Add video decoding methods in Decryptor and add DecryptingVideoDecoder.

media/filters/decrypting_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/decrypting_video_decoder.h"
+
+#include "base/bind.h"
+#include "base/callback_helpers.h"
+#include "base/location.h"
+#include "base/message_loop_proxy.h"
+#include "media/base/decoder_buffer.h"
+#include "media/base/decryptor.h"
+#include "media/base/demuxer_stream.h"
+#include "media/base/pipeline.h"
+#include "media/base/video_decoder_config.h"
+#include "media/base/video_frame.h"
+
+namespace media {
+
+DecryptingVideoDecoder::DecryptingVideoDecoder(
+    const MessageLoopFactoryCB& message_loop_factory_cb,
+    Decryptor* decryptor)
+    : message_loop_factory_cb_(message_loop_factory_cb),
+      message_loop_(NULL),

[scherkus (not reviewing), 2012/10/02 19:45:41]

nit: remove

[xhwang, 2012/10/03 02:15:08]

Done.

+      state_(kUninitialized),
+      decryptor_(decryptor) {
+}
+
+void DecryptingVideoDecoder::Initialize(
+    const scoped_refptr<DemuxerStream>& stream,
+    const PipelineStatusCB& status_cb,
+    const StatisticsCB& statistics_cb) {
+  DCHECK(!message_loop_);
+  message_loop_ = base::ResetAndReturn(&message_loop_factory_cb_).Run();
+  message_loop_->PostTask(FROM_HERE, base::Bind(
+      &DecryptingVideoDecoder::DoInitialize, this,
+      stream, status_cb, statistics_cb));
+}
+
+void DecryptingVideoDecoder::Read(const ReadCB& read_cb) {
+  // Complete operation asynchronously on different stack of execution as per
+  // the API contract of VideoDecoder::Read()
+  message_loop_->PostTask(FROM_HERE, base::Bind(
+      &DecryptingVideoDecoder::DoRead, this, read_cb));
+}
+
+void DecryptingVideoDecoder::Reset(const base::Closure& closure) {
+  if (!message_loop_->BelongsToCurrentThread()) {
+    message_loop_->PostTask(FROM_HERE, base::Bind(
+        &DecryptingVideoDecoder::Reset, this, closure));
+    return;
+  }
+
+  DCHECK_NE(state_, kUninitialized);
+  DCHECK(stop_cb_.is_null());  // No Reset() during pending Stop().
+  DCHECK(reset_cb_.is_null());
+  reset_cb_ = closure;
+
+  decryptor_->CancelDecryptAndDecodeVideo();
+
+  // Reset() cannot complete if the read callback is still pending.
+  // Defer the resetting process in this case. The |reset_cb_| will be fired
+  // after the read callback is fired (see DoDecryptAndDecodeBuffer() and

[ddorwin, 2012/10/02 06:10:41]

nit: Might be cleaner to use a dash instead of parens. Below too.

[xhwang, 2012/10/03 02:15:08]

Done.

+  // DoDeliverFrame()).
+  if (!read_cb_.is_null())
+    return;
+
+  DoReset();
+}
+
+void DecryptingVideoDecoder::Stop(const base::Closure& closure) {
+  if (!message_loop_->BelongsToCurrentThread()) {
+    message_loop_->PostTask(FROM_HERE, base::Bind(
+        &DecryptingVideoDecoder::Stop, this, closure));
+    return;
+  }
+
+  DCHECK(stop_cb_.is_null());
+  stop_cb_ = closure;
+
+  decryptor_->StopVideoDecoder();
+
+  // Stop() cannot complete if the read callback is still pending.
+  // Defer the stopping process in this case. The |stop_cb_| will be fired after
+  // the read callback is fired (see DoDecryptAndDecodeBuffer() and
+  // DoDeliverFrame()).

[scherkus (not reviewing), 2012/10/02 19:45:41]

hmm.. is it worth mentioning that a pending reset_cb_ could happen?

it caught me off guard when I saw us executing reset_cb_ in our stop handling
code

[xhwang, 2012/10/03 02:15:08]

Done. Also fixed a bug that stopping during initialization won't block if
init_cb is not returned.

