cc/tiles/image_controller.h - chromium/src - Git at Google

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 #ifndef CC_TILES_IMAGE_CONTROLLER_H_
 #define CC_TILES_IMAGE_CONTROLLER_H_

 #include <set>
 #include <vector>

 #include "base/callback.h"
 #include "base/containers/flat_map.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "base/sequenced_task_runner.h"
 #include "base/threading/simple_thread.h"
 #include "cc/base/unique_notifier.h"
 #include "cc/cc_export.h"
 #include "cc/paint/draw_image.h"
 #include "cc/raster/tile_task.h"
 #include "cc/tiles/image_decode_cache.h"

 namespace cc {

 class CC_EXPORT ImageController {
  public:
   enum class ImageDecodeResult { SUCCESS, DECODE_NOT_REQUIRED, FAILURE };

   using ImageDecodeRequestId = uint64_t;
   using ImageDecodedCallback =
       base::OnceCallback<void(ImageDecodeRequestId, ImageDecodeResult)>;
   explicit ImageController(
       base::SequencedTaskRunner* origin_task_runner,
       scoped_refptr<base::SequencedTaskRunner> worker_task_runner);
   ImageController(const ImageController&) = delete;
   virtual ~ImageController();

   ImageController& operator=(const ImageController&) = delete;

   void SetImageDecodeCache(ImageDecodeCache* cache);
   // Build tile tasks for synchronously decoded images.
   // |sync_decoded_images| is the input. These are the images from a particular
   // tile, retrieved by the DiscardableImageMap. Images can be removed from the
   // vector under certain conditions.
   // |tasks| is an output, which are the built tile tasks.
   // |has_at_raster_images| is an output parameter.
   // |has_hardware_accelerated_jpeg_candidates| and
   // |has_hardware_accelerated_webp_candidates| are output parameters that
   // indicate if there are images in |sync_decoded_images| that could be decoded
   // using hardware decode acceleration.
   // |tracing_info| is used in tracing or UMA only.
   void ConvertImagesToTasks(std::vector<DrawImage>* sync_decoded_images,
                             std::vector<scoped_refptr<TileTask>>* tasks,
                             bool* has_at_raster_images,
                             bool* has_hardware_accelerated_jpeg_candidates,
                             bool* has_hardware_accelerated_webp_candidates,
                             const ImageDecodeCache::TracingInfo& tracing_info);
   void UnrefImages(const std::vector<DrawImage>& images);
   void ReduceMemoryUsage();
   std::vector<scoped_refptr<TileTask>> SetPredecodeImages(
       std::vector<DrawImage> predecode_images,
       const ImageDecodeCache::TracingInfo& tracing_info);

   // Virtual for testing.
   virtual void UnlockImageDecode(ImageDecodeRequestId id);

   // This function requests that the given image be decoded and locked. Once the
   // callback has been issued, it is passed an ID, which should be used to
   // unlock this image. It is up to the caller to ensure that the image is later
   // unlocked using UnlockImageDecode.
   // Virtual for testing.
   virtual ImageDecodeRequestId QueueImageDecode(const DrawImage& draw_image,
                                                 ImageDecodedCallback callback);
   size_t image_cache_max_limit_bytes() const {
     return image_cache_max_limit_bytes_;
   }

   void SetMaxImageCacheLimitBytesForTesting(size_t bytes) {
     image_cache_max_limit_bytes_ = bytes;
   }

   ImageDecodeCache* cache() const { return cache_; }

  protected:
   scoped_refptr<base::SequencedTaskRunner> worker_task_runner_;

  private:
   struct ImageDecodeRequest {
     ImageDecodeRequest();
     ImageDecodeRequest(ImageDecodeRequestId id,
                        const DrawImage& draw_image,
                        ImageDecodedCallback callback,
                        scoped_refptr<TileTask> task,
                        bool need_unref);
     ImageDecodeRequest(ImageDecodeRequest&& other);
     ~ImageDecodeRequest();

