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/*
* Copyright (C) 2018 "IoT.bzh"
* Author José Bollo <jose.bollo@iot.bzh>
*
* Licensed 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.
*/
/******************************************************************************/
/******************************************************************************/
/* IMPLEMENTATION OF AGENT AT (@) */
/******************************************************************************/
/******************************************************************************/
#include <stdlib.h>
#include <stdint.h>
#include <stdbool.h>
#include <time.h>
#include <string.h>
#include "data.h"
#include "cyn.h"
/**
* Parse the spec to extract the derived key to ask.
*
* @param spec The specification of the derived key
* @param reference_key The originally requested key of reference
* @param derived_key The derived key or NULL for computing length
* @param buffer The buffer that handles texts or NULL for computing length
* @param szbuf The size of the buffer or 0 for computing length
* @return the total length of buffer used
*/
static
size_t
parse(
const char *spec,
const data_key_t *reference_key,
data_key_t *derived_key,
char *buffer,
size_t szbuf
) {
size_t iout, ikey, inf;
const char *val;
int sub;
/* iterate through the fields of the key */
iout = 0;
for (ikey = 0 ; ikey < KeyIdx_Count ; ikey++) {
/* compute value of the derived field */
inf = iout;
while(*spec) {
if (*spec == ':' && ikey < 3) {
/* : is the separator of key's items */
spec++;
break; /* next key */
}
if (!(*spec == '%' && spec[1])) {
/* not a % substitution mark */
if (iout < szbuf)
buffer[iout] = *spec;
iout++;
spec++;
} else {
/* what % substitution is it? */
switch(spec[1]) {
case 'c':
val = reference_key->client;
sub = 1;
break;
case 's':
val = reference_key->session;
sub = 1;
break;
case 'u':
val = reference_key->user;
sub = 1;
break;
case 'p':
val = reference_key->permission;
sub = 1;
break;
default:
/* none */
sub = 0;
break;
}
if (!sub) {
/* no substitution */
if (spec[1] != ':' && spec[1] != '%') {
/* only escape % and : */
if (iout < szbuf)
buffer[iout] = '%';
iout++;
}
if (iout < szbuf)
buffer[iout] = spec[1];
iout++;
} else if (val != NULL) {
/* substitution of the value */
while (*val) {
if (iout < szbuf)
buffer[iout] = *val;
iout++;
val++;
}
}
spec += 2;
}
}
/* standardize the found item*/
if (inf == iout)
val = NULL; /* empty key item */
else {
/* set zero ended key */
val = &buffer[inf];
if (iout < szbuf)
buffer[iout] = 0;
iout++;
}
/* record the value */
if (derived_key)
derived_key->keys[ikey] = val;
}
return iout;
}
/**
* Implementation of the AT-agent callback
*
* @param name name of the agent (not used, should be "@")
* @param agent_closure closure of the agent (not used)
* @param key the original searched key
* @param value the value found (string after @:)
* @param query the query identifer for replying or subquerying
* @return 0 in case of success or -errno like negative error code
*/
static
int
agent_at_cb(
const char *name,
void *agent_closure,
const data_key_t *key,
const char *value,
cynagora_query_t *query
) {
data_key_t atkey;
char *block;
size_t size;
/* compute the length */
size = parse(value, key, NULL, NULL, 0);
/* alloc the length locally */
block = alloca(size);
/* initialize the derived key */
parse(value, key, &atkey, block, size);
/* ask for the derived key */
return cyn_query_subquery_async(query, (on_result_cb_t*)cyn_query_reply, query, &atkey);
}
/* see agent-at.h */
int
agent_at_activate(
) {
return cyn_agent_add("@", agent_at_cb, 0);
}
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