Constness changes

[melted] / src / framework / mlt_service.c

/**
 * \file mlt_service.c
 * \brief interface definition for all service classes
 * \see mlt_service_s
 *
 * 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_service.h"
#include "mlt_filter.h"
#include "mlt_frame.h"
#include "mlt_cache.h"
#include "mlt_factory.h"
#include "mlt_log.h"

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


/*  IMPORTANT NOTES

        The base service implements a null frame producing service - as such,
        it is functional without extension and will produce test cards frames
        and PAL sized audio frames.

        PLEASE DO NOT CHANGE THIS BEHAVIOUR!!! OVERRIDE THE METHODS THAT
        CONTROL THIS IN EXTENDING CLASSES.
*/

/** \brief private service definition */

typedef struct
{
        int size;
        int count;
        mlt_service *in;
        mlt_service out;
        int filter_count;
        int filter_size;
        mlt_filter *filters;
        pthread_mutex_t mutex;
}
mlt_service_base;

/* Private methods
 */

static void mlt_service_disconnect( mlt_service this );
static void mlt_service_connect( mlt_service this, mlt_service that );
static int service_get_frame( mlt_service this, mlt_frame_ptr frame, int index );
static void mlt_service_property_changed( mlt_listener, mlt_properties owner, mlt_service this, void **args );
static void purge_cache( mlt_service self );

/** Initialize a service.
 *
 * \public \memberof mlt_service_s
 * \param this the service structure to initialize
 * \param child pointer to the child object for the subclass
 * \return true if there was an error
 */

int mlt_service_init( mlt_service this, void *child )
{
        int error = 0;

        // Initialise everything to NULL
        memset( this, 0, sizeof( struct mlt_service_s ) );

        // Assign the child
        this->child = child;

        // Generate local space
        this->local = calloc( sizeof( mlt_service_base ), 1 );

        // Associate the methods
        this->get_frame = service_get_frame;

        // Initialise the properties
        error = mlt_properties_init( &this->parent, this );
        if ( error == 0 )
        {
                this->parent.close = ( mlt_destructor )mlt_service_close;
                this->parent.close_object = this;

                mlt_events_init( &this->parent );
                mlt_events_register( &this->parent, "service-changed", NULL );
                mlt_events_register( &this->parent, "property-changed", ( mlt_transmitter )mlt_service_property_changed );
                pthread_mutex_init( &( ( mlt_service_base * )this->local )->mutex, NULL );
        }

        return error;
}

/** The transmitter for property changes.
 *
 * Invokes the listener.
 *
 * \private \memberof mlt_service_s
 * \param listener a function pointer that will be invoked
 * \param owner a properties list that will be passed to \p listener
 * \param this a service that will be passed to \p listener
 * \param args an array of pointers - the first entry is passed as a string to \p listener
 */

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

/** Acquire a mutual exclusion lock on this service.
 *
 * \public \memberof mlt_service_s
 * \param this the service to lock
 */

void mlt_service_lock( mlt_service this )
{
        if ( this != NULL )
                pthread_mutex_lock( &( ( mlt_service_base * )this->local )->mutex );
}

/** Release a mutual exclusion lock on this service.
 *
 * \public \memberof mlt_service_s
 * \param this the service to unlock
 */

void mlt_service_unlock( mlt_service this )
{
        if ( this != NULL )
                pthread_mutex_unlock( &( ( mlt_service_base * )this->local )->mutex );
}

/** Identify the subclass of the service.
 *
 * \public \memberof mlt_service_s
 * \param this a service
 * \return the subclass
 */

