
 import org.eclipse.jetty.http.HttpTester;
+import org.eclipse.jetty.http.MimeTypes;
 import org.eclipse.jetty.http.MultiPart;
 import org.eclipse.jetty.http.MultiPartFormData;
-import org.eclipse.jetty.io.ByteBufferPool;
+import org.eclipse.jetty.io.Content;
 import org.eclipse.jetty.io.EofException;
 import org.eclipse.jetty.io.content.InputStreamContentSource;
 import org.eclipse.jetty.logging.StacklessLogging;
+import org.eclipse.jetty.server.Handler;
+import org.eclipse.jetty.server.Request;
 import org.eclipse.jetty.server.Server;
 import org.eclipse.jetty.server.ServerConnector;
 import org.eclipse.jetty.server.handler.gzip.GzipHandler;
+import org.eclipse.jetty.util.Callback;
 import org.eclipse.jetty.util.IO;
 import org.eclipse.jetty.util.component.LifeCycle;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
-import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
 
 import static java.nio.charset.StandardCharsets.UTF_8;
 import static org.hamcrest.MatcherAssert.assertThat;
@@ -92,19 +99,10 @@ public void before() throws Exception
         tmpDirString = tmpDir.toAbsolutePath().toString();
     }
 
-    private void start(HttpServlet servlet) throws Exception
+    private void start(HttpServlet servlet, MultipartConfigElement config, boolean preload) throws Exception
     {
-        start(servlet, new MultipartConfigElement(tmpDirString, MAX_FILE_SIZE, -1, 0));
-    }
-
-    private void start(HttpServlet servlet, MultipartConfigElement config) throws Exception
-    {
-        start(servlet, config, null);
-    }
-
-    private void start(HttpServlet servlet, MultipartConfigElement config, ByteBufferPool bufferPool) throws Exception
-    {
-        server = new Server(null, null, bufferPool);
+        config = config == null ? new MultipartConfigElement(tmpDirString, MAX_FILE_SIZE, -1, 0) : config;
+        server = new Server(null, null, null);
         connector = new ServerConnector(server);
         server.addConnector(connector);
 
@@ -114,10 +112,43 @@ private void start(HttpServlet servlet, MultipartConfigElement config, ByteBuffe
         servletContextHandler.addServlet(servletHolder, "/");
         server.setHandler(servletContextHandler);
 
-
         GzipHandler gzipHandler = new GzipHandler();
         gzipHandler.addIncludedMimeTypes("multipart/form-data");
         gzipHandler.setMinGzipSize(32);
+
+        // User a very simple preload handler
+        if (preload)
+        {
+            gzipHandler.setHandler(new Handler.Wrapper()
+            {
+                @Override
+                public boolean handle(Request request, org.eclipse.jetty.server.Response response, Callback callback) throws Exception
+                {
+                    String contentType = request.getHeaders().get(HttpHeader.CONTENT_TYPE);
+                    if (contentType == null || !MimeTypes.Type.MULTIPART_FORM_DATA.is(HttpField.valueParameters(contentType, null)))
+                        return super.handle(request, response, callback);
+
+                    CompletableFuture<ServletMultiPartFormData.Parts> futureParts = ServletMultiPartFormData.from(Request.as(request, ServletContextRequest.class).getServletApiRequest());
+                    if (futureParts.isDone())
+                        return super.handle(request, response, callback);
+
+                    futureParts.whenComplete((parts, failure) ->
+                    {
+                        try
+                        {
+                            if (!super.handle(request, response, callback))
+                                callback.failed(new IllegalStateException("Not Handled"));
+                        }
+                        catch (Throwable x)
+                        {
+                            callback.failed(x);
+                        }
+                    });
+                    return true;
+                }
+            });
+        }
+
         servletContextHandler.insertHandler(gzipHandler);
 
         server.start();
@@ -134,17 +165,18 @@ public void stop() throws Exception
         IO.delete(tmpDir.toFile());
     }
 
-    @Test
-    public void testLargePart() throws Exception
+    @ParameterizedTest
+    @ValueSource(booleans = {true, false})
+    public void testLargePart(boolean preload) throws Exception
     {
         start(new HttpServlet()
         {
             @Override
-            protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException
+            protected void service(HttpServletRequest req, HttpServletResponse resp)
             {
                 req.getParameterMap();
             }
-        }, new MultipartConfigElement(tmpDirString));
+        }, new MultipartConfigElement(tmpDirString), preload);
 
         OutputStreamRequestContent content = new OutputStreamRequestContent();
         MultiPartRequestContent multiPart = new MultiPartRequestContent();
@@ -175,8 +207,9 @@ protected void service(HttpServletRequest req, HttpServletResponse resp) throws
         });
     }
 
-    @Test
-    public void testManyParts() throws Exception
+    @ParameterizedTest
+    @ValueSource(booleans = {true, false})
+    public void testManyParts(boolean preload) throws Exception
     {
         start(new HttpServlet()
         {
@@ -185,7 +218,7 @@ protected void service(HttpServletRequest req, HttpServletResponse resp) throws
             {
                 req.getParameterMap();
             }
-        }, new MultipartConfigElement(tmpDirString));
+        }, new MultipartConfigElement(tmpDirString), preload);
 
         byte[] byteArray = new byte[1024];
         Arrays.fill(byteArray, (byte)1);
@@ -213,8 +246,9 @@ protected void service(HttpServletRequest req, HttpServletResponse resp) throws
         });
     }
 
-    @Test
-    public void testMaxRequestSize() throws Exception
+    @ParameterizedTest
+    @ValueSource(booleans = {true, false})
+    public void testMaxRequestSize(boolean preload) throws Exception
     {
         start(new HttpServlet()
         {
@@ -223,7 +257,7 @@ protected void service(HttpServletRequest req, HttpServletResponse resp) throws
             {
                 req.getParameterMap();
             }
-        }, new MultipartConfigElement(tmpDirString, -1, 1024, 1024 * 1024 * 8));
+        }, new MultipartConfigElement(tmpDirString, -1, 1024, 1024 * 1024 * 8), preload);
 
         OutputStreamRequestContent content = new OutputStreamRequestContent();
         MultiPartRequestContent multiPart = new MultiPartRequestContent();
@@ -282,13 +316,14 @@ private static void assert400orEof(InputStreamResponseListener listener, Consume
             checkbody.accept(responseContent);
     }
 
-    @Test
-    public void testSimpleMultiPart() throws Exception
+    @ParameterizedTest
+    @ValueSource(booleans = {true, false})
+    public void testSimpleMultiPart(boolean preload) throws Exception
     {
         start(new HttpServlet()
         {
             @Override
-            protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
+            protected void service(HttpServletRequest request, HttpServletResponse response1) throws ServletException, IOException
             {
                 Collection<Part> parts = request.getParts();
                 assertNotNull(parts);
@@ -298,10 +333,10 @@ protected void service(HttpServletRequest request, HttpServletResponse response)
                 Collection<String> headerNames = part.getHeaderNames();
                 assertNotNull(headerNames);
                 assertEquals(2, headerNames.size());
-                String content = IO.toString(part.getInputStream(), UTF_8);
-                assertEquals("content1", content);
+                String content1 = IO.toString(part.getInputStream(), UTF_8);
+                assertEquals("content1", content1);
             }
-        });
+        }, null, preload);
 
         try (Socket socket = new Socket("localhost", connector.getLocalPort()))
         {
@@ -333,21 +368,23 @@ protected void service(HttpServletRequest request, HttpServletResponse response)
         }
     }
 
-    @Test
-    public void testTempFilesDeletedOnError() throws Exception
+    @ParameterizedTest
+    @ValueSource(booleans = {true, false})
+    public void testTempFilesDeletedOnError(boolean preload) throws Exception
     {
         byte[] bytes = new byte[2 * MAX_FILE_SIZE];
         Arrays.fill(bytes, (byte)1);
 
+        // Should throw as the max file size is exceeded.
         start(new HttpServlet()
         {
             @Override
-            protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
+            protected void service(HttpServletRequest request, HttpServletResponse response1) throws ServletException, IOException
             {
                 // Should throw as the max file size is exceeded.
                 request.getParts();
             }
-        });
+        }, null, preload);
 
         MultiPartRequestContent multiPart = new MultiPartRequestContent();
         multiPart.addPart(new MultiPart.ContentSourcePart("largePart", "largeFile.bin", HttpFields.EMPTY, new BytesRequestContent(bytes)));
@@ -370,18 +407,34 @@ protected void service(HttpServletRequest request, HttpServletResponse response)
         assertThat(fileList.length, is(0));
     }
 
-    @Test
-    public void testMultiPartGzip() throws Exception
+    @ParameterizedTest
+    @ValueSource(booleans = {true, false})
+    public void testMultiPartGzip(boolean preload) throws Exception
     {
         start(new HttpServlet()
         {
             @Override
-            protected void service(HttpServletRequest request, HttpServletResponse response) throws IOException
+            protected void service(HttpServletRequest request, HttpServletResponse response1) throws IOException, ServletException
             {
-                response.setContentType(request.getContentType());
-                IO.copy(request.getInputStream(), response.getOutputStream());
+                String contentType1 = request.getContentType();
+                response1.setContentType(contentType1);
+                response1.flushBuffer();
+
+                MultiPartRequestContent echoParts = new MultiPartRequestContent(MultiPart.extractBoundary(contentType1));
+                Collection<Part> servletParts = request.getParts();
+                for (Part part : servletParts)
+                {
+                    HttpFields.Mutable partHeaders = HttpFields.build();
+                    for (String h1 : part.getHeaderNames())
+                        partHeaders.add(h1, part.getHeader(h1));
+
+                    echoParts.addPart(new MultiPart.ContentSourcePart(part.getName(), part.getSubmittedFileName(), partHeaders, new InputStreamContentSource(part.getInputStream())));
+                }
+                echoParts.close();
+                IO.copy(Content.Source.asInputStream(echoParts), response1.getOutputStream());
             }
-        });
+        }, null, preload);
+
         // Do not automatically handle gzip.
         client.getContentDecoderFactories().clear();
 
@@ -418,8 +471,9 @@ protected void service(HttpServletRequest request, HttpServletResponse response)
         assertThat(parts.get(0).getContentAsString(UTF_8), is(contentString));
     }
 
-    @Test
-    public void testDoubleReadFromPart() throws Exception
+    @ParameterizedTest
+    @ValueSource(booleans = {true, false})
+    public void testDoubleReadFromPart(boolean preload) throws Exception
     {
         start(new HttpServlet()
         {
@@ -433,7 +487,7 @@ protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws S
                     resp.getWriter().println("Part: name=" + part.getName() + ", size=" + part.getSize() + ", content=" + IO.toString(part.getInputStream()));
                 }
             }
-        });
+        }, null, preload);
 
