Switch OnMoreData() to use AudioBus.

ppapi/native_client/src/shared/ppapi_proxy/plugin_ppb_audio.cc

Index: ppapi/native_client/src/shared/ppapi_proxy/plugin_ppb_audio.cc
diff --git a/ppapi/native_client/src/shared/ppapi_proxy/plugin_ppb_audio.cc b/ppapi/native_client/src/shared/ppapi_proxy/plugin_ppb_audio.cc
index 18558e6370a576a8848024d31cb1264e2047642f..9eb860ba119290f8fa4aed1b4279c5465c61517f 100644
--- a/ppapi/native_client/src/shared/ppapi_proxy/plugin_ppb_audio.cc
+++ b/ppapi/native_client/src/shared/ppapi_proxy/plugin_ppb_audio.cc
@@ -12,6 +12,7 @@
 #include "native_client/src/include/nacl_scoped_ptr.h"
 #include "native_client/src/include/portability.h"
 #include "native_client/src/shared/ppapi_proxy/plugin_globals.h"
+#include "native_client/src/shared/ppapi_proxy/plugin_ppb_audio_config.h"
 #include "native_client/src/shared/ppapi_proxy/plugin_resource.h"
 #include "native_client/src/shared/ppapi_proxy/utility.h"
 #include "native_client/src/shared/srpc/nacl_srpc.h"
@@ -30,6 +31,10 @@ size_t ceil64k(size_t n) {
   return (n + 0xFFFF) & (~0xFFFF);
 }
 
+// Hard coded values from PepperPlatformAudioOutputImpl.
+// TODO(???): PPAPI shouldn't hard code these values for all clients.
+enum { kChannels = 2, kBytesPerSample = 2 };
+
 }  // namespace
 
 PluginAudio::PluginAudio() :
@@ -42,7 +47,8 @@ PluginAudio::PluginAudio() :
     thread_id_(),
     thread_active_(false),
     user_callback_(NULL),
-    user_data_(NULL) {
+    user_data_(NULL),
+    audio_buffer_size_bytes_(0) {
   DebugPrintf("PluginAudio::PluginAudio\n");
 }
 
@@ -53,10 +59,13 @@ PluginAudio::~PluginAudio() {
     GetInterface()->StopPlayback(resource_);
   // Unmap the shared memory buffer, if present.
   if (shm_buffer_) {
+    audio_bus_.reset();
+    audio_buffer_.reset();
     munmap(shm_buffer_,
            ceil64k(media::TotalSharedMemorySizeInBytes(shm_size_)));
     shm_buffer_ = NULL;
     shm_size_ = 0;
+    audio_buffer_size_bytes_ = 0;
   }
   // Close the handles.
   if (shm_ != -1) {
@@ -87,14 +96,25 @@ void PluginAudio::AudioThread(void* self) {
     if ((sizeof(sync_value) != r) || (-1 == sync_value))
       break;
     // Invoke user callback, get next buffer of audio data.
-    audio->user_callback_(audio->shm_buffer_,
-                          audio->shm_size_,
+    audio->user_callback_(audio->audio_buffer_.get(),
+                          audio->audio_buffer_size_bytes_,
                           audio->user_data_);
+
+    // Deinterleave the audio data into the shared memory as float.
+    audio->audio_bus_->FromInterleaved(
+        audio->audio_buffer_.get(), audio->audio_bus_->frames(),
+        kBytesPerSample);
+
     // Signal audio backend by writing buffer length at end of buffer.
     // (Note: NaCl applications will always write the entire buffer.)
-    media::SetActualDataSizeInBytes(audio->shm_buffer_,
-                                    audio->shm_size_,
-                                    audio->shm_size_);
+    // 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(
+        audio->shm_buffer_, audio->shm_size_, audio->audio_bus_->frames() *
+        sizeof(*(audio->audio_bus_->channel(0))) *
+        audio->audio_bus_->channels());

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

Perhaps cleaner if AudioBus had a member func to return size in bytes of the
buffer (sans padding?)  Or a descriptive temp var?
  media::SetActualDataSizeInBytes(
      audio->shm_buffer_, audio->shm_size_,
      audio->audio_bus_->buffer_size_in_bytes());
...or...
  size_t audio_bus_buffer_size_in_bytes =
      audio->audio_bus_->frames() *
      sizeof(*(audio->audio_bus_->channel(0))) *
      audio->audio_bus_->channels());
  media::SetActualDataSizeInBytes(
      audio->shm_buffer_, audio->shm_size_,
      audio_bus_buffer_size_in_bytes);
...or?

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

Per the TODO this will just be temporary until I rename the
Get/SetActualDataSize methods to Set/GetActualFrameCount() at which point all
that mess will disappear for SetActualFrameCount(audio->shm_buffer_,
audio->shm_size_, audio_bus->frames());

I'll add a local "bytes_per_frame" temp value for now.

   }
 }
 
@@ -112,6 +132,15 @@ void PluginAudio::StreamCreated(NaClSrpcImcDescType socket,
                      shm,
                      0);
   if (MAP_FAILED != shm_buffer_) {
+    PP_Resource ac = GetInterface()->GetCurrentConfig(resource_);
+    int frames = PluginAudioConfig::GetInterface()->GetSampleFrameCount(ac);
+
+    audio_bus_ = media::AudioBus::WrapMemory(kChannels, frames, shm_buffer_);
+    // Setup integer audio buffer for user audio data.
+    audio_buffer_size_bytes_ =
+        audio_bus_->frames() * audio_bus_->channels() * kBytesPerSample;
+    audio_buffer_.reset(new uint8_t[audio_buffer_size_bytes_]);
+
     if (state() == AUDIO_PENDING) {
       StartAudioThread();
     } else {
@@ -126,6 +155,7 @@ bool PluginAudio::StartAudioThread() {
   // clear contents of shm buffer before spinning up audio thread
   DebugPrintf("PluginAudio::StartAudioThread\n");
   memset(shm_buffer_, 0, shm_size_);
+  memset(audio_buffer_.get(), 0, audio_buffer_size_bytes_);
   const struct PP_ThreadFunctions* thread_funcs = GetThreadCreator();
   if (NULL == thread_funcs->thread_create ||
       NULL == thread_funcs->thread_join) {