Fix issue jetty#5499

this PR let the ByteAccumulator recyclable. after invoke ByteAccumulator.transferTo method
we can invoke ByteAccumulator.recycle method to reuse byte[] via ByteAccumulator.newByteArray method

Signed-off-by: Baoyi Chen <chen.bao.yi@qq.com>

jetty-websocket/websocket-common/src/main/java/org/eclipse/jetty/websocket/common/extensions/compress/ByteAccumulator.java

@@ -46,23 +46,23 @@ public ByteAccumulator(int maxOverallBufferSize, ByteBufferPool bufferPool)
 
     public void copyChunk(ByteBuffer buffer)
     {
-        int length = buffer.position();
+        int length = buffer.remaining();
         if (this.length + length > maxSize)
         {
             String err = String.format("Resulting message size [%,d] is too large for configured max of [%,d]", this.length + length, maxSize);
             throw new MessageTooLargeException(err);
         }
 
-        if (length > 0)
+        if (buffer.hasRemaining())
         {
-            chunks.add((ByteBuffer)buffer.flip());
+            chunks.add(buffer);
             this.length += length;
         }
         else
         {
             // release 0 length buffer directly
             if (bufferPool != null)
-                bufferPool.release(buffer);
+                bufferPool.release((ByteBuffer)buffer.clear());
         }
     }
 
@@ -122,7 +122,7 @@ void recycle()
         }
         for (ByteBuffer chunk : chunks)
         {
-            bufferPool.release(chunk);
+            bufferPool.release((ByteBuffer)chunk.clear());
         }
 
         chunks.clear();

jetty-websocket/websocket-common/src/main/java/org/eclipse/jetty/websocket/common/extensions/compress/CompressExtension.java

@@ -193,12 +193,12 @@ int copyChunk(Inflater inflater, ByteAccumulator accumulator, ByteBuffer buf) th
             int read = inflater.inflate(buf.array(), position, capacity - position);
             if (read <= 0)
             {
-                accumulator.copyChunk((ByteBuffer)buf.position(position));
+                accumulator.copyChunk((ByteBuffer)buf.position(position).flip());
                 return read;
             }
             position += read;
         }
-        accumulator.copyChunk((ByteBuffer)buf.position(position));
+        accumulator.copyChunk((ByteBuffer)buf.position(position).flip());
         return position;
     }
 

jetty-websocket/websocket-common/src/test/java/org/eclipse/jetty/websocket/common/extensions/compress/ByteAccumulatorTest.java

@@ -103,19 +103,19 @@ public void testRecycle()
             // 1
             ByteBuffer buf = accumulator.newByteBuffer(10);
             byte[] hello = "Hello".getBytes(UTF_8);
-            buf.put(hello);
+            buf.put(hello).flip();
             accumulator.copyChunk(buf);
 
             // 2
             buf = accumulator.newByteBuffer(10);
             byte[] space = " ".getBytes(UTF_8);
-            buf.put(space);
+            buf.put(space).flip();
             accumulator.copyChunk(buf);
 
             // 3
             buf = accumulator.newByteBuffer(10);
             byte[] world = "World".getBytes(UTF_8);
-            buf.put(world);
+            buf.put(world).flip();
             accumulator.copyChunk(buf);
 
             assertThat("Length", accumulator.getLength(), is(hello.length + space.length + world.length));
@@ -130,25 +130,25 @@ public void testRecycle()
             // 1
             ByteBuffer buf = accumulator.newByteBuffer(10);
             byte[] olleh = "olleH".getBytes(UTF_8);
-            buf.put(olleh);
+            buf.put(olleh).flip();
             accumulator.copyChunk(buf);
 
             // 2
             buf = accumulator.newByteBuffer(10);
             byte[] space = " ".getBytes(UTF_8);
-            buf.put(space);
+            buf.put(space).flip();
             accumulator.copyChunk(buf);
 
             // 3
             buf = accumulator.newByteBuffer(10);
             byte[] dlrow = "dlroW".getBytes(UTF_8);
-            buf.put(dlrow);
+            buf.put(dlrow).flip();
             accumulator.copyChunk(buf);
 
             // 4
             buf = accumulator.newByteBuffer(10);
             byte[] done = " enoD".getBytes(UTF_8);
-            buf.put(done);
+            buf.put(done).flip();
             accumulator.copyChunk(buf);
 
             assertThat("Length", accumulator.getLength(), is(olleh.length + space.length + dlrow.length + done.length));