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/******************************************************************************
*
* Copyright (C) 2014 Google, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
******************************************************************************/
#include <assert.h>
#include <pthread.h>
#include <stdlib.h>
#include "osi/include/allocator.h"
#include "osi/include/fixed_queue.h"
#include "osi/include/list.h"
#include "osi/include/osi.h"
#include "osi/include/semaphore.h"
#include "osi/include/reactor.h"
typedef struct fixed_queue_t {
list_t *list;
semaphore_t *enqueue_sem;
semaphore_t *dequeue_sem;
pthread_mutex_t lock;
size_t capacity;
reactor_object_t *dequeue_object;
fixed_queue_cb dequeue_ready;
void *dequeue_context;
} fixed_queue_t;
static void internal_dequeue_ready(void *context);
fixed_queue_t *fixed_queue_new(size_t capacity) {
fixed_queue_t *ret = osi_calloc(sizeof(fixed_queue_t));
if (!ret)
goto error;
pthread_mutex_init(&ret->lock, NULL);
ret->capacity = capacity;
ret->list = list_new(NULL);
if (!ret->list)
goto error;
ret->enqueue_sem = semaphore_new(capacity);
if (!ret->enqueue_sem)
goto error;
ret->dequeue_sem = semaphore_new(0);
if (!ret->dequeue_sem)
goto error;
return ret;
error:;
fixed_queue_free(ret, NULL);
return NULL;
}
void fixed_queue_free(fixed_queue_t *queue, fixed_queue_free_cb free_cb) {
if (!queue)
return;
fixed_queue_unregister_dequeue(queue);
if (free_cb)
for (const list_node_t *node = list_begin(queue->list); node != list_end(queue->list); node = list_next(node))
free_cb(list_node(node));
list_free(queue->list);
semaphore_free(queue->enqueue_sem);
semaphore_free(queue->dequeue_sem);
pthread_mutex_destroy(&queue->lock);
osi_free(queue);
}
bool fixed_queue_is_empty(fixed_queue_t *queue) {
assert(queue != NULL);
pthread_mutex_lock(&queue->lock);
bool is_empty = list_is_empty(queue->list);
pthread_mutex_unlock(&queue->lock);
return is_empty;
}
size_t fixed_queue_capacity(fixed_queue_t *queue) {
assert(queue != NULL);
return queue->capacity;
}
void fixed_queue_enqueue(fixed_queue_t *queue, void *data) {
assert(queue != NULL);
assert(data != NULL);
semaphore_wait(queue->enqueue_sem);
pthread_mutex_lock(&queue->lock);
list_append(queue->list, data);
pthread_mutex_unlock(&queue->lock);
semaphore_post(queue->dequeue_sem);
}
void *fixed_queue_dequeue(fixed_queue_t *queue) {
assert(queue != NULL);
semaphore_wait(queue->dequeue_sem);
pthread_mutex_lock(&queue->lock);
void *ret = list_front(queue->list);
list_remove(queue->list, ret);
pthread_mutex_unlock(&queue->lock);
semaphore_post(queue->enqueue_sem);
return ret;
}
bool fixed_queue_try_enqueue(fixed_queue_t *queue, void *data) {
assert(queue != NULL);
assert(data != NULL);
if (!semaphore_try_wait(queue->enqueue_sem))
return false;
pthread_mutex_lock(&queue->lock);
list_append(queue->list, data);
pthread_mutex_unlock(&queue->lock);
semaphore_post(queue->dequeue_sem);
return true;
}
void *fixed_queue_try_dequeue(fixed_queue_t *queue) {
assert(queue != NULL);
if (!semaphore_try_wait(queue->dequeue_sem))
return NULL;
pthread_mutex_lock(&queue->lock);
void *ret = list_front(queue->list);
list_remove(queue->list, ret);
pthread_mutex_unlock(&queue->lock);
semaphore_post(queue->enqueue_sem);
return ret;
}
void *fixed_queue_try_peek(fixed_queue_t *queue) {
assert(queue != NULL);
pthread_mutex_lock(&queue->lock);
// Because protected by the lock, the empty and front calls are atomic and not a race condition
void *ret = list_is_empty(queue->list) ? NULL : list_front(queue->list);
pthread_mutex_unlock(&queue->lock);
return ret;
}
int fixed_queue_get_dequeue_fd(const fixed_queue_t *queue) {
assert(queue != NULL);
return semaphore_get_fd(queue->dequeue_sem);
}
int fixed_queue_get_enqueue_fd(const fixed_queue_t *queue) {
assert(queue != NULL);
return semaphore_get_fd(queue->enqueue_sem);
}
void fixed_queue_register_dequeue(fixed_queue_t *queue, reactor_t *reactor, fixed_queue_cb ready_cb, void *context) {
assert(queue != NULL);
assert(reactor != NULL);
assert(ready_cb != NULL);
// Make sure we're not already registered
fixed_queue_unregister_dequeue(queue);
queue->dequeue_ready = ready_cb;
queue->dequeue_context = context;
queue->dequeue_object = reactor_register(
reactor,
fixed_queue_get_dequeue_fd(queue),
queue,
internal_dequeue_ready,
NULL
);
}
void fixed_queue_unregister_dequeue(fixed_queue_t *queue) {
assert(queue != NULL);
if (queue->dequeue_object) {
reactor_unregister(queue->dequeue_object);
queue->dequeue_object = NULL;
}
}
static void internal_dequeue_ready(void *context) {
assert(context != NULL);
fixed_queue_t *queue = context;
queue->dequeue_ready(queue, queue->dequeue_context);
}
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