Converter for ez4 template-objects to twig templates

gistfile1.php

<?php

class ForwardAdapter
{
    private $object;

    private $properties;

    private $staticproperties;

    /**
     * Constructor, takes as input an "eZ4 template object".
     * Those had no interface defined, but have to implement 3 methods:
     * hasAttribute, attriubute and attributes
     *
     * @todo check that $transferredObject implements the appropraite interface...
     */
    public function __construct( $transferredObject )
    {
        $this->object = $transferredObject;
    }

    /**
     * This is implemented to allow the Twig tpl engine to access the "properties"
     * of the eZ4 object. Twig likes "__call()", but does know squat about "attribute()"
     */
    public function __call( $name, $args )
    {
        // cache this for speed
        if ( !is_array( $this->properties ) )
        {
            // list all of the existing attributes
            $this->properties = array_flip( $this->object->attributes() );
            // list of all attributes which do not needa  closure
            if ( is_callable( array( $this->object, 'definition' ) )
            {
                $def = $this->object->definition();
                foreach( $def['fields'] as $attrname => $fielddesc )
                {
                    $this->staticproperties[$attrname] = $fielddesc['name'];
                }
            }
        }

        if ( !array_key_exists( $name, $this->properties ) )
        {
            // eZ4 style: be tolerant! Shall we make it more strict?
            return null;
        }

        // In case of dynamic attributes, we need to use the dreaded closure.
        // We try to avoid this if possible
        if ( array_key_exists( $name, $this->staticproperties ) )
        {
            $field = $this->staticproperties[$name];
            $return = $this->object->$field;
        }
        else
        {
            $return = $this->object->attribute( $name );
            $obj = $this->object;
            $return = $this->getLegacyKernel()->runCallback(
                function () use ( $obj, $name )
                {
                    return $obj->attribute( $name );
                }
            );
        }

        return self::wrap( $return );
    }

    /**
     * Recursive wrapping of eZ4 "template objects" into ForwardAdapter objects
     */
    protected static wrap( $val )
    {
        if ( is_object( $val ) && is_callable( array( $val, 'attributes' ) ) && is_callable( array( $val, 'attribute' ) ) && is_callable( array( $val, 'hasAttribute' ) ) )
        {
            return new self( $val );
        }
        if ( is_array( $val ) )
        {
            foreach ( $val as $key => $value )
            {
                $val[$key] = self::wrap( $value );
            }
        }
        /// @todo should we disallow objects which do not implement the proper 3 methods?
        ///       We should check how they behave in ez4, most likely as "empty" objects...
        return $val;
    }

}

?>

Interesting, even if I still hardly see a valid use case.

• https://gist.github.com/gggeek/5110151#file-gistfile1-php-L33 : Use array_fill_keys() with true, this will make it possible to use isset() instead of array_key_exists()
• https://gist.github.com/gggeek/5110151#file-gistfile1-php-L35 : Maybe just check if object is instanceof eZPersistentObject ?
• I'm really not a fan of the recursive wrap() method. High performance hit detected !