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//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP___MUTEX_ONCE_FLAG_H
#define _LIBCPP___MUTEX_ONCE_FLAG_H
#include <__config>
#include <__functional/invoke.h>
#include <__memory/shared_ptr.h> // __libcpp_acquire_load
#include <__tuple/tuple_indices.h>
#include <__tuple/tuple_size.h>
#include <__utility/forward.h>
#include <__utility/move.h>
#include <cstdint>
#ifndef _LIBCPP_CXX03_LANG
# include <tuple>
#endif
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_BEGIN_NAMESPACE_STD
struct _LIBCPP_TEMPLATE_VIS once_flag;
#ifndef _LIBCPP_CXX03_LANG
template <class _Callable, class... _Args>
_LIBCPP_HIDE_FROM_ABI void call_once(once_flag&, _Callable&&, _Args&&...);
#else // _LIBCPP_CXX03_LANG
template <class _Callable>
_LIBCPP_HIDE_FROM_ABI void call_once(once_flag&, _Callable&);
template <class _Callable>
_LIBCPP_HIDE_FROM_ABI void call_once(once_flag&, const _Callable&);
#endif // _LIBCPP_CXX03_LANG
struct _LIBCPP_TEMPLATE_VIS once_flag {
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR once_flag() _NOEXCEPT : __state_(_Unset) {}
once_flag(const once_flag&) = delete;
once_flag& operator=(const once_flag&) = delete;
#if defined(_LIBCPP_ABI_MICROSOFT)
typedef uintptr_t _State_type;
#else
typedef unsigned long _State_type;
#endif
static const _State_type _Unset = 0;
static const _State_type _Pending = 1;
static const _State_type _Complete = ~_State_type(0);
private:
_State_type __state_;
#ifndef _LIBCPP_CXX03_LANG
template <class _Callable, class... _Args>
friend void call_once(once_flag&, _Callable&&, _Args&&...);
#else // _LIBCPP_CXX03_LANG
template <class _Callable>
friend void call_once(once_flag&, _Callable&);
template <class _Callable>
friend void call_once(once_flag&, const _Callable&);
#endif // _LIBCPP_CXX03_LANG
};
#ifndef _LIBCPP_CXX03_LANG
template <class _Fp>
class __call_once_param {
_Fp& __f_;
public:
_LIBCPP_HIDE_FROM_ABI explicit __call_once_param(_Fp& __f) : __f_(__f) {}
_LIBCPP_HIDE_FROM_ABI void operator()() {
typedef typename __make_tuple_indices<tuple_size<_Fp>::value, 1>::type _Index;
__execute(_Index());
}
private:
template <size_t... _Indices>
_LIBCPP_HIDE_FROM_ABI void __execute(__tuple_indices<_Indices...>) {
std::__invoke(std::get<0>(std::move(__f_)), std::get<_Indices>(std::move(__f_))...);
}
};
#else
template <class _Fp>
class __call_once_param {
_Fp& __f_;
public:
_LIBCPP_HIDE_FROM_ABI explicit __call_once_param(_Fp& __f) : __f_(__f) {}
_LIBCPP_HIDE_FROM_ABI void operator()() { __f_(); }
};
#endif
template <class _Fp>
void _LIBCPP_HIDE_FROM_ABI __call_once_proxy(void* __vp) {
__call_once_param<_Fp>* __p = static_cast<__call_once_param<_Fp>*>(__vp);
(*__p)();
}
_LIBCPP_EXPORTED_FROM_ABI void __call_once(volatile once_flag::_State_type&, void*, void (*)(void*));
#ifndef _LIBCPP_CXX03_LANG
template <class _Callable, class... _Args>
inline _LIBCPP_HIDE_FROM_ABI void call_once(once_flag& __flag, _Callable&& __func, _Args&&... __args) {
if (__libcpp_acquire_load(&__flag.__state_) != once_flag::_Complete) {
typedef tuple<_Callable&&, _Args&&...> _Gp;
_Gp __f(std::forward<_Callable>(__func), std::forward<_Args>(__args)...);
__call_once_param<_Gp> __p(__f);
std::__call_once(__flag.__state_, &__p, &__call_once_proxy<_Gp>);
}
}
#else // _LIBCPP_CXX03_LANG
template <class _Callable>
inline _LIBCPP_HIDE_FROM_ABI void call_once(once_flag& __flag, _Callable& __func) {
if (__libcpp_acquire_load(&__flag.__state_) != once_flag::_Complete) {
__call_once_param<_Callable> __p(__func);
std::__call_once(__flag.__state_, &__p, &__call_once_proxy<_Callable>);
}
}
template <class _Callable>
inline _LIBCPP_HIDE_FROM_ABI void call_once(once_flag& __flag, const _Callable& __func) {
if (__libcpp_acquire_load(&__flag.__state_) != once_flag::_Complete) {
__call_once_param<const _Callable> __p(__func);
std::__call_once(__flag.__state_, &__p, &__call_once_proxy<const _Callable>);
}
}
#endif // _LIBCPP_CXX03_LANG
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP___MUTEX_ONCE_FLAG_H
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