guacamole-spice-protocol/src/guacd/proc-map.c

203 lines
5.2 KiB
C

/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.
*/
#include "config.h"
#include "common/list.h"
#include "proc.h"
#include "proc-map.h"
#include <guacamole/client.h>
#include <stdlib.h>
#include <string.h>
/**
* Returns a hash code based on the given connection ID.
*
* @param str
* The string containing the connection ID.
*
* @return
* A reasonably well-distributed hash code for the given string.
*/
static unsigned int __guacd_client_hash(const char* str) {
unsigned int hash_value = 0;
int c;
/* Apply each character in string to the hash code */
while ((c = *(str++)))
hash_value = hash_value * 65599 + c;
return hash_value;
}
/**
* Locates the bucket corresponding to the hash code indicated by the given id,
* where the hash code is dictated by __guacd_client_hash(). Each bucket is an
* instance of guac_common_list.
*
* @param map
* The map to retrieve the hash bucket from.
*
* @param id
* The ID whose hash code determines the bucket being retrieved.
*
* @return
* The bucket corresponding to the hash code for the given ID, represented
* by a guac_common_list.
*/
static guac_common_list* __guacd_proc_find_bucket(guacd_proc_map* map,
const char* id) {
const int index = __guacd_client_hash(id) % GUACD_PROC_MAP_BUCKETS;
return map->__buckets[index];
}
/**
* Given a bucket of guacd_proc instances, returns the guacd_proc having the
* guac_client with the given ID, or NULL if no such client is stored.
*
* @param bucket
* The bucket of guacd_proc instances to search, represented as a
* guac_common_list.
*
* @param id
* The ID of the guac_client whose corresponding guacd_proc instance should
* be located within the bucket.
*
* @return
* The guac_common_list_element containing the guacd_proc instance
* corresponding to the guac_client having the given ID, or NULL of no such
* element exists.
*/
static guac_common_list_element* __guacd_proc_find(guac_common_list* bucket,
const char* id) {
guac_common_list_element* current = bucket->head;
/* Search for matching element within bucket */
while (current != NULL) {
/* Check connection ID */
guacd_proc* proc = (guacd_proc*) current->data;
if (strcmp(proc->client->connection_id, id) == 0)
break;
current = current->next;
}
return current;
}
guacd_proc_map* guacd_proc_map_alloc() {
guacd_proc_map* map = malloc(sizeof(guacd_proc_map));
guac_common_list** current;
int i;
/* Init all buckets */
current = map->__buckets;
for (i=0; i<GUACD_PROC_MAP_BUCKETS; i++) {
*current = guac_common_list_alloc();
current++;
}
return map;
}
int guacd_proc_map_add(guacd_proc_map* map, guacd_proc* proc) {
const char* identifier = proc->client->connection_id;
guac_common_list* bucket = __guacd_proc_find_bucket(map, identifier);
guac_common_list_element* found;
/* Retrieve corresponding element, if any */
guac_common_list_lock(bucket);
found = __guacd_proc_find(bucket, identifier);
/* If no such element, we can add the new client successfully */
if (found == NULL) {
guac_common_list_add(bucket, proc);
guac_common_list_unlock(bucket);
return 0;
}
/* Otherwise, fail - already exists */
guac_common_list_unlock(bucket);
return 1;
}
guacd_proc* guacd_proc_map_retrieve(guacd_proc_map* map, const char* id) {
guacd_proc* proc;
guac_common_list* bucket = __guacd_proc_find_bucket(map, id);
guac_common_list_element* found;
/* Retrieve corresponding element, if any */
guac_common_list_lock(bucket);
found = __guacd_proc_find(bucket, id);
/* If no such element, fail */
if (found == NULL) {
guac_common_list_unlock(bucket);
return NULL;
}
proc = (guacd_proc*) found->data;
guac_common_list_unlock(bucket);
return proc;
}
guacd_proc* guacd_proc_map_remove(guacd_proc_map* map, const char* id) {
guacd_proc* proc;
guac_common_list* bucket = __guacd_proc_find_bucket(map, id);
guac_common_list_element* found;
/* Retrieve corresponding element, if any */
guac_common_list_lock(bucket);
found = __guacd_proc_find(bucket, id);
/* If no such element, fail */
if (found == NULL) {
guac_common_list_unlock(bucket);
return NULL;
}
proc = (guacd_proc*) found->data;
guac_common_list_remove(bucket, found);
guac_common_list_unlock(bucket);
return proc;
}