Audio/video data streaming over shared memory.

chromecast/media/cma/ipc_streamer/coded_frame_provider_host.cc

+// Copyright 2014 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 "chromecast/media/cma/ipc_streamer/coded_frame_provider_host.h"
+
+#include "base/bind.h"
+#include "base/callback_helpers.h"
+#include "chromecast/media/cma/base/decoder_buffer_base.h"
+#include "chromecast/media/cma/ipc/media_message.h"
+#include "chromecast/media/cma/ipc/media_message_fifo.h"
+#include "chromecast/media/cma/ipc/media_message_type.h"
+#include "chromecast/media/cma/ipc_streamer/audio_decoder_config_marshaller.h"
+#include "chromecast/media/cma/ipc_streamer/decoder_buffer_base_marshaller.h"
+#include "chromecast/media/cma/ipc_streamer/video_decoder_config_marshaller.h"
+#include "media/base/buffers.h"
+#include "media/base/decrypt_config.h"
+
+namespace chromecast {
+namespace media {
+
+CodedFrameProviderHost::CodedFrameProviderHost(
+    scoped_ptr<MediaMessageFifo> media_message_fifo)
+  : fifo_(media_message_fifo.Pass()),
+    weak_factory_(this),
+    weak_this_(weak_factory_.GetWeakPtr()) {
+  thread_checker_.DetachFromThread();
+}
+
+CodedFrameProviderHost::~CodedFrameProviderHost() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+}
+
+void CodedFrameProviderHost::Read(const ReadCB& read_cb) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  // Cannot be called if there is already a pending read.
+  DCHECK(read_cb_.is_null());
+  read_cb_ = read_cb;
+
+  ReadMessages();
+}
+
+void CodedFrameProviderHost::Flush(const base::Closure& flush_cb) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  audio_config_ = ::media::AudioDecoderConfig();
+  video_config_ = ::media::VideoDecoderConfig();
+  read_cb_.Reset();
+  fifo_->Flush();
+  flush_cb.Run();
+}
+
+void CodedFrameProviderHost::OnFifoWriteEvent() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  ReadMessages();
+}
+
+base::Closure CodedFrameProviderHost::GetFifoWriteEventCb() {
+  return base::Bind(&CodedFrameProviderHost::OnFifoWriteEvent, weak_this_);
+}
+
+void CodedFrameProviderHost::ReadMessages() {
+  // Read messages until a frame is provided (i.e. not just the audio/video
+  // configurations).
+  while (!read_cb_.is_null()) {
+    scoped_ptr<MediaMessage> msg(fifo_->Pop());
+    if (!msg)
+      break;
+
+    if (msg->type() == PaddingMediaMsg) {
+      // Ignore the message.
+    } else if (msg->type() == AudioConfigMediaMsg) {
+      audio_config_ = AudioDecoderConfigMarshaller::Read(msg.get());
+    } else if (msg->type() == VideoConfigMediaMsg) {
+      video_config_ = VideoDecoderConfigMarshaller::Read(msg.get());
+    } else if (msg->type() == FrameMediaMsg) {
+      scoped_refptr<DecoderBufferBase> buffer =
+          DecoderBufferBaseMarshaller::Read(msg.Pass());
+      base::ResetAndReturn(&read_cb_).Run(
+          buffer, audio_config_, video_config_);
+      audio_config_ = ::media::AudioDecoderConfig();
+      video_config_ = ::media::VideoDecoderConfig();
+    } else {
+      // Receiving an unexpected message.
+      // Possible use case (except software bugs): the renderer process has
+      // been compromised and an invalid message value has been written to
+      // the fifo. Crash the browser process in this case to avoid further
+      // security implications (so do not use NOTREACHED which crashes only
+      // in debug builds).
+      LOG(FATAL) << "Unknown media message";
+    }
+  }
+}
+
+}  // namespace media
+}  // namespace chromecast