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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 queue_priority ranking of this request in the priority queue
109 * @param max_queue_size at what queue size should this request be dropped
110 * (if other requests of higher priority are in the queue)
111 * @param timeout how long to wait at most for a response (or before dying in queue)
112 * @param cont continuation to call when done; "success" will be set to
113 * a positive reservation value if space could be reserved.
114 * @param cont_cls closure for cont
115 * @return NULL if the entry was not queued, otherwise a handle that can be used to
116 * cancel; note that even if NULL is returned, the callback will be invoked
117 * (or rather, will already have been invoked)
119 struct GNUNET_DATASTORE_QueueEntry *
120 GNUNET_DATASTORE_reserve (struct GNUNET_DATASTORE_Handle *h, uint64_t amount,
121 uint32_t entries, unsigned int queue_priority,
122 unsigned int max_queue_size,
123 struct GNUNET_TIME_Relative timeout,
124 GNUNET_DATASTORE_ContinuationWithStatus cont,
129 * Store an item in the datastore. If the item is already present,
130 * the priorities and replication values are summed up and the higher
131 * expiration time and lower anonymity level is used.
133 * @param h handle to the datastore
134 * @param rid reservation ID to use (from "reserve"); use 0 if no
135 * prior reservation was made
136 * @param key key for the value
137 * @param size number of bytes in data
138 * @param data content stored
139 * @param type type of the content
140 * @param priority priority of the content
141 * @param anonymity anonymity-level for the content
142 * @param replication how often should the content be replicated to other peers?
143 * @param expiration expiration time for the content
144 * @param queue_priority ranking of this request in the priority queue
145 * @param max_queue_size at what queue size should this request be dropped
146 * (if other requests of higher priority are in the queue)
147 * @param timeout timeout for the operation
148 * @param cont continuation to call when done
149 * @param cont_cls closure for cont
150 * @return NULL if the entry was not queued, otherwise a handle that can be used to
151 * cancel; note that even if NULL is returned, the callback will be invoked
152 * (or rather, will already have been invoked)
154 struct GNUNET_DATASTORE_QueueEntry *
155 GNUNET_DATASTORE_put (struct GNUNET_DATASTORE_Handle *h, uint32_t rid,
156 const GNUNET_HashCode * key, size_t size,
157 const void *data, enum GNUNET_BLOCK_Type type,
158 uint32_t priority, uint32_t anonymity,
159 uint32_t replication,
160 struct GNUNET_TIME_Absolute expiration,
161 unsigned int queue_priority, unsigned int max_queue_size,
162 struct GNUNET_TIME_Relative timeout,
163 GNUNET_DATASTORE_ContinuationWithStatus cont,
168 * Signal that all of the data for which a reservation was made has
169 * been stored and that whatever excess space might have been reserved
170 * can now be released.
172 * @param h handle to the datastore
173 * @param rid reservation ID (value of "success" in original continuation
174 * from the "reserve" function).
175 * @param queue_priority ranking of this request in the priority queue
176 * @param max_queue_size at what queue size should this request be dropped
177 * (if other requests of higher priority are in the queue)
178 * @param queue_priority ranking of this request in the priority queue
179 * @param max_queue_size at what queue size should this request be dropped
180 * (if other requests of higher priority are in the queue)
181 * @param timeout how long to wait at most for a response
182 * @param cont continuation to call when done
183 * @param cont_cls closure for cont
184 * @return NULL if the entry was not queued, otherwise a handle that can be used to
185 * cancel; note that even if NULL is returned, the callback will be invoked
186 * (or rather, will already have been invoked)
188 struct GNUNET_DATASTORE_QueueEntry *
189 GNUNET_DATASTORE_release_reserve (struct GNUNET_DATASTORE_Handle *h,
190 uint32_t rid, unsigned int queue_priority,
191 unsigned int max_queue_size,
192 struct GNUNET_TIME_Relative timeout,
193 GNUNET_DATASTORE_ContinuationWithStatus cont,
198 * Update a value in the datastore.
200 * @param h handle to the datastore
201 * @param uid identifier for the value
202 * @param priority how much to increase the priority of the value
203 * @param expiration new expiration value should be MAX of existing and this argument
204 * @param queue_priority ranking of this request in the priority queue
205 * @param max_queue_size at what queue size should this request be dropped
206 * (if other requests of higher priority are in the queue)
207 * @param timeout how long to wait at most for a response
208 * @param cont continuation to call when done
209 * @param cont_cls closure for cont
210 * @return NULL if the entry was not queued, otherwise a handle that can be used to
211 * cancel; note that even if NULL is returned, the callback will be invoked
212 * (or rather, will already have been invoked)
214 struct GNUNET_DATASTORE_QueueEntry *
215 GNUNET_DATASTORE_update (struct GNUNET_DATASTORE_Handle *h, uint64_t uid,
217 struct GNUNET_TIME_Absolute expiration,
218 unsigned int queue_priority,
219 unsigned int max_queue_size,
220 struct GNUNET_TIME_Relative timeout,
221 GNUNET_DATASTORE_ContinuationWithStatus cont,
226 * Explicitly remove some content from the database.
227 * The "cont"inuation will be called with status
228 * "GNUNET_OK" if content was removed, "GNUNET_NO"
229 * if no matching entry was found and "GNUNET_SYSERR"
230 * on all other types of errors.
