Merge pull request #5953 from eclipse/jetty-10.0.x-5605-wakeup-blocke…

…d-threads

Jetty 10.0.x Fix #5605 Unblock non container Threads

jetty-server/src/main/java/org/eclipse/jetty/server/AsyncContentProducer.java

@@ -14,20 +14,23 @@
 package org.eclipse.jetty.server;
 
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.locks.Condition;
 
 import org.eclipse.jetty.http.BadMessageException;
 import org.eclipse.jetty.http.HttpStatus;
+import org.eclipse.jetty.util.thread.AutoLock;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 /**
- * Non-blocking {@link ContentProducer} implementation. Calling {@link #nextContent()} will never block
+ * Non-blocking {@link ContentProducer} implementation. Calling {@link ContentProducer#nextContent()} will never block
  * but will return null when there is no available content.
  */
 class AsyncContentProducer implements ContentProducer
 {
     private static final Logger LOG = LoggerFactory.getLogger(AsyncContentProducer.class);
 
+    private final AutoLock _lock = new AutoLock();
     private final HttpChannel _httpChannel;
     private HttpInput.Interceptor _interceptor;
     private HttpInput.Content _rawContent;
@@ -41,9 +44,16 @@ class AsyncContentProducer implements ContentProducer
         _httpChannel = httpChannel;
     }
 
+    @Override
+    public AutoLock lock()
+    {
+        return _lock.lock();
+    }
+
     @Override
     public void recycle()
     {
+        assertLocked();
         if (LOG.isDebugEnabled())
             LOG.debug("recycling {}", this);
         _interceptor = null;
@@ -57,18 +67,21 @@ public void recycle()
     @Override
     public HttpInput.Interceptor getInterceptor()
     {
+        assertLocked();
         return _interceptor;
     }
 
     @Override
     public void setInterceptor(HttpInput.Interceptor interceptor)
     {
+        assertLocked();
         this._interceptor = interceptor;
     }
 
     @Override
     public int available()
     {
+        assertLocked();
         HttpInput.Content content = nextTransformedContent();
         int available = content == null ? 0 : content.remaining();
         if (LOG.isDebugEnabled())
@@ -79,6 +92,7 @@ public int available()
     @Override
     public boolean hasContent()
     {
+        assertLocked();
         boolean hasContent = _rawContent != null;
         if (LOG.isDebugEnabled())
             LOG.debug("hasContent = {} {}", hasContent, this);
@@ -88,6 +102,7 @@ public boolean hasContent()
     @Override
     public boolean isError()
     {
+        assertLocked();
         if (LOG.isDebugEnabled())
             LOG.debug("isError = {} {}", _error, this);
         return _error;
@@ -96,6 +111,7 @@ public boolean isError()
     @Override
     public void checkMinDataRate()
     {
+        assertLocked();
         long minRequestDataRate = _httpChannel.getHttpConfiguration().getMinRequestDataRate();
         if (LOG.isDebugEnabled())
             LOG.debug("checkMinDataRate [m={},t={}] {}", minRequestDataRate, _firstByteTimeStamp, this);
@@ -127,6 +143,7 @@ public void checkMinDataRate()
     @Override
     public long getRawContentArrived()
     {
+        assertLocked();
         if (LOG.isDebugEnabled())
             LOG.debug("getRawContentArrived = {} {}", _rawContentArrived, this);
         return _rawContentArrived;
@@ -135,6 +152,7 @@ public long getRawContentArrived()
     @Override
     public boolean consumeAll(Throwable x)
     {
+        assertLocked();
         if (LOG.isDebugEnabled())
             LOG.debug("consumeAll [e={}] {}", x, this);
         failCurrentContent(x);
@@ -177,11 +195,16 @@ private void failCurrentContent(Throwable x)
             _rawContent.failed(x);
             _rawContent = null;
         }
+
+        HttpInput.ErrorContent errorContent = new HttpInput.ErrorContent(x);
+        _transformedContent = errorContent;
+        _rawContent = errorContent;
     }
 
