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// Safe iterator implementation -*- C++ -*-
// Copyright (C) 2011-2021 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_local_iterator.h
* This file is a GNU debug extension to the Standard C++ Library.
*/
#ifndef _GLIBCXX_DEBUG_SAFE_LOCAL_ITERATOR_H
#define _GLIBCXX_DEBUG_SAFE_LOCAL_ITERATOR_H 1
#include <debug/safe_unordered_base.h>
#define _GLIBCXX_DEBUG_VERIFY_OPERANDS(_Lhs, _Rhs) \
_GLIBCXX_DEBUG_VERIFY(!_Lhs._M_singular() && !_Rhs._M_singular() \
|| (_Lhs.base() == _Iterator{} \
&& _Rhs.base() == _Iterator{}), \
_M_message(__msg_iter_compare_bad) \
._M_iterator(_Lhs, "lhs") \
._M_iterator(_Rhs, "rhs")); \
_GLIBCXX_DEBUG_VERIFY(_Lhs._M_can_compare(_Rhs), \
_M_message(__msg_compare_different) \
._M_iterator(_Lhs, "lhs") \
._M_iterator(_Rhs, "rhs")); \
_GLIBCXX_DEBUG_VERIFY(_Lhs._M_in_same_bucket(_Rhs), \
_M_message(__msg_local_iter_compare_bad) \
._M_iterator(_Lhs, "lhs") \
._M_iterator(_Rhs, "rhs"))
namespace __gnu_debug
{
/** \brief Safe iterator wrapper.
*
* The class template %_Safe_local_iterator is a wrapper around an
* iterator that tracks the iterator's movement among sequences and
* checks that operations performed on the "safe" iterator are
* legal. In additional to the basic iterator operations (which are
* validated, and then passed to the underlying iterator),
* %_Safe_local_iterator has member functions for iterator invalidation,
* attaching/detaching the iterator from sequences, and querying
* the iterator's state.
*/
template<typename _Iterator, typename _Sequence>
class _Safe_local_iterator
: private _Iterator
, public _Safe_local_iterator_base
{
typedef _Iterator _Iter_base;
typedef _Safe_local_iterator_base _Safe_base;
typedef typename _Sequence::size_type size_type;
typedef std::iterator_traits<_Iterator> _Traits;
typedef std::__are_same<
typename _Sequence::_Base::const_local_iterator,
_Iterator> _IsConstant;
typedef typename __gnu_cxx::__conditional_type<_IsConstant::__value,
typename _Sequence::_Base::local_iterator,
typename _Sequence::_Base::const_local_iterator>::__type
_OtherIterator;
typedef _Safe_local_iterator _Self;
typedef _Safe_local_iterator<_OtherIterator, _Sequence> _OtherSelf;
struct _Attach_single
{ };
_Safe_local_iterator(_Iterator __i, _Safe_sequence_base* __cont,
_Attach_single) noexcept
: _Iter_base(__i)
{ _M_attach_single(__cont); }
public:
typedef _Iterator iterator_type;
typedef typename _Traits::iterator_category iterator_category;
typedef typename _Traits::value_type value_type;
typedef typename _Traits::difference_type difference_type;
typedef typename _Traits::reference reference;
typedef typename _Traits::pointer pointer;
/// @post the iterator is singular and unattached
_Safe_local_iterator() noexcept : _Iter_base() { }
/**
* @brief Safe iterator construction from an unsafe iterator and
* its sequence.
*
* @pre @p seq is not NULL
* @post this is not singular
*/
_Safe_local_iterator(_Iterator __i, const _Safe_sequence_base* __cont)
: _Iter_base(__i), _Safe_base(__cont, _S_constant())
{
_GLIBCXX_DEBUG_VERIFY(!this->_M_singular(),
_M_message(__msg_init_singular)
._M_iterator(*this, "this"));
}
/**
* @brief Copy construction.
*/
_Safe_local_iterator(const _Safe_local_iterator& __x) noexcept
: _Iter_base(__x.base())
{
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// DR 408. Is vector<reverse_iterator<char*> > forbidden?
_GLIBCXX_DEBUG_VERIFY(!__x._M_singular()
|| __x.base() == _Iterator(),
_M_message(__msg_init_copy_singular)
._M_iterator(*this, "this")
._M_iterator(__x, "other"));
_M_attach(__x._M_sequence);
}
/**
* @brief Move construction.
