content/renderer/raster_worker_pool.h

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CONTENT_RENDERER_RASTER_WORKER_POOL_H_
   6 #define CONTENT_RENDERER_RASTER_WORKER_POOL_H_
   7
   8 #include "base/callback.h"
   9 #include "base/containers/hash_tables.h"
  10 #include "base/memory/scoped_vector.h"
  11 #include "base/sequenced_task_runner.h"
  12 #include "base/task_runner.h"
  13 #include "base/threading/simple_thread.h"
  14 #include "cc/raster/task_graph_runner.h"
  15 #include "content/common/content_export.h"
  16
  17 namespace content {
  18
  19 // A pool of threads used to run raster work.
  20 // Work can be scheduled on the threads using different interfaces.
  21 // The pool itself implements TaskRunner interface and tasks posted via that
  22 // interface might run in parallel.
  23 // CreateSequencedTaskRunner creates a sequenced task runner that might run in
  24 // parallel with other instances of sequenced task runners.
  25 // It's also possible to get the underlying TaskGraphRunner to schedule a graph
  26 // of tasks with their dependencies.
  27 // TODO(reveman): make TaskGraphRunner an abstract interface and have this
  28 // WorkerPool class implement it.
  29 class CONTENT_EXPORT RasterWorkerPool
  30     : public base::TaskRunner,
  31       public base::DelegateSimpleThread::Delegate {
  32  public:
  33   RasterWorkerPool();
  34
  35   // Overridden from base::TaskRunner:
  36   bool PostDelayedTask(const tracked_objects::Location& from_here,
  37                        const base::Closure& task,
  38                        base::TimeDelta delay) override;
  39   bool RunsTasksOnCurrentThread() const override;
  40
  41   // Overridden from base::DelegateSimpleThread::Delegate:
  42   void Run() override;
  43
  44   // Spawn |num_threads| number of threads and start running work on the
  45   // worker threads.
  46   void Start(int num_threads,
  47              const base::SimpleThread::Options& thread_options);
  48
  49   // Finish running all the posted tasks (and nested task posted by those tasks)
  50   // of all the associated task runners.
  51   // Once all the tasks are executed the method blocks until the threads are
  52   // terminated.
  53   void Shutdown();
  54
  55   cc::TaskGraphRunner* GetTaskGraphRunner() { return &task_graph_runner_; }
  56
  57   // Create a new sequenced task graph runner.
  58   scoped_refptr<base::SequencedTaskRunner> CreateSequencedTaskRunner();
  59
  60  protected:
  61   ~RasterWorkerPool() override;
  62
  63  private:
  64   class RasterWorkerPoolSequencedTaskRunner;
  65   friend class RasterWorkerPoolSequencedTaskRunner;
  66
  67   // Simple Task for the TaskGraphRunner that wraps a closure.
  68   // This class is used to schedule TaskRunner tasks on the
  69   // |task_graph_runner_|.
  70   class ClosureTask : public cc::Task {
  71    public:
  72     explicit ClosureTask(const base::Closure& closure);
  73
  74     // Overridden from cc::Task:
  75     void RunOnWorkerThread() override;
  76
  77    protected:
  78     ~ClosureTask() override;
  79
  80    private:
  81     base::Closure closure_;
  82
  83     DISALLOW_COPY_AND_ASSIGN(ClosureTask);
  84   };
  85
  86   // The actual threads where work is done.
  87   ScopedVector<base::DelegateSimpleThread> threads_;
  88   cc::TaskGraphRunner task_graph_runner_;
  89
  90   // Lock to exclusively access all the following members that are used to
  91   // implement the TaskRunner interfaces.
  92   base::Lock lock_;
  93   // Namespace used to schedule tasks in the task graph runner.
  94   cc::NamespaceToken namespace_token_;
  95   // List of tasks currently queued up for execution.
  96   cc::Task::Vector tasks_;
  97   // Graph object used for scheduling tasks.
  98   cc::TaskGraph graph_;
  99   // Cached vector to avoid allocation when getting the list of complete
 100   // tasks.
 101   cc::Task::Vector completed_tasks_;
 102 };
 103
 104 }  // namespace content
 105
 106 #endif  // CONTENT_RENDERER_RASTER_WORKER_POOL_H_