2 This file is part of GNUnet
3 Copyright (C) 2004, 2005, 2006, 2007, 2009, 2010, 2011 Christian Grothoff (and other contributing authors)
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22 * @file include/gnunet_datastore_service.h
23 * @brief API that can be used manage the
24 * datastore for files stored on a GNUnet node;
25 * note that the datastore is NOT responsible for
26 * on-demand encoding, that is achieved using
27 * a special kind of entry.
28 * @author Christian Grothoff
31 #ifndef GNUNET_DATASTORE_SERVICE_H
32 #define GNUNET_DATASTORE_SERVICE_H
34 #include "gnunet_util_lib.h"
35 #include "gnunet_block_lib.h"
40 #if 0 /* keep Emacsens' auto-indent happy */
48 struct GNUNET_DATASTORE_QueueEntry;
51 * Handle to the datastore service.
53 struct GNUNET_DATASTORE_Handle;
56 * Maximum size of a value that can be stored in the datastore.
58 #define GNUNET_DATASTORE_MAX_VALUE_SIZE 65536
61 * Connect to the datastore service.
63 * @param cfg configuration to use
64 * @return handle to use to access the service
66 struct GNUNET_DATASTORE_Handle *
67 GNUNET_DATASTORE_connect (const struct GNUNET_CONFIGURATION_Handle *cfg);
71 * Disconnect from the datastore service (and free
72 * associated resources).
74 * @param h handle to the datastore
75 * @param drop set to GNUNET_YES to delete all data in datastore (!)
78 GNUNET_DATASTORE_disconnect (struct GNUNET_DATASTORE_Handle *h, int drop);
82 * Continuation called to notify client about result of the
86 * @param success #GNUNET_SYSERR on failure (including timeout/queue drop)
87 * #GNUNET_NO if content was already there
88 * #GNUNET_YES (or other positive value) on success
89 * @param min_expiration minimum expiration time required for 0-priority content to be stored
90 * by the datacache at this time, zero for unknown, forever if we have no
91 * space for 0-priority content
92 * @param msg NULL on success, otherwise an error message
94 typedef void (*GNUNET_DATASTORE_ContinuationWithStatus) (void *cls,
96 struct GNUNET_TIME_Absolute min_expiration,
101 * Reserve space in the datastore. This function should be used
102 * to avoid "out of space" failures during a longer sequence of "put"
103 * operations (for example, when a file is being inserted).
105 * @param h handle to the datastore
106 * @param amount how much space (in bytes) should be reserved (for content only)
107 * @param entries how many entries will be created (to calculate per-entry overhead)
108 * @param cont continuation to call when done; "success" will be set to
109 * a positive reservation value if space could be reserved.
110 * @param cont_cls closure for @a cont
111 * @return NULL if the entry was not queued, otherwise a handle that can be used to
112 * cancel; note that even if NULL is returned, the callback will be invoked
113 * (or rather, will already have been invoked)
115 struct GNUNET_DATASTORE_QueueEntry *
116 GNUNET_DATASTORE_reserve (struct GNUNET_DATASTORE_Handle *h,
119 GNUNET_DATASTORE_ContinuationWithStatus cont,
124 * Store an item in the datastore. If the item is already present,
125 * the priorities and replication values are summed up and the higher
126 * expiration time and lower anonymity level is used.
128 * @param h handle to the datastore
129 * @param rid reservation ID to use (from "reserve"); use 0 if no
130 * prior reservation was made
131 * @param key key for the value
132 * @param size number of bytes in data
133 * @param data content stored
134 * @param type type of the content
135 * @param priority priority of the content
136 * @param anonymity anonymity-level for the content
137 * @param replication how often should the content be replicated to other peers?
138 * @param expiration expiration time for the content
139 * @param queue_priority ranking of this request in the priority queue
140 * @param max_queue_size at what queue size should this request be dropped
141 * (if other requests of higher priority are in the queue)
142 * @param timeout timeout for the operation
143 * @param cont continuation to call when done
144 * @param cont_cls closure for @a cont
145 * @return NULL if the entry was not queued, otherwise a handle that can be used to
146 * cancel; note that even if NULL is returned, the callback will be invoked
147 * (or rather, will already have been invoked)
149 struct GNUNET_DATASTORE_QueueEntry *
150 GNUNET_DATASTORE_put (struct GNUNET_DATASTORE_Handle *h, uint32_t rid,
151 const struct GNUNET_HashCode *key, size_t size,
152 const void *data, enum GNUNET_BLOCK_Type type,
153 uint32_t priority, uint32_t anonymity,
154 uint32_t replication,
155 struct GNUNET_TIME_Absolute expiration,
156 unsigned int queue_priority, unsigned int max_queue_size,
157 struct GNUNET_TIME_Relative timeout,
158 GNUNET_DATASTORE_ContinuationWithStatus cont,
163 * Signal that all of the data for which a reservation was made has
164 * been stored and that whatever excess space might have been reserved
165 * can now be released.
