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construct/include/ircd/util/instance_map.h
2022-07-18 16:58:02 -07:00

160 lines
3.3 KiB
C++

// Matrix Construct
//
// Copyright (C) Matrix Construct Developers, Authors & Contributors
// Copyright (C) 2016-2022 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_INSTANCE_MAP_H
namespace ircd {
inline namespace util
{
template<class K,
class T,
class C = std::less<K>>
struct instance_map;
}}
/// See instance_list for purpose and overview.
template<class K,
class T,
class C>
struct ircd::util::instance_map
{
static std::map<K, T *, C> map;
protected:
typename decltype(map)::iterator it;
template<class Key>
instance_map(const typename decltype(map)::const_iterator &hint, Key&&);
template<class Key>
instance_map(Key&&);
instance_map(instance_map &&) noexcept;
instance_map(const instance_map &);
instance_map &operator=(instance_map &&) noexcept;
instance_map &operator=(const instance_map &);
~instance_map() noexcept;
};
template<class K,
class T,
class C>
template<class Key>
inline
ircd::util::instance_map<K, T, C>::instance_map(Key&& key)
{
auto [it, ok]
{
map.emplace(std::forward<Key>(key), static_cast<T *>(this))
};
if(unlikely(!ok))
throw std::invalid_argument
{
"Instance mapping to this key already exists."
};
this->it = std::move(it);
}
template<class K,
class T,
class C>
template<class Key>
inline
ircd::util::instance_map<K, T, C>::instance_map(const typename decltype(map)::const_iterator &hint,
Key&& key)
{
auto [it, ok]
{
map.emplace_hint(hint, std::forward<Key>(key), static_cast<T *>(this))
};
if(unlikely(!ok))
throw std::invalid_argument
{
"Instance mapping to this key already exists."
};
this->it = std::move(it);
}
template<class K,
class T,
class C>
inline
ircd::util::instance_map<K, T, C>::instance_map(instance_map &&other)
noexcept
:it
{
std::move(other.it)
}
{
if(it != end(map))
{
it->second = static_cast<T *>(this);
other.it = end(map);
}
}
template<class K,
class T,
class C>
inline
ircd::util::instance_map<K, T, C>::instance_map(const instance_map &other)
:it
{
other.it != end(map)?
map.emplace_hint(other.it, other.it->first, static_cast<T *>(this)):
end(map)
}
{}
template<class K,
class T,
class C>
inline ircd::util::instance_map<K, T, C> &
ircd::util::instance_map<K, T, C>::operator=(instance_map &&other)
noexcept
{
this->~instance_map();
it = std::move(other.it);
if(it != end(map))
it->second = static_cast<T *>(this);
other.it = end(map);
return *this;
}
template<class K,
class T,
class C>
inline ircd::util::instance_map<K, T, C> &
ircd::util::instance_map<K, T, C>::operator=(const instance_map &other)
{
this->~instance_map();
it = other.it != end(map)?
map.emplace_hint(other.it, other.it->first, static_cast<T *>(this)):
end(map);
return *this;
}
template<class K,
class T,
class C>
inline
ircd::util::instance_map<K, T, C>::~instance_map()
noexcept
{
if(it != end(map))
map.erase(it);
}