| 1 | /* Locking in multithreaded situations.
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| 2 | Copyright (C) 2005-2012 Free Software Foundation, Inc.
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| 3 |
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| 4 | This program is free software; you can redistribute it and/or modify
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| 5 | it under the terms of the GNU General Public License as published by
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| 6 | the Free Software Foundation; either version 3, or (at your option)
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| 7 | any later version.
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| 8 |
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| 9 | This program is distributed in the hope that it will be useful,
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| 10 | but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 12 | GNU General Public License for more details.
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| 13 |
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| 14 | You should have received a copy of the GNU General Public License
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| 15 | along with this program; if not, see <http://www.gnu.org/licenses/>. */
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| 16 |
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| 17 | /* Written by Bruno Haible <bruno@clisp.org>, 2005.
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| 18 | Based on GCC's gthr-posix.h, gthr-posix95.h, gthr-solaris.h,
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| 19 | gthr-win32.h. */
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| 20 |
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| 21 | #include <config.h>
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| 22 |
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| 23 | #include "glthread/lock.h"
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| 24 |
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| 25 | /* ========================================================================= */
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| 26 |
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| 27 | #if USE_POSIX_THREADS
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| 28 |
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| 29 | /* -------------------------- gl_lock_t datatype -------------------------- */
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| 30 |
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| 31 | /* ------------------------- gl_rwlock_t datatype ------------------------- */
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| 32 |
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| 33 | # if HAVE_PTHREAD_RWLOCK
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| 34 |
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| 35 | # if !defined PTHREAD_RWLOCK_INITIALIZER
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| 36 |
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| 37 | int
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| 38 | glthread_rwlock_init_multithreaded (gl_rwlock_t *lock)
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| 39 | {
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| 40 | int err;
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| 41 |
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| 42 | err = pthread_rwlock_init (&lock->rwlock, NULL);
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| 43 | if (err != 0)
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| 44 | return err;
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| 45 | lock->initialized = 1;
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| 46 | return 0;
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| 47 | }
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| 48 |
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| 49 | int
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| 50 | glthread_rwlock_rdlock_multithreaded (gl_rwlock_t *lock)
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| 51 | {
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| 52 | if (!lock->initialized)
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| 53 | {
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| 54 | int err;
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| 55 |
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| 56 | err = pthread_mutex_lock (&lock->guard);
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| 57 | if (err != 0)
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| 58 | return err;
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| 59 | if (!lock->initialized)
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| 60 | {
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| 61 | err = glthread_rwlock_init_multithreaded (lock);
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| 62 | if (err != 0)
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| 63 | {
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| 64 | pthread_mutex_unlock (&lock->guard);
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| 65 | return err;
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| 66 | }
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| 67 | }
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| 68 | err = pthread_mutex_unlock (&lock->guard);
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| 69 | if (err != 0)
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| 70 | return err;
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| 71 | }
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| 72 | return pthread_rwlock_rdlock (&lock->rwlock);
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| 73 | }
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| 74 |
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| 75 | int
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| 76 | glthread_rwlock_wrlock_multithreaded (gl_rwlock_t *lock)
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| 77 | {
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| 78 | if (!lock->initialized)
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| 79 | {
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| 80 | int err;
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| 81 |
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| 82 | err = pthread_mutex_lock (&lock->guard);
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| 83 | if (err != 0)
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| 84 | return err;
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| 85 | if (!lock->initialized)
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| 86 | {
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| 87 | err = glthread_rwlock_init_multithreaded (lock);
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| 88 | if (err != 0)
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| 89 | {
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| 90 | pthread_mutex_unlock (&lock->guard);
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| 91 | return err;
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| 92 | }
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| 93 | }
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| 94 | err = pthread_mutex_unlock (&lock->guard);
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| 95 | if (err != 0)
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| 96 | return err;
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| 97 | }
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| 98 | return pthread_rwlock_wrlock (&lock->rwlock);
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| 99 | }
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| 100 |
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| 101 | int
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| 102 | glthread_rwlock_unlock_multithreaded (gl_rwlock_t *lock)
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| 103 | {
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| 104 | if (!lock->initialized)
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| 105 | return EINVAL;
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| 106 | return pthread_rwlock_unlock (&lock->rwlock);
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| 107 | }
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| 108 |
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| 109 | int
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| 110 | glthread_rwlock_destroy_multithreaded (gl_rwlock_t *lock)
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| 111 | {
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| 112 | int err;
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| 113 |
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| 114 | if (!lock->initialized)
