blocking_queue

This commit is contained in:
gabi 2014-01-25 12:50:26 +02:00
parent 681e40ce46
commit 60c3bb3c41

View File

@ -1,5 +1,9 @@
#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 <cstddef>
#include <chrono>
#include <memory>
@ -8,57 +12,91 @@
#include <condition_variable>
namespace c11log {
namespace details {
namespace details
{
template<typename T>
class blocking_queue {
public:
explicit blocking_queue(std::size_t max_size) :_max_size(max_size), _q()
using queue_t = std::queue<T>;
using size_type = typename queue_t::size_type;
using clock = std::chrono::system_clock;
explicit blocking_queue(size_type max_size) :_max_size(max_size), _q()
{}
blocking_queue(const blocking_queue&) = delete;
blocking_queue& operator=(const blocking_queue&) = delete;
blocking_queue& operator=(const blocking_queue&) volatile = delete;
~blocking_queue() = default;
std::size_t size()
size_type size()
{
std::lock_guard<std::mutex> lock(_mutex);
return _q.size();
}
bool push(const T& item, const std::chrono::milliseconds& timeout)
// Push copy of item into the back of the queue.
// If queue is full, block the calling thread util there is room or timeout have passed.
// Return: false on timeout, true on successful push.
template<class Duration_Rep, class Duration_Period>
bool push(const T& 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_for(ul, timeout) == std::cv_status::timeout || _q.size() >= _max_size)
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(item);
if (_q.size() <= 1)
_item_pushed_cond.notify_all();
if (_q.size() == 1)
{
ul.unlock();
_item_pushed_cond.notify_one();
}
return true;
}
bool pop(T& item, const std::chrono::milliseconds& timeout)
// Push copy of item into the back of the queue.
// If queue is full, block the calling thread until there is room
void push(const T& item)
{
while (!push(item, std::chrono::hours::max()));
}
// Pop a copy of the front item in the queue into the given item ref
// If 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_for(ul, timeout) == std::cv_status::timeout || _q.empty())
if (_q.empty())
{
if (!_item_pushed_cond.wait_until(ul, clock::now() + timeout, [this]() { return !this->_q.empty(); }))
return false;
}
item = _q.front();
_q.pop();
if (_q.size() >= _max_size - 1)
_item_popped_cond.notify_all();
{
ul.unlock();
_item_popped_cond.notify_one();
}
return true;
}
// Pop a copy of the front item in the queue into the given item ref
// If queue is empty, block the calling thread util there is item to pop.
void pop(T& item)
{
while (!pop(item, std::chrono::hours::max()));
}
private:
std::size_t _max_size;
size_type _max_size;
std::queue<T> _q;
std::mutex _mutex;
std::condition_variable _item_pushed_cond;
std::condition_variable _item_popped_cond;
};
}
}