Add the ability to read/write to WAV files in FakeAudioDevice

webrtc/test/fake_audio_device.h

Index: webrtc/test/fake_audio_device.h
diff --git a/webrtc/test/fake_audio_device.h b/webrtc/test/fake_audio_device.h
index 4daeab43650066c258d0bb172a12d14f36fe64c3..386f8390f98fc0eee7f81d1faccf9f4eb433bed8 100644
--- a/webrtc/test/fake_audio_device.h
+++ b/webrtc/test/fake_audio_device.h
@@ -14,7 +14,10 @@
 #include <string>
 #include <vector>
 
+#include "webrtc/base/array_view.h"
+#include "webrtc/base/buffer.h"
 #include "webrtc/base/criticalsection.h"
+#include "webrtc/base/event.h"
 #include "webrtc/base/platform_thread.h"
 #include "webrtc/modules/audio_device/include/fake_audio_device.h"
 #include "webrtc/typedefs.h"
@@ -29,18 +32,68 @@ namespace test {
 // capturer and a renderer. It will use 10ms audio frames.
 class FakeAudioDevice : public FakeAudioDeviceModule {
  public:
+  // Returns the number of samples that Capturers and Renderers with this
+  // sampling frequency will work with every time Capture or Render is called.
+  static size_t SamplesPerFrame(int sampling_frequency_in_hz);

[kwiberg-webrtc, 2017/03/13 14:22:28]

Can this function be in the anonymous namespace in the .cc file?

[oprypin_webrtc, 2017/03/13 15:11:36]

I intend to implement more specialized Capturers/Renderers outside of this .cc
file, and they need to use it.

[kwiberg-webrtc, 2017/03/14 10:02:03]

Acknowledged.

+
+  class Capturer {
+   public:
+    virtual ~Capturer() {}
+    // Returns the sampling frequency in Hz of the audio data that this
+    // capturer produces.
+    virtual int SamplingFrequency() const = 0;
+    // Captures some audio data and puts it into the passed buffer. The final
+    // size of the buffer should not exceed its initial size, which is equal to
+    // SamplesPerFrame. Returns true if the capturer can keep producing data,

[kwiberg-webrtc, 2017/03/13 14:22:29]

Hmmm... why the behavior described in the second sentence? Wouldn't it be enough
to say just "Replaces the contents of |buffer| with at most 10 ms of captured
audio data.", or something like that?

[oprypin_webrtc, 2017/03/13 15:11:36]

It's just not obvious what 10ms of data is, I thought this would make it more
convenient. Made it simpler.

[kwiberg-webrtc, 2017/03/14 10:02:03]

Thanks, looks good now.

+    // or false when the capture finishes.
+    virtual bool Capture(rtc::BufferT<int16_t>* buffer) = 0;
+  };
+
+  class Renderer {
+   public:
+    virtual ~Renderer() {}
+    // Returns the sampling frequency in Hz of the audio data that this
+    // renderer receives.
+    virtual int SamplingFrequency() const = 0;
+    // Renders the passed audio data and returns true if the renderer wants
+    // to keep receiving data, or false otherwise.
+    virtual bool Render(rtc::ArrayView<const int16_t> data) = 0;
+  };
+
   // Creates a new FakeAudioDevice. When capturing or playing, 10 ms audio
-  // frames will be processed every 100ms / |speed|.
-  // |sampling_frequency_in_hz| can be 8, 16, 32, 44.1 or 48kHz.
-  // When recording is started, it will generates a signal where every second
+  // frames will be processed every 10ms / |speed|.
+  // |capturer| is an object that produces audio data. Can be nullptr if this
+  // device is never used for recording.
+  // |renderer| is an object that receives audio data that would have been
+  // played out. Can be nullptr if this device is never used for playing.
+  // Use one of the Create... functions to get these instances.
+  FakeAudioDevice(std::unique_ptr<Capturer> capturer,
+                  std::unique_ptr<Renderer> renderer,
+                  float speed = 1);
+  ~FakeAudioDevice() override;
+
+  // Returns a Capturer instance that generates a signal where every second
   // frame is zero and every second frame is evenly distributed random noise
   // with max amplitude |max_amplitude|.
-  FakeAudioDevice(float speed,
-                  int sampling_frequency_in_hz,
-                  int16_t max_amplitude);
-  ~FakeAudioDevice() override;
+  static std::unique_ptr<Capturer> CreatePulsedNoiseCapturer(
+      int16_t max_amplitude, int sampling_frequency_in_hz);
+
+  // Returns a Capturer instance that gets its data from a file.
+  static std::unique_ptr<Capturer> CreateWavFileReader(
+      std::string filename, int sampling_frequency_in_hz);
+
+  // Returns a Capturer instance that gets its data from a file.
+  // Automatically detects sample rate.
+  static std::unique_ptr<Capturer> CreateWavFileReader(std::string filename);
+
+  // Returns a Renderer instance that writes its data to a file.
+  static std::unique_ptr<Renderer> CreateWavFileWriter(
+      std::string filename, int sampling_frequency_in_hz);
+
+  // Returns a Renderer instance that does nothing with the audio data.
+  static std::unique_ptr<Renderer> CreateDiscardRenderer(
+      int sampling_frequency_in_hz);
 
- private:
   int32_t Init() override;
   int32_t RegisterAudioCallback(AudioTransport* callback) override;
 
@@ -52,22 +105,30 @@ class FakeAudioDevice : public FakeAudioDeviceModule {
   bool Playing() const override;
   bool Recording() const override;
 
+  // Blocks until the Renderer refuses to receive data.
+  // Returns false if |timeout_ms| passes before that happens.
+  bool WaitForPlayoutEnd(int timeout_ms = rtc::Event::kForever);
+  // Blocks until the Recorder stops producing data.
+  // Returns false if |timeout_ms| passes before that happens.
+  bool WaitForRecordingEnd(int timeout_ms = rtc::Event::kForever);
+
+ private:
   static bool Run(void* obj);
   void ProcessAudio();
 
-  const int sampling_frequency_in_hz_;
-  const size_t num_samples_per_frame_;
+  const std::unique_ptr<Capturer> capturer_ GUARDED_BY(lock_);
+  const std::unique_ptr<Renderer> renderer_ GUARDED_BY(lock_);
   const float speed_;
 
   rtc::CriticalSection lock_;
   AudioTransport* audio_callback_ GUARDED_BY(lock_);
   bool rendering_ GUARDED_BY(lock_);
   bool capturing_ GUARDED_BY(lock_);
-
-  class PulsedNoiseCapturer;
-  const std::unique_ptr<PulsedNoiseCapturer> capturer_ GUARDED_BY(lock_);
+  rtc::Event done_rendering_;
+  rtc::Event done_capturing_;
 
   std::vector<int16_t> playout_buffer_ GUARDED_BY(lock_);
+  rtc::BufferT<int16_t> recording_buffer_ GUARDED_BY(lock_);
 
   std::unique_ptr<EventTimerWrapper> tick_;
   rtc::PlatformThread thread_;