root/trunk/dep/src/zthread/vanilla/SimpleRecursiveLock.h

Revision 2, 2.9 kB (checked in by yumileroy, 17 years ago)

[svn] * Proper SVN structure

Original author: Neo2003
Date: 2008-10-02 16:23:55-05:00
Line 
1/*
2 * Copyright (c) 2005, Eric Crahen
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a copy
5 * of this software and associated documentation files (the "Software"), to deal
6 * in the Software without restriction, including without limitation the rights
7 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
8 * copies of the Software, and to permit persons to whom the Software is furnished
9 * to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice shall be included in all
12 * copies or substantial portions of the Software.
13 *
14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
17 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
18 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
19 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
20 *
21 */
22
23#ifndef __ZTFASTRECURSIVELOCK_H__
24#define __ZTFASTRECURSIVELOCK_H__
25
26#include "../FastLock.h"
27#include "../ThreadOps.h"
28#include <assert.h>
29
30namespace ZThread {
31
32/**
33 * @class FastRecursiveLock
34 *
35 * @author Eric Crahen <http://www.code-foo.com>
36 * @date <2003-07-16T23:30:59-0400>
37 * @version 2.2.8
38 *
39 * This implementation of a FastRecursiveLock uses the which ever FastLock
40 * that is selected to create a recursive spin lock.
41 */ 
42class FastRecursiveLock : private NonCopyable {
43 
44  FastLock _lock;
45
46  ThreadOps _owner;
47
48  volatile unsigned int _count;
49 
50public:
51 
52  inline FastRecursiveLock() : _owner(ThreadOps::INVALID), _count(0) {}
53 
54  inline ~FastRecursiveLock() {
55
56    assert(_owner == ThreadOps::INVALID);
57    assert(_count == 0);
58
59  }
60 
61  inline void acquire() {
62
63    ThreadOps self(ThreadOps::self());
64    bool wasLocked = false;
65
66    do {
67     
68      _lock.acquire();
69     
70      // If there is no owner, or the owner is the caller
71      // update the count
72      if(_owner == ThreadOps::INVALID || _owner == self) {
73
74        _owner = self;
75        _count++;
76       
77        wasLocked = true;
78 
79      }
80
81      _lock.release();
82     
83    } while(!wasLocked);
84
85    assert(_owner == ThreadOps::self());
86
87  }
88
89  inline void release() {
90
91    assert(_owner == ThreadOps::self());
92
93    _lock.acquire();
94
95    if(--_count == 0)
96      _owner = ThreadOps::INVALID;
97
98    _lock.release();
99   
100  }
101 
102  inline bool tryAcquire(unsigned long timeout=0) {
103
104    ThreadOps self(ThreadOps::self());
105    bool wasLocked = false;
106
107    _lock.acquire();
108   
109    if(_owner == ThreadOps::INVALID || _owner == self) {
110   
111      _owner = self;
112      _count++;
113     
114      wasLocked = true;
115
116    }
117   
118    _lock.release();
119
120    assert(!wasLocked || _owner == ThreadOps::self());
121    return wasLocked;   
122   
123  }
124 
125}; /* FastRecursiveLock */
126
127
128} // namespace ZThread
129
130#endif
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