     @Override
     public boolean onContentProducible()
     {
+        assertLocked();
         if (LOG.isDebugEnabled())
             LOG.debug("onContentProducible {}", this);
         return _httpChannel.getState().onReadReady();
@@ -190,6 +213,7 @@ public boolean onContentProducible()
     @Override
     public HttpInput.Content nextContent()
     {
+        assertLocked();
         HttpInput.Content content = nextTransformedContent();
         if (LOG.isDebugEnabled())
             LOG.debug("nextContent = {} {}", content, this);
@@ -201,6 +225,7 @@ public HttpInput.Content nextContent()
     @Override
     public void reclaim(HttpInput.Content content)
     {
+        assertLocked();
         if (LOG.isDebugEnabled())
             LOG.debug("reclaim {} {}", content, this);
         if (_transformedContent == content)
@@ -215,6 +240,7 @@ public void reclaim(HttpInput.Content content)
     @Override
     public boolean isReady()
     {
+        assertLocked();
         HttpInput.Content content = nextTransformedContent();
         if (content != null)
         {
@@ -274,6 +300,13 @@ private HttpInput.Content nextTransformedContent()
             {
                 // TODO does EOF need to be passed to the interceptors?
 
+                // In case the _rawContent was set by consumeAll(), check the httpChannel
+                // to see if it has a more precise error. Otherwise, the exact same
+                // special content will be returned by the httpChannel.
+                HttpInput.Content refreshedRawContent = produceRawContent();
+                if (refreshedRawContent != null)
+                    _rawContent = refreshedRawContent;
+
                 _error = _rawContent.getError() != null;
                 if (LOG.isDebugEnabled())
                     LOG.debug("raw content is special (with error = {}), returning it {}", _error, this);
@@ -352,6 +385,12 @@ private HttpInput.Content produceRawContent()
         return content;
     }
 
+    private void assertLocked()
+    {
+        if (!_lock.isHeldByCurrentThread())
+            throw new IllegalStateException("ContentProducer must be called within lock scope");
+    }
+
     @Override
     public String toString()
     {
@@ -365,4 +404,53 @@ public String toString()
             _httpChannel
         );
     }
+
+    LockedSemaphore newLockedSemaphore()
+    {
+        return new LockedSemaphore();
+    }
+
+    /**
+     * A semaphore that assumes working under {@link AsyncContentProducer#lock()} scope.
+     */
+    class LockedSemaphore
+    {
+        private final Condition _condition;
+        private int _permits;
+
+        private LockedSemaphore()
+        {
+            this._condition = _lock.newCondition();
+        }
+
+        void assertLocked()
+        {
+            if (!_lock.isHeldByCurrentThread())
+                throw new IllegalStateException("LockedSemaphore must be called within lock scope");
+        }
+
+        void drainPermits()
+        {
+            _permits = 0;
+        }
+
+        void acquire() throws InterruptedException
+        {
+            while (_permits == 0)
+                _condition.await();
+            _permits--;
+        }
+
+        void release()
+        {
+            _permits++;
+            _condition.signal();
+        }
+
+        @Override
+        public String toString()
+        {
+            return getClass().getSimpleName() + " permits=" + _permits;
+        }
+    }
 }

jetty-server/src/main/java/org/eclipse/jetty/server/BlockingContentProducer.java

@@ -13,25 +13,31 @@
 
 package org.eclipse.jetty.server;
 
-import java.util.concurrent.Semaphore;
-
+import org.eclipse.jetty.util.thread.AutoLock;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 /**
- * Blocking implementation of {@link ContentProducer}. Calling {@link #nextContent()} will block when
+ * Blocking implementation of {@link ContentProducer}. Calling {@link ContentProducer#nextContent()} will block when
  * there is no available content but will never return null.
  */
 class BlockingContentProducer implements ContentProducer
 {
     private static final Logger LOG = LoggerFactory.getLogger(BlockingContentProducer.class);
 
-    private final Semaphore _semaphore = new Semaphore(0);
     private final AsyncContentProducer _asyncContentProducer;
+    private final AsyncContentProducer.LockedSemaphore _semaphore;
 
     BlockingContentProducer(AsyncContentProducer delegate)
     {
         _asyncContentProducer = delegate;
+        _semaphore = _asyncContentProducer.newLockedSemaphore();
+    }
+
+    @Override
+    public AutoLock lock()
+    {
+        return _asyncContentProducer.lock();
     }
 
