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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.
*/
#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 */
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