Switch stream creation and closing in Chrome audio rendering from IPC to Mojo

content/browser/media/audio_output_impl.cc

Index: content/browser/media/audio_output_impl.cc
diff --git a/content/browser/media/audio_output_impl.cc b/content/browser/media/audio_output_impl.cc
new file mode 100644
index 0000000000000000000000000000000000000000..6bc17494bc501e0a9ccb78870d4f0a7376770fed
--- /dev/null
+++ b/content/browser/media/audio_output_impl.cc
@@ -0,0 +1,198 @@
+// Copyright 2016 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.
+
+#if defined(OS_WIN)
+#include <windows.h>
+#endif
+
+#include "base/memory/shared_memory.h"
+#include "content/browser/frame_host/render_frame_host_impl.h"
+#include "content/browser/media/audio_output_impl.h"
+#include "content/browser/media/audio_output_stream_impl.h"
+#include "content/browser/renderer_host/render_process_host_impl.h"
+#include "content/public/browser/render_frame_host.h"
+#include "mojo/edk/embedder/embedder.h"
+#include "mojo/public/cpp/system/handle.h"
+#include "mojo/public/cpp/system/platform_handle.h"
+
+namespace content {
+
+namespace {
+
+base::SyncSocket::TransitDescriptor DuplicateSocket(
+    base::SyncSocket::TransitDescriptor socket_descriptor) {
+  base::SyncSocket::TransitDescriptor socket_descriptor_dup;
+
+#if defined(OS_WIN)
+  socket_descriptor_dup = 0;
+  if (!::DuplicateHandle(GetCurrentProcess(),  // hSourceProcessHandle
+                         socket_descriptor,
+                         GetCurrentProcess(),  // hTargetProcessHandle
+                         &socket_descriptor_dup,
+                         0,      // dwDesiredAccess ignored due to SAME_ACCESS
+                         FALSE,  // !bInheritHandle
+                         DUPLICATE_SAME_ACCESS)) {
+    LOG(ERROR) << "Unable to duplicate socket handle.";
+  }
+
+#else
+  socket_descriptor_dup.fd = dup(socket_descriptor.fd);
+#endif
+  return socket_descriptor_dup;
+}
+
+}  // namespace
+
+AudioOutputImpl::AudioOutputImpl(RenderFrameHostImpl* frame,
+                                 media::mojom::AudioOutputRequest request)
+    : frame_(frame), binding_(this) {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+  binding_.Bind(std::move(request));
+}
+
+AudioOutputImpl::~AudioOutputImpl() {
+  for (auto it = create_stream_callbacks_.begin();
+       it != create_stream_callbacks_.end(); ++it) {
+    it->second.reset();
+  }
+  create_stream_callbacks_.clear();
+}
+
+// static
+void AudioOutputImpl::CreateService(RenderFrameHostImpl* frame,
+                                    media::mojom::AudioOutputRequest request) {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+
+  BrowserThread::PostTask(BrowserThread::IO, FROM_HERE,
+                          base::Bind(&AudioOutputImpl::CreateServiceOnIOThread,
+                                     frame, base::Passed(&request)));
+}
+
+// static
+void AudioOutputImpl::CreateServiceOnIOThread(
+    RenderFrameHostImpl* frame,
+    media::mojom::AudioOutputRequest request) {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+
+  new AudioOutputImpl(frame, std::move(request));
+}
+
+void AudioOutputImpl::CreateStream(int stream_id,
+                                   const media::AudioParameters& params,
+                                   const CreateStreamCallback& callback) {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+
+  create_stream_callbacks_.insert(std::make_pair(stream_id, callback));
+  InitAudioRendererHost();
+  if (audio_renderer_host_)
+    audio_renderer_host_->CreateStream(stream_id, frame_->GetRoutingID(),
+                                       params, this);
+}
+
+void AudioOutputImpl::CreateStreamFactory(
+    int stream_id,
+    base::SharedMemory* shared_memory,
+    base::SyncSocket::TransitDescriptor socket_descriptor) {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+
+  auto callback = create_stream_callbacks_.find(stream_id);
+  if (callback == create_stream_callbacks_.end())
+    return;
+
+  media::mojom::AudioOutputStreamPtr stream_ptr =
+      media::mojom::AudioOutputStreamPtr();
+  std::unique_ptr<AudioOutputStreamImpl> stream(
