2 This file is part of GNUnet
3 (C) 2004, 2005, 2006, 2007, 2009, 2010 Christian Grothoff (and other contributing authors)
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6 it under the terms of the GNU General Public License as published
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13 General Public License for more details.
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22 * @file datacache/datacache.c
23 * @brief datacache API implementation
24 * @author Christian Grothoff
27 #include "gnunet_util_lib.h"
28 #include "gnunet_datacache_lib.h"
29 #include "gnunet_statistics_service.h"
30 #include "gnunet_datacache_plugin.h"
33 #define LOG(kind,...) GNUNET_log_from (kind, "datacache", __VA_ARGS__)
35 #define LOG_STRERROR_FILE(kind,op,fn) GNUNET_log_from_strerror_file (kind, "datacache", op, fn)
38 * Internal state of the datacache library.
40 struct GNUNET_DATACACHE_Handle
44 * Bloomfilter to quickly tell if we don't have the content.
46 struct GNUNET_CONTAINER_BloomFilter *filter;
51 const struct GNUNET_CONFIGURATION_Handle *cfg;
54 * Opaque handle for the statistics service.
56 struct GNUNET_STATISTICS_Handle *stats;
59 * Configuration section to use.
64 * API of the transport as returned by the plugin's
65 * initialization function.
67 struct GNUNET_DATACACHE_PluginFunctions *api;
70 * Short name for the plugin (i.e. "sqlite").
75 * Name of the library (i.e. "gnunet_plugin_datacache_sqlite").
80 * Name for the bloom filter file.
85 * Environment provided to our plugin.
87 struct GNUNET_DATACACHE_PluginEnvironment env;
90 * How much space is in use right now?
92 unsigned long long utilization;
98 * Function called by plugins to notify the datacache
99 * about content deletions.
102 * @param key key of the content that was deleted
103 * @param size number of bytes that were made available
106 env_delete_notify (void *cls, const GNUNET_HashCode * key, size_t size)
108 struct GNUNET_DATACACHE_Handle *h = cls;
110 LOG (GNUNET_ERROR_TYPE_DEBUG, "Content under key `%s' discarded\n",
112 GNUNET_assert (h->utilization >= size);
113 h->utilization -= size;
114 GNUNET_CONTAINER_bloomfilter_remove (h->filter, key);
115 GNUNET_STATISTICS_update (h->stats, gettext_noop ("# bytes stored"), -size,
121 * Create a data cache.
123 * @param cfg configuration to use
124 * @param section section in the configuration that contains our options
125 * @return handle to use to access the service
127 struct GNUNET_DATACACHE_Handle *
128 GNUNET_DATACACHE_create (const struct GNUNET_CONFIGURATION_Handle *cfg,
131 unsigned int bf_size;
132 unsigned long long quota;
133 struct GNUNET_DATACACHE_Handle *ret;
138 GNUNET_CONFIGURATION_get_value_size (cfg, section, "QUOTA", "a))
140 LOG (GNUNET_ERROR_TYPE_ERROR,
141 _("No `%s' specified for `%s' in configuration!\n"), "QUOTA", section);
145 GNUNET_CONFIGURATION_get_value_string (cfg, section, "DATABASE", &name))
147 LOG (GNUNET_ERROR_TYPE_ERROR,
148 _("No `%s' specified for `%s' in configuration!\n"), "DATABASE",
152 bf_size = quota / 32; /* 8 bit per entry, 1 bit per 32 kb in DB */
154 ret = GNUNET_malloc (sizeof (struct GNUNET_DATACACHE_Handle));
155 ret->bloom_name = GNUNET_DISK_mktemp ("gnunet-datacachebloom");
156 if (NULL != ret->bloom_name)
158 ret->filter = GNUNET_CONTAINER_bloomfilter_load (ret->bloom_name, quota / 1024, /* 8 bit per entry in DB, expect 1k entries */
161 if (NULL == ret->filter)
163 ret->filter = GNUNET_CONTAINER_bloomfilter_init (NULL, bf_size, 5); /* approx. 3% false positives at max use */
165 if (NULL == ret->filter)
168 GNUNET_free (ret->bloom_name);
172 ret->stats = GNUNET_STATISTICS_create ("datacache", cfg);
173 ret->section = GNUNET_strdup (section);
175 ret->env.delete_notify = &env_delete_notify;
176 ret->env.section = ret->section;
178 ret->env.delete_notify = &env_delete_notify;
179 ret->env.quota = quota;
180 LOG (GNUNET_ERROR_TYPE_INFO, _("Loading `%s' datacache plugin\n"), name);
181 GNUNET_asprintf (&libname, "libgnunet_plugin_datacache_%s", name);
182 ret->short_name = name;
183 ret->lib_name = libname;
184 ret->api = GNUNET_PLUGIN_load (libname, &ret->env);
185 if (ret->api == NULL)
187 LOG (GNUNET_ERROR_TYPE_ERROR,
188 _("Failed to load datacache plugin for `%s'\n"), name);
189 GNUNET_DATACACHE_destroy (ret);
197 * Destroy a data cache (and free associated resources).
