77 lines
2.0 KiB
C++
77 lines
2.0 KiB
C++
/*
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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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#pragma once
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#include <folly/MPMCQueue.h>
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#include <folly/executors/task_queue/BlockingQueue.h>
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#include <folly/synchronization/LifoSem.h>
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namespace folly {
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template <class T, QueueBehaviorIfFull kBehavior = QueueBehaviorIfFull::THROW>
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class LifoSemMPMCQueue : public BlockingQueue<T> {
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public:
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// Note: The queue pre-allocates all memory for max_capacity
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explicit LifoSemMPMCQueue(size_t max_capacity) : queue_(max_capacity) {}
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BlockingQueueAddResult add(T item) override {
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switch (kBehavior) { // static
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case QueueBehaviorIfFull::THROW:
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if (!queue_.writeIfNotFull(std::move(item))) {
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throw QueueFullException("LifoSemMPMCQueue full, can't add item");
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}
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break;
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case QueueBehaviorIfFull::BLOCK:
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queue_.blockingWrite(std::move(item));
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break;
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}
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return sem_.post();
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}
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T take() override {
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T item;
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while (!queue_.readIfNotEmpty(item)) {
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sem_.wait();
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}
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return item;
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}
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folly::Optional<T> try_take_for(std::chrono::milliseconds time) override {
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T item;
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while (!queue_.readIfNotEmpty(item)) {
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if (!sem_.try_wait_for(time)) {
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return folly::none;
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}
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}
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return item;
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}
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size_t capacity() {
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return queue_.capacity();
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}
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size_t size() override {
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return queue_.size();
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}
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private:
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folly::LifoSem sem_;
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folly::MPMCQueue<T> queue_;
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};
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} // namespace folly
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