1/*
2 * Copyright (c) 2000-2001 Apple Computer, Inc. All Rights Reserved.
3 *
4 * The contents of this file constitute Original Code as defined in and are
5 * subject to the Apple Public Source License Version 1.2 (the 'License').
6 * You may not use this file except in compliance with the License. Please obtain
7 * a copy of the License at http://www.apple.com/publicsource and read it before
8 * using this file.
9 *
10 * This Original Code and all software distributed under the License are
11 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS
12 * OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, INCLUDING WITHOUT
13 * LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
14 * PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. Please see the License for the
15 * specific language governing rights and limitations under the License.
16 */
17
18
19/*
20 * LockedMap.h - STL-style map with attached Mutex
21 *
22 * Created 9/1/2000 by Doug Mitchell.
23 * Copyright (c) 2000 by Apple Computer.
24 */
25
26#ifndef	_LOCKED_MAP_H_
27#define _LOCKED_MAP_H_
28
29#include <map>
30#include <security_utilities/threading.h>
31
32template <class KeyType, class ValueType>
33class LockedMap
34{
35private:
36	typedef std::map<KeyType, ValueType *> MapType;
37	MapType					mMap;
38	Mutex					mMapLock;
39
40	/* low-level lookup, cacheMapLock held on entry and exit */
41	ValueType
42	*lookupEntryLocked(KeyType key)
43		{
44			// don't create new entry if desired entry isn't there
45			typename MapType::iterator it = mMap.find(key);
46			if(it == mMap.end()) {
47				return NULL;
48			}
49			return it->second;
50		}
51
52public:
53	/* high level maintenance */
54	void
55	addEntry(ValueType &value, KeyType key)
56		{
57			StLock<Mutex> _(mMapLock);
58			mMap[key] = &value;
59		}
60
61	ValueType
62	*lookupEntry(KeyType key)
63		{
64			StLock<Mutex> _(mMapLock);
65			return lookupEntryLocked(key);
66		}
67
68	void
69	removeEntry(KeyType key)
70		{
71			StLock<Mutex> _(mMapLock);
72
73			ValueType *value = lookupEntryLocked(key);
74			if(value != NULL) {
75				mMap.erase(key);
76			}
77		}
78
79	ValueType
80	*removeFirstEntry()
81		{
82			StLock<Mutex> _(mMapLock);
83			typename MapType::iterator it = mMap.begin();
84			if(it == mMap.end()) {
85				return NULL;
86			}
87			ValueType *rtn = it->second;
88			mMap.erase(it->first);
89			return rtn;
90		}
91};
92
93#endif	/* _LOCKED_MAP_H_ */
94