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- /*
- This file is part of GNUnet
- Copyright (C) 2009, 2011 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
- */
- /**
- * @author Christian Grothoff
- *
- * @file
- * API for the database backend plugins.
- *
- * @defgroup datastore-plugin Data Store service plugin API
- * API for the database backend plugins.
- * @{
- */
- #ifndef PLUGIN_DATASTORE_H
- #define PLUGIN_DATASTORE_H
- #include "gnunet_block_lib.h"
- #include "gnunet_configuration_lib.h"
- #include "gnunet_datastore_service.h"
- #include "gnunet_statistics_service.h"
- #include "gnunet_scheduler_lib.h"
- /**
- * How many bytes of overhead will we assume per entry
- * in any DB (for reservations)?
- */
- #define GNUNET_DATASTORE_ENTRY_OVERHEAD 256
- /**
- * Function invoked to notify service of disk utilization
- * changes.
- *
- * @param cls closure
- * @param delta change in disk utilization,
- * 0 for "reset to empty"
- */
- typedef void
- (*GNUNET_DATASTORE_DiskUtilizationChange) (void *cls,
- int delta);
- /**
- * 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_DATASTORE_PluginEnvironment
- {
- /**
- * Configuration to use.
- */
- const struct GNUNET_CONFIGURATION_Handle *cfg;
- /**
- * Function to call on disk utilization change.
- */
- GNUNET_DATASTORE_DiskUtilizationChange duc;
- /**
- * Closure.
- */
- void *cls;
- };
- /**
- * An processor over a set of items stored in the datastore.
- *
- * @param cls closure
- * @param key key for the content
- * @param size number of bytes in data
- * @param data content stored
- * @param type type of the content
- * @param priority priority of the content
- * @param anonymity anonymity-level for the content
- * @param replication replication-level for the content
- * @param expiration expiration time for the content
- * @param uid unique identifier for the datum
- * @return #GNUNET_OK to keep the item
- * #GNUNET_NO to delete the item
- */
- typedef int
- (*PluginDatumProcessor) (void *cls,
- const struct GNUNET_HashCode *key,
- uint32_t size,
- const void *data,
- enum GNUNET_BLOCK_Type type,
- uint32_t priority,
- uint32_t anonymity,
- uint32_t replication,
- struct GNUNET_TIME_Absolute expiration,
- uint64_t uid);
- /**
- * Get an estimate of how much space the database is
- * currently using.
- *
- * NB: estimate is an output parameter because emscripten cannot handle
- * returning 64-bit integers from dynamically loaded modules.
- *
- * @param cls closure
- * @param estimate location to store estimate
- * @return number of bytes used on disk
- */
- typedef void
- (*PluginEstimateSize) (void *cls,
- unsigned long long *estimate);
- /**
- * Put continuation.
- *
- * @param cls closure
- * @param key key for the item stored
- * @param size size of the item stored
- * @param status #GNUNET_OK if inserted, #GNUNET_NO if updated,
- * or #GNUNET_SYSERROR if error
- * @param msg error message on error
- */
- typedef void
- (*PluginPutCont) (void *cls,
- const struct GNUNET_HashCode *key,
- uint32_t size,
- int status,
- const char *msg);
- /**
- * Store an item in the datastore. If the item is already present,
- * the priorities and replication levels are summed up and the higher
- * expiration time and lower anonymity level is used.
- *
- * @param cls closure
- * @param key key for the item
- * @param absent true if the key was not found in the bloom filter
- * @param size number of bytes in @a data
- * @param data content stored
- * @param type type of the content
- * @param priority priority of the content
- * @param anonymity anonymity-level for the content
- * @param replication replication-level for the content
- * @param expiration expiration time for the content
- * @param cont continuation called with success or failure status
- * @param cont_cls continuation closure for @a cont
- */
- typedef void
- (*PluginPut) (void *cls,
- const struct GNUNET_HashCode *key,
- bool absent,
- uint32_t size,
- const void *data,
- enum GNUNET_BLOCK_Type type,
- uint32_t priority,
- uint32_t anonymity,
- uint32_t replication,
- struct GNUNET_TIME_Absolute expiration,
- PluginPutCont cont,
- void *cont_cls);
- /**
- * An processor over a set of keys stored in the datastore.
- *
- * @param cls closure
- * @param key key in the data store, if NULL iteration is finished
- * @param count how many values are stored under this key in the datastore
- */
- typedef void
- (*PluginKeyProcessor) (void *cls,
- const struct GNUNET_HashCode *key,
- unsigned int count);
- /**
- * Get all of the keys in the datastore.
