[Cronet] Implement batch read in CronetInputStream

components/cronet/android/java/src/org/chromium/net/urlconnection/CronetInputStream.java

 // Copyright 2014 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 java.io.IOException;
 import java.io.InputStream;
 import java.nio.ByteBuffer;
 
@@ skipping 22 matching lines @@
                 && (mBuffer == null || !mBuffer.hasRemaining())) {
             // Requests more data from CronetHttpURLConnection.
             mBuffer = mHttpURLConnection.getMoreData();
         }
         if (mBuffer != null && mBuffer.hasRemaining()) {
             return mBuffer.get() & 0xFF;
         }
         return -1;
     }
 
+    @Override
+    public int read(byte[] buffer, int byteOffset, int byteCount) throws IOException {

[mmenke, 2015/03/05 19:24:46]

Should our argument names match the official spec? 
http://docs.oracle.com/javase/7/docs/api/java/io/InputStream.html#read(byte[]...

[mmenke, 2015/03/05 19:24:46]

Maybe:

if (byteCount == 0)
  return 0;

[xunjieli, 2015/03/05 20:55:13]

Done.

[xunjieli, 2015/03/05 20:55:13]

I am following the Android specs at
http://developer.android.com/reference/java/io/InputStream.html

+        if (!mResponseDataCompleted && (mBuffer == null || !mBuffer.hasRemaining())) {
+            // Requests more data from CronetHttpURLConnection.
+            mBuffer = mHttpURLConnection.getMoreData();
+        }

[mmenke, 2015/03/05 19:24:46]

Suggest turning this block into a private method, since it also appears in
read().  GetMoreDataIfNeeded, or EnsureHasData, or somesuch.

[xunjieli, 2015/03/05 20:55:13]

Done.

+        if (mBuffer != null && mBuffer.hasRemaining()) {
+            int oldPosition = mBuffer.position();
+            mBuffer.get(
+                    buffer, byteOffset, Math.min(mBuffer.limit() - mBuffer.position(), byteCount));
+            return mBuffer.position() - oldPosition;

[mmenke, 2015/03/05 19:24:46]

Is there any case where this is different from the Math.min result?  If not,
seems like you should just replace oldPosition with that.

[xunjieli, 2015/03/05 20:55:13]

Done. Thanks!

+        }
+        return -1;
+    }
+
     void setResponseDataCompleted() {
         mResponseDataCompleted = true;
     }
 }