naiveproxy/base/task_scheduler/delayed_task_manager.cc
2018-08-11 05:35:24 +00:00

96 lines
3.0 KiB
C++

// Copyright 2016 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 "base/task_scheduler/delayed_task_manager.h"
#include <algorithm>
#include "base/bind.h"
#include "base/logging.h"
#include "base/task_runner.h"
#include "base/task_scheduler/task.h"
namespace base {
namespace internal {
DelayedTaskManager::DelayedTaskManager(
std::unique_ptr<const TickClock> tick_clock)
: tick_clock_(std::move(tick_clock)) {
DCHECK(tick_clock_);
}
DelayedTaskManager::~DelayedTaskManager() = default;
void DelayedTaskManager::Start(
scoped_refptr<TaskRunner> service_thread_task_runner) {
DCHECK(service_thread_task_runner);
decltype(tasks_added_before_start_) tasks_added_before_start;
{
AutoSchedulerLock auto_lock(lock_);
DCHECK(!service_thread_task_runner_);
DCHECK(!started_.IsSet());
service_thread_task_runner_ = std::move(service_thread_task_runner);
tasks_added_before_start = std::move(tasks_added_before_start_);
// |service_thread_task_runner_| must not change after |started_| is set
// (cf. comment above |lock_| in header file).
started_.Set();
}
const TimeTicks now = tick_clock_->NowTicks();
for (auto& task_and_callback : tasks_added_before_start) {
const TimeDelta delay =
std::max(TimeDelta(), task_and_callback.first.delayed_run_time - now);
AddDelayedTaskNow(std::move(task_and_callback.first), delay,
std::move(task_and_callback.second));
}
}
void DelayedTaskManager::AddDelayedTask(
Task task,
PostTaskNowCallback post_task_now_callback) {
DCHECK(task.task);
const TimeDelta delay = task.delay;
DCHECK(!delay.is_zero());
// Use CHECK instead of DCHECK to crash earlier. See http://crbug.com/711167
// for details.
CHECK(task.task);
// If |started_| is set, the DelayedTaskManager is in a stable state and
// AddDelayedTaskNow() can be called without synchronization. Otherwise, it is
// necessary to acquire |lock_| and recheck.
if (started_.IsSet()) {
AddDelayedTaskNow(std::move(task), delay,
std::move(post_task_now_callback));
} else {
AutoSchedulerLock auto_lock(lock_);
if (started_.IsSet()) {
AddDelayedTaskNow(std::move(task), delay,
std::move(post_task_now_callback));
} else {
tasks_added_before_start_.push_back(
{std::move(task), std::move(post_task_now_callback)});
}
}
}
void DelayedTaskManager::AddDelayedTaskNow(
Task task,
TimeDelta delay,
PostTaskNowCallback post_task_now_callback) {
DCHECK(task.task);
DCHECK(started_.IsSet());
// TODO(fdoray): Use |task->delayed_run_time| on the service thread
// MessageLoop rather than recomputing it from |delay|.
service_thread_task_runner_->PostDelayedTask(
FROM_HERE, BindOnce(std::move(post_task_now_callback), std::move(task)),
delay);
}
} // namespace internal
} // namespace base