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3 Copyright (C) 2006, 2009, 2015 GNUnet e.V.
5 GNUnet is free software: you can redistribute it and/or modify it
6 under the terms of the GNU Affero General Public License as published
7 by the Free Software Foundation, either version 3 of the License,
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10 GNUnet is distributed in the hope that it will be useful, but
11 WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Affero General Public License for more details.
15 You should have received a copy of the GNU Affero General Public License
16 along with this program. If not, see <http://www.gnu.org/licenses/>.
20 * @author Christian Grothoff
23 * API for database backends for the datacache
25 * @defgroup datacache-plugin Data Cache plugin API
26 * API for database backends for the datacache
29 #ifndef PLUGIN_DATACACHE_H
30 #define PLUGIN_DATACACHE_H
32 #include "gnunet_datacache_lib.h"
37 #if 0 /* keep Emacsens' auto-indent happy */
44 * Function called by plugins to notify the datacache
45 * about content deletions.
48 * @param key key of the content that was deleted
49 * @param size number of bytes that were made available
52 (*GNUNET_DATACACHE_DeleteNotifyCallback) (void *cls,
53 const struct GNUNET_HashCode *key,
58 * The datastore service will pass a pointer to a struct
59 * of this type as the first and only argument to the
60 * entry point of each datastore plugin.
62 struct GNUNET_DATACACHE_PluginEnvironment
66 * Configuration to use.
68 const struct GNUNET_CONFIGURATION_Handle *cfg;
71 * Configuration section to use.
76 * Closure to use for callbacks.
81 * Function to call whenever the plugin needs to
82 * discard content that it was asked to store.
84 GNUNET_DATACACHE_DeleteNotifyCallback delete_notify;
87 * How much space are we allowed to use?
89 unsigned long long quota;
95 * @brief struct returned by the initialization function of the plugin
97 struct GNUNET_DATACACHE_PluginFunctions
101 * Closure to pass to all plugin functions.
106 * Store an item in the datastore.
108 * @param cls closure (internal context for the plugin)
109 * @param key key to store the value under
110 * @param xor_distance how close is @a key to our PID?
111 * @param size number of bytes in @a data
112 * @param data data to store
113 * @param type type of the value
114 * @param discard_time when to discard the value in any case
115 * @param path_info_len number of entries in @a path_info
116 * @param path_info a path through the network
117 * @return 0 if duplicate, -1 on error, number of bytes used otherwise
119 ssize_t (*put) (void *cls,
120 const struct GNUNET_HashCode *key,
121 uint32_t xor_distance,
124 enum GNUNET_BLOCK_Type type,
125 struct GNUNET_TIME_Absolute discard_time,
126 unsigned int path_info_len,
127 const struct GNUNET_PeerIdentity *path_info);
130 * Iterate over the results for a particular key
133 * @param cls closure (internal context for the plugin)
134 * @param key key to look for
135 * @param type entries of which type are relevant?
136 * @param iter maybe NULL (to just count)
137 * @param iter_cls closure for @a iter
138 * @return the number of results found
140 unsigned int (*get) (void *cls,
141 const struct GNUNET_HashCode *key,
142 enum GNUNET_BLOCK_Type type,
143 GNUNET_DATACACHE_Iterator iter,
147 * Delete the entry with the lowest expiration value
148 * from the datacache right now.
150 * @param cls closure (internal context for the plugin)
151 * @return #GNUNET_OK on success, #GNUNET_SYSERR on error
153 int (*del) (void *cls);
156 * Return a random value from the datastore.
158 * @param cls closure (internal context for the plugin)
159 * @param iter maybe NULL (to just count)
160 * @param iter_cls closure for @a iter
161 * @return the number of results found (zero or one)
163 unsigned int (*get_random) (void *cls,
164 GNUNET_DATACACHE_Iterator iter,
169 * Iterate over the results that are "close" to a particular key in
170 * the datacache. "close" is defined as numerically larger than @a
171 * key (when interpreted as a circular address space), with small
174 * @param cls closure (internal context for the plugin)
175 * @param key area of the keyspace to look into
176 * @param num_results number of results that should be returned to @a iter
177 * @param iter maybe NULL (to just count)
178 * @param iter_cls closure for @a iter
179 * @return the number of results found
181 unsigned int (*get_closest) (void *cls,
182 const struct GNUNET_HashCode *key,
183 unsigned int num_results,
184 GNUNET_DATACACHE_Iterator iter,
190 #if 0 /* keep Emacsens' auto-indent happy */
199 /** @} */ /* end of group */