         String contentString = "the quick brown fox jumps over the lazy dog, " +
             "the quick brown fox jumps over the lazy dog";
@@ -453,8 +507,9 @@ protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws S
             "Part: name=myPart, size=88, content=the quick brown fox jumps over the lazy dog, the quick brown fox jumps over the lazy dog"));
     }
 
-    @Test
-    public void testPartAsParameter() throws Exception
+    @ParameterizedTest
+    @ValueSource(booleans = {true, false})
+    public void testPartAsParameter(boolean preload) throws Exception
     {
         start(new HttpServlet()
         {
@@ -469,7 +524,7 @@ protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws S
                     resp.getWriter().println("Parameter: " + entry.getKey() + "=" + entry.getValue()[0]);
                 }
             }
-        });
+        }, null, preload);
 
         String contentString = "the quick brown fox jumps over the lazy dog, " +
             "the quick brown fox jumps over the lazy dog";

From 5eaf3d7b96989e8b6bb3b7e1836ca798f5aeb391 Mon Sep 17 00:00:00 2001
From: gregw <gregw@webtide.com>
Date: Thu, 29 Jun 2023 23:04:30 +0200
Subject: [PATCH 13/19] Experiment with a fully async
 ContentSourceCompletableFuture

removed usage of DelayedHandler
---
 .../handler/MultiPartFormDataHandlerTest.java | 69 -------------------
 1 file changed, 69 deletions(-)

diff --git a/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/handler/MultiPartFormDataHandlerTest.java b/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/handler/MultiPartFormDataHandlerTest.java
index 0d1e657b76ba..e9087a0a8ad3 100644
--- a/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/handler/MultiPartFormDataHandlerTest.java
+++ b/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/handler/MultiPartFormDataHandlerTest.java
@@ -17,8 +17,6 @@
 import java.nio.ByteBuffer;
 import java.nio.channels.SocketChannel;
 import java.nio.file.Path;
-import java.util.concurrent.CountDownLatch;
-import java.util.concurrent.TimeUnit;
 
 import org.eclipse.jetty.http.HttpField;
 import org.eclipse.jetty.http.HttpFields;
@@ -44,7 +42,6 @@
 
 import static java.nio.charset.StandardCharsets.UTF_8;
 import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
@@ -119,72 +116,6 @@ public boolean handle(Request request, Response response, Callback callback)
         }
     }
 
-    @Test
-    public void testDelayedUntilFormData() throws Exception
-    {
-        DelayedHandler delayedHandler = new DelayedHandler();
-        CountDownLatch processLatch = new CountDownLatch(1);
-        delayedHandler.setHandler(new Handler.Abstract.NonBlocking()
-        {
-            @Override
-            public boolean handle(Request request, Response response, Callback callback) throws Exception
-            {
-                processLatch.countDown();
-                MultiPartFormData.Parts parts = (MultiPartFormData.Parts)request.getAttribute(MultiPartFormData.Parts.class.getName());
-                assertNotNull(parts);
-                MultiPart.Part part = parts.get(0);
-                Content.copy(part.getContentSource(), response, callback);
-                return true;
-            }
-        });
-        start(delayedHandler);
-
-        try (SocketChannel client = SocketChannel.open(new InetSocketAddress("localhost", connector.getLocalPort())))
-        {
-            String contentBegin = """
-                --A1B2C3
-                Content-Disposition: form-data; name="part"
-                                
-                """;
-            String contentMiddle = """
-                0123456789\
-                """;
-            String contentEnd = """
-                ABCDEF
-                --A1B2C3--
-                """;
-            String header = """
-                POST / HTTP/1.1
-                Host: localhost
-                Content-Type: multipart/form-data; boundary=A1B2C3
-                Content-Length: $L
-                                
-                """.replace("$L", String.valueOf(contentBegin.length() + contentMiddle.length() + contentEnd.length()));
-
-            client.write(UTF_8.encode(header));
-            client.write(UTF_8.encode(contentBegin));
-
-            // Verify that the handler has not been called yet.
-            assertFalse(processLatch.await(1, TimeUnit.SECONDS));
-
-            client.write(UTF_8.encode(contentMiddle));
-
-            // Verify that the handler has not been called yet.
-            assertFalse(processLatch.await(1, TimeUnit.SECONDS));
-
-            // Finish to send the content.
-            client.write(UTF_8.encode(contentEnd));
-
-            // Verify that the handler has been called.
-            assertTrue(processLatch.await(5, TimeUnit.SECONDS));
-
-            HttpTester.Response response = HttpTester.parseResponse(HttpTester.from(client));
-            assertNotNull(response);
-            assertEquals(HttpStatus.OK_200, response.getStatus());
-            assertEquals("0123456789ABCDEF", response.getContent());
-        }
-    }
-
     @Test
     public void testEchoMultiPart() throws Exception
     {

From 78be33da5474262f08009fb6fb48cdc88c7250ac Mon Sep 17 00:00:00 2001
From: gregw <gregw@webtide.com>
Date: Thu, 29 Jun 2023 23:54:24 +0200
Subject: [PATCH 14/19] Experiment with a fully async
 ContentSourceCompletableFuture

ServletFormHandler
---
 .../org/eclipse/jetty/server/FormFields.java  |  6 +--
 .../ee10/servlet/ServletContextRequest.java   |  4 +-
 .../servlet/ServletMultiPartFormData.java     | 13 +++++-
 .../ee10/servlet/MultiPartServletTest.java    | 40 +------------------
 4 files changed, 19 insertions(+), 44 deletions(-)

diff --git a/jetty-core/jetty-server/src/main/java/org/eclipse/jetty/server/FormFields.java b/jetty-core/jetty-server/src/main/java/org/eclipse/jetty/server/FormFields.java
index 1f7f949add17..a0c7ea2962c0 100644
--- a/jetty-core/jetty-server/src/main/java/org/eclipse/jetty/server/FormFields.java
+++ b/jetty-core/jetty-server/src/main/java/org/eclipse/jetty/server/FormFields.java
@@ -35,6 +35,8 @@
  */
 public class FormFields extends CompletableFuture<Fields> implements Runnable
 {
+    // TODO convert to a ContentSourceCompletableFuture
+
     public static final String MAX_FIELDS_ATTRIBUTE = "org.eclipse.jetty.server.Request.maxFormKeys";
     public static final String MAX_LENGTH_ATTRIBUTE = "org.eclipse.jetty.server.Request.maxFormContentSize";
     private static final CompletableFuture<Fields> EMPTY = CompletableFuture.completedFuture(Fields.EMPTY);
@@ -59,19 +61,15 @@ public static Charset getFormEncodedCharset(Request request)
 
     public static CompletableFuture<Fields> from(Request request)
     {
-        // TODO make this attributes provided by the ContextRequest wrapper
         int maxFields = getRequestAttribute(request, FormFields.MAX_FIELDS_ATTRIBUTE);
         int maxLength = getRequestAttribute(request, FormFields.MAX_LENGTH_ATTRIBUTE);
-
         return from(request, maxFields, maxLength);
     }
 
     public static CompletableFuture<Fields> from(Request request, Charset charset)
     {
-        // TODO make this attributes provided by the ContextRequest wrapper
         int maxFields = getRequestAttribute(request, FormFields.MAX_FIELDS_ATTRIBUTE);
         int maxLength = getRequestAttribute(request, FormFields.MAX_LENGTH_ATTRIBUTE);
-
         return from(request, charset, maxFields, maxLength);
     }
 
diff --git a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletContextRequest.java b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletContextRequest.java
index 6b414768c97c..a3d53eee6297 100644
--- a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletContextRequest.java
+++ b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletContextRequest.java
@@ -32,6 +32,7 @@
 import org.eclipse.jetty.http.HttpMethod;
 import org.eclipse.jetty.http.UriCompliance;
 import org.eclipse.jetty.http.pathmap.MatchedResource;
+import org.eclipse.jetty.server.FormFields;
 import org.eclipse.jetty.server.Request;
 import org.eclipse.jetty.server.Response;
 import org.eclipse.jetty.server.SecureRequestCustomizer;
@@ -240,7 +241,8 @@ public Object getAttribute(String name)
             case "jakarta.servlet.request.ssl_session_id" -> super.getAttribute(SecureRequestCustomizer.SSL_SESSION_ID_ATTRIBUTE);
             case "jakarta.servlet.request.X509Certificate" -> super.getAttribute(SecureRequestCustomizer.PEER_CERTIFICATES_ATTRIBUTE);
             case ServletContextRequest.MULTIPART_CONFIG_ELEMENT -> _matchedResource.getResource().getServletHolder().getMultipartConfig();
-
+            case FormFields.MAX_FIELDS_ATTRIBUTE -> getServletContext().getServletContextHandler().getMaxFormKeys();
+            case FormFields.MAX_LENGTH_ATTRIBUTE -> getServletContext().getServletContextHandler().getMaxFormContentSize();
             default -> super.getAttribute(name);
         };
     }
diff --git a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletMultiPartFormData.java b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletMultiPartFormData.java
index 1405f06b346c..4d1443a9454e 100644
--- a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletMultiPartFormData.java
+++ b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletMultiPartFormData.java
@@ -53,8 +53,20 @@ public class ServletMultiPartFormData
      * Get future {@link ServletMultiPartFormData.Parts} from a servlet request.
      * @param servletRequest A servlet request
      * @return A future {@link ServletMultiPartFormData.Parts}, which may have already been created and/or completed.
+     * @see #from(ServletRequest, String)
      */
     public static CompletableFuture<Parts> from(ServletRequest servletRequest)
+    {
+        return from(servletRequest, servletRequest.getContentType());
+    }
+
+    /**
+     * Get future {@link ServletMultiPartFormData.Parts} from a servlet request.
+     * @param servletRequest A servlet request
+     * @param contentType The contentType, passed as an optimization as it has likely already been retrieved.
+     * @return A future {@link ServletMultiPartFormData.Parts}, which may have already been created and/or completed.
+     */
+    public static CompletableFuture<Parts> from(ServletRequest servletRequest, String contentType)
     {
         // Look for an existing future (we use the future here rather than the parts as it can remember any failure).
         @SuppressWarnings("unchecked")
@@ -69,7 +81,6 @@ public static CompletableFuture<Parts> from(ServletRequest servletRequest)
                 return CompletableFuture.failedFuture(new IllegalStateException("No multipart configuration element"));
 
