components/scheduler/child/single_thread_idle_task_runner.h

   1 // Copyright 2014 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_CHILD_SINGLE_THREAD_IDLE_TASK_RUNNER_H_
   6 #define COMPONENTS_SCHEDULER_CHILD_SINGLE_THREAD_IDLE_TASK_RUNNER_H_
   7
   8 #include "base/bind.h"
   9 #include "base/callback.h"
  10 #include "base/memory/ref_counted.h"
  11 #include "base/single_thread_task_runner.h"
  12 #include "base/time/time.h"
  13 #include "components/scheduler/scheduler_export.h"
  14
  15 namespace scheduler {
  16
  17 // A SingleThreadIdleTaskRunner is a task runner for running idle tasks. Idle
  18 // tasks have an unbound argument which is bound to a deadline
  19 // (in base::TimeTicks) when they are run. The idle task is expected to
  20 // complete by this deadline.
  21 class SingleThreadIdleTaskRunner
  22     : public base::RefCountedThreadSafe<SingleThreadIdleTaskRunner> {
  23  public:
  24   typedef base::Callback<void(base::TimeTicks)> IdleTask;
  25
  26   // Used to request idle task deadlines and signal posting of idle tasks.
  27   class SCHEDULER_EXPORT Delegate {
  28    public:
  29     Delegate();
  30     virtual ~Delegate();
  31
  32     // Signals that an idle task has been posted. This will be called on the
  33     // posting thread, which may not be the same thread as the
  34     // SingleThreadIdleTaskRunner runs on.
  35     virtual void OnIdleTaskPosted() = 0;
  36
  37     // Signals that a new idle task is about to be run and returns the deadline
  38     // for this idle task.
  39     virtual base::TimeTicks WillProcessIdleTask() = 0;
  40
  41     // Signals that an idle task has finished being run.
  42     virtual void DidProcessIdleTask() = 0;
  43
  44    private:
  45     DISALLOW_COPY_AND_ASSIGN(Delegate);
  46   };
  47
  48   // NOTE Category strings must have application lifetime (statics or
  49   // literals). They may not include " chars.
  50   SingleThreadIdleTaskRunner(
  51       scoped_refptr<base::SingleThreadTaskRunner> idle_priority_task_runner,
  52       scoped_refptr<base::SingleThreadTaskRunner> after_wakeup_task_runner,
  53       Delegate* Delegate,
  54       const char* tracing_category);
  55
  56   virtual void PostIdleTask(const tracked_objects::Location& from_here,
  57                             const IdleTask& idle_task);
  58
  59   virtual void PostNonNestableIdleTask(
  60       const tracked_objects::Location& from_here,
  61       const IdleTask& idle_task);
  62
  63   virtual void PostIdleTaskAfterWakeup(
  64       const tracked_objects::Location& from_here,
  65       const IdleTask& idle_task);
  66
  67   bool RunsTasksOnCurrentThread() const;
  68
  69  protected:
  70   virtual ~SingleThreadIdleTaskRunner();
  71
  72  private:
  73   friend class base::RefCountedThreadSafe<SingleThreadIdleTaskRunner>;
  74
  75   void RunTask(IdleTask idle_task);
  76
  77   scoped_refptr<base::SingleThreadTaskRunner> idle_priority_task_runner_;
  78   scoped_refptr<base::SingleThreadTaskRunner> after_wakeup_task_runner_;
  79   Delegate* delegate_;  // NOT OWNED
  80   const char* tracing_category_;
  81   base::WeakPtr<SingleThreadIdleTaskRunner> weak_scheduler_ptr_;
  82   base::WeakPtrFactory<SingleThreadIdleTaskRunner> weak_factory_;
  83   DISALLOW_COPY_AND_ASSIGN(SingleThreadIdleTaskRunner);
  84 };
  85
  86 }  // namespace scheduler
  87
  88 #endif  // COMPONENTS_SCHEDULER_CHILD_SINGLE_THREAD_IDLE_TASK_RUNNER_H_