Constness changes

[melted] / src / framework / mlt_factory.c

/**
 * \file mlt_factory.c
 * \brief the factory method interfaces
 *
 * Copyright (C) 2003-2009 Ushodaya Enterprises Limited
 * \author Charles Yates <charles.yates@pandora.be>
 *
 * This library 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 library 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 library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include "mlt.h"
#include "mlt_repository.h"

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

/** the default subdirectory of the libdir for holding modules (plugins) */
#define PREFIX_LIB LIBDIR "/mlt"
/** the default subdirectory of the install prefix for holding module (plugin) data */
#define PREFIX_DATA PREFIX "/share/mlt"


/** holds the full path to the modules directory - initialized and retained for the entire session */
static char *mlt_directory = NULL;
/** a global properties list for holding environment config data and things needing session-oriented cleanup */
static mlt_properties global_properties = NULL;
/** the global repository singleton */
static mlt_repository repository = NULL;
/** the events object for the factory events */
static mlt_properties event_object = NULL;
/** for tracking the unique_id set on each constructed service */
static int unique_id = 0;

/* Event transmitters. */

/** the -create-request event transmitter
 *
 * \param listener
 * \param owner
 * \param this
 * \param args
 */

static void mlt_factory_create_request( mlt_listener listener, mlt_properties owner, mlt_service this, void **args )
{
        if ( listener != NULL )
                listener( owner, this, ( char * )args[ 0 ], ( char * )args[ 1 ], ( mlt_service * )args[ 2 ] );
}

/** the -create-done event transmitter
 *
 * \param listener
 * \param owner
 * \param this
 * \param args
 */

static void mlt_factory_create_done( mlt_listener listener, mlt_properties owner, mlt_service this, void **args )
{
        if ( listener != NULL )
                listener( owner, this, ( char * )args[ 0 ], ( char * )args[ 1 ], ( mlt_service )args[ 2 ] );
}

/** Construct the repository and factories.
 *
 * The environment variable MLT_PRODUCER is the name of a default producer often used by other services, defaults to "fezzil".
 *
 * The environment variable MLT_CONSUMER is the name of a default consumer, defaults to "sdl".
 *
 * The environment variable MLT_TEST_CARD is the name of a producer or file to be played when nothing is available (all tracks blank).
 *
 * The environment variable MLT_DATA overrides the default full path to the MLT and module supplemental data files, defaults to \p PREFIX_DATA.
 *
 * The environment variable MLT_PROFILE defaults to "dv_pal."
 *
 * The environment variable MLT_REPOSITORY overrides the default location of the plugin modules, defaults to \p PREFIX_LIB.
 *
 * \param directory an optional full path to a directory containing the modules that overrides the default and
 * the MLT_REPOSITORY environment variable
 * \return the repository
 */

mlt_repository mlt_factory_init( const char *directory )
{
        // Only initialise once
        if ( mlt_directory == NULL )
        {
                // Allow user over rides
                if ( directory == NULL || !strcmp( directory, "" ) )
                        directory = getenv( "MLT_REPOSITORY" );

                // If no directory is specified, default to install directory
                if ( directory == NULL )
                        directory = PREFIX_LIB;

                // Store the prefix for later retrieval
                mlt_directory = strdup( directory );

                // Initialise the pool
                mlt_pool_init( );

                // Create and set up the events object
                event_object = mlt_properties_new( );
                mlt_events_init( event_object );
                mlt_events_register( event_object, "producer-create-request", ( mlt_transmitter )mlt_factory_create_request );
                mlt_events_register( event_object, "producer-create-done", ( mlt_transmitter )mlt_factory_create_done );
                mlt_events_register( event_object, "filter-create-request", ( mlt_transmitter )mlt_factory_create_request );
                mlt_events_register( event_object, "filter-create-done", ( mlt_transmitter )mlt_factory_create_done );
                mlt_events_register( event_object, "transition-create-request", ( mlt_transmitter )mlt_factory_create_request );
                mlt_events_register( event_object, "transition-create-done", ( mlt_transmitter )mlt_factory_create_done );
                mlt_events_register( event_object, "consumer-create-request", ( mlt_transmitter )mlt_factory_create_request );
                mlt_events_register( event_object, "consumer-create-done", ( mlt_transmitter )mlt_factory_create_done );

