in place of a very common construct. I also used it in a number of places in chan_sip. if (id > -1) ast_sched_del(sched, id); id = ast_sched_add(sched, ...); changes to: ast_sched_replace(id, sched, ...); git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@79861 65c4cc65-6c06-0410-ace0-fbb531ad65f3
412 lines
10 KiB
C
412 lines
10 KiB
C
/*
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* Asterisk -- An open source telephony toolkit.
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*
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* Copyright (C) 1999 - 2005, Digium, Inc.
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*
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* Mark Spencer <markster@digium.com>
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*
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* See http://www.asterisk.org for more information about
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* the Asterisk project. Please do not directly contact
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* any of the maintainers of this project for assistance;
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* the project provides a web site, mailing lists and IRC
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* channels for your use.
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*
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* This program is free software, distributed under the terms of
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* the GNU General Public License Version 2. See the LICENSE file
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* at the top of the source tree.
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*/
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/*! \file
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*
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* \brief Scheduler Routines (from cheops-NG)
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*
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* \author Mark Spencer <markster@digium.com>
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*/
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#include "asterisk.h"
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ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
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#ifdef DEBUG_SCHEDULER
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#define DEBUG(a) do { \
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if (option_debug) \
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DEBUG_M(a) \
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} while (0)
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#else
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#define DEBUG(a)
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#endif
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#include <stdio.h>
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#include <stdlib.h>
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#include <sys/time.h>
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#include <unistd.h>
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#include <string.h>
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#include "asterisk/sched.h"
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#include "asterisk/logger.h"
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#include "asterisk/channel.h"
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#include "asterisk/lock.h"
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#include "asterisk/utils.h"
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#include "asterisk/linkedlists.h"
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#include "asterisk/options.h"
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struct sched {
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AST_LIST_ENTRY(sched) list;
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int id; /*!< ID number of event */
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struct timeval when; /*!< Absolute time event should take place */
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int resched; /*!< When to reschedule */
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int variable; /*!< Use return value from callback to reschedule */
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void *data; /*!< Data */
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ast_sched_cb callback; /*!< Callback */
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};
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struct sched_context {
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ast_mutex_t lock;
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unsigned int eventcnt; /*!< Number of events processed */
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unsigned int schedcnt; /*!< Number of outstanding schedule events */
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AST_LIST_HEAD_NOLOCK(, sched) schedq; /*!< Schedule entry and main queue */
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#ifdef SCHED_MAX_CACHE
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AST_LIST_HEAD_NOLOCK(, sched) schedc; /*!< Cache of unused schedule structures and how many */
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unsigned int schedccnt;
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#endif
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};
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struct sched_context *sched_context_create(void)
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{
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struct sched_context *tmp;
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if (!(tmp = ast_calloc(1, sizeof(*tmp))))
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return NULL;
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ast_mutex_init(&tmp->lock);
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tmp->eventcnt = 1;
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return tmp;
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}
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void sched_context_destroy(struct sched_context *con)
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{
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struct sched *s;
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ast_mutex_lock(&con->lock);
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#ifdef SCHED_MAX_CACHE
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/* Eliminate the cache */
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while ((s = AST_LIST_REMOVE_HEAD(&con->schedc, list)))
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ast_free(s);
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#endif
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/* And the queue */
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while ((s = AST_LIST_REMOVE_HEAD(&con->schedq, list)))
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ast_free(s);
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/* And the context */
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ast_mutex_unlock(&con->lock);
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ast_mutex_destroy(&con->lock);
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ast_free(con);
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}
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static struct sched *sched_alloc(struct sched_context *con)
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{
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struct sched *tmp;
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/*
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* We keep a small cache of schedule entries
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* to minimize the number of necessary malloc()'s
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*/
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#ifdef SCHED_MAX_CACHE
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if ((tmp = AST_LIST_REMOVE_HEAD(&con->schedc, list)))
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con->schedccnt--;
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else
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#endif
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tmp = ast_calloc(1, sizeof(*tmp));
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return tmp;
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}
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static void sched_release(struct sched_context *con, struct sched *tmp)
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{
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/*
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* Add to the cache, or just free() if we
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* already have too many cache entries
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*/
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#ifdef SCHED_MAX_CACHE
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if (con->schedccnt < SCHED_MAX_CACHE) {
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AST_LIST_INSERT_HEAD(&con->schedc, tmp, list);
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con->schedccnt++;
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} else
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#endif
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ast_free(tmp);
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}
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/*! \brief
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* Return the number of milliseconds
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* until the next scheduled event
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*/
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int ast_sched_wait(struct sched_context *con)
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{
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int ms;
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DEBUG(ast_debug(1, "ast_sched_wait()\n"));
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ast_mutex_lock(&con->lock);
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if (AST_LIST_EMPTY(&con->schedq)) {
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ms = -1;
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} else {
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ms = ast_tvdiff_ms(AST_LIST_FIRST(&con->schedq)->when, ast_tvnow());
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if (ms < 0)
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ms = 0;
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}
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ast_mutex_unlock(&con->lock);
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return ms;
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}
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/*! \brief
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* Take a sched structure and put it in the
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* queue, such that the soonest event is
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* first in the list.
