2 * Copyright 2017 Facebook, Inc.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
19 #include <folly/LifoSem.h>
20 #include <folly/MPMCQueue.h>
21 #include <folly/executors/BlockingQueue.h>
25 template <class T, QueueBehaviorIfFull kBehavior = QueueBehaviorIfFull::THROW>
26 class LifoSemMPMCQueue : public BlockingQueue<T> {
28 // Note: The queue pre-allocates all memory for max_capacity
29 explicit LifoSemMPMCQueue(size_t max_capacity) : queue_(max_capacity) {}
31 void add(T item) override {
32 switch (kBehavior) { // static
33 case QueueBehaviorIfFull::THROW:
34 if (!queue_.write(std::move(item))) {
35 throw QueueFullException("LifoSemMPMCQueue full, can't add item");
38 case QueueBehaviorIfFull::BLOCK:
39 queue_.blockingWrite(std::move(item));
47 while (!queue_.readIfNotEmpty(item)) {
54 return queue_.capacity();
57 size_t size() override {
63 folly::MPMCQueue<T> queue_;