1 files changed, 308 insertions, 0 deletions
diff --git a/dom/media/AudioStream.h b/dom/media/AudioStream.h
new file mode 100644
index 0000000000..acc38b93db
--- /dev/null
+++ b/dom/media/AudioStream.h
@@ -0,0 +1,308 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#if !defined(AudioStream_h_)
+#define AudioStream_h_
+
+#include "AudioSampleFormat.h"
+#include "nsAutoPtr.h"
+#include "nsCOMPtr.h"
+#include "nsThreadUtils.h"
+#include "mozilla/dom/AudioChannelBinding.h"
+#include "mozilla/Monitor.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/TimeStamp.h"
+#include "mozilla/UniquePtr.h"
+#include "CubebUtils.h"
+#include "soundtouch/SoundTouchFactory.h"
+
+namespace mozilla {
+
+struct CubebDestroyPolicy
+{
+  void operator()(cubeb_stream* aStream) const {
+    cubeb_stream_destroy(aStream);
+  }
+};
+
+class AudioStream;
+class FrameHistory;
+class AudioConfig;
+class AudioConverter;
+
+class AudioClock
+{
+public:
+  AudioClock();
+
+  // Initialize the clock with the current sampling rate.
+  // Need to be called before querying the clock.
+  void Init(uint32_t aRate);
+
+  // Update the number of samples that has been written in the audio backend.
+  // Called on the state machine thread.
+  void UpdateFrameHistory(uint32_t aServiced, uint32_t aUnderrun);
+
+  /**
+   * @param aFrames The playback position in frames of the audio engine.
+   * @return The playback position in frames of the stream,
+   *         adjusted by playback rate changes and underrun frames.
+   */
+  int64_t GetPositionInFrames(int64_t aFrames) const;
+
+  /**
+   * @param frames The playback position in frames of the audio engine.
+   * @return The playback position in microseconds of the stream,
+   *         adjusted by playback rate changes and underrun frames.
+   */
+  int64_t GetPosition(int64_t frames) const;
+
+  // Set the playback rate.
+  // Called on the audio thread.
+  void SetPlaybackRate(double aPlaybackRate);
+  // Get the current playback rate.
+  // Called on the audio thread.
+  double GetPlaybackRate() const;
+  // Set if we are preserving the pitch.
+  // Called on the audio thread.
+  void SetPreservesPitch(bool aPreservesPitch);
+  // Get the current pitch preservation state.
+  // Called on the audio thread.
+  bool GetPreservesPitch() const;
+
+  uint32_t GetInputRate() const { return mInRate; }
+  uint32_t GetOutputRate() const { return mOutRate; }
+
+private:
+  // Output rate in Hz (characteristic of the playback rate)
+  uint32_t mOutRate;
+  // Input rate in Hz (characteristic of the media being played)
+  uint32_t mInRate;
+  // True if the we are timestretching, false if we are resampling.
+  bool mPreservesPitch;
+  // The history of frames sent to the audio engine in each DataCallback.
+  const nsAutoPtr<FrameHistory> mFrameHistory;
+};
+
+/*
+ * A bookkeeping class to track the read/write position of an audio buffer.
+ */
+class AudioBufferCursor {
+public:
+  AudioBufferCursor(AudioDataValue* aPtr, uint32_t aChannels, uint32_t aFrames)
+    : mPtr(aPtr), mChannels(aChannels), mFrames(aFrames) {}
+
+  // Advance the cursor to account for frames that are consumed.
+  uint32_t Advance(uint32_t aFrames) {
+    MOZ_ASSERT(mFrames >= aFrames);
+    mFrames -= aFrames;
+    mPtr += mChannels * aFrames;
+    return aFrames;
+  }
+
+  // The number of frames available for read/write in this buffer.
+  uint32_t Available() const { return mFrames; }
+
+  // Return a pointer where read/write should begin.
+  AudioDataValue* Ptr() const { return mPtr; }
+
+protected:
+  AudioDataValue* mPtr;
+  const uint32_t mChannels;
+  uint32_t mFrames;
+};
+
+/*
+ * A helper class to encapsulate pointer arithmetic and provide means to modify
+ * the underlying audio buffer.
+ */
+class AudioBufferWriter : private AudioBufferCursor {
+public:
+  AudioBufferWriter(AudioDataValue* aPtr, uint32_t aChannels, uint32_t aFrames)
+    : AudioBufferCursor(aPtr, aChannels, aFrames) {}
+
+  uint32_t WriteZeros(uint32_t aFrames) {
+    memset(mPtr, 0, sizeof(AudioDataValue) * mChannels * aFrames);
+    return Advance(aFrames);
+  }
+
+  uint32_t Write(const AudioDataValue* aPtr, uint32_t aFrames) {
+    memcpy(mPtr, aPtr, sizeof(AudioDataValue) * mChannels * aFrames);
+    return Advance(aFrames);
+  }
+
+  // Provide a write fuction to update the audio buffer with the following
+  // signature: uint32_t(const AudioDataValue* aPtr, uint32_t aFrames)
+  // aPtr: Pointer to the audio buffer.
+  // aFrames: The number of frames available in the buffer.
+  // return: The number of frames actually written by the function.
+  template <typename Function>
+  uint32_t Write(const Function& aFunction, uint32_t aFrames) {
+    return Advance(aFunction(mPtr, aFrames));
+  }
+
+  using AudioBufferCursor::Available;
+};
+
+// Access to a single instance of this class must be synchronized by
+// callers, or made from a single thread.  One exception is that access to
+// GetPosition, GetPositionInFrames, SetVolume, and Get{Rate,Channels},
+// SetMicrophoneActive is thread-safe without external synchronization.
