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- /*
- This file is part of GNUnet
- Copyright (C) 2006, 2009, 2015 Christian Grothoff (and other contributing authors)
- GNUnet is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published
- by the Free Software Foundation; either version 3, or (at your
- option) any later version.
- GNUnet is distributed in the hope that it will be useful, but
- WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- General Public License for more details.
- You should have received a copy of the GNU General Public License
- along with GNUnet; see the file COPYING. If not, write to the
- Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
- Boston, MA 02110-1301, USA.
- */
- /**
- * @author Christian Grothoff
- *
- * @file
- * API for database backends for the datacache
- *
- * @defgroup datacache-plugin Data Cache plugin API
- * API for database backends for the datacache
- * @{
- */
- #ifndef PLUGIN_DATACACHE_H
- #define PLUGIN_DATACACHE_H
- #include "gnunet_datacache_lib.h"
- #ifdef __cplusplus
- extern "C"
- {
- #if 0 /* keep Emacsens' auto-indent happy */
- }
- #endif
- #endif
- /**
- * Function called by plugins to notify the datacache
- * about content deletions.
- *
- * @param cls closure
- * @param key key of the content that was deleted
- * @param size number of bytes that were made available
- */
- typedef void
- (*GNUNET_DATACACHE_DeleteNotifyCallback) (void *cls,
- const struct GNUNET_HashCode *key,
- size_t size);
- /**
- * The datastore service will pass a pointer to a struct
- * of this type as the first and only argument to the
- * entry point of each datastore plugin.
- */
- struct GNUNET_DATACACHE_PluginEnvironment
- {
- /**
- * Configuration to use.
- */
- const struct GNUNET_CONFIGURATION_Handle *cfg;
- /**
- * Configuration section to use.
- */
- const char *section;
- /**
- * Closure to use for callbacks.
- */
- void *cls;
- /**
- * Function to call whenever the plugin needs to
- * discard content that it was asked to store.
- */
- GNUNET_DATACACHE_DeleteNotifyCallback delete_notify;
- /**
- * How much space are we allowed to use?
- */
- unsigned long long quota;
- };
- /**
- * @brief struct returned by the initialization function of the plugin
- */
- struct GNUNET_DATACACHE_PluginFunctions
- {
- /**
- * Closure to pass to all plugin functions.
- */
- void *cls;
- /**
- * Store an item in the datastore.
- *
- * @param cls closure (internal context for the plugin)
- * @param key key to store the value under
- * @param size number of bytes in @a data
- * @param data data to store
- * @param type type of the value
- * @param discard_time when to discard the value in any case
- * @param path_info_len number of entries in @a path_info
- * @param path_info a path through the network
- * @return 0 if duplicate, -1 on error, number of bytes used otherwise
- */
- ssize_t (*put) (void *cls,
- const struct GNUNET_HashCode *key,
- size_t size,
- const char *data,
- enum GNUNET_BLOCK_Type type,
- struct GNUNET_TIME_Absolute discard_time,
- unsigned int path_info_len,
- const struct GNUNET_PeerIdentity *path_info);
- /**
- * Iterate over the results for a particular key
- * in the datastore.
- *
- * @param cls closure (internal context for the plugin)
- * @param key key to look for
- * @param type entries of which type are relevant?
- * @param iter maybe NULL (to just count)
- * @param iter_cls closure for @a iter
- * @return the number of results found
- */
- unsigned int (*get) (void *cls,
- const struct GNUNET_HashCode *key,
- enum GNUNET_BLOCK_Type type,
- GNUNET_DATACACHE_Iterator iter,
- void *iter_cls);
- /**
- * Delete the entry with the lowest expiration value
- * from the datacache right now.
- *
- * @param cls closure (internal context for the plugin)
- * @return #GNUNET_OK on success, #GNUNET_SYSERR on error
- */
- int (*del) (void *cls);
- /**
- * Return a random value from the datastore.
- *
- * @param cls closure (internal context for the plugin)
- * @param iter maybe NULL (to just count)
- * @param iter_cls closure for @a iter
- * @return the number of results found (zero or one)
- */
- unsigned int (*get_random) (void *cls,
- GNUNET_DATACACHE_Iterator iter,
- void *iter_cls);
- /**
- * Iterate over the results that are "close" to a particular key in
- * the datacache. "close" is defined as numerically larger than @a
- * key (when interpreted as a circular address space), with small
- * distance.
- *
- * @param cls closure (internal context for the plugin)
- * @param key area of the keyspace to look into
- * @param num_results number of results that should be returned to @a iter
- * @param iter maybe NULL (to just count)
- * @param iter_cls closure for @a iter
- * @return the number of results found
- */
- unsigned int (*get_closest) (void *cls,
- const struct GNUNET_HashCode *key,
- unsigned int num_results,
- GNUNET_DATACACHE_Iterator iter,
- void *iter_cls);
- };
- #if 0 /* keep Emacsens' auto-indent happy */
- {
- #endif
- #ifdef __cplusplus
- }
- #endif
- #endif
- /** @} */ /* end of group */
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