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3 (C) 2009, 2010 Christian Grothoff (and other contributing authors)
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22 * @file fs/gnunet-service-fs_drq.c
23 * @brief queueing of requests to the datastore service
24 * @author Christian Grothoff
27 #include "gnunet-service-fs_drq.h"
29 #define DEBUG_DRQ GNUNET_NO
32 * Signature of a function that is called whenever a datastore
33 * request can be processed (or an entry put on the queue times out).
36 * @param ok GNUNET_OK if DS is ready, GNUNET_SYSERR on timeout
38 typedef void (*RequestFunction)(void *cls,
43 * Doubly-linked list of our requests for the datastore.
45 struct DatastoreRequestQueue
49 * This is a doubly-linked list.
51 struct DatastoreRequestQueue *next;
54 * This is a doubly-linked list.
56 struct DatastoreRequestQueue *prev;
59 * Function to call for each entry.
61 GNUNET_DATASTORE_Iterator iter;
69 * Key we are doing the 'get' for.
74 * Timeout for this operation.
76 struct GNUNET_TIME_Absolute timeout;
79 * ID of task used for signaling timeout.
81 GNUNET_SCHEDULER_TaskIdentifier task;
84 * Datastore entry type we are doing the 'get' for.
89 * Is this request at the head of the queue irrespective of its
99 static struct GNUNET_SCHEDULER_Handle *sched;
104 static const struct GNUNET_CONFIGURATION_Handle *cfg;
107 * Head of request queue for the datastore, sorted by timeout.
109 static struct DatastoreRequestQueue *drq_head;
112 * Tail of request queue for the datastore.
114 static struct DatastoreRequestQueue *drq_tail;
117 * Our connection to the datastore.
119 static struct GNUNET_DATASTORE_Handle *dsh;
122 * Pointer to the currently actively running request,
123 * NULL if none is running.
125 static struct DatastoreRequestQueue *drq_running;
129 * Run the next DS request in our queue, we're done with the current
137 * Wrapper for the datastore get operation. Makes sure to trigger the
138 * next datastore operation in the queue once the operation is
141 * @param cls our 'struct DatastoreRequestQueue*'
142 * @param key key for the content
143 * @param size number of bytes in data
144 * @param data content stored
145 * @param type type of the content
146 * @param priority priority of the content
147 * @param anonymity anonymity-level for the content
148 * @param expiration expiration time for the content
149 * @param uid unique identifier for the datum;
150 * maybe 0 if no unique identifier is available
153 get_iterator (void *cls,
154 const GNUNET_HashCode * key,
160 struct GNUNET_TIME_Absolute
164 struct DatastoreRequestQueue *gc = cls;
166 if (gc->iter == NULL)
168 /* stop the iteration */
170 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
171 "Iteration terminated\n");
174 GNUNET_DATASTORE_get_next (dsh, GNUNET_NO);
180 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
181 "Iteration produced %u-byte result for `%s'\n",
185 gc->iter (gc->iter_cls,
186 key, size, data, type,
187 priority, anonymity, expiration, uid);
192 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
193 "Iteration completed\n");
195 GNUNET_assert (gc == drq_running);
204 * A datastore request can be run right now. Run it.
206 * @param cls closure (of type "struct DatastoreRequestQueue*")
207 * @param tc task context, unused
210 run_next_request (void *cls,
211 const struct GNUNET_SCHEDULER_TaskContext *tc)
213 struct DatastoreRequestQueue *gc = cls;
215 gc->task = GNUNET_SCHEDULER_NO_TASK;
217 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
218 "Running datastore request for `%s' of type %u\n",
219 GNUNET_h2s (&gc->key),
222 GNUNET_DATASTORE_get (dsh, &gc->key, gc->type,
225 GNUNET_TIME_absolute_get_remaining(gc->timeout));
230 * Run the next DS request in our queue, we're done with the current
236 struct DatastoreRequestQueue *e;
238 GNUNET_free_non_null (drq_running);
243 GNUNET_CONTAINER_DLL_remove (drq_head, drq_tail, e);
245 GNUNET_SCHEDULER_cancel (sched, e->task);
246 e->task = GNUNET_SCHEDULER_add_now (sched,
253 * A datastore request had to be timed out.
255 * @param cls closure (unused)
256 * @param tc task context, unused
259 timeout_ds_request (void *cls,
260 const struct GNUNET_SCHEDULER_TaskContext *tc)
262 struct DatastoreRequestQueue *e = cls;
265 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
266 "Datastore request timed out in queue before transmission\n");
268 e->task = GNUNET_SCHEDULER_NO_TASK;
269 GNUNET_CONTAINER_DLL_remove (drq_head, drq_tail, e);
271 e->iter (e->iter_cls,
272 NULL, 0, NULL, 0, 0, 0,
273 GNUNET_TIME_UNIT_ZERO_ABS, 0);
279 * Task run during shutdown.
285 shutdown_task (void *cls,
286 const struct GNUNET_SCHEDULER_TaskContext *tc)
288 struct DatastoreRequestQueue *drq;
291 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
292 "DRQ shutdown initiated\n");
294 GNUNET_assert (NULL != dsh);
295 GNUNET_DATASTORE_disconnect (dsh,
298 while (NULL != (drq = drq_head))
300 drq_head = drq->next;
301 GNUNET_SCHEDULER_cancel (sched, drq->task);
302 if (drq->iter != NULL)
303 drq->iter (drq->iter_cls,
304 NULL, 0, NULL, 0, 0, 0,
305 GNUNET_TIME_UNIT_ZERO_ABS, 0);
313 * Iterate over the results for a particular key
314 * in the datastore. The iterator will only be called
315 * once initially; if the first call did contain a
316 * result, further results can be obtained by calling
317 * "GNUNET_DATASTORE_get_next" with the given argument.
