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/*
* svn_mutex.c: routines for mutual exclusion.
*
* ====================================================================
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
* ====================================================================
*/
#include <apr_portable.h>
#include "svn_private_config.h"
#include "private/svn_atomic.h"
#include "private/svn_mutex.h"
/* With CHECKED set to TRUE, LOCKED and OWNER must be set *after* acquiring
* the MUTEX and be reset *before* releasing it again. This is sufficient
* because we only want to check whether the current thread already holds
* the lock. And the current thread cannot be acquiring / releasing a lock
* *while* checking for recursion at the same time.
*/
struct svn_mutex__t
{
#if APR_HAS_THREADS
apr_thread_mutex_t *mutex;
#else
/* Truly empty structs are not allowed. */
int dummy;
#endif
};
svn_error_t *
svn_mutex__init(svn_mutex__t **mutex_p,
svn_boolean_t mutex_required,
apr_pool_t *result_pool)
{
/* always initialize the mutex pointer, even though it is not
strictly necessary if APR_HAS_THREADS has not been set */
*mutex_p = NULL;
if (mutex_required)
{
svn_mutex__t *mutex = apr_pcalloc(result_pool, sizeof(*mutex));
#if APR_HAS_THREADS
apr_status_t status =
apr_thread_mutex_create(&mutex->mutex,
APR_THREAD_MUTEX_DEFAULT,
result_pool);
if (status)
return svn_error_wrap_apr(status, _("Can't create mutex"));
#endif
*mutex_p = mutex;
}
return SVN_NO_ERROR;
}
svn_error_t *
svn_mutex__lock(svn_mutex__t *mutex)
{
if (mutex)
{
#if APR_HAS_THREADS
apr_status_t status = apr_thread_mutex_lock(mutex->mutex);
if (status)
return svn_error_wrap_apr(status, _("Can't lock mutex"));
#endif
}
return SVN_NO_ERROR;
}
svn_error_t *
svn_mutex__unlock(svn_mutex__t *mutex,
svn_error_t *err)
{
if (mutex)
{
#if APR_HAS_THREADS
apr_status_t status = apr_thread_mutex_unlock(mutex->mutex);
if (status && !err)
return svn_error_wrap_apr(status, _("Can't unlock mutex"));
#endif
}
return err;
}
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