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/*
* 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 http://mozilla.org/MPL/2.0/.
*
* See the COPYRIGHT file distributed with this work for additional
* information regarding copyright ownership.
*/
/*! \file */
#include <config.h>
#include <stdbool.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;
bool want_destroy = 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 = true;
UNLOCK(&counter->lock);
if (want_destroy)
destroy(counter);
}
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