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/*
* ====================================================================
* 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_thread_mutex.h>
#include <apr_hash.h>
#include "svn_dso.h"
#include "svn_pools.h"
#include "svn_private_config.h"
/* A mutex to protect our global pool and cache. */
#if APR_HAS_THREADS
static apr_thread_mutex_t *dso_mutex;
#endif
/* Global pool to allocate DSOs in. */
static apr_pool_t *dso_pool;
/* Global cache for storing DSO objects. */
static apr_hash_t *dso_cache;
/* Just an arbitrary location in memory... */
static int not_there_sentinel;
/* A specific value we store in the dso_cache to indicate that the
library wasn't found. This keeps us from allocating extra memory
from dso_pool when trying to find libraries we already know aren't
there. */
#define NOT_THERE ((void *) ¬_there_sentinel)
svn_error_t *
svn_dso_initialize2(void)
{
#if APR_HAS_THREADS
apr_status_t status;
#endif
if (dso_pool)
return SVN_NO_ERROR;
dso_pool = svn_pool_create(NULL);
#if APR_HAS_THREADS
status = apr_thread_mutex_create(&dso_mutex,
APR_THREAD_MUTEX_DEFAULT, dso_pool);
if (status)
return svn_error_wrap_apr(status, _("Can't create DSO mutex"));
#endif
dso_cache = apr_hash_make(dso_pool);
return SVN_NO_ERROR;
}
#if APR_HAS_DSO
svn_error_t *
svn_dso_load(apr_dso_handle_t **dso, const char *fname)
{
apr_status_t status;
if (! dso_pool)
SVN_ERR(svn_dso_initialize2());
#if APR_HAS_THREADS
status = apr_thread_mutex_lock(dso_mutex);
if (status)
return svn_error_wrap_apr(status, _("Can't grab DSO mutex"));
#endif
*dso = apr_hash_get(dso_cache, fname, APR_HASH_KEY_STRING);
/* First check to see if we've been through this before... We do this
to avoid calling apr_dso_load multiple times for a given library,
which would result in wasting small amounts of memory each time. */
if (*dso == NOT_THERE)
{
*dso = NULL;
#if APR_HAS_THREADS
status = apr_thread_mutex_unlock(dso_mutex);
if (status)
return svn_error_wrap_apr(status, _("Can't ungrab DSO mutex"));
#endif
return SVN_NO_ERROR;
}
/* If we got nothing back from the cache, try and load the library. */
if (! *dso)
{
status = apr_dso_load(dso, fname, dso_pool);
if (status)
{
#if 0
char buf[1024];
fprintf(stderr, "%s\n", apr_dso_error(*dso, buf, 1024));
#endif
*dso = NULL;
/* It wasn't found, so set the special "we didn't find it" value. */
apr_hash_set(dso_cache,
apr_pstrdup(dso_pool, fname),
APR_HASH_KEY_STRING,
NOT_THERE);
#if APR_HAS_THREADS
status = apr_thread_mutex_unlock(dso_mutex);
if (status)
return svn_error_wrap_apr(status, _("Can't ungrab DSO mutex"));
#endif
return SVN_NO_ERROR;
}
/* Stash the dso so we can use it next time. */
apr_hash_set(dso_cache,
apr_pstrdup(dso_pool, fname),
APR_HASH_KEY_STRING,
*dso);
}
#if APR_HAS_THREADS
status = apr_thread_mutex_unlock(dso_mutex);
if (status)
return svn_error_wrap_apr(status, _("Can't ungrab DSO mutex"));
#endif
return SVN_NO_ERROR;
}
#endif /* APR_HAS_DSO */
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