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construct/include/ircd/mods/sym_ptr.h

168 lines
3.5 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_MODS_SYM_PTR_H
namespace ircd::mods
{
struct sym_ptr;
template<class F,
class... args,
typename std::enable_if<!std::is_member_pointer<F>::value>::type * = nullptr>
decltype(auto) invoke(F *const &f, args&&... a);
template<class F,
class O,
class... args,
typename std::enable_if<std::is_member_pointer<F>::value>::type * = nullptr>
decltype(auto) invoke(F *const &f, O *const &o, args&&... a);
}
/// Representation of a symbol in a loaded library (non-template; low level).
///
class ircd::mods::sym_ptr
:std::weak_ptr<mod>
{
void *ptr {nullptr};
public:
bool operator!() const;
explicit operator bool() const;
template<class T> const T *get() const;
template<class T> const T *operator->() const;
template<class T> const T &operator*() const;
template<class T, class... args> decltype(auto) operator()(args&&... a) const;
void *&get();
template<class T> T *get();
template<class T> T *operator->();
template<class T> T &operator*();
explicit sym_ptr(mod &, const string_view &symname);
sym_ptr(module, const string_view &symname);
sym_ptr(const string_view &modname, const string_view &symname);
sym_ptr() = default;
};
template<class T>
T &
ircd::mods::sym_ptr::operator*()
{
if(unlikely(expired()))
throw expired_symbol
{
"The reference to a symbol in another module is no longer valid"
};
assert(ptr);
return *operator-><T>();
}
template<class T>
T *
ircd::mods::sym_ptr::operator->()
{
return get<T>();
}
template<class T>
T *
ircd::mods::sym_ptr::get()
{
return reinterpret_cast<T *>(ptr);
}
inline void *&
ircd::mods::sym_ptr::get()
{
return ptr;
}
template<class T,
class... args>
decltype(auto)
ircd::mods::sym_ptr::operator()(args&&... a)
const
{
return invoke(get<T>(), std::forward<args>(a)...);
}
template<class T>
const T &
ircd::mods::sym_ptr::operator*()
const
{
if(unlikely(expired()))
throw expired_symbol
{
"The const reference to a symbol in another module is no longer valid"
};
assert(ptr);
return *operator-><T>();
}
template<class T>
const T *
ircd::mods::sym_ptr::operator->()
const
{
return get<T>();
}
template<class T>
const T *
ircd::mods::sym_ptr::get()
const
{
return reinterpret_cast<const T *>(ptr);
}
inline ircd::mods::sym_ptr::operator
bool()
const
{
return !operator!();
}
inline bool
ircd::mods::sym_ptr::operator!()
const
{
return !ptr || expired();
}
template<class F,
class O,
class... args,
typename std::enable_if<std::is_member_pointer<F>::value>::type *>
decltype(auto)
ircd::mods::invoke(F *const &f,
O *const &o,
args&&... a)
{
const void *const nv(f);
const F mfp(*reinterpret_cast<const F *>(&nv));
O *const volatile that(o);
return std::invoke(mfp, that, std::forward<args>(a)...);
}
template<class F,
class... args,
typename std::enable_if<!std::is_member_pointer<F>::value>::type *>
decltype(auto)
ircd::mods::invoke(F *const &f,
args&&... a)
{
return std::invoke(f, std::forward<args>(a)...);
}