/*      $NetBSD: ev_waits.c,v 1.1.1.2 2012/09/09 16:08:02 christos Exp $        */

/*
* Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
* Copyright (c) 1996-1999 by Internet Software Consortium
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
* OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/

/* ev_waits.c - implement deferred function calls for the eventlib
* vix 05dec95 [initial]
*/

#if !defined(LINT) && !defined(CODECENTER)
static const char rcsid[] = "Id: ev_waits.c,v 1.4 2005/04/27 04:56:36 sra Exp ";
#endif

#include "port_before.h"
#include "fd_setsize.h"

#include <errno.h>

#include <isc/eventlib.h>
#include <isc/assertions.h>
#include "eventlib_p.h"

#include "port_after.h"

/* Forward. */

static void             print_waits(evContext_p *ctx);
static evWaitList *     evNewWaitList(evContext_p *);
static void             evFreeWaitList(evContext_p *, evWaitList *);
static evWaitList *     evGetWaitList(evContext_p *, const void *, int);


/* Public. */

/*%
* Enter a new wait function on the queue.
*/
int
evWaitFor(evContext opaqueCtx, const void *tag,
         evWaitFunc func, void *uap, evWaitID *id)
{
       evContext_p *ctx = opaqueCtx.opaque;
       evWait *new;
       evWaitList *wl = evGetWaitList(ctx, tag, 1);

       OKNEW(new);
       new->func = func;
       new->uap = uap;
       new->tag = tag;
       new->next = NULL;
       if (wl->last != NULL)
               wl->last->next = new;
       else
               wl->first = new;
       wl->last = new;
       if (id != NULL)
               id->opaque = new;
       if (ctx->debug >= 9)
               print_waits(ctx);
       return (0);
}

/*%
* Mark runnable all waiting functions having a certain tag.
*/
int
evDo(evContext opaqueCtx, const void *tag) {
       evContext_p *ctx = opaqueCtx.opaque;
       evWaitList *wl = evGetWaitList(ctx, tag, 0);
       evWait *first;

       if (!wl) {
               errno = ENOENT;
               return (-1);
       }

       first = wl->first;
       INSIST(first != NULL);

       if (ctx->waitDone.last != NULL)
               ctx->waitDone.last->next = first;
       else
               ctx->waitDone.first = first;
       ctx->waitDone.last = wl->last;
       evFreeWaitList(ctx, wl);

       return (0);
}

/*%
* Remove a waiting (or ready to run) function from the queue.
*/
int
evUnwait(evContext opaqueCtx, evWaitID id) {
       evContext_p *ctx = opaqueCtx.opaque;
       evWait *this, *prev;
       evWaitList *wl;
       int found = 0;

       this = id.opaque;
       INSIST(this != NULL);
       wl = evGetWaitList(ctx, this->tag, 0);
       if (wl != NULL) {
               for (prev = NULL, this = wl->first;
                    this != NULL;
                    prev = this, this = this->next)
                       if (this == (evWait *)id.opaque) {
                               found = 1;
                               if (prev != NULL)
                                       prev->next = this->next;
                               else
                                       wl->first = this->next;
                               if (wl->last == this)
                                       wl->last = prev;
                               if (wl->first == NULL)
                                       evFreeWaitList(ctx, wl);
                               break;
                       }
       }

       if (!found) {
               /* Maybe it's done */
               for (prev = NULL, this = ctx->waitDone.first;
                    this != NULL;
                    prev = this, this = this->next)
                       if (this == (evWait *)id.opaque) {
                               found = 1;
                               if (prev != NULL)
                                       prev->next = this->next;
                               else
                                       ctx->waitDone.first = this->next;
                               if (ctx->waitDone.last == this)
                                       ctx->waitDone.last = prev;
                               break;
                       }
       }

       if (!found) {
               errno = ENOENT;
               return (-1);
       }

       FREE(this);

       if (ctx->debug >= 9)
               print_waits(ctx);

       return (0);
}

int
evDefer(evContext opaqueCtx, evWaitFunc func, void *uap) {
       evContext_p *ctx = opaqueCtx.opaque;
       evWait *new;

       OKNEW(new);
       new->func = func;
       new->uap = uap;
       new->tag = NULL;
       new->next = NULL;
       if (ctx->waitDone.last != NULL)
               ctx->waitDone.last->next = new;
       else
               ctx->waitDone.first = new;
       ctx->waitDone.last = new;
       if (ctx->debug >= 9)
               print_waits(ctx);
       return (0);
}

/* Private. */

static void
print_waits(evContext_p *ctx) {
       evWaitList *wl;
       evWait *this;

       evPrintf(ctx, 9, "wait waiting:\n");
       for (wl = ctx->waitLists; wl != NULL; wl = wl->next) {
               INSIST(wl->first != NULL);
               evPrintf(ctx, 9, "  tag %p:", wl->first->tag);
               for (this = wl->first; this != NULL; this = this->next)
                       evPrintf(ctx, 9, " %p", this);
               evPrintf(ctx, 9, "\n");
       }
       evPrintf(ctx, 9, "wait done:");
       for (this = ctx->waitDone.first; this != NULL; this = this->next)
               evPrintf(ctx, 9, " %p", this);
       evPrintf(ctx, 9, "\n");
}

static evWaitList *
evNewWaitList(evContext_p *ctx) {
       evWaitList *new;

       NEW(new);
       if (new == NULL)
               return (NULL);
       new->first = new->last = NULL;
       new->prev = NULL;
       new->next = ctx->waitLists;
       if (new->next != NULL)
               new->next->prev = new;
       ctx->waitLists = new;
       return (new);
}

static void
evFreeWaitList(evContext_p *ctx, evWaitList *this) {

       INSIST(this != NULL);

       if (this->prev != NULL)
               this->prev->next = this->next;
       else
               ctx->waitLists = this->next;
       if (this->next != NULL)
               this->next->prev = this->prev;
       FREE(this);
}

static evWaitList *
evGetWaitList(evContext_p *ctx, const void *tag, int should_create) {
       evWaitList *this;

       for (this = ctx->waitLists; this != NULL; this = this->next) {
               if (this->first != NULL && this->first->tag == tag)
                       break;
       }
       if (this == NULL && should_create)
               this = evNewWaitList(ctx);
       return (this);
}

/*! \file */

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