mlt_service_type mlt_service_identify( mlt_service this )
{
        mlt_service_type type = invalid_type;
        if ( this != NULL )
        {
                mlt_properties properties = MLT_SERVICE_PROPERTIES( this );
                char *mlt_type = mlt_properties_get( properties, "mlt_type" );
                char *resource = mlt_properties_get( properties, "resource" );
                if ( mlt_type == NULL )
                        type = unknown_type;
                else if (resource != NULL && !strcmp( resource, "<playlist>" ) )
                        type = playlist_type;
                else if (resource != NULL && !strcmp( resource, "<tractor>" ) )
                        type = tractor_type;
                else if (resource != NULL && !strcmp( resource, "<multitrack>" ) )
                        type = multitrack_type;
                else if ( !strcmp( mlt_type, "producer" ) )
                        type = producer_type;
                else if ( !strcmp( mlt_type, "filter" ) )
                        type = filter_type;
                else if ( !strcmp( mlt_type, "transition" ) )
                        type = transition_type;
                else if ( !strcmp( mlt_type, "consumer" ) )
                        type = consumer_type;
                else
                        type = unknown_type;
        }
        return type;
}

/** Connect a producer to the service.
 *
 * \public \memberof mlt_service_s
 * \param this a service
 * \param producer a producer
 * \param index which of potentially multiple producers to this service (0 based)
 * \return > 0 warning, == 0 success, < 0 serious error,
 *         1 = this service does not accept input,
 *         2 = the producer is invalid,
 *         3 = the producer is already registered with this consumer
 */

int mlt_service_connect_producer( mlt_service this, mlt_service producer, int index )
{
        int i = 0;

        // Get the service base
        mlt_service_base *base = this->local;

        // Special case 'track' index - only works for last filter(s) in a particular chain
        // but allows a filter to apply to the output frame regardless of which track it comes from
        if ( index == -1 )
                index = 0;

        // Check if the producer is already registered with this service
        for ( i = 0; i < base->count; i ++ )
                if ( base->in[ i ] == producer )
                        return 3;

        // Allocate space
        if ( index >= base->size )
        {
                int new_size = base->size + index + 10;
                base->in = realloc( base->in, new_size * sizeof( mlt_service ) );
                if ( base->in != NULL )
                {
                        for ( i = base->size; i < new_size; i ++ )
                                base->in[ i ] = NULL;
                        base->size = new_size;
                }
        }

        // If we have space, assign the input
        if ( base->in != NULL && index >= 0 && index < base->size )
        {
                // Get the current service
                mlt_service current = base->in[ index ];

                // Increment the reference count on this producer
                if ( producer != NULL )
                        mlt_properties_inc_ref( MLT_SERVICE_PROPERTIES( producer ) );

                // Now we disconnect the producer service from its consumer
                mlt_service_disconnect( producer );

                // Add the service to index specified
                base->in[ index ] = producer;

                // Determine the number of active tracks
                if ( index >= base->count )
                        base->count = index + 1;

                // Now we connect the producer to its connected consumer
                mlt_service_connect( producer, this );

                // Close the current service
                mlt_service_close( current );

                // Inform caller that all went well
                return 0;
        }
        else
        {
                return -1;
        }
}

/** Disconnect this service from its consumer.
 *
 * \public \memberof mlt_service_s
 * \param this a service
 */

static void mlt_service_disconnect( mlt_service this )
{
        if ( this != NULL )
        {
                // Get the service base
                mlt_service_base *base = this->local;

                // Disconnect
                base->out = NULL;
        }
}

/** Obtain the consumer this service is connected to.
 *
 * \public \memberof mlt_service_s
 * \param this a service
 * \return the consumer
 */

mlt_service mlt_service_consumer( mlt_service this )
{
        // Get the service base
        mlt_service_base *base = this->local;

        // Return the connected consumer
        return base->out;
}

/** Obtain the producer this service is connected to.
 *
 * \public \memberof mlt_service_s
 * \param this a service
 * \return the last-most producer
 */

mlt_service mlt_service_producer( mlt_service this )
{
        // Get the service base
        mlt_service_base *base = this->local;

        // Return the connected producer
        return base->count > 0 ? base->in[ base->count - 1 ] : NULL;
}

/** Associate this service to a consumer.
 *
 * Overwrites connection to any existing consumer.
 * \private \memberof mlt_service_s
 * \param this a service
 * \param that a consumer
 */

static void mlt_service_connect( mlt_service this, mlt_service that )
{
        if ( this != NULL )
        {
                // Get the service base
                mlt_service_base *base = this->local;

