ipc/chromium/src/base/id_map.h@6474c204b198 (annotated)
ipc/chromium/src/base/id_map.h
Wed, 31 Dec 2014 06:09:35 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Wed, 31 Dec 2014 06:09:35 +0100
- changeset 0
- 6474c204b198
- permissions
- -rw-r--r--
Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.
| michael@0 | 1 | // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved. |
| michael@0 | 2 | // Use of this source code is governed by a BSD-style license that can be |
| michael@0 | 3 | // found in the LICENSE file. |
| michael@0 | 4 | |
| michael@0 | 5 | #ifndef BASE_ID_MAP_H__ |
| michael@0 | 6 | #define BASE_ID_MAP_H__ |
| michael@0 | 7 | |
| michael@0 | 8 | #include "base/basictypes.h" |
| michael@0 | 9 | #include "base/hash_tables.h" |
| michael@0 | 10 | #include "base/logging.h" |
| michael@0 | 11 | |
| michael@0 | 12 | // This object maintains a list of IDs that can be quickly converted to |
| michael@0 | 13 | // pointers to objects. It is implemented as a hash table, optimized for |
| michael@0 | 14 | // relatively small data sets (in the common case, there will be exactly one |
| michael@0 | 15 | // item in the list). |
| michael@0 | 16 | // |
| michael@0 | 17 | // Items can be inserted into the container with arbitrary ID, but the caller |
| michael@0 | 18 | // must ensure they are unique. Inserting IDs and relying on automatically |
| michael@0 | 19 | // generated ones is not allowed because they can collide. |
| michael@0 | 20 | template<class T> |
| michael@0 | 21 | class IDMap { |
| michael@0 | 22 | private: |
| michael@0 | 23 | typedef base::hash_map<int32_t, T*> HashTable; |
| michael@0 | 24 | typedef typename HashTable::iterator iterator; |
| michael@0 | 25 | |
| michael@0 | 26 | public: |
| michael@0 | 27 | // support const iterators over the items |
| michael@0 | 28 | // Note, use iterator->first to get the ID, iterator->second to get the T* |
| michael@0 | 29 | typedef typename HashTable::const_iterator const_iterator; |
| michael@0 | 30 | |
| michael@0 | 31 | IDMap() : next_id_(1) { |
| michael@0 | 32 | } |
| michael@0 | 33 | IDMap(const IDMap& other) : next_id_(other.next_id_), |
| michael@0 | 34 | data_(other.data_) { |
| michael@0 | 35 | } |
| michael@0 | 36 | |
| michael@0 | 37 | const_iterator begin() const { |
| michael@0 | 38 | return data_.begin(); |
| michael@0 | 39 | } |
| michael@0 | 40 | const_iterator end() const { |
| michael@0 | 41 | return data_.end(); |
| michael@0 | 42 | } |
| michael@0 | 43 | |
| michael@0 | 44 | // Adds a view with an automatically generated unique ID. See AddWithID. |
| michael@0 | 45 | int32_t Add(T* data) { |
| michael@0 | 46 | int32_t this_id = next_id_; |
| michael@0 | 47 | DCHECK(data_.find(this_id) == data_.end()) << "Inserting duplicate item"; |
| michael@0 | 48 | data_[this_id] = data; |
| michael@0 | 49 | next_id_++; |
| michael@0 | 50 | return this_id; |
| michael@0 | 51 | } |
| michael@0 | 52 | |
| michael@0 | 53 | // Adds a new data member with the specified ID. The ID must not be in |
| michael@0 | 54 | // the list. The caller either must generate all unique IDs itself and use |
| michael@0 | 55 | // this function, or allow this object to generate IDs and call Add. These |
| michael@0 | 56 | // two methods may not be mixed, or duplicate IDs may be generated |
| michael@0 | 57 | void AddWithID(T* data, int32_t id) { |
| michael@0 | 58 | DCHECK(data_.find(id) == data_.end()) << "Inserting duplicate item"; |
| michael@0 | 59 | data_[id] = data; |
| michael@0 | 60 | } |
| michael@0 | 61 | |
| michael@0 | 62 | void Remove(int32_t id) { |
| michael@0 | 63 | iterator i = data_.find(id); |
| michael@0 | 64 | if (i == data_.end()) { |
| michael@0 | 65 | NOTREACHED() << "Attempting to remove an item not in the list"; |
| michael@0 | 66 | return; |
| michael@0 | 67 | } |
| michael@0 | 68 | data_.erase(i); |
| michael@0 | 69 | } |
| michael@0 | 70 | |
| michael@0 | 71 | bool IsEmpty() const { |
| michael@0 | 72 | return data_.empty(); |
| michael@0 | 73 | } |
| michael@0 | 74 | |
| michael@0 | 75 | void Clear() { |
| michael@0 | 76 | data_.clear(); |
| michael@0 | 77 | } |
| michael@0 | 78 | |
| michael@0 | 79 | bool HasData(const T* data) const { |
| michael@0 | 80 | // XXX would like to use <algorithm> here ... |
| michael@0 | 81 | for (const_iterator it = begin(); it != end(); ++it) |
| michael@0 | 82 | if (data == it->second) |
| michael@0 | 83 | return true; |
| michael@0 | 84 | return false; |
| michael@0 | 85 | } |
| michael@0 | 86 | |
| michael@0 | 87 | T* Lookup(int32_t id) const { |
| michael@0 | 88 | const_iterator i = data_.find(id); |
| michael@0 | 89 | if (i == data_.end()) |
| michael@0 | 90 | return NULL; |
| michael@0 | 91 | return i->second; |
| michael@0 | 92 | } |
| michael@0 | 93 | |
| michael@0 | 94 | size_t size() const { |
| michael@0 | 95 | return data_.size(); |
| michael@0 | 96 | } |
| michael@0 | 97 | |
| michael@0 | 98 | protected: |
| michael@0 | 99 | // The next ID that we will return from Add() |
| michael@0 | 100 | int32_t next_id_; |
| michael@0 | 101 | |
| michael@0 | 102 | HashTable data_; |
| michael@0 | 103 | }; |
| michael@0 | 104 | |
| michael@0 | 105 | #endif // BASE_ID_MAP_H__ |
