1 /* 2 * Copyright (C) 2012 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef ART_RUNTIME_SAFE_MAP_H_ 18 #define ART_RUNTIME_SAFE_MAP_H_ 19 20 #include <map> 21 #include <memory> 22 23 #include "base/allocator.h" 24 #include "base/logging.h" 25 26 namespace art { 27 28 // Equivalent to std::map, but without operator[] and its bug-prone semantics (in particular, 29 // the implicit insertion of a default-constructed value on failed lookups). 30 template <typename K, typename V, typename Comparator = std::less<K>, 31 typename Allocator = TrackingAllocator<std::pair<const K, V>, kAllocatorTagSafeMap>> 32 class SafeMap { 33 private: 34 typedef SafeMap<K, V, Comparator, Allocator> Self; 35 36 public: 37 typedef typename ::std::map<K, V, Comparator, Allocator>::key_compare key_compare; 38 typedef typename ::std::map<K, V, Comparator, Allocator>::value_compare value_compare; 39 typedef typename ::std::map<K, V, Comparator, Allocator>::allocator_type allocator_type; 40 typedef typename ::std::map<K, V, Comparator, Allocator>::iterator iterator; 41 typedef typename ::std::map<K, V, Comparator, Allocator>::const_iterator const_iterator; 42 typedef typename ::std::map<K, V, Comparator, Allocator>::size_type size_type; 43 typedef typename ::std::map<K, V, Comparator, Allocator>::key_type key_type; 44 typedef typename ::std::map<K, V, Comparator, Allocator>::value_type value_type; 45 46 SafeMap() = default; 47 explicit SafeMap(const key_compare& cmp, const allocator_type& allocator = allocator_type()) 48 : map_(cmp, allocator) { 49 } 50 51 Self& operator=(const Self& rhs) { 52 map_ = rhs.map_; 53 return *this; 54 } 55 56 allocator_type get_allocator() const { return map_.get_allocator(); } 57 key_compare key_comp() const { return map_.key_comp(); } 58 value_compare value_comp() const { return map_.value_comp(); } 59 60 iterator begin() { return map_.begin(); } 61 const_iterator begin() const { return map_.begin(); } 62 iterator end() { return map_.end(); } 63 const_iterator end() const { return map_.end(); } 64 65 bool empty() const { return map_.empty(); } 66 size_type size() const { return map_.size(); } 67 68 void swap(Self& other) { map_.swap(other.map_); } 69 void clear() { map_.clear(); } 70 iterator erase(iterator it) { return map_.erase(it); } 71 size_type erase(const K& k) { return map_.erase(k); } 72 73 iterator find(const K& k) { return map_.find(k); } 74 const_iterator find(const K& k) const { return map_.find(k); } 75 76 iterator lower_bound(const K& k) { return map_.lower_bound(k); } 77 const_iterator lower_bound(const K& k) const { return map_.lower_bound(k); } 78 79 size_type count(const K& k) const { return map_.count(k); } 80 81 // Note that unlike std::map's operator[], this doesn't return a reference to the value. 82 V Get(const K& k) const { 83 const_iterator it = map_.find(k); 84 DCHECK(it != map_.end()); 85 return it->second; 86 } 87 88 // Used to insert a new mapping. 89 iterator Put(const K& k, const V& v) { 90 std::pair<iterator, bool> result = map_.emplace(k, v); 91 DCHECK(result.second); // Check we didn't accidentally overwrite an existing value. 92 return result.first; 93 } 94 95 // Used to insert a new mapping at a known position for better performance. 96 iterator PutBefore(iterator pos, const K& k, const V& v) { 97 // Check that we're using the correct position and the key is not in the map. 98 DCHECK(pos == map_.end() || map_.key_comp()(k, pos->first)); 99 DCHECK(pos == map_.begin() || map_.key_comp()((--iterator(pos))->first, k)); 100 return map_.emplace_hint(pos, k, v); 101 } 102 103 // Used to insert a new mapping or overwrite an existing mapping. Note that if the value type 104 // of this container is a pointer, any overwritten pointer will be lost and if this container 105 // was the owner, you have a leak. 106 void Overwrite(const K& k, const V& v) { 107 std::pair<iterator, bool> result = map_.insert(std::make_pair(k, v)); 108 if (!result.second) { 109 // Already there - update the value for the existing key 110 result.first->second = v; 111 } 112 } 113 114 bool Equals(const Self& rhs) const { 115 return map_ == rhs.map_; 116 } 117 118 private: 119 ::std::map<K, V, Comparator, Allocator> map_; 120 }; 121 122 template <typename K, typename V, typename Comparator, typename Allocator> 123 bool operator==(const SafeMap<K, V, Comparator, Allocator>& lhs, 124 const SafeMap<K, V, Comparator, Allocator>& rhs) { 125 return lhs.Equals(rhs); 126 } 127 128 template <typename K, typename V, typename Comparator, typename Allocator> 129 bool operator!=(const SafeMap<K, V, Comparator, Allocator>& lhs, 130 const SafeMap<K, V, Comparator, Allocator>& rhs) { 131 return !(lhs == rhs); 132 } 133 134 template<class Key, class T, AllocatorTag kTag, class Compare = std::less<Key>> 135 class AllocationTrackingSafeMap : public SafeMap< 136 Key, T, Compare, TrackingAllocator<std::pair<Key, T>, kTag>> { 137 }; 138 139 } // namespace art 140 141 #endif // ART_RUNTIME_SAFE_MAP_H_ 142
