spdlog/include/c11log/details/blocking_queue.h

127 lines
3.6 KiB
C++

#pragma once
// blocking_queue:
// A blocking multi-consumer/multi-producer thread safe queue.
// Has max capacity and supports timeout on push or pop operations.
#include <chrono>
#include <memory>
#include <queue>
#include <mutex>
#include <condition_variable>
namespace c11log
{
namespace details
{
template<typename T>
class blocking_queue
{
public:
using queue_type = std::queue<T>;
using item_type = T;
using size_type = typename queue_type::size_type;
using clock = std::chrono::system_clock;
explicit blocking_queue(size_type max_size) :
_max_size(max_size),
_q(),
_mutex()
{
}
blocking_queue(const blocking_queue&) = delete;
blocking_queue& operator=(const blocking_queue&) = delete;
~blocking_queue() = default;
size_type size()
{
std::lock_guard<std::mutex> lock(_mutex);
return _q.size();
}
// Push copy of item into the back of the queue.
// If the queue is full, block the calling thread util there is room or timeout have passed.
// Return: false on timeout, true on successful push.
template<typename Duration_Rep, typename Duration_Period, typename TT>
bool push(TT&& item, const std::chrono::duration<Duration_Rep, Duration_Period>& timeout)
{
std::unique_lock<std::mutex> ul(_mutex);
if (_q.size() >= _max_size)
{
if (!_item_popped_cond.wait_until(ul, clock::now() + timeout, [this]()
{
return this->_q.size() < this->_max_size;
}))
return false;
}
_q.push(std::forward<TT>(item));
if (_q.size() <= 1)
{
ul.unlock(); //So the notified thread will have better chance to accuire the lock immediatly..
_item_pushed_cond.notify_one();
}
return true;
}
// Push copy of item into the back of the queue.
// If the queue is full, block the calling thread until there is room.
template<typename TT>
void push(TT&& item)
{
while (!push(std::forward<TT>(item), std::chrono::hours(1)));
}
// Pop a copy of the front item in the queue into the given item ref.
// If the queue is empty, block the calling thread util there is item to pop or timeout have passed.
// Return: false on timeout , true on successful pop/
template<class Duration_Rep, class Duration_Period>
bool pop(T& item, const std::chrono::duration<Duration_Rep, Duration_Period>& timeout)
{
std::unique_lock<std::mutex> ul(_mutex);
if (_q.empty())
{
if (!_item_pushed_cond.wait_until(ul, clock::now() + timeout, [this]()
{
return !this->_q.empty();
}))
return false;
}
item = std::move(_q.front());
_q.pop();
if (_q.size() >= _max_size - 1)
{
ul.unlock(); //So the notified thread will have better chance to accuire the lock immediatly..
_item_popped_cond.notify_one();
}
return true;
}
// Pop a copy of the front item in the queue into the given item ref.
// If the queue is empty, block the calling thread util there is item to pop.
void pop(T& item)
{
while (!pop(item, std::chrono::hours(1)));
}
// Clear the queue
void clear()
{
{
std::unique_lock<std::mutex> ul(_mutex);
queue_type().swap(_q);
}
_item_popped_cond.notify_all();
}
private:
size_type _max_size;
std::queue<T> _q;
std::mutex _mutex;
std::condition_variable _item_pushed_cond;
std::condition_variable _item_popped_cond;
};
}
}