Remove "high"-latency audio code path

content/browser/renderer_host/media/audio_renderer_host.cc

 // Copyright (c) 2011 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 "content/browser/renderer_host/media/audio_renderer_host.h"
 
 #include "base/bind.h"
 #include "base/metrics/histogram.h"
 #include "base/process.h"
 #include "base/shared_memory.h"
 #include "content/browser/renderer_host/media/audio_common.h"
 #include "content/browser/renderer_host/media/audio_sync_reader.h"
 #include "content/browser/renderer_host/media/media_observer.h"
 #include "content/browser/resource_context.h"
 #include "content/common/media/audio_messages.h"
 #include "media/audio/audio_util.h"
 #include "ipc/ipc_logging.h"
 
 using content::BrowserMessageFilter;
 using content::BrowserThread;
 
 AudioRendererHost::AudioEntry::AudioEntry()
     : stream_id(0),
-      pending_buffer_request(false),
       pending_close(false) {
 }
 
 AudioRendererHost::AudioEntry::~AudioEntry() {}
 
 ///////////////////////////////////////////////////////////////////////////////
 // AudioRendererHost implementations.
 AudioRendererHost::AudioRendererHost(
     const content::ResourceContext* resource_context)
     : resource_context_(resource_context),
@@ skipping 49 matching lines @@
 
 void AudioRendererHost::OnError(media::AudioOutputController* controller,
                                 int error_code) {
   BrowserThread::PostTask(
       BrowserThread::IO,
       FROM_HERE,
       base::Bind(&AudioRendererHost::DoHandleError,
                  this, make_scoped_refptr(controller), error_code));
 }
 
-void AudioRendererHost::OnMoreData(media::AudioOutputController* controller,
-                                   AudioBuffersState buffers_state) {
-  BrowserThread::PostTask(
-      BrowserThread::IO,
-      FROM_HERE,
-      base::Bind(&AudioRendererHost::DoRequestMoreData,
-                 this, make_scoped_refptr(controller),
-                 buffers_state));
-}
-
 void AudioRendererHost::DoCompleteCreation(
     media::AudioOutputController* controller) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
 
   AudioEntry* entry = LookupByController(controller);
   if (!entry)
     return;
 
   if (!peer_handle()) {
     NOTREACHED() << "Renderer process handle is invalid.";
     DeleteEntryOnError(entry);
     return;
   }
 
   // Once the audio stream is created then complete the creation process by
   // mapping shared memory and sharing with the renderer process.
   base::SharedMemoryHandle foreign_memory_handle;
   if (!entry->shared_memory.ShareToProcess(peer_handle(),
                                            &foreign_memory_handle)) {
     // If we failed to map and share the shared memory then close the audio
     // stream and send an error message.
     DeleteEntryOnError(entry);
     return;
   }
 
-  if (entry->controller->LowLatencyMode()) {
-    AudioSyncReader* reader =
-        static_cast<AudioSyncReader*>(entry->reader.get());
+  AudioSyncReader* reader =
+      static_cast<AudioSyncReader*>(entry->reader.get());

[scherkus (not reviewing), 2012/01/28 02:12:52]

do you happen to know why we can't have AudioSyncReader inside the .h for
AudioEntry?

[vrk (LEFT CHROMIUM), 2012/01/31 23:53:08]

Doesn't seem like there's a reason not to have it there! Mind if I do the move
in a separate CL?

 
 #if defined(OS_WIN)
-    base::SyncSocket::Handle foreign_socket_handle;
+  base::SyncSocket::Handle foreign_socket_handle;
 #else
-    base::FileDescriptor foreign_socket_handle;
+  base::FileDescriptor foreign_socket_handle;
 #endif
 
-    // If we failed to prepare the sync socket for the renderer then we fail
-    // the construction of audio stream.
-    if (!reader->PrepareForeignSocketHandle(peer_handle(),
-                                            &foreign_socket_handle)) {
-      DeleteEntryOnError(entry);
-      return;
-    }
-
-    Send(new AudioMsg_NotifyLowLatencyStreamCreated(
-        entry->stream_id,
-        foreign_memory_handle,
-        foreign_socket_handle,
-        media::PacketSizeSizeInBytes(entry->shared_memory.created_size())));
+  // If we failed to prepare the sync socket for the renderer then we fail
+  // the construction of audio stream.
+  if (!reader->PrepareForeignSocketHandle(peer_handle(),
+                                          &foreign_socket_handle)) {
+    DeleteEntryOnError(entry);
     return;
   }
 
-  // The normal audio stream has created, send a message to the renderer
-  // process.
-  Send(new AudioMsg_NotifyStreamCreated(
-      entry->stream_id, foreign_memory_handle,
-      entry->shared_memory.created_size()));
+  Send(new AudioMsg_NotifyLowLatencyStreamCreated(

[henrika (OOO until Aug 14), 2012/01/29 20:54:00]

Proposal: remove "LowLatency"

[scherkus (not reviewing), 2012/01/30 19:02:00]

Yeah I agree w/ henrika here. I didn't suggest it earlier as I thought we still
needed to distinguish between WASAPI-like low latency output and default output
methods.

