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// Copyright (c) 2006-2008 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 <algorithm>
#include "base/logging.h"
#include "chrome/common/worker_thread_ticker.h"
WorkerThreadTicker::WorkerThreadTicker(int tick_interval)
: tick_interval_(tick_interval),
wait_handle_(NULL) {
}
WorkerThreadTicker::~WorkerThreadTicker() {
Stop();
}
bool WorkerThreadTicker::RegisterTickHandler(Callback *tick_handler) {
DCHECK(tick_handler);
AutoLock lock(tick_handler_list_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(tick_handler_list_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(tick_handler_list_lock_);
if (IsRunning()) {
return false;
}
bool ret = false;
HANDLE event = CreateEvent(NULL, FALSE, FALSE, NULL);
if (!event) {
NOTREACHED();
} else {
if (!RegisterWaitForSingleObject(
&wait_handle_,
event,
reinterpret_cast<WAITORTIMERCALLBACK>(TickCallback),
this,
tick_interval_,
WT_EXECUTEDEFAULT)) {
NOTREACHED();
CloseHandle(event);
} else {
dummy_event_.Attach(event);
ret = true;
}
}
return ret;
}
bool WorkerThreadTicker::Stop() {
// Do this in a lock because we don't want 2 threads to
// call Stop at the same time
AutoLock lock(tick_handler_list_lock_);
if (!IsRunning()) {
return false;
}
DCHECK(wait_handle_);
// Wait for the callbacks to be done. Passing
// INVALID_HANDLE_VALUE to UnregisterWaitEx achieves this.
UnregisterWaitEx(wait_handle_, INVALID_HANDLE_VALUE);
wait_handle_ = NULL;
dummy_event_.Close();
return true;
}
bool WorkerThreadTicker::IsRunning() const {
return (wait_handle_ != NULL);
}
void WorkerThreadTicker::InvokeHandlers() {
// When the ticker is running, the handler list CANNOT be modified.
// So we can do the enumeration safely without a lock
TickHandlerListType::iterator index = tick_handler_list_.begin();
while (index != tick_handler_list_.end()) {
(*index)->OnTick();
index++;
}
}
void CALLBACK WorkerThreadTicker::TickCallback(WorkerThreadTicker* this_ticker,
BOOLEAN timer_or_wait_fired) {
DCHECK(NULL != this_ticker);
if (NULL != this_ticker) {
this_ticker->InvokeHandlers();
}
}
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