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btlocks.c
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00001 /* -*- Mode: C++; c-basic-offset: 4 -*- */
00002 /* ***** BEGIN LICENSE BLOCK *****
00003  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
00004  *
00005  * The contents of this file are subject to the Mozilla Public License Version
00006  * 1.1 (the "License"); you may not use this file except in compliance with
00007  * the License. You may obtain a copy of the License at
00008  * http://www.mozilla.org/MPL/
00009  *
00010  * Software distributed under the License is distributed on an "AS IS" basis,
00011  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
00012  * for the specific language governing rights and limitations under the
00013  * License.
00014  *
00015  * The Original Code is the Netscape Portable Runtime (NSPR).
00016  *
00017  * The Initial Developer of the Original Code is
00018  * Netscape Communications Corporation.
00019  * Portions created by the Initial Developer are Copyright (C) 1998-2000
00020  * the Initial Developer. All Rights Reserved.
00021  *
00022  * Contributor(s):
00023  *
00024  * Alternatively, the contents of this file may be used under the terms of
00025  * either the GNU General Public License Version 2 or later (the "GPL"), or
00026  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
00027  * in which case the provisions of the GPL or the LGPL are applicable instead
00028  * of those above. If you wish to allow use of your version of this file only
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00036  * ***** END LICENSE BLOCK ***** */
00037 
00038 /*
00039 ** File:        btlocks.c
00040 ** Description: Implemenation for thread locks using bthreads
00041 ** Exports:     prlock.h
00042 */
00043 
00044 #include "primpl.h"
00045 
00046 #include <string.h>
00047 #include <sys/time.h>
00048 
00049 void
00050 _PR_InitLocks (void)
00051 {
00052 }
00053 
00054 PR_IMPLEMENT(PRLock*)
00055     PR_NewLock (void)
00056 {
00057     PRLock *lock;
00058     status_t semresult;
00059 
00060     if (!_pr_initialized) _PR_ImplicitInitialization();
00061 
00062     lock = PR_NEWZAP(PRLock);
00063     if (lock != NULL) {
00064 
00065        lock->benaphoreCount = 0;
00066        lock->semaphoreID = create_sem( 0, "nsprLockSem" );
00067        if( lock->semaphoreID < B_NO_ERROR ) {
00068 
00069            PR_DELETE( lock );
00070            lock = NULL;
00071        }
00072     }
00073 
00074     return lock;
00075 }
00076 
00077 PR_IMPLEMENT(void)
00078     PR_DestroyLock (PRLock* lock)
00079 {
00080     status_t result;
00081 
00082     PR_ASSERT(NULL != lock);
00083     result = delete_sem(lock->semaphoreID);
00084     PR_ASSERT(result == B_NO_ERROR);
00085     PR_DELETE(lock);
00086 }
00087 
00088 PR_IMPLEMENT(void)
00089     PR_Lock (PRLock* lock)
00090 {
00091     PR_ASSERT(lock != NULL);
00092 
00093     if( atomic_add( &lock->benaphoreCount, 1 ) > 0 ) {
00094 
00095        if( acquire_sem(lock->semaphoreID ) != B_NO_ERROR ) {
00096 
00097            atomic_add( &lock->benaphoreCount, -1 );
00098            return;
00099        }
00100     }
00101 
00102     lock->owner = find_thread( NULL );
00103 }
00104 
00105 PR_IMPLEMENT(PRStatus)
00106     PR_Unlock (PRLock* lock)
00107 {
00108     PR_ASSERT(lock != NULL);
00109     lock->owner = NULL;
00110     if( atomic_add( &lock->benaphoreCount, -1 ) > 1 ) {
00111 
00112        release_sem_etc( lock->semaphoreID, 1, B_DO_NOT_RESCHEDULE );
00113     }
00114 
00115     return PR_SUCCESS;
00116 }