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construct/include/ircd/ctx/async.h
Jason Volk d9a4f06bf6 ircd: Employ namespace scope extensions from c++1z/gnu++14.
This is not a move to c++17. If the compiler happens to have support
for c++17 namespace scope resolution, they have been kind enough to
backport it to gnu++14. This limits our support for really old c++14
compilers, but that was limited anyway. GCC 6.1 and clang 3.6 tested.
2017-09-08 03:47:46 -07:00

108 lines
3.2 KiB
C++

/*
* Copyright (C) 2016 Charybdis Development Team
* Copyright (C) 2016 Jason Volk <jason@zemos.net>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice is present in all copies.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#define HAVE_IRCD_CTX_ASYNC_H
namespace ircd::ctx
{
template<class F,
class... A>
constexpr bool is_void_result();
template<class F,
class... A>
using future_void = typename std::enable_if<is_void_result<F, A...>(), future<void>>::type;
template<class F,
class... A>
using future_value = typename std::enable_if<!is_void_result<F, A...>(),
future<typename std::result_of<F (A...)>::type>>::type;
template<size_t stack_size = DEFAULT_STACK_SIZE,
context::flags flags = (context::flags)0,
class F,
class... A>
future_value<F, A...> async(F&& f, A&&... a);
template<size_t stack_size = DEFAULT_STACK_SIZE,
context::flags flags = context::flags(0),
class F,
class... A>
future_void<F, A...> async(F&& f, A&&... a);
}
template<size_t stack_size,
ircd::ctx::context::flags flags,
class F,
class... A>
ircd::ctx::future_value<F, A...>
ircd::ctx::async(F&& f,
A&&... a)
{
using R = typename std::result_of<F (A...)>::type;
auto func(std::bind(std::forward<F>(f), std::forward<A>(a)...));
auto p(std::make_shared<promise<R>>());
auto wrapper([p, func(std::move(func))]
() mutable -> void
{
p->set_value(func());
});
future<R> ret(*p);
//TODO: DEFER_POST?
context(stack_size, std::move(wrapper), context::DETACH | context::POST | flags);
return ret;
}
template<size_t stack_size,
ircd::ctx::context::flags flags,
class F,
class... A>
ircd::ctx::future_void<F, A...>
ircd::ctx::async(F&& f,
A&&... a)
{
using R = typename std::result_of<F (A...)>::type;
auto func(std::bind(std::forward<F>(f), std::forward<A>(a)...));
auto p(std::make_shared<promise<R>>());
auto wrapper([p, func(std::move(func))]
() mutable -> void
{
func();
p->set_value();
});
future<R> ret(*p);
//TODO: DEFER_POST?
context(stack_size, std::move(wrapper), context::DETACH | context::POST | flags);
return ret;
}
template<class F,
class... A>
constexpr bool
ircd::ctx::is_void_result()
{
return std::is_void<typename std::result_of<F (A...)>::type>::value;
}