+  if (!read_cb_.is_null())
+    return;
+
+  DoStop();
+}
+
+DecryptingVideoDecoder::~DecryptingVideoDecoder() {
+  DCHECK_EQ(state_, kUninitialized);
+}
+
+void DecryptingVideoDecoder::DoInitialize(
+    const scoped_refptr<DemuxerStream>& stream,
+    const PipelineStatusCB& status_cb,
+    const StatisticsCB& statistics_cb) {
+  DCHECK(message_loop_->BelongsToCurrentThread());
+  DCHECK(stream);
+  const VideoDecoderConfig& config = stream->video_decoder_config();
+  if (!config.IsValidConfig()) {
+    DLOG(ERROR) << "Invalid video stream config: "
+                << config.AsHumanReadableString();
+    status_cb.Run(PIPELINE_ERROR_DECODE);
+    return;
+  }
+
+  // DecryptingVideoDecoder only accepts potentially encrypted stream.
+  if (!config.is_encrypted()) {
+    status_cb.Run(DECODER_ERROR_NOT_SUPPORTED);
+    return;
+  }
+
+  DCHECK(!demuxer_stream_);
+  demuxer_stream_ = stream;
+  statistics_cb_ = statistics_cb;
+
+  DCHECK(decryptor_);
+  decryptor_->InitializeVideoDecoder(

[scherkus (not reviewing), 2012/10/02 19:45:41]

style nit: move "config, base::Bind(" here then drop rest of params on next line

[xhwang, 2012/10/03 02:15:08]

Done.

+      config,
+      base::Bind(&DecryptingVideoDecoder::OnDecoderInitialized, this,
+                 status_cb));
+}
+
+void DecryptingVideoDecoder::OnDecoderInitialized(
+    const PipelineStatusCB& status_cb,
+    bool success) {
+  if (!message_loop_->BelongsToCurrentThread()) {
+    message_loop_->PostTask(FROM_HERE, base::Bind(
+        &DecryptingVideoDecoder::OnDecoderInitialized, this,
+        status_cb, success));
+    return;
+  }
+
+  DCHECK(!status_cb.is_null());
+
+  if (!success) {
+    status_cb.Run(DECODER_ERROR_NOT_SUPPORTED);
+    return;
+  }
+
+  // Success!
+  state_ = kNormal;
+  status_cb.Run(PIPELINE_OK);
+}
+
+void DecryptingVideoDecoder::DoRead(const ReadCB& read_cb) {
+  DCHECK(message_loop_->BelongsToCurrentThread());
+  DCHECK(!read_cb.is_null());
+  CHECK_NE(state_, kUninitialized);
+  CHECK(read_cb_.is_null()) << "Overlapping decodes are not supported.";
+
+  // Return empty frames if decoding has finished.
+  if (state_ == kDecodeFinished) {
+    read_cb.Run(kOk, VideoFrame::CreateEmptyFrame());
+    return;
+  }
+
+  read_cb_ = read_cb;
+  ReadFromDemuxerStream();
+}
+
+void DecryptingVideoDecoder::ReadFromDemuxerStream() {
+  DCHECK(message_loop_->BelongsToCurrentThread());
+  DCHECK_EQ(state_, kNormal);
+  DCHECK(!read_cb_.is_null());
+
+  demuxer_stream_->Read(
+      base::Bind(&DecryptingVideoDecoder::DecryptAndDecodeBuffer, this));
+}
+
+void DecryptingVideoDecoder::DecryptAndDecodeBuffer(
+    DemuxerStream::Status status,
+    const scoped_refptr<DecoderBuffer>& buffer) {
+  // In theory, we don't need to force post the task here, because we do a
+  // force task post in DeliverFrame(). Therefore, even if
+  // demuxer_stream_->Read() execute the read callback on the same execution
+  // stack we are still fine. But it looks like a force post task makes the
+  // logic more understandable and manageable, so why not?
+  message_loop_->PostTask(FROM_HERE, base::Bind(
+      &DecryptingVideoDecoder::DoDecryptAndDecodeBuffer, this,
+      status, buffer));
+}
+
+void DecryptingVideoDecoder::DoDecryptAndDecodeBuffer(
+    DemuxerStream::Status status,
+    const scoped_refptr<DecoderBuffer>& buffer) {
+  DCHECK(message_loop_->BelongsToCurrentThread());
+  DCHECK_EQ(state_, kNormal);
+  DCHECK(!read_cb_.is_null());
+  DCHECK_EQ(!!buffer, status == DemuxerStream::kOk) << status;

[scherkus (not reviewing), 2012/10/02 19:45:41]

we decided against !! style -- just compare against NULL

[xhwang, 2012/10/03 02:15:08]

Done.

