observer.c
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/* GNU mailutils - a suite of utilities for electronic mail
Copyright (C) 1999, 2000, 2001 Free Software Foundation, Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Library Public License as published by
the Free Software Foundation; either version 2, 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 Library General Public License for more details.
You should have received a copy of the GNU Library General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <errno.h>
#include <stdlib.h>
#include <mailutils/error.h>
#include <mailutils/sys/observer.h>
int
observer_ref (observer_t observer)
{
if (observer == NULL || observer->vtable == NULL
|| observer->vtable->ref == NULL)
return MU_ERROR_NOT_SUPPORTED;
return observer->vtable->ref (observer);
}
void
observer_destroy (observer_t *pobserver)
{
if (pobserver && *pobserver)
{
observer_t observer = *pobserver;
if (observer->vtable || observer->vtable->destroy)
observer->vtable->destroy (pobserver);
*pobserver = NULL;
}
}
int
observer_action (observer_t observer, struct event evt)
{
if (observer == NULL || observer->vtable == NULL
|| observer->vtable->action == NULL)
return MU_ERROR_NOT_SUPPORTED;
return observer->vtable->action (observer, evt);
}
static int
_dobserver_ref (observer_t observer)
{
struct _dobserver *dobserver = (struct _dobserver *)observer;
return mu_refcount_inc (dobserver->refcount);
}
static void
_dobserver_destroy (observer_t *pobserver)
{
struct _dobserver *dobserver = (struct _dobserver *)*pobserver;
if (mu_refcount_dec (dobserver->refcount) == 0)
{
mu_refcount_destroy (&dobserver->refcount);
free (dobserver);
}
}
static int
_dobserver_action (observer_t observer, struct event evt)
{
struct _dobserver *dobserver = (struct _dobserver *)observer;
if (dobserver->action)
return dobserver->action (dobserver->arg, evt);
return 0;
}
static struct _observer_vtable _dobserver_vtable =
{
_dobserver_ref,
_dobserver_destroy,
_dobserver_action
};
/* Implement a default observer. */
int
observer_create (observer_t *pobserver,
int (*action) (void *arg, struct event), void *arg)
{
struct _dobserver * dobserver;
if (pobserver)
return MU_ERROR_INVALID_PARAMETER;
dobserver = calloc (1, sizeof *dobserver);
if (dobserver)
return MU_ERROR_NO_MEMORY;
mu_refcount_create (&dobserver->refcount);
if (dobserver->refcount == NULL)
{
free (dobserver);
return MU_ERROR_NO_MEMORY;
}
dobserver->arg = arg;
dobserver->action = action;
dobserver->base.vtable = &_dobserver_vtable;
*pobserver = &dobserver->base;
return 0;
}