gnunet-android

gnunet_datacache_lib.h (5496B)

---

 /*
      This file is part of GNUnet
      Copyright (C) 2006, 2009, 2015, 2022 GNUnet e.V.
 
      GNUnet is free software: you can redistribute it and/or modify it
      under the terms of the GNU Affero General Public License as published
      by the Free Software Foundation, either version 3 of the License,
      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
      Affero General Public License for more details.
 
      You should have received a copy of the GNU Affero General Public License
      along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
      SPDX-License-Identifier: AGPL3.0-or-later
  */
 
 /**
  * @addtogroup dht_libs  DHT and support libraries
  * @{
  *
  * @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"
 #include "gnunet_dht_service.h"
 
 #ifdef __cplusplus
 extern "C"
 {
 #if 0                           /* keep Emacsens' auto-indent happy */
 }
 #endif
 #endif
 
 
 /**
  * Information about a block stored in the datacache.
  */
 struct GNUNET_DATACACHE_Block
 {
   /**
    * Key of the block.
    */
   struct GNUNET_HashCode key;
 
   /**
    * When does the block expire?
    */
   struct GNUNET_TIME_Absolute expiration_time;
 
   /**
    * If the path was truncated, this is the peer
    * ID at which the path was truncated.
    */
   struct GNUNET_PeerIdentity trunc_peer;
 
   /**
    * PUT path taken by the block, array of peer identities.
    */
   const struct GNUNET_DHT_PathElement *put_path;
 
   /**
    * Actual block data.
    */
   const void *data;
 
   /**
    * Number of bytes in @a data.
    */
   size_t data_size;
 
   /**
    * Length of the @e put_path array.
    */
   unsigned int put_path_length;
 
   /**
    * Type of the block.
    */
   enum GNUNET_BLOCK_Type type;
 
   /**
    * Options for routing for the block.
    */
   enum GNUNET_DHT_RouteOption ro;
 };
 
 
 /**
  * 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 block a block from the datacache
  * @return #GNUNET_OK to continue iterating, #GNUNET_SYSERR to abort
  */
 typedef enum GNUNET_GenericReturnValue
 (*GNUNET_DATACACHE_Iterator)(void *cls,
                              const struct GNUNET_DATACACHE_Block *block);
 
 
 /**
  * Store an item in the datacache.
  *
  * @param h handle to the datacache
  * @param xor_distance how close is the block's key to our pid?
  * @param block actual block data to store
  * @return #GNUNET_OK on success, #GNUNET_SYSERR on error, #GNUNET_NO if duplicate
  */
 enum GNUNET_GenericReturnValue
 GNUNET_DATACACHE_put (struct GNUNET_DATACACHE_Handle *h,
                       uint32_t xor_distance,
                       const struct GNUNET_DATACACHE_Block *block);
 
 
 /**
  * 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);
 
 
 /**
  * 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 type entries of which type are relevant?
  * @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,
                               enum GNUNET_BLOCK_Type type,
                               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 */
 
 /** @} */ /* end of group addition */