167 * @param h handle to the datastore
168 * @param rid reservation ID (value of "success" in original continuation
169 * from the "reserve" function).
170 * @param queue_priority ranking of this request in the priority queue
171 * @param max_queue_size at what queue size should this request be dropped
172 * (if other requests of higher priority are in the queue)
173 * @param queue_priority ranking of this request in the priority queue
174 * @param max_queue_size at what queue size should this request be dropped
175 * (if other requests of higher priority are in the queue)
176 * @param timeout how long to wait at most for a response
177 * @param cont continuation to call when done
178 * @param cont_cls closure for @a cont
179 * @return NULL if the entry was not queued, otherwise a handle that can be used to
180 * cancel; note that even if NULL is returned, the callback will be invoked
181 * (or rather, will already have been invoked)
183 struct GNUNET_DATASTORE_QueueEntry *
184 GNUNET_DATASTORE_release_reserve (struct GNUNET_DATASTORE_Handle *h,
185 uint32_t rid, unsigned int queue_priority,
186 unsigned int max_queue_size,
187 struct GNUNET_TIME_Relative timeout,
188 GNUNET_DATASTORE_ContinuationWithStatus cont,
193 * Update a value in the datastore.
195 * @param h handle to the datastore
196 * @param uid identifier for the value
197 * @param priority how much to increase the priority of the value
198 * @param expiration new expiration value should be MAX of existing and this argument
199 * @param queue_priority ranking of this request in the priority queue
200 * @param max_queue_size at what queue size should this request be dropped
201 * (if other requests of higher priority are in the queue)
202 * @param timeout how long to wait at most for a response
203 * @param cont continuation to call when done
204 * @param cont_cls closure for @a cont
205 * @return NULL if the entry was not queued, otherwise a handle that can be used to
206 * cancel; note that even if NULL is returned, the callback will be invoked
207 * (or rather, will already have been invoked)
209 struct GNUNET_DATASTORE_QueueEntry *
210 GNUNET_DATASTORE_update (struct GNUNET_DATASTORE_Handle *h,
213 struct GNUNET_TIME_Absolute expiration,
214 unsigned int queue_priority,
215 unsigned int max_queue_size,
216 struct GNUNET_TIME_Relative timeout,
217 GNUNET_DATASTORE_ContinuationWithStatus cont,
222 * Explicitly remove some content from the database. @a cont will be
223 * called with status #GNUNET_OK if content was removed, #GNUNET_NO if
224 * no matching entry was found and #GNUNET_SYSERR on all other types
227 * @param h handle to the datastore
228 * @param key key for the value
229 * @param size number of bytes in @a data
230 * @param data content stored
231 * @param queue_priority ranking of this request in the priority queue
232 * @param max_queue_size at what queue size should this request be dropped
233 * (if other requests of higher priority are in the queue)
234 * @param timeout how long to wait at most for a response
235 * @param cont continuation to call when done
236 * @param cont_cls closure for @a cont
237 * @return NULL if the entry was not queued, otherwise a handle that can be used to
238 * cancel; note that even if NULL is returned, the callback will be invoked
239 * (or rather, will already have been invoked)
241 struct GNUNET_DATASTORE_QueueEntry *
242 GNUNET_DATASTORE_remove (struct GNUNET_DATASTORE_Handle *h,
243 const struct GNUNET_HashCode *key,
246 unsigned int queue_priority,
247 unsigned int max_queue_size,
248 struct GNUNET_TIME_Relative timeout,
249 GNUNET_DATASTORE_ContinuationWithStatus cont,
254 * Process a datum that was stored in the datastore.