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*/
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static void schedule(struct sched_context *con, struct sched *s)
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{
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struct sched *cur = NULL;
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AST_LIST_TRAVERSE_SAFE_BEGIN(&con->schedq, cur, list) {
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if (ast_tvcmp(s->when, cur->when) == -1) {
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AST_LIST_INSERT_BEFORE_CURRENT(&con->schedq, s, list);
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break;
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}
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}
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AST_LIST_TRAVERSE_SAFE_END
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if (!cur)
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AST_LIST_INSERT_TAIL(&con->schedq, s, list);
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con->schedcnt++;
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}
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/*! \brief
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* given the last event *tv and the offset in milliseconds 'when',
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* computes the next value,
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*/
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static int sched_settime(struct timeval *tv, int when)
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{
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struct timeval now = ast_tvnow();
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/*ast_debug(1, "TV -> %lu,%lu\n", tv->tv_sec, tv->tv_usec);*/
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if (ast_tvzero(*tv)) /* not supplied, default to now */
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*tv = now;
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*tv = ast_tvadd(*tv, ast_samp2tv(when, 1000));
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if (ast_tvcmp(*tv, now) < 0) {
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ast_debug(1, "Request to schedule in the past?!?!\n");
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*tv = now;
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}
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return 0;
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}
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int ast_sched_replace_variable(int old_id, struct sched_context *con, int when, ast_sched_cb callback, void *data, int variable)
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{
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if (old_id > -1)
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ast_sched_del(con, old_id);
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return ast_sched_add_variable(con, when, callback, data, variable);
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}
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/*! \brief
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* Schedule callback(data) to happen when ms into the future
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*/
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int ast_sched_add_variable(struct sched_context *con, int when, ast_sched_cb callback, void *data, int variable)
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{
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struct sched *tmp;
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int res = -1;
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DEBUG(ast_debug(1, "ast_sched_add()\n"));
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if (!when) {
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ast_log(LOG_NOTICE, "Scheduled event in 0 ms?\n");
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return -1;
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}
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ast_mutex_lock(&con->lock);
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if ((tmp = sched_alloc(con))) {
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tmp->id = con->eventcnt++;
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tmp->callback = callback;
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tmp->data = data;
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tmp->resched = when;
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tmp->variable = variable;
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tmp->when = ast_tv(0, 0);
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if (sched_settime(&tmp->when, when)) {
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sched_release(con, tmp);
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} else {
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schedule(con, tmp);
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res = tmp->id;
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}
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}
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#ifdef DUMP_SCHEDULER
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/* Dump contents of the context while we have the lock so nothing gets screwed up by accident. */
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if (option_debug)
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ast_sched_dump(con);
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#endif
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ast_mutex_unlock(&con->lock);
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return res;
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}
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int ast_sched_replace(int old_id, struct sched_context *con, int when, ast_sched_cb callback, void *data)
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{
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if (old_id > -1)
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ast_sched_del(con, old_id);
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return ast_sched_add(con, when, callback, data);
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}
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int ast_sched_add(struct sched_context *con, int when, ast_sched_cb callback, void *data)
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{
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return ast_sched_add_variable(con, when, callback, data, 0);
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}
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/*! \brief
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* Delete the schedule entry with number
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* "id". It's nearly impossible that there
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* would be two or more in the list with that
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* id.
