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/* Copyright 2000-2005 The Apache Software Foundation or its licensors, as
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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* http://www.apache.org/licenses/LICENSE-2.0
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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/*Read/Write locking implementation based on the MultiLock code from
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* Stephen Beaulieu <hippo@be.com>
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#include "apr_arch_thread_mutex.h"
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#include "apr_strings.h"
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#include "apr_portable.h"
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static apr_status_t _thread_mutex_cleanup(void * data)
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apr_thread_mutex_t *lock = (apr_thread_mutex_t*)data;
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if (lock->LockCount != 0) {
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/* we're still locked... */
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while (atomic_add(&lock->LockCount , -1) > 1){
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/* OK we had more than one person waiting on the lock so
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* the sem is also locked. Release it until we have no more
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release_sem (lock->Lock);
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delete_sem(lock->Lock);
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APR_DECLARE(apr_status_t) apr_thread_mutex_create(apr_thread_mutex_t **mutex,
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apr_thread_mutex_t *new_m;
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apr_status_t stat = APR_SUCCESS;
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new_m = (apr_thread_mutex_t *)apr_pcalloc(pool, sizeof(apr_thread_mutex_t));
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if ((stat = create_sem(0, "APR_Lock")) < B_NO_ERROR) {
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_thread_mutex_cleanup(new_m);
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/* Optimal default is APR_THREAD_MUTEX_UNNESTED,
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* no additional checks required for either flag.
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new_m->nested = flags & APR_THREAD_MUTEX_NESTED;
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apr_pool_cleanup_register(new_m->pool, (void *)new_m, _thread_mutex_cleanup,
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apr_pool_cleanup_null);
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#if APR_HAS_CREATE_LOCKS_NP
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APR_DECLARE(apr_status_t) apr_thread_mutex_create_np(apr_thread_mutex_t **mutex,
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apr_lockmech_e_np mech,
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APR_DECLARE(apr_status_t) apr_thread_mutex_lock(apr_thread_mutex_t *mutex)
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thread_id me = find_thread(NULL);
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if (mutex->nested && mutex->owner == me) {
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if (atomic_add(&mutex->LockCount, 1) > 0) {
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if ((stat = acquire_sem(mutex->Lock)) < B_NO_ERROR) {
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/* Oh dear, acquire_sem failed!! */
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atomic_add(&mutex->LockCount, -1);
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mutex->owner_ref = 1;
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APR_DECLARE(apr_status_t) apr_thread_mutex_trylock(apr_thread_mutex_t *mutex)
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APR_DECLARE(apr_status_t) apr_thread_mutex_unlock(apr_thread_mutex_t *mutex)
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if (mutex->nested && mutex->owner == find_thread(NULL)) {
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if (mutex->owner_ref > 0)
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if (atomic_add(&mutex->LockCount, -1) > 1) {
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if ((stat = release_sem(mutex->Lock)) < B_NO_ERROR) {
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atomic_add(&mutex->LockCount, 1);
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mutex->owner_ref = 0;
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APR_DECLARE(apr_status_t) apr_thread_mutex_destroy(apr_thread_mutex_t *mutex)
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if ((stat = _thread_mutex_cleanup(mutex)) == APR_SUCCESS) {
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apr_pool_cleanup_kill(mutex->pool, mutex, _thread_mutex_cleanup);
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APR_POOL_IMPLEMENT_ACCESSOR(thread_mutex)