thread_safe_queue.h

/************
 * 存放yuv数据的全局队列
 * ThreadSafeQueue<shared_ptr<VideoImageParaT>> yuv_image_queue(kImageDataQueueSize);
**************/
#ifndef THREAD_SAFE_QUEUE_H_
#define THREAD_SAFE_QUEUE_H_

#include <mutex>
#include <queue>

template<typename T>
class ThreadSafeQueue {
 public:

  /**
   * @brief ThreadSafeQueue constructor
   * @param [in] capacity: the queue capacity
   */
  ThreadSafeQueue(int capacity) {
    // check the input value: capacity is valid
    if (capacity >= kMinQueueCapacity && capacity <= kMaxQueueCapacity) {
      queue_capacity = capacity;
    } else { // the input value: capacity is invalid, set the default value
      queue_capacity = kDefaultQueueCapacity;
    }
  }

  /**
   * @brief ThreadSafeQueue constructor
   */
  ThreadSafeQueue() {
    queue_capacity = kDefaultQueueCapacity;
  }

  /**
   * @brief ThreadSafeQueue destructor
   */
  ~ThreadSafeQueue() = default;

  /**
   * @brief push data to queue
   * @param [in] input_value: the value will push to the queue
   * @return true: success to push data; false: fail to push data
   */
  bool Push(T input_value) {
    std::lock_guard<std::mutex> lock(mutex_);

    // check current size is less than capacity
    if (queue_.size() < queue_capacity) {
      queue_.push(input_value);
      return true;
    }

    return false;
  }

  /**
   * @brief pop data from queue
   * @return true: success to pop data; false: fail to pop data
   */
  T Pop() {
    std::lock_guard<std::mutex> lock(mutex_);
    if (queue_.empty()) { // check the queue is empty
      return nullptr;
    }

    T tmp_ptr = queue_.front();
    queue_.pop();
    return tmp_ptr;
  }

  /**
   * @brief check the queue is empty
   * @return true: the queue is empty; false: the queue is not empty
   */
  bool empty() {
    std::lock_guard<std::mutex> lock(mutex_);
    return queue_.empty();
  }

  /**
   * @brief get the queue size
   * @return the queue size
   */
  int size() {
    std::lock_guard<std::mutex> lock(mutex_);
    return queue_.size();
  }

 private:
  std::queue<T> queue_; // the queue

  int queue_capacity; // queue capacity

  mutable std::mutex mutex_; // the mutex value

  const int kMinQueueCapacity = 1; // the minimum queue capacity

  const int kMaxQueueCapacity = 10000; // the maximum queue capacity

  const int kDefaultQueueCapacity = 10; // default queue capacity
};

#endif /* THREAD_SAFE_QUEUE_H_ */