             // Are we the right content type to produce our own parts?
-            String contentType = servletRequest.getContentType();
             if (contentType == null || !MimeTypes.Type.MULTIPART_FORM_DATA.is(HttpField.valueParameters(contentType, null)))
                 return CompletableFuture.failedFuture(new IllegalStateException("Not multipart Content-Type"));
 
diff --git a/jetty-ee10/jetty-ee10-servlet/src/test/java/org/eclipse/jetty/ee10/servlet/MultiPartServletTest.java b/jetty-ee10/jetty-ee10-servlet/src/test/java/org/eclipse/jetty/ee10/servlet/MultiPartServletTest.java
index 953bb4a98062..cace3a6aaf6a 100644
--- a/jetty-ee10/jetty-ee10-servlet/src/test/java/org/eclipse/jetty/ee10/servlet/MultiPartServletTest.java
+++ b/jetty-ee10/jetty-ee10-servlet/src/test/java/org/eclipse/jetty/ee10/servlet/MultiPartServletTest.java
@@ -22,7 +22,6 @@
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Map;
-import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
@@ -43,26 +42,21 @@
 import org.eclipse.jetty.client.OutputStreamRequestContent;
 import org.eclipse.jetty.client.Response;
 import org.eclipse.jetty.client.StringRequestContent;
-import org.eclipse.jetty.http.HttpField;
 import org.eclipse.jetty.http.HttpFields;
 import org.eclipse.jetty.http.HttpHeader;
 import org.eclipse.jetty.http.HttpMethod;
 import org.eclipse.jetty.http.HttpScheme;
 import org.eclipse.jetty.http.HttpStatus;
 import org.eclipse.jetty.http.HttpTester;
-import org.eclipse.jetty.http.MimeTypes;
 import org.eclipse.jetty.http.MultiPart;
 import org.eclipse.jetty.http.MultiPartFormData;
 import org.eclipse.jetty.io.Content;
 import org.eclipse.jetty.io.EofException;
 import org.eclipse.jetty.io.content.InputStreamContentSource;
 import org.eclipse.jetty.logging.StacklessLogging;
-import org.eclipse.jetty.server.Handler;
-import org.eclipse.jetty.server.Request;
 import org.eclipse.jetty.server.Server;
 import org.eclipse.jetty.server.ServerConnector;
 import org.eclipse.jetty.server.handler.gzip.GzipHandler;
-import org.eclipse.jetty.util.Callback;
 import org.eclipse.jetty.util.IO;
 import org.eclipse.jetty.util.component.LifeCycle;
 import org.junit.jupiter.api.AfterEach;
@@ -116,38 +110,8 @@ private void start(HttpServlet servlet, MultipartConfigElement config, boolean p
         gzipHandler.addIncludedMimeTypes("multipart/form-data");
         gzipHandler.setMinGzipSize(32);
 
-        // User a very simple preload handler
         if (preload)
-        {
-            gzipHandler.setHandler(new Handler.Wrapper()
-            {
-                @Override
-                public boolean handle(Request request, org.eclipse.jetty.server.Response response, Callback callback) throws Exception
-                {
-                    String contentType = request.getHeaders().get(HttpHeader.CONTENT_TYPE);
-                    if (contentType == null || !MimeTypes.Type.MULTIPART_FORM_DATA.is(HttpField.valueParameters(contentType, null)))
-                        return super.handle(request, response, callback);
-
-                    CompletableFuture<ServletMultiPartFormData.Parts> futureParts = ServletMultiPartFormData.from(Request.as(request, ServletContextRequest.class).getServletApiRequest());
-                    if (futureParts.isDone())
-                        return super.handle(request, response, callback);
-
-                    futureParts.whenComplete((parts, failure) ->
-                    {
-                        try
-                        {
-                            if (!super.handle(request, response, callback))
-                                callback.failed(new IllegalStateException("Not Handled"));
-                        }
-                        catch (Throwable x)
-                        {
-                            callback.failed(x);
-                        }
-                    });
-                    return true;
-                }
-            });
-        }
+            gzipHandler.setHandler(new ServletFormHandler());
 
         servletContextHandler.insertHandler(gzipHandler);
 
@@ -214,7 +178,7 @@ public void testManyParts(boolean preload) throws Exception
         start(new HttpServlet()
         {
             @Override
-            protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException
+            protected void service(HttpServletRequest req, HttpServletResponse resp)
             {
                 req.getParameterMap();
             }

From 0a739fae8f76edc8cbae76eafc7797332a527951 Mon Sep 17 00:00:00 2001
From: gregw <gregw@webtide.com>
Date: Fri, 30 Jun 2023 09:00:30 +0200
Subject: [PATCH 15/19] Experiment with a fully async
 ContentSourceCompletableFuture

Converted FormFields
---
 .../org/eclipse/jetty/server/FormFields.java  | 195 +++++++-----------
 .../eclipse/jetty/server/FormFieldsTest.java  |  86 ++++++++
 .../server/handler/gzip/GzipHandlerTest.java  |   5 +-
 .../ee10/servlet/PreloadFormHandler.java      |  87 ++++++++
 .../ee10/servlet/MultiPartServletTest.java    |   2 +-
 5 files changed, 252 insertions(+), 123 deletions(-)
 create mode 100644 jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/FormFieldsTest.java
 create mode 100644 jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/PreloadFormHandler.java

diff --git a/jetty-core/jetty-server/src/main/java/org/eclipse/jetty/server/FormFields.java b/jetty-core/jetty-server/src/main/java/org/eclipse/jetty/server/FormFields.java
index a0c7ea2962c0..19a896d5f0c0 100644
--- a/jetty-core/jetty-server/src/main/java/org/eclipse/jetty/server/FormFields.java
+++ b/jetty-core/jetty-server/src/main/java/org/eclipse/jetty/server/FormFields.java
@@ -22,6 +22,8 @@
 import org.eclipse.jetty.http.HttpHeader;
 import org.eclipse.jetty.http.MimeTypes;
 import org.eclipse.jetty.io.Content;
+import org.eclipse.jetty.io.content.ContentSourceCompletableFuture;
+import org.eclipse.jetty.util.Attributes;
 import org.eclipse.jetty.util.BufferUtil;
 import org.eclipse.jetty.util.CharsetStringBuilder;
 import org.eclipse.jetty.util.Fields;
@@ -33,10 +35,8 @@
  * A {@link CompletableFuture} that is completed once a {@code application/x-www-form-urlencoded}
  * content has been parsed asynchronously from the {@link Content.Source}.
  */
-public class FormFields extends CompletableFuture<Fields> implements Runnable
+public class FormFields extends ContentSourceCompletableFuture<Fields>
 {
-    // TODO convert to a ContentSourceCompletableFuture
-
     public static final String MAX_FIELDS_ATTRIBUTE = "org.eclipse.jetty.server.Request.maxFormKeys";
     public static final String MAX_LENGTH_ATTRIBUTE = "org.eclipse.jetty.server.Request.maxFormContentSize";
     private static final CompletableFuture<Fields> EMPTY = CompletableFuture.completedFuture(Fields.EMPTY);
@@ -88,24 +88,28 @@ public static CompletableFuture<Fields> get(Request request)
 
     public static CompletableFuture<Fields> from(Request request, int maxFields, int maxLength)
     {
-        Object attr = request.getAttribute(FormFields.class.getName());
+        return from(request, getFormEncodedCharset(request), maxFields, maxLength);
+    }
+
+    public static CompletableFuture<Fields> from(Request request, Charset charset, int maxFields, int maxLength)
+    {
+        return from(request, request, charset, maxFields, maxLength);
+    }
+
+    static CompletableFuture<Fields> from(Content.Source source, Attributes attributes, Charset charset, int maxFields, int maxLength)
+    {
+        Object attr = attributes.getAttribute(FormFields.class.getName());
         if (attr instanceof FormFields futureFormFields)
             return futureFormFields;
         else if (attr instanceof Fields fields)
             return CompletableFuture.completedFuture(fields);
 
-        Charset charset = getFormEncodedCharset(request);
         if (charset == null)
             return EMPTY;
 
-        return from(request, charset, maxFields, maxLength);
-    }
-
-    public static CompletableFuture<Fields> from(Request request, Charset charset, int maxFields, int maxLength)
-    {
-        FormFields futureFormFields = new FormFields(request, charset, maxFields, maxLength);
-        request.setAttribute(FormFields.class.getName(), futureFormFields);
-        futureFormFields.run();
+        FormFields futureFormFields = new FormFields(source, charset, maxFields, maxLength);
+        attributes.setAttribute(FormFields.class.getName(), futureFormFields);
+        futureFormFields.parse();
         return futureFormFields;
     }
 
@@ -136,6 +140,7 @@ private static int getRequestAttribute(Request request, String attribute)
 
     public FormFields(Content.Source source, Charset charset, int maxFields, int maxSize)
     {
+        super(source);
         _source = source;
         _maxFields = maxFields;
         _maxLength = maxSize;
@@ -144,137 +149,91 @@ public FormFields(Content.Source source, Charset charset, int maxFields, int max
     }
 
     @Override
-    public void run()
+    protected Fields parse(Content.Chunk chunk) throws CharacterCodingException
     {
-        Content.Chunk chunk = null;
-        try
+        String value = null;
+        ByteBuffer buffer = chunk.getByteBuffer();
+
+        do
         {
-            while (true)
+            loop:
+            while (BufferUtil.hasContent(buffer))
             {
-                chunk = _source.read();
-                if (chunk == null)
-                {
-                    _source.demand(this);
-                    return;
-                }
-
-                if (Content.Chunk.isFailure(chunk))
+                byte b = buffer.get();
+                switch (_percent)
                 {
-                    completeExceptionally(chunk.getFailure());
-                    return;
-                }
-
-                while (true)
-                {
-                    Fields.Field field = parse(chunk);
-                    if (field == null)
-                        break;
-                    if (_maxFields >= 0 && _fields.getSize() >= _maxFields)
+                    case 1 ->
                     {
-                        chunk.release();
-                        // Do not double release if completeExceptionally() throws.
-                        chunk = null;
-                        completeExceptionally(new IllegalStateException("form with too many fields"));
-                        return;
+                        _percentCode = b;
+                        _percent++;
+                        continue;
+                    }
+                    case 2 ->
+                    {
+                        _builder.append(decodeHexByte((char)_percentCode, (char)b));
+                        _percent = 0;
+                        continue;
                     }
-                    _fields.add(field);
-                }
-
-                chunk.release();
-                if (chunk.isLast())
-                {
-                    // Do not double release if complete() throws.
-                    chunk = null;
-                    complete(_fields);
-                    return;
                 }
-            }
-        }
-        catch (Throwable x)
-        {
-            if (chunk != null)
-                chunk.release();
-            completeExceptionally(x);
-        }
-    }
 