                // Create the global properties
                global_properties = mlt_properties_new( );

                // Create the repository of services
                repository = mlt_repository_init( directory );

                // Force a clean up when app closes
                atexit( mlt_factory_close );
        }

        // Allow property refresh on a subsequent initialisation
        if ( global_properties != NULL )
        {
                mlt_properties_set_or_default( global_properties, "MLT_NORMALISATION", getenv( "MLT_NORMALISATION" ), "PAL" );
                mlt_properties_set_or_default( global_properties, "MLT_PRODUCER", getenv( "MLT_PRODUCER" ), "fezzik" );
                mlt_properties_set_or_default( global_properties, "MLT_CONSUMER", getenv( "MLT_CONSUMER" ), "sdl" );
                mlt_properties_set( global_properties, "MLT_TEST_CARD", getenv( "MLT_TEST_CARD" ) );
                mlt_properties_set_or_default( global_properties, "MLT_PROFILE", getenv( "MLT_PROFILE" ), "dv_pal" );
                mlt_properties_set_or_default( global_properties, "MLT_DATA", getenv( "MLT_DATA" ), PREFIX_DATA );
        }


        return repository;
}

/** Fetch the events object.
 *
 * \return the global factory event object
 */

mlt_properties mlt_factory_event_object( )
{
        return event_object;
}

/** Fetch the module directory used in this instance.
 *
 * \return the full path to the module directory that this session is using
 */

const char *mlt_factory_directory( )
{
        return mlt_directory;
}

/** Get a value from the environment.
 *
 * \param name the name of a MLT (runtime configuration) environment variable
 * \return the value of the variable
 */

char *mlt_environment( const char *name )
{
        if ( global_properties )
                return mlt_properties_get( global_properties, name );
        else
                return NULL;
}

/** Set a value in the environment.
 *
 * \param name the name of a MLT environment variable
 * \param value the value of the variable
 * \return true on error
 */

int mlt_environment_set( const char *name, const char *value )
{
        if ( global_properties )
                return mlt_properties_set( global_properties, name, value );
        else
                return -1;
}

/** Set some properties common to all services.
 *
 * This sets _unique_id, \p mlt_type, \p mlt_service (unless _mlt_service_hidden), and _profile.
 *
 * \param properties a service's properties list
 * \param profile the \p mlt_profile supplied to the factory function
 * \param type the MLT service class
 * \param service the name of the service
 */

static void set_common_properties( mlt_properties properties, mlt_profile profile, const char *type, const char *service )
{
        mlt_properties_set_int( properties, "_unique_id", ++ unique_id );
        mlt_properties_set( properties, "mlt_type", type );
        if ( mlt_properties_get_int( properties, "_mlt_service_hidden" ) == 0 )
                mlt_properties_set( properties, "mlt_service", service );
        if ( profile != NULL )
                mlt_properties_set_data( properties, "_profile", profile, 0, NULL, NULL );
}

/** Fetch a producer from the repository.
 *
 * \param profile the \p mlt_profile to use
 * \param service the name of the producer (optional, defaults to MLT_PRODUCER)
 * \param input an optional argument to the producer constructor, typically a string
 * \return a new producer
 */

mlt_producer mlt_factory_producer( mlt_profile profile, const char *service, const void *input )
{
        mlt_producer obj = NULL;

        // Pick up the default normalising producer if necessary
        if ( service == NULL )
                service = mlt_environment( "MLT_PRODUCER" );

        // Offer the application the chance to 'create'
        mlt_events_fire( event_object, "producer-create-request", service, input, &obj, NULL );

