1 /* $Id: token.c,v 1.1 2008/09/24 22:40:30 fredette Exp $ */
2
3 /* libtme/token.c - token functions: */
4
5 /*
6 * Copyright (c) 2008 Matt Fredette
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. All advertising materials mentioning features or use of this software
18 * must display the following acknowledgement:
19 * This product includes software developed by Matt Fredette.
20 * 4. The name of the author may not be used to endorse or promote products
21 * derived from this software without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
25 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
26 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
27 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
28 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
29 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
31 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
32 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
33 * POSSIBILITY OF SUCH DAMAGE.
34 */
35
36 #include <tme/common.h>
37 _TME_RCSID("$Id: token.c,v 1.1 2008/09/24 22:40:30 fredette Exp $");
38
39 /* includes: */
40 #include <tme/token.h>
41
42 /* this initializes a token: */
43 void
tme_token_init(struct tme_token * token)44 tme_token_init(struct tme_token *token)
45 {
46
47 /* a constructed token is invalid: */
48 tme_memory_atomic_init_flag(&token->tme_token_invalid, TRUE);
49
50 #if !TME_THREADS_COOPERATIVE || !defined(TME_NO_DEBUG_LOCKS)
51
52 /* a constructed token is not busy: */
53 tme_memory_atomic_init_flag(&token->tme_token_busy, FALSE);
54
55 /* initialize the token's invalid mutex: */
56 tme_mutex_init(&token->tme_token_invalid_mutex);
57
58 #ifndef TME_NO_DEBUG_LOCKS
59
60 /* initialize the file and line number of the last busier or
61 unbusier: */
62 token->_tme_token_busy_file = NULL;
63 token->_tme_token_busy_line = 0;
64
65 #endif /* !TME_NO_DEBUG_LOCKS */
66
67 #endif /* !TME_THREADS_COOPERATIVE || !defined(TME_NO_DEBUG_LOCKS) */
68 }
69
70 /* this invalidates a token: */
71 void
tme_token_invalidate(struct tme_token * token)72 tme_token_invalidate(struct tme_token *token)
73 {
74
75 #if !TME_THREADS_COOPERATIVE || !defined(TME_NO_DEBUG_LOCKS)
76
77 /* lock the token's invalid mutex: */
78 tme_mutex_lock(&token->tme_token_invalid_mutex);
79
80 #endif /* !TME_THREADS_COOPERATIVE || !defined(TME_NO_DEBUG_LOCKS) */
81
82 /* invalidate the token: */
83 tme_memory_atomic_write_flag(&token->tme_token_invalid, TRUE);
84
85 #if TME_THREADS_COOPERATIVE
86 #ifndef TME_NO_DEBUG_LOCKS
87
88 /* this token must not be busy: */
89 assert (!tme_memory_atomic_read_flag(&token->tme_token_busy));
90
91 #endif /* !TME_NO_DEBUG_LOCKS */
92 #else /* !TME_THREADS_COOPERATIVE */
93
94 /* spin while the token is busy: */
95 do { } while(tme_memory_atomic_read_flag(&token->tme_token_busy));
96
97 #endif /* !TME_THREADS_COOPERATIVE */
98
99 #if !TME_THREADS_COOPERATIVE || !defined(TME_NO_DEBUG_LOCKS)
100
101 /* unlock the token's invalid mutex: */
102 tme_mutex_unlock(&token->tme_token_invalid_mutex);
103
104 #endif /* !TME_THREADS_COOPERATIVE || !defined(TME_NO_DEBUG_LOCKS) */
105 }
106
107 /* this clears an invalid token: */
108 #undef tme_token_invalid_clear
109 void
tme_token_invalid_clear(struct tme_token * token)110 tme_token_invalid_clear(struct tme_token *token)
111 {
112
113 #if !TME_THREADS_COOPERATIVE || !defined(TME_NO_DEBUG_LOCKS)
114
115 /* the token must not be busy: */
116 assert (!tme_memory_atomic_read_flag(&token->tme_token_busy));
117
118 #endif /* !TME_THREADS_COOPERATIVE || !defined(TME_NO_DEBUG_LOCKS) */
119
120 /* if the token is valid, return now: */
121 if (__tme_predict_false(!tme_memory_atomic_read_flag(&(token)->tme_token_invalid))) {
122 return;
123 }
124
125 #if !TME_THREADS_COOPERATIVE || !defined(TME_NO_DEBUG_LOCKS)
126
127 /* lock the token's invalid mutex: */
128 tme_mutex_lock(&token->tme_token_invalid_mutex);
129
130 #endif /* !TME_THREADS_COOPERATIVE || !defined(TME_NO_DEBUG_LOCKS) */
131
132 /* mark the token as valid again: */
133 tme_memory_atomic_write_flag(&token->tme_token_invalid, FALSE);
134
135 #if !TME_THREADS_COOPERATIVE || !defined(TME_NO_DEBUG_LOCKS)
136
137 /* unlock the token's invalid mutex: */
138 tme_mutex_unlock(&token->tme_token_invalid_mutex);
139
140 #endif /* !TME_THREADS_COOPERATIVE || !defined(TME_NO_DEBUG_LOCKS) */
141 }
142