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| 115 | return EINVAL;
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| 116 | err = pthread_rwlock_destroy (&lock->rwlock);
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| 117 | if (err != 0)
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| 118 | return err;
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| 119 | lock->initialized = 0;
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| 120 | return 0;
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| 121 | }
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| 122 |
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| 123 | # endif
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| 124 |
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| 125 | # else
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| 126 |
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| 127 | int
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| 128 | glthread_rwlock_init_multithreaded (gl_rwlock_t *lock)
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| 129 | {
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| 130 | int err;
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| 131 |
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| 132 | err = pthread_mutex_init (&lock->lock, NULL);
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| 133 | if (err != 0)
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| 134 | return err;
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| 135 | err = pthread_cond_init (&lock->waiting_readers, NULL);
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| 136 | if (err != 0)
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| 137 | return err;
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| 138 | err = pthread_cond_init (&lock->waiting_writers, NULL);
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| 139 | if (err != 0)
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| 140 | return err;
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| 141 | lock->waiting_writers_count = 0;
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| 142 | lock->runcount = 0;
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| 143 | return 0;
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| 144 | }
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| 145 |
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| 146 | int
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| 147 | glthread_rwlock_rdlock_multithreaded (gl_rwlock_t *lock)
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| 148 | {
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| 149 | int err;
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| 150 |
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| 151 | err = pthread_mutex_lock (&lock->lock);
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| 152 | if (err != 0)
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| 153 | return err;
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| 154 | /* Test whether only readers are currently running, and whether the runcount
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| 155 | field will not overflow. */
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| 156 | /* POSIX says: "It is implementation-defined whether the calling thread
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| 157 | acquires the lock when a writer does not hold the lock and there are
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| 158 | writers blocked on the lock." Let's say, no: give the writers a higher
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| 159 | priority. */
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| 160 | while (!(lock->runcount + 1 > 0 && lock->waiting_writers_count == 0))
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| 161 | {
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| 162 | /* This thread has to wait for a while. Enqueue it among the
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| 163 | waiting_readers. */
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| 164 | err = pthread_cond_wait (&lock->waiting_readers, &lock->lock);
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| 165 | if (err != 0)
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| 166 | {
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| 167 | pthread_mutex_unlock (&lock->lock);
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| 168 | return err;
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| 169 | }
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| 170 | }
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| 171 | lock->runcount++;
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| 172 | return pthread_mutex_unlock (&lock->lock);
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| 173 | }
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| 174 |
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| 175 | int
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| 176 | glthread_rwlock_wrlock_multithreaded (gl_rwlock_t *lock)
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| 177 | {
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| 178 | int err;
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| 179 |
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| 180 | err = pthread_mutex_lock (&lock->lock);
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| 181 | if (err != 0)
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| 182 | return err;
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| 183 | /* Test whether no readers or writers are currently running. */
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| 184 | while (!(lock->runcount == 0))
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| 185 | {
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| 186 | /* This thread has to wait for a while. Enqueue it among the
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| 187 | waiting_writers. */
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| 188 | lock->waiting_writers_count++;
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| 189 | err = pthread_cond_wait (&lock->waiting_writers, &lock->lock);
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| 190 | if (err != 0)
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| 191 | {
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| 192 | lock->waiting_writers_count--;
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| 193 | pthread_mutex_unlock (&lock->lock);
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| 194 | return err;
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| 195 | }
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| 196 | lock->waiting_writers_count--;
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| 197 | }
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| 198 | lock->runcount--; /* runcount becomes -1 */
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| 199 | return pthread_mutex_unlock (&lock->lock);
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| 200 | }
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| 201 |
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| 202 | int
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| 203 | glthread_rwlock_unlock_multithreaded (gl_rwlock_t *lock)
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| 204 | {
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| 205 | int err;
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| 206 |
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| 207 | err = pthread_mutex_lock (&lock->lock);
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| 208 | if (err != 0)
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| 209 | return err;
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| 210 | if (lock->runcount < 0)
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| 211 | {
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| 212 | /* Drop a writer lock. */
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| 213 | if (!(lock->runcount == -1))
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| 214 | {
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| 215 | pthread_mutex_unlock (&lock->lock);
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| 216 | return EINVAL;
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| 217 | }
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| 218 | lock->runcount = 0;
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| 219 | }
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| 220 | else
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| 221 | {
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| 222 | /* Drop a reader lock. */
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| 223 | if (!(lock->runcount > 0))
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| 224 | {
