| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| #ifndef LIB_UNBOUNDEDBLOCKINGQUEUE_H_ |
| #define LIB_UNBOUNDEDBLOCKINGQUEUE_H_ |
| |
| #include <mutex> |
| #include <condition_variable> |
| #include <boost/circular_buffer.hpp> |
| // For struct QueueNotEmpty |
| #include "BlockingQueue.h" |
| |
| template <typename T> |
| class UnboundedBlockingQueue { |
| public: |
| typedef typename boost::circular_buffer<T> Container; |
| typedef typename Container::iterator iterator; |
| typedef typename Container::const_iterator const_iterator; |
| |
| UnboundedBlockingQueue(size_t maxSize) : mutex_(), queue_(maxSize) {} |
| |
| ~UnboundedBlockingQueue() { |
| Lock lock(mutex_); |
| queue_.clear(); |
| } |
| |
| void push(const T& value) { |
| Lock lock(mutex_); |
| // If the queue is full, wait for space to be available |
| bool wasEmpty = queue_.empty(); |
| if (queue_.full()) { |
| queue_.set_capacity(queue_.size() * 2); |
| } |
| queue_.push_back(value); |
| lock.unlock(); |
| |
| if (wasEmpty) { |
| // Notify that an element is pushed |
| queueEmptyCondition_.notify_one(); |
| } |
| } |
| |
| void pop() { |
| Lock lock(mutex_); |
| // If the queue is empty, wait until an element is available to be popped |
| queueEmptyCondition_.wait(lock, QueueNotEmpty<UnboundedBlockingQueue<T> >(*this)); |
| queue_.pop_front(); |
| lock.unlock(); |
| } |
| |
| void pop(T& value) { |
| Lock lock(mutex_); |
| // If the queue is empty, wait until an element is available to be popped |
| queueEmptyCondition_.wait(lock, QueueNotEmpty<UnboundedBlockingQueue<T> >(*this)); |
| value = queue_.front(); |
| queue_.pop_front(); |
| lock.unlock(); |
| } |
| |
| template <typename Duration> |
| bool pop(T& value, const Duration& timeout) { |
| Lock lock(mutex_); |
| if (!queueEmptyCondition_.wait_for(lock, timeout, QueueNotEmpty<UnboundedBlockingQueue<T> >(*this))) { |
| return false; |
| } |
| |
| value = queue_.front(); |
| queue_.pop_front(); |
| lock.unlock(); |
| |
| return true; |
| } |
| |
| // Check the 1st element of the queue |
| bool peek(T& value) { |
| Lock lock(mutex_); |
| if (queue_.empty()) { |
| return false; |
| } |
| |
| value = queue_.front(); |
| return true; |
| } |
| |
| // Remove all elements from the queue |
| void clear() { |
| Lock lock(mutex_); |
| queue_.clear(); |
| } |
| |
| // Check 1st item and clear the queue atomically |
| bool peekAndClear(T& value) { |
| Lock lock(mutex_); |
| if (queue_.empty()) { |
| return false; |
| } |
| |
| value = queue_.front(); |
| queue_.clear(); |
| return true; |
| } |
| |
| size_t size() const { |
| Lock lock(mutex_); |
| return queue_.size(); |
| } |
| |
| bool empty() const { |
| Lock lock(mutex_); |
| return isEmptyNoMutex(); |
| } |
| |
| const_iterator begin() const { return queue_.begin(); } |
| |
| const_iterator end() const { return queue_.end(); } |
| |
| iterator begin() { return queue_.begin(); } |
| |
| iterator end() { return queue_.end(); } |
| |
| private: |
| bool isEmptyNoMutex() const { return queue_.empty(); } |
| |
| mutable std::mutex mutex_; |
| std::condition_variable queueEmptyCondition_; |
| Container queue_; |
| |
| typedef std::unique_lock<std::mutex> Lock; |
| friend struct QueueNotEmpty<UnboundedBlockingQueue<T> >; |
| }; |
| |
| #endif /* LIB_BLOCKINGQUEUE_H_ */ |