2 * Copyright (c) 2016, JANET(UK)
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of JANET(UK) nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
24 * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
25 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
29 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
30 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
31 * OF THE POSSIBILITY OF SUCH DAMAGE.
44 static int tr_mq_msg_destructor(void *object)
46 TR_MQ_MSG *msg=talloc_get_type_abort(object, TR_MQ_MSG);
47 if ( (msg->p!=NULL) && (msg->p_free!=NULL))
52 TR_MQ_MSG *tr_mq_msg_new(TALLOC_CTX *mem_ctx, const char *message, TR_MQ_PRIORITY prio)
54 TR_MQ_MSG *msg=talloc(mem_ctx, TR_MQ_MSG);
58 msg->message=talloc_strdup(msg, message);
59 if (msg->message==NULL) {
64 talloc_set_destructor((void *)msg, tr_mq_msg_destructor);
69 void tr_mq_msg_free(TR_MQ_MSG *msg)
75 TR_MQ_PRIORITY tr_mq_msg_get_prio(TR_MQ_MSG *msg)
80 const char *tr_mq_msg_get_message(TR_MQ_MSG *msg)
85 void *tr_mq_msg_get_payload(TR_MQ_MSG *msg)
90 /* call with a pointer to the payload and a function to free it later */
91 void tr_mq_msg_set_payload(TR_MQ_MSG *msg, void *p, void (*p_free)(void *))
98 static TR_MQ_MSG *tr_mq_msg_get_next(TR_MQ_MSG *msg)
103 static void tr_mq_msg_set_next(TR_MQ_MSG *msg, TR_MQ_MSG *next)
109 TR_MQ *tr_mq_new(TALLOC_CTX *mem_ctx)
111 TR_MQ *mq=talloc(mem_ctx, TR_MQ);
112 pthread_condattr_t cattr;
115 pthread_mutex_init(&(mq->mutex), 0);
116 pthread_condattr_init(&cattr);
118 pthread_condattr_setclock(&cattr, CLOCK_MONOTONIC); /* use the monotonic clock for timeouts */
119 pthread_cond_init(&(mq->have_msg_cond), &cattr);
120 pthread_condattr_destroy(&cattr);
124 mq->last_hi_prio=NULL;
127 mq->notify_cb_arg=NULL;
132 void tr_mq_free(TR_MQ *mq)
135 tr_mq_lock(mq); /* don't pull the rug out from under someone */
140 int tr_mq_lock(TR_MQ *mq)
142 return pthread_mutex_lock(&(mq->mutex));
145 int tr_mq_unlock(TR_MQ *mq)
147 return pthread_mutex_unlock(&(mq->mutex));
150 static TR_MQ_MSG *tr_mq_get_head(TR_MQ *mq)
155 static void tr_mq_set_head(TR_MQ *mq, TR_MQ_MSG *msg)
160 static TR_MQ_MSG *tr_mq_get_tail(TR_MQ *mq)
165 static void tr_mq_set_tail(TR_MQ *mq, TR_MQ_MSG *msg)
170 void tr_mq_set_notify_cb(TR_MQ *mq, TR_MQ_NOTIFY_FN cb, void *arg)
173 mq->notify_cb_arg=arg;
176 void tr_mq_clear(TR_MQ *mq)
182 m=tr_mq_get_head(mq);
184 n=tr_mq_msg_get_next(m);
188 tr_mq_set_head(mq, NULL);
189 tr_mq_set_tail(mq, NULL);
193 static int tr_mq_empty(TR_MQ *mq)
195 return tr_mq_get_head(mq)==NULL;
198 /* puts msg in mq's talloc context */
199 static void tr_mq_append(TR_MQ *mq, TR_MQ_MSG *msg)
201 if (tr_mq_get_head(mq)==NULL) {
202 tr_mq_set_head(mq, msg);
203 tr_mq_set_tail(mq, msg);
205 tr_mq_msg_set_next(tr_mq_get_tail(mq), msg); /* add to list */
206 tr_mq_set_tail(mq, msg); /* update tail of list */
208 talloc_steal(mq, msg);
211 static void tr_mq_append_high_prio(TR_MQ *mq, TR_MQ_MSG *new)
213 if (tr_mq_get_head(mq)==NULL) {
214 tr_mq_set_head(mq, new);
215 tr_mq_set_tail(mq, new);
216 } else if (mq->last_hi_prio==NULL) {
217 tr_mq_msg_set_next(new, tr_mq_get_head(mq)); /* add to front of list */