- *
- * @param cls closure
- * @param proc function to call on each key
- * @param proc_cls closure for @a proc
- */
- typedef void
- (*PluginGetKeys) (void *cls,
- PluginKeyProcessor proc,
- void *proc_cls);
- /**
- * Get one of the results for a particular key in the datastore.
- *
- * @param cls closure
- * @param next_uid return the result with lowest uid >= next_uid
- * @param random if true, return a random result instead of using next_uid
- * @param key maybe NULL (to match all entries)
- * @param type entries of which type are relevant?
- * Use 0 for any type.
- * @param proc function to call on the matching value;
- * will be called with NULL if nothing matches
- * @param proc_cls closure for @a proc
- */
- typedef void
- (*PluginGetKey) (void *cls,
- uint64_t next_uid,
- bool random,
- const struct GNUNET_HashCode *key,
- enum GNUNET_BLOCK_Type type,
- PluginDatumProcessor proc,
- void *proc_cls);
- /**
- * Remove continuation.
- *
- * @param cls closure
- * @param key key for the content removed
- * @param size number of bytes removed
- * @param status #GNUNET_OK if removed, #GNUNET_NO if not found,
- * or #GNUNET_SYSERROR if error
- * @param msg error message on error
- */
- typedef void
- (*PluginRemoveCont) (void *cls,
- const struct GNUNET_HashCode *key,
- uint32_t size,
- int status,
- const char *msg);
- /**
- * Remove a particular key in the datastore.
- *
- * @param cls closure
- * @param key key for the content
- * @param size number of bytes in data
- * @param data content stored
- * @param cont continuation called with success or failure status
- * @param cont_cls continuation closure for @a cont
- */
- typedef void
- (*PluginRemoveKey) (void *cls,
- const struct GNUNET_HashCode *key,
- uint32_t size,
- const void *data,
- PluginRemoveCont cont,
- void *cont_cls);
- /**
- * Get a random item (additional constraints may apply depending on
- * the specific implementation). Calls @a proc with all values ZERO or
- * NULL if no item applies, otherwise @a proc is called once and only
- * once with an item.
- *
- * @param cls closure
- * @param proc function to call the value (once only).
- * @param proc_cls closure for @a proc
- */
- typedef void
- (*PluginGetRandom) (void *cls,
- PluginDatumProcessor proc,
- void *proc_cls);
- /**
- * Select a single item from the datastore (among those applicable).
- *
- * @param cls closure
- * @param next_uid return the result with lowest uid >= next_uid
- * @param type entries of which type should be considered?
- * Must not be zero (ANY).
- * @param proc function to call on the matching value;
- * will be called with NULL if no value matches
- * @param proc_cls closure for @a proc
- */
- typedef void
- (*PluginGetType) (void *cls,
- uint64_t next_uid,
- enum GNUNET_BLOCK_Type type,
- PluginDatumProcessor proc,
- void *proc_cls);
- /**
- * Drop database.
- *
- * @param cls closure
- */
- typedef void
- (*PluginDrop) (void *cls);
- /**
- * Each plugin is required to return a pointer to a struct of this
- * type as the return value from its entry point.
- */
- struct GNUNET_DATASTORE_PluginFunctions
- {
- /**
- * Closure to use for all of the following callbacks
- * (except "next_request").
- */
- void *cls;
- /**
- * Calculate the current on-disk size of the SQ store. Estimates
- * are fine, if that's the only thing available.
- */
- PluginEstimateSize estimate_size;
- /**
- * Function to store an item in the datastore.
- */
- PluginPut put;
- /**
- * Get a particular datum matching a given hash from the datastore.
- */
- PluginGetKey get_key;
- /**
- * Get datum (of the specified type) with anonymity level zero.
- */
- PluginGetType get_zero_anonymity;
- /**
- * Function to get a random item with high replication score from
- * the database, lowering the item's replication score. Returns a
- * single random item from those with the highest replication
- * counters. The item's replication counter is decremented by one
- * IF it was positive before.
- */
- PluginGetRandom get_replication;
- /**
- * Function to get a random expired item or, if none are expired,
- * either the oldest entry or one with a low priority (depending
- * on what was efficiently implementable).
- */
- PluginGetRandom get_expiration;
- /**
- * Delete the database. The next operation is
- * guaranteed to be unloading of the module.
- */
- PluginDrop drop;
- /**
- * Iterate over all keys in the database.
- */
- PluginGetKeys get_keys;
- /**
- * Function to remove an item from the database.
- */
- PluginRemoveKey remove_key;
- };
- #endif
- /** @} */ /* end of group */
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