Initial implementation of CronetBidirectionalStream.

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.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;
+
+    // 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 class ExecutorThreadFactory implements ThreadFactory {
+        public Thread newThread(Runnable r) {
+            mExecutorThread = new Thread(r);
+            return mExecutorThread;
+        }
+    }
+
+    public enum ResponseStep {
+        NOTHING,
+        ON_REQUEST_HEADERS_SENT,
+        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 setAutoAdvance(boolean autoAdvance) {
+        mAutoAdvance = autoAdvance;
+    }
+
+    public void setFailure(FailureType failureType, ResponseStep failureStep) {
+        mFailureStep = failureStep;
+        mFailureType = failureType;
+    }
+
+    public void blockForDone() {
+        mDone.block();
+    }
+
+    public void waitForNextReadStep() {
+        mReadStepBlock.block();
+        mReadStepBlock.close();
+    }
+
+    public void waitForNextWriteStep() {
+        mWriteStepBlock.block();
+        mWriteStepBlock.close();
+    }
+
+    public Executor getExecutor() {
+        return mExecutorService;
+    }
+
+    public void shutdownExecutor() {
+        mExecutorService.shutdown();
+    }
+
+    public void addWriteData(byte[] data) {
+        ByteBuffer writeBuffer = ByteBuffer.allocateDirect(data.length);
+        writeBuffer.put(data);
+        writeBuffer.flip();
+        mWriteBuffers.add(writeBuffer);
+    }
+
+    @Override
+    public void onRequestHeadersSent(BidirectionalStream stream) {
+        assertEquals(mExecutorThread, Thread.currentThread());
+        assertFalse(stream.isDone());
+        assertEquals(ResponseStep.NOTHING, mResponseStep);
+        assertNull(mError);
+
+        mResponseStep = ResponseStep.ON_REQUEST_HEADERS_SENT;
+        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_WRITE_COMPLETED);
+        assertNull(mError);
+
+        mResponseStep = ResponseStep.ON_RESPONSE_STARTED;
+        mResponseInfo = info;
+        if (maybeThrowCancelOrPause(stream, mReadStepBlock)) {
+            return;
+        }
+        startNextRead(stream);
+    }
+
+    @Override
+    public void onReadCompleted(

[kapishnikov, 2016/01/29 20:08:58]

Do we have any test that does partial read and reuses the existing buffer? E.g.,
the read buffer contains 10 bytes. onReadCompleted() reads 5 bytes and calls
stream.read() with the original buffer.

[mef, 2016/01/29 20:42:19]

testSimpleGetBufferUpdates()

+            BidirectionalStream stream, UrlResponseInfo info, ByteBuffer byteBuffer) {
+        assertEquals(mExecutorThread, Thread.currentThread());
+        assertFalse(stream.isDone());
+        assertTrue(mResponseStep == ResponseStep.ON_RESPONSE_STARTED
+                || mResponseStep == ResponseStep.ON_READ_COMPLETED
+                || mResponseStep == ResponseStep.ON_WRITE_COMPLETED
+                || mResponseStep == ResponseStep.ON_TRAILERS);
+        assertNull(mError);
+
+        mResponseStep = ResponseStep.ON_READ_COMPLETED;
+
+        final byte[] lastDataReceivedAsBytes;
+        final int bytesRead = byteBuffer.position() - mBufferPositionBeforeRead;
+        mHttpResponseDataLength += bytesRead;
+        lastDataReceivedAsBytes = new byte[bytesRead];

[kapishnikov, 2016/01/29 20:08:58]

Since |lastDataReceivedAsBytes| is final it is better to keep the declaration
and the value assignment together, i.e. replace it with
final byte[] lastDataReceivedAsBytes = new byte[bytesRead];

[mef, 2016/01/29 20:42:19]

Done.

