1/*
2 * root_pools.c :  Implement svn_root_pools__* API
3 *
4 * ====================================================================
5 *    Licensed to the Apache Software Foundation (ASF) under one
6 *    or more contributor license agreements.  See the NOTICE file
7 *    distributed with this work for additional information
8 *    regarding copyright ownership.  The ASF licenses this file
9 *    to you under the Apache License, Version 2.0 (the
10 *    "License"); you may not use this file except in compliance
11 *    with the License.  You may obtain a copy of the License at
12 *
13 *      http://www.apache.org/licenses/LICENSE-2.0
14 *
15 *    Unless required by applicable law or agreed to in writing,
16 *    software distributed under the License is distributed on an
17 *    "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
18 *    KIND, either express or implied.  See the License for the
19 *    specific language governing permissions and limitations
20 *    under the License.
21 * ====================================================================
22 */
23
24#include "svn_pools.h"
25
26#include "private/svn_subr_private.h"
27#include "private/svn_mutex.h"
28
29struct svn_root_pools__t
30{
31  /* unused pools.
32   * Use MUTEX to serialize access to this collection.
33   */
34  apr_array_header_t *unused_pools;
35
36  /* Mutex to serialize access to UNUSED_POOLS */
37  svn_mutex__t *mutex;
38
39};
40
41svn_error_t *
42svn_root_pools__create(svn_root_pools__t **pools)
43{
44  /* the collection of root pools must be managed independently from
45     any other pool */
46  apr_pool_t *pool
47    = apr_allocator_owner_get(svn_pool_create_allocator(FALSE));
48
49  /* construct result object */
50  svn_root_pools__t *result = apr_pcalloc(pool, sizeof(*result));
51  SVN_ERR(svn_mutex__init(&result->mutex, TRUE, pool));
52  result->unused_pools = apr_array_make(pool, 16, sizeof(apr_pool_t *));
53
54  /* done */
55  *pools = result;
56
57  return SVN_NO_ERROR;
58}
59
60/* Return a currently unused connection pool in *POOL. If no such pool
61 * exists, create a new root pool and return that in *POOL.
62 */
63static svn_error_t *
64acquire_pool_internal(apr_pool_t **pool,
65                      svn_root_pools__t *pools)
66{
67  SVN_ERR(svn_mutex__lock(pools->mutex));
68  *pool = pools->unused_pools->nelts
69        ? *(apr_pool_t **)apr_array_pop(pools->unused_pools)
70        : apr_allocator_owner_get(svn_pool_create_allocator(FALSE));
71  SVN_ERR(svn_mutex__unlock(pools->mutex, SVN_NO_ERROR));
72
73  return SVN_NO_ERROR;
74}
75
76apr_pool_t *
77svn_root_pools__acquire_pool(svn_root_pools__t *pools)
78{
79  apr_pool_t *pool;
80  svn_error_t *err = acquire_pool_internal(&pool, pools);
81  if (err)
82    {
83      /* Mutex failure?!  Well, try to continue with unrecycled data. */
84      svn_error_clear(err);
85      pool = apr_allocator_owner_get(svn_pool_create_allocator(FALSE));
86    }
87
88  return pool;
89}
90
91void
92svn_root_pools__release_pool(apr_pool_t *pool,
93                             svn_root_pools__t *pools)
94{
95  svn_error_t *err;
96
97  svn_pool_clear(pool);
98
99  err = svn_mutex__lock(pools->mutex);
100  if (err)
101    {
102      svn_error_clear(err);
103      svn_pool_destroy(pool);
104    }
105  else
106    {
107      APR_ARRAY_PUSH(pools->unused_pools, apr_pool_t *) = pool;
108      svn_error_clear(svn_mutex__unlock(pools->mutex, SVN_NO_ERROR));
109    }
110}
111