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22 * @author Florian Dold
23 * @author Christian Grothoff
26 * Two-peer set operations
28 * @defgroup set Set service
29 * Two-peer set operations
31 * @see [Documentation](https://gnunet.org/set-subsystem)
36 #ifndef GNUNET_SET_SERVICE_H
37 #define GNUNET_SET_SERVICE_H
42 #if 0 /* keep Emacsens' auto-indent happy */
47 #include "gnunet_common.h"
48 #include "gnunet_time_lib.h"
49 #include "gnunet_configuration_lib.h"
53 * Maximum size of a context message for set operation requests.
55 #define GNUNET_SET_CONTEXT_MESSAGE_MAX_SIZE ((1<<16) - 1024)
59 * Opaque handle to a set.
61 struct GNUNET_SET_Handle;
64 * Opaque handle to a set operation request from another peer.
66 struct GNUNET_SET_Request;
69 * Opaque handle to a listen operation.
71 struct GNUNET_SET_ListenHandle;
74 * Opaque handle to a set operation.
76 struct GNUNET_SET_OperationHandle;
80 * The operation that a set set supports.
82 enum GNUNET_SET_OperationType
85 * A purely local set that does not support any operation.
87 GNUNET_SET_OPERATION_NONE,
90 * Set intersection, only return elements that are in both sets.
92 GNUNET_SET_OPERATION_INTERSECTION,
95 * Set union, return all elements that are in at least one of the sets.
97 GNUNET_SET_OPERATION_UNION
102 * Status for the result callback
104 enum GNUNET_SET_Status
107 * Everything went ok, we are transmitting an element of the
108 * result (in set, or to be removed from set, depending on
109 * the `enum GNUNET_SET_ResultMode`).
112 * #GNUNET_SET_RESULT_FULL,
113 * #GNUNET_SET_RESULT_ADDED,
114 * #GNUNET_SET_RESULT_REMOVED,
116 GNUNET_SET_STATUS_OK,
119 * Element should be added to the result set
120 * of the local peer, i.e. the local peer is
121 * missing an element.
123 * Only applies to #GNUNET_SET_RESULT_SYMMETRIC
125 GNUNET_SET_STATUS_ADD_LOCAL,
128 * Element should be added to the result set
129 * of the remove peer, i.e. the remote peer is
130 * missing an element.
132 * Only applies to #GNUNET_SET_RESULT_SYMMETRIC
134 GNUNET_SET_STATUS_ADD_REMOTE,
137 * The other peer refused to to the operation with us,
138 * or something went wrong.
140 GNUNET_SET_STATUS_FAILURE,
143 * Success, all elements have been returned (but the other peer
144 * might still be receiving some from us, so we are not done). Only
145 * used during UNION operation.
147 GNUNET_SET_STATUS_HALF_DONE,
150 * Success, all elements have been sent (and received).
152 GNUNET_SET_STATUS_DONE
157 * The way results are given to the client.
159 enum GNUNET_SET_ResultMode
162 * Client gets every element in the resulting set.
164 * Only supported for set intersection.
166 GNUNET_SET_RESULT_FULL,
169 * Client gets notified of the required changes
170 * for both the local and the remote set.
172 * Only supported for set
174 GNUNET_SET_RESULT_SYMMETRIC,
177 * Client gets only elements that have been removed from the set.
179 * Only supported for set intersection.
181 GNUNET_SET_RESULT_REMOVED,
184 * Client gets only elements that have been removed from the set.
186 * Only supported for set union.
188 GNUNET_SET_RESULT_ADDED
193 * Element stored in a set.
195 struct GNUNET_SET_Element
198 * Number of bytes in the buffer pointed to by data.
203 * Application-specific element type.
205 uint16_t element_type;
208 * Actual data of the element
215 * Continuation used for some of the set operations
220 (*GNUNET_SET_Continuation) (void *cls);
224 * Callback for set operation results. Called for each element
228 * @param element a result element, only valid if status is #GNUNET_SET_STATUS_OK
229 * @param status see `enum GNUNET_SET_Status`
232 (*GNUNET_SET_ResultIterator) (void *cls,
233 const struct GNUNET_SET_Element *element,
234 enum GNUNET_SET_Status status);
237 * Iterator for set elements.
