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/*
This file is part of GNUnet
(C) 2006, 2009 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 2, 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., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.
*/
/**
* @file include/gnunet_datacache_plugin.h
* @brief API for database backends for the datacache
* @author Christian Grothoff
*/
#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 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 size number of bytes in data
* @param data data to store
* @param type type of the value
* @param discard_time when to discard the value in any case
* @return 0 on error, number of bytes used otherwise
*/
size_t (*put) (void *cls, const GNUNET_HashCode * key, size_t size,
const char *data, enum GNUNET_BLOCK_Type type,
struct GNUNET_TIME_Absolute discard_time);
/**
* Iterate over the results for a particular key
* in the datastore.
*
* @param cls closure (internal context for the plugin)
* @param key
* @param type entries of which type are relevant?
* @param iter maybe NULL (to just count)
* @param iter_cls closure for iter
* @return the number of results found
*/
unsigned int (*get) (void *cls, const 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);
};
#if 0 /* keep Emacsens' auto-indent happy */
{
#endif
#ifdef __cplusplus
}
#endif
/* end of gnunet_datacache_plugin.h */
#endif
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