Handle config change during pending reset correctly in FFmpegVideoDecoder.

media/filters/ffmpeg_video_decoder.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/filters/ffmpeg_video_decoder.h"
 
 #include <algorithm>
 #include <string>
 
 #include "base/bind.h"
@@ skipping 215 matching lines @@
     const scoped_refptr<DecoderBuffer>& buffer) {
   DCHECK(message_loop_->BelongsToCurrentThread());
   DCHECK_NE(state_, kDecodeFinished);
   DCHECK_EQ(status != DemuxerStream::kOk, !buffer) << status;
 
   if (state_ == kUninitialized)
     return;
 
   DCHECK(!read_cb_.is_null());
 
+  if (status == DemuxerStream::kConfigChanged) {
+    if (!ConfigureDecoder()) {
+      base::ResetAndReturn(&read_cb_).Run(kDecodeError, NULL);
+      state_ = kDecodeFinished;

[acolwell GONE FROM CHROMIUM, 2013/01/03 17:53:31]

Why is this needed now? The Read() shouldn't be called again after kDecodeError
is returned. If anything we should transition to a state that always returns
kDecodeError for all future Read() calls until a Reset() happens.

[xhwang, 2013/01/04 01:28:05]

This transition follows the comment on line 298. I agree that kDecodeFinished
may not be the best option. But that'd be in another CL.

+      if (!reset_cb_.is_null())
+        base::ResetAndReturn(&reset_cb_).Run();
+      return;
+    }
+
+    if (!reset_cb_.is_null()) {

[acolwell GONE FROM CHROMIUM, 2013/01/03 17:53:31]

nit: If you flip the condition here you can reuse the DoReset() code below
instead of duplicating it here.

[xhwang, 2013/01/04 01:28:05]

Done.

+      base::ResetAndReturn(&read_cb_).Run(kOk, NULL);
+      DoReset();
+      return;
+    }
+
+    ReadFromDemuxerStream();
+    return;
+  }
+
   if (!reset_cb_.is_null()) {
     base::ResetAndReturn(&read_cb_).Run(kOk, NULL);
     DoReset();
     return;
   }
 
   if (status == DemuxerStream::kAborted) {
     base::ResetAndReturn(&read_cb_).Run(kOk, NULL);
     return;
   }
 
-  if (status == DemuxerStream::kConfigChanged) {
-    if (!ConfigureDecoder()) {
-      base::ResetAndReturn(&read_cb_).Run(kDecodeError, NULL);
-      return;
-    }
-
-    ReadFromDemuxerStream();
-    return;
-  }
-
   DCHECK_EQ(status, DemuxerStream::kOk);
   DecodeBuffer(buffer);
 }
 
 void FFmpegVideoDecoder::DecodeBuffer(
     const scoped_refptr<DecoderBuffer>& buffer) {
   DCHECK(message_loop_->BelongsToCurrentThread());
   DCHECK_NE(state_, kUninitialized);
   DCHECK_NE(state_, kDecodeFinished);
   DCHECK(reset_cb_.is_null());
@@ skipping 175 matching lines @@
   if (!codec || avcodec_open2(codec_context_, codec, NULL) < 0) {
     ReleaseFFmpegResources();
     return false;
   }
 
   av_frame_ = avcodec_alloc_frame();
   return true;
 }
 
 }  // namespace media