[Cronet] Implement getOutputStream in CronetHttpURLConnection

components/cronet/android/java/src/org/chromium/net/urlconnection/CronetBufferedOutputStream.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.net.ProtocolException;
+import java.nio.ByteBuffer;
+
+/**
+ * An implementation of {@link java.io.OutputStream} that buffers entire request
+ * body in memory. This is used when neither
+ * {@link CronetHttpURLConnection#setFixedLengthStreamingMode}
+ * nor {@link CronetHttpURLConnection#setChunkedStreamingMode} is set.
+ */
+final class CronetBufferedOutputStream extends OutputStream
+        implements UploadDataProvider {
+    // If content length is not passed in the constructor, this is -1.
+    private final int mInitialContentLength;
+    private final CronetHttpURLConnection mConnection;
+    // Internal buffer that is used to buffer the request body.
+    private ByteBuffer mBuffer;
+    private boolean mConnected = false;
+    private boolean mFirstReadInitiated = false;
+
+    /**
+     * Package protected constructor.
+     * @param connection The CronetHttpURLConnection object.
+     * @param contentLength The content length of the request body. It must not
+     *            be smaller than 0 or bigger than {@link Integer.MAX_VALUE}.
+     */
+    CronetBufferedOutputStream(final CronetHttpURLConnection connection,
+            final long contentLength) {
+        if (connection == null) {
+            throw new NullPointerException();
+        }
+
+        if (contentLength > Integer.MAX_VALUE) {
+            throw new IllegalStateException("Use setFixedLengthStreamingMode()"
+                + " or setChunkedStreamingMode() for requests larger than 2GB.");
+        }
+        if (contentLength < 0) {
+            throw new IllegalArgumentException("Content length < 0.");
+        }
+        mConnection = connection;
+        mInitialContentLength = (int) contentLength;
+        mBuffer = ByteBuffer.allocate(mInitialContentLength);
+    }
+
+    /**
+     * Package protected constructor used when content length is not known.
+     * @param connection The CronetHttpURLConnection object.
+     */
+    CronetBufferedOutputStream(final CronetHttpURLConnection connection) {
+        if (connection == null) {
+            throw new NullPointerException();
+        }
+
+        mConnection = connection;
+        mInitialContentLength = -1;
+        // Buffering without knowing content-length.
+        mBuffer = ByteBuffer.allocate(2048);
+    }
+
+    @Override
+    public void write(int oneByte) throws IOException {
+        ensureCanWrite(1);
+        mBuffer.put((byte) oneByte);
+    }
+
+    @Override
+    public void write(byte[] buffer, int offset, int count) throws IOException {
+        ensureCanWrite(count);
+        mBuffer.put(buffer, offset, count);
+    }
+
+    /**
+     * Sets {@link #mConnected} to {@code true}.
+     */
+    void setConnected() throws IOException {
+        mConnected = true;
+        if (mBuffer.position() < mInitialContentLength) {
+            throw new ProtocolException("Content received is less than Content-Length");
+        }
+        // Flip the buffer to prepare it for UploadDataProvider read calls.
+        mBuffer.flip();
+    }
+
+    // TODO(xunjieli): implement close().
+
+    /**
+     * Ensures that {@code count} bytes can be written to the internal buffer.
+     */
+    private void ensureCanWrite(int count) throws IOException {
+        if (mInitialContentLength != -1
+                && mBuffer.position() + count > mInitialContentLength) {
+            // Error message is to match that of the default implementation.
+            throw new ProtocolException("exceeded content-length limit of "
+                    + mInitialContentLength + " bytes");
+        }
+        if (mConnected) {
+            throw new IllegalStateException("Cannot write after being connected.");
+        }
+        if (mInitialContentLength != -1 || mBuffer.limit() - mBuffer.position() > count) {
+            // If mInitialContentLength is known or there is enough capacity,
+            // the buffer should not grow.
+            return;
+        }
+        int afterSize = Math.max(mBuffer.capacity() * 2, mBuffer.capacity() + count);
+        ByteBuffer newByteBuffer = ByteBuffer.allocate(afterSize);
+        mBuffer.flip();
+        newByteBuffer.put(mBuffer);
+        mBuffer = newByteBuffer;
+    }
+
+    // Below are UploadDataProvider implementations. Only intended to be used
+    // within Cronet.
+
+    @Override
+    public long getLength() {
+        // This method is supposed to be called just before starting the request.
+        // If content length is not initially passed in, the number of bytes
+        // written will be used as the content length.
+        if (mInitialContentLength == -1) {
+            return mBuffer.position();
+        }
+        return mInitialContentLength;
+    }
+
+    @Override
+    public void read(UploadDataSink uploadDataSink, ByteBuffer byteBuffer) {
+        int oldPos = byteBuffer.position();
+        int availableSpace = byteBuffer.capacity() - byteBuffer.position();
+        if (availableSpace  < mBuffer.limit() - mBuffer.position()) {
+            byteBuffer.put(mBuffer.array(), mBuffer.position(), availableSpace);
+            mBuffer.position(mBuffer.position() + availableSpace);
+        } else {
+            byteBuffer.put(mBuffer);
+        }
+        uploadDataSink.onReadSucceeded(false);
+    }
+
+    @Override
+    public void rewind(UploadDataSink uploadDataSink) {
+        mBuffer.position(0);
+        uploadDataSink.onRewindSucceeded();
+    }
+}