/* * Copyright (c) 2006 Apple Computer, Inc. All rights reserved. * * @APPLE_LICENSE_HEADER_START@ * * This file contains Original Code and/or Modifications of Original Code * as defined in and that are subject to the Apple Public Source License * Version 2.0 (the 'License'). You may not use this file except in * compliance with the License. Please obtain a copy of the License at * http://www.opensource.apple.com/apsl/ and read it before using this * file. * * The Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. * * @APPLE_LICENSE_HEADER_END@ */ #include "PTLock.h" #include <stdlib.h> #include <mach/message.h> /******************************************************************************* * *******************************************************************************/ typedef struct __PTLock { Boolean locked; pthread_mutex_t mutex; pthread_cond_t condition; } PTLock; /******************************************************************************* * *******************************************************************************/ PTLockRef PTLockCreate(void) { PTLock * lock; lock = (PTLock *)malloc(sizeof(PTLock)); if (!lock) { return NULL; } lock->locked = false; pthread_mutex_init(&lock->mutex, NULL); pthread_cond_init(&lock->condition, NULL); return (PTLockRef)lock; } /******************************************************************************* * *******************************************************************************/ void PTLockFree(PTLockRef lock) { if (!lock) { return; } pthread_mutex_destroy(&lock->mutex); pthread_cond_destroy(&lock->condition); free(lock); return; } /******************************************************************************* * *******************************************************************************/ void PTLockTakeLock(PTLockRef lock) { pthread_mutex_lock(&lock->mutex); while (lock->locked) { pthread_cond_wait(&lock->condition, &lock->mutex); } lock->locked = true; pthread_mutex_unlock(&lock->mutex); return; } /******************************************************************************* * *******************************************************************************/ void PTLockUnlock(PTLockRef lock) { pthread_mutex_lock(&lock->mutex); lock->locked = false; pthread_cond_signal(&lock->condition); pthread_mutex_unlock(&lock->mutex); return; } /******************************************************************************* * *******************************************************************************/ Boolean PTLockTryLock(PTLockRef lock) { Boolean available = false; Boolean got_it = false; pthread_mutex_lock(&lock->mutex); available = !lock->locked; if (available) { lock->locked = true; got_it = true; } pthread_mutex_unlock(&lock->mutex); return got_it; }