wikimedia/mediawiki-extensions-Wikibase

<?php

namespace Wikibase\Repo\ChangeOp;

use Wikibase\Repo\ChangeOp\Deserialization\ChangeOpDeserializationException;
use Wikimedia\Assert\Assert;

/**
 * Turns entity change request into ChangeOp objects based on change request deserialization
 * configured for the particular entity type.
 *
 * @license GPL-2.0-or-later
 */
class EntityChangeOpProvider {

    /**
     * @var callable[]
     */
    private $changeOpDeserializerInstantiators;

    /**
     * @var ChangeOpDeserializer[]
     */
    private $changeOpDeserializers = [];

    /**
     * @param callable[] $changeOpDeserializerInstantiators Associative array mapping entity types (strings)
     * to callbacks instantiating ChangeOpDeserializer objects.
     */
    public function __construct( array $changeOpDeserializerInstantiators ) {
        Assert::parameterElementType( 'callable', $changeOpDeserializerInstantiators, '$changeOpDeserializerInstantiators' );
        Assert::parameterElementType(
            'string',
            array_keys( $changeOpDeserializerInstantiators ),
            'array_keys( $changeOpDeserializerInstantiators )'
        );

        $this->changeOpDeserializerInstantiators = $changeOpDeserializerInstantiators;
    }

    /**
     * @param string $entityType
     * @param array $changeRequest Data of change to apply, @see @ref docs_topics_changeop-serializations for format specification
     *
     * @throws ChangeOpDeserializationException
     *
     * @return ChangeOp
     */
    public function newEntityChangeOp( $entityType, array $changeRequest ) {
        $deserializer = $this->getDeserializerForEntityType( $entityType );

        return $deserializer->createEntityChangeOp( $changeRequest );
    }

    /**
     * @param string $type
     *
     * @throws ChangeOpDeserializationException
     *
     * @return ChangeOpDeserializer
     */
    private function getDeserializerForEntityType( $type ) {
        if ( !isset( $this->changeOpDeserializers[$type] ) ) {
            $this->changeOpDeserializers[$type] = $this->newDeserializerForEntityType( $type );
        }

        return $this->changeOpDeserializers[$type];
    }

    /**
     * @param string $type
     *
     * @throws ChangeOpDeserializationException
     *
     * @return ChangeOpDeserializer
     */
    private function newDeserializerForEntityType( $type ) {
        if ( !array_key_exists( $type, $this->changeOpDeserializerInstantiators ) ) {
            throw new ChangeOpDeserializationException(
                'Could not process change request for entity of type: ' . $type,
                'no-change-request-deserializer'
            );
        }

        $deserializer = call_user_func( $this->changeOpDeserializerInstantiators[$type] );
        Assert::postcondition(
            $deserializer instanceof ChangeOpDeserializer,
            'changeop-deserializer-callback defined for entity type: ' . $type . ' does not instantiate ChangeOpDeserializer'
        );

        return $deserializer;
    }

}