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construct/include/ircd/m/import.h

103 lines
2.1 KiB
C++

// Matrix Construct
//
// Copyright (C) Matrix Construct Developers, Authors & Contributors
// Copyright (C) 2016-2018 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_M_IMPORT_H
namespace ircd::m
{
template<class prototype> struct import;
struct imports extern imports;
}
struct ircd::m::imports
:std::map<std::string, ircd::module, std::less<>>
{
void init();
};
template<class prototype>
struct ircd::m::import
:mods::import<prototype>
{
std::string modname;
std::string symname;
void reload();
public:
template<class... args> auto operator()(args&&... a);
prototype *operator->();
prototype &operator*();
operator prototype &();
import(std::string modname, std::string symname);
};
template<class prototype>
ircd::m::import<prototype>::import(std::string modname,
std::string symname)
:mods::import<prototype>{}
,modname{std::move(modname)}
,symname{std::move(symname)}
{}
template<class prototype>
ircd::m::import<prototype>::operator
prototype &()
{
return this->operator*();
}
template<class prototype>
prototype &
ircd::m::import<prototype>::operator*()
{
return *this->operator->();
}
template<class prototype>
prototype *
ircd::m::import<prototype>::operator->()
{
if(unlikely(!*this))
reload();
return mods::import<prototype>::operator->();
}
template<class prototype>
template<class... args>
auto
ircd::m::import<prototype>::operator()(args&&... a)
{
if(unlikely(!*this))
reload();
return mods::import<prototype>::operator()(std::forward<args>(a)...);
}
template<class prototype>
void
ircd::m::import<prototype>::reload()
try
{
auto &import(static_cast<mods::import<prototype> &>(*this));
import = { imports.at(modname), symname };
}
catch(const std::out_of_range &e)
{
throw m::UNAVAILABLE
{
"Sorry, %s in %s is currently unavailable.",
symname,
modname
};
}