1 // Safe container/iterator base implementation -*- C++ -*- 2 3 // Copyright (C) 2011-2018 Free Software Foundation, Inc. 4 // 5 // This file is part of the GNU ISO C++ Library. This library is free 6 // software; you can redistribute it and/or modify it under the 7 // terms of the GNU General Public License as published by the 8 // Free Software Foundation; either version 3, or (at your option) 9 // any later version. 10 11 // This library is distributed in the hope that it will be useful, 12 // but WITHOUT ANY WARRANTY; without even the implied warranty of 13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 // GNU General Public License for more details. 15 16 // Under Section 7 of GPL version 3, you are granted additional 17 // permissions described in the GCC Runtime Library Exception, version 18 // 3.1, as published by the Free Software Foundation. 19 20 // You should have received a copy of the GNU General Public License and 21 // a copy of the GCC Runtime Library Exception along with this program; 22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 23 // <http://www.gnu.org/licenses/>. 24 25 /** @file debug/safe_unordered_base.h 26 * This file is a GNU debug extension to the Standard C++ Library. 27 */ 28 29 #ifndef _GLIBCXX_DEBUG_SAFE_UNORDERED_BASE_H 30 #define _GLIBCXX_DEBUG_SAFE_UNORDERED_BASE_H 1 31 32 #include <debug/safe_base.h> 33 34 namespace __gnu_debug 35 { 36 class _Safe_unordered_container_base; 37 38 /** \brief Basic functionality for a @a safe iterator. 39 * 40 * The %_Safe_local_iterator_base base class implements the functionality 41 * of a safe local iterator that is not specific to a particular iterator 42 * type. It contains a pointer back to the container it references 43 * along with iterator version information and pointers to form a 44 * doubly-linked list of local iterators referenced by the container. 45 * 46 * This class must not perform any operations that can throw an 47 * exception, or the exception guarantees of derived iterators will 48 * be broken. 49 */ 50 class _Safe_local_iterator_base : public _Safe_iterator_base 51 { 52 protected: 53 /** Initializes the iterator and makes it singular. */ 54 _Safe_local_iterator_base() 55 { } 56 57 /** Initialize the iterator to reference the container pointed to 58 * by @p __seq. @p __constant is true when we are initializing a 59 * constant local iterator, and false if it is a mutable local iterator. 60 * Note that @p __seq may be NULL, in which case the iterator will be 61 * singular. Otherwise, the iterator will reference @p __seq and 62 * be nonsingular. 63 */ 64 _Safe_local_iterator_base(const _Safe_sequence_base* __seq, bool __constant) 65 { this->_M_attach(const_cast<_Safe_sequence_base*>(__seq), __constant); } 66 67 /** Initializes the iterator to reference the same container that 68 @p __x does. @p __constant is true if this is a constant 69 iterator, and false if it is mutable. */ 70 _Safe_local_iterator_base(const _Safe_local_iterator_base& __x, 71 bool __constant) 72 { this->_M_attach(__x._M_sequence, __constant); } 73 74 ~_Safe_local_iterator_base() { this->_M_detach(); } 75 76 _Safe_unordered_container_base* 77 _M_get_container() const noexcept; 78 79 /** Attaches this iterator to the given container, detaching it 80 * from whatever container it was attached to originally. If the 81 * new container is the NULL pointer, the iterator is left 82 * unattached. 83 */ 84 void 85 _M_attach(_Safe_sequence_base* __seq, bool __constant); 86 87 /** Likewise, but not thread-safe. */ 88 void 89 _M_attach_single(_Safe_sequence_base* __seq, bool __constant) throw (); 90 91 /** Detach the iterator for whatever container it is attached to, 92 * if any. 93 */ 94 void 95 _M_detach(); 96 97 /** Likewise, but not thread-safe. */ 98 void 99 _M_detach_single() throw (); 100 }; 101 102 /** 103 * @brief Base class that supports tracking of local iterators that 104 * reference an unordered container. 105 * 106 * The %_Safe_unordered_container_base class provides basic support for 107 * tracking iterators into an unordered container. Containers that track 108 * iterators must derived from %_Safe_unordered_container_base publicly, so 109 * that safe iterators (which inherit _Safe_iterator_base) can 110 * attach to them. This class contains four linked lists of 111 * iterators, one for constant iterators, one for mutable 112 * iterators, one for constant local iterators, one for mutable local 113 * iterators and a version number that allows very fast 114 * invalidation of all iterators that reference the container. 115 * 116 * This class must ensure that no operation on it may throw an 117 * exception, otherwise @a safe containers may fail to provide the 118 * exception-safety guarantees required by the C++ standard. 119 */ 120 class _Safe_unordered_container_base : public _Safe_sequence_base 121 { 122 friend class _Safe_local_iterator_base; 123 typedef _Safe_sequence_base _Base; 124 125 public: 126 /// The list of mutable local iterators that reference this container 127 _Safe_iterator_base* _M_local_iterators; 128 129 /// The list of constant local iterators that reference this container 130 _Safe_iterator_base* _M_const_local_iterators; 131 132 protected: 133 // Initialize with a version number of 1 and no iterators 134 _Safe_unordered_container_base() noexcept 135 : _M_local_iterators(nullptr), _M_const_local_iterators(nullptr) 136 { } 137 138 // Copy constructor does not copy iterators. 139 _Safe_unordered_container_base(const _Safe_unordered_container_base&) 140 noexcept 141 : _Safe_unordered_container_base() { } 142 143 // When moved unordered containers iterators are swapped. 144 _Safe_unordered_container_base(_Safe_unordered_container_base&& __x) 145 noexcept 146 : _Safe_unordered_container_base() 147 { this->_M_swap(__x); } 148 149 /** Notify all iterators that reference this container that the 150 container is being destroyed. */ 151 ~_Safe_unordered_container_base() noexcept 152 { this->_M_detach_all(); } 153 154 /** Detach all iterators, leaving them singular. */ 155 void 156 _M_detach_all(); 157 158 /** Swap this container with the given container. This operation 159 * also swaps ownership of the iterators, so that when the 160 * operation is complete all iterators that originally referenced 161 * one container now reference the other container. 162 */ 163 void 164 _M_swap(_Safe_unordered_container_base& __x) noexcept; 165 166 private: 167 /** Attach an iterator to this container. */ 168 void 169 _M_attach_local(_Safe_iterator_base* __it, bool __constant); 170 171 /** Likewise but not thread safe. */ 172 void 173 _M_attach_local_single(_Safe_iterator_base* __it, bool __constant) throw (); 174 175 /** Detach an iterator from this container */ 176 void 177 _M_detach_local(_Safe_iterator_base* __it); 178 179 /** Likewise but not thread safe. */ 180 void 181 _M_detach_local_single(_Safe_iterator_base* __it) throw (); 182 }; 183 } // namespace __gnu_debug 184 185 #endif 186