C++11 library providing functionality common to all adapters.
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// This file is under GNU General Public License 3.0
// see LICENSE.txt
#pragma once
#include <list>
#include <condition_variable>
#include <mutex>
namespace utility
{
template<class T, void(*Deleter)(T) = nullptr>
class locked_queue
{
typedef std::recursive_mutex Mutex;
typedef std::unique_lock<Mutex> Lock;
Mutex _mtx;
std::condition_variable_any _cv;
std::list<T> _q;
public:
~locked_queue()
{
clear();
}
void clear()
{
Lock L(_mtx);
if(Deleter != nullptr)
{
for(auto q : _q)
{
Deleter(q);
}
}
_q.clear();
}
// undefined behavior when queue empty
T& back()
{
Lock lg(_mtx);
return _q.back();
}
// undefined behavior when queue empty
T& front()
{
Lock lg(_mtx);
return _q.front();
}
// returns a copy of the last element.
// blocks when queue is empty
T pop_back()
{
Lock L(_mtx);
_cv.wait(L, [&]{ return !_q.empty(); } );
T r{std::move(_q.back())};
_q.pop_back();
return r;
}
// returns a copy of the first element.
// blocks when queue is empty
T pop_front()
{
Lock L(_mtx);
_cv.wait(L, [&]{ return !_q.empty(); } );
T r{std::move(_q.front())};
_q.pop_front();
return r;
}
// returns true and set a copy of the last element and pop it from queue if there is any
// returns false and leaves 'out' untouched if queue is empty even after 'end_time'
bool try_pop_back(T& out, std::chrono::steady_clock::time_point end_time)
{
Lock L(_mtx);
if(! _cv.wait_until(L, end_time, [this]{ return !_q.empty(); } ) )
{
return false;
}
out = std::move(_q.back());
_q.pop_back();
return true;
}
// returns true and set a copy of the first element and pop it from queue if there is any
// returns false and leaves 'out' untouched if queue is empty even after 'end_time'
bool try_pop_front(T& out, std::chrono::steady_clock::time_point end_time)
{
Lock L(_mtx);
if(! _cv.wait_until(L, end_time, [this]{ return !_q.empty(); } ) )
{
return false;
}
out = std::move(_q.front());
_q.pop_front();
return true;
}
// returns true and set a copy of the first element and pop it from queue if there is any
// returns false and leaves 'out' untouched if queue is empty even after 'duration'
bool try_pop_front(T& out, std::chrono::seconds duration)
{
Lock L(_mtx);
if(! _cv.wait_for(L, duration, [this]{ return !_q.empty(); } ) )
{
return false;
}
out = std::move(_q.front());
_q.pop_front();
return true;
}
void push_back(const T& data)
{
{
Lock L(_mtx);
_q.push_back(data);
}
_cv.notify_one();
}
void emplace_back(const T& data)
{
{
Lock L(_mtx);
_q.emplace_back(data);
}
_cv.notify_one();
}
void push_front(const T& data)
{
{
Lock L(_mtx);
_q.push_front(data);
}
_cv.notify_one();
}
size_t size()
{
Lock lg(_mtx);
return _q.size();
}
bool empty()
{
Lock lg(_mtx);
return _q.empty();
}
};
}