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| 225 | pthread_mutex_unlock (&lock->lock);
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| 226 | return EINVAL;
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| 227 | }
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| 228 | lock->runcount--;
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| 229 | }
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| 230 | if (lock->runcount == 0)
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| 231 | {
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| 232 | /* POSIX recommends that "write locks shall take precedence over read
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| 233 | locks", to avoid "writer starvation". */
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| 234 | if (lock->waiting_writers_count > 0)
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| 235 | {
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| 236 | /* Wake up one of the waiting writers. */
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| 237 | err = pthread_cond_signal (&lock->waiting_writers);
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| 238 | if (err != 0)
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| 239 | {
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| 240 | pthread_mutex_unlock (&lock->lock);
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| 241 | return err;
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| 242 | }
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| 243 | }
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| 244 | else
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| 245 | {
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| 246 | /* Wake up all waiting readers. */
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| 247 | err = pthread_cond_broadcast (&lock->waiting_readers);
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| 248 | if (err != 0)
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| 249 | {
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| 250 | pthread_mutex_unlock (&lock->lock);
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| 251 | return err;
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| 252 | }
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| 253 | }
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| 254 | }
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| 255 | return pthread_mutex_unlock (&lock->lock);
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| 256 | }
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| 257 |
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| 258 | int
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| 259 | glthread_rwlock_destroy_multithreaded (gl_rwlock_t *lock)
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| 260 | {
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| 261 | int err;
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| 262 |
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| 263 | err = pthread_mutex_destroy (&lock->lock);
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| 264 | if (err != 0)
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| 265 | return err;
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| 266 | err = pthread_cond_destroy (&lock->waiting_readers);
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| 267 | if (err != 0)
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| 268 | return err;
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| 269 | err = pthread_cond_destroy (&lock->waiting_writers);
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| 270 | if (err != 0)
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| 271 | return err;
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| 272 | return 0;
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| 273 | }
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| 274 |
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| 275 | # endif
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| 276 |
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| 277 | /* --------------------- gl_recursive_lock_t datatype --------------------- */
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| 278 |
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| 279 | # if HAVE_PTHREAD_MUTEX_RECURSIVE
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| 280 |
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| 281 | # if defined PTHREAD_RECURSIVE_MUTEX_INITIALIZER || defined PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP
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| 282 |
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| 283 | int
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| 284 | glthread_recursive_lock_init_multithreaded (gl_recursive_lock_t *lock)
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| 285 | {
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| 286 | pthread_mutexattr_t attributes;
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| 287 | int err;
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| 288 |
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| 289 | err = pthread_mutexattr_init (&attributes);
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| 290 | if (err != 0)
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| 291 | return err;
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| 292 | err = pthread_mutexattr_settype (&attributes, PTHREAD_MUTEX_RECURSIVE);
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| 293 | if (err != 0)
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| 294 | {
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| 295 | pthread_mutexattr_destroy (&attributes);
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| 296 | return err;
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| 297 | }
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| 298 | err = pthread_mutex_init (lock, &attributes);
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| 299 | if (err != 0)
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| 300 | {
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| 301 | pthread_mutexattr_destroy (&attributes);
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| 302 | return err;
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| 303 | }
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| 304 | err = pthread_mutexattr_destroy (&attributes);
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| 305 | if (err != 0)
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| 306 | return err;
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| 307 | return 0;
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| 308 | }
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| 309 |
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| 310 | # else
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| 311 |
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| 312 | int
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| 313 | glthread_recursive_lock_init_multithreaded (gl_recursive_lock_t *lock)
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| 314 | {
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| 315 | pthread_mutexattr_t attributes;
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| 316 | int err;
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| 317 |
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| 318 | err = pthread_mutexattr_init (&attributes);
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| 319 | if (err != 0)
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| 320 | return err;
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| 321 | err = pthread_mutexattr_settype (&attributes, PTHREAD_MUTEX_RECURSIVE);
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| 322 | if (err != 0)
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| 323 | {
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| 324 | pthread_mutexattr_destroy (&attributes);
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| 325 | return err;
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| 326 | }
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| 327 | err = pthread_mutex_init (&lock->recmutex, &attributes);
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| 328 | if (err != 0)
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| 329 | {
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| 330 | pthread_mutexattr_destroy (&attributes);
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| 331 | return err;
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| 332 | }
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| 333 | err = pthread_mutexattr_destroy (&attributes);
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| 334 | if (err != 0)
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| 335 | return err;