-    protected Fields.Field parse(Content.Chunk chunk) throws CharacterCodingException
-    {
-        String value = null;
-        ByteBuffer buffer = chunk.getByteBuffer();
-        loop:
-        while (BufferUtil.hasContent(buffer))
-        {
-            byte b = buffer.get();
-            switch (_percent)
-            {
-                case 1 ->
-                {
-                    _percentCode = b;
-                    _percent++;
-                    continue;
-                }
-                case 2 ->
+                if (_name == null)
                 {
-                    _builder.append(decodeHexByte((char)_percentCode, (char)b));
-                    _percent = 0;
-                    continue;
+                    switch (b)
+                    {
+                        case '=' ->
+                        {
+                            _name = _builder.build();
+                            checkLength(_name);
+                        }
+                        case '+' -> _builder.append((byte)' ');
+                        case '%' -> _percent++;
+                        default -> _builder.append(b);
+                    }
                 }
-            }
-
-            if (_name == null)
-            {
-                switch (b)
+                else
                 {
-                    case '=' ->
+                    switch (b)
                     {
-                        _name = _builder.build();
-                        checkLength(_name);
+                        case '&' ->
+                        {
+                            value = _builder.build();
+                            checkLength(value);
+                            break loop;
+                        }
+                        case '+' -> _builder.append((byte)' ');
+                        case '%' -> _percent++;
+                        default -> _builder.append(b);
                     }
-                    case '+' -> _builder.append((byte)' ');
-                    case '%' -> _percent++;
-                    default -> _builder.append(b);
                 }
             }
-            else
+
+            if (_name != null)
             {
-                switch (b)
+                if (value == null && chunk.isLast())
                 {
-                    case '&' ->
+                    if (_percent > 0)
                     {
-                        value = _builder.build();
-                        checkLength(value);
-                        break loop;
+                        _builder.append((byte)'%');
+                        _builder.append(_percentCode);
                     }
-                    case '+' -> _builder.append((byte)' ');
-                    case '%' -> _percent++;
-                    default -> _builder.append(b);
+                    value = _builder.build();
+                    checkLength(value);
                 }
-            }
-        }
 
-        if (_name != null)
-        {
-            if (value == null && chunk.isLast())
-            {
-                if (_percent > 0)
+                if (value != null)
                 {
-                    _builder.append((byte)'%');
-                    _builder.append(_percentCode);
+                    Fields.Field field = new Fields.Field(_name, value);
+                    _name = null;
+                    value = null;
+                    if (_maxFields > 0 && _fields.getSize() >= _maxFields)
+                        throw new IllegalStateException("form with too many fields > " + _maxFields);
+                    _fields.add(field);
                 }
-                value = _builder.build();
-                checkLength(value);
-            }
-
-            if (value != null)
-            {
-                Fields.Field field = new Fields.Field(_name, value);
-                _name = null;
-                return field;
             }
         }
+        while (BufferUtil.hasContent(buffer));
 
-        return null;
+        return chunk.isLast() ? _fields : null;
     }
 
     private void checkLength(String nameOrValue)
diff --git a/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/FormFieldsTest.java b/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/FormFieldsTest.java
new file mode 100644
index 000000000000..4d00dddb5efc
--- /dev/null
+++ b/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/FormFieldsTest.java
@@ -0,0 +1,86 @@
+//
+// ========================================================================
+// Copyright (c) 1995 Mort Bay Consulting Pty Ltd and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
+// which is available at https://www.apache.org/licenses/LICENSE-2.0.
+//
+// SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
+// ========================================================================
+//
+
+package org.eclipse.jetty.server;
+
+import java.nio.charset.Charset;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.CompletableFuture;
+import java.util.stream.Stream;
+
+import org.eclipse.jetty.io.content.AsyncContent;
+import org.eclipse.jetty.util.Attributes;
+import org.eclipse.jetty.util.BufferUtil;
+import org.eclipse.jetty.util.Callback;
+import org.eclipse.jetty.util.Fields;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+public class FormFieldsTest
+{
+    public static Stream<Arguments> tests()
+    {
+        return Stream.of(
+            Arguments.of(List.of("name=value"), UTF_8, -1, -1, Map.of("name", "value")),
+            Arguments.of(List.of("name=value", ""), UTF_8, -1, -1, Map.of("name", "value")),
+            Arguments.of(List.of("name", "=value", ""), UTF_8, -1, -1, Map.of("name", "value")),
+            Arguments.of(List.of("n", "ame", "=", "value"), UTF_8, -1, -1, Map.of("name", "value")),
+            Arguments.of(List.of("n=v&X=Y"), UTF_8, 2, 4, Map.of("n", "v", "X", "Y")),
+            Arguments.of(List.of("name=f¤¤&X=Y"), UTF_8, -1, -1, Map.of("name", "f¤¤", "X", "Y")),
+            Arguments.of(List.of("n=v&X=Y"), UTF_8, 1, -1, null),
+            Arguments.of(List.of("n=v&X=Y"), UTF_8, -1, 3, null)
+        );
+    }
+
+    @ParameterizedTest
+    @MethodSource("tests")
+    public void testFormFields(List<String> chunks, Charset charset, int maxFields, int maxLength, Map<String, String> expected)
+    {
+        AsyncContent source = new AsyncContent();
+        Attributes attributes = new Attributes.Mapped();
+        CompletableFuture<Fields> futureFields = FormFields.from(source, attributes, charset, maxFields, maxLength);
+        assertFalse(futureFields.isDone());
+
+        int last = chunks.size() - 1;
+        for (int i = 0; i <= last; i++)
+            source.write(i == last, BufferUtil.toBuffer(chunks.get(i), charset), Callback.NOOP);
+
+        assertTrue(futureFields.isDone());
+
+        try
+        {
+            Map<String, String> result = new HashMap<>();
+            for (Fields.Field f : futureFields.get())
+                result.put(f.getName(), f.getValue());
+
+            assertEquals(expected, result);
+        }
+        catch (AssertionError e)
+        {
+            throw e;
+        }
+        catch (Throwable e)
+        {
+            assertNull(expected);
+        }
+    }
+}
diff --git a/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/handler/gzip/GzipHandlerTest.java b/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/handler/gzip/GzipHandlerTest.java
index f7b9c918df9b..1c94cd813cb7 100644
--- a/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/handler/gzip/GzipHandlerTest.java
+++ b/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/handler/gzip/GzipHandlerTest.java
@@ -1984,11 +1984,8 @@ public static class DumpHandler extends Handler.Abstract
         public boolean handle(Request request, Response response, Callback callback) throws Exception
         {
             response.getHeaders().put(HttpHeader.CONTENT_TYPE, "text/plain");
-
             Fields queryParameters = Request.extractQueryParameters(request);
-            FormFields futureFormFields = new FormFields(request, StandardCharsets.UTF_8, -1, -1);
-            futureFormFields.run();
-            Fields formParameters = futureFormFields.get();
+            Fields formParameters = FormFields.from(request, UTF_8, -1, -1).get();
             Fields parameters = Fields.combine(queryParameters, formParameters);
 
             String dump = parameters.stream().map(f -> "%s: %s\n".formatted(f.getName(), f.getValue())).collect(Collectors.joining());
diff --git a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/PreloadFormHandler.java b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/PreloadFormHandler.java
new file mode 100644
index 000000000000..bad6553cb664
--- /dev/null
+++ b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/PreloadFormHandler.java
@@ -0,0 +1,87 @@
+//
+// ========================================================================
+// Copyright (c) 1995 Mort Bay Consulting Pty Ltd and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
+// which is available at https://www.apache.org/licenses/LICENSE-2.0.
+//
+// SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
+// ========================================================================
+//
+
+package org.eclipse.jetty.ee10.servlet;
+
+import java.util.concurrent.CompletableFuture;
+
+import jakarta.servlet.ServletRequest;
+import org.eclipse.jetty.http.HttpHeader;
+import org.eclipse.jetty.http.MimeTypes;
+import org.eclipse.jetty.server.FormFields;
+import org.eclipse.jetty.server.Handler;
+import org.eclipse.jetty.server.Request;
+import org.eclipse.jetty.util.Callback;
+
+/**
+ * Handler to asynchronously preload & parse {@link MimeTypes.Type#FORM_ENCODED} and
+ * {@link MimeTypes.Type#MULTIPART_FORM_DATA} content prior to invoking the {@link ServletHandler},
+ * which can then consume them with blocking APIs but without blocking.
+ * @see FormFields#from(Request)
+ * @see ServletMultiPartFormData#from(ServletRequest)
+ */
+public class PreloadFormHandler extends Handler.Wrapper
+{
+    public PreloadFormHandler()
+    {
+        this(null);
+    }
+
+    public PreloadFormHandler(Handler handler)
+    {
+        super(handler);
+    }
+
+    @Override
+    public boolean handle(Request request, org.eclipse.jetty.server.Response response, Callback callback) throws Exception
+    {
+        String contentType = request.getHeaders().get(HttpHeader.CONTENT_TYPE);
+        if (contentType == null)
+            return super.handle(request, response, callback);
+
+        MimeTypes.Type mimeType = MimeTypes.getBaseType(contentType);
+        if (mimeType == null)
+            return super.handle(request, response, callback);
+
+        CompletableFuture<?> future =  switch (mimeType)
+        {
+            case FORM_ENCODED -> FormFields.from(request);
+            case MULTIPART_FORM_DATA -> ServletMultiPartFormData.from(Request.as(request, ServletContextRequest.class).getServletApiRequest(), contentType);
+            default -> null;
+        };
+
+        if (future == null)
+            return super.handle(request, response, callback);
+
+        if (future.isDone())
+        {
+            if (!super.handle(request, response, callback))
+                callback.failed(new IllegalStateException("Not Handled"));
+            return true;
+        }
+
+        future.whenComplete((result, failure) ->
+        {
+            try
+            {
+                if (!super.handle(request, response, callback))
+                    callback.failed(new IllegalStateException("Not Handled"));
+            }
+            catch (Throwable x)
+            {
+                callback.failed(x);
+            }
+        });
+        return true;
+    }
+}
diff --git a/jetty-ee10/jetty-ee10-servlet/src/test/java/org/eclipse/jetty/ee10/servlet/MultiPartServletTest.java b/jetty-ee10/jetty-ee10-servlet/src/test/java/org/eclipse/jetty/ee10/servlet/MultiPartServletTest.java
index cace3a6aaf6a..4edbf4c2b86e 100644
--- a/jetty-ee10/jetty-ee10-servlet/src/test/java/org/eclipse/jetty/ee10/servlet/MultiPartServletTest.java
+++ b/jetty-ee10/jetty-ee10-servlet/src/test/java/org/eclipse/jetty/ee10/servlet/MultiPartServletTest.java
@@ -111,7 +111,7 @@ private void start(HttpServlet servlet, MultipartConfigElement config, boolean p
         gzipHandler.setMinGzipSize(32);
 
         if (preload)
-            gzipHandler.setHandler(new ServletFormHandler());
+            gzipHandler.setHandler(new PreloadFormHandler());
 
         servletContextHandler.insertHandler(gzipHandler);
 

