simple_thread_safe_queue.h
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00001 // Copyright (c) 2017, The Regents of the University of California
00002 // All rights reserved.
00003 //
00004 // Redistribution and use in source and binary forms, with or without
00005 // modification, are permitted provided that the following conditions are met:
00006 // * Redistributions of source code must retain the above copyright
00007 //   notice, this list of conditions and the following disclaimer.
00008 // * Redistributions in binary form must reproduce the above copyright
00009 //   notice, this list of conditions and the following disclaimer in the
00010 //   documentation and/or other materials provided with the distribution.
00011 // * Neither the name of the University of California nor the
00012 //   names of its contributors may be used to endorse or promote products
00013 //   derived from this software without specific prior written permission.
00014 //
00015 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
00016 // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
00017 // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
00018 // ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
00019 // BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
00020 // CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
00021 // SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
00022 // INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
00023 // CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
00024 // ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
00025 // POSSIBILITY OF SUCH DAMAGE.
00026 
00027 #ifndef UTIL_SIMPLE_THREAD_SAFE_QUEUE_H_
00028 #define UTIL_SIMPLE_THREAD_SAFE_QUEUE_H_
00029 
00030 #include <condition_variable>
00031 #include <chrono>
00032 #include <mutex>
00033 #include <queue>
00034 #include <utility>
00035 
00036 #include "util/statusor.h"
00037 
00038 namespace util {
00039 
00040 template <typename T> class SimpleThreadSafeQueue {
00041  private:
00042   std::queue<T> queue_;
00043   std::mutex mutex_;
00044   std::condition_variable condvar_;
00045 
00046  public:
00047   typedef T value_type;
00048   template<typename... Args> void push(Args&&... args) {
00049     std::unique_lock<std::mutex> lock(mutex_);
00050     queue_.push(std::forward<Args>(args)...);
00051     lock.unlock();
00052     condvar_.notify_one();
00053   }
00054 
00055   size_t size() {
00056     std::lock_guard<std::mutex> lock(mutex_);
00057     return queue_.size();
00058   }
00059 
00060   T blocking_pop() {
00061     std::unique_lock<std::mutex> lock(mutex_);
00062     condvar_.wait(lock, [&] { return !queue_.empty(); });
00063     T result = std::move(queue_.front());
00064     queue_.pop();
00065     return std::move(result);
00066   }
00067 
00068   util::StatusOr<T> blocking_pop(int wait_ms) {
00069     std::unique_lock<std::mutex> lock(mutex_);
00070     std::chrono::milliseconds wait_for_duration(wait_ms);
00071     condvar_.wait_for(lock, wait_for_duration, [&] { return !queue_.empty(); });
00072     if (queue_.size() > 0) {
00073       T result = std::move(queue_.front());
00074       queue_.pop();
00075       return std::move(result);
00076     }
00077     return util::Status(util::error::UNAVAILABLE, "Size of the queue is 0.");
00078   }
00079 
00080   util::StatusOr<T> pop() {
00081     std::lock_guard<std::mutex> lock(mutex_);
00082     if (queue_.size() > 0) {
00083       T result = std::move(queue_.front());
00084       queue_.pop();
00085       return std::move(result);
00086     }
00087     return util::Status(util::error::UNAVAILABLE, "Size of the queue is 0.");
00088   }
00089 
00090   void clear() {
00091     std::lock_guard<std::mutex> lock(mutex_);
00092     std::queue<T> tmp;
00093     queue_.swap(tmp);
00094   }
00095 };
00096 
00097 }  // namespace util
00098 
00099 #endif  // UTIL_SIMPLE_THREAD_SAFE_QUEUE_H_


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autogenerated on Thu Jun 6 2019 17:58:03