Introduce VideoFrameStream, the video frame provider in media pipeline.

media/filters/video_frame_stream.cc

Index: media/filters/video_frame_stream.cc
diff --git a/media/filters/video_frame_stream.cc b/media/filters/video_frame_stream.cc
new file mode 100644
index 0000000000000000000000000000000000000000..857a6e83908025963aa854b3ed9a19ba38ebeae2
--- /dev/null
+++ b/media/filters/video_frame_stream.cc
@@ -0,0 +1,206 @@
+// Copyright (c) 2013 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/video_frame_stream.h"
+
+#include "base/bind.h"
+#include "base/callback_helpers.h"
+#include "base/location.h"
+#include "base/logging.h"
+#include "base/message_loop_proxy.h"
+#include "media/base/bind_to_loop.h"
+#include "media/base/demuxer_stream.h"
+#include "media/base/video_decoder_config.h"
+#include "media/filters/decrypting_demuxer_stream.h"
+#include "media/filters/video_decoder_selector.h"
+
+namespace media {
+
+VideoFrameStream::VideoFrameStream(
+    const scoped_refptr<base::MessageLoopProxy>& message_loop,
+    const SetDecryptorReadyCB& set_decryptor_ready_cb)
+    : message_loop_(message_loop),
+      weak_factory_(this),
+      state_(UNINITIALIZED),
+      set_decryptor_ready_cb_(set_decryptor_ready_cb) {
+}
+
+VideoFrameStream::~VideoFrameStream() {
+  DCHECK(state_ == UNINITIALIZED || state_ == STOPPED);

[scherkus (not reviewing), 2013/03/22 01:02:40]

emit state

[xhwang, 2013/03/22 07:23:28]

Done.

+}
+
+void VideoFrameStream::Initialize(const scoped_refptr<DemuxerStream>& stream,
+                                  const VideoDecoderList& decoders,
+                                  const StatisticsCB& statistics_cb,
+                                  const InitCB& init_cb) {
+  DCHECK(message_loop_->BelongsToCurrentThread());
+  DCHECK_EQ(state_, UNINITIALIZED);
+
+  weak_this_ = weak_factory_.GetWeakPtr();
+
+  DCHECK(init_cb_.is_null());
+  DCHECK(!init_cb.is_null());
+  init_cb_ = init_cb;
+
+  scoped_ptr<VideoDecoderSelector> decoder_selector(
+      new VideoDecoderSelector(message_loop_,
+                               decoders,
+                               set_decryptor_ready_cb_));
+
+  // To avoid calling |decoder_selector| methods and passing ownership of
+  // |decoder_selector| in the same line.
+  VideoDecoderSelector* decoder_selector_ptr = decoder_selector.get();
+
+  decoder_selector_ptr->SelectVideoDecoder(
+      stream,
+      statistics_cb,
+      base::Bind(&VideoFrameStream::OnDecoderSelected, weak_this_,
+                 base::Passed(&decoder_selector)));
+}
+
+void VideoFrameStream::ReadFrame(const VideoDecoder::ReadCB& read_cb) {
+  DCHECK(message_loop_->BelongsToCurrentThread());
+  DCHECK_EQ(state_, NORMAL);
+  // No two reads in the flight at any time.
+  DCHECK(read_cb_.is_null());
+  // No read during resetting or stopping process.
+  DCHECK(reset_cb_.is_null());
+  DCHECK(stop_cb_.is_null());
+
+  read_cb_ = read_cb;
+
+  decoder_->Read(base::Bind(&VideoFrameStream::OnFrameRead, weak_this_));
+}
+
+void VideoFrameStream::Reset(const base::Closure& closure) {
+  DCHECK(message_loop_->BelongsToCurrentThread());
+  DCHECK_EQ(state_, NORMAL);
+  DCHECK(reset_cb_.is_null());
+  DCHECK(stop_cb_.is_null());
+
+  reset_cb_ = closure;
+
+  // We may or may not have pending read, but we'll start to reset everything
+  // regardless.
+
+  if (decrypting_demuxer_stream_) {
+    decrypting_demuxer_stream_->Reset(base::Bind(
+        &VideoFrameStream::ResetDecoder, weak_this_));
+    return;
+  }
+
+  DCHECK(decoder_) << "Reset() without successfully initialized a decoder.";

[scherkus (not reviewing), 2013/03/22 01:02:40]

not needed -- we'll crash

[xhwang, 2013/03/22 07:23:28]

Done.

+  ResetDecoder();
+}
+
+void VideoFrameStream::Stop(const base::Closure& closure) {
+  DCHECK(message_loop_->BelongsToCurrentThread());
+  // TODO(xhwang): This is necessary. But it would be interesting to see if we
+  // ever hit.

[scherkus (not reviewing), 2013/03/22 01:02:40]

not sure I understand this TODO

[xhwang, 2013/03/22 07:23:28]

Updated.