257 * @param key key for the content
258 * @param size number of bytes in data
259 * @param data content stored
260 * @param type type of the content
261 * @param priority priority of the content
262 * @param anonymity anonymity-level for the content
263 * @param expiration expiration time for the content
264 * @param uid unique identifier for the datum;
265 * maybe 0 if no unique identifier is available
268 (*GNUNET_DATASTORE_DatumProcessor) (void *cls,
269 const struct GNUNET_HashCode *key,
272 enum GNUNET_BLOCK_Type type,
275 struct GNUNET_TIME_Absolute expiration,
280 * Get a result for a particular key from the datastore. The processor
281 * will only be called once.
283 * @param h handle to the datastore
284 * @param offset offset of the result (modulo num-results); set to
285 * a random 64-bit value initially; then increment by
286 * one each time; detect that all results have been found by uid
287 * being again the first uid ever returned.
288 * @param key maybe NULL (to match all entries)
289 * @param type desired type, 0 for any
290 * @param queue_priority ranking of this request in the priority queue
291 * @param max_queue_size at what queue size should this request be dropped
292 * (if other requests of higher priority are in the queue)
293 * @param timeout how long to wait at most for a response
294 * @param proc function to call on a matching value;
295 * or with a NULL value if no datum matches
296 * @param proc_cls closure for @a proc
297 * @return NULL if the entry was not queued, otherwise a handle that can be used to
300 struct GNUNET_DATASTORE_QueueEntry *
301 GNUNET_DATASTORE_get_key (struct GNUNET_DATASTORE_Handle *h,
303 const struct GNUNET_HashCode *key,
304 enum GNUNET_BLOCK_Type type,
305 unsigned int queue_priority,
306 unsigned int max_queue_size,
307 struct GNUNET_TIME_Relative timeout,
308 GNUNET_DATASTORE_DatumProcessor proc,
313 * Get a single zero-anonymity value from the datastore.
314 * Note that some implementations can ignore the 'offset' and
315 * instead return a random zero-anonymity value. In that case,
316 * detecting the wrap-around based on a repeating UID is at best
319 * @param h handle to the datastore
320 * @param offset offset of the result (modulo num-results); set to
321 * a random 64-bit value initially; then increment by
322 * one each time; detect that all results have been found by uid
323 * being again the first uid ever returned.
324 * @param queue_priority ranking of this request in the priority queue
325 * @param max_queue_size at what queue size should this request be dropped
326 * (if other requests of higher priority are in the queue)
327 * @param timeout how long to wait at most for a response
328 * @param type allowed type for the operation (never zero)
329 * @param proc function to call on a random value; it
330 * will be called once with a value (if available)
331 * or with NULL if none value exists.
332 * @param proc_cls closure for proc
333 * @return NULL if the entry was not queued, otherwise a handle that can be used to
336 struct GNUNET_DATASTORE_QueueEntry *
337 GNUNET_DATASTORE_get_zero_anonymity (struct GNUNET_DATASTORE_Handle *h,
339 unsigned int queue_priority,
340 unsigned int max_queue_size,
341 struct GNUNET_TIME_Relative timeout,
342 enum GNUNET_BLOCK_Type type,
343 GNUNET_DATASTORE_DatumProcessor proc,
348 * Get a random value from the datastore for content replication.
349 * Returns a single, random value among those with the highest
350 * replication score, lowering positive replication scores by one for
351 * the chosen value (if only content with a replication score exists,
352 * a random value is returned and replication scores are not changed).
354 * @param h handle to the datastore
355 * @param queue_priority ranking of this request in the priority queue
356 * @param max_queue_size at what queue size should this request be dropped
357 * (if other requests of higher priority are in the queue)
358 * @param timeout how long to wait at most for a response
359 * @param proc function to call on a random value; it
360 * will be called once with a value (if available)
361 * and always once with a value of NULL.
362 * @param proc_cls closure for @a proc
363 * @return NULL if the entry was not queued, otherwise a handle that can be used to
366 struct GNUNET_DATASTORE_QueueEntry *
367 GNUNET_DATASTORE_get_for_replication (struct GNUNET_DATASTORE_Handle *h,
368 unsigned int queue_priority,
369 unsigned int max_queue_size,
370 struct GNUNET_TIME_Relative timeout,
371 GNUNET_DATASTORE_DatumProcessor proc,
377 * Cancel a datastore operation. The final callback from the
378 * operation must not have been done yet.
380 * @param qe operation to cancel
383 GNUNET_DATASTORE_cancel (struct GNUNET_DATASTORE_QueueEntry *qe);
386 #if 0 /* keep Emacsens' auto-indent happy */
393 /* end of gnunet_datastore_service.h */