diff options
Diffstat (limited to 'externals/mysql/mysys/thr_rwlock.c')
| -rw-r--r-- | externals/mysql/mysys/thr_rwlock.c | 171 |
1 files changed, 0 insertions, 171 deletions
diff --git a/externals/mysql/mysys/thr_rwlock.c b/externals/mysql/mysys/thr_rwlock.c deleted file mode 100644 index 280a0ec19e7..00000000000 --- a/externals/mysql/mysys/thr_rwlock.c +++ /dev/null @@ -1,171 +0,0 @@ -/* Copyright (C) 2000 MySQL AB - - This program is free software; you can redistribute it and/or modify - it under the terms of the GNU General Public License as published by - the Free Software Foundation; version 2 of the License. - - This program is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - GNU General Public License for more details. - - You should have received a copy of the GNU General Public License - along with this program; if not, write to the Free Software - Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ - -/* Synchronization - readers / writer thread locks */ - -#include "mysys_priv.h" -#if defined(THREAD) && !defined(HAVE_PTHREAD_RWLOCK_RDLOCK) && !defined(HAVE_RWLOCK_INIT) -#include <errno.h> - -/* - Source base from Sun Microsystems SPILT, simplified for MySQL use - -- Joshua Chamas - Some cleanup and additional code by Monty -*/ - -/* -* Multithreaded Demo Source -* -* Copyright (C) 1995 by Sun Microsystems, Inc. -* All rights reserved. -* -* This file is a product of SunSoft, Inc. and is provided for -* unrestricted use provided that this legend is included on all -* media and as a part of the software program in whole or part. -* Users may copy, modify or distribute this file at will. -* -* THIS FILE IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING -* THE WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR -* PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE. -* -* This file is provided with no support and without any obligation on the -* part of SunSoft, Inc. to assist in its use, correction, modification or -* enhancement. -* -* SUNSOFT AND SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT -* TO THE INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY THIS -* FILE OR ANY PART THEREOF. -* -* IN NO EVENT WILL SUNSOFT OR SUN MICROSYSTEMS, INC. BE LIABLE FOR ANY -* LOST REVENUE OR PROFITS OR OTHER SPECIAL, INDIRECT AND CONSEQUENTIAL -* DAMAGES, EVEN IF THEY HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH -* DAMAGES. -* -* SunSoft, Inc. -* 2550 Garcia Avenue -* Mountain View, California 94043 -*/ - -int my_rwlock_init(rw_lock_t *rwp, void *arg __attribute__((unused))) -{ - pthread_condattr_t cond_attr; - - pthread_mutex_init( &rwp->lock, MY_MUTEX_INIT_FAST); - pthread_condattr_init( &cond_attr ); - pthread_cond_init( &rwp->readers, &cond_attr ); - pthread_cond_init( &rwp->writers, &cond_attr ); - pthread_condattr_destroy(&cond_attr); - - rwp->state = 0; - rwp->waiters = 0; - - return(0); -} - - -int my_rwlock_destroy(rw_lock_t *rwp) -{ - pthread_mutex_destroy( &rwp->lock ); - pthread_cond_destroy( &rwp->readers ); - pthread_cond_destroy( &rwp->writers ); - return(0); -} - - -int my_rw_rdlock(rw_lock_t *rwp) -{ - pthread_mutex_lock(&rwp->lock); - - /* active or queued writers */ - while ((rwp->state < 0 ) || rwp->waiters) - pthread_cond_wait( &rwp->readers, &rwp->lock); - - rwp->state++; - pthread_mutex_unlock(&rwp->lock); - return(0); -} - -int my_rw_tryrdlock(rw_lock_t *rwp) -{ - int res; - pthread_mutex_lock(&rwp->lock); - if ((rwp->state < 0 ) || rwp->waiters) - res= EBUSY; /* Can't get lock */ - else - { - res=0; - rwp->state++; - } - pthread_mutex_unlock(&rwp->lock); - return(res); -} - - -int my_rw_wrlock(rw_lock_t *rwp) -{ - pthread_mutex_lock(&rwp->lock); - rwp->waiters++; /* another writer queued */ - - while (rwp->state) - pthread_cond_wait(&rwp->writers, &rwp->lock); - rwp->state = -1; - rwp->waiters--; - pthread_mutex_unlock(&rwp->lock); - return(0); -} - - -int my_rw_trywrlock(rw_lock_t *rwp) -{ - int res; - pthread_mutex_lock(&rwp->lock); - if (rwp->state) - res= EBUSY; /* Can't get lock */ - else - { - res=0; - rwp->state = -1; - } - pthread_mutex_unlock(&rwp->lock); - return(res); -} - - -int my_rw_unlock(rw_lock_t *rwp) -{ - DBUG_PRINT("rw_unlock", - ("state: %d waiters: %d", rwp->state, rwp->waiters)); - pthread_mutex_lock(&rwp->lock); - - if (rwp->state == -1) /* writer releasing */ - { - rwp->state= 0; /* mark as available */ - - if ( rwp->waiters ) /* writers queued */ - pthread_cond_signal( &rwp->writers ); - else - pthread_cond_broadcast( &rwp->readers ); - } - else - { - if ( --rwp->state == 0 ) /* no more readers */ - pthread_cond_signal( &rwp->writers ); - } - - pthread_mutex_unlock( &rwp->lock ); - return(0); -} - -#endif |