spdlog/include/c11log/details/blocking_queue.h
gabi df56bb775a 1. Added test
2. Fixes
2014-01-25 15:52:10 +02:00

108 lines
3.5 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 <cstddef>
#include <chrono>
#include <memory>
#include <queue>
#include <mutex>
#include <condition_variable>
namespace c11log {
namespace details
{
template<typename T>
class blocking_queue {
public:
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() = 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<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_until(ul, clock::now() + timeout, [this]() { return this->q_.size() < this->max_size_; }))
return false;
}
q_.push(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.
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 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 = 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::max()));
}
// Clear the queue
void clear()
{
T item;
while (pop(item, std::chrono::milliseconds(0)));
}
private:
size_type max_size_;
std::queue<T> q_;
std::mutex mutex_;
std::condition_variable item_pushed_cond_;
std::condition_variable item_popped_cond_;
};
}
}