jack1/driver.c

/*
    Copyright (C) 2001 Paul Davis
    
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU Lesser General Public License as published by
    the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
    
    You should have received a copy of the GNU Lesser General Public License
    along with this program; if not, write to the Free Software 
    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
    
    $Id$
*/

#include <string.h>
#include <stdarg.h>
#include <stdlib.h>

#include <jack/driver.h>
#include <jack/internal.h>
#include <jack/error.h>

static int dummy_attach (jack_driver_t *drv, jack_engine_t *eng) { return 0; }
static int dummy_detach (jack_driver_t *drv, jack_engine_t *eng) { return 0; }
static int dummy_wait (jack_driver_t *drv) { return 0; }
static int dummy_stop (jack_driver_t *drv) { return 0; }
static int dummy_start (jack_driver_t *drv) { return 0; }

void
jack_driver_init (jack_driver_t *driver)

{
	memset (driver, 0, sizeof (*driver));

	driver->attach = dummy_attach;
	driver->detach = dummy_detach;
	driver->wait = dummy_wait;
	driver->start = dummy_start;
	driver->stop = dummy_stop;
}

jack_driver_t *
jack_driver_load (const char *path_to_so, ...)

{
	va_list ap;
	const char *errstr;
	dlhandle handle;
	jack_driver_t *driver;
	jack_driver_t *(*initialize)(va_list);
	void (*finish)(jack_driver_t *);

	va_start (ap, path_to_so);
	handle = dlopen (path_to_so, RTLD_NOW|RTLD_GLOBAL);
	
	if (handle == 0) {
		if ((errstr = dlerror ()) != 0) {
			jack_error ("can't load \"%s\": %s", path_to_so, errstr);
		} else {
			jack_error ("bizarre error loading driver shared object %s", path_to_so);
		}
		va_end (ap);
		return 0;
	}

	initialize = dlsym (handle, "driver_initialize");

	if ((errstr = dlerror ()) != 0) {
		jack_error ("no initialize function in shared object %s\n", path_to_so);
		dlclose (handle);
		va_end (ap);
		return 0;
	}

	finish = dlsym (handle, "driver_finish");

	if ((errstr = dlerror ()) != 0) {
		jack_error ("no finish function in in shared driver object %s", path_to_so);
		dlclose (handle);
		va_end (ap);
		return 0;
	}

	if ((driver = initialize (ap)) != 0) {
		driver->handle = handle;
		driver->finish = finish;
	}

	va_end (ap);

	return driver;

}

void
jack_driver_unload (jack_driver_t *driver)
{
	driver->finish (driver);
	dlclose (driver->handle);
}