spdlog/include/c11log/details/blocking_queue.h
2014-02-09 01:56:21 +02:00

116 lines
3.2 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_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_(),
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), one_hour));
}
// 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, one_hour));
}
// Clear the queue
void clear() {
{
std::unique_lock<std::mutex> ul(mutex_);
queue_t().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_;
const std::chrono::hours one_hour {
1
};
};
}
}