dom/media/CubebInputStream.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef DOM_MEDIA_CUBEBINPUTSTREAM_H_
   8 #define DOM_MEDIA_CUBEBINPUTSTREAM_H_
   9
  10 #include "CubebUtils.h"
  11 #include "mozilla/Maybe.h"
  12 #include "mozilla/RefPtr.h"
  13 #include "mozilla/UniquePtr.h"
  14 #include "nsISupportsImpl.h"
  15
  16 namespace mozilla {
  17
  18 // A light-weight wrapper to operate the C style Cubeb APIs for an input-only
  19 // audio stream in a C++-friendly way.
  20 // Limitation: Do not call these APIs in an audio callback thread. Otherwise we
  21 // may get a deadlock.
  22 class CubebInputStream final {
  23  public:
  24   ~CubebInputStream() = default;
  25
  26   class Listener {
  27    public:
  28     NS_INLINE_DECL_PURE_VIRTUAL_REFCOUNTING;
  29
  30     // This will be fired on audio callback thread.
  31     virtual long DataCallback(const void* aBuffer, long aFrames) = 0;
  32     // This can be fired on any thread.
  33     virtual void StateCallback(cubeb_state aState) = 0;
  34     // This can be fired on any thread.
  35     virtual void DeviceChangedCallback() = 0;
  36
  37    protected:
  38     Listener() = default;
  39     virtual ~Listener() = default;
  40   };
  41
  42   // Return a non-null pointer if the stream has been initialized
  43   // successfully. Otherwise return a null pointer.
  44   static UniquePtr<CubebInputStream> Create(cubeb_devid aDeviceId,
  45                                             uint32_t aChannels, uint32_t aRate,
  46                                             bool aIsVoice, Listener* aListener);
  47
  48   // Start producing audio data.
  49   int Start();
  50
  51   // Stop producing audio data.
  52   int Stop();
  53
  54   // Gets the approximate stream latency in frames.
  55   int Latency(uint32_t* aLatencyFrames);
  56
  57  private:
  58   struct CubebDestroyPolicy {
  59     void operator()(cubeb_stream* aStream) const;
  60   };
  61   CubebInputStream(already_AddRefed<Listener>&& aListener,
  62                    UniquePtr<cubeb_stream, CubebDestroyPolicy>&& aStream);
  63
  64   void Init();
  65
  66   template <typename Function, typename... Args>
  67   int InvokeCubeb(Function aFunction, Args&&... aArgs);
  68
  69   // Static wrapper function cubeb callbacks.
  70   static long DataCallback_s(cubeb_stream* aStream, void* aUser,
  71                              const void* aInputBuffer, void* aOutputBuffer,
  72                              long aFrames);
  73   static void StateCallback_s(cubeb_stream* aStream, void* aUser,
  74                               cubeb_state aState);
  75   static void DeviceChangedCallback_s(void* aUser);
  76
  77   // mListener must outlive the life time of the mStream.
  78   const RefPtr<Listener> mListener;
  79   // So must mCubeb (mStream has a bare pointer to cubeb).
  80   const RefPtr<CubebUtils::CubebHandle> mCubeb;
  81   const UniquePtr<cubeb_stream, CubebDestroyPolicy> mStream;
  82 };
  83
  84 }  // namespace mozilla
  85
  86 #endif  // DOM_MEDIA_CUBEBINPUTSTREAM_H_