base/mac/libdispatch_task_runner.cc

   1 // Copyright (c) 2012 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/mac/libdispatch_task_runner.h"
   6
   7 #include "base/callback.h"
   8
   9 namespace base {
  10 namespace mac {
  11
  12 LibDispatchTaskRunner::LibDispatchTaskRunner(const char* name)
  13     : queue_(dispatch_queue_create(name, NULL)),
  14       queue_finalized_(false, false) {
  15   dispatch_set_context(queue_, this);
  16   dispatch_set_finalizer_f(queue_, &LibDispatchTaskRunner::Finalizer);
  17 }
  18
  19 bool LibDispatchTaskRunner::PostDelayedTask(
  20     const tracked_objects::Location& from_here,
  21     const Closure& task,
  22     base::TimeDelta delay) {
  23   if (!queue_)
  24     return false;
  25
  26   // The block runtime would implicitly copy the reference, not the object
  27   // it's referencing. Copy the closure into block storage so it's available
  28   // to run.
  29   __block const Closure task_copy = task;
  30   void(^run_task)(void) = ^{
  31       task_copy.Run();
  32   };
  33
  34   int64 delay_nano =
  35       delay.InMicroseconds() * base::Time::kNanosecondsPerMicrosecond;
  36   if (delay_nano > 0) {
  37     dispatch_time_t time = dispatch_time(DISPATCH_TIME_NOW, delay_nano);
  38     dispatch_after(time, queue_, run_task);
  39   } else {
  40     dispatch_async(queue_, run_task);
  41   }
  42   return true;
  43 }
  44
  45 bool LibDispatchTaskRunner::RunsTasksOnCurrentThread() const {
  46   return queue_ == dispatch_get_current_queue();
  47 }
  48
  49 bool LibDispatchTaskRunner::PostNonNestableDelayedTask(
  50     const tracked_objects::Location& from_here,
  51     const Closure& task,
  52     base::TimeDelta delay) {
  53   return PostDelayedTask(from_here, task, delay);
  54 }
  55
  56 void LibDispatchTaskRunner::Shutdown() {
  57   dispatch_release(queue_);
  58   queue_ = NULL;
  59   queue_finalized_.Wait();
  60 }
  61
  62 dispatch_queue_t LibDispatchTaskRunner::GetDispatchQueue() const {
  63   return queue_;
  64 }
  65
  66 LibDispatchTaskRunner::~LibDispatchTaskRunner() {
  67   if (queue_) {
  68     dispatch_set_context(queue_, NULL);
  69     dispatch_set_finalizer_f(queue_, NULL);
  70     dispatch_release(queue_);
  71   }
  72 }
  73
  74 void LibDispatchTaskRunner::Finalizer(void* context) {
  75   LibDispatchTaskRunner* self = static_cast<LibDispatchTaskRunner*>(context);
  76   self->queue_finalized_.Signal();
  77 }
  78
  79 }  // namespace mac
  80 }  // namespace base