199 * @param h handle to the datastore
202 GNUNET_DATACACHE_destroy (struct GNUNET_DATACACHE_Handle *h)
204 if (h->filter != NULL)
205 GNUNET_CONTAINER_bloomfilter_free (h->filter);
207 GNUNET_break (NULL == GNUNET_PLUGIN_unload (h->lib_name, h->api));
208 GNUNET_free (h->lib_name);
209 GNUNET_free (h->short_name);
210 GNUNET_free (h->section);
211 if (h->bloom_name != NULL)
213 if (0 != UNLINK (h->bloom_name))
214 GNUNET_log_from_strerror_file (GNUNET_ERROR_TYPE_WARNING, "datacache",
215 "unlink", h->bloom_name);
216 GNUNET_free (h->bloom_name);
218 GNUNET_STATISTICS_destroy (h->stats, GNUNET_NO);
224 * Store an item in the datastore.
226 * @param h handle to the datacache
227 * @param key key to store data under
228 * @param size number of bytes in data
229 * @param data data to store
230 * @param type type of the value
231 * @param discard_time when to discard the value in any case
232 * @return GNUNET_OK on success, GNUNET_SYSERR on error (full, etc.)
235 GNUNET_DATACACHE_put (struct GNUNET_DATACACHE_Handle *h,
236 const GNUNET_HashCode * key, size_t size,
237 const char *data, enum GNUNET_BLOCK_Type type,
238 struct GNUNET_TIME_Absolute discard_time)
242 used = h->api->put (h->api->cls, key, size, data, type, discard_time);
246 return GNUNET_SYSERR;
248 LOG (GNUNET_ERROR_TYPE_DEBUG, "Stored data under key `%s' in cache\n",
250 GNUNET_STATISTICS_update (h->stats, gettext_noop ("# bytes stored"), size,
252 GNUNET_CONTAINER_bloomfilter_add (h->filter, key);
253 while (h->utilization + used > h->env.quota)
254 GNUNET_assert (GNUNET_OK == h->api->del (h->api->cls));
255 h->utilization += used;
261 * Iterate over the results for a particular key
264 * @param h handle to the datacache
265 * @param key what to look up
266 * @param type entries of which type are relevant?
267 * @param iter maybe NULL (to just count)
268 * @param iter_cls closure for iter
269 * @return the number of results found
272 GNUNET_DATACACHE_get (struct GNUNET_DATACACHE_Handle *h,
273 const GNUNET_HashCode * key, enum GNUNET_BLOCK_Type type,
274 GNUNET_DATACACHE_Iterator iter, void *iter_cls)
276 GNUNET_STATISTICS_update (h->stats, gettext_noop ("# requests received"), 1,
278 LOG (GNUNET_ERROR_TYPE_DEBUG, "Processing request for key `%s'\n",
280 if (GNUNET_OK != GNUNET_CONTAINER_bloomfilter_test (h->filter, key))
282 GNUNET_STATISTICS_update (h->stats,
284 ("# requests filtered by bloom filter"), 1,
286 LOG (GNUNET_ERROR_TYPE_DEBUG, "Bloomfilter filters request for key `%s'\n",
288 return 0; /* can not be present */
290 return h->api->get (h->api->cls, key, type, iter, iter_cls);
295 /* end of datacache_api.c */