From 91209b45bb92b1cab63ad394f92f431b8afbba49 Mon Sep 17 00:00:00 2001
From: gregw <gregw@webtide.com>
Date: Fri, 30 Jun 2023 11:54:22 +0200
Subject: [PATCH 16/19] Experiment with a fully async
 ContentSourceCompletableFuture

updates from review
---
 .../jetty/docs/programming/ContentDocs.java   |  4 +-
 .../jetty/http/MultiPartByteRanges.java       |  2 +-
 .../eclipse/jetty/http/MultiPartFormData.java |  4 +-
 .../ContentSourceCompletableFuture.java       | 42 +++++----
 .../org/eclipse/jetty/server/FormFields.java  | 91 +++++++++++++++----
 .../eclipse/jetty/server/FormFieldsTest.java  |  5 +-
 .../QuickStartGeneratorConfiguration.java     |  2 +-
 .../jetty/ee10/servlet/Dispatcher.java        |  9 ++
 ...FormHandler.java => EagerFormHandler.java} | 18 ++--
 .../ee10/servlet/ServletContextRequest.java   |  8 +-
 .../jetty/ee10/servlet/ServletHolder.java     | 12 +--
 .../ee10/servlet/MultiPartServletTest.java    | 38 ++++----
 .../webapp/StandardDescriptorProcessor.java   |  2 +-
 13 files changed, 153 insertions(+), 84 deletions(-)
 rename jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/{PreloadFormHandler.java => EagerFormHandler.java} (84%)

diff --git a/documentation/jetty-documentation/src/main/java/org/eclipse/jetty/docs/programming/ContentDocs.java b/documentation/jetty-documentation/src/main/java/org/eclipse/jetty/docs/programming/ContentDocs.java
index 959767fb7882..3724c4480f84 100644
--- a/documentation/jetty-documentation/src/main/java/org/eclipse/jetty/docs/programming/ContentDocs.java
+++ b/documentation/jetty-documentation/src/main/java/org/eclipse/jetty/docs/programming/ContentDocs.java
@@ -216,13 +216,11 @@ public static void testFutureString() throws Exception
         Content.Sink.write(source, true, "Three", writeCallback);
         if (!writeCallback.isDone() || !future.isDone())
             throw new IllegalStateException("Should be consumed");
-
-        System.err.println(future.get());
     }
 
     public static class FutureUtf8String extends ContentSourceCompletableFuture<String>
     {
-        Utf8StringBuilder builder = new Utf8StringBuilder();
+        private final Utf8StringBuilder builder = new Utf8StringBuilder();
 
         public FutureUtf8String(Content.Source content)
         {
diff --git a/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartByteRanges.java b/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartByteRanges.java
index b4c8fd3f74de..0efcc9aaf2b5 100644
--- a/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartByteRanges.java
+++ b/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartByteRanges.java
@@ -52,7 +52,7 @@
  *
  * @see Parts
  */
-public class MultiPartByteRanges extends CompletableFuture<MultiPartByteRanges.Parts>
+public class MultiPartByteRanges
 {
     private MultiPartByteRanges()
     {
diff --git a/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartFormData.java b/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartFormData.java
index 4bfd612aa2dc..1f58648e6993 100644
--- a/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartFormData.java
+++ b/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPartFormData.java
@@ -224,7 +224,7 @@ protected Parts parse(Content.Chunk chunk) throws Throwable
                         throw listener.failure;
                     length += chunk.getByteBuffer().remaining();
                     long max = getMaxLength();
-                    if (max > 0 && length > max)
+                    if (max >= 0 && length > max)
                         throw new IllegalStateException("max length exceeded: %d".formatted(max));
                     parser.parse(chunk);
                     if (listener.isFailed())
@@ -394,7 +394,7 @@ int getPartsSize()
 
         private class PartsListener extends MultiPart.AbstractPartsListener
         {
-            private final AutoLock lock = new AutoLock(); // TODO why do we need this lock?
+            private final AutoLock lock = new AutoLock();
             private final List<MultiPart.Part> parts = new ArrayList<>();
             private final List<Content.Chunk> partChunks = new ArrayList<>();
             private long fileSize;
diff --git a/jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/ContentSourceCompletableFuture.java b/jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/ContentSourceCompletableFuture.java
index c23922b852e8..ff0ef9dc7e33 100644
--- a/jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/ContentSourceCompletableFuture.java
+++ b/jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/ContentSourceCompletableFuture.java
@@ -24,8 +24,8 @@
  * <p>
  * An example usage to asynchronously read UTF-8 content is:
  * </p>
- * <pre>
- *     public static class FutureUtf8String extends ContentSourceCompletableFuture&lt;String&gt;
+ * <pre>{@code
+ *     public static class FutureUtf8String extends ContentSourceCompletableFuture<String>;
  *     {
  *         Utf8StringBuilder builder = new Utf8StringBuilder();
  *
@@ -34,7 +34,7 @@
  *             super(content);
  *         }
  *
- *         &#064;Override
+ *         @Override
  *         protected String parse(Content.Chunk chunk) throws Throwable
  *         {
  *             if (chunk.hasRemaining())
@@ -43,10 +43,8 @@
  *         }
  *     }
  *     ...
- *     {
- *         new FutureUtf8String(source).thenAccept(System.err::println);
- *     }
- * </pre>
+ *     new FutureUtf8String(source).thenAccept(System.err::println);
+ * }</pre>
  */
 public abstract class ContentSourceCompletableFuture<X> extends CompletableFuture<X>
 {
@@ -57,25 +55,27 @@ public ContentSourceCompletableFuture(Content.Source content)
         _content = content;
     }
 
-    public CompletableFuture<X> parse()
-    {
-        onContentAvailable();
-        return this;
-    }
-
-    private void onContentAvailable()
+    /**
+     * Progress the parsing, {@link Content.Source#read() reading} and/or {@link Content.Source#demand(Runnable) demanding}
+     * as necessary.
+     * <p>
+     * This method must be called once to initiate the reading and parsing,
+     * and is then called to progress parsing in response to any {@link Content.Source#demand(Runnable) demand} calls.
+     * </p>
+     */
+    public void parse()
     {
         while (true)
         {
             Content.Chunk chunk = _content.read();
             if (chunk == null)
             {
-                _content.demand(this::onContentAvailable);
+                _content.demand(this::parse);
                 return;
             }
             if (Content.Chunk.isFailure(chunk))
             {
-                if (!chunk.isLast() && ignoreTransientFailure(chunk.getFailure()))
+                if (!chunk.isLast() && onTransientFailure(chunk.getFailure()))
                     continue;
                 completeExceptionally(chunk.getFailure());
                 return;
@@ -110,9 +110,11 @@ private void onContentAvailable()
 
     /**
      * Called to parse a {@link org.eclipse.jetty.io.Content.Chunk}
-     * @param chunk The chunk containing content to parse. The chunk will
-     * never be a
-     * {@link org.eclipse.jetty.io.Content.Chunk#isFailure(Content.Chunk) failure chunk}.
+     * @param chunk The chunk containing content to parse. The chunk will never be null nor a
+     *              {@link org.eclipse.jetty.io.Content.Chunk#isFailure(Content.Chunk) failure chunk}.
+     *              If references to the content of the chunk are to be held beyond the scope of this call,
+     *              then implementations must call {@link Content.Chunk#retain()} and {@link Content.Chunk#release()}
+     *              as appropriate.
      * @return The parsed {@code X} instance or null if parsing is not yet complete
      * @throws Throwable Thrown if there is an error parsing
      */
@@ -123,7 +125,7 @@ private void onContentAvailable()
      *             {@link org.eclipse.jetty.io.Content.Chunk#isFailure(Content.Chunk) failure chunk}
      * @return True if the chunk can be ignored.
      */
-    protected boolean ignoreTransientFailure(Throwable cause)
+    protected boolean onTransientFailure(Throwable cause)
     {
         return false;
     }
diff --git a/jetty-core/jetty-server/src/main/java/org/eclipse/jetty/server/FormFields.java b/jetty-core/jetty-server/src/main/java/org/eclipse/jetty/server/FormFields.java
index 19a896d5f0c0..806b43e688b9 100644
--- a/jetty-core/jetty-server/src/main/java/org/eclipse/jetty/server/FormFields.java
+++ b/jetty-core/jetty-server/src/main/java/org/eclipse/jetty/server/FormFields.java
@@ -59,6 +59,38 @@ public static Charset getFormEncodedCharset(Request request)
         return StringUtil.isEmpty(cs) ? StandardCharsets.UTF_8 : Charset.forName(cs);
     }
 
+    /**
+     * Set a {@link Fields} or related failure for the request
+     * @param request The request to which to associate the fields with
+     * @param fields A {@link CompletableFuture} that will provide either the fields or a failure.
+     */
+    public static void set(Request request, CompletableFuture<Fields> fields)
+    {
+        request.setAttribute(FormFields.class.getName(), fields);
+    }
+
+    /**
+     * @param request The request to enquire from
+     * @return A {@link CompletableFuture} that will provide either the fields or a failure, or null if none set.
+     * @see #from(Request)
+     *
+     */
+    public static CompletableFuture<Fields> get(Request request)
+    {
+        Object attr = request.getAttribute(FormFields.class.getName());
+        if (attr instanceof FormFields futureFormFields)
+            return futureFormFields;
+        return EMPTY;
+    }
+
+    /**
+     * Find or create a {@link FormFields} from a {@link Content.Source}.
+     * @param request The {@link Request} in which to look for an existing {@link FormFields} attribute,
+     *                using the classname as the attribute name, else the request is used
+     *                as a {@link Content.Source} from which to read the fields and set the attribute.
+     * @return A {@link CompletableFuture} that will provide the {@link Fields} or a failure.
+     * @see #from(Content.Source, Attributes, Charset, int, int)
+     */
     public static CompletableFuture<Fields> from(Request request)
     {
         int maxFields = getRequestAttribute(request, FormFields.MAX_FIELDS_ATTRIBUTE);
@@ -66,6 +98,15 @@ public static CompletableFuture<Fields> from(Request request)
         return from(request, maxFields, maxLength);
     }
 
+    /**
+     * Find or create a {@link FormFields} from a {@link Content.Source}.
+     * @param request The {@link Request} in which to look for an existing {@link FormFields} attribute,
+     *                using the classname as the attribute name, else the request is used
+     *                as a {@link Content.Source} from which to read the fields and set the attribute.
+     * @param charset the {@link Charset} to use for byte to string conversion.
+     * @return A {@link CompletableFuture} that will provide the {@link Fields} or a failure.
+     * @see #from(Content.Source, Attributes, Charset, int, int)
+     */
     public static CompletableFuture<Fields> from(Request request, Charset charset)
     {
         int maxFields = getRequestAttribute(request, FormFields.MAX_FIELDS_ATTRIBUTE);
@@ -73,29 +114,47 @@ public static CompletableFuture<Fields> from(Request request, Charset charset)
         return from(request, charset, maxFields, maxLength);
     }
 