     ImageDecodeRequest& operator=(ImageDecodeRequest&& other);

     ImageDecodeRequestId id;
     DrawImage draw_image;
     ImageDecodedCallback callback;
     scoped_refptr<TileTask> task;
     bool need_unref;
   };

   void StopWorkerTasks();

   // Called from the worker thread.
   void ProcessNextImageDecodeOnWorkerThread();

   void ImageDecodeCompleted(ImageDecodeRequestId id);
   void GenerateTasksForOrphanedRequests();

   base::WeakPtr<ImageController> weak_ptr_;

   ImageDecodeCache* cache_ = nullptr;
   std::vector<DrawImage> predecode_locked_images_;

   static ImageDecodeRequestId s_next_image_decode_queue_id_;
   base::flat_map<ImageDecodeRequestId, DrawImage> requested_locked_images_;

   base::SequencedTaskRunner* origin_task_runner_ = nullptr;
   size_t image_cache_max_limit_bytes_ = 0u;

   // The variables defined below this lock (aside from weak_ptr_factory_) can
   // only be accessed when the lock is acquired.
   base::Lock lock_;
   std::map<ImageDecodeRequestId, ImageDecodeRequest> image_decode_queue_;
   std::map<ImageDecodeRequestId, ImageDecodeRequest>
       requests_needing_completion_;
   bool abort_tasks_ = false;
   // Orphaned requests are requests that were either in queue or needed a
   // completion callback when we set the decode cache to be nullptr. When a new
   // decode cache is set, these requests are re-enqueued again with tasks
   // generated by the new cache. Note that when the cache is set, then aside
   // from generating new tasks, this vector should be empty.
   std::vector<ImageDecodeRequest> orphaned_decode_requests_;

   base::WeakPtrFactory<ImageController> weak_ptr_factory_{this};
 };

 }  // namespace cc

 #endif  // CC_TILES_IMAGE_CONTROLLER_H_
	// Copyright 2016 The Chromium Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	#ifndef CC_TILES_IMAGE_CONTROLLER_H_
	#define CC_TILES_IMAGE_CONTROLLER_H_

	#include <set>
	#include <vector>

	#include "base/callback.h"
	#include "base/containers/flat_map.h"
	#include "base/memory/ref_counted.h"
	#include "base/memory/weak_ptr.h"
	#include "base/sequenced_task_runner.h"
	#include "base/threading/simple_thread.h"
	#include "cc/base/unique_notifier.h"
	#include "cc/cc_export.h"
	#include "cc/paint/draw_image.h"
	#include "cc/raster/tile_task.h"
	#include "cc/tiles/image_decode_cache.h"

	namespace cc {

	class CC_EXPORT ImageController {
	public:
	enum class ImageDecodeResult { SUCCESS, DECODE_NOT_REQUIRED, FAILURE };

	using ImageDecodeRequestId = uint64_t;
	using ImageDecodedCallback =
	base::OnceCallback<void(ImageDecodeRequestId, ImageDecodeResult)>;
	explicit ImageController(
	base::SequencedTaskRunner* origin_task_runner,
	scoped_refptr<base::SequencedTaskRunner> worker_task_runner);
	ImageController(const ImageController&) = delete;
	virtual ~ImageController();

	ImageController& operator=(const ImageController&) = delete;

