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- /*
- * Copyright 2014-present Facebook, Inc.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
- #include <folly/io/async/EventBaseManager.h>
- namespace folly {
- std::atomic<EventBaseManager*> globalManager(nullptr);
- EventBaseManager* EventBaseManager::get() {
- EventBaseManager* mgr = globalManager;
- if (mgr) {
- return mgr;
- }
- EventBaseManager* new_mgr = new EventBaseManager;
- bool exchanged = globalManager.compare_exchange_strong(mgr, new_mgr);
- if (!exchanged) {
- delete new_mgr;
- return mgr;
- } else {
- return new_mgr;
- }
- }
- /*
- * EventBaseManager methods
- */
- void EventBaseManager::setEventBase(EventBase* eventBase, bool takeOwnership) {
- EventBaseInfo* info = localStore_.get();
- if (info != nullptr) {
- throw std::runtime_error(
- "EventBaseManager: cannot set a new EventBase "
- "for this thread when one already exists");
- }
- info = new EventBaseInfo(eventBase, takeOwnership);
- localStore_.reset(info);
- this->trackEventBase(eventBase);
- }
- void EventBaseManager::clearEventBase() {
- EventBaseInfo* info = localStore_.get();
- if (info != nullptr) {
- this->untrackEventBase(info->eventBase);
- this->localStore_.reset(nullptr);
- }
- }
- // XXX should this really be "const"?
- EventBase* EventBaseManager::getEventBase() const {
- // have one?
- auto* info = localStore_.get();
- if (!info) {
- info = new EventBaseInfo();
- localStore_.reset(info);
- if (observer_) {
- info->eventBase->setObserver(observer_);
- }
- // start tracking the event base
- // XXX
- // note: ugly cast because this does something mutable
- // even though this method is defined as "const".
- // Simply removing the const causes trouble all over fbcode;
- // lots of services build a const EventBaseManager and errors
- // abound when we make this non-const.
- (const_cast<EventBaseManager*>(this))->trackEventBase(info->eventBase);
- }
- return info->eventBase;
- }
- } // namespace folly
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