1 /* Licensed to the Apache Software Foundation (ASF) under one or more
2 * contributor license agreements. See the NOTICE file distributed with
3 * this work for additional information regarding copyright ownership.
4 * The ASF licenses this file to You under the Apache License, Version 2.0
5 * (the "License"); you may not use this file except in compliance with
6 * the License. You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
22 * @brief APR-UTIL Resource List Routines
27 #include "apr_pools.h"
28 #include "apr_errno.h"
32 * @defgroup APR_Util_RL Resource List Routines
39 #endif /* __cplusplus */
41 /** Opaque resource list object */
42 typedef struct apr_reslist_t apr_reslist_t;
44 /* Generic constructor called by resource list when it needs to create a
46 * @param resource opaque resource
50 typedef apr_status_t (*apr_reslist_constructor)(void **resource, void *params,
53 /* Generic destructor called by resource list when it needs to destroy a
55 * @param resource opaque resource
59 typedef apr_status_t (*apr_reslist_destructor)(void *resource, void *params,
62 /* Cleanup order modes */
63 #define APR_RESLIST_CLEANUP_DEFAULT 0 /**< default pool cleanup */
64 #define APR_RESLIST_CLEANUP_FIRST 1 /**< use pool pre cleanup */
67 * Create a new resource list with the following parameters:
68 * @param reslist An address where the pointer to the new resource
69 * list will be stored.
70 * @param min Allowed minimum number of available resources. Zero
71 * creates new resources only when needed.
72 * @param smax Resources will be destroyed during reslist maintenance to
73 * meet this maximum restriction as they expire (reach their ttl).
74 * @param hmax Absolute maximum limit on the number of total resources.
75 * @param ttl If non-zero, sets the maximum amount of time in microseconds an
76 * unused resource is valid. Any resource which has exceeded this
77 * time will be destroyed, either when encountered by
78 * apr_reslist_acquire() or during reslist maintenance.
79 * @param con Constructor routine that is called to create a new resource.
80 * @param de Destructor routine that is called to destroy an expired resource.
81 * @param params Passed to constructor and deconstructor
82 * @param pool The pool from which to create this resource list. Also the
83 * same pool that is passed to the constructor and destructor
85 * @remark If APR has been compiled without thread support, hmax will be
86 * automatically set to 1 and values of min and smax will be forced to
87 * 1 for any non-zero value.
89 APU_DECLARE(apr_status_t) apr_reslist_create(apr_reslist_t **reslist,
90 int min, int smax, int hmax,
91 apr_interval_time_t ttl,
92 apr_reslist_constructor con,
93 apr_reslist_destructor de,
98 * Destroy the given resource list and all resources controlled by
100 * FIXME: Should this block until all resources become available,
101 * or maybe just destroy all the free ones, or maybe destroy
102 * them even though they might be in use by something else?
103 * Currently it will abort if there are resources that haven't
104 * been released, so there is an assumption that all resources
105 * have been released to the list before calling this function.
106 * @param reslist The reslist to destroy
108 APU_DECLARE(apr_status_t) apr_reslist_destroy(apr_reslist_t *reslist);
111 * Retrieve a resource from the list, creating a new one if necessary.
112 * If we have met our maximum number of resources, we will block
113 * until one becomes available.
115 APU_DECLARE(apr_status_t) apr_reslist_acquire(apr_reslist_t *reslist,
119 * Return a resource back to the list of available resources.
121 APU_DECLARE(apr_status_t) apr_reslist_release(apr_reslist_t *reslist,
125 * Set the timeout the acquire will wait for a free resource
126 * when the maximum number of resources is exceeded.
127 * @param reslist The resource list.
128 * @param timeout Timeout to wait. The zero waits forever.
130 APU_DECLARE(void) apr_reslist_timeout_set(apr_reslist_t *reslist,
131 apr_interval_time_t timeout);
134 * Return the number of outstanding resources.
135 * @param reslist The resource list.
137 APU_DECLARE(apr_uint32_t) apr_reslist_acquired_count(apr_reslist_t *reslist);
140 * Invalidate a resource in the pool - e.g. a database connection
141 * that returns a "lost connection" error and can't be restored.
142 * Use this instead of apr_reslist_release if the resource is bad.
144 APU_DECLARE(apr_status_t) apr_reslist_invalidate(apr_reslist_t *reslist,
148 * Perform routine maintenance on the resource list. This call
149 * may instantiate new resources or expire old resources.
150 * @param reslist The resource list.
152 APU_DECLARE(apr_status_t) apr_reslist_maintain(apr_reslist_t *reslist);
155 * Set reslist cleanup order.
156 * @param reslist The resource list.
157 * @param mode Cleanup order mode
159 * APR_RESLIST_CLEANUP_DEFAULT default pool cleanup order
160 * APR_RESLIST_CLEANUP_FIRST use pool pre cleanup
162 * @remark If APR_RESLIST_CLEANUP_FIRST is used the destructors will
163 * be called before child pools of the pool used to create the reslist
164 * are destroyed. This allows to explicitly destroy the child pools
165 * inside reslist destructors.
167 APU_DECLARE(void) apr_reslist_cleanup_order_set(apr_reslist_t *reslist,
176 #endif /* ! APR_RESLIST_H */