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| 336 | lock->initialized = 1;
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| 337 | return 0;
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| 338 | }
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| 339 |
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| 340 | int
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| 341 | glthread_recursive_lock_lock_multithreaded (gl_recursive_lock_t *lock)
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| 342 | {
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| 343 | if (!lock->initialized)
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| 344 | {
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| 345 | int err;
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| 346 |
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| 347 | err = pthread_mutex_lock (&lock->guard);
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| 348 | if (err != 0)
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| 349 | return err;
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| 350 | if (!lock->initialized)
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| 351 | {
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| 352 | err = glthread_recursive_lock_init_multithreaded (lock);
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| 353 | if (err != 0)
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| 354 | {
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| 355 | pthread_mutex_unlock (&lock->guard);
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| 356 | return err;
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| 357 | }
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| 358 | }
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| 359 | err = pthread_mutex_unlock (&lock->guard);
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| 360 | if (err != 0)
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| 361 | return err;
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| 362 | }
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| 363 | return pthread_mutex_lock (&lock->recmutex);
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| 364 | }
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| 365 |
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| 366 | int
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| 367 | glthread_recursive_lock_unlock_multithreaded (gl_recursive_lock_t *lock)
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| 368 | {
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| 369 | if (!lock->initialized)
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| 370 | return EINVAL;
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| 371 | return pthread_mutex_unlock (&lock->recmutex);
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| 372 | }
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| 373 |
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| 374 | int
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| 375 | glthread_recursive_lock_destroy_multithreaded (gl_recursive_lock_t *lock)
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| 376 | {
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| 377 | int err;
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| 378 |
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| 379 | if (!lock->initialized)
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| 380 | return EINVAL;
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| 381 | err = pthread_mutex_destroy (&lock->recmutex);
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| 382 | if (err != 0)
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| 383 | return err;
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| 384 | lock->initialized = 0;
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| 385 | return 0;
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| 386 | }
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| 387 |
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| 388 | # endif
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| 389 |
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| 390 | # else
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| 391 |
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| 392 | int
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| 393 | glthread_recursive_lock_init_multithreaded (gl_recursive_lock_t *lock)
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| 394 | {
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| 395 | int err;
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| 396 |
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| 397 | err = pthread_mutex_init (&lock->mutex, NULL);
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| 398 | if (err != 0)
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| 399 | return err;
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| 400 | lock->owner = (pthread_t) 0;
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| 401 | lock->depth = 0;
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| 402 | return 0;
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| 403 | }
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| 404 |
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| 405 | int
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| 406 | glthread_recursive_lock_lock_multithreaded (gl_recursive_lock_t *lock)
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| 407 | {
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| 408 | pthread_t self = pthread_self ();
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| 409 | if (lock->owner != self)
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| 410 | {
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| 411 | int err;
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| 412 |
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| 413 | err = pthread_mutex_lock (&lock->mutex);
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| 414 | if (err != 0)
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| 415 | return err;
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| 416 | lock->owner = self;
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| 417 | }
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| 418 | if (++(lock->depth) == 0) /* wraparound? */
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| 419 | {
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| 420 | lock->depth--;
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| 421 | return EAGAIN;
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| 422 | }
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| 423 | return 0;
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| 424 | }
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| 425 |
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| 426 | int
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| 427 | glthread_recursive_lock_unlock_multithreaded (gl_recursive_lock_t *lock)
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| 428 | {
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| 429 | if (lock->owner != pthread_self ())
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| 430 | return EPERM;
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| 431 | if (lock->depth == 0)
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| 432 | return EINVAL;
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| 433 | if (--(lock->depth) == 0)
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| 434 | {
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| 435 | lock->owner = (pthread_t) 0;
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| 436 | return pthread_mutex_unlock (&lock->mutex);
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| 437 | }
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| 438 | else
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| 439 | return 0;
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| 440 | }
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| 441 |
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| 442 | int
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| 443 | glthread_recursive_lock_destroy_multithreaded (gl_recursive_lock_t *lock)
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| 444 | {
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| 445 | if (lock->owner != (pthread_t) 0)
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| 446 | return EBUSY;
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| 447 | return pthread_mutex_destroy (&lock->mutex);
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| 448 | }
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| 449 |
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| 450 | # endif
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| 451 |
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| 452 | /* -------------------------- gl_once_t datatype -------------------------- */
