quota.h revision 5f2d1b96ac4bc3870423792520030a5ecabda925
/*
* Copyright (C) 2000 Internet Software Consortium.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
* ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
* CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
* SOFTWARE.
*/
#ifndef ISC_QUOTA_H
#define ISC_QUOTA_H 1
/*****
***** Module Info
*****/
/*
* Quota
*
* The isc_quota_t object is a simple helper object for implementing
* quotas on things like the number of simultaneous connections to
* a server. It keeps track of the amount of quota in use, and
* encapsulates the locking necessary to allow multiple tasks to
* share a quota.
*/
/***
*** Imports.
***/
#include <isc/mutex.h>
#include <isc/result.h>
/*****
***** Types.
*****/
ISC_LANG_BEGINDECLS
typedef struct isc_quota isc_quota_t;
struct isc_quota {
isc_mutex_t lock;
/* Locked by lock. */
int max;
int used;
};
isc_result_t
isc_quota_init(isc_quota_t *quota, int max);
/*
* Initialize a quota object.
*
* Returns:
* ISC_R_SUCCESS
* Other error Lock creation failed.
*/
void
isc_quota_destroy(isc_quota_t *quota);
/*
* Destroy a quota object.
*/
isc_result_t
isc_quota_reserve(isc_quota_t *quota);
/*
* Attempt to reserve one unit of 'quota'.
*
* Returns:
* ISC_R_SUCCESS Success
* ISC_R_QUOTA Quota is full
*/
void
isc_quota_release(isc_quota_t *quota);
/*
* Release one unit of quota.
*/
ISC_LANG_ENDDECLS
#endif /* ISC_QUOTA_H */