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#pragma once
//
// Copyright(c) 2018 Gabi Melman.
// Distributed under the MIT License (http://opensource.org/licenses/MIT)
//
// async log helper :
// multi producer-multi consumer blocking queue
// enqueue(..) - will block until room found to put the new message
// enqueue_nowait(..) - will return immediatly with false if no room left in the queue
// dequeue_for(..) - will block until the queue is not empty or timeout passed
#include <condition_variable>
#include <mutex>
#include <queue>
namespace spdlog {
namespace details {
template<typename T>
class mpmc_bounded_queue
{
public:
using item_type = T;
explicit mpmc_bounded_queue(size_t max_items)
: max_items_(max_items)
{
}
// try to enqueue and block if no room left
void enqueue(T &&item)
{
{
std::unique_lock<std::mutex> lock(queue_mutex_);
pop_cv_.wait(lock, [this] { return this->q_.size() < this->max_items_; });
q_.push(std::move(item));
}
push_cv_.notify_one();
}
// try to enqueue and return immdeialty false if no room left
bool enqueue_nowait(T &&item)
{
{
std::unique_lock<std::mutex> lock(queue_mutex_);
if (q_.size() == this->max_items_)
{
return false;
}
q_.push(std::forward<T>(item));
}
push_cv_.notify_one();
return true;
}
// try to dequeue item. if no item found. wait upto timeout and try again
// Return true, if succeeded dequeue item, false otherwise
bool dequeue_for(T &popped_item, std::chrono::milliseconds wait_duration)
{
{
std::unique_lock<std::mutex> lock(queue_mutex_);
if (!push_cv_.wait_for(lock, wait_duration, [this] { return this->q_.size() > 0; }))
{
return false;
}
popped_item = std::move(q_.front());
q_.pop();
}
pop_cv_.notify_one();
return true;
}
private:
size_t max_items_;
std::mutex queue_mutex_;
std::condition_variable push_cv_;
std::condition_variable pop_cv_;
std::queue<T> q_;
};
} // namespace details
} // namespace spdlog
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