|
|---|
| 453 |
|
|---|
| 454 | static const pthread_once_t fresh_once = PTHREAD_ONCE_INIT;
|
|---|
| 455 |
|
|---|
| 456 | int
|
|---|
| 457 | glthread_once_singlethreaded (pthread_once_t *once_control)
|
|---|
| 458 | {
|
|---|
| 459 | /* We don't know whether pthread_once_t is an integer type, a floating-point
|
|---|
| 460 | type, a pointer type, or a structure type. */
|
|---|
| 461 | char *firstbyte = (char *)once_control;
|
|---|
| 462 | if (*firstbyte == *(const char *)&fresh_once)
|
|---|
| 463 | {
|
|---|
| 464 | /* First time use of once_control. Invert the first byte. */
|
|---|
| 465 | *firstbyte = ~ *(const char *)&fresh_once;
|
|---|
| 466 | return 1;
|
|---|
| 467 | }
|
|---|
| 468 | else
|
|---|
| 469 | return 0;
|
|---|
| 470 | }
|
|---|
| 471 |
|
|---|
| 472 | #endif
|
|---|
| 473 |
|
|---|
| 474 | /* ========================================================================= */
|
|---|
| 475 |
|
|---|
| 476 | #if USE_PTH_THREADS
|
|---|
| 477 |
|
|---|
| 478 | /* Use the GNU Pth threads library. */
|
|---|
| 479 |
|
|---|
| 480 | /* -------------------------- gl_lock_t datatype -------------------------- */
|
|---|
| 481 |
|
|---|
| 482 | /* ------------------------- gl_rwlock_t datatype ------------------------- */
|
|---|
| 483 |
|
|---|
| 484 | /* --------------------- gl_recursive_lock_t datatype --------------------- */
|
|---|
| 485 |
|
|---|
| 486 | /* -------------------------- gl_once_t datatype -------------------------- */
|
|---|
| 487 |
|
|---|
| 488 | static void
|
|---|
| 489 | glthread_once_call (void *arg)
|
|---|
| 490 | {
|
|---|
| 491 | void (**gl_once_temp_addr) (void) = (void (**) (void)) arg;
|
|---|
| 492 | void (*initfunction) (void) = *gl_once_temp_addr;
|
|---|
| 493 | initfunction ();
|
|---|
| 494 | }
|
|---|
| 495 |
|
|---|
| 496 | int
|
|---|
| 497 | glthread_once_multithreaded (pth_once_t *once_control, void (*initfunction) (void))
|
|---|
| 498 | {
|
|---|
| 499 | void (*temp) (void) = initfunction;
|
|---|
| 500 | return (!pth_once (once_control, glthread_once_call, &temp) ? errno : 0);
|
|---|
| 501 | }
|
|---|
| 502 |
|
|---|
| 503 | int
|
|---|
| 504 | glthread_once_singlethreaded (pth_once_t *once_control)
|
|---|
| 505 | {
|
|---|
| 506 | /* We know that pth_once_t is an integer type. */
|
|---|
| 507 | if (*once_control == PTH_ONCE_INIT)
|
|---|
| 508 | {
|
|---|
| 509 | /* First time use of once_control. Invert the marker. */
|
|---|
| 510 | *once_control = ~ PTH_ONCE_INIT;
|
|---|
| 511 | return 1;
|
|---|
| 512 | }
|
|---|
| 513 | else
|
|---|
| 514 | return 0;
|
|---|
| 515 | }
|
|---|
| 516 |
|
|---|
| 517 | #endif
|
|---|
| 518 |
|
|---|
| 519 | /* ========================================================================= */
|
|---|
| 520 |
|
|---|
| 521 | #if USE_SOLARIS_THREADS
|
|---|
| 522 |
|
|---|
| 523 | /* Use the old Solaris threads library. */
|
|---|
| 524 |
|
|---|
| 525 | /* -------------------------- gl_lock_t datatype -------------------------- */
|
|---|
| 526 |
|
|---|
| 527 | /* ------------------------- gl_rwlock_t datatype ------------------------- */
|
|---|
| 528 |
|
|---|
| 529 | /* --------------------- gl_recursive_lock_t datatype --------------------- */
|
|---|
| 530 |
|
|---|
| 531 | int
|
|---|
| 532 | glthread_recursive_lock_init_multithreaded (gl_recursive_lock_t *lock)
|
|---|
| 533 | {
|
|---|
| 534 | int err;
|
|---|
| 535 |
|
|---|
| 536 | err = mutex_init (&lock->mutex, USYNC_THREAD, NULL);
|
|---|
| 537 | if (err != 0)
|
|---|
| 538 | return err;
|
|---|
| 539 | lock->owner = (thread_t) 0;
|
|---|
| 540 | lock->depth = 0;
|
|---|
| 541 | return 0;
|
|---|
| 542 | }
|
|---|
| 543 |
|
|---|
| 544 | int
|
|---|
| 545 | glthread_recursive_lock_lock_multithreaded (gl_recursive_lock_t *lock)
|
|---|
| 546 | {
|
|---|
| 547 | thread_t self = thr_self ();
|
|---|
| 548 | if (lock->owner != self)
|
|---|
| 549 | {
|
|---|
| 550 | int err;
|
|---|
| 551 |
|
|---|
| 552 | err = mutex_lock (&lock->mutex);
|
|---|
| 553 | if (err != 0)
|
|---|
| 554 | return err;
|
|---|
| 555 | lock->owner = self;
|
|---|
| 556 | }
|
|---|
| 557 | if (++(lock->depth) == 0) /* wraparound? */
|
|---|
| 558 | {
|
|---|
| 559 | lock->depth--;
|
|---|
| 560 | return EAGAIN;
|
|---|
| 561 | }
|
|---|
| 562 | return 0;
|
|---|
| 563 | }
|
|---|
| 564 |
|
|---|
| 565 | int
|
|---|
| 566 | glthread_recursive_lock_unlock_multithreaded (gl_recursive_lock_t *lock)
|
|---|
| 567 | {
|
|---|
| 568 | if (lock->owner != thr_self ())
|
|---|
| 569 | return EPERM;
|
|---|
| 570 | if (lock->depth == 0)
|
|---|
| 571 | return EINVAL;
|
|---|
| 572 | if (--(lock->depth) == 0)
|
|---|
| 573 | {
|
|---|
| 574 | lock->owner = (thread_t) 0;
|
|---|
| 575 | return mutex_unlock (&lock->mutex);
|
|---|
| 576 | }
|
|---|
| 577 | else
|
|---|
| 578 | return 0;
|
|---|
| 579 | }
|
|---|
| 580 |
|
|---|
| 581 | int
|
|---|
| 582 | glthread_recursive_lock_destroy_multithreaded (gl_recursive_lock_t *lock)
|
|---|
| 583 | {
|
|---|
| 584 | if (lock->owner != (thread_t) 0)
|
|---|
| 585 | return EBUSY;
|
|---|
| 586 | return mutex_destroy (&lock->mutex);
|
|---|
| 587 | }
|
|---|
| 588 |
|
|---|
| 589 | /* -------------------------- gl_once_t datatype -------------------------- */
|
|---|
| 590 |
|
|---|
| 591 | int
|
|---|
| 592 | glthread_once_multithreaded (gl_once_t *once_control, void (*initfunction) (void))
|
|---|
| 593 | {
|
|---|
| 594 | if (!once_control->inited)
|
|---|
| 595 | {
|
|---|
| 596 | int err;
|
|---|
| 597 |
|
|---|
| 598 | /* Use the mutex to guarantee that if another thread is already calling
|
|---|
| 599 | the initfunction, this thread waits until it's finished. */
|
|---|
| 600 | err = mutex_lock (&once_control->mutex);
|
|---|
| 601 | if (err != 0)
|
|---|
| 602 | return err;
|
|---|
| 603 | if (!once_control->inited)
|
|---|
| 604 | {
|
|---|
| 605 | once_control->inited = 1;
|
|---|
| 606 | initfunction ();
|
|---|
| 607 | }
|
|---|
| 608 | return mutex_unlock (&once_control->mutex);
|
|---|
| 609 | }
|
|---|
| 610 | else
|
|---|
| 611 | return 0;
|
|---|
| 612 | }
|
|---|
| 613 |
|
|---|
| 614 | int
|
|---|
| 615 | glthread_once_singlethreaded (gl_once_t *once_control)
|
|---|
| 616 | {
|
|---|
| 617 | /* We know that gl_once_t contains an integer type. */
|
|---|
| 618 | if (!once_control->inited)
|
|---|
| 619 | {
|
|---|
| 620 | /* First time use of once_control. Invert the marker. */
|
|---|
| 621 | once_control->inited = ~ 0;
|
|---|
| 622 | return 1;
|
|---|
| 623 | }
|
|---|
| 624 | else
|
|---|
| 625 | return 0;
|
|---|
| 626 | }
|
|---|
| 627 |
|
|---|
| 628 | #endif
|
|---|
| 629 |
|
|---|
| 630 | /* ========================================================================= */
|
|---|
| 631 |
|
|---|
| 632 | #if USE_WINDOWS_THREADS
|
|---|
| 633 |
|
|---|
| 634 | /* -------------------------- gl_lock_t datatype -------------------------- */
|
|---|
| 635 |
|
|---|
| 636 | void
|
|---|
| 637 | glthread_lock_init_func (gl_lock_t *lock)
|
|---|
| 638 | {
|
|---|
| 639 | InitializeCriticalSection (&lock->lock);
|
|---|
| 640 | lock->guard.done = 1;
|
|---|
| 641 | }
|
|---|
| 642 |
|
|---|
| 643 | int
|
|---|
| 644 | glthread_lock_lock_func (gl_lock_t *lock)
|
|---|
| 645 | {
|
|---|
| 646 | if (!lock->guard.done)
|
|---|
| 647 | {
|
|---|
| 648 | if (InterlockedIncrement (&lock->guard.started) == 0)
|
|---|
| 649 | /* This thread is the first one to need this lock. Initialize it. */
|
|---|
| 650 | glthread_lock_init (lock);
|
|---|
| 651 | else
|
|---|
| 652 | /* Yield the CPU while waiting for another thread to finish
|
|---|
| 653 | initializing this lock. */
|
|---|
| 654 | while (!lock->guard.done)
|
|---|
| 655 | Sleep (0);
|
|---|
| 656 | }
|
|---|
| 657 | EnterCriticalSection (&lock->lock);
|
|---|
| 658 | return 0;
|
|---|
| 659 | }
|
|---|
| 660 |
|
|---|
| 661 | int
|
|---|
| 662 | glthread_lock_unlock_func (gl_lock_t *lock)
|
|---|
| 663 | {
|
|---|
| 664 | if (!lock->guard.done)
|
|---|
| 665 | return EINVAL;
|
|---|
| 666 | LeaveCriticalSection (&lock->lock);
|
|---|
| 667 | return 0;
|
|---|
| 668 | }
|
|---|
| 669 |
|
|---|
| 670 | int
|
|---|
| 671 | glthread_lock_destroy_func (gl_lock_t *lock)
|
|---|
| 672 | {
|
|---|
| 673 | if (!lock->guard.done)
|
|---|
| 674 | return EINVAL;
|
|---|
| 675 | DeleteCriticalSection (&lock->lock);
|
|---|
| 676 | lock->guard.done = 0;
|
|---|
| 677 | return 0;
|
|---|
| 678 | }
|
|---|
| 679 |
|
|---|
| 680 | /* ------------------------- gl_rwlock_t datatype ------------------------- */
|
|---|
| 681 |
|
|---|
| 682 | /* In this file, the waitqueues are implemented as circular arrays. */
|
|---|
| 683 | #define gl_waitqueue_t gl_carray_waitqueue_t
|
|---|
| 684 |
|
|---|
| 685 | static inline void
|
|---|
| 686 | gl_waitqueue_init (gl_waitqueue_t *wq)
|
|---|
| 687 | {
|
|---|
| 688 | wq->array = NULL;
|
|---|
| 689 | wq->count = 0;
|
|---|
| 690 | wq->alloc = 0;
|
|---|
| 691 | wq->offset = 0;
|
|---|
| 692 | }
|
|---|
| 693 |
|
|---|
| 694 | /* Enqueues the current thread, represented by an event, in a wait queue.
