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// Copyright (C) 2016 Davis E. King (davis@dlib.net)
// License: Boost Software License See LICENSE.txt for the full license.
#ifndef DLIB_AsYNC_Hh_
#define DLIB_AsYNC_Hh_
// C++11 things don't work in old versions of visual studio
#if !defined( _MSC_VER) || _MSC_VER >= 1900
#include "async_abstract.h"
#include "thread_pool_extension.h"
#include <future>
#include <functional>
namespace dlib
{
// ----------------------------------------------------------------------------------------
namespace impl
{
template <typename T> struct selector {};
template <typename T, typename U, typename V>
void call_prom_set_value(
T& prom,
U& fun,
selector<V>
)
{
prom.set_value(fun());
}
template <typename T, typename U>
void call_prom_set_value(
T& prom,
U& fun,
selector<void>
)
{
fun();
prom.set_value();
}
template <typename> struct result_of;
#if (__cplusplus >= 201703L || \
(defined(_MSVC_LANG) && _MSVC_LANG >= 201703L)) && \
__cpp_lib_is_invocable >= 201703L
template <typename F, typename... Args>
struct result_of<F(Args...)> : std::invoke_result<F, Args...> {};
#else
template <typename F, typename... Args>
struct result_of<F(Args...)>
: std::result_of<F&&(Args&&...)> {};
#endif
}
// ----------------------------------------------------------------------------------------
thread_pool& default_thread_pool();
// ----------------------------------------------------------------------------------------
template <
typename Function,
typename ...Args
>
std::future<typename impl::result_of<Function(Args...)>::type> async(
thread_pool& tp,
Function&& f,
Args&&... args
)
{
auto prom = std::make_shared<std::promise<typename impl::result_of<Function(Args...)>::type>>();
std::future<typename impl::result_of<Function(Args...)>::type> ret = prom->get_future();
using bind_t = decltype(std::bind(std::forward<Function>(f), std::forward<Args>(args)...));
auto fun = std::make_shared<bind_t>(std::bind(std::forward<Function>(f), std::forward<Args>(args)...));
tp.add_task_by_value([fun, prom]()
{
try
{
impl::call_prom_set_value(*prom, *fun, impl::selector<typename impl::result_of<Function(Args...)>::type>());
}
catch(...)
{
prom->set_exception(std::current_exception());
}
});
return ret;
}
// ----------------------------------------------------------------------------------------
template <
typename Function,
typename ...Args
>
std::future<typename impl::result_of<Function(Args...)>::type> async(
Function&& f,
Args&&... args
)
{
return async(default_thread_pool(), std::forward<Function>(f), std::forward<Args>(args)...);
}
}
// ----------------------------------------------------------------------------------------
#ifdef NO_MAKEFILE
#include "async.cpp"
#endif
#endif
#endif // DLIB_AsYNC_Hh_
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