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construct/include/ircd/util/closure.h

83 lines
2 KiB
C++

// Matrix Construct
//
// Copyright (C) Matrix Construct Developers, Authors & Contributors
// Copyright (C) 2016-2019 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. The
// full license for this software is available in the LICENSE file.
#pragma once
#define HAVE_IRCD_UTIL_CLOSURE_H
namespace ircd {
inline namespace util
{
template<template<class, class...>
class F,
class R,
class... A>
struct closure;
template<template<class, class...>
class F,
class... A>
struct closure<F, bool, A...>;
/// Template for creating callback-based iterations allowing closures of
/// either `void (...)` or `bool (...)` to be passed to the same overload.
///
/// This reduces/deduplicates interfaces which offer an overload for each
/// and thus two library symbols, usually just calling each other...
///
template<template<class, class...>
class F,
class... A>
using closure_bool = closure<F, bool, A...>;
}}
template<template<class, class...>
class F,
class R,
class... A>
struct ircd::util::closure
:F<R (A...)>
{
using proto_type = R (A...);
using func_type = F<proto_type>;
using func_type::func_type;
using func_type::operator=;
};
template<template<class, class...>
class F,
class... A>
struct ircd::util::closure<F, bool, A...>
:F<bool (A...)>
{
using proto_type = bool (A...);
using func_type = F<proto_type>;
template<class lambda>
closure(lambda &&o) noexcept;
};
template<template<class, class...>
class F,
class... A>
template<class lambda>
[[gnu::always_inline]]
inline
ircd::util::closure<F, bool, A...>::closure(lambda &&o)
noexcept
:F<bool (A...)>
{
[o(std::move(o))](A&&... a)
{
o(std::forward<A>(a)...);
return true;
}
}
{}