We really need to agree on some terminology :P

[vrk (LEFT CHROMIUM), 2012/01/31 23:53:08]

Done.

[vrk (LEFT CHROMIUM), 2012/01/31 23:53:08]

Done - Except for the audio input-related LowLatency stuff, as I mentioned in
another comment.

+      entry->stream_id,
+      foreign_memory_handle,
+      foreign_socket_handle,
+      media::PacketSizeSizeInBytes(entry->shared_memory.created_size())));
 }
 
 void AudioRendererHost::DoSendPlayingMessage(
     media::AudioOutputController* controller) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
 
   AudioEntry* entry = LookupByController(controller);
   if (!entry)
     return;
 
   Send(new AudioMsg_NotifyStreamStateChanged(
     entry->stream_id, kAudioStreamPlaying));
 }
 
 void AudioRendererHost::DoSendPausedMessage(
     media::AudioOutputController* controller) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
 
   AudioEntry* entry = LookupByController(controller);
   if (!entry)
     return;
 
   Send(new AudioMsg_NotifyStreamStateChanged(
       entry->stream_id, kAudioStreamPaused));
 }
 
-void AudioRendererHost::DoRequestMoreData(
-    media::AudioOutputController* controller,
-    AudioBuffersState buffers_state) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
-
-  // If we already have a pending request then return.
-  AudioEntry* entry = LookupByController(controller);
-  if (!entry || entry->pending_buffer_request)
-    return;
-
-  DCHECK(!entry->controller->LowLatencyMode());
-  entry->pending_buffer_request = true;
-  Send(new AudioMsg_RequestPacket(
-      entry->stream_id, buffers_state));
-}
-
 void AudioRendererHost::DoHandleError(media::AudioOutputController* controller,
                                       int error_code) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
 
   AudioEntry* entry = LookupByController(controller);
   if (!entry)
     return;
 
   DeleteEntryOnError(entry);
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 // IPC Messages handler
 bool AudioRendererHost::OnMessageReceived(const IPC::Message& message,
                                           bool* message_was_ok) {
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP_EX(AudioRendererHost, message, *message_was_ok)
     IPC_MESSAGE_HANDLER(AudioHostMsg_CreateStream, OnCreateStream)
     IPC_MESSAGE_HANDLER(AudioHostMsg_PlayStream, OnPlayStream)
     IPC_MESSAGE_HANDLER(AudioHostMsg_PauseStream, OnPauseStream)
     IPC_MESSAGE_HANDLER(AudioHostMsg_FlushStream, OnFlushStream)
     IPC_MESSAGE_HANDLER(AudioHostMsg_CloseStream, OnCloseStream)
-    IPC_MESSAGE_HANDLER(AudioHostMsg_NotifyPacketReady, OnNotifyPacketReady)
-    IPC_MESSAGE_HANDLER(AudioHostMsg_GetVolume, OnGetVolume)

[henrika (OOO until Aug 14), 2012/01/29 20:54:00]

Not sure why GetVolume() has been removed and how that is related to this CL.

[vrk (LEFT CHROMIUM), 2012/01/31 23:53:08]

Answered in previous comment!

     IPC_MESSAGE_HANDLER(AudioHostMsg_SetVolume, OnSetVolume)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP_EX()
 
   return handled;
 }
 
 void AudioRendererHost::OnCreateStream(
-    int stream_id, const AudioParameters& params, bool low_latency) {
+    int stream_id, const AudioParameters& params) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   DCHECK(LookupById(stream_id) == NULL);
 
   AudioParameters audio_params(params);
 
   // Select the hardware packet size if not specified.
   if (!audio_params.samples_per_packet) {
     audio_params.samples_per_packet = SelectSamplesPerPacket(audio_params);
   }
   uint32 packet_size = audio_params.GetPacketSize();
 
   scoped_ptr<AudioEntry> entry(new AudioEntry());
   // Create the shared memory and share with the renderer process.

[henrika (OOO until Aug 14), 2012/01/29 20:54:00]

New line above comment.

[vrk (LEFT CHROMIUM), 2012/01/31 23:53:08]

Done.

