base/pending_task.h

   1 // Copyright (c) 2011 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 PENDING_TASK_H_
   6 #define PENDING_TASK_H_
   7 #pragma once
   8
   9 #include <queue>
  10
  11 #include "base/base_export.h"
  12 #include "base/callback.h"
  13 #include "base/location.h"
  14 #include "base/time.h"
  15 #include "base/tracking_info.h"
  16
  17 namespace base {
  18
  19 // Contains data about a pending task. Stored in TaskQueue and DelayedTaskQueue
  20 // for use by classes that queue and execute tasks.
  21 struct BASE_EXPORT PendingTask : public TrackingInfo {
  22   PendingTask(const tracked_objects::Location& posted_from,
  23               const Closure& task);
  24   PendingTask(const tracked_objects::Location& posted_from,
  25               const Closure& task,
  26               TimeTicks delayed_run_time,
  27               bool nestable);
  28   ~PendingTask();
  29
  30   // Used to support sorting.
  31   bool operator<(const PendingTask& other) const;
  32
  33   // The task to run.
  34   Closure task;
  35
  36   // The site this PendingTask was posted from.
  37   tracked_objects::Location posted_from;
  38
  39   // Secondary sort key for run time.
  40   int sequence_num;
  41
  42   // OK to dispatch from a nested loop.
  43   bool nestable;
  44 };
  45
  46 // Wrapper around std::queue specialized for PendingTask which adds a Swap
  47 // helper method.
  48 class BASE_EXPORT TaskQueue : public std::queue<PendingTask> {
  49  public:
  50   void Swap(TaskQueue* queue);
  51 };
  52
  53 // PendingTasks are sorted by their |delayed_run_time| property.
  54 typedef std::priority_queue<base::PendingTask> DelayedTaskQueue;
  55
  56 }  // namespace base
  57
  58 #endif  // PENDING_TASK_H_