-    public static void set(Request request, CompletableFuture<Fields> fields)
-    {
-        request.setAttribute(FormFields.class.getName(), fields);
-    }
-
-    public static CompletableFuture<Fields> get(Request request)
-    {
-        Object attr = request.getAttribute(FormFields.class.getName());
-        if (attr instanceof FormFields futureFormFields)
-            return futureFormFields;
-        return EMPTY;
-    }
-
+    /**
+     * Find or create a {@link FormFields} from a {@link Content.Source}.
+     * @param request The {@link Request} in which to look for an existing {@link FormFields} attribute,
+     *                using the classname as the attribute name, else the request is used
+     *                as a {@link Content.Source} from which to read the fields and set the attribute.
+     * @param maxFields The maximum number of fields to be parsed
+     * @param maxLength The maximum total size of the fields
+     * @return A {@link CompletableFuture} that will provide the {@link Fields} or a failure.
+     * @see #from(Content.Source, Attributes, Charset, int, int)
+     */
     public static CompletableFuture<Fields> from(Request request, int maxFields, int maxLength)
     {
         return from(request, getFormEncodedCharset(request), maxFields, maxLength);
     }
 
+    /**
+     * Find or create a {@link FormFields} from a {@link Content.Source}.
+     * @param request The {@link Request} in which to look for an existing {@link FormFields} attribute,
+     *                using the classname as the attribute name, else the request is used
+     *                as a {@link Content.Source} from which to read the fields and set the attribute.
+     * @param charset the {@link Charset} to use for byte to string conversion.
+     * @param maxFields The maximum number of fields to be parsed
+     * @param maxLength The maximum total size of the fields
+     * @return A {@link CompletableFuture} that will provide the {@link Fields} or a failure.
+     * @see #from(Content.Source, Attributes, Charset, int, int)
+     */
     public static CompletableFuture<Fields> from(Request request, Charset charset, int maxFields, int maxLength)
     {
         return from(request, request, charset, maxFields, maxLength);
     }
 
+    /**
+     * Find or create a {@link FormFields} from a {@link Content.Source}.
+     * @param source The {@link Content.Source} from which to read the fields.
+     * @param attributes The {@link Attributes} in which to look for an existing {@link FormFields}, else in which to
+     *                   add the fields, using the classname as the attribute name.
+     * @param charset the {@link Charset} to use for byte to string conversion.
+     * @param maxFields The maximum number of fields to be parsed
+     * @param maxLength The maximum total size of the fields
+     * @return A {@link CompletableFuture} that will provide the {@link Fields} or a failure.
+     */
     static CompletableFuture<Fields> from(Content.Source source, Attributes attributes, Charset charset, int maxFields, int maxLength)
     {
         Object attr = attributes.getAttribute(FormFields.class.getName());
@@ -128,7 +187,6 @@ private static int getRequestAttribute(Request request, String attribute)
         }
     }
 
-    private final Content.Source _source;
     private final Fields _fields;
     private final CharsetStringBuilder _builder;
     private final int _maxFields;
@@ -138,10 +196,9 @@ private static int getRequestAttribute(Request request, String attribute)
     private int _percent = 0;
     private byte _percentCode;
 
-    public FormFields(Content.Source source, Charset charset, int maxFields, int maxSize)
+    private FormFields(Content.Source source, Charset charset, int maxFields, int maxSize)
     {
         super(source);
-        _source = source;
         _maxFields = maxFields;
         _maxLength = maxSize;
         _builder = CharsetStringBuilder.forCharset(charset);
@@ -225,7 +282,7 @@ protected Fields parse(Content.Chunk chunk) throws CharacterCodingException
                     Fields.Field field = new Fields.Field(_name, value);
                     _name = null;
                     value = null;
-                    if (_maxFields > 0 && _fields.getSize() >= _maxFields)
+                    if (_maxFields >= 0 && _fields.getSize() >= _maxFields)
                         throw new IllegalStateException("form with too many fields > " + _maxFields);
                     _fields.add(field);
                 }
diff --git a/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/FormFieldsTest.java b/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/FormFieldsTest.java
index 4d00dddb5efc..e6ecab2b15a7 100644
--- a/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/FormFieldsTest.java
+++ b/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/FormFieldsTest.java
@@ -25,6 +25,7 @@
 import org.eclipse.jetty.util.BufferUtil;
 import org.eclipse.jetty.util.Callback;
 import org.eclipse.jetty.util.Fields;
+import org.eclipse.jetty.util.FutureCallback;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.MethodSource;
@@ -61,9 +62,11 @@ public void testFormFields(List<String> chunks, Charset charset, int maxFields,
         assertFalse(futureFields.isDone());
 
         int last = chunks.size() - 1;
+        FutureCallback eof = new FutureCallback();
         for (int i = 0; i <= last; i++)
-            source.write(i == last, BufferUtil.toBuffer(chunks.get(i), charset), Callback.NOOP);
+            source.write(i == last, BufferUtil.toBuffer(chunks.get(i), charset), i == last ? eof : Callback.NOOP);
 
+        assertTrue(eof.isDone());
         assertTrue(futureFields.isDone());
 
         try
diff --git a/jetty-ee10/jetty-ee10-quickstart/src/main/java/org/eclipse/jetty/ee10/quickstart/QuickStartGeneratorConfiguration.java b/jetty-ee10/jetty-ee10-quickstart/src/main/java/org/eclipse/jetty/ee10/quickstart/QuickStartGeneratorConfiguration.java
index 14bd1ce54f6c..f99ebd5ad828 100644
--- a/jetty-ee10/jetty-ee10-quickstart/src/main/java/org/eclipse/jetty/ee10/quickstart/QuickStartGeneratorConfiguration.java
+++ b/jetty-ee10/jetty-ee10-quickstart/src/main/java/org/eclipse/jetty/ee10/quickstart/QuickStartGeneratorConfiguration.java
@@ -764,7 +764,7 @@ private void outholder(XmlAppendable out, MetaData md, ServletHolder holder) thr
         }
 
         //multipart-config
-        MultipartConfigElement multipartConfig = ((ServletHolder.Registration)holder.getRegistration()).getMultipartConfig();
+        MultipartConfigElement multipartConfig = holder.getRegistration().getMultipartConfigElement();
         if (multipartConfig != null)
         {
             out.openTag("multipart-config", origin(md, holder.getName() + ".servlet.multipart-config"));
diff --git a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/Dispatcher.java b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/Dispatcher.java
index d1bc1702c1f0..4cf48e546e76 100644
--- a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/Dispatcher.java
+++ b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/Dispatcher.java
@@ -309,6 +309,15 @@ public Object getAttribute(String name)
                 {
                     return null;
                 }
+                case ServletContextRequest.MULTIPART_CONFIG_ELEMENT ->
+                {
+                    // If we already have future parts, return the configuration of the wrapped request.
+                    if (super.getAttribute(ServletMultiPartFormData.class.getName()) != null)
+                        return super.getAttribute(name);
+                    // otherwise, return the configuration of this mapping
+                    return _mappedServlet.getServletHolder().getMultipartConfigElement();
+                }
+
                 default ->
                 {
                     return super.getAttribute(name);
diff --git a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/PreloadFormHandler.java b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/EagerFormHandler.java
similarity index 84%
rename from jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/PreloadFormHandler.java
rename to jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/EagerFormHandler.java
index bad6553cb664..64940c0cda7c 100644
--- a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/PreloadFormHandler.java
+++ b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/EagerFormHandler.java
@@ -24,20 +24,20 @@
 import org.eclipse.jetty.util.Callback;
 
 /**
- * Handler to asynchronously preload & parse {@link MimeTypes.Type#FORM_ENCODED} and
+ * Handler to eagerly and asynchronously read & parse {@link MimeTypes.Type#FORM_ENCODED} and
  * {@link MimeTypes.Type#MULTIPART_FORM_DATA} content prior to invoking the {@link ServletHandler},
  * which can then consume them with blocking APIs but without blocking.
  * @see FormFields#from(Request)
  * @see ServletMultiPartFormData#from(ServletRequest)
  */
-public class PreloadFormHandler extends Handler.Wrapper
+public class EagerFormHandler extends Handler.Wrapper
 {
-    public PreloadFormHandler()
+    public EagerFormHandler()
     {
         this(null);
     }
 
-    public PreloadFormHandler(Handler handler)
+    public EagerFormHandler(Handler handler)
     {
         super(handler);
     }
@@ -63,15 +63,11 @@ public boolean handle(Request request, org.eclipse.jetty.server.Response respons
         if (future == null)
             return super.handle(request, response, callback);
 
-        if (future.isDone())
-        {
-            if (!super.handle(request, response, callback))
-                callback.failed(new IllegalStateException("Not Handled"));
-            return true;
-        }
-
         future.whenComplete((result, failure) ->
         {
+            // The result and failure are not handled here. Rather we call the next handler
+            // to allow the normal processing to handle the result or failure, which will be
+            // provided via the attribute to ServletApiRequest#getParts()
             try
             {
                 if (!super.handle(request, response, callback))
diff --git a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletContextRequest.java b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletContextRequest.java
index a3d53eee6297..17da4f12ff6e 100644
--- a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletContextRequest.java
+++ b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletContextRequest.java
@@ -240,7 +240,7 @@ public Object getAttribute(String name)
             case "jakarta.servlet.request.key_size" -> super.getAttribute(SecureRequestCustomizer.KEY_SIZE_ATTRIBUTE);
             case "jakarta.servlet.request.ssl_session_id" -> super.getAttribute(SecureRequestCustomizer.SSL_SESSION_ID_ATTRIBUTE);
             case "jakarta.servlet.request.X509Certificate" -> super.getAttribute(SecureRequestCustomizer.PEER_CERTIFICATES_ATTRIBUTE);
-            case ServletContextRequest.MULTIPART_CONFIG_ELEMENT -> _matchedResource.getResource().getServletHolder().getMultipartConfig();
+            case ServletContextRequest.MULTIPART_CONFIG_ELEMENT -> _matchedResource.getResource().getServletHolder().getMultipartConfigElement();
             case FormFields.MAX_FIELDS_ATTRIBUTE -> getServletContext().getServletContextHandler().getMaxFormKeys();
             case FormFields.MAX_LENGTH_ATTRIBUTE -> getServletContext().getServletContextHandler().getMaxFormContentSize();
             default -> super.getAttribute(name);
@@ -259,8 +259,12 @@ public Set<String> getAttributeNameSet()
             names.add("jakarta.servlet.request.ssl_session_id");
         if (names.contains(SecureRequestCustomizer.PEER_CERTIFICATES_ATTRIBUTE))
             names.add("jakarta.servlet.request.X509Certificate");
-        if (_matchedResource.getResource().getServletHolder().getMultipartConfig() != null)
+        if (_matchedResource.getResource().getServletHolder().getMultipartConfigElement() != null)
             names.add(ServletContextRequest.MULTIPART_CONFIG_ELEMENT);
+        if (getServletContext().getServletContextHandler().getMaxFormKeys() >= 0)
+            names.add(FormFields.MAX_FIELDS_ATTRIBUTE);
+        if (getServletContext().getServletContextHandler().getMaxFormContentSize() >= 0L)
+            names.add(FormFields.MAX_FIELDS_ATTRIBUTE);
         return names;
     }
 
diff --git a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletHolder.java b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletHolder.java
index 2404db1c6425..a290c7d8d8b4 100644
--- a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletHolder.java
+++ b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletHolder.java
@@ -155,9 +155,9 @@ public ServletHolder(Class<? extends Servlet> servlet)
         setHeldClass(servlet);
     }
 