        // Try to instantiate via the specified service
        if ( obj == NULL )
        {
                obj = mlt_repository_create( repository, profile, producer_type, service, input );
                mlt_events_fire( event_object, "producer-create-done", service, input, obj, NULL );
                if ( obj != NULL )
                {
                        mlt_properties properties = MLT_PRODUCER_PROPERTIES( obj );
                        set_common_properties( properties, profile, "producer", service );
                }
        }
        return obj;
}

/** Fetch a filter from the repository.
 *
 * \param profile the \p mlt_profile to use
 * \param service the name of the filter
 * \param input an optional argument to the filter constructor, typically a string
 * \return a new filter
 */

mlt_filter mlt_factory_filter( mlt_profile profile, const char *service, const void *input )
{
        mlt_filter obj = NULL;

        // Offer the application the chance to 'create'
        mlt_events_fire( event_object, "filter-create-request", service, input, &obj, NULL );

        if ( obj == NULL )
        {
                obj = mlt_repository_create( repository, profile, filter_type, service, input );
                mlt_events_fire( event_object, "filter-create-done", service, input, obj, NULL );
        }

        if ( obj != NULL )
        {
                mlt_properties properties = MLT_FILTER_PROPERTIES( obj );
                set_common_properties( properties, profile, "filter", service );
        }
        return obj;
}

/** Fetch a transition from the repository.
 *
 * \param profile the \p mlt_profile to use
 * \param service the name of the transition
 * \param input an optional argument to the transition constructor, typically a string
 * \return a new transition
 */

mlt_transition mlt_factory_transition( mlt_profile profile, const char *service, const void *input )
{
        mlt_transition obj = NULL;

        // Offer the application the chance to 'create'
        mlt_events_fire( event_object, "transition-create-request", service, input, &obj, NULL );

        if ( obj == NULL )
        {
                obj = mlt_repository_create( repository, profile, transition_type, service, input );
                mlt_events_fire( event_object, "transition-create-done", service, input, obj, NULL );
        }

        if ( obj != NULL )
        {
                mlt_properties properties = MLT_TRANSITION_PROPERTIES( obj );
                set_common_properties( properties, profile, "transition", service );
        }
        return obj;
}

/** Fetch a consumer from the repository.
 *
 * \param profile the \p mlt_profile to use
 * \param service the name of the consumer (optional, defaults to MLT_CONSUMER)
 * \param input an optional argument to the consumer constructor, typically a string
 * \return a new consumer
 */

mlt_consumer mlt_factory_consumer( mlt_profile profile, const char *service, const void *input )
{
        mlt_consumer obj = NULL;

        if ( service == NULL )
                service = mlt_environment( "MLT_CONSUMER" );

        // Offer the application the chance to 'create'
        mlt_events_fire( event_object, "consumer-create-request", service, input, &obj, NULL );

        if ( obj == NULL )
        {
                obj = mlt_repository_create( repository, profile, consumer_type, service, input );
                mlt_events_fire( event_object, "consumer-create-done", service, input, obj, NULL );
        }

        if ( obj != NULL )
        {
                mlt_properties properties = MLT_CONSUMER_PROPERTIES( obj );
                set_common_properties( properties, profile, "consumer", service );
        }
        return obj;
}

/** Register an object for clean up.
 *
 * \param ptr an opaque pointer to anything allocated on the heap
 * \param destructor the function pointer of the deallocation subroutine (e.g., free or \p mlt_pool_release)
 */

void mlt_factory_register_for_clean_up( void *ptr, mlt_destructor destructor )
{
        char unique[ 256 ];
        sprintf( unique, "%08d", mlt_properties_count( global_properties ) );
        mlt_properties_set_data( global_properties, unique, ptr, 0, destructor, NULL );
}

/** Close the factory.
 *
 * Cleanup all resources for the session.
 */

void mlt_factory_close( )
{
        if ( mlt_directory != NULL )
        {
                mlt_properties_close( event_object );
                mlt_properties_close( global_properties );
                mlt_repository_close( repository );
                free( mlt_directory );
                mlt_directory = NULL;
                mlt_pool_close( );
        }
}

mlt_properties mlt_global_properties( )
{
        return global_properties;
}