Implement audio proxy for Pepper.

In addition to the basic proxying, this required some changes to the dispatcher
and process infrastructure to get the handles of the processes available when
I need them so I can duplicate the shared memory handles properly into the
different processes.

TEST=none
BUG=none
Review URL: http://codereview.chromium.org/4985001

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@68026 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 187 insertions, 0 deletions

diff --git a/ppapi/shared_impl/DEPS b/ppapi/shared_impl/DEPS
new file mode 100644
index 0000000..84fea55
--- /dev/null
+++ b/ppapi/shared_impl/DEPS
@@ -0,0 +1,4 @@
+include_rules = [
+  "+base",
+  "-ppapi/cpp",
+]
diff --git a/ppapi/shared_impl/README.txt b/ppapi/shared_impl/README.txt
new file mode 100644
index 0000000..71ff8d6
--- /dev/null
+++ b/ppapi/shared_impl/README.txt
@@ -0,0 +1,2 @@
+This directory contains implementation code for PPAPI that needs to be shared
+between the backend implemntation in the renderer and in the proxy.
diff --git a/ppapi/shared_impl/audio_impl.cc b/ppapi/shared_impl/audio_impl.cc
new file mode 100644
index 0000000..83b73f6
--- /dev/null
+++ b/ppapi/shared_impl/audio_impl.cc
@@ -0,0 +1,96 @@
+// Copyright (c) 2010 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 "ppapi/shared_impl/audio_impl.h"
+
+#include "base/logging.h"
+
+namespace pp {
+namespace shared_impl {
+
+AudioImpl::AudioImpl()
+    : playing_(false),
+      shared_memory_size_(0),
+      callback_(NULL),
+      user_data_(NULL) {
+}
+
+AudioImpl::~AudioImpl() {
+  // Closing the socket causes the thread to exit - wait for it.
+  socket_->Close();
+  if (audio_thread_.get()) {
+    audio_thread_->Join();
+    audio_thread_.reset();
+  }
+}
+
+void AudioImpl::SetCallback(PPB_Audio_Callback callback, void* user_data) {
+  callback_ = callback;
+  user_data_ = user_data;
+}
+
+void AudioImpl::SetStartPlaybackState() {
+  DCHECK(!playing_);
+  DCHECK(!audio_thread_.get());
+
+  // If the socket doesn't exist, that means that the plugin has started before
+  // the browser has had a chance to create all the shared memory info and
+  // notify us. This is a common case. In this case, we just set the playing_
+  // flag and the playback will automatically start when that data is available
+  // in SetStreamInfo.
+  if (callback_ && socket_.get())
+    StartThread();
+  playing_ = true;
+}
+
+void AudioImpl::SetStopPlaybackState() {
+  DCHECK(playing_);
+
+  if (audio_thread_.get()) {
+    audio_thread_->Join();
+    audio_thread_.reset();
+  }
+  playing_ = false;
+}
+
+void AudioImpl::SetStreamInfo(base::SharedMemoryHandle shared_memory_handle,
+                              size_t shared_memory_size,
+                              base::SyncSocket::Handle socket_handle) {
+  socket_.reset(new base::SyncSocket(socket_handle));
+  shared_memory_.reset(new base::SharedMemory(shared_memory_handle, false));
+  shared_memory_size_ = shared_memory_size;
+
+  if (callback_) {
+    shared_memory_->Map(shared_memory_size_);
+
+    // In common case StartPlayback() was called before StreamCreated().
+    if (playing_)
+      StartThread();
+  }
+}
+
+void AudioImpl::StartThread() {
+  DCHECK(callback_);
+  DCHECK(!audio_thread_.get());
+  audio_thread_.reset(new base::DelegateSimpleThread(
+      this, "plugin_audio_thread"));
+  audio_thread_->Start();
+}
+
+void AudioImpl::Run() {
+  int pending_data;
+  void* buffer = shared_memory_->memory();
+
+  while (sizeof(pending_data) ==
+      socket_->Receive(&pending_data, sizeof(pending_data)) &&
+      pending_data >= 0) {
+    // Exit the thread on pause.
+    if (pending_data < 0)
+      return;
+    callback_(buffer, shared_memory_size_, user_data_);
+  }
+}
+
+}  // namespace shared_impl
+}  // namespace pp
diff --git a/ppapi/shared_impl/audio_impl.h b/ppapi/shared_impl/audio_impl.h
new file mode 100644
index 0000000..b4cb077
--- /dev/null
+++ b/ppapi/shared_impl/audio_impl.h
@@ -0,0 +1,85 @@
+// Copyright (c) 2010 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.
+
+#ifndef PPAPI_SHARED_IMPL_AUDIO_IMPL_H_
+#define PPAPI_SHARED_IMPL_AUDIO_IMPL_H_
+
+#include "base/scoped_ptr.h"
+#include "base/simple_thread.h"
+#include "base/shared_memory.h"
+#include "base/sync_socket.h"
+#include "ppapi/c/dev/ppb_audio_dev.h"
+
+namespace pp {
+namespace shared_impl {
+
+// Implements the logic to map shared memory and run the audio thread signaled
+// from the sync socket. Both the proxy and the renderer implementation use
+// this code.
+class AudioImpl : public base::DelegateSimpleThread::Delegate {
+ public:
+  AudioImpl();
+  virtual ~AudioImpl();
+
+  bool playing() const { return playing_; }
+
+  // Sets the callback information that the background thread will use. This
+  // is optional. Without a callback, the thread will not be run. This
+  // non-callback mode is used in the renderer with the proxy, since the proxy
+  // handles the callback entirely within the plugin process.
+  void SetCallback(PPB_Audio_Callback callback, void* user_data);
+
+  // Configures the current state to be playing or not. The caller is
+  // responsible for ensuring the new state is the opposite of the current one.
+  //
+  // This is the implementation for PPB_Audio.Start/StopPlayback, except that
+  // it does not actually notify the audio system to stop playback, it just
+  // configures our object to stop generating callbacks. The actual stop
+  // playback request will be done in the derived classes and will be different
+  // from the proxy and the renderer.
+  void SetStartPlaybackState();
+  void SetStopPlaybackState();
+
+  // Sets the shared memory and socket handles. This will automatically start
+  // playback if we're currently set to play.
+  void SetStreamInfo(base::SharedMemoryHandle shared_memory_handle,
+                     size_t shared_memory_size,
+                     base::SyncSocket::Handle socket_handle);
+
+ private:
+  // Starts execution of the audio thread.
+  void StartThread();
+
+  // DelegateSimpleThread::Delegate implementation. Run on the audio thread.
+  void Run();
+
+  // True if playing the stream.
+  bool playing_;
+
+  // Socket used to notify us when audio is ready to accept new samples. This
+  // pointer is created in StreamCreated().
+  scoped_ptr<base::SyncSocket> socket_;
+
+  // Sample buffer in shared memory. This pointer is created in
+  // StreamCreated(). The memory is only mapped when the audio thread is
+  // created.
+  scoped_ptr<base::SharedMemory> shared_memory_;
+
+  // The size of the sample buffer in bytes.
+  size_t shared_memory_size_;
+
+  // When the callback is set, this thread is spawned for calling it.
+  scoped_ptr<base::DelegateSimpleThread> audio_thread_;
+
+  // Callback to call when audio is ready to accept new samples.
+  PPB_Audio_Callback callback_;
+
+  // User data pointer passed verbatim to the callback function.
+  void* user_data_;
+};
+
+}  // namespace shared_impl
+}  // namespace pp
+
+#endif  // PPAPI_SHARED_IMPL_AUDIO_IMPL_H_