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