|
|---|
| 695 | Returns INVALID_HANDLE_VALUE if an allocation failure occurs. */
|
|---|
| 696 | static HANDLE
|
|---|
| 697 | gl_waitqueue_add (gl_waitqueue_t *wq)
|
|---|
| 698 | {
|
|---|
| 699 | HANDLE event;
|
|---|
| 700 | unsigned int index;
|
|---|
| 701 |
|
|---|
| 702 | if (wq->count == wq->alloc)
|
|---|
| 703 | {
|
|---|
| 704 | unsigned int new_alloc = 2 * wq->alloc + 1;
|
|---|
| 705 | HANDLE *new_array =
|
|---|
| 706 | (HANDLE *) realloc (wq->array, new_alloc * sizeof (HANDLE));
|
|---|
| 707 | if (new_array == NULL)
|
|---|
| 708 | /* No more memory. */
|
|---|
| 709 | return INVALID_HANDLE_VALUE;
|
|---|
| 710 | /* Now is a good opportunity to rotate the array so that its contents
|
|---|
| 711 | starts at offset 0. */
|
|---|
| 712 | if (wq->offset > 0)
|
|---|
| 713 | {
|
|---|
| 714 | unsigned int old_count = wq->count;
|
|---|
| 715 | unsigned int old_alloc = wq->alloc;
|
|---|
| 716 | unsigned int old_offset = wq->offset;
|
|---|
| 717 | unsigned int i;
|
|---|
| 718 | if (old_offset + old_count > old_alloc)
|
|---|
| 719 | {
|
|---|
| 720 | unsigned int limit = old_offset + old_count - old_alloc;
|
|---|
| 721 | for (i = 0; i < limit; i++)
|
|---|
| 722 | new_array[old_alloc + i] = new_array[i];
|
|---|
| 723 | }
|
|---|
| 724 | for (i = 0; i < old_count; i++)
|
|---|
| 725 | new_array[i] = new_array[old_offset + i];
|
|---|
| 726 | wq->offset = 0;
|
|---|
| 727 | }
|
|---|
| 728 | wq->array = new_array;
|
|---|
| 729 | wq->alloc = new_alloc;
|
|---|
| 730 | }
|
|---|
| 731 | /* Whether the created event is a manual-reset one or an auto-reset one,
|
|---|
| 732 | does not matter, since we will wait on it only once. */
|
|---|
| 733 | event = CreateEvent (NULL, TRUE, FALSE, NULL);
|
|---|
| 734 | if (event == INVALID_HANDLE_VALUE)
|
|---|
| 735 | /* No way to allocate an event. */
|
|---|
| 736 | return INVALID_HANDLE_VALUE;
|
|---|
| 737 | index = wq->offset + wq->count;
|
|---|
| 738 | if (index >= wq->alloc)
|
|---|
| 739 | index -= wq->alloc;
|
|---|
| 740 | wq->array[index] = event;
|
|---|
| 741 | wq->count++;
|
|---|
| 742 | return event;
|
|---|
| 743 | }
|
|---|
| 744 |
|
|---|
| 745 | /* Notifies the first thread from a wait queue and dequeues it. */
|
|---|
| 746 | static inline void
|
|---|
| 747 | gl_waitqueue_notify_first (gl_waitqueue_t *wq)
|
|---|
| 748 | {
|
|---|
| 749 | SetEvent (wq->array[wq->offset + 0]);
|
|---|
| 750 | wq->offset++;
|
|---|
| 751 | wq->count--;
|
|---|
| 752 | if (wq->count == 0 || wq->offset == wq->alloc)
|
|---|
| 753 | wq->offset = 0;
|
|---|
| 754 | }
|
|---|
| 755 |
|
|---|
| 756 | /* Notifies all threads from a wait queue and dequeues them all. */
|
|---|
| 757 | static inline void
|
|---|
| 758 | gl_waitqueue_notify_all (gl_waitqueue_t *wq)
|
|---|
| 759 | {
|
|---|
| 760 | unsigned int i;
|
|---|
| 761 |
|
|---|
| 762 | for (i = 0; i < wq->count; i++)
|
|---|
| 763 | {
|
|---|
| 764 | unsigned int index = wq->offset + i;
|
|---|
| 765 | if (index >= wq->alloc)
|
|---|
| 766 | index -= wq->alloc;
|
|---|
| 767 | SetEvent (wq->array[index]);
|
|---|
| 768 | }
|
|---|
| 769 | wq->count = 0;
|
|---|
| 770 | wq->offset = 0;
|
|---|
| 771 | }
|
|---|
| 772 |
|
|---|
| 773 | void
|
|---|
| 774 | glthread_rwlock_init_func (gl_rwlock_t *lock)
|
|---|
| 775 | {
|
|---|
| 776 | InitializeCriticalSection (&lock->lock);
|
|---|
| 777 | gl_waitqueue_init (&lock->waiting_readers);
|
|---|
| 778 | gl_waitqueue_init (&lock->waiting_writers);
|
|---|
| 779 | lock->runcount = 0;
|
|---|
| 780 | lock->guard.done = 1;
|
|---|
| 781 | }
|
|---|
| 782 |
|
|---|
| 783 | int
|
|---|
| 784 | glthread_rwlock_rdlock_func (gl_rwlock_t *lock)
|
|---|
| 785 | {
|
|---|
| 786 | if (!lock->guard.done)
|
|---|
| 787 | {
|
|---|
| 788 | if (InterlockedIncrement (&lock->guard.started) == 0)
|
|---|
| 789 | /* This thread is the first one to need this lock. Initialize it. */
|
|---|
| 790 | glthread_rwlock_init (lock);
|
|---|
| 791 | else
|
|---|
| 792 | /* Yield the CPU while waiting for another thread to finish
|
|---|
| 793 | initializing this lock. */
|
|---|
| 794 | while (!lock->guard.done)
|
|---|
| 795 | Sleep (0);
|
|---|
| 796 | }
|
|---|
| 797 | EnterCriticalSection (&lock->lock);
|
|---|
| 798 | /* Test whether only readers are currently running, and whether the runcount
|
|---|
| 799 | field will not overflow. */
|
|---|
| 800 | if (!(lock->runcount + 1 > 0))
|
|---|
| 801 | {
|
|---|
| 802 | /* This thread has to wait for a while. Enqueue it among the
|
|---|
| 803 | waiting_readers. */
|
|---|
| 804 | HANDLE event = gl_waitqueue_add (&lock->waiting_readers);
|
|---|
| 805 | if (event != INVALID_HANDLE_VALUE)
|
|---|
| 806 | {
|
|---|
| 807 | DWORD result;
|
|---|
| 808 | LeaveCriticalSection (&lock->lock);
|
|---|
| 809 | /* Wait until another thread signals this event. */