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*/
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int ast_sched_del(struct sched_context *con, int id)
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{
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struct sched *s;
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DEBUG(ast_debug(1, "ast_sched_del()\n"));
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ast_mutex_lock(&con->lock);
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AST_LIST_TRAVERSE_SAFE_BEGIN(&con->schedq, s, list) {
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if (s->id == id) {
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AST_LIST_REMOVE_CURRENT(&con->schedq, list);
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con->schedcnt--;
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sched_release(con, s);
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break;
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}
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}
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AST_LIST_TRAVERSE_SAFE_END
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#ifdef DUMP_SCHEDULER
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/* Dump contents of the context while we have the lock so nothing gets screwed up by accident. */
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if (option_debug)
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ast_sched_dump(con);
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#endif
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ast_mutex_unlock(&con->lock);
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if (!s) {
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ast_debug(1, "Attempted to delete nonexistent schedule entry %d!\n", id);
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#ifdef DO_CRASH
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CRASH;
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#endif
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return -1;
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}
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return 0;
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}
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/*! \brief Dump the contents of the scheduler to LOG_DEBUG */
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void ast_sched_dump(const struct sched_context *con)
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{
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struct sched *q;
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struct timeval tv = ast_tvnow();
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#ifdef SCHED_MAX_CACHE
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ast_debug(1, "Asterisk Schedule Dump (%d in Q, %d Total, %d Cache)\n", con->schedcnt, con->eventcnt - 1, con->schedccnt);
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#else
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ast_debug(1, "Asterisk Schedule Dump (%d in Q, %d Total)\n", con->schedcnt, con->eventcnt - 1);
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#endif
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ast_debug(1, "=============================================================\n");
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ast_debug(1, "|ID Callback Data Time (sec:ms) |\n");
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ast_debug(1, "+-----+-----------------+-----------------+-----------------+\n");
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AST_LIST_TRAVERSE(&con->schedq, q, list) {
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struct timeval delta = ast_tvsub(q->when, tv);
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ast_debug(1, "|%.4d | %-15p | %-15p | %.6ld : %.6ld |\n",
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q->id,
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q->callback,
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q->data,
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delta.tv_sec,
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(long int)delta.tv_usec);
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}
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ast_debug(1, "=============================================================\n");
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}
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/*! \brief
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* Launch all events which need to be run at this time.
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*/
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int ast_sched_runq(struct sched_context *con)
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{
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struct sched *current;
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struct timeval tv;
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int numevents;
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int res;
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DEBUG(ast_debug(1, "ast_sched_runq()\n"));
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ast_mutex_lock(&con->lock);
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for (numevents = 0; !AST_LIST_EMPTY(&con->schedq); numevents++) {
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/* schedule all events which are going to expire within 1ms.
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* We only care about millisecond accuracy anyway, so this will
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* help us get more than one event at one time if they are very
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* close together.
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*/
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tv = ast_tvadd(ast_tvnow(), ast_tv(0, 1000));
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if (ast_tvcmp(AST_LIST_FIRST(&con->schedq)->when, tv) != -1)
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break;
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current = AST_LIST_REMOVE_HEAD(&con->schedq, list);
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con->schedcnt--;
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/*
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* At this point, the schedule queue is still intact. We
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* have removed the first event and the rest is still there,
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* so it's permissible for the callback to add new events, but
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* trying to delete itself won't work because it isn't in
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* the schedule queue. If that's what it wants to do, it
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* should return 0.
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*/
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ast_mutex_unlock(&con->lock);
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res = current->callback(current->data);
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ast_mutex_lock(&con->lock);
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if (res) {
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/*
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* If they return non-zero, we should schedule them to be
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* run again.
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*/
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if (sched_settime(¤t->when, current->variable? res : current->resched)) {
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sched_release(con, current);
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} else
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schedule(con, current);
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} else {
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/* No longer needed, so release it */
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sched_release(con, current);
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}
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}
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ast_mutex_unlock(&con->lock);
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return numevents;
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}
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long ast_sched_when(struct sched_context *con,int id)
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{
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struct sched *s;
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long secs = -1;
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DEBUG(ast_debug(1, "ast_sched_when()\n"));
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ast_mutex_lock(&con->lock);
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AST_LIST_TRAVERSE(&con->schedq, s, list) {
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if (s->id == id)
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break;
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}
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if (s) {
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struct timeval now = ast_tvnow();
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secs = s->when.tv_sec - now.tv_sec;
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}
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ast_mutex_unlock(&con->lock);
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return secs;
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}
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