Check buffer index in shared memory for input audio.

media/audio/audio_input_device.cc

Index: media/audio/audio_input_device.cc
diff --git a/media/audio/audio_input_device.cc b/media/audio/audio_input_device.cc
index 9f46b55a1b9f365facd573b5f0783cd15f9923af..f9541f16b24f5728de32d2446171e51df2df7095 100644
--- a/media/audio/audio_input_device.cc
+++ b/media/audio/audio_input_device.cc
@@ -39,6 +39,7 @@ class AudioInputDevice::AudioThreadCallback
 
  private:
   int current_segment_id_;
+  uint32 last_buffer_id_;
   ScopedVector<media::AudioBus> audio_buses_;
   CaptureCallback* capture_callback_;
 
@@ -272,6 +273,7 @@ AudioInputDevice::AudioThreadCallback::AudioThreadCallback(
     : AudioDeviceThread::Callback(audio_parameters, memory, memory_length,
                                   total_segments),
       current_segment_id_(0),
+      last_buffer_id_(UINT32_MAX),
       capture_callback_(capture_callback) {
 }
 
@@ -294,6 +296,8 @@ void AudioInputDevice::AudioThreadCallback::MapSharedMemory() {
 }
 
 void AudioInputDevice::AudioThreadCallback::Process(uint32 pending_data) {
+  CHECK_EQ(current_segment_id_, static_cast<int>(pending_data));
+
   // The shared memory represents parameters, size of the data buffer and the
   // actual data buffer containing audio data. Map the memory into this
   // structure and parse out parameters and the data area.
@@ -306,13 +310,22 @@ void AudioInputDevice::AudioThreadCallback::Process(uint32 pending_data) {
             segment_length_ - sizeof(AudioInputBufferParameters));
   double volume = buffer->params.volume;
   bool key_pressed = buffer->params.key_pressed;
+  uint32 hardware_delay_bytes = buffer->params.hardware_delay_bytes;

[tommi (sloooow) - chröme, 2015/08/14 09:56:21]

nit: are these temporaries necessary?

[Henrik Grunell, 2015/08/14 12:38:32]

Good point, removed all of them.

+  uint32 buffer_id = buffer->params.id;
+
+  // Verify correct sequence.
+  if (last_buffer_id_ == UINT32_MAX)

[DaleCurtis, 2015/08/13 22:00:49]

Again, shouldn't be necessary since overflow is defined, UINT32_MAX + 1 == 0

[Henrik Grunell, 2015/08/14 12:38:32]

Done.

+    CHECK_EQ(0u, buffer_id);
+  else
+    CHECK_EQ(last_buffer_id_ + 1, buffer_id);
+  last_buffer_id_ = buffer_id;
 
   // Use pre-allocated audio bus wrapping existing block of shared memory.
   media::AudioBus* audio_bus = audio_buses_[current_segment_id_];
 
   // Deliver captured data to the client in floating point format
   // and update the audio-delay measurement.
-  int audio_delay_milliseconds = pending_data / bytes_per_ms_;
+  int audio_delay_milliseconds = hardware_delay_bytes / bytes_per_ms_;
   capture_callback_->Capture(
       audio_bus, audio_delay_milliseconds, volume, key_pressed);