Coalesce small buffers in net::BidirectionalStream

components/cronet/android/test/javatests/src/org/chromium/net/TestBidirectionalStreamCallback.java

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.net;
 
 import android.os.ConditionVariable;
 
 import static junit.framework.Assert.assertEquals;
 import static junit.framework.Assert.assertFalse;
 import static junit.framework.Assert.assertNull;
 import static junit.framework.Assert.assertTrue;
 
 import java.nio.ByteBuffer;
 import java.util.ArrayList;
+import java.util.Iterator;
 import java.util.concurrent.Executor;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.ThreadFactory;
 
 /**
  * Callback that tracks information from different callbacks and and has a
  * method to block thread until the stream completes on another thread.
  * Allows to cancel, block stream or throw an exception from an arbitrary step.
  */
 public class TestBidirectionalStreamCallback extends BidirectionalStream.Callback {
     public UrlResponseInfo mResponseInfo;
     public CronetException mError;
 
     public ResponseStep mResponseStep = ResponseStep.NOTHING;
 
     public boolean mOnErrorCalled = false;
     public boolean mOnCanceledCalled = false;
 
     public int mHttpResponseDataLength = 0;
     public String mResponseAsString = "";
 
     public UrlResponseInfo.HeaderBlock mTrailers;
 
     private static final int READ_BUFFER_SIZE = 32 * 1024;
 
+    private boolean mHandleFlush;
     // When false, the consumer is responsible for all calls into the stream
     // that advance it.
     private boolean mAutoAdvance = true;
 
     // Conditionally fail on certain steps.
     private FailureType mFailureType = FailureType.NONE;
     private ResponseStep mFailureStep = ResponseStep.NOTHING;
 
     // Signals when the stream is done either successfully or not.
     private final ConditionVariable mDone = new ConditionVariable();
 
     // Signaled on each step when mAutoAdvance is false.
     private final ConditionVariable mReadStepBlock = new ConditionVariable();
     private final ConditionVariable mWriteStepBlock = new ConditionVariable();
 
     // Executor Service for Cronet callbacks.
     private final ExecutorService mExecutorService =
             Executors.newSingleThreadExecutor(new ExecutorThreadFactory());
     private Thread mExecutorThread;
 
     // position() of ByteBuffer prior to read() call.
     private int mBufferPositionBeforeRead;
 
     // Data to write.
-    private ArrayList<ByteBuffer> mWriteBuffers = new ArrayList<ByteBuffer>();
+    private ArrayList<WriteBuffer> mWriteBuffers = new ArrayList<WriteBuffer>();
+
+    // Buffers that we yet to receive the corresponding onWriteCompleted callback.
+    private ArrayList<WriteBuffer> mWriteBuffersToBeAcked = new ArrayList<WriteBuffer>();
 
     private class ExecutorThreadFactory implements ThreadFactory {
         public Thread newThread(Runnable r) {
             mExecutorThread = new Thread(r);
             return mExecutorThread;
         }
     }
 
+    private static class WriteBuffer {
+        final ByteBuffer mBuffer;
+        final boolean mFlush;
+        public WriteBuffer(ByteBuffer buffer, boolean flush) {
+            mBuffer = buffer;
+            mFlush = flush;
+        }
+    }
+
     public enum ResponseStep {
         NOTHING,
-        ON_REQUEST_HEADERS_SENT,
+        ON_STREAM_READY,
         ON_RESPONSE_STARTED,
         ON_READ_COMPLETED,
         ON_WRITE_COMPLETED,
         ON_TRAILERS,
         ON_CANCELED,
         ON_FAILED,
         ON_SUCCEEDED
     }
 
     public enum FailureType {
         NONE,
         CANCEL_SYNC,
         CANCEL_ASYNC,
         // Same as above, but continues to advance the stream after posting
         // the cancellation task.
         CANCEL_ASYNC_WITHOUT_PAUSE,
         THROW_SYNC
     }
 
+    public void setHandleFlush() {
+        mHandleFlush = true;
+    }
+
     public void setAutoAdvance(boolean autoAdvance) {
         mAutoAdvance = autoAdvance;
     }
 
     public void setFailure(FailureType failureType, ResponseStep failureStep) {
         mFailureStep = failureStep;
         mFailureType = failureType;
     }
 
     public void blockForDone() {
@@ skipping 12 matching lines @@
 
     public Executor getExecutor() {
         return mExecutorService;
     }
 
     public void shutdownExecutor() {
         mExecutorService.shutdown();
     }
 
     public void addWriteData(byte[] data) {
+        addWriteData(data, false);
+    }
+
+    public void addWriteData(byte[] data, boolean flush) {
         ByteBuffer writeBuffer = ByteBuffer.allocateDirect(data.length);
         writeBuffer.put(data);
         writeBuffer.flip();
-        mWriteBuffers.add(writeBuffer);
+        if (flush && !mHandleFlush) {
+            throw new IllegalArgumentException("cannot add flush when auto flush is on");
+        }
+        mWriteBuffers.add(new WriteBuffer(writeBuffer, flush));
+        mWriteBuffersToBeAcked.add(new WriteBuffer(writeBuffer, flush));
     }
 
     @Override
-    public void onRequestHeadersSent(BidirectionalStream stream) {
+    public void onStreamReady(BidirectionalStream stream) {
         assertEquals(mExecutorThread, Thread.currentThread());
         assertFalse(stream.isDone());
         assertEquals(ResponseStep.NOTHING, mResponseStep);
         assertNull(mError);
 
