blob: 318acad5c6b9ee2457a32236c2f4028fbe5d342b [file] [log] [blame]
// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "extensions/common/one_shot_event.h"
#include "base/callback.h"
#include "base/location.h"
#include "base/message_loop/message_loop_proxy.h"
#include "base/task_runner.h"
using base::TaskRunner;
namespace extensions {
struct OneShotEvent::TaskInfo {
TaskInfo() {}
TaskInfo(const tracked_objects::Location& from_here,
const scoped_refptr<TaskRunner>& runner,
const base::Closure& task)
: from_here(from_here), runner(runner), task(task) {
CHECK(runner.get()); // Detect mistakes with a decent stack frame.
tracked_objects::Location from_here;
scoped_refptr<TaskRunner> runner;
base::Closure task;
OneShotEvent::OneShotEvent() : signaled_(false) {
// It's acceptable to construct the OneShotEvent on one thread, but
// immediately move it to another thread.
OneShotEvent::~OneShotEvent() {}
void OneShotEvent::Post(const tracked_objects::Location& from_here,
const base::Closure& task) const {
Post(from_here, task, base::MessageLoopProxy::current());
void OneShotEvent::Post(const tracked_objects::Location& from_here,
const base::Closure& task,
const scoped_refptr<TaskRunner>& runner) const {
if (is_signaled()) {
runner->PostTask(from_here, task);
} else {
tasks_.push_back(TaskInfo(from_here, runner, task));
void OneShotEvent::Signal() {
CHECK(!signaled_) << "Only call Signal once.";
signaled_ = true;
// After this point, a call to Post() from one of the queued tasks
// could proceed immediately, but the fact that this object is
// single-threaded prevents that from being relevant.
// We could randomize tasks_ in debug mode in order to check that
// the order doesn't matter...
for (size_t i = 0; i < tasks_.size(); ++i) {
tasks_[i].runner->PostTask(tasks_[i].from_here, tasks_[i].task);
} // namespace extensions