218 tr_mq_set_head(mq, new); /* update head of list */
220 tr_mq_msg_set_next(new, tr_mq_msg_get_next(mq->last_hi_prio));
221 tr_mq_msg_set_next(mq->last_hi_prio, new); /* add to end of hi prio msgs */
223 mq->last_hi_prio=new; /* in any case, this is now the last high priority msg */
224 talloc_steal(mq,new);
227 #define DEBUG_TR_MQ 0
229 static void tr_mq_print(TR_MQ *mq)
231 TR_MQ_MSG *m=mq->head;
234 tr_debug("tr_mq_print: mq contents:");
237 tr_debug("tr_mq_print: Entry %02d: %-15s (prio %d)",
238 ii, tr_mq_msg_get_message(m), tr_mq_msg_get_prio(m));
239 m=tr_mq_msg_get_next(m);
243 void tr_mq_add(TR_MQ *mq, TR_MQ_MSG *msg)
246 TR_MQ_NOTIFY_FN notify_cb=NULL;
247 void *notify_cb_arg=NULL;
251 was_empty=tr_mq_empty(mq);
252 switch (tr_mq_msg_get_prio(msg)) {
253 case TR_MQ_PRIO_HIGH:
254 tr_mq_append_high_prio(mq, msg);
257 tr_mq_append(mq, msg);
260 /* before releasing the mutex, get notify_cb data out of mq */
261 notify_cb=mq->notify_cb;
262 notify_cb_arg=mq->notify_cb_arg;
268 /* Before releasing the lock, signal any waiting threads that there's now
269 * something in the queue. Used for blocking tr_mq_pop() call. */
272 pthread_cond_broadcast(&(mq->have_msg_cond));
276 /* see if we need to tell someone we became non-empty */
277 if (was_empty && (notify_cb!=NULL))
278 notify_cb(mq, notify_cb_arg);
281 /* Compute an absolute time from a desired timeout interval for use with tr_mq_pop().
282 * Fills in *ts and returns 0 on success. */
283 int tr_mq_pop_timeout(time_t seconds, struct timespec *ts)
285 if (0!=clock_gettime(CLOCK_MONOTONIC, ts))
292 /* Retrieves a message from the queue, waiting until absolute
293 * time ts_abort before giving up (using CLOCK_MONOTONIC). If ts_abort
294 * has passed, returns an existing message but will not wait if one is
295 * not already available. If ts_abort is null, no blocking. Not
296 * guaranteed to wait if an error occurs - immediately returns without
297 * a message. Use tr_mq_pop_timeout() to get an absolute time that
298 * is guaranteed compatible with this function.
300 * Caller should free msg via tr_mq_msg_free when done with it. It stays
301 * in the TR_MQ's context, though, so use talloc_steal() if you want to do
302 * something clever with it. */
303 TR_MQ_MSG *tr_mq_pop(TR_MQ *mq, struct timespec *ts_abort)
305 TR_MQ_MSG *popped=NULL;
309 if ((tr_mq_get_head(mq)==NULL) && (ts_abort!=NULL)) {
310 /* No msgs yet, and blocking was requested */
311 while ((wait_err==0) && (NULL==tr_mq_get_head(mq)))
312 wait_err=pthread_cond_timedwait(&(mq->have_msg_cond),
316 if ((wait_err!=0) && (wait_err!=ETIMEDOUT)) {
317 tr_notice("tr_mq_pop: error waiting for message.");
320 /* if it timed out, ok to go ahead and check once more for a message, so no special exit */
323 if (tr_mq_get_head(mq)!=NULL) {
324 popped=tr_mq_get_head(mq);
325 tr_mq_set_head(mq, tr_mq_msg_get_next(popped)); /* popped is the old head */
327 if (popped==mq->last_hi_prio)
328 mq->last_hi_prio=NULL;
330 if (tr_mq_get_head(mq)==NULL)
331 tr_mq_set_tail(mq, NULL); /* just popped the last element */
335 tr_mq_msg_set_next(popped, NULL); /* disconnect from list */