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// Copyright (c) 2010 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 "chrome/common/worker_thread_ticker.h"
#include <algorithm>
#include "base/logging.h"
#include "base/message_loop.h"
#include "base/task.h"
#include "base/threading/thread.h"
class WorkerThreadTicker::TimerTask : public Task {
public:
explicit TimerTask(WorkerThreadTicker* ticker) : ticker_(ticker) {
}
virtual void Run() {
// When the ticker is running, the handler list CANNOT be modified.
// So we can do the enumeration safely without a lock
TickHandlerListType* handlers = &ticker_->tick_handler_list_;
for (TickHandlerListType::const_iterator i = handlers->begin();
i != handlers->end(); ++i) {
(*i)->OnTick();
}
ticker_->ScheduleTimerTask();
}
private:
WorkerThreadTicker* ticker_;
};
WorkerThreadTicker::WorkerThreadTicker(int tick_interval)
: timer_thread_("worker_thread_ticker"),
is_running_(false),
tick_interval_(tick_interval) {
}
WorkerThreadTicker::~WorkerThreadTicker() {
Stop();
}
bool WorkerThreadTicker::RegisterTickHandler(Callback *tick_handler) {
DCHECK(tick_handler);
AutoLock lock(lock_);
// You cannot change the list of handlers when the timer is running.
// You need to call Stop first.
if (IsRunning())
return false;
tick_handler_list_.push_back(tick_handler);
return true;
}
bool WorkerThreadTicker::UnregisterTickHandler(Callback *tick_handler) {
DCHECK(tick_handler);
AutoLock lock(lock_);
// You cannot change the list of handlers when the timer is running.
// You need to call Stop first.
if (IsRunning()) {
return false;
}
TickHandlerListType::iterator index = std::remove(tick_handler_list_.begin(),
tick_handler_list_.end(),
tick_handler);
if (index == tick_handler_list_.end()) {
return false;
}
tick_handler_list_.erase(index, tick_handler_list_.end());
return true;
}
bool WorkerThreadTicker::Start() {
// Do this in a lock because we don't want 2 threads to
// call Start at the same time
AutoLock lock(lock_);
if (IsRunning())
return false;
if (!timer_thread_.Start())
return false;
is_running_ = true;
ScheduleTimerTask();
return true;
}
bool WorkerThreadTicker::Stop() {
// Do this in a lock because we don't want 2 threads to
// call Stop at the same time
AutoLock lock(lock_);
if (!IsRunning())
return false;
is_running_ = false;
timer_thread_.Stop();
return true;
}
void WorkerThreadTicker::ScheduleTimerTask() {
timer_thread_.message_loop()->PostDelayedTask(FROM_HERE, new TimerTask(this),
tick_interval_);
}
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