-  uint32 shared_memory_size = packet_size;
-  if (low_latency) {
-    shared_memory_size =
-        media::TotalSharedMemorySizeInBytes(shared_memory_size);
-  }
+  uint32 shared_memory_size =
+      media::TotalSharedMemorySizeInBytes(packet_size);
   if (!entry->shared_memory.CreateAndMapAnonymous(shared_memory_size)) {
     // If creation of shared memory failed then send an error message.
     SendErrorMessage(stream_id);
     return;
   }
 
-  if (low_latency) {
-    // If this is the low latency mode, we need to construct a SyncReader first.
-    scoped_ptr<AudioSyncReader> reader(
-        new AudioSyncReader(&entry->shared_memory));
+  // Create sync reader and try to initialize it.
+  scoped_ptr<AudioSyncReader> reader(
+      new AudioSyncReader(&entry->shared_memory));
 
-    // Then try to initialize the sync reader.
-    if (!reader->Init()) {
-      SendErrorMessage(stream_id);
-      return;
-    }
+  if (!reader->Init()) {
+    SendErrorMessage(stream_id);
+    return;
+  }
 
-    // If we have successfully created the SyncReader then assign it to the
-    // entry and construct an AudioOutputController.
-    entry->reader.reset(reader.release());
-    entry->controller =
-        media::AudioOutputController::CreateLowLatency(
-            resource_context_->audio_manager(), this, audio_params,
-            entry->reader.get());
-  } else {
-    // The choice of buffer capacity is based on experiment.
-    entry->controller =
-        media::AudioOutputController::Create(
-            resource_context_->audio_manager(), this, audio_params,
-            3 * packet_size);
-  }
+  // If we have successfully created the SyncReader then assign it to the
+  // entry and construct an AudioOutputController.
+  entry->reader.reset(reader.release());
+  entry->controller =

[henrika (OOO until Aug 14), 2012/01/29 20:54:00]

Is it possible to improve indentation here? Feels like line 231 could be moved
up to 230 perhaps.

[vrk (LEFT CHROMIUM), 2012/01/31 23:53:08]

Done.

+      media::AudioOutputController::Create(
+          resource_context_->audio_manager(), this, audio_params,
+          entry->reader.get());
 
   if (!entry->controller) {
     SendErrorMessage(stream_id);
     return;
   }
 
   // If we have created the controller successfully create a entry and add it

[henrika (OOO until Aug 14), 2012/01/29 20:54:00]

"an entry"

[vrk (LEFT CHROMIUM), 2012/01/31 23:53:08]

Done.

   // to the map.
   entry->stream_id = stream_id;
   audio_entries_.insert(std::make_pair(stream_id, entry.release()));
   media_observer()->OnSetAudioStreamStatus(this, stream_id, "created");
 }
 
 void AudioRendererHost::OnPlayStream(int stream_id) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
 
   AudioEntry* entry = LookupById(stream_id);
@@ skipping 52 matching lines @@
     return;
   }
 
   // Make sure the volume is valid.
   if (volume < 0 || volume > 1.0)
     return;
   entry->controller->SetVolume(volume);
   media_observer()->OnSetAudioStreamVolume(this, stream_id, volume);
 }
 
-void AudioRendererHost::OnGetVolume(int stream_id) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
-  NOTREACHED() << "This message shouldn't be received";
-}
-
-void AudioRendererHost::OnNotifyPacketReady(int stream_id, uint32 packet_size) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
-
-  AudioEntry* entry = LookupById(stream_id);
-  if (!entry) {
-    SendErrorMessage(stream_id);
-    return;
-  }
-
-  DCHECK(!entry->controller->LowLatencyMode());
-  CHECK(packet_size <= entry->shared_memory.created_size());
-
-  if (!entry->pending_buffer_request) {
-    NOTREACHED() << "Buffer received but no such pending request";
-  }
-  entry->pending_buffer_request = false;
-
-  // Enqueue the data to media::AudioOutputController.
-  entry->controller->EnqueueData(
-      reinterpret_cast<uint8*>(entry->shared_memory.memory()),
-      packet_size);
-}
-
 void AudioRendererHost::SendErrorMessage(int32 stream_id) {
   Send(new AudioMsg_NotifyStreamStateChanged(stream_id, kAudioStreamError));
 }
 
 void AudioRendererHost::DeleteEntries() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
 
   for (AudioEntryMap::iterator i = audio_entries_.begin();
        i != audio_entries_.end(); ++i) {
     CloseAndDeleteStream(i->second);
@@ skipping 64 matching lines @@
   }
   return NULL;
 }
 
 MediaObserver* AudioRendererHost::media_observer() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   if (!media_observer_)
     media_observer_ = resource_context_->media_observer();
   return media_observer_;
 }