[Cronet] Implement getOutputStream in CronetHttpURLConnection

components/cronet/android/java/src/org/chromium/net/urlconnection/CronetOutputStream.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.urlconnection;
+
+import org.chromium.net.UploadDataProvider;
+import org.chromium.net.UploadDataSink;
+
+import java.io.IOException;
+import java.io.OutputStream;
+import java.nio.ByteBuffer;
+
+/**
+ * An implementation of {@link java.io.OutputStream} to send data to a server,
+ * when {@link CronetHttpURLConnection#setFixedLengthStreamingMode} is used.
+ * This implementation does not buffer entire request body in memory.

[pauljensen, 2015/03/10 17:31:06]

What threads do we expect this to be called from?  I see problems if read() and
write() are called simultaneously.

[xunjieli, 2015/03/12 21:55:10]

I guess I was assuming that writes happen on the thread that the request is
created on. So read() and write() won't be called at the same time. This is not
clear, so I have edited the docs too.

+ */
+final class CronetOutputStream extends OutputStream implements UploadDataProvider {
+    // CronetOutputStream buffers up to this value and wait for UploadDataStream
+    // to consume the data.
+    // FIXME: confirm this number is what we want to buffer internally.

[pauljensen, 2015/03/10 17:31:06]

can we either resolve this FIXME now or change it to a TODO if it can wait?

[xunjieli, 2015/03/12 21:55:10]

Done.

+    private static int sDefaultBufferLength = 2048;
+    private final CronetHttpURLConnection mConnection;
+    private final long mContentLength;
+    private final ByteBuffer mBuffer;
+    private long mBytesReceived;
+
+    /**
+     * Packaged protected constructor.
+     * @param connection The CronetHttpURLConnection object.
+     * @param contentLength The content length of the request body. Non-zero for
+     *            non-chunked upload.
+     */
+    CronetOutputStream(CronetHttpURLConnection connection, long contentLength) {
+        if (connection == null) {
+            throw new NullPointerException();
+        }
+        if (contentLength < 0) {
+            throw new IllegalArgumentException(
+                    "Content length must be larger than 0 for non-chunked upload.");
+        }
+        mContentLength = contentLength;
+        int bufferSize = (int) Math.min(mContentLength, sDefaultBufferLength);
+        mBuffer = ByteBuffer.allocate(bufferSize);
+        mConnection = connection;
+        mBytesReceived = 0;
+    }
+
+    @Override
+    public long getLength() {
+        return mContentLength;
+    }
+
+    @Override
+    public void read(UploadDataSink uploadDataSink, ByteBuffer byteBuffer) {
+        mBuffer.flip();
+        byteBuffer.put(mBuffer);

[pauljensen, 2015/03/10 17:31:06]

how do we know this won't overflow?  can we add a comment to the fact

[xunjieli, 2015/03/12 21:55:10]

Sorry, I think there's a risk of overflowing. 
Done. I have added a test too.

+        // Reuse this buffer.
+        mBuffer.clear();
+        uploadDataSink.onReadSucceeded(false);
+        // Wait for more data if not enough data is received.
+        if (mBytesReceived < mContentLength) {
+            mConnection.waitForPostData();
+        }
+    }
+
+    @Override
+    public void rewind(UploadDataSink uploadDataSink) {
+        uploadDataSink.onRewindError(null);
+    }
+
+    @Override
+    public void write(int oneByte) throws IOException {
+        if (mBuffer.position() == mBuffer.limit()) {
+            // Wait until buffer is consumed.
+            mConnection.waitForPostDataConsumed();
+        }
+        mBuffer.put((byte) oneByte);
+        mBytesReceived++;
+        if (mBytesReceived == mContentLength) {
+            // Entire post data has been received. Now wait for network stack to
+            // consume it.
+            mConnection.waitForPostDataConsumed();
+        }
+    }
+
+    @Override
+    public void write(byte[] buffer, int offset, int count) throws IOException {
+        if (buffer.length - offset < count || offset < 0 || count < 0) {
+            throw new IndexOutOfBoundsException();
+        }
+        if (count == 0) {
+            return;
+        }
+        int toSent = count;

[pauljensen, 2015/03/10 17:31:06]

how about renaming toSent to toSend

[xunjieli, 2015/03/12 21:55:10]

Done.

+        while (toSent > 0) {
+            if (mBuffer.position() == mBuffer.limit()) {
+                // Wait until buffer is consumed.
+                mConnection.waitForPostDataConsumed();
+            }
+            int sent = Math.min(toSent, mBuffer.limit() - mBuffer.position());
+            mBuffer.put(buffer, offset + count - toSent, sent);
+            toSent -= sent;
+        }
+        mBytesReceived += count;
+        if (mBytesReceived == mContentLength) {
+            // Entire post data has been received. Now wait for network stack to
+            // consume it.
+            mConnection.waitForPostDataConsumed();
+        }
+    }
+}