+      new AudioOutputStreamImpl(stream_id, this, mojo::GetProxy(&stream_ptr)));
+  stream_impls_.insert(std::make_pair(stream_id, std::move(stream)));
+
+  base::SharedMemoryHandle shared_memory_handle =
+      base::SharedMemory::DuplicateHandle(shared_memory->handle());
+  if (!base::SharedMemory::IsHandleValid(shared_memory_handle))
+    return;
+  mojo::ScopedSharedBufferHandle shared_buffer_handle =
+      mojo::WrapSharedMemoryHandle(shared_memory_handle,
+                                   shared_memory->requested_size(), false);
+  // The socket that we will send from the browser to the renderer is a
+  // |foreign_socket_| which is a part AudioSyncReader that is owned by
+  // AudioEntry. The socket handle will be closed when the AudioEntry it
+  // belongs to will be closed. However, with mojo and unlike IPC, the
+  // ownership of the handle is transferred to the target process. It's no
+  // longer a valid handle in the sending process and it is an error to try
+  // closing it there. So, if the socket handle is closed when the AudioEntry
+  // is deleted, we will have an error. To fix this error we could just
+  // duplicate the socket and send the duplicate to the renderer. Thus, we
+  // will avoid having an problem when closing the socket.
+  // See https://goo.gl/ACwSfa.
+  base::SyncSocket::TransitDescriptor socket_descriptor_dup =
+      DuplicateSocket(socket_descriptor);
+#if defined(OS_WIN)
+  mojo::ScopedHandle socket_handle =
+      mojo::WrapPlatformFile(socket_descriptor_dup);
+#else
+  mojo::ScopedHandle socket_handle =
+      mojo::WrapPlatformFile(socket_descriptor_dup.fd);
+#endif
+
+  callback->second.Run(stream_id, std::move(stream_ptr),
+                       std::move(shared_buffer_handle),
+                       std::move(socket_handle));
+  callback->second.reset();
+  create_stream_callbacks_.erase(stream_id);
+}
+
+bool AudioOutputImpl::CloseStream(int stream_id) {
+  if (audio_renderer_host_.get())
+    audio_renderer_host_->CloseStream(stream_id);
+
+  if (stream_impls_.erase(stream_id) == 0)
+    return false;
+
+  auto callback = create_stream_callbacks_.find(stream_id);
+
+  if (callback != create_stream_callbacks_.end()) {
+    callback->second.reset();
+    create_stream_callbacks_.erase(stream_id);
+  }
+  return true;
+}
+
+void AudioOutputImpl::ReportErrorAndCloseStream(int stream_id) {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+
+  // Make sure this isn't a stray callback executing after the stream has been
+  // closed, so error notifications aren't sent after clients believe the stream
+  // is closed.
+  auto callback = create_stream_callbacks_.find(stream_id);
+
+  mojo::ScopedSharedBufferHandle shared_buffer_handle =
+      mojo::ScopedSharedBufferHandle(mojo::SharedBufferHandle());
+
+  mojo::ScopedHandle socket_handle = mojo::ScopedHandle(mojo::Handle());
+
+  callback->second.Run(stream_id, media::mojom::AudioOutputStreamPtr(),
+                       std::move(shared_buffer_handle),
+                       std::move(socket_handle));
+
+  if (audio_renderer_host_)
+    audio_renderer_host_->get_audio_log()->OnError(stream_id);
+  CloseStream(stream_id);
+}
+
+void AudioOutputImpl::InitAudioRendererHost() {
+  RenderProcessHost* process = frame_->GetProcess();
+  // It's safe to use static casting of the |process| to RenderProcessHostImpl
+  // outside the tests: there is just RenderProcessHostImpl and
+  // MockRenderProcessHost that inherit from RenderProcessHost and
+  // MockRenderProcessHost is used in just some tests that doesn't involve
+  // AudioOutputImpl. It's also a common practice used in many places to access
+  // RenderProcessHostImpl hidden methods  from RenderProcessHost.
+  // See https://goo.gl/tkKvkd.
+
+  auto host =
+      static_cast<RenderProcessHostImpl*>(process)->audio_renderer_host();
+  if (host.get())
+    audio_renderer_host_ = host;

[Henrik Grunell, 2016/05/30 12:44:56]

If we should surely be able to initialize the ARH here (I think that should be
the case), just set the member directly and CHECK() that it's non-null.

Also, if already set, just return before doing anything else.

+}
+
+}  // namespace content