                // There's a bit more required here...
                base->out = that;
        }
}

/** Get the first connected producer.
 *
 * \public \memberof mlt_service_s
 * \param this a service
 * \return the first producer
 */

mlt_service mlt_service_get_producer( mlt_service this )
{
        mlt_service producer = NULL;

        // Get the service base
        mlt_service_base *base = this->local;

        if ( base->in != NULL )
                producer = base->in[ 0 ];

        return producer;
}

/** Default implementation of the get_frame virtual function.
 *
 * \private \memberof mlt_service_s
 * \param this a service
 * \param[out] frame a frame by reference
 * \param index as determined by the producer
 * \return false
 */

static int service_get_frame( mlt_service this, mlt_frame_ptr frame, int index )
{
        mlt_service_base *base = this->local;
        if ( index < base->count )
        {
                mlt_service producer = base->in[ index ];
                if ( producer != NULL )
                        return mlt_service_get_frame( producer, frame, index );
        }
        *frame = mlt_frame_init( this );
        return 0;
}

/** Return the properties object.
 *
 * \public \memberof mlt_service_s
 * \param this a service
 * \return the properties
 */

mlt_properties mlt_service_properties( mlt_service this )
{
        return this != NULL ? &this->parent : NULL;
}

/** Recursively apply attached filters.
 *
 * \public \memberof mlt_service_s
 * \param this a service
 * \param frame a frame
 * \param index used to track depth of recursion, top caller should supply 0
 */

void mlt_service_apply_filters( mlt_service this, mlt_frame frame, int index )
{
        int i;
        mlt_properties frame_properties = MLT_FRAME_PROPERTIES( frame );
        mlt_properties service_properties = MLT_SERVICE_PROPERTIES( this );
        mlt_service_base *base = this->local;
        mlt_position position = mlt_frame_get_position( frame );
        mlt_position this_in = mlt_properties_get_position( service_properties, "in" );
        mlt_position this_out = mlt_properties_get_position( service_properties, "out" );

        if ( index == 0 || mlt_properties_get_int( service_properties, "_filter_private" ) == 0 )
        {
                // Process the frame with the attached filters
                for ( i = 0; i < base->filter_count; i ++ )
                {
                        if ( base->filters[ i ] != NULL )
                        {
                                mlt_position in = mlt_filter_get_in( base->filters[ i ] );
                                mlt_position out = mlt_filter_get_out( base->filters[ i ] );
                                int disable = mlt_properties_get_int( MLT_FILTER_PROPERTIES( base->filters[ i ] ), "disable" );
                                if ( !disable && ( ( in == 0 && out == 0 ) || ( position >= in && ( position <= out || out == 0 ) ) ) )
                                {
                                        mlt_properties_set_position( frame_properties, "in", in == 0 ? this_in : in );
                                        mlt_properties_set_position( frame_properties, "out", out == 0 ? this_out : out );
                                        mlt_filter_process( base->filters[ i ], frame );
                                        mlt_service_apply_filters( MLT_FILTER_SERVICE( base->filters[ i ] ), frame, index + 1 );
                                }
                        }
                }
        }
}

/** Obtain a frame.
 *
 * \public \memberof mlt_service_s
 * \param this a service
 * \param[out] frame a frame by reference
 * \param index as determined by the producer
 * \return true if there was an error
 */

int mlt_service_get_frame( mlt_service this, mlt_frame_ptr frame, int index )
{
        int result = 0;

        // Lock the service
        mlt_service_lock( this );

        // Ensure that the frame is NULL
        *frame = NULL;

        // Only process if we have a valid service
        if ( this != NULL && this->get_frame != NULL )
        {
                mlt_properties properties = MLT_SERVICE_PROPERTIES( this );
                mlt_position in = mlt_properties_get_position( properties, "in" );
                mlt_position out = mlt_properties_get_position( properties, "out" );

                result = this->get_frame( this, frame, index );

                if ( result == 0 )
                {
                        mlt_properties_inc_ref( properties );
                        properties = MLT_FRAME_PROPERTIES( *frame );
                        if ( in >=0 && out > 0 )
                        {
                                mlt_properties_set_position( properties, "in", in );
                                mlt_properties_set_position( properties, "out", out );
                        }
                        mlt_service_apply_filters( this, *frame, 1 );
                        mlt_deque_push_back( MLT_FRAME_SERVICE_STACK( *frame ), this );
                }
        }