-    public Object getMultipartConfig()
+    public MultipartConfigElement getMultipartConfigElement()
     {
-        return _registration == null ? null : _registration.getMultipartConfig();
+        return _registration == null ? null : _registration.getMultipartConfigElement();
     }
 
     /**
@@ -916,7 +916,7 @@ public String getServletName()
 
     public class Registration extends HolderRegistration implements ServletRegistration.Dynamic
     {
-        protected MultipartConfigElement _multipartConfig;
+        protected MultipartConfigElement _multipartConfigElement;
 
         @Override
         public Set<String> addMapping(String... urlPatterns)
@@ -991,12 +991,12 @@ public int getInitOrder()
         @Override
         public void setMultipartConfig(MultipartConfigElement element)
         {
-            _multipartConfig = element;
+            _multipartConfigElement = element;
         }
 
-        public MultipartConfigElement getMultipartConfig()
+        public MultipartConfigElement getMultipartConfigElement()
         {
-            return _multipartConfig;
+            return _multipartConfigElement;
         }
 
         @Override
diff --git a/jetty-ee10/jetty-ee10-servlet/src/test/java/org/eclipse/jetty/ee10/servlet/MultiPartServletTest.java b/jetty-ee10/jetty-ee10-servlet/src/test/java/org/eclipse/jetty/ee10/servlet/MultiPartServletTest.java
index 4edbf4c2b86e..9e46e56f6789 100644
--- a/jetty-ee10/jetty-ee10-servlet/src/test/java/org/eclipse/jetty/ee10/servlet/MultiPartServletTest.java
+++ b/jetty-ee10/jetty-ee10-servlet/src/test/java/org/eclipse/jetty/ee10/servlet/MultiPartServletTest.java
@@ -93,7 +93,7 @@ public void before() throws Exception
         tmpDirString = tmpDir.toAbsolutePath().toString();
     }
 
-    private void start(HttpServlet servlet, MultipartConfigElement config, boolean preload) throws Exception
+    private void start(HttpServlet servlet, MultipartConfigElement config, boolean eager) throws Exception
     {
         config = config == null ? new MultipartConfigElement(tmpDirString, MAX_FILE_SIZE, -1, 0) : config;
         server = new Server(null, null, null);
@@ -110,8 +110,8 @@ private void start(HttpServlet servlet, MultipartConfigElement config, boolean p
         gzipHandler.addIncludedMimeTypes("multipart/form-data");
         gzipHandler.setMinGzipSize(32);
 
-        if (preload)
-            gzipHandler.setHandler(new PreloadFormHandler());
+        if (eager)
+            gzipHandler.setHandler(new EagerFormHandler());
 
         servletContextHandler.insertHandler(gzipHandler);
 
@@ -131,7 +131,7 @@ public void stop() throws Exception
 
     @ParameterizedTest
     @ValueSource(booleans = {true, false})
-    public void testLargePart(boolean preload) throws Exception
+    public void testLargePart(boolean eager) throws Exception
     {
         start(new HttpServlet()
         {
@@ -140,7 +140,7 @@ protected void service(HttpServletRequest req, HttpServletResponse resp)
             {
                 req.getParameterMap();
             }
-        }, new MultipartConfigElement(tmpDirString), preload);
+        }, new MultipartConfigElement(tmpDirString), eager);
 
         OutputStreamRequestContent content = new OutputStreamRequestContent();
         MultiPartRequestContent multiPart = new MultiPartRequestContent();
@@ -173,7 +173,7 @@ protected void service(HttpServletRequest req, HttpServletResponse resp)
 
     @ParameterizedTest
     @ValueSource(booleans = {true, false})
-    public void testManyParts(boolean preload) throws Exception
+    public void testManyParts(boolean eager) throws Exception
     {
         start(new HttpServlet()
         {
@@ -182,7 +182,7 @@ protected void service(HttpServletRequest req, HttpServletResponse resp)
             {
                 req.getParameterMap();
             }
-        }, new MultipartConfigElement(tmpDirString), preload);
+        }, new MultipartConfigElement(tmpDirString), eager);
 
         byte[] byteArray = new byte[1024];
         Arrays.fill(byteArray, (byte)1);
@@ -212,7 +212,7 @@ protected void service(HttpServletRequest req, HttpServletResponse resp)
 
     @ParameterizedTest
     @ValueSource(booleans = {true, false})
-    public void testMaxRequestSize(boolean preload) throws Exception
+    public void testMaxRequestSize(boolean eager) throws Exception
     {
         start(new HttpServlet()
         {
@@ -221,7 +221,7 @@ protected void service(HttpServletRequest req, HttpServletResponse resp) throws
             {
                 req.getParameterMap();
             }
-        }, new MultipartConfigElement(tmpDirString, -1, 1024, 1024 * 1024 * 8), preload);
+        }, new MultipartConfigElement(tmpDirString, -1, 1024, 1024 * 1024 * 8), eager);
 
         OutputStreamRequestContent content = new OutputStreamRequestContent();
         MultiPartRequestContent multiPart = new MultiPartRequestContent();
@@ -282,7 +282,7 @@ private static void assert400orEof(InputStreamResponseListener listener, Consume
 
     @ParameterizedTest
     @ValueSource(booleans = {true, false})
-    public void testSimpleMultiPart(boolean preload) throws Exception
+    public void testSimpleMultiPart(boolean eager) throws Exception
     {
         start(new HttpServlet()
         {
@@ -300,7 +300,7 @@ protected void service(HttpServletRequest request, HttpServletResponse response1
                 String content1 = IO.toString(part.getInputStream(), UTF_8);
                 assertEquals("content1", content1);
             }
-        }, null, preload);
+        }, null, eager);
 
         try (Socket socket = new Socket("localhost", connector.getLocalPort()))
         {
@@ -334,7 +334,7 @@ protected void service(HttpServletRequest request, HttpServletResponse response1
 
     @ParameterizedTest
     @ValueSource(booleans = {true, false})
-    public void testTempFilesDeletedOnError(boolean preload) throws Exception
+    public void testTempFilesDeletedOnError(boolean eager) throws Exception
     {
         byte[] bytes = new byte[2 * MAX_FILE_SIZE];
         Arrays.fill(bytes, (byte)1);
@@ -348,7 +348,7 @@ protected void service(HttpServletRequest request, HttpServletResponse response1
                 // Should throw as the max file size is exceeded.
                 request.getParts();
             }
-        }, null, preload);
+        }, null, eager);
 
         MultiPartRequestContent multiPart = new MultiPartRequestContent();
         multiPart.addPart(new MultiPart.ContentSourcePart("largePart", "largeFile.bin", HttpFields.EMPTY, new BytesRequestContent(bytes)));
@@ -373,7 +373,7 @@ protected void service(HttpServletRequest request, HttpServletResponse response1
 
     @ParameterizedTest
     @ValueSource(booleans = {true, false})
-    public void testMultiPartGzip(boolean preload) throws Exception
+    public void testMultiPartGzip(boolean eager) throws Exception
     {
         start(new HttpServlet()
         {
@@ -397,7 +397,7 @@ protected void service(HttpServletRequest request, HttpServletResponse response1
                 echoParts.close();
                 IO.copy(Content.Source.asInputStream(echoParts), response1.getOutputStream());
             }
-        }, null, preload);
+        }, null, eager);
 
         // Do not automatically handle gzip.
         client.getContentDecoderFactories().clear();
@@ -437,7 +437,7 @@ protected void service(HttpServletRequest request, HttpServletResponse response1
 
     @ParameterizedTest
     @ValueSource(booleans = {true, false})
-    public void testDoubleReadFromPart(boolean preload) throws Exception
+    public void testDoubleReadFromPart(boolean eager) throws Exception
     {
         start(new HttpServlet()
         {
@@ -451,7 +451,7 @@ protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws S
                     resp.getWriter().println("Part: name=" + part.getName() + ", size=" + part.getSize() + ", content=" + IO.toString(part.getInputStream()));
                 }
             }
-        }, null, preload);
+        }, null, eager);
 
         String contentString = "the quick brown fox jumps over the lazy dog, " +
             "the quick brown fox jumps over the lazy dog";
@@ -473,7 +473,7 @@ protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws S
 
     @ParameterizedTest
     @ValueSource(booleans = {true, false})
-    public void testPartAsParameter(boolean preload) throws Exception
+    public void testPartAsParameter(boolean eager) throws Exception
     {
         start(new HttpServlet()
         {
@@ -488,7 +488,7 @@ protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws S
                     resp.getWriter().println("Parameter: " + entry.getKey() + "=" + entry.getValue()[0]);
                 }
             }
-        }, null, preload);
+        }, null, eager);
 
         String contentString = "the quick brown fox jumps over the lazy dog, " +
             "the quick brown fox jumps over the lazy dog";
diff --git a/jetty-ee10/jetty-ee10-webapp/src/main/java/org/eclipse/jetty/ee10/webapp/StandardDescriptorProcessor.java b/jetty-ee10/jetty-ee10-webapp/src/main/java/org/eclipse/jetty/ee10/webapp/StandardDescriptorProcessor.java
index 0e4e9f8d2b03..75a8ec270979 100644
--- a/jetty-ee10/jetty-ee10-webapp/src/main/java/org/eclipse/jetty/ee10/webapp/StandardDescriptorProcessor.java
+++ b/jetty-ee10/jetty-ee10-webapp/src/main/java/org/eclipse/jetty/ee10/webapp/StandardDescriptorProcessor.java
@@ -588,7 +588,7 @@ public void visitServlet(WebAppContext context, Descriptor descriptor, XmlParser
                 case WebFragment:
                 {
                     //another fragment set the value, this fragment's values must match exactly or it is an error
-                    MultipartConfigElement cfg = ((ServletHolder.Registration)holder.getRegistration()).getMultipartConfig();
+                    MultipartConfigElement cfg = holder.getRegistration().getMultipartConfigElement();
 
                     if (cfg.getMaxFileSize() != element.getMaxFileSize())
                         throw new IllegalStateException("Conflicting multipart-config max-file-size for servlet " + name + " in " + descriptor.getURI());

