image/AnimationSurfaceProvider.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 /**
   7  * An ISurfaceProvider for animated images.
   8  */
   9
  10 #ifndef mozilla_image_AnimationSurfaceProvider_h
  11 #define mozilla_image_AnimationSurfaceProvider_h
  12
  13 #include "mozilla/UniquePtr.h"
  14
  15 #include "Decoder.h"
  16 #include "FrameAnimator.h"
  17 #include "IDecodingTask.h"
  18 #include "ISurfaceProvider.h"
  19 #include "AnimationFrameBuffer.h"
  20
  21 namespace mozilla {
  22 namespace image {
  23
  24 /**
  25  * An ISurfaceProvider that manages the decoding of animated images and
  26  * dynamically generates surfaces for the current playback state of the
  27  * animation.
  28  */
  29 class AnimationSurfaceProvider final : public ISurfaceProvider,
  30                                        public IDecodingTask,
  31                                        public IDecoderFrameRecycler {
  32  public:
  33   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(AnimationSurfaceProvider, override)
  34
  35   AnimationSurfaceProvider(NotNull<RasterImage*> aImage,
  36                            const SurfaceKey& aSurfaceKey,
  37                            NotNull<Decoder*> aDecoder, size_t aCurrentFrame);
  38
  39   //////////////////////////////////////////////////////////////////////////////
  40   // ISurfaceProvider implementation.
  41   //////////////////////////////////////////////////////////////////////////////
  42
  43  public:
  44   // We use the ISurfaceProvider constructor of DrawableSurface to indicate that
  45   // our surfaces are computed lazily.
  46   DrawableSurface Surface() override {
  47     return DrawableSurface(WrapNotNull(this));
  48   }
  49
  50   bool IsFinished() const override;
  51   bool IsFullyDecoded() const override;
  52   size_t LogicalSizeInBytes() const override;
  53   void AddSizeOfExcludingThis(MallocSizeOf aMallocSizeOf,
  54                               const AddSizeOfCb& aCallback) override;
  55   void Reset() override;
  56   void Advance(size_t aFrame) override;
  57
  58  protected:
  59   DrawableFrameRef DrawableRef(size_t aFrame) override;
  60   already_AddRefed<imgFrame> GetFrame(size_t aFrame) override;
  61
  62   // Animation frames are always locked. This is because we only want to release
  63   // their memory atomically (due to the surface cache discarding them). If they
  64   // were unlocked, the OS could end up releasing the memory of random frames
  65   // from the middle of the animation, which is not worth the complexity of
  66   // dealing with.
  67   bool IsLocked() const override { return true; }
  68   void SetLocked(bool) override {}
  69
  70   //////////////////////////////////////////////////////////////////////////////
  71   // IDecodingTask implementation.
  72   //////////////////////////////////////////////////////////////////////////////
  73
  74  public:
  75   void Run() override;
  76   bool ShouldPreferSyncRun() const override;
  77
  78   // Full decodes are low priority compared to metadata decodes because they
  79   // don't block layout or page load.
  80   TaskPriority Priority() const override { return TaskPriority::eLow; }
  81
  82   //////////////////////////////////////////////////////////////////////////////
  83   // IDecoderFrameRecycler implementation.
  84   //////////////////////////////////////////////////////////////////////////////
  85
  86  public:
  87   RawAccessFrameRef RecycleFrame(gfx::IntRect& aRecycleRect) override;
  88
  89  private:
  90   virtual ~AnimationSurfaceProvider();
  91
  92   void DropImageReference();
  93   void AnnounceSurfaceAvailable();
  94   void FinishDecoding();
  95   void RequestFrameDiscarding();
  96
  97   // @returns Whether or not we should continue decoding.
  98   bool CheckForNewFrameAtYield();
  99
 100   // @returns Whether or not we should restart decoding.
 101   bool CheckForNewFrameAtTerminalState();
 102
 103   /// The image associated with our decoder.
 104   RefPtr<RasterImage> mImage;
 105
 106   /// A mutex to protect mDecoder. Always taken before mFramesMutex.
 107   mutable Mutex mDecodingMutex;
 108
 109   /// The decoder used to decode this animation.
 110   RefPtr<Decoder> mDecoder;
 111
 112   /// A mutex to protect mFrames. Always taken after mDecodingMutex.
 113   mutable Mutex mFramesMutex;
 114
 115   /// The frames of this animation, in order.
 116   UniquePtr<AnimationFrameBuffer> mFrames;
 117 };
 118
 119 }  // namespace image
 120 }  // namespace mozilla
 121
 122 #endif  // mozilla_image_AnimationSurfaceProvider_h