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3 Copyright (C) 2013, 2014 Christian Grothoff (and other contributing authors)
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22 * @file include/gnunet_set_service.h
23 * @brief two-peer set operations
24 * @author Florian Dold
25 * @author Christian Grothoff
28 #ifndef GNUNET_SET_SERVICE_H
29 #define GNUNET_SET_SERVICE_H
34 #if 0 /* keep Emacsens' auto-indent happy */
39 #include "gnunet_common.h"
40 #include "gnunet_time_lib.h"
41 #include "gnunet_configuration_lib.h"
45 * Maximum size of a context message for set operation requests.
47 #define GNUNET_SET_CONTEXT_MESSAGE_MAX_SIZE ((1<<16) - 1024)
51 * Opaque handle to a set.
53 struct GNUNET_SET_Handle;
56 * Opaque handle to a set operation request from another peer.
58 struct GNUNET_SET_Request;
61 * Opaque handle to a listen operation.
63 struct GNUNET_SET_ListenHandle;
66 * Opaque handle to a set operation.
68 struct GNUNET_SET_OperationHandle;
72 * The operation that a set set supports.
74 enum GNUNET_SET_OperationType
77 * A purely local set that does not support any operation.
79 GNUNET_SET_OPERATION_NONE,
82 * Set intersection, only return elements that are in both sets.
84 GNUNET_SET_OPERATION_INTERSECTION,
87 * Set union, return all elements that are in at least one of the sets.
89 GNUNET_SET_OPERATION_UNION
94 * Status for the result callback
96 enum GNUNET_SET_Status
99 * Everything went ok, we are transmitting an element of the
100 * result (in set, or to be removed from set, depending on
101 * the `enum GNUNET_SET_ResultMode`).
103 GNUNET_SET_STATUS_OK,
106 * The other peer refused to to the operation with us,
107 * or something went wrong.
109 GNUNET_SET_STATUS_FAILURE,
112 * Success, all elements have been returned (but the other peer
113 * might still be receiving some from us, so we are not done). Only
114 * used during UNION operation.
116 GNUNET_SET_STATUS_HALF_DONE,
119 * Success, all elements have been sent (and received).
121 GNUNET_SET_STATUS_DONE
126 * The way results are given to the client.
128 enum GNUNET_SET_ResultMode
131 * Client gets every element in the resulting set.
133 GNUNET_SET_RESULT_FULL,
136 * Client gets only elements that have been added to the set.
137 * Only works with set union.
139 GNUNET_SET_RESULT_ADDED,
142 * Client gets only elements that have been removed from the set.
143 * Only works with set intersection.
145 GNUNET_SET_RESULT_REMOVED
150 * Element stored in a set.
152 struct GNUNET_SET_Element
155 * Number of bytes in the buffer pointed to by data.
160 * Application-specific element type.
162 uint16_t element_type;
165 * Actual data of the element
172 * Continuation used for some of the set operations
176 typedef void (*GNUNET_SET_Continuation) (void *cls);
180 * Callback for set operation results. Called for each element
184 * @param element a result element, only valid if status is #GNUNET_SET_STATUS_OK
185 * @param status see `enum GNUNET_SET_Status`
187 typedef void (*GNUNET_SET_ResultIterator) (void *cls,
188 const struct GNUNET_SET_Element *element,
189 enum GNUNET_SET_Status status);
192 * Iterator for set elements.
195 * @param element the current element, NULL if all elements have been
197 * @return #GNUNET_YES to continue iterating, #GNUNET_NO to stop.
199 typedef int (*GNUNET_SET_ElementIterator) (void *cls,
200 const struct GNUNET_SET_Element *element);
204 * Called when another peer wants to do a set operation with the
205 * local peer. If a listen error occurs, the @a request is NULL.
208 * @param other_peer the other peer
209 * @param context_msg message with application specific information from
211 * @param request request from the other peer (never NULL), use GNUNET_SET_accept()
212 * to accept it, otherwise the request will be refused
213 * Note that we can't just return value from the listen callback,
214 * as it is also necessary to specify the set we want to do the
215 * operation with, whith sometimes can be derived from the context
216 * message. It's necessary to specify the timeout.
219 (*GNUNET_SET_ListenCallback) (void *cls,
220 const struct GNUNET_PeerIdentity *other_peer,
221 const struct GNUNET_MessageHeader *context_msg,
222 struct GNUNET_SET_Request *request);
227 (*GNUNET_SET_CopyReadyCallback) (void *cls,
228 struct GNUNET_SET_Handle *copy);
232 * Create an empty set, supporting the specified operation.
234 * @param cfg configuration to use for connecting to the
236 * @param op operation supported by the set
237 * Note that the operation has to be specified
238 * beforehand, as certain set operations need to maintain
239 * data structures spefific to the operation
240 * @return a handle to the set
242 struct GNUNET_SET_Handle *
243 GNUNET_SET_create (const struct GNUNET_CONFIGURATION_Handle *cfg,
244 enum GNUNET_SET_OperationType op);
248 * Add an element to the given set.
249 * After the element has been added (in the sense of being
250 * transmitted to the set service), @a cont will be called.
251 * Calls to #GNUNET_SET_add_element can be queued
253 * @param set set to add element to
254 * @param element element to add to the set
255 * @param cont continuation called after the element has been added
256 * @param cont_cls closure for @a cont
257 * @return #GNUNET_OK on success, #GNUNET_SYSERR if the
258 * set is invalid (e.g. the set service crashed)
261 GNUNET_SET_add_element (struct GNUNET_SET_Handle *set,
262 const struct GNUNET_SET_Element *element,
263 GNUNET_SET_Continuation cont,
268 * Remove an element to the given set.
