Split waitqueue from utils
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463d1c6435
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#ifndef _LIGHTTPD_WAITQUEUE_H_
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#define _LIGHTTPD_WAITQUEUE_H_
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#ifndef _LIGHTTPD_BASE_H_
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#error Please include <lighttpd/base.h> instead of this file
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#endif
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struct waitqueue_elem {
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gboolean queued;
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ev_tstamp ts;
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waitqueue_elem *prev;
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waitqueue_elem *next;
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gpointer data;
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};
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struct waitqueue {
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waitqueue_elem *head;
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waitqueue_elem *tail;
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ev_timer timer;
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struct ev_loop *loop;
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gdouble delay;
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};
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/*
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* waitqueues are queues used to implement delays for certain tasks in a lightweight, non-blocking way
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* they are used for io timeouts or throttling for example
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* waitqueue_push, waitqueue_pop and waitqueue_remove have O(1) complexity
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*/
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/* initializes a waitqueue by creating and starting the ev_timer. precision is sub-seconds */
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LI_API void waitqueue_init(waitqueue *queue, struct ev_loop *loop, waitqueue_cb callback, gdouble delay, gpointer data);
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/* stops the waitqueue. to restart it, simply call waitqueue_update */
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LI_API void waitqueue_stop(waitqueue *queue);
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/* updates the timeout of the waitqueue, you should allways call this at the end of your callback */
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LI_API void waitqueue_update(waitqueue *queue);
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/* moves the element to the end of the queue if already queued, appends it to the end otherwise */
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LI_API void waitqueue_push(waitqueue *queue, waitqueue_elem *elem);
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/* pops the first ready! element from the queue or NULL if none ready yet. this should be called in your callback */
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LI_API waitqueue_elem *waitqueue_pop(waitqueue *queue);
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/* removes an element from the queue */
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LI_API void waitqueue_remove(waitqueue *queue, waitqueue_elem *elem);
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#endif
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@ -0,0 +1,103 @@
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#include <lighttpd/base.h>
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void waitqueue_init(waitqueue *queue, struct ev_loop *loop, waitqueue_cb callback, gdouble delay, gpointer data) {
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ev_timer_init(&queue->timer, callback, delay, delay);
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ev_timer_start(loop, &queue->timer);
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queue->timer.data = data;
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queue->head = queue->tail = NULL;
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queue->loop = loop;
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queue->delay = delay;
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}
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void waitqueue_stop(waitqueue *queue) {
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ev_timer_stop(queue->loop, &queue->timer);
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}
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void waitqueue_update(waitqueue *queue) {
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ev_tstamp repeat;
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if (queue->head) {
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repeat = queue->head->ts + queue->delay - ev_now(queue->loop);
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} else
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repeat = queue->delay;
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if (queue->timer.repeat != repeat)
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{
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queue->timer.repeat = repeat;
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ev_timer_again(queue->loop, &queue->timer);
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}
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}
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void waitqueue_push(waitqueue *queue, waitqueue_elem *elem) {
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elem->ts = ev_now(queue->loop);
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if (!elem->queued) {
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elem->queued = TRUE;
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/* not in the queue yet, insert at the end */
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if (!queue->head) {
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/* queue is empty */
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queue->head = elem;
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queue->tail = elem;
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elem->prev = NULL;
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elem->next = NULL;
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} else {
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/* queue not empty */
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elem->prev = queue->tail;
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elem->next = NULL;
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queue->tail->next = elem;
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queue->tail = elem;
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}
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} else {
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/* already queued, move to end */
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if (elem == queue->tail)
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return;
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if (elem == queue->head) {
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queue->head = elem->next;
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if (elem->next)
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elem->next->prev = NULL;
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}
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elem->prev = queue->tail;
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elem->next = NULL;
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queue->tail->next = elem;
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queue->tail = elem;
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}
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}
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waitqueue_elem *waitqueue_pop(waitqueue *queue) {
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waitqueue_elem *elem = queue->head;
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ev_tstamp now = ev_now(queue->loop);
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if (!elem || (elem->ts + queue->delay) >= now) {
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return NULL;
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}
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if (elem != queue->tail)
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elem->next->prev = NULL;
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queue->head = elem->next;
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elem->queued = FALSE;
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return elem;
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}
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void waitqueue_remove(waitqueue *queue, waitqueue_elem *elem) {
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if (!elem->queued)
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return;
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if (elem == queue->head)
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queue->head = elem->next;
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else
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elem->prev->next = elem->next;
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if (elem == queue->tail)
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queue->tail = elem->prev;
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else
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elem->next->prev = elem->prev;
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elem->queued = FALSE;
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}
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