+  DCHECK_NE(state_, STOPPED);
+  DCHECK(stop_cb_.is_null());
+
+  stop_cb_ = closure;
+
+  // The stopping process will be continued after all of the following pending

[scherkus (not reviewing), 2013/03/22 01:02:40]

s/stopping process will be continued/stopping will continue/

[xhwang, 2013/03/22 07:23:28]

Done.

+  // callbacks (if they are not null) are satisfied.
+  // TODO(xhwang): Now we cannot stop the initialization process through
+  // VideoDecoderSelector. Fix this. See: http://crbug.com/222054
+  if (!init_cb_.is_null())
+    return;
+
+  // We may or may not have pending read and/or pending reset, but we'll start
+  // to stop everything regardless.
+
+  if (decrypting_demuxer_stream_) {
+    decrypting_demuxer_stream_->Reset(base::Bind(
+        &VideoFrameStream::StopDecoder, weak_this_));
+    return;
+  }
+
+  if (decoder_) {
+    StopDecoder();
+    return;
+  }
+
+  state_ = STOPPED;
+  // BindToCurrentLoop() force posts the callback.
+  BindToCurrentLoop(closure).Run();

[scherkus (not reviewing), 2013/03/22 01:02:40]

what do you think about using "message_loop_->PostTask(closure)" instead?

[xhwang, 2013/03/22 07:23:28]

Done.

+}
+
+void VideoFrameStream::OnDecoderSelected(
+    scoped_ptr<VideoDecoderSelector> decoder_selector,
+    const scoped_refptr<VideoDecoder>& selected_decoder,
+    const scoped_refptr<DecryptingDemuxerStream>& decrypting_demuxer_stream) {
+  DCHECK(message_loop_->BelongsToCurrentThread());
+  DCHECK_EQ(state_, UNINITIALIZED);
+  DCHECK(!init_cb_.is_null());
+
+  if (!selected_decoder) {
+    state_ = UNINITIALIZED;
+    base::ResetAndReturn(&init_cb_).Run(false, false);
+  } else {
+    decoder_ = selected_decoder;
+    decrypting_demuxer_stream_ = decrypting_demuxer_stream;
+    state_ = NORMAL;
+    base::ResetAndReturn(&init_cb_).Run(true, decoder_->HasAlpha());
+  }
+
+  // Stop() called during initialization.
+  if (!stop_cb_.is_null()) {
+    Stop(base::ResetAndReturn(&stop_cb_));
+    return;
+  }
+}
+
+void VideoFrameStream::OnFrameRead(const VideoDecoder::Status status,
+                                   const scoped_refptr<VideoFrame>& frame) {
+  DCHECK(message_loop_->BelongsToCurrentThread());
+  DCHECK_EQ(state_, NORMAL);
+  DCHECK(!read_cb_.is_null());
+
+  base::ResetAndReturn(&read_cb_).Run(status, frame);
+}
+
+void VideoFrameStream::ResetDecoder() {
+  DCHECK(message_loop_->BelongsToCurrentThread());
+  DCHECK(state_ == NORMAL);

[scherkus (not reviewing), 2013/03/22 01:02:40]

EQ

[xhwang, 2013/03/22 07:23:28]

Done.

+  DCHECK(!reset_cb_.is_null());
+
+  decoder_->Reset(base::Bind(&VideoFrameStream::OnDecoderReset, weak_this_));
+}
+
+void VideoFrameStream::OnDecoderReset() {
+  DCHECK(message_loop_->BelongsToCurrentThread());
+  DCHECK_EQ(state_, NORMAL);
+  // If Reset() was called during pending read, read callback should be fired
+  // before the reset callback is fired.
+  DCHECK(read_cb_.is_null());
+  DCHECK(!reset_cb_.is_null());
+
+  base::ResetAndReturn(&reset_cb_).Run();
+}
+
+void VideoFrameStream::StopDecoder() {
+  DCHECK(message_loop_->BelongsToCurrentThread());
+  DCHECK_EQ(state_, NORMAL);
+  DCHECK(!stop_cb_.is_null());
+
+  decoder_->Stop(base::Bind(&VideoFrameStream::OnDecoderStopped, weak_this_));
+}
+
+void VideoFrameStream::OnDecoderStopped() {
+  DCHECK(message_loop_->BelongsToCurrentThread());
+  DCHECK_EQ(state_, NORMAL);
+  // If Stop() was called during pending read/reset, read/reset callback should
+  // be fired before the stop callback is fired.
+  DCHECK(read_cb_.is_null());
+  DCHECK(reset_cb_.is_null());
+  DCHECK(!stop_cb_.is_null());
+
+  state_ = STOPPED;
+  base::ResetAndReturn(&stop_cb_).Run();
+}
+
+}  // namespace media