+        // Rewind byteBuffer.position() to pre-read() position.
+        byteBuffer.position(mBufferPositionBeforeRead);
+        // This restores byteBuffer.position() to its value on entrance to
+        // this function.
+        byteBuffer.get(lastDataReceivedAsBytes);
+
+        mResponseAsString += new String(lastDataReceivedAsBytes);
+
+        if (maybeThrowCancelOrPause(stream, mReadStepBlock)) {
+            return;
+        }
+        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 (maybeThrowCancelOrPause(stream, mWriteStepBlock)) {
+            return;
+        }
+        startNextWrite(stream);
+    }
+
+    @Override
+    public void onResponseTrailersReceived(BidirectionalStream stream, UrlResponseInfo info,
+            UrlResponseInfo.HeaderBlock trailers) {
+        assertEquals(mExecutorThread, Thread.currentThread());
+        assertFalse(stream.isDone());
+        assertNull(mError);
+        mResponseStep = ResponseStep.ON_TRAILERS;
+        mTrailers = trailers;
+        if (maybeThrowCancelOrPause(stream, mReadStepBlock)) {
+            return;
+        }
+    }
+
+    @Override
+    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);
+
+        mResponseStep = ResponseStep.ON_SUCCEEDED;
+        mResponseInfo = info;
+        openDone();
+        maybeThrowCancelOrPause(stream, mReadStepBlock);
+    }
+
+    @Override
+    public void onFailed(BidirectionalStream stream, UrlResponseInfo info, CronetException error) {

[kapishnikov, 2016/01/29 20:08:58]

Can we add a test that checks that the callback is called with an error that
contains the correct error code? I suspect that its value is always 0.

[mef, 2016/01/29 20:42:19]

Good point, done, see testFailPlainHttp().

+        assertEquals(mExecutorThread, Thread.currentThread());
+        assertTrue(stream.isDone());
+        // Shouldn't happen after success.
+        assertTrue(mResponseStep != ResponseStep.ON_SUCCEEDED);
+        // Should happen at most once for a single stream.
+        assertFalse(mOnErrorCalled);
+        assertFalse(mOnCanceledCalled);
+        assertNull(mError);
+        mResponseStep = ResponseStep.ON_FAILED;
+
+        mOnErrorCalled = true;
+        mError = error;
+        openDone();
+        maybeThrowCancelOrPause(stream, mReadStepBlock);
+    }
+
+    @Override
+    public void onCanceled(BidirectionalStream stream, UrlResponseInfo info) {

[kapishnikov, 2016/01/29 20:08:58]

Do we have any test that checks that onCanceled() is ever called?

[mef, 2016/01/29 20:42:19]

testFailures() -> 
throwOrCancel(FailureType.CANCEL_SYNC, ResponseStep.ON_REQUEST_HEADERS_SENT,
false, false); ->
        assertEquals(failureType == FailureType.CANCEL_SYNC
                        || failureType == FailureType.CANCEL_ASYNC
                        || failureType ==
FailureType.CANCEL_ASYNC_WITHOUT_PAUSE,
                callback.mOnCanceledCalled); 

+        assertEquals(mExecutorThread, Thread.currentThread());
+        assertTrue(stream.isDone());
+        // Should happen at most once for a single stream.
+        assertFalse(mOnCanceledCalled);
+        assertFalse(mOnErrorCalled);
+        assertNull(mError);
+        mResponseStep = ResponseStep.ON_CANCELED;
+
+        mOnCanceledCalled = true;
+        openDone();
+        maybeThrowCancelOrPause(stream, mReadStepBlock);
+    }
+
+    public void startNextRead(BidirectionalStream stream) {
+        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);
+        }
+    }
+
+    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);
+    }
+
+    protected void openDone() {
+        mDone.open();
+    }
+
+    /**
+     * Returns {@code false} if the callback should continue to advance the
+     * stream.
+     */
+    private boolean maybeThrowCancelOrPause(
+            final BidirectionalStream stream, ConditionVariable stepBlock) {
+        if (mResponseStep != mFailureStep || mFailureType == FailureType.NONE) {
+            if (!mAutoAdvance) {
+                stepBlock.open();
+                return true;
+            }
+            return false;
+        }
+
+        if (mFailureType == FailureType.THROW_SYNC) {
+            throw new IllegalStateException("Callback Exception.");
+        }
+        Runnable task = new Runnable() {
+            public void run() {
+                stream.cancel();
+            }
+        };
+        if (mFailureType == FailureType.CANCEL_ASYNC
+                || mFailureType == FailureType.CANCEL_ASYNC_WITHOUT_PAUSE) {
+            getExecutor().execute(task);
+        } else {
+            task.run();
+        }
+        return mFailureType != FailureType.CANCEL_ASYNC_WITHOUT_PAUSE;
+    }
+}