The Tor Browser: content/media/webrtc/MediaEngine.h@44a2da4a2ab2

Replace accessor implementation with direct member state manipulation, by
request https://trac.torproject.org/projects/tor/ticket/9701#comment:32

     1 /* This Source Code Form is subject to the terms of the Mozilla Public

     2  * License, v. 2.0. If a copy of the MPL was not distributed with this file,

     3  * You can obtain one at http://mozilla.org/MPL/2.0/. */

     5 #ifndef MEDIAENGINE_H_

     6 #define MEDIAENGINE_H_

     8 #include "mozilla/RefPtr.h"

     9 #include "nsIDOMFile.h"

    10 #include "DOMMediaStream.h"

    11 #include "MediaStreamGraph.h"

    13 namespace mozilla {

    15 class VideoTrackConstraintsN;

    16 class AudioTrackConstraintsN;

    18 /**

    19  * Abstract interface for managing audio and video devices. Each platform

    20  * must implement a concrete class that will map these classes and methods

    21  * to the appropriate backend. For example, on Desktop platforms, these will

    22  * correspond to equivalent webrtc (GIPS) calls, and on B2G they will map to

    23  * a Gonk interface.

    24  */

    25 class MediaEngineVideoSource;

    26 class MediaEngineAudioSource;

    27 struct MediaEnginePrefs;

    29 enum MediaEngineState {

    30   kAllocated,

    31   kStarted,

    32   kStopped,

    33   kReleased

    34 };

    36 // We only support 1 audio and 1 video track for now.

    37 enum {

    38   kVideoTrack = 1,

    39   kAudioTrack = 2

    40 };

    42 class MediaEngine

    43 {

    44 public:

    45   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(MediaEngine)

    47   static const int DEFAULT_VIDEO_FPS = 30;

    48   static const int DEFAULT_VIDEO_MIN_FPS = 10;

    49   static const int DEFAULT_43_VIDEO_WIDTH = 640;

    50   static const int DEFAULT_43_VIDEO_HEIGHT = 480;

    51   static const int DEFAULT_169_VIDEO_WIDTH = 1280;

    52   static const int DEFAULT_169_VIDEO_HEIGHT = 720;

    53   static const int DEFAULT_AUDIO_TIMER_MS = 10;

    55   /* Populate an array of video sources in the nsTArray. Also include devices

    56    * that are currently unavailable. */

    57   virtual void EnumerateVideoDevices(nsTArray<nsRefPtr<MediaEngineVideoSource> >*) = 0;

    59   /* Populate an array of audio sources in the nsTArray. Also include devices

    60    * that are currently unavailable. */

    61   virtual void EnumerateAudioDevices(nsTArray<nsRefPtr<MediaEngineAudioSource> >*) = 0;

    63 protected:

    64   virtual ~MediaEngine() {}

    65 };

    67 /**

    68  * Common abstract base class for audio and video sources.

    69  */

    70 class MediaEngineSource : public nsISupports

    71 {

    72 public:

    73   virtual ~MediaEngineSource() {}

    75   /* Populate the human readable name of this device in the nsAString */

    76   virtual void GetName(nsAString&) = 0;

    78   /* Populate the UUID of this device in the nsAString */

    79   virtual void GetUUID(nsAString&) = 0;

    81   /* Release the device back to the system. */

    82   virtual nsresult Deallocate() = 0;

    84   /* Start the device and add the track to the provided SourceMediaStream, with

    85    * the provided TrackID. You may start appending data to the track

    86    * immediately after. */

    87   virtual nsresult Start(SourceMediaStream*, TrackID) = 0;

    89   /* Take a snapshot from this source. In the case of video this is a single

    90    * image, and for audio, it is a snippet lasting aDuration milliseconds. The

    91    * duration argument is ignored for a MediaEngineVideoSource.

    92    */

    93   virtual nsresult Snapshot(uint32_t aDuration, nsIDOMFile** aFile) = 0;

    95   /* Called when the stream wants more data */

    96   virtual void NotifyPull(MediaStreamGraph* aGraph,

    97                           SourceMediaStream *aSource,

    98                           TrackID aId,

    99                           StreamTime aDesiredTime,

   100                           TrackTicks &aLastEndTime) = 0;

   102   /* Stop the device and release the corresponding MediaStream */

   103   virtual nsresult Stop(SourceMediaStream *aSource, TrackID aID) = 0;

   105   /* Change device configuration.  */

   106   virtual nsresult Config(bool aEchoOn, uint32_t aEcho,

   107                           bool aAgcOn, uint32_t aAGC,

   108                           bool aNoiseOn, uint32_t aNoise,

   109                           int32_t aPlayoutDelay) = 0;

   111   /* Returns true if a source represents a fake capture device and

   112    * false otherwise

   113    */

   114   virtual bool IsFake() = 0;

   116   /* Return false if device is currently allocated or started */

   117   bool IsAvailable() {

   118     if (mState == kAllocated || mState == kStarted) {

   119       return false;

   120     } else {

   121       return true;

   122     }

   123   }

   125   /* It is an error to call Start() before an Allocate(), and Stop() before

   126    * a Start(). Only Allocate() may be called after a Deallocate(). */

   128 protected:

   129   MediaEngineState mState;

   130 };

   132 /**

   133  * Video source and friends.

   134  */

   135 class MediaEnginePrefs {

   136 public:

   137   int32_t mWidth;

   138   int32_t mHeight;

   139   int32_t mFPS;

   140   int32_t mMinFPS;

   142   // mWidth and/or mHeight may be zero (=adaptive default), so use functions.

   144   int32_t GetWidth(bool aHD = false) const {

   145     return mWidth? mWidth : (mHeight?

   146                              (mHeight * GetDefWidth(aHD)) / GetDefHeight(aHD) :

   147                              GetDefWidth(aHD));

   148   }

   150   int32_t GetHeight(bool aHD = false) const {

   151     return mHeight? mHeight : (mWidth?

   152                                (mWidth * GetDefHeight(aHD)) / GetDefWidth(aHD) :

   153                                GetDefHeight(aHD));

   154   }

   155 private:

   156   static int32_t GetDefWidth(bool aHD = false) {

   157     return aHD ? MediaEngine::DEFAULT_169_VIDEO_WIDTH :

   158                  MediaEngine::DEFAULT_43_VIDEO_WIDTH;

   159   }

   161   static int32_t GetDefHeight(bool aHD = false) {

   162     return aHD ? MediaEngine::DEFAULT_169_VIDEO_HEIGHT :

   163                  MediaEngine::DEFAULT_43_VIDEO_HEIGHT;

   164   }

   165 };

   167 class MediaEngineVideoSource : public MediaEngineSource

   168 {

   169 public:

   170   virtual ~MediaEngineVideoSource() {}

   172   /* This call reserves but does not start the device. */

   173   virtual nsresult Allocate(const VideoTrackConstraintsN &aConstraints,

   174                             const MediaEnginePrefs &aPrefs) = 0;

   175 };

   177 /**

   178  * Audio source and friends.

   179  */

   180 class MediaEngineAudioSource : public MediaEngineSource

   181 {

   182 public:

   183   virtual ~MediaEngineAudioSource() {}

   185   /* This call reserves but does not start the device. */

   186   virtual nsresult Allocate(const AudioTrackConstraintsN &aConstraints,

   187                             const MediaEnginePrefs &aPrefs) = 0;

   189 };

   191 }

   193 #endif /* MEDIAENGINE_H_ */

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