240 * @param element the current element, NULL if all elements have been
242 * @return #GNUNET_YES to continue iterating, #GNUNET_NO to stop.
245 (*GNUNET_SET_ElementIterator) (void *cls,
246 const struct GNUNET_SET_Element *element);
250 * Called when another peer wants to do a set operation with the
251 * local peer. If a listen error occurs, the @a request is NULL.
254 * @param other_peer the other peer
255 * @param context_msg message with application specific information from
257 * @param request request from the other peer (never NULL), use GNUNET_SET_accept()
258 * to accept it, otherwise the request will be refused
259 * Note that we can't just return value from the listen callback,
260 * as it is also necessary to specify the set we want to do the
261 * operation with, whith sometimes can be derived from the context
262 * message. It's necessary to specify the timeout.
265 (*GNUNET_SET_ListenCallback) (void *cls,
266 const struct GNUNET_PeerIdentity *other_peer,
267 const struct GNUNET_MessageHeader *context_msg,
268 struct GNUNET_SET_Request *request);
273 (*GNUNET_SET_CopyReadyCallback) (void *cls,
274 struct GNUNET_SET_Handle *copy);
278 * Create an empty set, supporting the specified operation.
280 * @param cfg configuration to use for connecting to the
282 * @param op operation supported by the set
283 * Note that the operation has to be specified
284 * beforehand, as certain set operations need to maintain
285 * data structures spefific to the operation
286 * @return a handle to the set
288 struct GNUNET_SET_Handle *
289 GNUNET_SET_create (const struct GNUNET_CONFIGURATION_Handle *cfg,
290 enum GNUNET_SET_OperationType op);
294 * Add an element to the given set.
295 * After the element has been added (in the sense of being
296 * transmitted to the set service), @a cont will be called.
297 * Calls to #GNUNET_SET_add_element can be queued
299 * @param set set to add element to
300 * @param element element to add to the set
301 * @param cont continuation called after the element has been added
302 * @param cont_cls closure for @a cont
303 * @return #GNUNET_OK on success, #GNUNET_SYSERR if the
304 * set is invalid (e.g. the set service crashed)
307 GNUNET_SET_add_element (struct GNUNET_SET_Handle *set,
308 const struct GNUNET_SET_Element *element,
309 GNUNET_SET_Continuation cont,
314 * Remove an element to the given set.
315 * After the element has been removed (in the sense of the
316 * request being transmitted to the set service), cont will be called.
317 * Calls to remove_element can be queued
319 * @param set set to remove element from
320 * @param element element to remove from the set
321 * @param cont continuation called after the element has been removed
322 * @param cont_cls closure for @a cont
323 * @return #GNUNET_OK on success, #GNUNET_SYSERR if the
324 * set is invalid (e.g. the set service crashed)
327 GNUNET_SET_remove_element (struct GNUNET_SET_Handle *set,
328 const struct GNUNET_SET_Element *element,
329 GNUNET_SET_Continuation cont,
334 GNUNET_SET_copy_lazy (struct GNUNET_SET_Handle *set,
335 GNUNET_SET_CopyReadyCallback cb,
340 * Destroy the set handle, and free all associated resources.
341 * Iterations must have completed (or be explicitly canceled)
342 * before destroying the corresponding set. Operations may
343 * still be pending when a set is destroyed.
345 * @param set set to destroy
348 GNUNET_SET_destroy (struct GNUNET_SET_Handle *set);
352 * Prepare a set operation to be evaluated with another peer.
353 * The evaluation will not start until the client provides
354 * a local set with GNUNET_SET_commit().
356 * @param other_peer peer with the other set
357 * @param app_id hash for the application using the set
358 * @param context_msg additional information for the request
359 * @param result_mode specified how results will be returned,
360 * see `enum GNUNET_SET_ResultMode`.
361 * @param result_cb called on error or success
362 * @param result_cls closure for @a result_cb
363 * @return a handle to cancel the operation
365 struct GNUNET_SET_OperationHandle *
366 GNUNET_SET_prepare (const struct GNUNET_PeerIdentity *other_peer,
367 const struct GNUNET_HashCode *app_id,
368 const struct GNUNET_MessageHeader *context_msg,
369 enum GNUNET_SET_ResultMode result_mode,
370 GNUNET_SET_ResultIterator result_cb,
375 * Wait for set operation requests for the given application ID.
