[Cronet] When connection is disconnected, InputStream#read should give an exception

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;
 
 /**
  * An InputStream that is used by {@link CronetHttpURLConnection} to request
  * data from the network stack as needed.
  */
 class CronetInputStream extends InputStream {
     private final CronetHttpURLConnection mHttpURLConnection;
     // Indicates whether listener's onSucceeded or onFailed callback is invoked.
     private boolean mResponseDataCompleted;
     private ByteBuffer mBuffer;
+    private IOException mException;
 
     private static final int READ_BUFFER_SIZE = 32 * 1024;
 
     /**
      * Constructs a CronetInputStream.
      * @param httpURLConnection the CronetHttpURLConnection that is associated
      *            with this InputStream.
      */
     public CronetInputStream(CronetHttpURLConnection httpURLConnection) {
         mHttpURLConnection = httpURLConnection;
@@ skipping 21 matching lines @@
             int bytesRead = Math.min(mBuffer.limit() - mBuffer.position(), byteCount);
             mBuffer.get(buffer, byteOffset, bytesRead);
             return bytesRead;
         }
         return -1;
     }
 
     /**
      * Called by {@link CronetHttpURLConnection} to notify that the entire
      * response body has been read.
+     * @param exception if not null, it is the exception to throw when caller

[pauljensen, 2015/11/10 15:55:21]

here and elsewhere:
null->{@code null}

[xunjieli, 2015/11/10 16:16:59]

Done.

+     *            tries to read more data than what is buffered.
      */
-    void setResponseDataCompleted() {
+    void setResponseDataCompleted(IOException exception) {
+        mException = exception;
         mResponseDataCompleted = true;
         // Nothing else to read, so can free the buffer.
         mBuffer = null;
     }
 
     private void getMoreDataIfNeeded() throws IOException {
-        if (!mResponseDataCompleted && !hasUnreadData()) {
+        if (mResponseDataCompleted) {
+            if (mException != null) {
+                throw mException;
+            }
+            return;
+        }
+        if (!hasUnreadData()) {
             // Allocate read buffer if needed.
             if (mBuffer == null) {
                 mBuffer = ByteBuffer.allocateDirect(READ_BUFFER_SIZE);
             }
             mBuffer.clear();
 
             // Requests more data from CronetHttpURLConnection.
             mHttpURLConnection.getMoreData(mBuffer);
+            if (mException != null) {
+                throw mException;
+            }
             if (mBuffer != null) {
                 mBuffer.flip();
             }
         }
     }
 
     /**
      * Returns whether {@link #mBuffer} has unread data.
      */
     private boolean hasUnreadData() {
         return mBuffer != null && mBuffer.hasRemaining();
     }
 }