components/scheduler/renderer/deadline_task_runner.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 COMPONENTS_SCHEDULER_RENDERER_DEADLINE_TASK_RUNNER_H_
   6 #define COMPONENTS_SCHEDULER_RENDERER_DEADLINE_TASK_RUNNER_H_
   7
   8 #include "base/callback.h"
   9 #include "base/macros.h"
  10 #include "base/memory/weak_ptr.h"
  11 #include "base/single_thread_task_runner.h"
  12 #include "base/time/time.h"
  13 #include "components/scheduler/child/cancelable_closure_holder.h"
  14 #include "components/scheduler/scheduler_export.h"
  15
  16 namespace scheduler {
  17
  18 // Runs a posted task at latest by a given deadline, but possibly sooner.
  19 class SCHEDULER_EXPORT DeadlineTaskRunner {
  20  public:
  21   DeadlineTaskRunner(const base::Closure& callback,
  22                      scoped_refptr<base::SingleThreadTaskRunner> task_runner);
  23
  24   ~DeadlineTaskRunner();
  25
  26   // If there is no outstanding task then a task is posted to run after |delay|.
  27   // If there is an outstanding task which is scheduled to run:
  28   //   a) sooner - then this is a NOP.
  29   //   b) later - then the outstanding task is cancelled and a new task is
  30   //              posted to run after |delay|.
  31   //
  32   // Once the deadline task has run, we reset.
  33   void SetDeadline(const tracked_objects::Location& from_here,
  34                    base::TimeDelta delay,
  35                    base::TimeTicks now);
  36
  37  private:
  38   void RunInternal();
  39
  40   CancelableClosureHolder cancelable_run_internal_;
  41   base::Closure callback_;
  42   base::TimeTicks deadline_;
  43   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
  44
  45   DISALLOW_COPY_AND_ASSIGN(DeadlineTaskRunner);
  46 };
  47
  48 }  // namespace scheduler
  49
  50 #endif  // COMPONENTS_SCHEDULER_RENDERER_DEADLINE_TASK_RUNNER_H_