summaryrefslogtreecommitdiffstats
path: root/runtime/safe_map.h
blob: 402c7e9cb52419394299a5fece44ee5c263f560a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
/*
 * Copyright (C) 2012 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef ART_RUNTIME_SAFE_MAP_H_
#define ART_RUNTIME_SAFE_MAP_H_

#include <map>
#include <memory>

#include "base/allocator.h"
#include "base/logging.h"

namespace art {

// Equivalent to std::map, but without operator[] and its bug-prone semantics (in particular,
// the implicit insertion of a default-constructed value on failed lookups).
template <typename K, typename V, typename Comparator = std::less<K>,
          typename Allocator = TrackingAllocator<std::pair<const K, V>, kAllocatorTagSafeMap>>
class SafeMap {
 private:
  typedef SafeMap<K, V, Comparator, Allocator> Self;

 public:
  typedef typename ::std::map<K, V, Comparator, Allocator>::key_compare key_compare;
  typedef typename ::std::map<K, V, Comparator, Allocator>::value_compare value_compare;
  typedef typename ::std::map<K, V, Comparator, Allocator>::allocator_type allocator_type;
  typedef typename ::std::map<K, V, Comparator, Allocator>::iterator iterator;
  typedef typename ::std::map<K, V, Comparator, Allocator>::const_iterator const_iterator;
  typedef typename ::std::map<K, V, Comparator, Allocator>::size_type size_type;
  typedef typename ::std::map<K, V, Comparator, Allocator>::key_type key_type;
  typedef typename ::std::map<K, V, Comparator, Allocator>::value_type value_type;

  SafeMap() = default;
  SafeMap(const SafeMap&) = default;
  explicit SafeMap(const key_compare& cmp, const allocator_type& allocator = allocator_type())
    : map_(cmp, allocator) {
  }

  Self& operator=(const Self& rhs) {
    map_ = rhs.map_;
    return *this;
  }

  allocator_type get_allocator() const { return map_.get_allocator(); }
  key_compare key_comp() const { return map_.key_comp(); }
  value_compare value_comp() const { return map_.value_comp(); }

  iterator begin() { return map_.begin(); }
  const_iterator begin() const { return map_.begin(); }
  iterator end() { return map_.end(); }
  const_iterator end() const { return map_.end(); }

  bool empty() const { return map_.empty(); }
  size_type size() const { return map_.size(); }

  void swap(Self& other) { map_.swap(other.map_); }
  void clear() { map_.clear(); }
  iterator erase(iterator it) { return map_.erase(it); }
  size_type erase(const K& k) { return map_.erase(k); }

  iterator find(const K& k) { return map_.find(k); }
  const_iterator find(const K& k) const { return map_.find(k); }

  iterator lower_bound(const K& k) { return map_.lower_bound(k); }
  const_iterator lower_bound(const K& k) const { return map_.lower_bound(k); }

  size_type count(const K& k) const { return map_.count(k); }

  // Note that unlike std::map's operator[], this doesn't return a reference to the value.
  V Get(const K& k) const {
    const_iterator it = map_.find(k);
    DCHECK(it != map_.end());
    return it->second;
  }

  // Used to insert a new mapping.
  iterator Put(const K& k, const V& v) {
    std::pair<iterator, bool> result = map_.emplace(k, v);
    DCHECK(result.second);  // Check we didn't accidentally overwrite an existing value.
    return result.first;
  }

  // Used to insert a new mapping at a known position for better performance.
  iterator PutBefore(iterator pos, const K& k, const V& v) {
    // Check that we're using the correct position and the key is not in the map.
    DCHECK(pos == map_.end() || map_.key_comp()(k, pos->first));
    DCHECK(pos == map_.begin() || map_.key_comp()((--iterator(pos))->first, k));
    return map_.emplace_hint(pos, k, v);
  }

  // Used to insert a new mapping or overwrite an existing mapping. Note that if the value type
  // of this container is a pointer, any overwritten pointer will be lost and if this container
  // was the owner, you have a leak.
  void Overwrite(const K& k, const V& v) {
    std::pair<iterator, bool> result = map_.insert(std::make_pair(k, v));
    if (!result.second) {
      // Already there - update the value for the existing key
      result.first->second = v;
    }
  }

  bool Equals(const Self& rhs) const {
    return map_ == rhs.map_;
  }

 private:
  ::std::map<K, V, Comparator, Allocator> map_;
};

template <typename K, typename V, typename Comparator, typename Allocator>
bool operator==(const SafeMap<K, V, Comparator, Allocator>& lhs,
                const SafeMap<K, V, Comparator, Allocator>& rhs) {
  return lhs.Equals(rhs);
}

template <typename K, typename V, typename Comparator, typename Allocator>
bool operator!=(const SafeMap<K, V, Comparator, Allocator>& lhs,
                const SafeMap<K, V, Comparator, Allocator>& rhs) {
  return !(lhs == rhs);
}

template<class Key, class T, AllocatorTag kTag, class Compare = std::less<Key>>
class AllocationTrackingSafeMap : public SafeMap<
    Key, T, Compare, TrackingAllocator<std::pair<Key, T>, kTag>> {
};

}  // namespace art

#endif  // ART_RUNTIME_SAFE_MAP_H_