2 * Copyright (C) 2015, 2016, 2017 "IoT.bzh"
3 * Author "Fulup Ar Foll"
4 * Author José Bollo <jose.bollo@iot.bzh>
6 * Licensed under the Apache License, Version 2.0 (the "License");
7 * you may not use this file except in compliance with the License.
8 * You may obtain a copy of the License at
10 * http://www.apache.org/licenses/LICENSE-2.0
12 * Unless required by applicable law or agreed to in writing, software
13 * distributed under the License is distributed on an "AS IS" BASIS,
14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 * See the License for the specific language governing permissions and
16 * limitations under the License.
27 #include <json-c/json.h>
28 #include <afb/afb-event-itf.h>
37 * Structure for event listeners
39 struct afb_evt_listener {
41 /* chaining listeners */
42 struct afb_evt_listener *next;
44 /* interface for callbacks */
45 const struct afb_evt_itf *itf;
47 /* closure for the callback */
50 /* head of the list of events listened */
51 struct afb_evt_watch *watchs;
53 /* mutex of the listener */
54 pthread_mutex_t mutex;
56 /* count of reference to the listener */
61 * Structure for describing events
63 struct afb_evt_event {
66 struct afb_evt_event *next;
68 /* head of the list of listeners watching the event */
69 struct afb_evt_watch *watchs;
77 /* mutex of the event */
78 pthread_mutex_t mutex;
80 /* name of the event */
85 * Structure for associating events and listeners
87 struct afb_evt_watch {
90 struct afb_evt_event *event;
92 /* link to the next listener for the same event */
93 struct afb_evt_watch *next_by_event;
96 struct afb_evt_listener *listener;
98 /* link to the next event for the same listener */
99 struct afb_evt_watch *next_by_listener;
105 /* declare functions */
106 static int evt_broadcast(struct afb_evt_event *evt, struct json_object *obj);
107 static int evt_push(struct afb_evt_event *evt, struct json_object *obj);
108 static void evt_destroy(struct afb_evt_event *evt);
109 static const char *evt_name(struct afb_evt_event *evt);
111 /* the interface for events */
112 static struct afb_event_itf afb_evt_event_itf = {
113 .broadcast = (void*)evt_broadcast,
114 .push = (void*)evt_push,
115 .drop = (void*)evt_destroy,
116 .name = (void*)evt_name
119 /* head of the list of listeners */
120 static pthread_mutex_t listeners_mutex = PTHREAD_MUTEX_INITIALIZER;
121 static struct afb_evt_listener *listeners = NULL;
123 /* handling id of events */
124 static pthread_mutex_t events_mutex = PTHREAD_MUTEX_INITIALIZER;
125 static struct afb_evt_event *events = NULL;
126 static int event_id_counter = 0;
127 static int event_id_wrapped = 0;
130 * Broadcasts the 'event' of 'id' with its 'obj'
131 * 'obj' is released (like json_object_put)
132 * calls hooks if hookflags isn't 0
133 * Returns the count of listener having receive the event.
135 static int broadcast(const char *event, struct json_object *obj, int id, int hookflags)
138 struct afb_evt_listener *listener;
140 if (hookflags & afb_hook_flag_evt_broadcast_before)
141 afb_hook_evt_broadcast_before(event, id, obj);
143 pthread_mutex_lock(&listeners_mutex);
144 listener = listeners;
146 if (listener->itf->broadcast != NULL) {
147 listener->itf->broadcast(listener->closure, event, id, json_object_get(obj));
150 listener = listener->next;
152 pthread_mutex_unlock(&listeners_mutex);
153 if (hookflags & afb_hook_flag_evt_broadcast_after)
154 afb_hook_evt_broadcast_after(event, id, obj, result);
155 json_object_put(obj);
160 * Broadcasts the event 'evt' with its 'object'
161 * 'object' is released (like json_object_put)
162 * Returns the count of listener that received the event.
164 static int evt_broadcast(struct afb_evt_event *evt, struct json_object *object)
166 return broadcast(evt->name, object, evt->id, evt->hookflags);
170 * Broadcasts the 'event' with its 'object'
171 * 'object' is released (like json_object_put)
172 * Returns the count of listener having receive the event.
174 int afb_evt_broadcast(const char *event, struct json_object *object)
176 return broadcast(event, object, 0, -1);
180 * Pushes the event 'evt' with 'obj' to its listeners
181 * 'obj' is released (like json_object_put)
182 * Returns the count of listener taht received the event.
