ConcurrentQueue.h

Go to the documentation of this file.

/*
 *    Copyright (C) 2016-2026 Grok Image Compression Inc.
 *
 *    This source code is free software: you can redistribute it and/or  modify
 *    it under the terms of the GNU Affero General Public License, version 3,
 *    as published by the Free Software Foundation.
 *
 *    This source code is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU Affero General Public License for more details.
 *
 *    You should have received a copy of the GNU Affero General Public License
 *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */
 
#pragma once
 
#include <mutex>
#include <condition_variable>
#include <queue>
 
namespace grk
{

template<typename T>
class ConcurrentQueue
{
public:
  ConcurrentQueue() = default;
 
  void push(T item)
  {
    {
      std::lock_guard<std::mutex> lock(mutex_);
      queue_.push(std::move(item));
    }
    cv_.notify_one();
  }
 
  bool pop(T& item)
  {
    std::unique_lock<std::mutex> lock(mutex_);
    cv_.wait(lock, [this] { return !queue_.empty() || closed_; });
    if(queue_.empty())
      return false;
    item = std::move(queue_.front());
    queue_.pop();
    return true;
  }
 
  void close()
  {
    {
      std::lock_guard<std::mutex> lock(mutex_);
      closed_ = true;
    }
    cv_.notify_all();
  }
 
  size_t size() const
  {
    std::lock_guard<std::mutex> lock(mutex_);
    return queue_.size();
  }
 
private:
  std::queue<T> queue_;
  bool closed_ = false;
  mutable std::mutex mutex_;
  std::condition_variable cv_;
};
 
} // namespace grk