        // Make sure we return a frame
        if ( *frame == NULL )
                *frame = mlt_frame_init( this );

        // Unlock the service
        mlt_service_unlock( this );

        return result;
}

/** The service-changed event handler.
 *
 * \private \memberof mlt_service_s
 * \param owner ignored
 * \param this the service on which the "service-changed" event is fired
 */

static void mlt_service_filter_changed( mlt_service owner, mlt_service this )
{
        mlt_events_fire( MLT_SERVICE_PROPERTIES( this ), "service-changed", NULL );
}

/** Attach a filter.
 *
 * \public \memberof mlt_service_s
 * \param this a service
 * \param filter the filter to attach
 * \return true if there was an error
 */

int mlt_service_attach( mlt_service this, mlt_filter filter )
{
        int error = this == NULL || filter == NULL;
        if ( error == 0 )
        {
                int i = 0;
                mlt_properties properties = MLT_SERVICE_PROPERTIES( this );
                mlt_service_base *base = this->local;

                for ( i = 0; error == 0 && i < base->filter_count; i ++ )
                        if ( base->filters[ i ] == filter )
                                error = 1;

                if ( error == 0 )
                {
                        if ( base->filter_count == base->filter_size )
                        {
                                base->filter_size += 10;
                                base->filters = realloc( base->filters, base->filter_size * sizeof( mlt_filter ) );
                        }

                        if ( base->filters != NULL )
                        {
                                mlt_properties props = MLT_FILTER_PROPERTIES( filter );
                                mlt_properties_inc_ref( MLT_FILTER_PROPERTIES( filter ) );
                                base->filters[ base->filter_count ++ ] = filter;
                                mlt_events_fire( properties, "service-changed", NULL );
                                mlt_events_listen( props, this, "service-changed", ( mlt_listener )mlt_service_filter_changed );
                                mlt_events_listen( props, this, "property-changed", ( mlt_listener )mlt_service_filter_changed );
                        }
                        else
                        {
                                error = 2;
                        }
                }
        }
        return error;
}

/** Detach a filter.
 *
 * \public \memberof mlt_service_s
 * \param this a service
 * \param filter the filter to detach
 * \return true if there was an error
 */

int mlt_service_detach( mlt_service this, mlt_filter filter )
{
        int error = this == NULL || filter == NULL;
        if ( error == 0 )
        {
                int i = 0;
                mlt_service_base *base = this->local;
                mlt_properties properties = MLT_SERVICE_PROPERTIES( this );

                for ( i = 0; i < base->filter_count; i ++ )
                        if ( base->filters[ i ] == filter )
                                break;

                if ( i < base->filter_count )
                {
                        base->filters[ i ] = NULL;
                        for ( i ++ ; i < base->filter_count; i ++ )
                                base->filters[ i - 1 ] = base->filters[ i ];
                        base->filter_count --;
                        mlt_events_disconnect( MLT_FILTER_PROPERTIES( filter ), this );
                        mlt_filter_close( filter );
                        mlt_events_fire( properties, "service-changed", NULL );
                }
        }
        return error;
}

/** Retrieve a filter.
 *
 * \public \memberof mlt_service_s
 * \param this a service
 * \param index which one of potentially multiple filters
 * \return the filter or null if there was an error
 */

mlt_filter mlt_service_filter( mlt_service this, int index )
{
        mlt_filter filter = NULL;
        if ( this != NULL )
        {
                mlt_service_base *base = this->local;
                if ( index >= 0 && index < base->filter_count )
                        filter = base->filters[ index ];
        }
        return filter;
}

/** Retrieve the profile.
 *
 * \public \memberof mlt_service_s
 * \param this a service
 * \return the profile
 */

mlt_profile mlt_service_profile( mlt_service this )
{
        return mlt_properties_get_data( MLT_SERVICE_PROPERTIES( this ), "_profile", NULL );
}