* @post __x is singular and unattached
*/
_Safe_local_iterator(_Safe_local_iterator&& __x) noexcept
: _Iter_base()
{
_GLIBCXX_DEBUG_VERIFY(!__x._M_singular()
|| __x.base() == _Iterator(),
_M_message(__msg_init_copy_singular)
._M_iterator(*this, "this")
._M_iterator(__x, "other"));
auto __cont = __x._M_sequence;
__x._M_detach();
std::swap(base(), __x.base());
_M_attach(__cont);
}
/**
* @brief Converting constructor from a mutable iterator to a
* constant iterator.
*/
template<typename _MutableIterator>
_Safe_local_iterator(
const _Safe_local_iterator<_MutableIterator,
typename __gnu_cxx::__enable_if<_IsConstant::__value &&
std::__are_same<_MutableIterator, _OtherIterator>::__value,
_Sequence>::__type>& __x) noexcept
: _Iter_base(__x.base())
{
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// DR 408. Is vector<reverse_iterator<char*> > forbidden?
_GLIBCXX_DEBUG_VERIFY(!__x._M_singular()
|| __x.base() == _MutableIterator(),
_M_message(__msg_init_const_singular)
._M_iterator(*this, "this")
._M_iterator(__x, "other"));
_M_attach(__x._M_sequence);
}
/**
* @brief Copy assignment.
*/
_Safe_local_iterator&
operator=(const _Safe_local_iterator& __x)
{
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// DR 408. Is vector<reverse_iterator<char*> > forbidden?
_GLIBCXX_DEBUG_VERIFY(!__x._M_singular()
|| __x.base() == _Iterator(),
_M_message(__msg_copy_singular)
._M_iterator(*this, "this")
._M_iterator(__x, "other"));
if (this->_M_sequence && this->_M_sequence == __x._M_sequence)
{
__gnu_cxx::__scoped_lock __l(this->_M_get_mutex());
base() = __x.base();
_M_version = __x._M_sequence->_M_version;
}
else
{
_M_detach();
base() = __x.base();
_M_attach(__x._M_sequence);
}
return *this;
}
/**
* @brief Move assignment.
* @post __x is singular and unattached
*/
_Safe_local_iterator&
operator=(_Safe_local_iterator&& __x) noexcept
{
_GLIBCXX_DEBUG_VERIFY(!__x._M_singular()
|| __x.base() == _Iterator(),
_M_message(__msg_copy_singular)
._M_iterator(*this, "this")
._M_iterator(__x, "other"));
if (std::__addressof(__x) == this)
return *this;
if (this->_M_sequence && this->_M_sequence == __x._M_sequence)
{
__gnu_cxx::__scoped_lock __l(this->_M_get_mutex());
base() = __x.base();
_M_version = __x._M_sequence->_M_version;
}
else
{
_M_detach();
base() = __x.base();
_M_attach(__x._M_sequence);
}
__x._M_detach();
__x.base() = _Iterator();
return *this;
}
/**
* @brief Iterator dereference.
* @pre iterator is dereferenceable
*/
reference
operator*() const
{
_GLIBCXX_DEBUG_VERIFY(this->_M_dereferenceable(),
_M_message(__msg_bad_deref)
._M_iterator(*this, "this"));
return *base();
}
/**
* @brief Iterator dereference.
* @pre iterator is dereferenceable
*/
pointer
operator->() const
{
_GLIBCXX_DEBUG_VERIFY(this->_M_dereferenceable(),
_M_message(__msg_bad_deref)
._M_iterator(*this, "this"));
return base().operator->();
}
// ------ Input iterator requirements ------
/**
* @brief Iterator preincrement
* @pre iterator is incrementable
*/
_Safe_local_iterator&
operator++()
{
_GLIBCXX_DEBUG_VERIFY(this->_M_incrementable(),
_M_message(__msg_bad_inc)
._M_iterator(*this, "this"));
__gnu_cxx::__scoped_lock __l(this->_M_get_mutex());
++base();
return *this;
}
/**
* @brief Iterator postincrement
* @pre iterator is incrementable
*/
_Safe_local_iterator
operator++(int)
{
_GLIBCXX_DEBUG_VERIFY(this->_M_incrementable(),
_M_message(__msg_bad_inc)
._M_iterator(*this, "this"));
__gnu_cxx::__scoped_lock __l(this->_M_get_mutex());
return _Safe_local_iterator(base()++, this->_M_sequence,
_Attach_single());
}
// ------ Utilities ------
/// Determine if this is a constant iterator.
static constexpr bool
_S_constant()
{ return _IsConstant::__value; }
/**
* @brief Return the underlying iterator
*/
_Iterator&
base() noexcept { return *this; }
const _Iterator&
base() const noexcept { return *this; }
/**
* @brief Return the bucket
*/
size_type
bucket() const { return base()._M_get_bucket(); }
/**
* @brief Conversion to underlying non-debug iterator to allow
* better interaction with non-debug containers.