269 * After the element has been removed (in the sense of the
270 * request being transmitted to the set service), cont will be called.
271 * Calls to remove_element can be queued
273 * @param set set to remove element from
274 * @param element element to remove from the set
275 * @param cont continuation called after the element has been removed
276 * @param cont_cls closure for @a cont
277 * @return #GNUNET_OK on success, #GNUNET_SYSERR if the
278 * set is invalid (e.g. the set service crashed)
281 GNUNET_SET_remove_element (struct GNUNET_SET_Handle *set,
282 const struct GNUNET_SET_Element *element,
283 GNUNET_SET_Continuation cont,
288 GNUNET_SET_copy_lazy (struct GNUNET_SET_Handle *set,
289 GNUNET_SET_CopyReadyCallback cb,
294 * Destroy the set handle, and free all associated resources.
295 * Iterations must have completed (or be explicitly canceled)
296 * before destroying the corresponding set. Operations may
297 * still be pending when a set is destroyed.
299 * @param set set to destroy
302 GNUNET_SET_destroy (struct GNUNET_SET_Handle *set);
306 * Prepare a set operation to be evaluated with another peer.
307 * The evaluation will not start until the client provides
308 * a local set with GNUNET_SET_commit().
310 * @param other_peer peer with the other set
311 * @param app_id hash for the application using the set
312 * @param context_msg additional information for the request
313 * @param result_mode specified how results will be returned,
314 * see `enum GNUNET_SET_ResultMode`.
315 * @param result_cb called on error or success
316 * @param result_cls closure for @a result_cb
317 * @return a handle to cancel the operation
319 struct GNUNET_SET_OperationHandle *
320 GNUNET_SET_prepare (const struct GNUNET_PeerIdentity *other_peer,
321 const struct GNUNET_HashCode *app_id,
322 const struct GNUNET_MessageHeader *context_msg,
323 enum GNUNET_SET_ResultMode result_mode,
324 GNUNET_SET_ResultIterator result_cb,
329 * Wait for set operation requests for the given application ID.
330 * If the connection to the set service is lost, the listener is
331 * re-created transparently with exponential backoff.
333 * @param cfg configuration to use for connecting to
335 * @param operation operation we want to listen for
336 * @param app_id id of the application that handles set operation requests
337 * @param listen_cb called for each incoming request matching the operation
339 * @param listen_cls handle for @a listen_cb
340 * @return a handle that can be used to cancel the listen operation
342 struct GNUNET_SET_ListenHandle *
343 GNUNET_SET_listen (const struct GNUNET_CONFIGURATION_Handle *cfg,
344 enum GNUNET_SET_OperationType op_type,
345 const struct GNUNET_HashCode *app_id,
346 GNUNET_SET_ListenCallback listen_cb,
351 * Cancel the given listen operation. After calling cancel, the
352 * listen callback for this listen handle will not be called again.
354 * @param lh handle for the listen operation
357 GNUNET_SET_listen_cancel (struct GNUNET_SET_ListenHandle *lh);
361 * Accept a request we got via GNUNET_SET_listen(). Must be called during
362 * GNUNET_SET_listen(), as the `struct GNUNET_SET_Request` becomes invalid
364 * Call GNUNET_SET_commit() to provide the local set to use for the operation,
365 * and to begin the exchange with the remote peer.
367 * @param request request to accept
368 * @param result_mode specified how results will be returned,
369 * see `enum GNUNET_SET_ResultMode`.
370 * @param result_cb callback for the results
371 * @param result_cls closure for @a result_cb
372 * @return a handle to cancel the operation
374 struct GNUNET_SET_OperationHandle *
375 GNUNET_SET_accept (struct GNUNET_SET_Request *request,
376 enum GNUNET_SET_ResultMode result_mode,
377 GNUNET_SET_ResultIterator result_cb,
382 * Commit a set to be used with a set operation.
383 * This function is called once we have fully constructed
384 * the set that we want to use for the operation. At this
385 * time, the P2P protocol can then begin to exchange the
386 * set information and call the result callback with the
387 * result information.
389 * @param oh handle to the set operation
390 * @param set the set to use for the operation
391 * @return #GNUNET_OK on success, #GNUNET_SYSERR if the
392 * set is invalid (e.g. the set service crashed)
395 GNUNET_SET_commit (struct GNUNET_SET_OperationHandle *oh,
396 struct GNUNET_SET_Handle *set);
400 * Cancel the given set operation. May not be called after the
401 * operation's `GNUNET_SET_ResultIterator` has been called with a
402 * status that indicates error, timeout or done.
404 * @param oh set operation to cancel
407 GNUNET_SET_operation_cancel (struct GNUNET_SET_OperationHandle *oh);
411 * Iterate over all elements in the given set.
412 * Note that this operation involves transferring every element of the set
413 * from the service to the client, and is thus costly.
414 * Only one iteration per set may be active at the same time.
416 * @param set the set to iterate over
417 * @param iter the iterator to call for each element
418 * @param iter_cls closure for @a iter
419 * @return #GNUNET_YES if the iteration started successfuly,
420 * #GNUNET_NO if another iteration was still active,
421 * #GNUNET_SYSERR if the set is invalid (e.g. the server crashed, disconnected)
424 GNUNET_SET_iterate (struct GNUNET_SET_Handle *set,
425 GNUNET_SET_ElementIterator iter,
429 * Stop iteration over all elements in the given set. Can only
430 * be called before the iteration has "naturally" completed its
433 * @param set the set to stop iterating over
436 GNUNET_SET_iterate_cancel (struct GNUNET_SET_Handle *set);
439 #if 0 /* keep Emacsens' auto-indent happy */