From 1b4703990dd587c19854a8c641052dbd19ab43b0 Mon Sep 17 00:00:00 2001
From: gregw <gregw@webtide.com>
Date: Fri, 30 Jun 2023 11:57:05 +0200
Subject: [PATCH 17/19] Experiment with a fully async
 ContentSourceCompletableFuture

updates from review
---
 .../java/org/eclipse/jetty/ee10/servlet/EagerFormHandler.java   | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/EagerFormHandler.java b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/EagerFormHandler.java
index 64940c0cda7c..015d051edda4 100644
--- a/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/EagerFormHandler.java
+++ b/jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/EagerFormHandler.java
@@ -24,7 +24,7 @@
 import org.eclipse.jetty.util.Callback;
 
 /**
- * Handler to eagerly and asynchronously read & parse {@link MimeTypes.Type#FORM_ENCODED} and
+ * Handler to eagerly and asynchronously read and parse {@link MimeTypes.Type#FORM_ENCODED} and
  * {@link MimeTypes.Type#MULTIPART_FORM_DATA} content prior to invoking the {@link ServletHandler},
  * which can then consume them with blocking APIs but without blocking.
  * @see FormFields#from(Request)

From dff02022e9ddda42776a71d109f7968ed178b685 Mon Sep 17 00:00:00 2001
From: gregw <gregw@webtide.com>
Date: Fri, 30 Jun 2023 12:33:54 +0200
Subject: [PATCH 18/19] Experiment with a fully async
 ContentSourceCompletableFuture

updates from review
---
 .../src/main/java/org/eclipse/jetty/server/FormFields.java | 5 +++--
 .../test/java/org/eclipse/jetty/server/FormFieldsTest.java | 7 +++++--
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/jetty-core/jetty-server/src/main/java/org/eclipse/jetty/server/FormFields.java b/jetty-core/jetty-server/src/main/java/org/eclipse/jetty/server/FormFields.java
index 806b43e688b9..eaf96ccb5b87 100644
--- a/jetty-core/jetty-server/src/main/java/org/eclipse/jetty/server/FormFields.java
+++ b/jetty-core/jetty-server/src/main/java/org/eclipse/jetty/server/FormFields.java
@@ -148,8 +148,9 @@ public static CompletableFuture<Fields> from(Request request, Charset charset, i
     /**
      * Find or create a {@link FormFields} from a {@link Content.Source}.
      * @param source The {@link Content.Source} from which to read the fields.
-     * @param attributes The {@link Attributes} in which to look for an existing {@link FormFields}, else in which to
-     *                   add the fields, using the classname as the attribute name.
+     * @param attributes The {@link Attributes} in which to look for an existing {@link CompletableFuture} of
+     *                   {@link FormFields}, using the classname as the attribute name.  If not found the attribute
+     *                   is set with the created {@link CompletableFuture} of {@link FormFields}.
      * @param charset the {@link Charset} to use for byte to string conversion.
      * @param maxFields The maximum number of fields to be parsed
      * @param maxLength The maximum total size of the fields
diff --git a/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/FormFieldsTest.java b/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/FormFieldsTest.java
index e6ecab2b15a7..cfd0b1ec650c 100644
--- a/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/FormFieldsTest.java
+++ b/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/FormFieldsTest.java
@@ -18,6 +18,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.TimeUnit;
 import java.util.stream.Stream;
 
 import org.eclipse.jetty.io.content.AsyncContent;
@@ -55,6 +56,7 @@ public static Stream<Arguments> tests()
     @ParameterizedTest
     @MethodSource("tests")
     public void testFormFields(List<String> chunks, Charset charset, int maxFields, int maxLength, Map<String, String> expected)
+        throws Exception
     {
         AsyncContent source = new AsyncContent();
         Attributes attributes = new Attributes.Mapped();
@@ -66,11 +68,12 @@ public void testFormFields(List<String> chunks, Charset charset, int maxFields,
         for (int i = 0; i <= last; i++)
             source.write(i == last, BufferUtil.toBuffer(chunks.get(i), charset), i == last ? eof : Callback.NOOP);
 
-        assertTrue(eof.isDone());
-        assertTrue(futureFields.isDone());
 
         try
         {
+            eof.get(10, TimeUnit.SECONDS);
+            assertTrue(futureFields.isDone());
+
             Map<String, String> result = new HashMap<>();
             for (Fields.Field f : futureFields.get())
                 result.put(f.getName(), f.getValue());

From e45daca3022f73927aeb1831a31a16789d3b122f Mon Sep 17 00:00:00 2001
From: Simone Bordet <simone.bordet@gmail.com>
Date: Fri, 30 Jun 2023 16:03:25 +0200
Subject: [PATCH 19/19] Improved javadocs of ContentSourceCompletableFuture.

Signed-off-by: Simone Bordet <simone.bordet@gmail.com>
---
 .../ContentSourceCompletableFuture.java       | 81 +++++++++++--------
 1 file changed, 46 insertions(+), 35 deletions(-)

diff --git a/jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/ContentSourceCompletableFuture.java b/jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/ContentSourceCompletableFuture.java
index ff0ef9dc7e33..f44d92832618 100644
--- a/jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/ContentSourceCompletableFuture.java
+++ b/jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/ContentSourceCompletableFuture.java
@@ -19,31 +19,36 @@
 import org.eclipse.jetty.io.Content;
 
 /**
- * A utility class to convert content from a {@link Content.Source} to an instance
- * available via a {@link CompletableFuture}.
- * <p>
- * An example usage to asynchronously read UTF-8 content is:
- * </p>
+ * <p>A utility class to convert content from a {@link Content.Source} to an instance
+ * available via a {@link CompletableFuture}.</p>
+ * <p>An example usage to asynchronously read UTF-8 content is:</p>
  * <pre>{@code
- *     public static class FutureUtf8String extends ContentSourceCompletableFuture<String>;
+ * public static class CompletableUTF8String extends ContentSourceCompletableFuture<String>;
+ * {
+ *     private final Utf8StringBuilder builder = new Utf8StringBuilder();
+ *
+ *     public CompletableUTF8String(Content.Source content)
+ *     {
+ *         super(content);
+ *     }
+ *
+ *     @Override
+ *     protected String parse(Content.Chunk chunk) throws Throwable
  *     {
- *         Utf8StringBuilder builder = new Utf8StringBuilder();
+ *         // Accumulate the chunk bytes.
+ *         if (chunk.hasRemaining())
+ *             builder.append(chunk.getByteBuffer());
  *
- *         public FutureUtf8String(Content.Source content)
- *         {
- *             super(content);
- *         }
+ *         // Not the last chunk, the result is not ready yet.
+ *         if (!chunk.isLast())
+ *             return null;
  *
- *         @Override
- *         protected String parse(Content.Chunk chunk) throws Throwable
- *         {
- *             if (chunk.hasRemaining())
- *                 builder.append(chunk.getByteBuffer());
- *             return chunk.isLast() ? builder.takeCompleteString(IllegalStateException::new) : null;
- *         }
+ *         // The result is ready.
+ *         return builder.takeCompleteString(IllegalStateException::new);
  *     }
- *     ...
- *     new FutureUtf8String(source).thenAccept(System.err::println);
+ * }
+ * 
+ * new CompletableUTF8String(source).thenAccept(System.err::println);
  * }</pre>
  */
 public abstract class ContentSourceCompletableFuture<X> extends CompletableFuture<X>
@@ -56,12 +61,15 @@ public ContentSourceCompletableFuture(Content.Source content)
     }
 
     /**
-     * Progress the parsing, {@link Content.Source#read() reading} and/or {@link Content.Source#demand(Runnable) demanding}
-     * as necessary.
-     * <p>
-     * This method must be called once to initiate the reading and parsing,
-     * and is then called to progress parsing in response to any {@link Content.Source#demand(Runnable) demand} calls.
-     * </p>
+     * <p>Initiates the parsing of the {@link Content.Source}.</p>
+     * <p>For every valid chunk that is read, {@link #parse(Content.Chunk)}
+     * is called, until a result is produced that is used to
+     * complete this {@link CompletableFuture}.</p>
+     * <p>Internally, this method is called multiple times to progress
+     * the parsing in response to {@link Content.Source#demand(Runnable)}
+     * calls.</p>
+     * <p>Exceptions thrown during parsing result in this
+     * {@link CompletableFuture} to be completed exceptionally.</p>
      */
     public void parse()
     {
@@ -109,21 +117,24 @@ public void parse()
     }
 
     /**
-     * Called to parse a {@link org.eclipse.jetty.io.Content.Chunk}
-     * @param chunk The chunk containing content to parse. The chunk will never be null nor a
+     * <p>Called by {@link #parse()} to parse a {@link org.eclipse.jetty.io.Content.Chunk}.</p>
+     *
+     * @param chunk The chunk containing content to parse. The chunk will never be {@code null} nor a
      *              {@link org.eclipse.jetty.io.Content.Chunk#isFailure(Content.Chunk) failure chunk}.
-     *              If references to the content of the chunk are to be held beyond the scope of this call,
-     *              then implementations must call {@link Content.Chunk#retain()} and {@link Content.Chunk#release()}
-     *              as appropriate.
-     * @return The parsed {@code X} instance or null if parsing is not yet complete
-     * @throws Throwable Thrown if there is an error parsing
+     *              If the chunk is stored away to be used later beyond the scope of this call,
+     *              then implementations must call {@link Content.Chunk#retain()} and
+     *              {@link Content.Chunk#release()} as appropriate.
+     * @return The parsed {@code X} result instance or {@code null} if parsing is not yet complete
+     * @throws Throwable If there is an error parsing
      */
     protected abstract X parse(Content.Chunk chunk) throws Throwable;
 
     /**
-     * @param cause A {@link Content.Chunk#isLast() non-last}
+     * <p>Callback method that informs the parsing about how to handle transient failures.</p>
+     *
+     * @param cause A transient failure obtained by reading a {@link Content.Chunk#isLast() non-last}
      *             {@link org.eclipse.jetty.io.Content.Chunk#isFailure(Content.Chunk) failure chunk}
-     * @return True if the chunk can be ignored.
+     * @return {@code true} if the transient failure can be ignored, {@code false} otherwise
      */
     protected boolean onTransientFailure(Throwable cause)
     {