135 lines
3.5 KiB
C++
135 lines
3.5 KiB
C++
/* A safe iterator for GDB, the GNU debugger.
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Copyright (C) 2018-2022 Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#ifndef COMMON_SAFE_ITERATOR_H
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#define COMMON_SAFE_ITERATOR_H
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/* A forward iterator that wraps Iterator, such that when iterating
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with iterator IT, it is possible to delete *IT without invalidating
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IT. Suitably wrapped in a range type and used with range-for, this
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allow convenient patterns like this:
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// range_safe() returns a range type whose begin()/end() methods
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// return safe iterators.
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for (foo *f : range_safe ())
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{
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if (f->should_delete ())
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{
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// The ++it operation implicitly done by the range-for is
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// still OK after this.
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delete f;
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}
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}
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*/
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template<typename Iterator>
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class basic_safe_iterator
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{
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public:
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typedef basic_safe_iterator self_type;
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typedef typename Iterator::value_type value_type;
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typedef typename Iterator::reference reference;
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typedef typename Iterator::pointer pointer;
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typedef typename Iterator::iterator_category iterator_category;
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typedef typename Iterator::difference_type difference_type;
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/* Construct the begin iterator using the given arguments; the end iterator is
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default constructed. */
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template<typename... Args>
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explicit basic_safe_iterator (Args &&...args)
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: m_it (std::forward<Args> (args)...),
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m_next (m_it)
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{
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if (m_it != m_end)
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++m_next;
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}
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/* Construct the iterator using the first argument, and construct
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the end iterator using the second argument. */
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template<typename Arg>
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explicit basic_safe_iterator (Arg &&arg, Arg &&arg2)
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: m_it (std::forward<Arg> (arg)),
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m_next (m_it),
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m_end (std::forward<Arg> (arg2))
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{
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if (m_it != m_end)
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++m_next;
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}
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/* Create a one-past-end iterator. */
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basic_safe_iterator ()
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{}
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value_type operator* () const { return *m_it; }
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self_type &operator++ ()
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{
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m_it = m_next;
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if (m_it != m_end)
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++m_next;
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return *this;
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}
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bool operator== (const self_type &other) const
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{ return m_it == other.m_it; }
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bool operator!= (const self_type &other) const
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{ return m_it != other.m_it; }
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private:
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/* The current element. */
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Iterator m_it {};
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/* The next element. Always one element ahead of M_IT. */
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Iterator m_next {};
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/* A one-past-end iterator. */
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Iterator m_end {};
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};
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/* A range adapter that wraps another range, and then returns safe
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iterators wrapping the original range's iterators. */
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template<typename Range>
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class basic_safe_range
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{
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public:
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typedef basic_safe_iterator<typename Range::iterator> iterator;
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explicit basic_safe_range (Range range)
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: m_range (range)
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{
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}
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iterator begin ()
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{
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return iterator (m_range.begin (), m_range.end ());
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}
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iterator end ()
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{
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return iterator (m_range.end (), m_range.end ());
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}
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private:
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Range m_range;
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};
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#endif /* COMMON_SAFE_ITERATOR_H */
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