232 * @param h handle to the datastore
233 * @param key key for the value
234 * @param size number of bytes in data
235 * @param data content stored
236 * @param queue_priority ranking of this request in the priority queue
237 * @param max_queue_size at what queue size should this request be dropped
238 * (if other requests of higher priority are in the queue)
239 * @param timeout how long to wait at most for a response
240 * @param cont continuation to call when done
241 * @param cont_cls closure for cont
242 * @return NULL if the entry was not queued, otherwise a handle that can be used to
243 * cancel; note that even if NULL is returned, the callback will be invoked
244 * (or rather, will already have been invoked)
246 struct GNUNET_DATASTORE_QueueEntry *
247 GNUNET_DATASTORE_remove (struct GNUNET_DATASTORE_Handle *h,
248 const GNUNET_HashCode * key, size_t size,
249 const void *data, unsigned int queue_priority,
250 unsigned int max_queue_size,
251 struct GNUNET_TIME_Relative timeout,
252 GNUNET_DATASTORE_ContinuationWithStatus cont,
257 * Process a datum that was stored in the datastore.
260 * @param key key for the content
261 * @param size number of bytes in data
262 * @param data content stored
263 * @param type type of the content
264 * @param priority priority of the content
265 * @param anonymity anonymity-level for the content
266 * @param expiration expiration time for the content
267 * @param uid unique identifier for the datum;
268 * maybe 0 if no unique identifier is available
270 typedef void (*GNUNET_DATASTORE_DatumProcessor) (void *cls,
271 const GNUNET_HashCode * key,
272 size_t size, const void *data,
273 enum GNUNET_BLOCK_Type type,
276 struct GNUNET_TIME_Absolute
277 expiration, uint64_t uid);
281 * Get a result for a particular key from the datastore. The processor
282 * will only be called once.
284 * @param h handle to the datastore
285 * @param offset offset of the result (modulo num-results); set to
286 * a random 64-bit value initially; then increment by
287 * one each time; detect that all results have been found by uid
288 * being again the first uid ever returned.
289 * @param key maybe NULL (to match all entries)
290 * @param type desired type, 0 for any
291 * @param queue_priority ranking of this request in the priority queue
292 * @param max_queue_size at what queue size should this request be dropped
293 * (if other requests of higher priority are in the queue)
294 * @param timeout how long to wait at most for a response
295 * @param proc function to call on each matching value;
296 * will be called once with a NULL value at the end
297 * @param proc_cls closure for proc
298 * @return NULL if the entry was not queued, otherwise a handle that can be used to
301 struct GNUNET_DATASTORE_QueueEntry *
302 GNUNET_DATASTORE_get_key (struct GNUNET_DATASTORE_Handle *h, uint64_t offset,
303 const 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, void *proc_cls);
312 * Get a single zero-anonymity value from the datastore.
313 * Note that some implementations can ignore the 'offset' and
314 * instead return a random zero-anonymity value. In that case,
315 * detecting the wrap-around based on a repeating UID is at best
318 * @param h handle to the datastore
319 * @param offset offset of the result (modulo num-results); set to
320 * a random 64-bit value initially; then increment by
321 * one each time; detect that all results have been found by uid
322 * being again the first uid ever returned.
323 * @param queue_priority ranking of this request in the priority queue
324 * @param max_queue_size at what queue size should this request be dropped
325 * (if other requests of higher priority are in the queue)
326 * @param timeout how long to wait at most for a response
327 * @param type allowed type for the operation (never zero)
328 * @param proc function to call on a random value; it
329 * will be called once with a value (if available)
330 * or with NULL if none value exists.
331 * @param proc_cls closure for proc
332 * @return NULL if the entry was not queued, otherwise a handle that can be used to
335 struct GNUNET_DATASTORE_QueueEntry *
336 GNUNET_DATASTORE_get_zero_anonymity (struct GNUNET_DATASTORE_Handle *h,
338 unsigned int queue_priority,
339 unsigned int max_queue_size,
340 struct GNUNET_TIME_Relative timeout,
341 enum GNUNET_BLOCK_Type type,
342 GNUNET_DATASTORE_DatumProcessor proc,
347 * Get a random value from the datastore for content replication.
348 * Returns a single, random value among those with the highest
349 * replication score, lowering positive replication scores by one for
350 * the chosen value (if only content with a replication score exists,
351 * a random value is returned and replication scores are not changed).
353 * @param h handle to the datastore
354 * @param queue_priority ranking of this request in the priority queue
355 * @param max_queue_size at what queue size should this request be dropped
356 * (if other requests of higher priority are in the queue)
357 * @param timeout how long to wait at most for a response
358 * @param proc function to call on a random value; it
359 * will be called once with a value (if available)
360 * and always once with a value of NULL.
361 * @param proc_cls closure for proc
362 * @return NULL if the entry was not queued, otherwise a handle that can be used to
365 struct GNUNET_DATASTORE_QueueEntry *
366 GNUNET_DATASTORE_get_for_replication (struct GNUNET_DATASTORE_Handle *h,
367 unsigned int queue_priority,
368 unsigned int max_queue_size,
369 struct GNUNET_TIME_Relative timeout,
370 GNUNET_DATASTORE_DatumProcessor proc,
376 * Cancel a datastore operation. The final callback from the
377 * operation must not have been done yet.
379 * @param qe operation to cancel
382 GNUNET_DATASTORE_cancel (struct GNUNET_DATASTORE_QueueEntry *qe);
385 #if 0 /* keep Emacsens' auto-indent happy */
392 /* end of gnunet_datastore_service.h */