/*
 * $Id: event.c,v 1.24.2.1 1999/07/07 01:46:44 wessels Exp $
 *
 * DEBUG: section 41    Event Processing
 * AUTHOR: Henrik Nordstrom
 *
 * SQUID Internet Object Cache  http://squid.nlanr.net/Squid/
 * ----------------------------------------------------------
 *
 *  Squid is the result of efforts by numerous individuals from the
 *  Internet community.  Development is led by Duane Wessels of the
 *  National Laboratory for Applied Network Research and funded by the
 *  National Science Foundation.  Squid is Copyrighted (C) 1998 by
 *  Duane Wessels and the University of California San Diego.  Please
 *  see the COPYRIGHT file for full details.  Squid incorporates
 *  software developed and/or copyrighted by other sources.  Please see
 *  the CREDITS file for full details.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *  
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *  
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
 *
 */

#include "squid.h"

/* The list of event processes */
struct ev_entry {
    EVH *func;
    void *arg;
    const char *name;
    double when;
    struct ev_entry *next;
    int weight;
    int id;
};

static struct ev_entry *tasks = NULL;
static OBJH eventDump;
static int run_id = 0;

void
eventAdd(const char *name, EVH * func, void *arg, double when, int weight)
{
    struct ev_entry *event = xcalloc(1, sizeof(struct ev_entry));
    struct ev_entry **E;
    event->func = func;
    event->arg = arg;
    event->name = name;
    event->when = current_dtime + when;
    event->weight = weight;
    event->id = run_id;
    if (NULL != arg)
	cbdataLock(arg);
    debug(41, 7) ("eventAdd: Adding '%s', in %f seconds\n", name, when);
    /* Insert after the last event with the same or earlier time */
    for (E = &tasks; *E; E = &(*E)->next) {
	if ((*E)->when > event->when)
	    break;
    }
    event->next = *E;
    *E = event;
}

/* same as eventAdd but adds a random offset within +-1/3 of delta_ish */
void
eventAddIsh(const char *name, EVH * func, void *arg, double delta_ish, int weight)
{
    if (delta_ish >= 3.0) {
	const double two_third = (2.0 * delta_ish) / 3.0;
	delta_ish = two_third + (drand48() * two_third);
	/*
	 * I'm sure drand48() isn't portable.  Tell me what function
	 * you have that returns a random double value in the range 0,1.
	 */
    }
    eventAdd(name, func, arg, delta_ish, weight);
}

void
eventDelete(EVH * func, void *arg)
{
    struct ev_entry **E;
    struct ev_entry *event;
    for (E = &tasks; (event = *E) != NULL; E = &(*E)->next) {
	if (event->func != func)
	    continue;
	if (event->arg != arg)
	    continue;
	*E = event->next;
	if (NULL != event->arg)
	    cbdataUnlock(event->arg);
	xfree(event);
	return;
    }
    debug_trap("eventDelete: event not found");
}

void
eventRun(void)
{
    struct ev_entry *event = NULL;
    EVH *func;
    void *arg;
    int weight = 0;
    if (NULL == tasks)
	return;
    if (tasks->when > current_dtime)
	return;
    run_id++;
    debug(41, 5) ("eventRun: RUN ID %d\n", run_id);
    while ((event = tasks)) {
	if (event->when > current_dtime)
	    break;
	if (event->id == run_id)	/* was added during this run */
	    break;
	if (weight)
	    break;
	func = event->func;
	arg = event->arg;
	event->func = NULL;
	event->arg = NULL;
	tasks = event->next;
	if (NULL != arg) {
	    int valid = cbdataValid(arg);
	    cbdataUnlock(arg);
	    if (!valid) {
		safe_free(event);
		return;
	    }
	}
	weight += event->weight;
	debug(41, 5) ("eventRun: Running '%s', id %d\n", event->name, event->id);
	func(arg);
	safe_free(event);
    }
}

time_t
eventNextTime(void)
{
    if (!tasks)
	return (time_t) 10;
    return (time_t) ((tasks->when - current_dtime) * 1000);
}

void
eventInit(void)
{
    cachemgrRegister("events",
	"Event Queue",
	eventDump, 0, 1);
}

static void
eventDump(StoreEntry * sentry)
{
    struct ev_entry *e = tasks;
    storeAppendPrintf(sentry, "%s\t%s\n",
	"Operation",
	"Next Execution");
    while (e != NULL) {
	storeAppendPrintf(sentry, "%s\t%f seconds\n",
	    e->name, e->when - current_dtime);
	e = e->next;
    }
}

void
eventFreeMemory(void)
{
    struct ev_entry *event;
    while ((event = tasks)) {
	if (NULL != event->arg)
	    cbdataUnlock(event->arg);
	xfree(event);
    }
    tasks = NULL;
}

int
eventFind(EVH * func, void *arg)
{
    struct ev_entry *event;
    for (event = tasks; event != NULL; event = event->next) {
	if (event->func == func && event->arg == arg)
	    return 1;
    }
    return 0;
}