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/* $NetBSD: counter.c,v 1.1.1.2 2014/12/10 03:34:43 christos Exp $ */
/*
* Copyright (C) 2014 Internet Systems Consortium, Inc. ("ISC")
*
* Permission to use, copy, modify, and/or 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 ISC DISCLAIMS ALL WARRANTIES WITH
* REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS. IN NO EVENT SHALL ISC 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.
*/
/*! \file */
#include <config.h>
#include <stddef.h>
#include <isc/counter.h>
#include <isc/magic.h>
#include <isc/mem.h>
#include <isc/util.h>
#define COUNTER_MAGIC ISC_MAGIC('C', 'n', 't', 'r')
#define VALID_COUNTER(r) ISC_MAGIC_VALID(r, COUNTER_MAGIC)
struct isc_counter {
unsigned int magic;
isc_mem_t *mctx;
isc_mutex_t lock;
unsigned int references;
unsigned int limit;
unsigned int used;
};
isc_result_t
isc_counter_create(isc_mem_t *mctx, int limit, isc_counter_t **counterp) {
isc_result_t result;
isc_counter_t *counter;
REQUIRE(counterp != NULL && *counterp == NULL);
counter = isc_mem_get(mctx, sizeof(*counter));
if (counter == NULL)
return (ISC_R_NOMEMORY);
result = isc_mutex_init(&counter->lock);
if (result != ISC_R_SUCCESS) {
isc_mem_put(mctx, counter, sizeof(*counter));
return (result);
}
counter->mctx = NULL;
isc_mem_attach(mctx, &counter->mctx);
counter->references = 1;
counter->limit = limit;
counter->used = 0;
counter->magic = COUNTER_MAGIC;
*counterp = counter;
return (ISC_R_SUCCESS);
}
isc_result_t
isc_counter_increment(isc_counter_t *counter) {
isc_result_t result = ISC_R_SUCCESS;
LOCK(&counter->lock);
counter->used++;
if (counter->limit != 0 && counter->used >= counter->limit)
result = ISC_R_QUOTA;
UNLOCK(&counter->lock);
return (result);
}
unsigned int
isc_counter_used(isc_counter_t *counter) {
REQUIRE(VALID_COUNTER(counter));
return (counter->used);
}
void
isc_counter_setlimit(isc_counter_t *counter, int limit) {
REQUIRE(VALID_COUNTER(counter));
LOCK(&counter->lock);
counter->limit = limit;
UNLOCK(&counter->lock);
}
void
isc_counter_attach(isc_counter_t *source, isc_counter_t **targetp) {
REQUIRE(VALID_COUNTER(source));
REQUIRE(targetp != NULL && *targetp == NULL);
LOCK(&source->lock);
source->references++;
INSIST(source->references > 0);
UNLOCK(&source->lock);
*targetp = source;
}
static void
destroy(isc_counter_t *counter) {
counter->magic = 0;
isc_mutex_destroy(&counter->lock);
isc_mem_putanddetach(&counter->mctx, counter, sizeof(*counter));
}
void
isc_counter_detach(isc_counter_t **counterp) {
isc_counter_t *counter;
isc_boolean_t want_destroy = ISC_FALSE;
REQUIRE(counterp != NULL && *counterp != NULL);
counter = *counterp;
REQUIRE(VALID_COUNTER(counter));
*counterp = NULL;
LOCK(&counter->lock);
INSIST(counter->references > 0);
counter->references--;
if (counter->references == 0)
want_destroy = ISC_TRUE;
UNLOCK(&counter->lock);
if (want_destroy)
destroy(counter);
}
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