|
|---|
| 810 | result = WaitForSingleObject (event, INFINITE);
|
|---|
| 811 | if (result == WAIT_FAILED || result == WAIT_TIMEOUT)
|
|---|
| 812 | abort ();
|
|---|
| 813 | CloseHandle (event);
|
|---|
| 814 | /* The thread which signalled the event already did the bookkeeping:
|
|---|
| 815 | removed us from the waiting_readers, incremented lock->runcount. */
|
|---|
| 816 | if (!(lock->runcount > 0))
|
|---|
| 817 | abort ();
|
|---|
| 818 | return 0;
|
|---|
| 819 | }
|
|---|
| 820 | else
|
|---|
| 821 | {
|
|---|
| 822 | /* Allocation failure. Weird. */
|
|---|
| 823 | do
|
|---|
| 824 | {
|
|---|
| 825 | LeaveCriticalSection (&lock->lock);
|
|---|
| 826 | Sleep (1);
|
|---|
| 827 | EnterCriticalSection (&lock->lock);
|
|---|
| 828 | }
|
|---|
| 829 | while (!(lock->runcount + 1 > 0));
|
|---|
| 830 | }
|
|---|
| 831 | }
|
|---|
| 832 | lock->runcount++;
|
|---|
| 833 | LeaveCriticalSection (&lock->lock);
|
|---|
| 834 | return 0;
|
|---|
| 835 | }
|
|---|
| 836 |
|
|---|
| 837 | int
|
|---|
| 838 | glthread_rwlock_wrlock_func (gl_rwlock_t *lock)
|
|---|
| 839 | {
|
|---|
| 840 | if (!lock->guard.done)
|
|---|
| 841 | {
|
|---|
| 842 | if (InterlockedIncrement (&lock->guard.started) == 0)
|
|---|
| 843 | /* This thread is the first one to need this lock. Initialize it. */
|
|---|
| 844 | glthread_rwlock_init (lock);
|
|---|
| 845 | else
|
|---|
| 846 | /* Yield the CPU while waiting for another thread to finish
|
|---|
| 847 | initializing this lock. */
|
|---|
| 848 | while (!lock->guard.done)
|
|---|
| 849 | Sleep (0);
|
|---|
| 850 | }
|
|---|
| 851 | EnterCriticalSection (&lock->lock);
|
|---|
| 852 | /* Test whether no readers or writers are currently running. */
|
|---|
| 853 | if (!(lock->runcount == 0))
|
|---|
| 854 | {
|
|---|
| 855 | /* This thread has to wait for a while. Enqueue it among the
|
|---|
| 856 | waiting_writers. */
|
|---|
| 857 | HANDLE event = gl_waitqueue_add (&lock->waiting_writers);
|
|---|
| 858 | if (event != INVALID_HANDLE_VALUE)
|
|---|
| 859 | {
|
|---|
| 860 | DWORD result;
|
|---|
| 861 | LeaveCriticalSection (&lock->lock);
|
|---|
| 862 | /* Wait until another thread signals this event. */
|
|---|
| 863 | result = WaitForSingleObject (event, INFINITE);
|
|---|
| 864 | if (result == WAIT_FAILED || result == WAIT_TIMEOUT)
|
|---|
| 865 | abort ();
|
|---|
| 866 | CloseHandle (event);
|
|---|
| 867 | /* The thread which signalled the event already did the bookkeeping:
|
|---|
| 868 | removed us from the waiting_writers, set lock->runcount = -1. */
|
|---|
| 869 | if (!(lock->runcount == -1))
|
|---|
| 870 | abort ();
|
|---|
| 871 | return 0;
|
|---|
| 872 | }
|
|---|
| 873 | else
|
|---|
| 874 | {
|
|---|
| 875 | /* Allocation failure. Weird. */
|
|---|
| 876 | do
|
|---|
| 877 | {
|
|---|
| 878 | LeaveCriticalSection (&lock->lock);
|
|---|
| 879 | Sleep (1);
|
|---|
| 880 | EnterCriticalSection (&lock->lock);
|
|---|
| 881 | }
|
|---|
| 882 | while (!(lock->runcount == 0));
|
|---|
| 883 | }
|
|---|
| 884 | }
|
|---|
| 885 | lock->runcount--; /* runcount becomes -1 */
|
|---|
| 886 | LeaveCriticalSection (&lock->lock);
|
|---|
| 887 | return 0;
|
|---|
| 888 | }
|
|---|
| 889 |
|
|---|
| 890 | int
|
|---|
| 891 | glthread_rwlock_unlock_func (gl_rwlock_t *lock)
|
|---|
| 892 | {
|
|---|
| 893 | if (!lock->guard.done)
|
|---|
| 894 | return EINVAL;
|
|---|
| 895 | EnterCriticalSection (&lock->lock);
|
|---|
| 896 | if (lock->runcount < 0)
|
|---|
| 897 | {
|
|---|
| 898 | /* Drop a writer lock. */
|
|---|
| 899 | if (!(lock->runcount == -1))
|
|---|
| 900 | abort ();
|
|---|
| 901 | lock->runcount = 0;
|
|---|
| 902 | }
|
|---|
| 903 | else
|
|---|
| 904 | {
|
|---|
| 905 | /* Drop a reader lock. */
|
|---|
| 906 | if (!(lock->runcount > 0))
|
|---|
| 907 | {
|
|---|
| 908 | LeaveCriticalSection (&lock->lock);
|
|---|
| 909 | return EPERM;
|
|---|
| 910 | }
|
|---|
| 911 | lock->runcount--;
|
|---|
| 912 | }
|
|---|
| 913 | if (lock->runcount == 0)
|
|---|
| 914 | {
|
|---|
| 915 | /* POSIX recommends that "write locks shall take precedence over read
|
|---|
| 916 | locks", to avoid "writer starvation". */
|
|---|
| 917 | if (lock->waiting_writers.count > 0)
|
|---|
| 918 | {
|
|---|
| 919 | /* Wake up one of the waiting writers. */
|
|---|
| 920 | lock->runcount--;
|
|---|
| 921 | gl_waitqueue_notify_first (&lock->waiting_writers);
|
|---|
| 922 | }
|
|---|
| 923 | else
|
|---|
| 924 | {
|
|---|
| 925 | /* Wake up all waiting readers. */
|
|---|
| 926 | lock->runcount += lock->waiting_readers.count;
|
|---|
| 927 | gl_waitqueue_notify_all (&lock->waiting_readers);
|
|---|
| 928 | }
|
|---|
| 929 | }
|
|---|
| 930 | LeaveCriticalSection (&lock->lock);
|
|---|
| 931 | return 0;
|
|---|
| 932 | }
|
|---|
| 933 |
|
|---|
| 934 | int
|
|---|
