image/DecodedSurfaceProvider.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 implemented for single-frame decoded surfaces.
   8  */
   9
  10 #ifndef mozilla_image_DecodedSurfaceProvider_h
  11 #define mozilla_image_DecodedSurfaceProvider_h
  12
  13 #include "IDecodingTask.h"
  14 #include "ISurfaceProvider.h"
  15 #include "SurfaceCache.h"
  16
  17 namespace mozilla {
  18 namespace image {
  19
  20 /**
  21  * An ISurfaceProvider that manages the decoding of a single-frame image and
  22  * stores the resulting surface.
  23  */
  24 class DecodedSurfaceProvider final : public ISurfaceProvider,
  25                                      public IDecodingTask {
  26  public:
  27   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(DecodedSurfaceProvider, override)
  28
  29   DecodedSurfaceProvider(NotNull<RasterImage*> aImage,
  30                          const SurfaceKey& aSurfaceKey,
  31                          NotNull<Decoder*> aDecoder);
  32
  33   //////////////////////////////////////////////////////////////////////////////
  34   // ISurfaceProvider implementation.
  35   //////////////////////////////////////////////////////////////////////////////
  36
  37  public:
  38   bool IsFinished() const override;
  39   size_t LogicalSizeInBytes() const override;
  40
  41  protected:
  42   DrawableFrameRef DrawableRef(size_t aFrame) override;
  43   bool IsLocked() const override { return bool(mLockRef); }
  44   void SetLocked(bool aLocked) override;
  45
  46   //////////////////////////////////////////////////////////////////////////////
  47   // IDecodingTask implementation.
  48   //////////////////////////////////////////////////////////////////////////////
  49
  50  public:
  51   void Run() override;
  52   bool ShouldPreferSyncRun() const override;
  53
  54   // Full decodes are low priority compared to metadata decodes because they
  55   // don't block layout or page load.
  56   TaskPriority Priority() const override { return TaskPriority::eLow; }
  57
  58  private:
  59   virtual ~DecodedSurfaceProvider();
  60
  61   void DropImageReference();
  62   void CheckForNewSurface();
  63   void FinishDecoding();
  64
  65   /// The image associated with our decoder. Dropped after decoding.
  66   RefPtr<RasterImage> mImage;
  67
  68   /// Mutex protecting access to mDecoder.
  69   Mutex mMutex;
  70
  71   /// The decoder that will generate our surface. Dropped after decoding.
  72   RefPtr<Decoder> mDecoder;
  73
  74   /// Our surface. Initially null until it's generated by the decoder.
  75   RefPtr<imgFrame> mSurface;
  76
  77   /// A drawable reference to our service; used for locking.
  78   DrawableFrameRef mLockRef;
  79 };
  80
  81 }  // namespace image
  82 }  // namespace mozilla
  83
  84 #endif  // mozilla_image_DecodedSurfaceProvider_h