-        mResponseStep = ResponseStep.ON_REQUEST_HEADERS_SENT;
+        mResponseStep = ResponseStep.ON_STREAM_READY;
         if (maybeThrowCancelOrPause(stream, mWriteStepBlock)) {
             return;
         }
         startNextWrite(stream);
     }
 
     @Override
     public void onResponseHeadersReceived(BidirectionalStream stream, UrlResponseInfo info) {
         assertEquals(mExecutorThread, Thread.currentThread());
         assertFalse(stream.isDone());
         assertTrue(mResponseStep == ResponseStep.NOTHING
-                || mResponseStep == ResponseStep.ON_REQUEST_HEADERS_SENT
+                || mResponseStep == ResponseStep.ON_STREAM_READY
                 || mResponseStep == ResponseStep.ON_WRITE_COMPLETED);
         assertNull(mError);
 
         mResponseStep = ResponseStep.ON_RESPONSE_STARTED;
         mResponseInfo = info;
         if (maybeThrowCancelOrPause(stream, mReadStepBlock)) {
             return;
         }
         startNextRead(stream);
     }
@@ skipping 28 matching lines @@
         startNextRead(stream);
     }
 
     @Override
     public void onWriteCompleted(
             BidirectionalStream stream, UrlResponseInfo info, ByteBuffer buffer) {
         assertEquals(mExecutorThread, Thread.currentThread());
         assertFalse(stream.isDone());
         assertNull(mError);
         mResponseStep = ResponseStep.ON_WRITE_COMPLETED;
-        if (!mWriteBuffers.isEmpty()) {
-            assertEquals(buffer, mWriteBuffers.get(0));
-            mWriteBuffers.remove(0);
+        if (!mWriteBuffersToBeAcked.isEmpty()) {
+            assertEquals(buffer, mWriteBuffersToBeAcked.get(0).mBuffer);
+            mWriteBuffersToBeAcked.remove(0);
         }
         if (maybeThrowCancelOrPause(stream, mWriteStepBlock)) {
             return;
         }
         startNextWrite(stream);
     }
 
     @Override
     public void onResponseTrailersReceived(BidirectionalStream stream, UrlResponseInfo info,
             UrlResponseInfo.HeaderBlock trailers) {
@@ skipping 11 matching lines @@
     public void onSucceeded(BidirectionalStream stream, UrlResponseInfo info) {
         assertEquals(mExecutorThread, Thread.currentThread());
         assertTrue(stream.isDone());
         assertTrue(mResponseStep == ResponseStep.ON_RESPONSE_STARTED
                 || mResponseStep == ResponseStep.ON_READ_COMPLETED
                 || mResponseStep == ResponseStep.ON_WRITE_COMPLETED
                 || mResponseStep == ResponseStep.ON_TRAILERS);
         assertFalse(mOnErrorCalled);
         assertFalse(mOnCanceledCalled);
         assertNull(mError);
+        assertEquals(0, mWriteBuffers.size());
+        assertEquals(0, mWriteBuffersToBeAcked.size());
 
         mResponseStep = ResponseStep.ON_SUCCEEDED;
         mResponseInfo = info;
         openDone();
         maybeThrowCancelOrPause(stream, mReadStepBlock);
     }
 
     @Override
     public void onFailed(BidirectionalStream stream, UrlResponseInfo info, CronetException error) {
         assertEquals(mExecutorThread, Thread.currentThread());
@@ skipping 31 matching lines @@
         startNextRead(stream, ByteBuffer.allocateDirect(READ_BUFFER_SIZE));
     }
 
     public void startNextRead(BidirectionalStream stream, ByteBuffer buffer) {
         mBufferPositionBeforeRead = buffer.position();
         stream.read(buffer);
     }
 
     public void startNextWrite(BidirectionalStream stream) {
         if (!mWriteBuffers.isEmpty()) {
-            boolean isLastBuffer = mWriteBuffers.size() == 1;
-            stream.write(mWriteBuffers.get(0), isLastBuffer);
+            if (mHandleFlush) {
+                Iterator<WriteBuffer> iterator = mWriteBuffers.iterator();
+                while (iterator.hasNext()) {
+                    WriteBuffer b = iterator.next();
+                    stream.write(b.mBuffer, !iterator.hasNext());
+                    iterator.remove();
+                    if (b.mFlush) {
+                        stream.flush();
+                        break;
+                    }
+                }
+            } else {
+                boolean isLastBuffer = (mWriteBuffers.size() == 1);
+                stream.write(mWriteBuffers.get(0).mBuffer, isLastBuffer);
+                mWriteBuffers.remove(0);
+            }
         }
     }
 
     public boolean isDone() {
         // It's not mentioned by the Android docs, but block(0) seems to block
         // indefinitely, so have to block for one millisecond to get state
         // without blocking.
         return mDone.block(1);
     }
 
@@ skipping 25 matching lines @@
         };
         if (mFailureType == FailureType.CANCEL_ASYNC
                 || mFailureType == FailureType.CANCEL_ASYNC_WITHOUT_PAUSE) {
             getExecutor().execute(task);
         } else {
             task.run();
         }
         return mFailureType != FailureType.CANCEL_ASYNC_WITHOUT_PAUSE;
     }
 }