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			121 lines
		
	
	
	
		
			3.4 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			121 lines
		
	
	
	
		
			3.4 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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 * License, v. 2.0. If a copy of the MPL was not distributed with this
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 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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/**
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 * An interface for tasks which can execute on the ImageLib DecodePool, and
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 * various implementations.
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 */
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#ifndef mozilla_image_IDecodingTask_h
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#define mozilla_image_IDecodingTask_h
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#include "imgFrame.h"
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#include "mozilla/NotNull.h"
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#include "mozilla/RefPtr.h"
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#include "nsIEventTarget.h"
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#include "SourceBuffer.h"
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namespace mozilla {
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namespace image {
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class Decoder;
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class RasterImage;
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/// A priority hint that DecodePool can use when scheduling an IDecodingTask.
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enum class TaskPriority : uint8_t { eLow, eHigh };
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/**
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 * An interface for tasks which can execute on the ImageLib DecodePool.
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 */
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class IDecodingTask : public IResumable {
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 public:
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  /// Run the task.
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  virtual void Run() = 0;
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  /// @return true if, given the option, this task prefers to run synchronously.
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  virtual bool ShouldPreferSyncRun() const = 0;
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  /// @return a priority hint that DecodePool can use when scheduling this task.
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  virtual TaskPriority Priority() const = 0;
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  /// A default implementation of IResumable which resubmits the task to the
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  /// DecodePool. Subclasses can override this if they need different behavior.
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  void Resume() override;
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 protected:
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  virtual ~IDecodingTask() {}
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  /// Notify @aImage of @aDecoder's progress.
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  void NotifyProgress(NotNull<RasterImage*> aImage, NotNull<Decoder*> aDecoder);
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  /// Notify @aImage that @aDecoder has finished.
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  void NotifyDecodeComplete(NotNull<RasterImage*> aImage,
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                            NotNull<Decoder*> aDecoder);
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 private:
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  void EnsureHasEventTarget(NotNull<RasterImage*> aImage);
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  bool IsOnEventTarget() const;
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  nsCOMPtr<nsIEventTarget> mEventTarget;
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};
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/**
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 * An IDecodingTask implementation for metadata decodes of images.
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 */
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class MetadataDecodingTask final : public IDecodingTask {
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 public:
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  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(MetadataDecodingTask, override)
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  explicit MetadataDecodingTask(NotNull<Decoder*> aDecoder);
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  void Run() override;
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  // Metadata decodes are very fast (since they only need to examine an image's
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  // header) so there's no reason to refuse to run them synchronously if the
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  // caller will allow us to.
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  bool ShouldPreferSyncRun() const override { return true; }
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  // Metadata decodes run at the highest priority because they block layout and
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  // page load.
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  TaskPriority Priority() const override { return TaskPriority::eHigh; }
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 private:
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  virtual ~MetadataDecodingTask() {}
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  /// Mutex protecting access to mDecoder.
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  Mutex mMutex MOZ_UNANNOTATED;
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  NotNull<RefPtr<Decoder>> mDecoder;
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};
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/**
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 * An IDecodingTask implementation for anonymous decoders - that is, decoders
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 * with no associated Image object.
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 */
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class AnonymousDecodingTask final : public IDecodingTask {
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 public:
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  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(AnonymousDecodingTask, override)
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  explicit AnonymousDecodingTask(NotNull<Decoder*> aDecoder, bool aResumable);
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  void Run() override;
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  bool ShouldPreferSyncRun() const override { return true; }
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  TaskPriority Priority() const override { return TaskPriority::eLow; }
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  void Resume() override;
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 private:
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  virtual ~AnonymousDecodingTask() {}
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  NotNull<RefPtr<Decoder>> mDecoder;
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  bool mResumable;
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};
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}  // namespace image
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}  // namespace mozilla
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#endif  // mozilla_image_IDecodingTask_h
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