Switch OnMoreData() to use AudioBus.

ppapi/shared_impl/ppb_audio_shared.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 "ppapi/shared_impl/ppb_audio_shared.h"
 
 #include "base/logging.h"
 #include "media/audio/shared_memory_util.h"
 #include "ppapi/shared_impl/ppapi_globals.h"
 
+// Hard coded values from PepperPlatformAudioOutputImpl.
+// TODO(???): PPAPI shouldn't hard code these values for all clients.
+enum { kChannels = 2, kBytesPerSample = 2 };
+
 namespace ppapi {
 
 #if defined(OS_NACL)
 namespace {
 // Because this is static, the function pointers will be NULL initially.
 PP_ThreadFunctions thread_functions;
 }
 #endif  // defined(OS_NACL)
 
 PPB_Audio_Shared::PPB_Audio_Shared()
     : playing_(false),
       shared_memory_size_(0),
 #if defined(OS_NACL)
       thread_id_(0),
       thread_active_(false),
 #endif
       callback_(NULL),
-      user_data_(NULL) {
+      user_data_(NULL),
+      audio_buffer_size_bytes_(0) {
 }
 
 PPB_Audio_Shared::~PPB_Audio_Shared() {
   // Shut down the socket to escape any hanging |Receive|s.
   if (socket_.get())
     socket_->Shutdown();
   StopThread();
 }
 
 void PPB_Audio_Shared::SetCallback(PPB_Audio_Callback callback,
@@ skipping 21 matching lines @@
 void PPB_Audio_Shared::SetStopPlaybackState() {
   DCHECK(playing_);
   StopThread();
   playing_ = false;
 }
 
 void PPB_Audio_Shared::SetStreamInfo(
     PP_Instance instance,
     base::SharedMemoryHandle shared_memory_handle,
     size_t shared_memory_size,
-    base::SyncSocket::Handle socket_handle) {
+    base::SyncSocket::Handle socket_handle,
+    int sample_frame_count) {
   socket_.reset(new base::CancelableSyncSocket(socket_handle));
   shared_memory_.reset(new base::SharedMemory(shared_memory_handle, false));
   shared_memory_size_ = shared_memory_size;
 
   if (!shared_memory_->Map(
           media::TotalSharedMemorySizeInBytes(shared_memory_size_))) {
     PpapiGlobals::Get()->LogWithSource(instance, PP_LOGLEVEL_WARNING, "",
       "Failed to map shared memory for PPB_Audio_Shared.");
+  } else {
+    audio_bus_ = media::AudioBus::WrapMemory(
+        kChannels, sample_frame_count, shared_memory_.get());
+    // Setup integer audio buffer for user audio data.
+    audio_buffer_size_bytes_ =

[nfullagar, 2012/08/29 18:38:22]

audio_bus and audio_buffer are starting to blur together (for me) when reading
through the code.  Is there a more distinctive name that could better
distinguish between the two?  I like |audio_bus_| as it is, but the other could 
be |audio_client_buffer_| or |client_buffer_| or ..?

[DaleCurtis, 2012/08/29 18:52:23]

Since audio is already in the class name I switched it to |client_buffer_|

+        audio_bus_->frames() * audio_bus_->channels() * kBytesPerSample;
+    audio_buffer_.reset(new uint8_t[audio_buffer_size_bytes_]);
   }
 
   StartThread();
 }
 
 void PPB_Audio_Shared::StartThread() {
   // Don't start the thread unless all our state is set up correctly.
-  if (!playing_ || !callback_ || !socket_.get() || !shared_memory_->memory())
+  if (!playing_ || !callback_ || !socket_.get() || !shared_memory_->memory() ||
+      !audio_bus_.get() || !audio_buffer_.get())
     return;
   // Clear contents of shm buffer before starting audio thread. This will
   // prevent a burst of static if for some reason the audio thread doesn't
   // start up quickly enough.
   memset(shared_memory_->memory(), 0, shared_memory_size_);
+  memset(audio_buffer_.get(), 0, audio_buffer_size_bytes_);
 #if !defined(OS_NACL)
   DCHECK(!audio_thread_.get());
   audio_thread_.reset(new base::DelegateSimpleThread(
       this, "plugin_audio_thread"));
   audio_thread_->Start();
 #else
   // Use NaCl's special API for IRT code that creates threads that call back
   // into user code.
   if (NULL == thread_functions.thread_create ||
       NULL == thread_functions.thread_join)
@@ skipping 31 matching lines @@
 
 // static
 void PPB_Audio_Shared::CallRun(void* self) {
   PPB_Audio_Shared* audio = static_cast<PPB_Audio_Shared*>(self);
   audio->Run();
 }
 #endif
 
 void PPB_Audio_Shared::Run() {
   int pending_data;
-  void* buffer = shared_memory_->memory();
 
   while (sizeof(pending_data) ==
       socket_->Receive(&pending_data, sizeof(pending_data)) &&
       pending_data != media::kPauseMark) {
-    callback_(buffer, shared_memory_size_, user_data_);
+    callback_(audio_buffer_.get(), audio_buffer_size_bytes_, user_data_);
+
+    // Deinterleave the audio data into the shared memory as float.
+    audio_bus_->FromInterleaved(
+        audio_buffer_.get(), audio_bus_->frames(), kBytesPerSample);
 
     // Let the host know we are done.
+    // TODO(dalecurtis): Technically this is not the exact size.  Due to channel
+    // padding for alignment, there may be more data available than this.  We're
+    // relying on AudioSyncReader::Read() to parse this with that in mind.
+    // Rename these methods to Set/GetActualFrameCount().
     media::SetActualDataSizeInBytes(
-        shared_memory_.get(), shared_memory_size_, shared_memory_size_);
+        shared_memory_.get(), shared_memory_size_, audio_bus_->frames() *
+        sizeof(*audio_bus_->channel(0)) * audio_bus_->channels());

[nfullagar, 2012/08/29 18:38:22]

same comment from other proxy re: audio_bus_ buffer size in bytes

[DaleCurtis, 2012/08/29 18:52:23]

Done.

   }
 }
 
 }  // namespace ppapi