184 static int evt_push(struct afb_evt_event *evt, struct json_object *obj)
187 struct afb_evt_watch *watch;
188 struct afb_evt_listener *listener;
191 pthread_mutex_lock(&evt->mutex);
192 if (evt->hookflags & afb_hook_flag_evt_push_before)
193 afb_hook_evt_push_before(evt->name, evt->id, obj);
196 listener = watch->listener;
197 assert(listener->itf->push != NULL);
198 if (watch->activity != 0) {
199 listener->itf->push(listener->closure, evt->name, evt->id, json_object_get(obj));
202 watch = watch->next_by_event;
204 if (evt->hookflags & afb_hook_flag_evt_push_after)
205 afb_hook_evt_push_after(evt->name, evt->id, obj, result);
206 pthread_mutex_unlock(&evt->mutex);
207 json_object_put(obj);
212 * Returns the name associated to the event 'evt'.
214 static const char *evt_name(struct afb_evt_event *evt)
216 if (evt->hookflags & afb_hook_flag_evt_name)
217 afb_hook_evt_name(evt->name, evt->id);
224 static void remove_watch(struct afb_evt_watch *watch)
226 struct afb_evt_watch **prv;
227 struct afb_evt_event *evt;
228 struct afb_evt_listener *listener;
230 /* notify listener if needed */
232 listener = watch->listener;
233 if (watch->activity != 0 && listener->itf->remove != NULL)
234 listener->itf->remove(listener->closure, evt->name, evt->id);
236 /* unlink the watch for its event */
239 prv = &(*prv)->next_by_event;
240 *prv = watch->next_by_event;
242 /* unlink the watch for its listener */
243 prv = &listener->watchs;
245 prv = &(*prv)->next_by_listener;
246 *prv = watch->next_by_listener;
253 * Destroys the event 'evt'
255 static void evt_destroy(struct afb_evt_event *evt)
258 struct afb_evt_event **prv;
259 struct afb_evt_listener *listener;
262 /* unlinks the event if valid! */
263 pthread_mutex_lock(&events_mutex);
266 while (*prv && !(found = (*prv == evt)))
270 pthread_mutex_unlock(&events_mutex);
272 /* destroys the event */
274 /* removes all watchers */
275 while(evt->watchs != NULL) {
276 listener = evt->watchs->listener;
277 pthread_mutex_lock(&listener->mutex);
278 pthread_mutex_lock(&evt->mutex);
279 remove_watch(evt->watchs);
280 pthread_mutex_unlock(&evt->mutex);
281 pthread_mutex_unlock(&listener->mutex);
285 if (evt->hookflags & afb_hook_flag_evt_drop)
286 afb_hook_evt_drop(evt->name, evt->id);
289 pthread_mutex_destroy(&evt->mutex);
296 * Creates an event of 'name' and returns it.
297 * Returns an event with closure==NULL in case of error.
299 struct afb_event afb_evt_create_event(const char *name)
302 struct afb_evt_event *evt;
304 /* allocates the event */
306 evt = malloc(len + sizeof * evt);
310 /* initialize the event */
312 memcpy(evt->name, name, len + 1);
314 /* allocates the id */
315 pthread_mutex_lock(&events_mutex);
317 if (++event_id_counter < 0) {
318 event_id_wrapped = 1;
319 event_id_counter = 1024; /* heuristic: small numbers are not destroyed */
321 if (!event_id_wrapped)
324 while(evt != NULL && evt->id != event_id_counter)
326 } while (evt != NULL);
328 /* initialize the event */
329 memcpy(evt->name, name, len + 1);
332 evt->id = event_id_counter;
333 pthread_mutex_init(&evt->mutex, NULL);
335 evt->hookflags = afb_hook_flags_evt(evt->name);
336 if (evt->hookflags & afb_hook_flag_evt_create)
337 afb_hook_evt_create(evt->name, evt->id);
338 pthread_mutex_unlock(&events_mutex);
340 /* returns the event */
341 return (struct afb_event){ .itf = &afb_evt_event_itf, .closure = evt };
343 return (struct afb_event){ .itf = NULL, .closure = NULL };
347 * Returns the name of the 'event'
349 const char *afb_evt_event_name(struct afb_event event)
351 return (event.itf != &afb_evt_event_itf) ? NULL : ((struct afb_evt_event *)event.closure)->name;
355 * Returns the id of the 'event'
357 int afb_evt_event_id(struct afb_event event)
359 return (event.itf != &afb_evt_event_itf) ? 0 : ((struct afb_evt_event *)event.closure)->id;
363 * Returns an instance of the listener defined by the 'send' callback
365 * Returns NULL in case of memory depletion.
