base/pending_task.cc

   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 #include "base/pending_task.h"
   6
   7 #include "base/tracked_objects.h"
   8
   9 namespace base {
  10
  11 PendingTask::PendingTask(const tracked_objects::Location& posted_from,
  12                          const base::Closure& task)
  13     : base::TrackingInfo(posted_from, TimeTicks()),
  14       task(task),
  15       posted_from(posted_from),
  16       sequence_num(0),
  17       nestable(true),
  18       is_high_res(false) {
  19 }
  20
  21 PendingTask::PendingTask(const tracked_objects::Location& posted_from,
  22                          const base::Closure& task,
  23                          TimeTicks delayed_run_time,
  24                          bool nestable)
  25     : base::TrackingInfo(posted_from, delayed_run_time),
  26       task(task),
  27       posted_from(posted_from),
  28       sequence_num(0),
  29       nestable(nestable),
  30       is_high_res(false) {
  31 }
  32
  33 PendingTask::~PendingTask() {
  34 }
  35
  36 bool PendingTask::operator<(const PendingTask& other) const {
  37   // Since the top of a priority queue is defined as the "greatest" element, we
  38   // need to invert the comparison here.  We want the smaller time to be at the
  39   // top of the heap.
  40
  41   if (delayed_run_time < other.delayed_run_time)
  42     return false;
  43
  44   if (delayed_run_time > other.delayed_run_time)
  45     return true;
  46
  47   // If the times happen to match, then we use the sequence number to decide.
  48   // Compare the difference to support integer roll-over.
  49   return (sequence_num - other.sequence_num) > 0;
  50 }
  51
  52 void TaskQueue::Swap(TaskQueue* queue) {
  53   c.swap(queue->c);  // Calls std::deque::swap.
  54 }
  55
  56 }  // namespace base