+/* $OpenLDAP$ */
/*
** This is an improved implementation of Reader/Writer locks does
** not protect writers from starvation. That is, if a writer is
#include "portable.h"
-#include <stdlib.h>
+#include <ac/stdlib.h>
#include <ac/errno.h>
#include <ac/string.h>
int
ldap_pvt_thread_rdwr_init( ldap_pvt_thread_rdwr_t *rw )
{
+ assert( rw != NULL );
+
memset( rw, 0, sizeof(ldap_pvt_thread_rdwr_t) );
/* we should check return results */
int
ldap_pvt_thread_rdwr_destroy( ldap_pvt_thread_rdwr_t *rw )
{
+ assert( rw != NULL );
+ assert( rw->ltrw_valid == LDAP_PVT_THREAD_RDWR_VALID );
+
if( rw->ltrw_valid != LDAP_PVT_THREAD_RDWR_VALID )
return LDAP_PVT_THREAD_EINVAL;
ldap_pvt_thread_mutex_lock( &rw->ltrw_mutex );
/* active threads? */
- if( rw->ltrw_r_active > 0 || rw->ltrw_w_active > 1) {
+ if( rw->ltrw_r_active > 0 || rw->ltrw_w_active > 0) {
ldap_pvt_thread_mutex_unlock( &rw->ltrw_mutex );
return LDAP_PVT_THREAD_EBUSY;
}
int ldap_pvt_thread_rdwr_rlock( ldap_pvt_thread_rdwr_t *rw )
{
+ assert( rw != NULL );
+ assert( rw->ltrw_valid == LDAP_PVT_THREAD_RDWR_VALID );
+
if( rw->ltrw_valid != LDAP_PVT_THREAD_RDWR_VALID )
return LDAP_PVT_THREAD_EINVAL;
ldap_pvt_thread_mutex_lock( &rw->ltrw_mutex );
- if( rw->ltrw_w_active > 1 ) {
+ if( rw->ltrw_w_active > 0 ) {
/* writer is active */
rw->ltrw_r_wait++;
do {
ldap_pvt_thread_cond_wait(
&rw->ltrw_read, &rw->ltrw_mutex );
- } while( rw->ltrw_w_active > 1 );
+ } while( rw->ltrw_w_active > 0 );
rw->ltrw_r_wait--;
}
int ldap_pvt_thread_rdwr_rtrylock( ldap_pvt_thread_rdwr_t *rw )
{
+ assert( rw != NULL );
+ assert( rw->ltrw_valid == LDAP_PVT_THREAD_RDWR_VALID );
+
if( rw->ltrw_valid != LDAP_PVT_THREAD_RDWR_VALID )
return LDAP_PVT_THREAD_EINVAL;
ldap_pvt_thread_mutex_lock( &rw->ltrw_mutex );
- if( rw->ltrw_w_active > 1) {
+ if( rw->ltrw_w_active > 0) {
ldap_pvt_thread_mutex_unlock( &rw->ltrw_mutex );
return LDAP_PVT_THREAD_EBUSY;
}
int ldap_pvt_thread_rdwr_runlock( ldap_pvt_thread_rdwr_t *rw )
{
+ assert( rw != NULL );
+ assert( rw->ltrw_valid == LDAP_PVT_THREAD_RDWR_VALID );
+
if( rw->ltrw_valid != LDAP_PVT_THREAD_RDWR_VALID )
return LDAP_PVT_THREAD_EINVAL;
int ldap_pvt_thread_rdwr_wlock( ldap_pvt_thread_rdwr_t *rw )
{
+ assert( rw != NULL );
+ assert( rw->ltrw_valid == LDAP_PVT_THREAD_RDWR_VALID );
+
if( rw->ltrw_valid != LDAP_PVT_THREAD_RDWR_VALID )
return LDAP_PVT_THREAD_EINVAL;
int ldap_pvt_thread_rdwr_wtrylock( ldap_pvt_thread_rdwr_t *rw )
{
+ assert( rw != NULL );
+ assert( rw->ltrw_valid == LDAP_PVT_THREAD_RDWR_VALID );
+
if( rw->ltrw_valid != LDAP_PVT_THREAD_RDWR_VALID )
return LDAP_PVT_THREAD_EINVAL;
int ldap_pvt_thread_rdwr_wunlock( ldap_pvt_thread_rdwr_t *rw )
{
+ assert( rw != NULL );
+ assert( rw->ltrw_valid == LDAP_PVT_THREAD_RDWR_VALID );
+
if( rw->ltrw_valid != LDAP_PVT_THREAD_RDWR_VALID )
return LDAP_PVT_THREAD_EINVAL;
int ldap_pvt_thread_rdwr_readers(ldap_pvt_thread_rdwr_t *rw)
{
+ assert( rw != NULL );
+ assert( rw->ltrw_valid == LDAP_PVT_THREAD_RDWR_VALID );
+
return( rw->ltrw_r_active );
}
int ldap_pvt_thread_rdwr_writers(ldap_pvt_thread_rdwr_t *rw)
{
+ assert( rw != NULL );
+ assert( rw->ltrw_valid == LDAP_PVT_THREAD_RDWR_VALID );
+
return( rw->ltrw_w_active );
}
int ldap_pvt_thread_rdwr_active(ldap_pvt_thread_rdwr_t *rw)
{
+ assert( rw != NULL );
+ assert( rw->ltrw_valid == LDAP_PVT_THREAD_RDWR_VALID );
+
return(ldap_pvt_thread_rdwr_readers(rw) +
ldap_pvt_thread_rdwr_writers(rw));
}