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/Synchronized.h>
21 #include <folly/executors/task_queue/BlockingQueue.h>
26 // Warning: this is effectively just a std::deque wrapped in a single mutex
27 // We are aiming to add a more performant concurrent unbounded queue in the
28 // future, but this class is available if you must have an unbounded queue
29 // and can tolerate any contention.
31 class UnboundedBlockingQueue : public BlockingQueue<T> {
33 virtual ~UnboundedBlockingQueue() {}
35 void add(T item) override {
36 queue_.wlock()->push(std::move(item));
43 auto ulockedQueue = queue_.ulock();
44 if (!ulockedQueue->empty()) {
45 auto wlockedQueue = ulockedQueue.moveFromUpgradeToWrite();
46 T item = std::move(wlockedQueue->front());
55 size_t size() override {
56 return queue_.rlock()->size();
61 Synchronized<std::queue<T>> queue_;