1 /* Copyright 2000-2005 The Apache Software Foundation or its licensors, as
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
30 #include "apr_portable.h"
31 #include "apr_thread_mutex.h"
32 #include "apr_thread_cond.h"
33 #include "apr_errno.h"
34 #include "apr_queue.h"
38 * define this to get debug messages
45 unsigned int nelts; /**< # elements */
46 unsigned int in; /**< next empty location */
47 unsigned int out; /**< next filled location */
48 unsigned int bounds;/**< max size of queue */
49 unsigned int full_waiters;
50 unsigned int empty_waiters;
51 apr_thread_mutex_t *one_big_mutex;
52 apr_thread_cond_t *not_empty;
53 apr_thread_cond_t *not_full;
58 static void Q_DBG(char*msg, apr_queue_t *q) {
59 fprintf(stderr, "%ld\t#%d in %d out %d\t%s\n",
60 apr_os_thread_current(),
61 q->nelts, q->in, q->out,
70 * Detects when the apr_queue_t is full. This utility function is expected
71 * to be called from within critical sections, and is not threadsafe.
73 #define apr_queue_full(queue) ((queue)->nelts == (queue)->bounds)
76 * Detects when the apr_queue_t is empty. This utility function is expected
77 * to be called from within critical sections, and is not threadsafe.
79 #define apr_queue_empty(queue) ((queue)->nelts == 0)
82 * Callback routine that is called to destroy this
83 * apr_queue_t when its pool is destroyed.
85 static apr_status_t queue_destroy(void *data)
87 apr_queue_t *queue = data;
89 /* Ignore errors here, we can't do anything about them anyway. */
91 apr_thread_cond_destroy(queue->not_empty);
92 apr_thread_cond_destroy(queue->not_full);
93 apr_thread_mutex_destroy(queue->one_big_mutex);
99 * Initialize the apr_queue_t.
101 APU_DECLARE(apr_status_t) apr_queue_create(apr_queue_t **q,
102 unsigned int queue_capacity,
107 queue = apr_palloc(a, sizeof(apr_queue_t));
110 /* nested doesn't work ;( */
111 rv = apr_thread_mutex_create(&queue->one_big_mutex,
112 APR_THREAD_MUTEX_UNNESTED,
114 if (rv != APR_SUCCESS) {
118 rv = apr_thread_cond_create(&queue->not_empty, a);
119 if (rv != APR_SUCCESS) {
123 rv = apr_thread_cond_create(&queue->not_full, a);
124 if (rv != APR_SUCCESS) {
128 /* Set all the data in the queue to NULL */
129 queue->data = apr_pcalloc(a, queue_capacity * sizeof(void*));
130 queue->bounds = queue_capacity;
134 queue->terminated = 0;
135 queue->full_waiters = 0;
136 queue->empty_waiters = 0;
138 apr_pool_cleanup_register(a, queue, queue_destroy, apr_pool_cleanup_null);
144 * Push new data onto the queue. Blocks if the queue is full. Once
145 * the push operation has completed, it signals other threads waiting
146 * in apr_queue_pop() that they may continue consuming sockets.
148 APU_DECLARE(apr_status_t) apr_queue_push(apr_queue_t *queue, void *data)
152 if (queue->terminated) {
153 return APR_EOF; /* no more elements ever again */
156 rv = apr_thread_mutex_lock(queue->one_big_mutex);
157 if (rv != APR_SUCCESS) {
161 if (apr_queue_full(queue)) {
162 if (!queue->terminated) {
163 queue->full_waiters++;
164 rv = apr_thread_cond_wait(queue->not_full, queue->one_big_mutex);
165 queue->full_waiters--;
166 if (rv != APR_SUCCESS) {
167 apr_thread_mutex_unlock(queue->one_big_mutex);
171 /* If we wake up and it's still empty, then we were interrupted */
172 if (apr_queue_full(queue)) {
173 Q_DBG("queue full (intr)", queue);
174 rv = apr_thread_mutex_unlock(queue->one_big_mutex);
175 if (rv != APR_SUCCESS) {
178 if (queue->terminated) {
179 return APR_EOF; /* no more elements ever again */
187 queue->data[queue->in] = data;
188 queue->in = (queue->in + 1) % queue->bounds;
191 if (queue->empty_waiters) {
192 Q_DBG("sig !empty", queue);
193 rv = apr_thread_cond_signal(queue->not_empty);
194 if (rv != APR_SUCCESS) {
195 apr_thread_mutex_unlock(queue->one_big_mutex);
200 rv = apr_thread_mutex_unlock(queue->one_big_mutex);
205 * Push new data onto the queue. Blocks if the queue is full. Once
206 * the push operation has completed, it signals other threads waiting
207 * in apr_queue_pop() that they may continue consuming sockets.