/** Destroy a service.
 *
 * \public \memberof mlt_service_s
 * \param this the service to destroy
 */

void mlt_service_close( mlt_service this )
{
        if ( this != NULL && mlt_properties_dec_ref( MLT_SERVICE_PROPERTIES( this ) ) <= 0 )
        {
                if ( this->close != NULL )
                {
                        this->close( this->close_object );
                }
                else
                {
                        mlt_service_base *base = this->local;
                        int i = 0;
                        int count = base->filter_count;
                        mlt_events_block( MLT_SERVICE_PROPERTIES( this ), this );
                        while( count -- )
                                mlt_service_detach( this, base->filters[ 0 ] );
                        free( base->filters );
                        for ( i = 0; i < base->count; i ++ )
                                if ( base->in[ i ] != NULL )
                                        mlt_service_close( base->in[ i ] );
                        this->parent.close = NULL;
                        free( base->in );
                        pthread_mutex_destroy( &base->mutex );
                        free( base );
                        purge_cache( this );
                        mlt_properties_close( &this->parent );
                }
        }
        else
        {
                mlt_service_unlock( this );
        }
}

/** Release a service's cache items.
 *
 * \private \memberof mlt_service_s
 * \param self a service
 */

static void purge_cache( mlt_service self )
{
        mlt_properties caches = mlt_properties_get_data( mlt_global_properties(), "caches", NULL );

        if ( caches )
        {
                int i = mlt_properties_count( caches );
                while ( i-- )
                {
                        mlt_cache_purge( mlt_properties_get_data_at( caches, i, NULL ), self );
                        mlt_properties_set_data( mlt_global_properties(), mlt_properties_get_name( caches, i ), NULL, 0, NULL, NULL );
                }
        }
}

/** Lookup the cache object for a service.
 *
 * \private \memberof mlt_service_s
 * \param self a service
 * \param name a name for the object
 * \return a cache
 */

static mlt_cache get_cache( mlt_service self, const char *name )
{
        mlt_cache result = NULL;
        mlt_properties caches = mlt_properties_get_data( mlt_global_properties(), "caches", NULL );

        if ( !caches )
        {
                caches = mlt_properties_new();
                mlt_properties_set_data( mlt_global_properties(), "caches", caches, 0, ( mlt_destructor )mlt_properties_close, NULL );
        }
        if ( caches )
        {
                result = mlt_properties_get_data( caches, name, NULL );
                if ( !result )
                {
                        result = mlt_cache_init();
                        mlt_properties_set_data( caches, name, result, 0, ( mlt_destructor )mlt_cache_close, NULL );
                }
        }
        
        return result;
}

/** Put an object into a service's cache.
 *
 * \public \memberof mlt_service_s
 * \param self a service
 * \param name a name for the object that is unique to the service class, but not to the instance
 * \param data an opaque pointer to the object to put into the cache
 * \param size the number of bytes pointed to by data
 * \param destructor a function that releases the data
 */

void mlt_service_cache_put( mlt_service self, const char *name, void* data, int size, mlt_destructor destructor )
{
        mlt_log( self, MLT_LOG_DEBUG, "%s: name %s object %p data %p\n", __FUNCTION__, name, self, data );
        mlt_cache cache = get_cache( self, name );

        if ( cache )
                mlt_cache_put( cache, self, data, size, destructor );
}

/** Get an object from a service's cache.
 *
 * \public \memberof mlt_service_s
 * \param self a service
 * \param name a name for the object that is unique to the service class, but not to the instance
 * \return a cache item or NULL if an object is not found
 * \see mlt_cache_item_data
 */

mlt_cache_item mlt_service_cache_get( mlt_service self, const char *name )
{
        mlt_log( self, MLT_LOG_DEBUG, "%s: name %s object %p\n", __FUNCTION__, name, self );
        mlt_cache_item result = NULL;
        mlt_cache cache = get_cache( self, name );

        if ( cache )
                result = mlt_cache_get( cache, self );

        return result;
}