376 * If the connection to the set service is lost, the listener is
377 * re-created transparently with exponential backoff.
379 * @param cfg configuration to use for connecting to
381 * @param operation operation we want to listen for
382 * @param app_id id of the application that handles set operation requests
383 * @param listen_cb called for each incoming request matching the operation
385 * @param listen_cls handle for @a listen_cb
386 * @return a handle that can be used to cancel the listen operation
388 struct GNUNET_SET_ListenHandle *
389 GNUNET_SET_listen (const struct GNUNET_CONFIGURATION_Handle *cfg,
390 enum GNUNET_SET_OperationType op_type,
391 const struct GNUNET_HashCode *app_id,
392 GNUNET_SET_ListenCallback listen_cb,
397 * Cancel the given listen operation. After calling cancel, the
398 * listen callback for this listen handle will not be called again.
400 * @param lh handle for the listen operation
403 GNUNET_SET_listen_cancel (struct GNUNET_SET_ListenHandle *lh);
407 * Accept a request we got via GNUNET_SET_listen(). Must be called during
408 * GNUNET_SET_listen(), as the `struct GNUNET_SET_Request` becomes invalid
410 * Call GNUNET_SET_commit() to provide the local set to use for the operation,
411 * and to begin the exchange with the remote peer.
413 * @param request request to accept
414 * @param result_mode specified how results will be returned,
415 * see `enum GNUNET_SET_ResultMode`.
416 * @param result_cb callback for the results
417 * @param result_cls closure for @a result_cb
418 * @return a handle to cancel the operation
420 struct GNUNET_SET_OperationHandle *
421 GNUNET_SET_accept (struct GNUNET_SET_Request *request,
422 enum GNUNET_SET_ResultMode result_mode,
423 GNUNET_SET_ResultIterator result_cb,
428 * Commit a set to be used with a set operation.
429 * This function is called once we have fully constructed
430 * the set that we want to use for the operation. At this
431 * time, the P2P protocol can then begin to exchange the
432 * set information and call the result callback with the
433 * result information.
435 * @param oh handle to the set operation
436 * @param set the set to use for the operation
437 * @return #GNUNET_OK on success, #GNUNET_SYSERR if the
438 * set is invalid (e.g. the set service crashed)
441 GNUNET_SET_commit (struct GNUNET_SET_OperationHandle *oh,
442 struct GNUNET_SET_Handle *set);
446 * Cancel the given set operation. May not be called after the
447 * operation's `GNUNET_SET_ResultIterator` has been called with a
448 * status that indicates error, timeout or done.
450 * @param oh set operation to cancel
453 GNUNET_SET_operation_cancel (struct GNUNET_SET_OperationHandle *oh);
457 * Iterate over all elements in the given set.
458 * Note that this operation involves transferring every element of the set
459 * from the service to the client, and is thus costly.
460 * Only one iteration per set may be active at the same time.
462 * @param set the set to iterate over
463 * @param iter the iterator to call for each element
464 * @param iter_cls closure for @a iter
465 * @return #GNUNET_YES if the iteration started successfuly,
466 * #GNUNET_NO if another iteration was still active,
467 * #GNUNET_SYSERR if the set is invalid (e.g. the server crashed, disconnected)
470 GNUNET_SET_iterate (struct GNUNET_SET_Handle *set,
471 GNUNET_SET_ElementIterator iter,
475 * Stop iteration over all elements in the given set. Can only
476 * be called before the iteration has "naturally" completed its
479 * @param set the set to stop iterating over
482 GNUNET_SET_iterate_cancel (struct GNUNET_SET_Handle *set);
485 * Create a copy of an element. The copy
486 * must be GNUNET_free-d by the caller.
488 * @param element the element to copy
489 * @return the copied element
491 struct GNUNET_SET_Element *
492 GNUNET_SET_element_dup (const struct GNUNET_SET_Element *element);
495 * Hash a set element.
497 * @param element the element that should be hashed
498 * @param ret_hash a pointer to where the hash of @a element
502 GNUNET_SET_element_hash (const struct GNUNET_SET_Element *element, struct GNUNET_HashCode *ret_hash);
505 #if 0 /* keep Emacsens' auto-indent happy */
514 /** @} */ /* end of group */