dist/include/apr_reslist.h

/* 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.
 */

#ifndef APR_RESLIST_H
#define APR_RESLIST_H

/** 
 * @file apr_reslist.h
 * @brief APR-UTIL Resource List Routines
 */

#include "apr.h"
#include "apu.h"
#include "apr_pools.h"
#include "apr_errno.h"
#include "apr_time.h"

/**
 * @defgroup APR_Util_RL Resource List Routines
 * @ingroup APR_Util
 * @{
 */

#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */

/** Opaque resource list object */
typedef struct apr_reslist_t apr_reslist_t;

/* Generic constructor called by resource list when it needs to create a
 * resource.
 * @param resource opaque resource
 * @param params flags
 * @param pool  Pool
 */
typedef apr_status_t (*apr_reslist_constructor)(void **resource, void *params,
                                                apr_pool_t *pool);

/* Generic destructor called by resource list when it needs to destroy a
 * resource.
 * @param resource opaque resource
 * @param params flags
 * @param pool  Pool
 */
typedef apr_status_t (*apr_reslist_destructor)(void *resource, void *params,
                                               apr_pool_t *pool);

/* Cleanup order modes */
#define APR_RESLIST_CLEANUP_DEFAULT  0       /**< default pool cleanup */
#define APR_RESLIST_CLEANUP_FIRST    1       /**< use pool pre cleanup */

/**
 * Create a new resource list with the following parameters:
 * @param reslist An address where the pointer to the new resource
 *                list will be stored.
 * @param min Allowed minimum number of available resources. Zero
 *            creates new resources only when needed.
 * @param smax Resources will be destroyed during reslist maintenance to
 *             meet this maximum restriction as they expire (reach their ttl).
 * @param hmax Absolute maximum limit on the number of total resources.
 * @param ttl If non-zero, sets the maximum amount of time in microseconds an
 *            unused resource is valid.  Any resource which has exceeded this
 *            time will be destroyed, either when encountered by
 *            apr_reslist_acquire() or during reslist maintenance.
 * @param con Constructor routine that is called to create a new resource.
 * @param de Destructor routine that is called to destroy an expired resource.
 * @param params Passed to constructor and deconstructor
 * @param pool The pool from which to create this resource list. Also the
 *             same pool that is passed to the constructor and destructor
 *             routines.
 * @remark If APR has been compiled without thread support, hmax will be
 *         automatically set to 1 and values of min and smax will be forced to
 *         1 for any non-zero value.
 */
APU_DECLARE(apr_status_t) apr_reslist_create(apr_reslist_t **reslist,
                                             int min, int smax, int hmax,
                                             apr_interval_time_t ttl,
                                             apr_reslist_constructor con,
                                             apr_reslist_destructor de,
                                             void *params,
                                             apr_pool_t *pool);

/**
 * Destroy the given resource list and all resources controlled by
 * this list.
 * FIXME: Should this block until all resources become available,
 *        or maybe just destroy all the free ones, or maybe destroy
 *        them even though they might be in use by something else?
 *        Currently it will abort if there are resources that haven't
 *        been released, so there is an assumption that all resources
 *        have been released to the list before calling this function.
 * @param reslist The reslist to destroy
 */
APU_DECLARE(apr_status_t) apr_reslist_destroy(apr_reslist_t *reslist);

/**
 * Retrieve a resource from the list, creating a new one if necessary.
 * If we have met our maximum number of resources, we will block
 * until one becomes available.
 * @param reslist The resource list.
 * @param resource An address where the pointer to the resource
 *                will be stored.
 */
APU_DECLARE(apr_status_t) apr_reslist_acquire(apr_reslist_t *reslist,
                                              void **resource);

/**
 * Return a resource back to the list of available resources.
 * @param reslist The resource list.
 * @param resource The resource to return to the list.
 */
APU_DECLARE(apr_status_t) apr_reslist_release(apr_reslist_t *reslist,
                                              void *resource);

/**
 * Set the timeout the acquire will wait for a free resource
 * when the maximum number of resources is exceeded.
 * @param reslist The resource list.
 * @param timeout Timeout to wait. The zero waits forever.
 */
APU_DECLARE(void) apr_reslist_timeout_set(apr_reslist_t *reslist,
                                          apr_interval_time_t timeout);

/**
 * Return the number of outstanding resources.
 * @param reslist The resource list.
 */
APU_DECLARE(apr_uint32_t) apr_reslist_acquired_count(apr_reslist_t *reslist);

/**
 * Invalidate a resource in the pool - e.g. a database connection
 * that returns a "lost connection" error and can't be restored.
 * Use this instead of apr_reslist_release if the resource is bad.
 * @param reslist The resource list.
 * @param resource The resource to invalidate.
 */
APU_DECLARE(apr_status_t) apr_reslist_invalidate(apr_reslist_t *reslist,
                                                 void *resource);

/**
 * Perform routine maintenance on the resource list. This call
 * may instantiate new resources or expire old resources.
 * @param reslist The resource list.
 */
APU_DECLARE(apr_status_t) apr_reslist_maintain(apr_reslist_t *reslist);

