dom/camera/DOMCameraPreview.h

   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/. */
   4
   5 #ifndef DOM_CAMERA_DOMCAMERAPREVIEW_H
   6 #define DOM_CAMERA_DOMCAMERAPREVIEW_H
   7
   8 #include "nsCycleCollectionParticipant.h"
   9 #include "MediaStreamGraph.h"
  10 #include "StreamBuffer.h"
  11 #include "ICameraControl.h"
  12 #include "DOMMediaStream.h"
  13 #include "CameraPreviewMediaStream.h"
  14 #include "CameraCommon.h"
  15
  16 class nsGlobalWindow;
  17
  18 namespace mozilla {
  19
  20 typedef void (*FrameBuilder)(mozilla::layers::Image* aImage, void* aBuffer, uint32_t aWidth, uint32_t aHeight);
  21
  22 /**
  23  * DOMCameraPreview is only exposed to the DOM as an nsDOMMediaStream,
  24  * which is a cycle-collection participant already, and we don't
  25  * add any traceable fields here, so we don't need to declare any
  26  * more cycle-collection goop.
  27  */
  28 class DOMCameraPreview : public DOMMediaStream
  29 {
  30 protected:
  31   enum { TRACK_VIDEO = 1 };
  32
  33 public:
  34   DOMCameraPreview(nsGlobalWindow* aWindow, ICameraControl* aCameraControl,
  35                    uint32_t aWidth, uint32_t aHeight, uint32_t aFramesPerSecond = 30);
  36
  37   bool ReceiveFrame(void* aBuffer, ImageFormat aFormat, mozilla::FrameBuilder aBuilder);
  38   bool HaveEnoughBuffered();
  39
  40   void Start();   // called by the MediaStreamListener to start preview
  41   void Started(); // called by the CameraControl when preview is started
  42   void StopPreview(); // called by the MediaStreamListener to stop preview
  43   void Stopped(bool aForced = false);
  44                   // called by the CameraControl when preview is stopped
  45   void Error();   // something went wrong, NS_RELEASE needed
  46
  47   void SetStateStarted();
  48   void SetStateStopped();
  49
  50 protected:
  51   virtual ~DOMCameraPreview();
  52
  53   enum {
  54     STOPPED,
  55     STARTING,
  56     STARTED,
  57     STOPPING
  58   };
  59   uint32_t mState;
  60
  61   // Helper function, used in conjunction with the macro below, to make
  62   //  it easy to track state changes, which must happen only on the main
  63   //  thread.
  64   void
  65   SetState(uint32_t aNewState, const char* aFileOrFunc, int aLine)
  66   {
  67 #ifdef PR_LOGGING
  68     const char* states[] = { "stopped", "starting", "started", "stopping" };
  69     MOZ_ASSERT(mState < sizeof(states) / sizeof(states[0]));
  70     MOZ_ASSERT(aNewState < sizeof(states) / sizeof(states[0]));
  71     DOM_CAMERA_LOGI("SetState: (this=%p) '%s' --> '%s' : %s:%d\n", this, states[mState], states[aNewState], aFileOrFunc, aLine);
  72 #endif
  73
  74     NS_ASSERTION(NS_IsMainThread(), "Preview state set OFF OF main thread!");
  75     mState = aNewState;
  76   }
  77
  78   uint32_t mWidth;
  79   uint32_t mHeight;
  80   uint32_t mFramesPerSecond;
  81   CameraPreviewMediaStream* mInput;
  82   nsRefPtr<mozilla::layers::ImageContainer> mImageContainer;
  83   VideoSegment mVideoSegment;
  84   uint32_t mFrameCount;
  85   nsRefPtr<ICameraControl> mCameraControl;
  86
  87   // Raw pointer; AddListener() keeps the reference for us
  88   MediaStreamListener* mListener;
  89
  90 private:
  91   DOMCameraPreview(const DOMCameraPreview&) MOZ_DELETE;
  92   DOMCameraPreview& operator=(const DOMCameraPreview&) MOZ_DELETE;
  93 };
  94
  95 } // namespace mozilla
  96
  97 #define DOM_CAMERA_SETSTATE(newState)   SetState((newState), __func__, __LINE__)
  98
  99 #endif // DOM_CAMERA_DOMCAMERAPREVIEW_H