[melted] / src / framework / mlt_repository.c

/*
 * repository.c -- provides a map between service and shared objects
 * Copyright (C) 2003-2004 Ushodaya Enterprises Limited
 * Author: Charles Yates <charles.yates@pandora.be>
 *
 * 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 02111-1307, USA.
 */

#include "mlt_repository.h"
#include "mlt_properties.h"

#include <stdio.h>
#include <stdlib.h>
#include <dlfcn.h>
#include <string.h>

struct mlt_repository_s
{
        struct mlt_properties_s parent;
};

static char *construct_full_file( char *output, char *prefix, char *file )
{
        strcpy( output, prefix );
        if ( prefix[ strlen( prefix ) - 1 ] != '/' )
                strcat( output, "/" );
        strcat( output, file );
        return output;
}

static char *chomp( char *input )
{
        if ( input[ strlen( input ) - 1 ] == '\n' )
                input[ strlen( input ) - 1 ] = '\0';
        return input;
}

static mlt_properties construct_object( char *prefix, char *id )
{
        mlt_properties output = mlt_properties_new( );
        mlt_properties_set( output, "prefix", prefix );
        mlt_properties_set( output, "id", id );
        return output;
}

static mlt_properties construct_service( mlt_properties object, char *id )
{
        mlt_properties output = mlt_properties_new( );
        mlt_properties_set_data( output, "object", object, 0, NULL, NULL );
        mlt_properties_set( output, "id", id );
        return output;
}

static void *construct_instance( mlt_properties service_properties, char *symbol, void *input )
{
        // Extract the service
        char *service = mlt_properties_get( service_properties, "id" );

        // Get the object properties
        void *object_properties = mlt_properties_get_data( service_properties, "object", NULL );

        // Get the dlopen'd object
        void *object = mlt_properties_get_data( object_properties, "dlopen", NULL );

        // Get the dlsym'd symbol
        void *( *symbol_ptr )( char *, void * ) = mlt_properties_get_data( object_properties, symbol, NULL );

        // Check that we have object and open if we don't
        if ( object == NULL )
        {
                char full_file[ 512 ];

                // Get the prefix and id of the shared object
                char *prefix = mlt_properties_get( object_properties, "prefix" );
                char *file = mlt_properties_get( object_properties, "id" );

                // Construct the full file
                construct_full_file( full_file, prefix, file );

                // Open the shared object
                object = dlopen( full_file, RTLD_NOW );
                if ( object != NULL )
                {
                        // Set it on the properties
                        mlt_properties_set_data( object_properties, "dlopen", object, 0, ( mlt_destructor )dlclose, NULL );
                }
                else
                {
                        fprintf( stderr, "Failed to load plugin: %s\n", dlerror() );
                }
        }

        // Now check if we have this symbol pointer
        if ( object != NULL && symbol_ptr == NULL )
        {
                // Construct it now
                symbol_ptr = dlsym( object, symbol );

                // Set it on the properties
                mlt_properties_set_data( object_properties, "dlsym", symbol_ptr, 0, NULL, NULL );
        }

        // Construct the service
        return symbol_ptr != NULL ? symbol_ptr( service, input ) : NULL;
}

mlt_repository mlt_repository_init( mlt_properties object_list, char *prefix, char *data, char *symbol )
{
        char full_file[ 512 ];
        FILE *file;

        // Construct the repository
        mlt_repository this = calloc( sizeof( struct mlt_repository_s ), 1 );
        mlt_properties_init( &this->parent, this );

        // Add the symbol to THIS repository properties.
        mlt_properties_set( &this->parent, "_symbol", symbol );

        // Construct full file
        construct_full_file( full_file, prefix, data );

        // Open the file
        file = fopen( full_file, "r" );

        // Parse the contents
        if ( file != NULL )
        {
                char full[ 512 ];
                char service[ 256 ];
                char object[ 256 ];

                while( fgets( full, 512, file ) )
                {
                        chomp( full );

                        if ( full[ 0 ] != '#' && full[ 0 ] != '\0' && sscanf( full, "%s %s", service, object ) == 2 )
                        {
                                // Get the object properties first
                                mlt_properties object_properties = mlt_properties_get_data( object_list, object, NULL );

                                // If their are no properties, create them now
                                if ( object_properties == NULL )
                                {
                                        // Construct the object
                                        object_properties = construct_object( prefix, object );

                                        // Add it to the object list
                                        mlt_properties_set_data( object_list, object, object_properties, 0, ( mlt_destructor )mlt_properties_close, NULL );
                                }

                                // Now construct a property for the service
                                mlt_properties service_properties = construct_service( object_properties, service );

                                // Add it to the repository
                                mlt_properties_set_data( &this->parent, service, service_properties, 0, ( mlt_destructor )mlt_properties_close, NULL );
                        }
                }

                // Close the file
                fclose( file );
        }

        return this;
}

void *mlt_repository_fetch( mlt_repository this, char *service, void *input )
{
        // Get the service properties
        mlt_properties service_properties = mlt_properties_get_data( &this->parent, service, NULL );

        // If the service exists
        if ( service_properties != NULL )
        {
                // Get the symbol that is used to generate this service
                char *symbol = mlt_properties_get( &this->parent, "_symbol" );

                // Now get an instance of the service
                return construct_instance( service_properties, symbol, input );
        }

        return NULL;
}

void mlt_repository_close( mlt_repository this )
{
        mlt_properties_close( &this->parent );
        free( this );
}