/**
 * Set reslist cleanup order.
 * @param reslist The resource list.
 * @param mode Cleanup order mode
 * <PRE>
 *           APR_RESLIST_CLEANUP_DEFAULT  default pool cleanup order
 *           APR_RESLIST_CLEANUP_FIRST    use pool pre cleanup
 * </PRE>
 * @remark If APR_RESLIST_CLEANUP_FIRST is used the destructors will
 * be called before child pools of the pool used to create the reslist
 * are destroyed. This allows to explicitly destroy the child pools
 * inside reslist destructors.
 */
APU_DECLARE(void) apr_reslist_cleanup_order_set(apr_reslist_t *reslist,
                                                apr_uint32_t mode);

#ifdef __cplusplus
}
#endif

/** @} */

#endif  /* ! APR_RESLIST_H */
Revision:	9276
Committed:	Mon Feb 20 03:10:27 2017 UTC (7 years, 2 months ago) by laffer1
Content type:	text/plain
File size:	7176 byte(s)
Log Message:	apr-util 1.5.4
#	Content
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
7	*
8	* http://www.apache.org/licenses/LICENSE-2.0
9	*
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.
15	*/
16
17	#ifndef APR_RESLIST_H
18	#define APR_RESLIST_H
19
20	/**
21	* @file apr_reslist.h
22	* @brief APR-UTIL Resource List Routines
23	*/
24
25	#include "apr.h"
26	#include "apu.h"
27	#include "apr_pools.h"
28	#include "apr_errno.h"
29	#include "apr_time.h"
30
31	/**
32	* @defgroup APR_Util_RL Resource List Routines
33	* @ingroup APR_Util
34	* @{
35	*/
36
37	#ifdef __cplusplus
38	extern "C" {
39	#endif /* __cplusplus */
40
41	/** Opaque resource list object */
42	typedef struct apr_reslist_t apr_reslist_t;
43
44	/* Generic constructor called by resource list when it needs to create a
45	* resource.
46	* @param resource opaque resource
47	* @param params flags
48	* @param pool Pool
49	*/
50	typedef apr_status_t (apr_reslist_constructor)(void resource, void params,
51	apr_pool_t *pool);
52
53	/* Generic destructor called by resource list when it needs to destroy a
54	* resource.
55	* @param resource opaque resource
56	* @param params flags
57	* @param pool Pool
58	*/
59	typedef apr_status_t (apr_reslist_destructor)(void resource, void *params,
60	apr_pool_t *pool);
61
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 /
65
66	/**
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
84	* routines.
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.
88	*/
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,
94	void *params,
95	apr_pool_t *pool);
96
97	/**
98	* Destroy the given resource list and all resources controlled by
99	* this list.
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
107	*/
108	APU_DECLARE(apr_status_t) apr_reslist_destroy(apr_reslist_t *reslist);
109
110	/**
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.
114	* @param reslist The resource list.
115	* @param resource An address where the pointer to the resource
116	* will be stored.
117	*/
118	APU_DECLARE(apr_status_t) apr_reslist_acquire(apr_reslist_t *reslist,
119	void **resource);
120
121	/**
122	* Return a resource back to the list of available resources.
123	* @param reslist The resource list.
124	* @param resource The resource to return to the list.
125	*/
126	APU_DECLARE(apr_status_t) apr_reslist_release(apr_reslist_t *reslist,
127	void *resource);
128
129	/**
130	* Set the timeout the acquire will wait for a free resource
131	* when the maximum number of resources is exceeded.
132	* @param reslist The resource list.
133	* @param timeout Timeout to wait. The zero waits forever.
134	*/
135	APU_DECLARE(void) apr_reslist_timeout_set(apr_reslist_t *reslist,
136	apr_interval_time_t timeout);
137
138	/**
139	* Return the number of outstanding resources.
140	* @param reslist The resource list.
141	*/
142	APU_DECLARE(apr_uint32_t) apr_reslist_acquired_count(apr_reslist_t *reslist);
143
144	/**
145	* Invalidate a resource in the pool - e.g. a database connection
146	* that returns a "lost connection" error and can't be restored.
147	* Use this instead of apr_reslist_release if the resource is bad.
148	* @param reslist The resource list.
149	* @param resource The resource to invalidate.
150	*/
151	APU_DECLARE(apr_status_t) apr_reslist_invalidate(apr_reslist_t *reslist,
152	void *resource);
153
154	/**
155	* Perform routine maintenance on the resource list. This call
156	* may instantiate new resources or expire old resources.
157	* @param reslist The resource list.
158	*/
159	APU_DECLARE(apr_status_t) apr_reslist_maintain(apr_reslist_t *reslist);
160
161	/**
162	* Set reslist cleanup order.
163	* @param reslist The resource list.
164	* @param mode Cleanup order mode
165	* <PRE>
166	* APR_RESLIST_CLEANUP_DEFAULT default pool cleanup order
167	* APR_RESLIST_CLEANUP_FIRST use pool pre cleanup
168	* </PRE>
169	* @remark If APR_RESLIST_CLEANUP_FIRST is used the destructors will
170	* be called before child pools of the pool used to create the reslist
171	* are destroyed. This allows to explicitly destroy the child pools
172	* inside reslist destructors.
173	*/
174	APU_DECLARE(void) apr_reslist_cleanup_order_set(apr_reslist_t *reslist,
175	apr_uint32_t mode);
176
177	#ifdef __cplusplus
178	}
179	#endif
180
181	/** @} */
182
183	#endif /* ! APR_RESLIST_H */