Index: media/base/audio_fifo.cc |
=================================================================== |
--- media/base/audio_fifo.cc (revision 157152) |
+++ media/base/audio_fifo.cc (working copy) |
@@ -6,6 +6,9 @@ |
#include "base/logging.h" |
+using base::subtle::Atomic32; |
+using base::subtle::NoBarrier_Store; |
+ |
namespace media { |
// Given current position in the FIFO, the maximum number of elements in the |
@@ -40,19 +43,26 @@ |
AudioFifo::AudioFifo(int channels, int frames) |
: audio_bus_(AudioBus::Create(channels, frames)), |
max_frames_(frames), |
- frames_(0), |
+ frames_pushed_(0), |
+ frames_consumed_(0), |
read_pos_(0), |
write_pos_(0) {} |
AudioFifo::~AudioFifo() {} |
+int AudioFifo::frames() const { |
+ int delta = frames_pushed_ - frames_consumed_; |
+ base::subtle::MemoryBarrier(); |
+ return delta; |
+} |
+ |
void AudioFifo::Push(const AudioBus* source) { |
DCHECK(source); |
DCHECK_EQ(source->channels(), audio_bus_->channels()); |
// Ensure that there is space for the new data in the FIFO. |
const int source_size = source->frames(); |
- CHECK_LE(source_size + frames_, max_frames_); |
+ CHECK_LE(source_size + frames(), max_frames_); |
// Figure out if wrapping is needed and if so what segment sizes we need |
// when adding the new audio bus content to the FIFO. |
@@ -73,8 +83,13 @@ |
} |
} |
- frames_ += source_size; |
- DCHECK_LE(frames_, max_frames()); |
+ // Ensure the data is *really* written before updating |frames_pushed_|. |
+ base::subtle::MemoryBarrier(); |
+ |
+ Atomic32 new_frames_pushed = frames_pushed_ + source_size; |
+ NoBarrier_Store(&frames_pushed_, new_frames_pushed); |
+ |
+ DCHECK_LE(frames(), max_frames()); |
write_pos_ = UpdatePos(write_pos_, source_size, max_frames()); |
} |
@@ -85,7 +100,7 @@ |
DCHECK_EQ(destination->channels(), audio_bus_->channels()); |
// It is not possible to ask for more data than what is available in the FIFO. |
- CHECK_LE(frames_to_consume, frames_); |
+ CHECK_LE(frames_to_consume, frames()); |
// A copy from the FIFO to |destination| will only be performed if the |
// allocated memory in |destination| is sufficient. |
@@ -113,12 +128,15 @@ |
} |
} |
jbauman
2012/09/18 00:26:57
Could you make sure to put another memory barrier
|
- frames_ -= frames_to_consume; |
+ Atomic32 new_frames_consumed = frames_consumed_ + frames_to_consume; |
+ NoBarrier_Store(&frames_consumed_, new_frames_consumed); |
+ |
read_pos_ = UpdatePos(read_pos_, frames_to_consume, max_frames()); |
} |
void AudioFifo::Clear() { |
- frames_ = 0; |
+ frames_pushed_ = 0; |
+ frames_consumed_ = 0; |
read_pos_ = 0; |
write_pos_ = 0; |
} |