109 lines
3.4 KiB
C++
109 lines
3.4 KiB
C++
/// \file mingw.invoke.h
|
|
/// \brief Lightweight `invoke` implementation, for C++11 and C++14.
|
|
///
|
|
/// (c) 2018-2019 by Nathaniel J. McClatchey, San Jose, CA, United States
|
|
/// \author Nathaniel J. McClatchey, PhD
|
|
///
|
|
/// \copyright Simplified (2-clause) BSD License.
|
|
///
|
|
/// \note This file may become part of the mingw-w64 runtime package. If/when
|
|
/// this happens, the appropriate license will be added, i.e. this code will
|
|
/// become dual-licensed, and the current BSD 2-clause license will stay.
|
|
|
|
#ifndef MINGW_INVOKE_H_
|
|
#define MINGW_INVOKE_H_
|
|
|
|
#include <type_traits> // For std::result_of, etc.
|
|
#include <utility> // For std::forward
|
|
#include <functional> // For std::reference_wrapper
|
|
|
|
namespace mingw_stdthread
|
|
{
|
|
namespace detail
|
|
{
|
|
// For compatibility, implement std::invoke for C++11 and C++14
|
|
#if __cplusplus < 201703L
|
|
template<bool PMemFunc, bool PMemData>
|
|
struct Invoker
|
|
{
|
|
template<class F, class... Args>
|
|
inline static typename std::result_of<F(Args...)>::type invoke (F&& f, Args&&... args)
|
|
{
|
|
return std::forward<F>(f)(std::forward<Args>(args)...);
|
|
}
|
|
};
|
|
template<bool>
|
|
struct InvokerHelper;
|
|
|
|
template<>
|
|
struct InvokerHelper<false>
|
|
{
|
|
template<class T1>
|
|
inline static auto get (T1&& t1) -> decltype(*std::forward<T1>(t1))
|
|
{
|
|
return *std::forward<T1>(t1);
|
|
}
|
|
|
|
template<class T1>
|
|
inline static auto get (const std::reference_wrapper<T1>& t1) -> decltype(t1.get())
|
|
{
|
|
return t1.get();
|
|
}
|
|
};
|
|
|
|
template<>
|
|
struct InvokerHelper<true>
|
|
{
|
|
template<class T1>
|
|
inline static auto get (T1&& t1) -> decltype(std::forward<T1>(t1))
|
|
{
|
|
return std::forward<T1>(t1);
|
|
}
|
|
};
|
|
|
|
template<>
|
|
struct Invoker<true, false>
|
|
{
|
|
template<class T, class F, class T1, class... Args>
|
|
inline static auto invoke (F T::* f, T1&& t1, Args&&... args) ->\
|
|
decltype((InvokerHelper<std::is_base_of<T,typename std::decay<T1>::type>::value>::get(std::forward<T1>(t1)).*f)(std::forward<Args>(args)...))
|
|
{
|
|
return (InvokerHelper<std::is_base_of<T,typename std::decay<T1>::type>::value>::get(std::forward<T1>(t1)).*f)(std::forward<Args>(args)...);
|
|
}
|
|
};
|
|
|
|
template<>
|
|
struct Invoker<false, true>
|
|
{
|
|
template<class T, class F, class T1, class... Args>
|
|
inline static auto invoke (F T::* f, T1&& t1, Args&&... args) ->\
|
|
decltype(InvokerHelper<std::is_base_of<T,typename std::decay<T1>::type>::value>::get(t1).*f)
|
|
{
|
|
return InvokerHelper<std::is_base_of<T,typename std::decay<T1>::type>::value>::get(t1).*f;
|
|
}
|
|
};
|
|
|
|
template<class F, class... Args>
|
|
struct InvokeResult
|
|
{
|
|
typedef Invoker<std::is_member_function_pointer<typename std::remove_reference<F>::type>::value,
|
|
std::is_member_object_pointer<typename std::remove_reference<F>::type>::value &&
|
|
(sizeof...(Args) == 1)> invoker;
|
|
inline static auto invoke (F&& f, Args&&... args) -> decltype(invoker::invoke(std::forward<F>(f), std::forward<Args>(args)...))
|
|
{
|
|
return invoker::invoke(std::forward<F>(f), std::forward<Args>(args)...);
|
|
}
|
|
};
|
|
|
|
template<class F, class...Args>
|
|
auto invoke (F&& f, Args&&... args) -> decltype(InvokeResult<F, Args...>::invoke(std::forward<F>(f), std::forward<Args>(args)...))
|
|
{
|
|
return InvokeResult<F, Args...>::invoke(std::forward<F>(f), std::forward<Args>(args)...);
|
|
}
|
|
#else
|
|
using std::invoke;
|
|
#endif
|
|
} // Namespace "detail"
|
|
} // Namespace "mingw_stdthread"
|
|
|
|
#endif
|