     @Override
@@ -76,7 +82,9 @@ public long getRawContentArrived()
     @Override
     public boolean consumeAll(Throwable x)
     {
-        return _asyncContentProducer.consumeAll(x);
+        boolean eof = _asyncContentProducer.consumeAll(x);
+        _semaphore.release();
+        return eof;
     }
 
     @Override
@@ -142,6 +150,7 @@ public void setInterceptor(HttpInput.Interceptor interceptor)
     @Override
     public boolean onContentProducible()
     {
+        _semaphore.assertLocked();
         // In blocking mode, the dispatched thread normally does not have to be rescheduled as it is normally in state
         // DISPATCHED blocked on the semaphore that just needs to be released for the dispatched thread to resume. This is why
         // this method always returns false.

jetty-server/src/main/java/org/eclipse/jetty/server/ContentProducer.java

@@ -13,6 +13,8 @@
 
 package org.eclipse.jetty.server;
 
+import org.eclipse.jetty.util.thread.AutoLock;
+
 /**
  * ContentProducer is the bridge between {@link HttpInput} and {@link HttpChannel}.
  * It wraps a {@link HttpChannel} and uses the {@link HttpChannel#needContent()},
@@ -24,6 +26,13 @@
  */
 public interface ContentProducer
 {
+    /**
+     * Lock this instance. The lock must be held before any method of this instance's
+     * method be called, and must be manually released afterward.
+     * @return the lock that is guarding this instance.
+     */
+    AutoLock lock();
+
     /**
      * Reset all internal state and clear any held resources.
      */

jetty-server/src/main/java/org/eclipse/jetty/server/HttpChannel.java

@@ -701,9 +701,20 @@ else if (noStack != null)
         }
 
         if (isCommitted())
+        {
             abort(failure);
+        }
         else
-            _state.onError(failure);
+        {
+            try
+            {
+                _state.onError(failure);
+            }
+            catch (IllegalStateException e)
+            {
+                abort(failure);
+            }
+        }
     }
 
     /**

jetty-server/src/main/java/org/eclipse/jetty/server/HttpConnection.java

@@ -309,19 +309,24 @@ else if (filled < 0)
     }
 
     /**
-     * Parse and fill data, looking for content
+     * Parse and fill data, looking for content.
+     * We do parse first, and only fill if we're out of bytes to avoid unnecessary system calls.
      */
     void parseAndFillForContent()
     {
         // When fillRequestBuffer() is called, it must always be followed by a parseRequestBuffer() call otherwise this method
-        // doesn't trigger EOF/earlyEOF which breaks AsyncRequestReadTest.testPartialReadThenShutdown()
-        int filled = Integer.MAX_VALUE;
+        // doesn't trigger EOF/earlyEOF which breaks AsyncRequestReadTest.testPartialReadThenShutdown().
+
+        // This loop was designed by a committee and voted by a majority.
         while (_parser.inContentState())
         {
-            boolean handled = parseRequestBuffer();
-            if (handled || filled <= 0)
+            if (parseRequestBuffer())
+                break;
+            // Re-check the parser state after parsing to avoid filling,
+            // otherwise fillRequestBuffer() would acquire a ByteBuffer
+            // that may be leaked.
+            if (_parser.inContentState() && fillRequestBuffer() <= 0)
                 break;
-            filled = fillRequestBuffer();
         }
     }
 
@@ -412,9 +417,21 @@ private boolean upgrade()
     @Override
     public void onCompleted()
     {
-        // Handle connection upgrades.
-        if (upgrade())
-            return;
+        // If we are fill interested, then a read is pending and we must abort
+        if (isFillInterested())
+        {
+            LOG.warn("Pending read in onCompleted {} {}", this, getEndPoint());
+            abort(new IllegalStateException());
+        }
+        else
+        {
+            // Handle connection upgrades.
+            if (upgrade())
+                return;
+        }
+
+        // Drive to EOF, EarlyEOF or Error
+        boolean complete = _input.consumeAll();
 
         // Finish consuming the request
         // If we are still expecting
@@ -424,7 +441,7 @@ public void onCompleted()
             _parser.close();
         }
         // else abort if we can't consume all
-        else if (_generator.isPersistent() && !_input.consumeAll())
+        else if (_generator.isPersistent() && !complete)
         {
             if (LOG.isDebugEnabled())
                 LOG.debug("unconsumed input {} {}", this, _parser);