Fix race condition in media Pipeline::GetMediaTime() after seeking.

media/base/pipeline_impl_unittest.cc

 // Copyright (c) 2012 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.
 
 #include "media/base/pipeline_impl.h"
 
 #include <stddef.h>
 #include <memory>
 #include <utility>
 #include <vector>
@@ skipping 806 matching lines @@
   EXPECT_CALL(*renderer_, GetMediaTime()).WillRepeatedly(Return(kMediaTime));
   EXPECT_EQ(kMediaTime, pipeline_->GetMediaTime());
 
   // Media time should not go backwards even if the renderer returns an
   // errorneous value. PipelineImpl should clamp it to last reported value.
   EXPECT_CALL(*renderer_, GetMediaTime())
       .WillRepeatedly(Return(base::TimeDelta::FromSeconds(1)));
   EXPECT_EQ(kMediaTime, pipeline_->GetMediaTime());
 }
 
+// Seeking posts a task from main thread to media thread to seek the renderer,
+// resetting its internal clock. Calling GetMediaTime() should be safe even
+// when the renderer has not performed the seek (simulated by its continuing
+// to return the pre-seek time). Verifies fix for http://crbug.com/675556
+TEST_F(PipelineImplTest, GetMediaTimeAfterSeek) {
+  CreateAudioStream();
+  MockDemuxerStreamVector streams;
+  streams.push_back(audio_stream());
+  SetDemuxerExpectations(&streams);
+  SetRendererExpectations();
+  StartPipelineAndExpect(PIPELINE_OK);
+
+  // Pipeline should report the same media time returned by the renderer.
+  base::TimeDelta kMediaTime = base::TimeDelta::FromSeconds(2);
+  EXPECT_CALL(*renderer_, GetMediaTime()).WillRepeatedly(Return(kMediaTime));
+  EXPECT_EQ(kMediaTime, pipeline_->GetMediaTime());
+
+  // Seek backward 1 second. Do not run RunLoop to ensure renderer is not yet
+  // notified of the seek (via media thread).
+  base::TimeDelta kSeekTime = kMediaTime - base::TimeDelta::FromSeconds(1);
+  ExpectSeek(kSeekTime, false);
+  pipeline_->Seek(kSeekTime, base::Bind(&CallbackHelper::OnSeek,
+                                        base::Unretained(&callbacks_)));
+
+  // Verify pipeline returns the seek time in spite of renderer returning the
+  // stale media time.
+  EXPECT_EQ(kSeekTime, pipeline_->GetMediaTime());
+  EXPECT_EQ(kMediaTime, renderer_->GetMediaTime());
+
+  // Allow seek task to post to the renderer.
+  base::RunLoop().RunUntilIdle();
+
+  // With seek completed, pipeline should again return the renderer's media time
+  // (as long as media time is moving forward).
+  EXPECT_EQ(kMediaTime, pipeline_->GetMediaTime());
+}
+
 class PipelineTeardownTest : public PipelineImplTest {
  public:
   enum TeardownState {
     kInitDemuxer,
     kInitRenderer,
     kFlushing,
     kSeeking,
     kPlaying,
     kSuspending,
     kSuspended,
@@ skipping 249 matching lines @@
 INSTANTIATE_TEARDOWN_TEST(Error, Seeking);
 INSTANTIATE_TEARDOWN_TEST(Error, Playing);
 INSTANTIATE_TEARDOWN_TEST(Error, Suspending);
 INSTANTIATE_TEARDOWN_TEST(Error, Suspended);
 INSTANTIATE_TEARDOWN_TEST(Error, Resuming);
 
 INSTANTIATE_TEARDOWN_TEST(ErrorAndStop, Playing);
 INSTANTIATE_TEARDOWN_TEST(ErrorAndStop, Suspended);
 
 }  // namespace media