Returns AVERROR_EOF when FFmpeg is read at the end of file

BUG=18046
TEST=media_unittests --gtest_filter=FFmpegDemuxerTest.ProtocolRead

FFmpeg may read over the size of a file. When it happens we
should return AVERROR_EOF.

Review URL: http://codereview.chromium.org/159679

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@22133 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 19 insertions, 2 deletions

diff --git a/media/filters/ffmpeg_demuxer.cc b/media/filters/ffmpeg_demuxer.cc
index 4ad463a..00e6531 100644
--- a/media/filters/ffmpeg_demuxer.cc
+++ b/media/filters/ffmpeg_demuxer.cc
@@ -304,6 +304,12 @@ int FFmpegDemuxer::Read(int size, uint8* data) {
   if (read_has_failed_)
     return AVERROR_IO;
 
+  // If the read position exceeds the size of the data source. We should return
+  // end-of-file directly.
+  int64 file_size;
+  if (data_source_->GetSize(&file_size) && read_position_ >= file_size)
+    return AVERROR_EOF;
+
   // Asynchronous read from data source.
   data_source_->Read(read_position_, size, data,
                      NewCallback(this, &FFmpegDemuxer::OnReadCompleted));
diff --git a/media/filters/ffmpeg_demuxer_unittest.cc b/media/filters/ffmpeg_demuxer_unittest.cc
index ccd0611..044e8ea 100644
--- a/media/filters/ffmpeg_demuxer_unittest.cc
+++ b/media/filters/ffmpeg_demuxer_unittest.cc
@@ -709,6 +709,8 @@ TEST_F(FFmpegDemuxerTest, ProtocolRead) {
   uint8 kBuffer[1];
   InSequence s;
   // Actions taken in the first read.
+  EXPECT_CALL(*data_source_, GetSize(_))
+      .WillOnce(DoAll(SetArgumentPointee<0>(1024), Return(true)));
   EXPECT_CALL(*data_source_, Read(0, 512, kBuffer, NotNull()))
       .WillOnce(WithArgs<1, 3>(Invoke(&RunCallback)));
   EXPECT_CALL(*demuxer, SignalReadCompleted(512));
@@ -716,25 +718,34 @@ TEST_F(FFmpegDemuxerTest, ProtocolRead) {
       .WillOnce(Return(512));
 
   // Second read.
+  EXPECT_CALL(*data_source_, GetSize(_))
+      .WillOnce(DoAll(SetArgumentPointee<0>(1024), Return(true)));
   EXPECT_CALL(*data_source_, Read(512, 512, kBuffer, NotNull()))
       .WillOnce(WithArgs<1, 3>(Invoke(&RunCallback)));
   EXPECT_CALL(*demuxer, SignalReadCompleted(512));
   EXPECT_CALL(*demuxer, WaitForRead())
       .WillOnce(Return(512));
 
-  // Called during SetPosition().
+  // Third read will fail because it exceeds the file size.
   EXPECT_CALL(*data_source_, GetSize(_))
       .WillOnce(DoAll(SetArgumentPointee<0>(1024), Return(true)));
 
   // This read complete signal is generated when demuxer is stopped.
   EXPECT_CALL(*demuxer, SignalReadCompleted(DataSource::kReadError));
 
+  // First read.
   EXPECT_EQ(512, demuxer->Read(512, kBuffer));
   int64 position;
   EXPECT_TRUE(demuxer->GetPosition(&position));
   EXPECT_EQ(512, position);
+
+  // Second read.
   EXPECT_EQ(512, demuxer->Read(512, kBuffer));
-  EXPECT_FALSE(demuxer->SetPosition(1024));
+  EXPECT_TRUE(demuxer->GetPosition(&position));
+  EXPECT_EQ(1024, position);
+
+  // Third read will get an end-of-file error.
+  EXPECT_EQ(AVERROR_EOF, demuxer->Read(512, kBuffer));
 
   demuxer->Stop();
 }