87 lines
2.3 KiB
C++
87 lines
2.3 KiB
C++
/*
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* Copyright 2018-present Facebook, Inc.
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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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#pragma once
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#include <folly/DefaultKeepAliveExecutor.h>
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namespace folly {
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/**
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* VirtualExecutor implements a light-weight view onto existing Executor.
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*
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* Multiple VirtualExecutors can be backed by a single Executor.
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*
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* VirtualExecutor's destructor blocks until all tasks scheduled through it are
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* complete. Executor's destructor also blocks until all VirtualExecutors
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* backed by it are released.
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*/
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class VirtualExecutor : public DefaultKeepAliveExecutor {
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auto wrapFunc(Func f) {
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class FuncAndKeepAlive {
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public:
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FuncAndKeepAlive(Func&& f, VirtualExecutor* executor)
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: keepAlive_(getKeepAliveToken(executor)), f_(std::move(f)) {}
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void operator()() {
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f_();
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}
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private:
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Executor::KeepAlive<VirtualExecutor> keepAlive_;
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Func f_;
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};
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return FuncAndKeepAlive(std::move(f), this);
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}
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public:
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explicit VirtualExecutor(KeepAlive<> executor)
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: executor_(std::move(executor)) {
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assert(!isKeepAliveDummy(executor_));
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}
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explicit VirtualExecutor(Executor* executor)
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: VirtualExecutor(getKeepAliveToken(executor)) {}
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explicit VirtualExecutor(Executor& executor)
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: VirtualExecutor(getKeepAliveToken(executor)) {}
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VirtualExecutor(const VirtualExecutor&) = delete;
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VirtualExecutor& operator=(const VirtualExecutor&) = delete;
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uint8_t getNumPriorities() const override {
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return executor_->getNumPriorities();
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}
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void add(Func f) override {
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executor_->add(wrapFunc(std::move(f)));
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}
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void addWithPriority(Func f, int8_t priority) override {
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executor_->addWithPriority(wrapFunc(std::move(f)), priority);
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}
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~VirtualExecutor() override {
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joinKeepAlive();
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}
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private:
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const KeepAlive<> executor_;
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};
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} // namespace folly
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