209 APU_DECLARE(apr_status_t) apr_queue_trypush(apr_queue_t *queue, void *data)
213 if (queue->terminated) {
214 return APR_EOF; /* no more elements ever again */
217 rv = apr_thread_mutex_lock(queue->one_big_mutex);
218 if (rv != APR_SUCCESS) {
222 if (apr_queue_full(queue)) {
223 rv = apr_thread_mutex_unlock(queue->one_big_mutex);
227 queue->data[queue->in] = data;
228 queue->in = (queue->in + 1) % queue->bounds;
231 if (queue->empty_waiters) {
232 Q_DBG("sig !empty", queue);
233 rv = apr_thread_cond_signal(queue->not_empty);
234 if (rv != APR_SUCCESS) {
235 apr_thread_mutex_unlock(queue->one_big_mutex);
240 rv = apr_thread_mutex_unlock(queue->one_big_mutex);
247 APU_DECLARE(unsigned int) apr_queue_size(apr_queue_t *queue) {
252 * Retrieves the next item from the queue. If there are no
253 * items available, it will block until one becomes available.
254 * Once retrieved, the item is placed into the address specified by
257 APU_DECLARE(apr_status_t) apr_queue_pop(apr_queue_t *queue, void **data)
261 if (queue->terminated) {
262 return APR_EOF; /* no more elements ever again */
265 rv = apr_thread_mutex_lock(queue->one_big_mutex);
266 if (rv != APR_SUCCESS) {
270 /* Keep waiting until we wake up and find that the queue is not empty. */
271 if (apr_queue_empty(queue)) {
272 if (!queue->terminated) {
273 queue->empty_waiters++;
274 rv = apr_thread_cond_wait(queue->not_empty, queue->one_big_mutex);
275 queue->empty_waiters--;
276 if (rv != APR_SUCCESS) {
277 apr_thread_mutex_unlock(queue->one_big_mutex);
281 /* If we wake up and it's still empty, then we were interrupted */
282 if (apr_queue_empty(queue)) {
283 Q_DBG("queue empty (intr)", queue);
284 rv = apr_thread_mutex_unlock(queue->one_big_mutex);
285 if (rv != APR_SUCCESS) {
288 if (queue->terminated) {
289 return APR_EOF; /* no more elements ever again */
297 *data = queue->data[queue->out];
300 queue->out = (queue->out + 1) % queue->bounds;
301 if (queue->full_waiters) {
302 Q_DBG("signal !full", queue);
303 rv = apr_thread_cond_signal(queue->not_full);
304 if (rv != APR_SUCCESS) {
305 apr_thread_mutex_unlock(queue->one_big_mutex);
310 rv = apr_thread_mutex_unlock(queue->one_big_mutex);
315 * Retrieves the next item from the queue. If there are no
316 * items available, it will block until one becomes available.
317 * Once retrieved, the item is placed into the address specified by
320 APU_DECLARE(apr_status_t) apr_queue_trypop(apr_queue_t *queue, void **data)
324 if (queue->terminated) {
325 return APR_EOF; /* no more elements ever again */
328 rv = apr_thread_mutex_lock(queue->one_big_mutex);
329 if (rv != APR_SUCCESS) {
333 /* Keep waiting until we wake up and find that the queue is not empty. */
334 if (apr_queue_empty(queue)) {
335 rv = apr_thread_mutex_unlock(queue->one_big_mutex);
339 *data = queue->data[queue->out];
342 queue->out = (queue->out + 1) % queue->bounds;
343 if (queue->full_waiters) {
344 Q_DBG("signal !full", queue);
345 rv = apr_thread_cond_signal(queue->not_full);
346 if (rv != APR_SUCCESS) {
347 apr_thread_mutex_unlock(queue->one_big_mutex);
352 rv = apr_thread_mutex_unlock(queue->one_big_mutex);
356 APU_DECLARE(apr_status_t) apr_queue_interrupt_all(apr_queue_t *queue)
359 Q_DBG("intr all", queue);
360 if ((rv = apr_thread_mutex_lock(queue->one_big_mutex)) != APR_SUCCESS) {
363 apr_thread_cond_broadcast(queue->not_empty);
364 apr_thread_cond_broadcast(queue->not_full);
366 if ((rv = apr_thread_mutex_unlock(queue->one_big_mutex)) != APR_SUCCESS) {
373 APU_DECLARE(apr_status_t) apr_queue_term(apr_queue_t *queue)
377 if ((rv = apr_thread_mutex_lock(queue->one_big_mutex)) != APR_SUCCESS) {
381 /* we must hold one_big_mutex when setting this... otherwise,
382 * we could end up setting it and waking everybody up just after a
383 * would-be popper checks it but right before they block
385 queue->terminated = 1;
386 if ((rv = apr_thread_mutex_unlock(queue->one_big_mutex)) != APR_SUCCESS) {
389 return apr_queue_interrupt_all(queue);
392 #endif /* APR_HAS_THREADS */