	void SetImageDecodeCache(ImageDecodeCache* cache);
	// Build tile tasks for synchronously decoded images.
	// \|sync_decoded_images\| is the input. These are the images from a particular
	// tile, retrieved by the DiscardableImageMap. Images can be removed from the
	// vector under certain conditions.
	// \|tasks\| is an output, which are the built tile tasks.
	// \|has_at_raster_images\| is an output parameter.
	// \|has_hardware_accelerated_jpeg_candidates\| and
	// \|has_hardware_accelerated_webp_candidates\| are output parameters that
	// indicate if there are images in \|sync_decoded_images\| that could be decoded
	// using hardware decode acceleration.
	// \|tracing_info\| is used in tracing or UMA only.
	void ConvertImagesToTasks(std::vector<DrawImage>* sync_decoded_images,
	std::vector<scoped_refptr<TileTask>>* tasks,
	bool* has_at_raster_images,
	bool* has_hardware_accelerated_jpeg_candidates,
	bool* has_hardware_accelerated_webp_candidates,
	const ImageDecodeCache::TracingInfo& tracing_info);
	void UnrefImages(const std::vector<DrawImage>& images);
	void ReduceMemoryUsage();
	std::vector<scoped_refptr<TileTask>> SetPredecodeImages(
	std::vector<DrawImage> predecode_images,
	const ImageDecodeCache::TracingInfo& tracing_info);

	// Virtual for testing.
	virtual void UnlockImageDecode(ImageDecodeRequestId id);

	// This function requests that the given image be decoded and locked. Once the
	// callback has been issued, it is passed an ID, which should be used to
	// unlock this image. It is up to the caller to ensure that the image is later
	// unlocked using UnlockImageDecode.
	// Virtual for testing.
	virtual ImageDecodeRequestId QueueImageDecode(const DrawImage& draw_image,
	ImageDecodedCallback callback);
	size_t image_cache_max_limit_bytes() const {
	return image_cache_max_limit_bytes_;
	}

	void SetMaxImageCacheLimitBytesForTesting(size_t bytes) {
	image_cache_max_limit_bytes_ = bytes;
	}

	ImageDecodeCache* cache() const { return cache_; }

	protected:
	scoped_refptr<base::SequencedTaskRunner> worker_task_runner_;

	private:
	struct ImageDecodeRequest {
	ImageDecodeRequest();
	ImageDecodeRequest(ImageDecodeRequestId id,
	const DrawImage& draw_image,
	ImageDecodedCallback callback,
	scoped_refptr<TileTask> task,
	bool need_unref);
	ImageDecodeRequest(ImageDecodeRequest&& other);
	~ImageDecodeRequest();

	ImageDecodeRequest& operator=(ImageDecodeRequest&& other);

	ImageDecodeRequestId id;
	DrawImage draw_image;
	ImageDecodedCallback callback;
	scoped_refptr<TileTask> task;
	bool need_unref;
	};

	void StopWorkerTasks();

	// Called from the worker thread.
	void ProcessNextImageDecodeOnWorkerThread();

	void ImageDecodeCompleted(ImageDecodeRequestId id);
	void GenerateTasksForOrphanedRequests();

	base::WeakPtr<ImageController> weak_ptr_;

	ImageDecodeCache* cache_ = nullptr;
	std::vector<DrawImage> predecode_locked_images_;

	static ImageDecodeRequestId s_next_image_decode_queue_id_;
	base::flat_map<ImageDecodeRequestId, DrawImage> requested_locked_images_;

	base::SequencedTaskRunner* origin_task_runner_ = nullptr;
	size_t image_cache_max_limit_bytes_ = 0u;

	// The variables defined below this lock (aside from weak_ptr_factory_) can
	// only be accessed when the lock is acquired.
	base::Lock lock_;
	std::map<ImageDecodeRequestId, ImageDecodeRequest> image_decode_queue_;
	std::map<ImageDecodeRequestId, ImageDecodeRequest>
	requests_needing_completion_;
	bool abort_tasks_ = false;
	// Orphaned requests are requests that were either in queue or needed a
	// completion callback when we set the decode cache to be nullptr. When a new
	// decode cache is set, these requests are re-enqueued again with tasks
	// generated by the new cache. Note that when the cache is set, then aside
	// from generating new tasks, this vector should be empty.
	std::vector<ImageDecodeRequest> orphaned_decode_requests_;

	base::WeakPtrFactory<ImageController> weak_ptr_factory_{this};
	};

	} // namespace cc

	#endif // CC_TILES_IMAGE_CONTROLLER_H_