| 935 | glthread_rwlock_destroy_func (gl_rwlock_t *lock)
|
|---|
| 936 | {
|
|---|
| 937 | if (!lock->guard.done)
|
|---|
| 938 | return EINVAL;
|
|---|
| 939 | if (lock->runcount != 0)
|
|---|
| 940 | return EBUSY;
|
|---|
| 941 | DeleteCriticalSection (&lock->lock);
|
|---|
| 942 | if (lock->waiting_readers.array != NULL)
|
|---|
| 943 | free (lock->waiting_readers.array);
|
|---|
| 944 | if (lock->waiting_writers.array != NULL)
|
|---|
| 945 | free (lock->waiting_writers.array);
|
|---|
| 946 | lock->guard.done = 0;
|
|---|
| 947 | return 0;
|
|---|
| 948 | }
|
|---|
| 949 |
|
|---|
| 950 | /* --------------------- gl_recursive_lock_t datatype --------------------- */
|
|---|
| 951 |
|
|---|
| 952 | void
|
|---|
| 953 | glthread_recursive_lock_init_func (gl_recursive_lock_t *lock)
|
|---|
| 954 | {
|
|---|
| 955 | lock->owner = 0;
|
|---|
| 956 | lock->depth = 0;
|
|---|
| 957 | InitializeCriticalSection (&lock->lock);
|
|---|
| 958 | lock->guard.done = 1;
|
|---|
| 959 | }
|
|---|
| 960 |
|
|---|
| 961 | int
|
|---|
| 962 | glthread_recursive_lock_lock_func (gl_recursive_lock_t *lock)
|
|---|
| 963 | {
|
|---|
| 964 | if (!lock->guard.done)
|
|---|
| 965 | {
|
|---|
| 966 | if (InterlockedIncrement (&lock->guard.started) == 0)
|
|---|
| 967 | /* This thread is the first one to need this lock. Initialize it. */
|
|---|
| 968 | glthread_recursive_lock_init (lock);
|
|---|
| 969 | else
|
|---|
| 970 | /* Yield the CPU while waiting for another thread to finish
|
|---|
| 971 | initializing this lock. */
|
|---|
| 972 | while (!lock->guard.done)
|
|---|
| 973 | Sleep (0);
|
|---|
| 974 | }
|
|---|
| 975 | {
|
|---|
| 976 | DWORD self = GetCurrentThreadId ();
|
|---|
| 977 | if (lock->owner != self)
|
|---|
| 978 | {
|
|---|
| 979 | EnterCriticalSection (&lock->lock);
|
|---|
| 980 | lock->owner = self;
|
|---|
| 981 | }
|
|---|
| 982 | if (++(lock->depth) == 0) /* wraparound? */
|
|---|
| 983 | {
|
|---|
| 984 | lock->depth--;
|
|---|
| 985 | return EAGAIN;
|
|---|
| 986 | }
|
|---|
| 987 | }
|
|---|
| 988 | return 0;
|
|---|
| 989 | }
|
|---|
| 990 |
|
|---|
| 991 | int
|
|---|
| 992 | glthread_recursive_lock_unlock_func (gl_recursive_lock_t *lock)
|
|---|
| 993 | {
|
|---|
| 994 | if (lock->owner != GetCurrentThreadId ())
|
|---|
| 995 | return EPERM;
|
|---|
| 996 | if (lock->depth == 0)
|
|---|
| 997 | return EINVAL;
|
|---|
| 998 | if (--(lock->depth) == 0)
|
|---|
| 999 | {
|
|---|
| 1000 | lock->owner = 0;
|
|---|
| 1001 | LeaveCriticalSection (&lock->lock);
|
|---|
| 1002 | }
|
|---|
| 1003 | return 0;
|
|---|
| 1004 | }
|
|---|
| 1005 |
|
|---|
| 1006 | int
|
|---|
| 1007 | glthread_recursive_lock_destroy_func (gl_recursive_lock_t *lock)
|
|---|
| 1008 | {
|
|---|
| 1009 | if (lock->owner != 0)
|
|---|
| 1010 | return EBUSY;
|
|---|
| 1011 | DeleteCriticalSection (&lock->lock);
|
|---|
| 1012 | lock->guard.done = 0;
|
|---|
| 1013 | return 0;
|
|---|
| 1014 | }
|
|---|
| 1015 |
|
|---|
| 1016 | /* -------------------------- gl_once_t datatype -------------------------- */
|
|---|
| 1017 |
|
|---|
| 1018 | void
|
|---|
| 1019 | glthread_once_func (gl_once_t *once_control, void (*initfunction) (void))
|
|---|
| 1020 | {
|
|---|
| 1021 | if (once_control->inited <= 0)
|
|---|
| 1022 | {
|
|---|
| 1023 | if (InterlockedIncrement (&once_control->started) == 0)
|
|---|
| 1024 | {
|
|---|
| 1025 | /* This thread is the first one to come to this once_control. */
|
|---|
| 1026 | InitializeCriticalSection (&once_control->lock);
|
|---|
| 1027 | EnterCriticalSection (&once_control->lock);
|
|---|
| 1028 | once_control->inited = 0;
|
|---|
| 1029 | initfunction ();
|
|---|
| 1030 | once_control->inited = 1;
|
|---|
| 1031 | LeaveCriticalSection (&once_control->lock);
|
|---|
| 1032 | }
|
|---|
| 1033 | else
|
|---|
| 1034 | {
|
|---|
| 1035 | /* Undo last operation. */
|
|---|
| 1036 | InterlockedDecrement (&once_control->started);
|
|---|
| 1037 | /* Some other thread has already started the initialization.
|
|---|
| 1038 | Yield the CPU while waiting for the other thread to finish
|
|---|
| 1039 | initializing and taking the lock. */
|
|---|
| 1040 | while (once_control->inited < 0)
|
|---|
| 1041 | Sleep (0);
|
|---|
| 1042 | if (once_control->inited <= 0)
|
|---|
| 1043 | {
|
|---|
| 1044 | /* Take the lock. This blocks until the other thread has
|
|---|
| 1045 | finished calling the initfunction. */
|
|---|
| 1046 | EnterCriticalSection (&once_control->lock);
|
|---|
| 1047 | LeaveCriticalSection (&once_control->lock);
|
|---|
| 1048 | if (!(once_control->inited > 0))
|
|---|
| 1049 | abort ();
|
|---|
| 1050 | }
|
|---|
| 1051 | }
|
|---|
| 1052 | }
|
|---|
| 1053 | }
|
|---|
| 1054 |
|
|---|
| 1055 | #endif
|
|---|
| 1056 |
|
|---|
| 1057 | /* ========================================================================= */
|
|---|