*/
operator _Iterator() const { return *this; }
/** Attach iterator to the given sequence. */
void
_M_attach(_Safe_sequence_base* __seq)
{ _Safe_base::_M_attach(__seq, _S_constant()); }
/** Likewise, but not thread-safe. */
void
_M_attach_single(_Safe_sequence_base* __seq)
{ _Safe_base::_M_attach_single(__seq, _S_constant()); }
/// Is the iterator dereferenceable?
bool
_M_dereferenceable() const
{ return !this->_M_singular() && !_M_is_end(); }
/// Is the iterator incrementable?
bool
_M_incrementable() const
{ return !this->_M_singular() && !_M_is_end(); }
// Is the iterator range [*this, __rhs) valid?
bool
_M_valid_range(const _Safe_local_iterator& __rhs,
std::pair<difference_type,
_Distance_precision>& __dist_info) const;
// Get distance to __rhs.
typename _Distance_traits<_Iterator>::__type
_M_get_distance_to(const _Safe_local_iterator& __rhs) const;
// The sequence this iterator references.
typename __gnu_cxx::__conditional_type<
_IsConstant::__value, const _Sequence*, _Sequence*>::__type
_M_get_sequence() const
{ return static_cast<_Sequence*>(_M_sequence); }
/// Is this iterator equal to the sequence's begin(bucket) iterator?
bool _M_is_begin() const
{ return base() == _M_get_sequence()->_M_base().begin(bucket()); }
/// Is this iterator equal to the sequence's end(bucket) iterator?
bool _M_is_end() const
{ return base() == _M_get_sequence()->_M_base().end(bucket()); }
/// Is this iterator part of the same bucket as the other one?
template<typename _Other>
bool
_M_in_same_bucket(const _Safe_local_iterator<_Other,
_Sequence>& __other) const
{ return bucket() == __other.bucket(); }
friend inline bool
operator==(const _Self& __lhs, const _OtherSelf& __rhs) noexcept
{
_GLIBCXX_DEBUG_VERIFY_OPERANDS(__lhs, __rhs);
return __lhs.base() == __rhs.base();
}
friend inline bool
operator==(const _Self& __lhs, const _Self& __rhs) noexcept
{
_GLIBCXX_DEBUG_VERIFY_OPERANDS(__lhs, __rhs);
return __lhs.base() == __rhs.base();
}
friend inline bool
operator!=(const _Self& __lhs, const _OtherSelf& __rhs) noexcept
{
_GLIBCXX_DEBUG_VERIFY_OPERANDS(__lhs, __rhs);
return __lhs.base() != __rhs.base();
}
friend inline bool
operator!=(const _Self& __lhs, const _Self& __rhs) noexcept
{
_GLIBCXX_DEBUG_VERIFY_OPERANDS(__lhs, __rhs);
return __lhs.base() != __rhs.base();
}
};
/** Safe local iterators know how to check if they form a valid range. */
template<typename _Iterator, typename _Sequence>
inline bool
__valid_range(const _Safe_local_iterator<_Iterator, _Sequence>& __first,
const _Safe_local_iterator<_Iterator, _Sequence>& __last,
typename _Distance_traits<_Iterator>::__type& __dist_info)
{ return __first._M_valid_range(__last, __dist_info); }
template<typename _Iterator, typename _Sequence>
inline bool
__valid_range(const _Safe_local_iterator<_Iterator, _Sequence>& __first,
const _Safe_local_iterator<_Iterator, _Sequence>& __last)
{
typename _Distance_traits<_Iterator>::__type __dist_info;
return __first._M_valid_range(__last, __dist_info);
}
#if __cplusplus < 201103L
template<typename _Iterator, typename _Sequence>
struct _Unsafe_type<_Safe_local_iterator<_Iterator, _Sequence> >
{ typedef _Iterator _Type; };
#endif
template<typename _Iterator, typename _Sequence>
inline _Iterator
__unsafe(const _Safe_local_iterator<_Iterator, _Sequence>& __it)
{ return __it.base(); }
} // namespace __gnu_debug
#undef _GLIBCXX_DEBUG_VERIFY_OPERANDS
#include <debug/safe_local_iterator.tcc>
#endif
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