cc/resources/raster_worker_pool.h

// Copyright 2013 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_RESOURCES_RASTER_WORKER_POOL_H_
#define CC_RESOURCES_RASTER_WORKER_POOL_H_

#include "cc/resources/rasterizer.h"

namespace base {
class SequencedTaskRunner;
}

namespace cc {

class CC_EXPORT RasterWorkerPool {
 public:
  static unsigned kOnDemandRasterTaskPriority;
  static unsigned kBenchmarkRasterTaskPriority;
  static unsigned kRasterFinishedTaskPriority;
  static unsigned kRasterRequiredForActivationFinishedTaskPriority;
  static unsigned kRasterTaskPriorityBase;

  RasterWorkerPool();
  virtual ~RasterWorkerPool();

  // Set the number of threads to use for the global TaskGraphRunner instance.
  // This can only be called once and must be called prior to
  // GetNumRasterThreads().
  static void SetNumRasterThreads(int num_threads);

  // Returns the number of threads used for the global TaskGraphRunner instance.
  static int GetNumRasterThreads();

  // Returns a pointer to the global TaskGraphRunner instance.
  static TaskGraphRunner* GetTaskGraphRunner();

  // Returns a unique clone index for the current thread. Guaranteed to be a
  // value between 0 and GetNumRasterThreads() - 1.
  static size_t GetPictureCloneIndexForCurrentThread();

  // Utility function that can be used to create a "raster finished" task that
  // posts |callback| to |task_runner| when run.
  static scoped_refptr<RasterizerTask> CreateRasterFinishedTask(
      base::SequencedTaskRunner* task_runner,
      const base::Closure& callback);

  // Utility function that can be used to create a "raster required for
  // activation finished" task that posts |callback| to |task_runner| when run.
  static scoped_refptr<RasterizerTask>
      CreateRasterRequiredForActivationFinishedTask(
          size_t tasks_required_for_activation_count,
          base::SequencedTaskRunner* task_runner,
          const base::Closure& callback);

  // Utility function that can be used to call ::ScheduleOnOriginThread() for
  // each task in |graph|.
  static void ScheduleTasksOnOriginThread(RasterizerTaskClient* client,
                                          TaskGraph* graph);

  // Utility function that can be used to build a task graph. Inserts a node
  // that represents |task| in |graph|. See TaskGraph definition for valid
  // |priority| values.
  static void InsertNodeForTask(TaskGraph* graph,
                                RasterizerTask* task,
                                unsigned priority,
                                size_t dependencies);

  // Utility function that can be used to build a task graph. Inserts nodes that
  // represent |task| and all its image decode dependencies in |graph|.
  static void InsertNodesForRasterTask(
      TaskGraph* graph,
      RasterTask* task,
      const ImageDecodeTask::Vector& decode_tasks,
      unsigned priority);

  // Type-checking downcast routine.
  virtual Rasterizer* AsRasterizer() = 0;
};

}  // namespace cc

#endif  // CC_RESOURCES_RASTER_WORKER_POOL_H_