From a134539e69be3758025cb97d13e1f282af97274a Mon Sep 17 00:00:00 2001 From: ddennedy Date: Tue, 26 Feb 2008 23:39:47 +0000 Subject: [PATCH] mlt_repository.[hc]: implement the metadata registration and lookup interface git-svn-id: https://mlt.svn.sourceforge.net/svnroot/mlt/trunk/mlt@1078 d19143bc-622f-0410-bfdd-b5b2a6649095 --- src/framework/mlt_repository.c | 46 +++++++++++++++++++++++++++++++++------- src/framework/mlt_repository.h | 25 ++++++++++++++++----- 2 files changed, 57 insertions(+), 14 deletions(-) diff --git a/src/framework/mlt_repository.c b/src/framework/mlt_repository.c index 1ac8dff..69c89eb 100644 --- a/src/framework/mlt_repository.c +++ b/src/framework/mlt_repository.c @@ -2,6 +2,7 @@ * repository.c -- provides a map between service and shared objects * Copyright (C) 2003-2004 Ushodaya Enterprises Limited * Author: Charles Yates + * Contributor: Dan Dennedy * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public @@ -73,7 +74,7 @@ mlt_repository mlt_repository_init( const char *directory ) if ( object != NULL ) { // Get the registration function - int ( *symbol_ptr )( mlt_repository ) = dlsym( object, "mlt_register" ); + mlt_repository_callback symbol_ptr = dlsym( object, "mlt_register" ); // Call the registration function if ( symbol_ptr != NULL ) @@ -90,7 +91,7 @@ mlt_repository mlt_repository_init( const char *directory ) } else if ( strstr( object_name, "libmlt" ) ) { - fprintf( stderr, "%s:%s: failed to dlopen %s\n", __FILE__, __FUNCTION__, object_name ); + fprintf( stderr, "%s, %s: failed to dlopen %s\n", __FILE__, __FUNCTION__, object_name ); } } @@ -108,7 +109,7 @@ static mlt_properties new_service( void *symbol ) Typically, this is invoked by a module within its mlt_register(). */ -void mlt_repository_register( mlt_repository this, mlt_service_type service_type, const char *service, void *symbol ) +void mlt_repository_register( mlt_repository this, mlt_service_type service_type, const char *service, mlt_register_callback symbol ) { // Add the entry point to the corresponding service list switch ( service_type ) @@ -163,8 +164,7 @@ void *mlt_repository_create( mlt_repository this, mlt_profile profile, mlt_servi mlt_properties properties = get_service_properties( this, type, service ); if ( properties != NULL ) { - void *( *symbol_ptr )( mlt_profile, mlt_service_type, const char *, void * ) = - mlt_properties_get_data( properties, "symbol", NULL ); + mlt_register_callback symbol_ptr = mlt_properties_get_data( properties, "symbol", NULL ); // Construct the service return ( symbol_ptr != NULL ) ? symbol_ptr( profile, type, service, input ) : NULL; @@ -220,17 +220,47 @@ mlt_properties mlt_repository_transitions( mlt_repository self ) /** Register the metadata for a service IMPORTANT: mlt_repository will take responsibility for deallocating the metadata properties that you supply! */ -void mlt_repository_register_metadata( mlt_repository self, mlt_service_type type, const char *service, mlt_properties metadata ) +void mlt_repository_register_metadata( mlt_repository self, mlt_service_type type, const char *service, mlt_metadata_callback callback, void *callback_data ) { mlt_properties service_properties = get_service_properties( self, type, service ); - mlt_properties_set_data( service_properties, "metadata", metadata, 0, ( mlt_destructor )mlt_properties_close, NULL ); + mlt_properties_set_data( service_properties, "metadata_cb", callback, 0, NULL, NULL ); + mlt_properties_set_data( service_properties, "metadata_cb_data", callback_data, 0, NULL, NULL ); } /** Get the metadata about a service + Returns NULL if service or its metadata are unavailable. */ mlt_properties mlt_repository_metadata( mlt_repository self, mlt_service_type type, const char *service ) { + mlt_properties metadata = NULL; mlt_properties properties = get_service_properties( self, type, service ); - return mlt_properties_get_data( properties, "metadata", NULL ); + + // If this is a valid service + if ( properties ) + { + // Lookup cached metadata + metadata = mlt_properties_get_data( properties, "metadata", NULL ); + if ( ! metadata ) + { + // Not cached, so get the registered metadata callback function + mlt_metadata_callback callback = mlt_properties_get_data( properties, "metadata_cb", NULL ); + + // If a metadata callback function is registered + if ( callback ) + { + // Fetch the callback data arg + void *data = mlt_properties_get_data( properties, "metadata_cb_data", NULL ); + + // Fetch the metadata through the callback + metadata = callback( type, service, data ); + + // Cache the metadata + if ( metadata ) + // Include dellocation and serialisation + mlt_properties_set_data( properties, "metadata", metadata, 0, ( mlt_destructor )mlt_properties_close, ( mlt_serialiser )mlt_properties_serialise_yaml ); + } + } + } + return metadata; } diff --git a/src/framework/mlt_repository.h b/src/framework/mlt_repository.h index 6517030..e7b0c67 100644 --- a/src/framework/mlt_repository.h +++ b/src/framework/mlt_repository.h @@ -2,6 +2,7 @@ * repository.h -- provides a map between service and shared objects * Copyright (C) 2003-2004 Ushodaya Enterprises Limited * Author: Charles Yates + * Contributor: Dan Dennedy * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public @@ -29,25 +30,37 @@ typedef struct mlt_repository_s *mlt_repository; -/** This macro can be used to register services if the function is declared as -* void mlt_register( mlt_repository ) +/** This callback is the main entry point into a module, which must be exported + with the symbol "mlt_register". + Inside the callback, the module registers the additional callbacks below. +*/ + +typedef void ( *mlt_repository_callback )( mlt_repository ); + +/** These are callback functions that modules implement to construct services + and metadata. +*/ +typedef void *( *mlt_register_callback )( mlt_profile, mlt_service_type, const char * /* service name */, void * /* arg */ ); +typedef mlt_properties ( *mlt_metadata_callback )( mlt_service_type, const char * /* service name */, void * /* callback_data */ ); + +/** These convenience macros can be used to register services in a more declarative manner. */ #define MLT_REPOSITORY void mlt_register( mlt_repository repository ) -#define MLT_REGISTER( type, service, symbol ) ( mlt_repository_register( repository, (type), (service), (symbol) ) ) -#define MLT_REGISTER_METADATA( type, service, properties ) ( mlt_repository_register_metadata( repository, (type), (service), (properties) ) ) +#define MLT_REGISTER( type, service, symbol ) ( mlt_repository_register( repository, (type), (service), ( mlt_register_callback )(symbol) ) ) +#define MLT_REGISTER_METADATA( type, service, callback, data ) ( mlt_repository_register_metadata( repository, (type), (service), ( mlt_metadata_callback )(callback), (data) ) ) /** Public functions. */ extern mlt_repository mlt_repository_init( const char *directory ); -extern void mlt_repository_register( mlt_repository self, mlt_service_type service_type, const char *service, void *symbol ); +extern void mlt_repository_register( mlt_repository self, mlt_service_type service_type, const char *service, mlt_register_callback ); extern void *mlt_repository_create( mlt_repository self, mlt_profile profile, mlt_service_type type, const char *service, void *arg ); extern void mlt_repository_close( mlt_repository self ); extern mlt_properties mlt_repository_consumers( mlt_repository self ); extern mlt_properties mlt_repository_filters( mlt_repository self ); extern mlt_properties mlt_repository_producers( mlt_repository self ); extern mlt_properties mlt_repository_transitions( mlt_repository self ); -extern void mlt_repository_register_metadata( mlt_repository self, mlt_service_type type, const char *service, mlt_properties metadata ); +extern void mlt_repository_register_metadata( mlt_repository self, mlt_service_type type, const char *service, mlt_metadata_callback, void *callback_data ); extern mlt_properties mlt_repository_metadata( mlt_repository self, mlt_service_type type, const char *service ); #endif -- 1.7.4.4