/**

 * $Id$

 *

 * Plugin loader code

 *

 * Copyright (c) 2009 Nathan Keynes.

 *

 * 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.

 */

#include <sys/stat.h>

#include <dirent.h>

#include <dlfcn.h>

#include <string.h>

#include <glib/gmem.h>

#include <glib/gstrfuncs.h>

#include "plugin.h"

#include "lxpaths.h"

#ifdef APPLE_BUILD

#define SOEXT ".dylib"

#else

#define SOEXT ".so"

#endif

/** Dummy plugin used as a plugin directory marker */

#define DUMMY_PLUGIN ("lxdream_dummy" SOEXT) 

const char *plugin_type_string[] = { "undefined", "audio driver", "input driver" };

int main(int argc, char *argv[]);

static const char *exec_path = NULL;

/**

 * Return the full path to the main binary

 */

static const char *get_exec_path()

{

    if( exec_path == NULL ) {

        Dl_info dli;

        /* Use dladdr for this, since it should be available for any platform

         * that we can support plugins on at all.

         */

        if( dladdr( main, &dli) ) {

            gchar *path = g_strdup( dli.dli_fname );

            char *i = strrchr( path, '/' );

            if( i > path ) {

                *i = '\0';

                exec_path = path;

            } else {

                g_free(path);

            }

        }

    }

    return exec_path;

}

static gboolean plugin_load( const gchar *plugin_path )

{

    void *so = dlopen(plugin_path, RTLD_NOW|RTLD_LOCAL);

    if( so == NULL ) {

        WARN("Failed to load plugin '%s': %s", plugin_path, dlerror());

        return FALSE;

    }

    struct plugin_struct *plugin = (struct plugin_struct *)dlsym(so,"lxdream_plugin_entry");

    if( plugin == NULL ) {

        WARN("Failed to load plugin: '%s': Not an lxdream plugin", plugin_path);

        dlclose(so);

        return FALSE;

    }

    if( strcmp(lxdream_short_version, plugin->version) != 0 ) {

        WARN("Failed to load plugin: '%s': Incompatible version (%s)", plugin_path, plugin->version);

        dlclose(so);

        return FALSE;

    }

    if( plugin->type == PLUGIN_NONE ) {

        /* 'dummy' plugin - we don't actually want to load it */

        dlclose(so);

        return FALSE;

    }

    if( plugin->type < PLUGIN_MIN_TYPE || plugin->type > PLUGIN_MAX_TYPE ) {

        WARN("Failed to load plugin: '%s': Unrecognized plugin type (%d)", plugin_path, plugin->type );

        dlclose(so);

        return FALSE;

    }

    if( plugin->register_plugin() == FALSE ) {

        WARN("Failed to load plugin: '%s': Initialization failed", plugin_path);

        dlclose(so);

        return FALSE;

    }

    DEBUG("Loaded %s '%s'", plugin_type_string[plugin->type], plugin->name);

    return TRUE;

}

static gboolean has_plugins( const gchar *path )

{

    struct stat st;

    gchar *dummy_name = g_strdup_printf( "%s/%s", path, DUMMY_PLUGIN );

    if( stat( dummy_name, &st ) == 0 ) {

        return TRUE;

    } else {

        return FALSE;

    }

}

/**

 * Scan the plugin dir and load all valid plugins.

 */

static int plugin_load_all( const gchar *plugin_dir )

{

    int plugin_count = 0;

    struct dirent *ent;

    DIR *dir = opendir(plugin_dir);

    if( dir == NULL ) {

        WARN( "Unable to open plugin directory '%s'", plugin_dir );

        return 0;

    }

    while( (ent = readdir(dir)) != NULL ) {

        const char *ext = strrchr(ent->d_name, '.');

        if( ext != NULL && strcasecmp(SOEXT,ext) == 0 ) {

            char *libname = g_strdup_printf( "%s/%s", plugin_dir,ent->d_name );

            if( plugin_load( libname ) ) {

                plugin_count++;

            }

            g_free(libname);

        }

    }

    return plugin_count;

}

int plugin_init()

{

    const char *path = get_exec_path();

    if( path == NULL || !has_plugins(path) ) {

        path = get_plugin_path();

    }

    DEBUG( "Plugin directory: %s", path );

    return plugin_load_all( path );

}