safe_container.h
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// Safe container implementation -*- C++ -*-
// Copyright (C) 2014-2026 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
/** @file debug/safe_container.h
* This file is a GNU debug extension to the Standard C++ Library.
*/
#ifndef _GLIBCXX_DEBUG_SAFE_CONTAINER_H
#define _GLIBCXX_DEBUG_SAFE_CONTAINER_H 1
#include <ext/alloc_traits.h>
namespace __gnu_debug
{
/// Safe class dealing with some allocator dependent operations.
template<typename _SafeContainer,
typename _Alloc,
template<typename> class _SafeBase,
bool _IsCxx11AllocatorAware = true>
class _Safe_container
: public _SafeBase<_SafeContainer>
{
typedef _SafeBase<_SafeContainer> _Base;
_GLIBCXX20_CONSTEXPR
const _SafeContainer&
_M_cont() const _GLIBCXX_NOEXCEPT
{ return *static_cast<const _SafeContainer*>(this); }
protected:
#if __cplusplus >= 201103L
_Safe_container() = default;
_Safe_container(const _Safe_container&) = default;
_Safe_container(_Safe_container&&) = default;
private:
_GLIBCXX20_CONSTEXPR
void
_M_swap_base(const _Safe_container& __x) const noexcept
{ _Base::_M_swap(__x); }
_GLIBCXX20_CONSTEXPR
_Safe_container(_Safe_container&& __x, const _Alloc&, std::true_type)
: _Safe_container(std::move(__x))
{ }
_GLIBCXX20_CONSTEXPR
_Safe_container(_Safe_container&& __x, const _Alloc& __a, std::false_type)
: _Safe_container()
{
if (!std::__is_constant_evaluated())
{
if (__x._M_cont().get_allocator() == __a)
_M_swap_base(__x);
else
__x._M_invalidate_all();
}
}
protected:
_GLIBCXX20_CONSTEXPR
_Safe_container(_Safe_container&& __x, const _Alloc& __a)
: _Safe_container(std::move(__x), __a,
typename std::allocator_traits<_Alloc>::is_always_equal{})
{ }
#endif
#if __cplusplus < 201103L
_Safe_container&
operator=(const _Safe_container& __x)
{
_Base::operator=(__x);
return *this;
}
void
_M_swap(const _Safe_container& __x) const throw()
{ _Base::_M_swap(__x); }
#else
_GLIBCXX20_CONSTEXPR
_Safe_container&
operator=(const _Safe_container&) noexcept = default;
_GLIBCXX20_CONSTEXPR
_Safe_container&
operator=(_Safe_container&& __x) noexcept
{
if (std::__is_constant_evaluated())
return *this;
if (std::__addressof(__x) == this)
{
// Standard containers have a valid but unspecified value after
// self-move, so we invalidate all debug iterators even if the
// underlying container happens to preserve its contents.
this->_M_invalidate_all();
return *this;
}
if (_IsCxx11AllocatorAware)
{
typedef __gnu_cxx::__alloc_traits<_Alloc> _Alloc_traits;
bool __xfer_memory = _Alloc_traits::_S_propagate_on_move_assign()
|| _M_cont().get_allocator() == __x._M_cont().get_allocator();
if (__xfer_memory)
_M_swap_base(__x);
else
this->_M_invalidate_all();
}
else
_M_swap_base(__x);
__x._M_invalidate_all();
return *this;
}
_GLIBCXX20_CONSTEXPR
void
_M_swap(const _Safe_container& __x) const noexcept
{
if (_IsCxx11AllocatorAware)
{
typedef __gnu_cxx::__alloc_traits<_Alloc> _Alloc_traits;
if (!_Alloc_traits::_S_propagate_on_swap())
__glibcxx_check_equal_allocs(this->_M_cont()._M_base(),
__x._M_cont()._M_base());
}
_M_swap_base(__x);
}
#endif
};
} // namespace __gnu_debug
#endif
std::true_type
__bool_constant< true > true_type
The type used as a compile-time boolean with true value.
Definition type_traits:119
std::false_type
__bool_constant< false > false_type
The type used as a compile-time boolean with false value.
Definition type_traits:122
std::move
constexpr std::remove_reference< _Tp >::type && move(_Tp &&__t) noexcept
Convert a value to an rvalue.
Definition move.h:138
std::__addressof
constexpr _Tp * __addressof(_Tp &__r) noexcept
Same as C++11 std::addressof.
Definition move.h:52
__gnu_debug
GNU debug classes for public use.
Definition boost_concept_check.h:60
std::allocator_traits::is_always_equal
typename __detected_or_t< is_empty< _Alloc >, __equal, _Alloc >::type is_always_equal
Whether all instances of the allocator type compare equal.
Definition bits/alloc_traits.h:365
__gnu_cxx::__alloc_traits
Uniform interface to C++98 and C++11 allocators.
Definition ext/alloc_traits.h:51
alloc_traits.h