Collapse AudioRendererMixer and OnMoreDataResampler into AudioTransform.

media/base/audio_pull_fifo.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 "media/base/audio_pull_fifo.h"
 
 #include <algorithm>
 
 #include "base/logging.h"
 
 namespace media {
 
 AudioPullFifo::AudioPullFifo(int channels, int frames, const ReadCB& read_cb)
-    : read_cb_(read_cb) {
+    : read_cb_(read_cb),
+      output_frames_ready_(0) {
   fifo_.reset(new AudioFifo(channels, frames));
   bus_ = AudioBus::Create(channels, frames);
 }
 
 AudioPullFifo::~AudioPullFifo() {
   read_cb_.Reset();
 }
 
 void AudioPullFifo::Consume(AudioBus* destination, int frames_to_consume) {
   DCHECK(destination);
   DCHECK_LE(frames_to_consume, destination->frames());
 
   int write_pos = 0;
   int remaining_frames_to_provide = frames_to_consume;
 
   // Try to fulfill the request using what's available in the FIFO.
   ReadFromFifo(destination, &remaining_frames_to_provide, &write_pos);
 
   // Get the remaining audio frames from the producer using the callback.
   while (remaining_frames_to_provide > 0) {
+    output_frames_ready_ = write_pos;

[scherkus (not reviewing), 2012/11/14 22:43:50]

do we need to update output_frames_ready_ anywhere else? e.g., Clear()?

[DaleCurtis, 2012/11/15 00:30:59]

No, it's not valid to call Clear() during Consume(), the class is not thread
safe.

I'm thinking it might be better to provide this value to the callback directly
instead of this weird side-channel value which is only valid at certain times.
There are only two users (opus and AudioTransform), so it shouldn't be a hard
change.

+
     // Fill up the FIFO by acquiring audio data from the producer.
     read_cb_.Run(bus_.get());
     fifo_->Push(bus_.get());
 
     // Try to fulfill the request using what's available in the FIFO.
     ReadFromFifo(destination, &remaining_frames_to_provide, &write_pos);
   }
 }
 
 void AudioPullFifo::Clear() {
   fifo_->Clear();
 }
 
 void AudioPullFifo::ReadFromFifo(AudioBus* destination,
                                  int* frames_to_provide,
                                  int* write_pos) {
   DCHECK(frames_to_provide);
   DCHECK(write_pos);
   int frames = std::min(fifo_->frames(), *frames_to_provide);
   fifo_->Consume(destination, *write_pos, frames);
   *write_pos += frames;
   *frames_to_provide -= frames;
 }
 
 }  // namespace media