367 struct afb_evt_listener *afb_evt_listener_create(const struct afb_evt_itf *itf, void *closure)
369 struct afb_evt_listener *listener;
371 /* search if an instance already exists */
372 pthread_mutex_lock(&listeners_mutex);
373 listener = listeners;
374 while (listener != NULL) {
375 if (listener->itf == itf && listener->closure == closure) {
376 listener = afb_evt_listener_addref(listener);
379 listener = listener->next;
383 listener = calloc(1, sizeof *listener);
384 if (listener != NULL) {
387 listener->closure = closure;
388 listener->watchs = NULL;
389 listener->refcount = 1;
390 pthread_mutex_init(&listener->mutex, NULL);
391 listener->next = listeners;
392 listeners = listener;
395 pthread_mutex_unlock(&listeners_mutex);
400 * Increases the reference count of 'listener' and returns it
402 struct afb_evt_listener *afb_evt_listener_addref(struct afb_evt_listener *listener)
404 __atomic_add_fetch(&listener->refcount, 1, __ATOMIC_RELAXED);
409 * Decreases the reference count of the 'listener' and destroys it
412 void afb_evt_listener_unref(struct afb_evt_listener *listener)
414 struct afb_evt_listener **prv;
415 struct afb_evt_event *evt;
417 if (!__atomic_sub_fetch(&listener->refcount, 1, __ATOMIC_RELAXED)) {
419 /* unlink the listener */
420 pthread_mutex_lock(&listeners_mutex);
422 while (*prv != listener)
424 *prv = listener->next;
425 pthread_mutex_unlock(&listeners_mutex);
427 /* remove the watchers */
428 pthread_mutex_lock(&listener->mutex);
429 while (listener->watchs != NULL) {
430 evt = listener->watchs->event;
431 pthread_mutex_lock(&evt->mutex);
432 remove_watch(listener->watchs);
433 pthread_mutex_unlock(&evt->mutex);
435 pthread_mutex_unlock(&listener->mutex);
437 /* free the listener */
438 pthread_mutex_destroy(&listener->mutex);
444 * Makes the 'listener' watching 'event'
445 * Returns 0 in case of success or else -1.
447 int afb_evt_add_watch(struct afb_evt_listener *listener, struct afb_event event)
449 struct afb_evt_watch *watch;
450 struct afb_evt_event *evt;
452 /* check parameter */
453 if (event.itf != &afb_evt_event_itf || listener->itf->push == NULL) {
458 /* search the existing watch for the listener */
460 pthread_mutex_lock(&listener->mutex);
461 watch = listener->watchs;
462 while(watch != NULL) {
463 if (watch->event == evt)
465 watch = watch->next_by_listener;
468 /* not found, allocate a new */
469 watch = malloc(sizeof *watch);
471 pthread_mutex_unlock(&listener->mutex);
476 /* initialise and link */
479 watch->listener = listener;
480 watch->next_by_listener = listener->watchs;
481 listener->watchs = watch;
482 pthread_mutex_lock(&evt->mutex);
483 watch->next_by_event = evt->watchs;
485 pthread_mutex_unlock(&evt->mutex);
488 if (watch->activity == 0 && listener->itf->add != NULL)
489 listener->itf->add(listener->closure, evt->name, evt->id);
491 pthread_mutex_unlock(&listener->mutex);
497 * Avoids the 'listener' to watch 'event'
498 * Returns 0 in case of success or else -1.
500 int afb_evt_remove_watch(struct afb_evt_listener *listener, struct afb_event event)
502 struct afb_evt_watch *watch;
503 struct afb_evt_event *evt;
505 /* check parameter */
506 if (event.itf != &afb_evt_event_itf) {
511 /* search the existing watch */
513 pthread_mutex_lock(&listener->mutex);
514 watch = listener->watchs;
515 while(watch != NULL) {
516 if (watch->event == evt) {
517 if (watch->activity != 0) {
519 if (watch->activity == 0 && listener->itf->remove != NULL)
520 listener->itf->remove(listener->closure, evt->name, evt->id);
522 pthread_mutex_unlock(&listener->mutex);
525 watch = watch->next_by_listener;
527 pthread_mutex_unlock(&listener->mutex);
533 * update the hooks for events
535 void afb_evt_update_hooks()
537 struct afb_evt_event *evt;
539 pthread_mutex_lock(&events_mutex);
540 for (evt = events ; evt ; evt = evt->next)
541 evt->hookflags = afb_hook_flags_evt(evt->name);
542 pthread_mutex_unlock(&events_mutex);