/*
* Copyright (C) Internet Systems Consortium, Inc. ("ISC")
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, you can obtain one at https://mozilla.org/MPL/2.0/.
*
* See the COPYRIGHT file distributed with this work for additional
* information regarding copyright ownership.
*/
#ifndef ISC_QUOTA_H
#define ISC_QUOTA_H 1
/*****
***** Module Info
*****/
/*! \file isc/quota.h
*
* \brief 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/lang.h>
#include <isc/mutex.h>
#include <isc/types.h>
/*****
***** Types.
*****/
ISC_LANG_BEGINDECLS
/*% isc_quota structure */
struct isc_quota {
isc_mutex_t lock; /*%< Locked by lock. */
int max;
int used;
int soft;
};
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.
*/
void
isc_quota_soft(isc_quota_t *quota, int soft);
/*%<
* Set a soft quota.
*/
void
isc_quota_max(isc_quota_t *quota, int max);
/*%<
* Re-set a maximum quota.
*/
isc_result_t
isc_quota_reserve(isc_quota_t *quota);
/*%<
* Attempt to reserve one unit of 'quota'.
*
* Returns:
* \li #ISC_R_SUCCESS Success
* \li #ISC_R_SOFTQUOTA Success soft quota reached
* \li #ISC_R_QUOTA Quota is full
*/
void
isc_quota_release(isc_quota_t *quota);
/*%<
* Release one unit of quota.
*/
isc_result_t
isc_quota_attach(isc_quota_t *quota, isc_quota_t **p);
/*%<
* Like isc_quota_reserve, and also attaches '*p' to the
* quota if successful (ISC_R_SUCCESS or ISC_R_SOFTQUOTA).
*/
isc_result_t
isc_quota_force(isc_quota_t *quota, isc_quota_t **p);
/*%<
* Like isc_quota_attach, but will attach '*p' to the quota
* even if the hard quota has been exceeded.
*/
void
isc_quota_detach(isc_quota_t **p);
/*%<
* Like isc_quota_release, and also detaches '*p' from the
* quota.
*/
unsigned int
isc_quota_getused(isc_quota_t *quota);
/*%<
* Get the current usage of quota.
*/
ISC_LANG_ENDDECLS
#endif /* ISC_QUOTA_H */
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