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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
- * datacache API
- *
- * @defgroup datacache Data Cache library
- * Simple, transient hash table of bounded size with content expiration.
- *
- * In contrast to the sqstore there is
- * no prioritization, deletion or iteration.
- * All of the data is discarded when the peer shuts down!
- *
- * @{
- */
- #ifndef GNUNET_DATACACHE_LIB_H
- #define GNUNET_DATACACHE_LIB_H
- #include "gnunet_util_lib.h"
- #include "gnunet_block_lib.h"
- #ifdef __cplusplus
- extern "C"
- {
- #if 0 /* keep Emacsens' auto-indent happy */
- }
- #endif
- #endif
- /**
- * Handle to the cache.
- */
- struct GNUNET_DATACACHE_Handle;
- /**
- * Create a data cache.
- *
- * @param cfg configuration to use
- * @param section section in the configuration that contains our options
- * @return handle to use to access the service
- */
- struct GNUNET_DATACACHE_Handle *
- GNUNET_DATACACHE_create (const struct GNUNET_CONFIGURATION_Handle *cfg,
- const char *section);
- /**
- * Destroy a data cache (and free associated resources).
- *
- * @param h handle to the datastore
- */
- void
- GNUNET_DATACACHE_destroy (struct GNUNET_DATACACHE_Handle *h);
- /**
- * An iterator over a set of items stored in the datacache.
- *
- * @param cls closure
- * @param key key for the content
- * @param data_size number of bytes in @a data
- * @param data content stored
- * @param type type of the content
- * @param exp when will the content expire?
- * @param path_info_len number of entries in @a path_info
- * @param path_info a path through the network
- * @return #GNUNET_OK to continue iterating, #GNUNET_SYSERR to abort
- */
- typedef int
- (*GNUNET_DATACACHE_Iterator) (void *cls,
- const struct GNUNET_HashCode *key,
- size_t data_size,
- const char *data,
- enum GNUNET_BLOCK_Type type,
- struct GNUNET_TIME_Absolute exp,
- unsigned int path_info_len,
- const struct GNUNET_PeerIdentity *path_info);
- /**
- * Store an item in the datacache.
- *
- * @param h handle to the datacache
- * @param key key to store data under
- * @param data_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 #GNUNET_OK on success, #GNUNET_SYSERR on error, #GNUNET_NO if duplicate
- */
- int
- GNUNET_DATACACHE_put (struct GNUNET_DATACACHE_Handle *h,
- const struct GNUNET_HashCode *key,
- size_t data_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 datacache.
- *
- * @param h handle to the datacache
- * @param key what to look up
- * @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
- GNUNET_DATACACHE_get (struct GNUNET_DATACACHE_Handle *h,
- const struct GNUNET_HashCode *key,
- enum GNUNET_BLOCK_Type type,
- GNUNET_DATACACHE_Iterator iter,
- void *iter_cls);
- /**
- * Obtain a random element from the datacache.
- *
- * @param h handle to the datacache
- * @param iter maybe NULL (to just count)
- * @param iter_cls closure for @a iter
- * @return the number of results found (zero or 1)
- */
- unsigned int
- GNUNET_DATACACHE_get_random (struct GNUNET_DATACACHE_Handle *h,
- 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 h handle to the datacache
- * @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
- GNUNET_DATACACHE_get_closest (struct GNUNET_DATACACHE_Handle *h,
- 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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