From 93cbeb98fba6ec35570193443e42328a49336629 Mon Sep 17 00:00:00 2001
From: Rahul Behera <rbehera@gmail.com>
Date: Tue, 6 Feb 2024 00:02:52 -0800
Subject: [PATCH] fragmented read buffer fixes & native buffer fix (#54)

* fragmented read buffer fixes

* add 10s timeout to browser

* add more information for failed tests

* fix native write(buffer) issue
---
 build.gradle.kts                              |  9 ++++-
 karma.config.d/karma.conf.js                  |  5 +++
 .../ditchoom/buffer/FragmentedReadBuffer.kt   | 40 ++++++++++++-------
 .../buffer/FragmentedReadBufferTests.kt       | 26 ++++++++++++
 .../com/ditchoom/buffer/NativeBuffer.kt       |  2 +-
 5 files changed, 65 insertions(+), 17 deletions(-)
 create mode 100644 karma.config.d/karma.conf.js

diff --git a/build.gradle.kts b/build.gradle.kts
index 87eab0b..d49386e 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -52,7 +52,14 @@ kotlin {
         js(IR) {
             moduleName = "buffer-kt"
             browser { binaries.library() }
-            nodejs { binaries.library() }
+            nodejs {
+                binaries.library()
+                testTask {
+                    useMocha {
+                        timeout = "10s"
+                    }
+                }
+            }
         }
     }
 
diff --git a/karma.config.d/karma.conf.js b/karma.config.d/karma.conf.js
new file mode 100644
index 0000000..e651f5c
--- /dev/null
+++ b/karma.config.d/karma.conf.js
@@ -0,0 +1,5 @@
+config.client = config.client || {}
+config.client.mocha = config.client.mocha || {}
+config.client.mocha.timeout = 10000
+config.browserNoActivityTimeout = 10000
+config.browserDisconnectTimeout = 10000
diff --git a/src/commonMain/kotlin/com/ditchoom/buffer/FragmentedReadBuffer.kt b/src/commonMain/kotlin/com/ditchoom/buffer/FragmentedReadBuffer.kt
index e05fc0e..3162d7b 100644
--- a/src/commonMain/kotlin/com/ditchoom/buffer/FragmentedReadBuffer.kt
+++ b/src/commonMain/kotlin/com/ditchoom/buffer/FragmentedReadBuffer.kt
@@ -9,9 +9,7 @@ class FragmentedReadBuffer(
     private val first: ReadBuffer,
     private val second: ReadBuffer
 ) : ReadBuffer {
-    private val firstInitialPosition = first.position()
     private val firstInitialLimit = first.limit()
-    private val secondInitialPosition = second.position()
     private val secondInitialLimit = second.limit()
     private var currentPosition = 0
     private var currentLimit = firstInitialLimit + secondInitialLimit
@@ -37,8 +35,8 @@ class FragmentedReadBuffer(
 
     override fun resetForRead() {
         currentPosition = 0
-        first.position(firstInitialPosition)
-        second.position(secondInitialPosition)
+        first.resetForRead()
+        second.resetForRead()
     }
 
     override fun readByte(): Byte {
@@ -143,19 +141,31 @@ class FragmentedReadBuffer(
             out += second
         }
     }
+    fun toSingleBuffer(zone: AllocationZone = AllocationZone.Heap): PlatformBuffer {
+        val firstLimit = firstInitialLimit
+        val secondLimit = secondInitialLimit
+        val initialPosition = position()
+        val buffer = PlatformBuffer.allocate(firstLimit + secondLimit - initialPosition, zone)
+        buffer.write(first)
+        buffer.write(second)
+        buffer.position(initialPosition)
+        return buffer
+    }
 }
 
 fun List<ReadBuffer>.toComposableBuffer(): ReadBuffer {
-    return when (size) {
-        1 -> {
-            first()
-        }
-
-        else -> {
-            FragmentedReadBuffer(
-                first(),
-                subList(1, size).toComposableBuffer()
-            )
-        }
+    if (isEmpty()) {
+        return ReadBuffer.EMPTY_BUFFER
+    }
+    if (size == 1) {
+        return first()
+    }
+    if (size == 2) {
+        return FragmentedReadBuffer(first(), get(1))
     }
+    val half = size / 2
+    return FragmentedReadBuffer(
+        subList(0, half).toComposableBuffer(),
+        subList(half, size).toComposableBuffer()
+    )
 }
diff --git a/src/commonTest/kotlin/com/ditchoom/buffer/FragmentedReadBufferTests.kt b/src/commonTest/kotlin/com/ditchoom/buffer/FragmentedReadBufferTests.kt
index 02eb085..131eadf 100644
--- a/src/commonTest/kotlin/com/ditchoom/buffer/FragmentedReadBufferTests.kt
+++ b/src/commonTest/kotlin/com/ditchoom/buffer/FragmentedReadBufferTests.kt
@@ -413,4 +413,30 @@ class FragmentedReadBufferTests {
         assertEquals("", composableBuffer.readUtf8Line().toString())
         assertTrue { composableBuffer.remaining() == 0 }
     }
+
+    @Test
+    fun largeFragmentedBuffer() {
+        val buffers = mutableListOf<ReadBuffer>()
+        var indexCount = 0
+        do { // 64 byte chunks
+            val buffer = PlatformBuffer.allocate(64)
+            repeat(64 / 4) {
+                buffer.writeInt(indexCount++)
+            }
+            buffers += buffer
+        } while (indexCount < 1024 * 1024)
+        val fragmentedBuffer = buffers.toComposableBuffer() as FragmentedReadBuffer
+        fragmentedBuffer.resetForRead()
+        repeat(indexCount) {
+            assertEquals(it, fragmentedBuffer.readInt(), "failed to read byte on fragmented at $indexCount")
+        }
+        assertEquals(0, fragmentedBuffer.remaining(), "fragmented should have 0 remaining")
+        fragmentedBuffer.resetForRead()
+        val combined = fragmentedBuffer.toSingleBuffer()
+        assertEquals(indexCount * 4, combined.remaining(), "failed to validate remaining")
+        repeat(indexCount) {
+            assertEquals(it, combined.readInt(), "failed to read byte on combined at $indexCount")
+        }
+        assertEquals(0, combined.remaining(), "combined should have 0 remaining")
+    }
 }
diff --git a/src/nativeMain/kotlin/com/ditchoom/buffer/NativeBuffer.kt b/src/nativeMain/kotlin/com/ditchoom/buffer/NativeBuffer.kt
index bf2021a..55d3a01 100644
--- a/src/nativeMain/kotlin/com/ditchoom/buffer/NativeBuffer.kt
+++ b/src/nativeMain/kotlin/com/ditchoom/buffer/NativeBuffer.kt
@@ -74,7 +74,7 @@ data class NativeBuffer(
             writeBytes(buffer.data)
             buffer.data.size
         } else {
-            val numBytes = remaining()
+            val numBytes = buffer.remaining()
             writeBytes(buffer.readByteArray(numBytes))
             numBytes
         }