319 * @param key maybe NULL (to match all entries)
320 * @param type desired type, 0 for any
321 * @param iter function to call on each matching value;
322 * will be called once with a NULL value at the end
323 * @param iter_cls closure for iter
324 * @param timeout how long to wait at most for a response
325 * @param immediate should this be queued immediately at
326 * the head of the queue (irrespecitive of the timeout)?
328 struct DatastoreRequestQueue *
329 GNUNET_FS_drq_get (const GNUNET_HashCode * key,
331 GNUNET_DATASTORE_Iterator iter,
333 struct GNUNET_TIME_Relative timeout,
336 struct DatastoreRequestQueue *e;
337 struct DatastoreRequestQueue *bef;
340 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
341 "DRQ receives request for `%s' of type %u\n",
345 e = GNUNET_malloc (sizeof (struct DatastoreRequestQueue));
346 e->timeout = GNUNET_TIME_relative_to_absolute (timeout);
347 e->forced_head = immediate;
351 e->iter_cls = iter_cls;
352 e->timeout = GNUNET_TIME_relative_to_absolute (timeout);
353 if (GNUNET_YES == immediate)
355 /* local request, highest prio, put at head of queue
356 regardless of deadline */
362 while ( (NULL != bef) &&
363 (e->timeout.value < bef->timeout.value) &&
364 (GNUNET_YES != e->forced_head) )
367 GNUNET_CONTAINER_DLL_insert_after (drq_head, drq_tail, bef, e);
368 e->task = GNUNET_SCHEDULER_add_delayed (sched,
372 if (drq_running == NULL)
379 * Cancel the given operation.
381 * @param drq the queued operation (must not have been
385 GNUNET_FS_drq_get_cancel (struct DatastoreRequestQueue *drq)
388 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
389 "DRQ receives request cancellation request\n");
391 if (drq == drq_running)
393 /* 'DATASTORE_get' has already been started (and this call might
394 actually be be legal since it is possible that the client has
395 not yet received any calls to its the iterator; so we need to
396 cancel somehow; we do this by zeroing the 'iter' field, which
397 stops the iteration */
398 drq_running->iter = NULL;
402 GNUNET_CONTAINER_DLL_remove (drq_head, drq_tail, drq);
403 GNUNET_SCHEDULER_cancel (sched, drq->task);
410 * Function called to trigger obtaining the next result
411 * from the datastore.
413 * @param more GNUNET_YES to get more results, GNUNET_NO to abort
414 * iteration (with a final call to "iter" with key/data == NULL).
417 GNUNET_FS_drq_get_next (int more)
420 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
421 "DRQ receives request for next result (more is %d)\n",
424 GNUNET_DATASTORE_get_next (dsh, more);
429 * Closure for 'drq_remove_cont'.
433 struct GNUNET_DATASTORE_Handle *rmdsh;
434 GNUNET_DATASTORE_ContinuationWithStatus cont;
440 drq_remove_cont (void *cls,
444 struct RemoveContext *rc = cls;
446 rc->cont (rc->cont_cls,
449 GNUNET_DATASTORE_disconnect (rc->rmdsh, GNUNET_NO);
455 * Explicitly remove some content from the database.
456 * The "cont"inuation will be called with status
457 * "GNUNET_OK" if content was removed, "GNUNET_NO"
458 * if no matching entry was found and "GNUNET_SYSERR"
459 * on all other types of errors.
461 * @param key key for the value
462 * @param size number of bytes in data
463 * @param data content stored
464 * @param cont continuation to call when done
465 * @param cont_cls closure for cont
466 * @param timeout how long to wait at most for a response
469 GNUNET_FS_drq_remove (const GNUNET_HashCode *key,
470 uint32_t size, const void *data,
471 GNUNET_DATASTORE_ContinuationWithStatus cont,
473 struct GNUNET_TIME_Relative timeout)
475 struct GNUNET_DATASTORE_Handle *rmdsh;
476 struct RemoveContext *rc;
478 rmdsh = GNUNET_DATASTORE_connect (cfg,
485 _("Failed to connect to datastore"));
488 rc = GNUNET_malloc (sizeof (struct RemoveContext));
490 rc->cont_cls = cont_cls;
492 GNUNET_DATASTORE_remove (rmdsh, key, size, data,
499 * Setup datastore request queues.
501 * @param s scheduler to use
502 * @param c configuration to use
503 * @return GNUNET_OK on success
506 GNUNET_FS_drq_init (struct GNUNET_SCHEDULER_Handle *s,
507 const struct GNUNET_CONFIGURATION_Handle *c)
511 dsh = GNUNET_DATASTORE_connect (cfg,
515 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
516 _("Failed to connect to `%s' service.\n"),
518 return GNUNET_SYSERR;
520 GNUNET_SCHEDULER_add_delayed (sched,
521 GNUNET_TIME_UNIT_FOREVER_REL,
528 /* end of gnunet-service-fs_drq.c */