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