+
+  if (!stop_cb_.is_null()) {
+    base::ResetAndReturn(&read_cb_).Run(kOk, NULL);
+    if (!reset_cb_.is_null())
+      DoReset();
+
+    DoStop();
+    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) {
+    // TODO(xhwang): Add config change support.
+    base::ResetAndReturn(&read_cb_).Run(kDecodeError, NULL);
+    return;
+  }
+
+  DCHECK_EQ(status, DemuxerStream::kOk);
+  DCHECK(buffer);

[scherkus (not reviewing), 2012/10/02 19:45:41]

dcheck not useful

[xhwang, 2012/10/03 02:15:08]

Done.

+
+  decryptor_->DecryptAndDecodeVideo(
+      buffer, base::Bind(&DecryptingVideoDecoder::DeliverFrame, this,
+                         buffer->GetDataSize()));
+}
+
+void DecryptingVideoDecoder::DeliverFrame(
+    int buffer_size,
+    Decryptor::Status status,
+    const scoped_refptr<VideoFrame>& frame) {
+  // We need to force task post here because the VideoDecodeCB can be executed
+  // synchronously in Reset()/Stop(). Instead of using more complicated logic in
+  // those function to fix it, why not force task post here to make everything
+  // simple and clear?
+  message_loop_->PostTask(FROM_HERE, base::Bind(
+      &DecryptingVideoDecoder::DoDeliverFrame, this,
+      buffer_size, status, frame));
+}
+
+void DecryptingVideoDecoder::DoDeliverFrame(
+    int buffer_size,
+    Decryptor::Status status,
+    const scoped_refptr<VideoFrame>& frame) {
+  DCHECK(message_loop_->BelongsToCurrentThread());
+  DCHECK_EQ(state_, kNormal);
+  DCHECK(!read_cb_.is_null());
+
+  if (!stop_cb_.is_null()) {
+    base::ResetAndReturn(&read_cb_).Run(kOk, NULL);
+    if (!reset_cb_.is_null())
+      DoReset();
+
+    DoStop();
+    return;
+  }
+
+  if (!reset_cb_.is_null()) {
+    base::ResetAndReturn(&read_cb_).Run(kOk, NULL);
+    DoReset();
+    return;
+  }
+
+  if (status == Decryptor::kNoKey || status == Decryptor::kError) {
+    DCHECK(!frame);
+    state_ = kDecodeFinished;
+    base::ResetAndReturn(&read_cb_).Run(kDecodeError, NULL);
+    return;
+  }
+
+  // The buffer has been accepted by the decoder, let's report statistics.
+  if (buffer_size) {
+    PipelineStatistics statistics;
+    statistics.video_bytes_decoded = buffer_size;
+    statistics_cb_.Run(statistics);
+  }
+
+  if (status == Decryptor::kNeedMoreData) {
+    DCHECK(!frame);
+    ReadFromDemuxerStream();
+    return;
+  }
+
+  DCHECK_EQ(status, Decryptor::kSuccess);
+  DCHECK(frame);

[scherkus (not reviewing), 2012/10/02 19:45:41]

dcheck not useful

[xhwang, 2012/10/03 02:15:08]

Done.

+  if (frame->IsEndOfStream())
+    state_ = kDecodeFinished;
+
+  base::ResetAndReturn(&read_cb_).Run(kOk, frame);
+}
+
+void DecryptingVideoDecoder::DoReset() {
+  DCHECK(read_cb_.is_null());
+  DCHECK_NE(state_, kUninitialized);
+  state_ = kNormal;
+  base::ResetAndReturn(&reset_cb_).Run();
+}
+
+void DecryptingVideoDecoder::DoStop() {
+  DCHECK(read_cb_.is_null());
+  state_ = kUninitialized;
+  base::ResetAndReturn(&stop_cb_).Run();
+}
+
+}  // namespace media