+class AudioStream final
+{
+  virtual ~AudioStream();
+
+public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(AudioStream)
+
+  class Chunk {
+  public:
+    // Return a pointer to the audio data.
+    virtual const AudioDataValue* Data() const = 0;
+    // Return the number of frames in this chunk.
+    virtual uint32_t Frames() const = 0;
+    // Return the number of audio channels.
+    virtual uint32_t Channels() const = 0;
+    // Return the sample rate of this chunk.
+    virtual uint32_t Rate() const = 0;
+    // Return a writable pointer for downmixing.
+    virtual AudioDataValue* GetWritable() const = 0;
+    virtual ~Chunk() {}
+  };
+
+  class DataSource {
+  public:
+    // Return a chunk which contains at most aFrames frames or zero if no
+    // frames in the source at all.
+    virtual UniquePtr<Chunk> PopFrames(uint32_t aFrames) = 0;
+    // Return true if no more data will be added to the source.
+    virtual bool Ended() const = 0;
+    // Notify that all data is drained by the AudioStream.
+    virtual void Drained() = 0;
+  protected:
+    virtual ~DataSource() {}
+  };
+
+  explicit AudioStream(DataSource& aSource);
+
+  // Initialize the audio stream. aNumChannels is the number of audio
+  // channels (1 for mono, 2 for stereo, etc) and aRate is the sample rate
+  // (22050Hz, 44100Hz, etc).
+  nsresult Init(uint32_t aNumChannels, uint32_t aRate,
+                const dom::AudioChannel aAudioStreamChannel);
+
+  // Closes the stream. All future use of the stream is an error.
+  void Shutdown();
+
+  void Reset();
+
+  // Set the current volume of the audio playback. This is a value from
+  // 0 (meaning muted) to 1 (meaning full volume).  Thread-safe.
+  void SetVolume(double aVolume);
+
+  // Start the stream.
+  void Start();
+
+  // Pause audio playback.
+  void Pause();
+
+  // Resume audio playback.
+  void Resume();
+
+  // Return the position in microseconds of the audio frame being played by
+  // the audio hardware, compensated for playback rate change. Thread-safe.
+  int64_t GetPosition();
+
+  // Return the position, measured in audio frames played since the stream
+  // was opened, of the audio hardware.  Thread-safe.
+  int64_t GetPositionInFrames();
+
+  static uint32_t GetPreferredRate()
+  {
+    return CubebUtils::PreferredSampleRate();
+  }
+
+  uint32_t GetOutChannels() { return mOutChannels; }
+
+  // Set playback rate as a multiple of the intrinsic playback rate. This is to
+  // be called only with aPlaybackRate > 0.0.
+  nsresult SetPlaybackRate(double aPlaybackRate);
+  // Switch between resampling (if false) and time stretching (if true, default).
+  nsresult SetPreservesPitch(bool aPreservesPitch);
+
+  size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const;
+
+protected:
+  friend class AudioClock;
+
+  // Return the position, measured in audio frames played since the stream was
+  // opened, of the audio hardware, not adjusted for the changes of playback
+  // rate or underrun frames.
+  // Caller must own the monitor.
+  int64_t GetPositionInFramesUnlocked();
+
+private:
+  nsresult OpenCubeb(cubeb* aContext, cubeb_stream_params& aParams,
+                     TimeStamp aStartTime, bool aIsFirst);
+
+  static long DataCallback_S(cubeb_stream*, void* aThis,
+                             const void* /* aInputBuffer */, void* aOutputBuffer,
+                             long aFrames)
+  {
+    return static_cast<AudioStream*>(aThis)->DataCallback(aOutputBuffer, aFrames);
+  }
+
+  static void StateCallback_S(cubeb_stream*, void* aThis, cubeb_state aState)
+  {
+    static_cast<AudioStream*>(aThis)->StateCallback(aState);
+  }
+
+
+  long DataCallback(void* aBuffer, long aFrames);
+  void StateCallback(cubeb_state aState);
+
+  nsresult EnsureTimeStretcherInitializedUnlocked();
+
+  // Return true if audio frames are valid (correct sampling rate and valid
+  // channel count) otherwise false.
+  bool IsValidAudioFormat(Chunk* aChunk);
+
+  void GetUnprocessed(AudioBufferWriter& aWriter);
+  void GetTimeStretched(AudioBufferWriter& aWriter);
+
+  template <typename Function, typename... Args>
+  int InvokeCubeb(Function aFunction, Args&&... aArgs);
+
+  // The monitor is held to protect all access to member variables.
+  Monitor mMonitor;
+
+  uint32_t mChannels;
+  uint32_t mOutChannels;
+  AudioClock mAudioClock;
+  soundtouch::SoundTouch* mTimeStretcher;
+
+  // Output file for dumping audio
+  FILE* mDumpFile;
+
+  // Owning reference to a cubeb_stream.
+  UniquePtr<cubeb_stream, CubebDestroyPolicy> mCubebStream;
+
+  enum StreamState {
+    INITIALIZED, // Initialized, playback has not begun.
+    STARTED,     // cubeb started.
+    STOPPED,     // Stopped by a call to Pause().
+    DRAINED,     // StateCallback has indicated that the drain is complete.
+    ERRORED,     // Stream disabled due to an internal error.
+    SHUTDOWN     // Shutdown has been called
+  };
+
+  StreamState mState;
+
+  DataSource& mDataSource;
+};
+
+} // namespace mozilla
+
+#endif