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 #if _MSC_VER >= 1700
  12 // This a temporary fix for compiling on VS2012. http://crbug.com/154744
  13 PendingTask::PendingTask() : sequence_num(-1), nestable(false) {
  14 }
  15 #endif
  16
  17 PendingTask::PendingTask(const tracked_objects::Location& posted_from,
  18                          const base::Closure& task)
  19     : base::TrackingInfo(posted_from, TimeTicks()),
  20       task(task),
  21       posted_from(posted_from),
  22       sequence_num(0),
  23       nestable(true) {
  24 }
  25
  26 PendingTask::PendingTask(const tracked_objects::Location& posted_from,
  27                          const base::Closure& task,
  28                          TimeTicks delayed_run_time,
  29                          bool nestable)
  30     : base::TrackingInfo(posted_from, delayed_run_time),
  31       task(task),
  32       posted_from(posted_from),
  33       sequence_num(0),
  34       nestable(nestable) {
  35 }
  36
  37 PendingTask::~PendingTask() {
  38 }
  39
  40 bool PendingTask::operator<(const PendingTask& other) const {
  41   // Since the top of a priority queue is defined as the "greatest" element, we
  42   // need to invert the comparison here.  We want the smaller time to be at the
  43   // top of the heap.
  44
  45   if (delayed_run_time < other.delayed_run_time)
  46     return false;
  47
  48   if (delayed_run_time > other.delayed_run_time)
  49     return true;
  50
  51   // If the times happen to match, then we use the sequence number to decide.
  52   // Compare the difference to support integer roll-over.
  53   return (sequence_num - other.sequence_num) > 0;
  54 }
  55
  56 void TaskQueue::Swap(TaskQueue* queue) {
  57   c.swap(queue->c);  // Calls std::deque::swap.
  58 }
  59
  60 }  // namespace base