TypedDataRelationship.php

<?php

namespace Drupal\ctools\Plugin\Relationship;

use Drupal\Core\Field\FieldItemInterface;
use Drupal\Core\Plugin\Context\Context;
use Drupal\Core\Plugin\Context\ContextDefinition;
use Drupal\Core\Plugin\Context\ContextInterface;
use Drupal\Core\Plugin\Context\EntityContextDefinition;
use Drupal\Core\TypedData\DataReferenceInterface;
use Drupal\Core\TypedData\ListInterface;
use Drupal\ctools\Plugin\RelationshipBase;

/**
 * @Relationship(
 *   id = "typed_data_relationship",
 *   deriver = "\Drupal\ctools\Plugin\Deriver\TypedDataRelationshipDeriver"
 * )
 */
class TypedDataRelationship extends RelationshipBase {
    
    /**
     * {@inheritdoc}
     */
    public function getRelationship() {
        $plugin_definition = $this->getPluginDefinition();
        $data_type = $plugin_definition['data_type'];
        if (strpos($data_type, 'entity:') === 0) {
            $context_definition = new EntityContextDefinition($data_type, $plugin_definition['label']);
        }
        else {
            $context_definition = new ContextDefinition($data_type, $plugin_definition['label']);
        }
        $context_value = NULL;
        // If the 'base' context has a value, then get the property value to put on
        // the context (otherwise, mapping hasn't occurred yet and we just want to
        // return the context with the right definition and no value).
        if ($this->getContext('base')
            ->hasContextValue()) {
            $data = $this->getData($this->getContext('base'));
            $property = $this->getMainPropertyName($data);
            $context_value = $data->get($property)
                ->getValue();
        }
        $context_definition->setDefaultValue($context_value);
        return new Context($context_definition, $context_value);
    }
    
    /**
     *
     */
    public function getName() {
        return $this->getPluginDefinition()['property_name'];
    }
    
    /**
     *
     */
    protected function getData(ContextInterface $context) {
        
        /** @var \Drupal\Core\TypedData\ComplexDataInterface $base */
        $base = $context->getContextValue();
        $name = $this->getPluginDefinition()['property_name'];
        $data = $base->get($name);
        // @todo add configuration to get N instead of first.
        if ($data instanceof ListInterface) {
            $data = $data->first();
        }
        if ($data instanceof DataReferenceInterface) {
            $data = $data->getTarget();
        }
        return $data;
    }
    
    /**
     *
     */
    protected function getMainPropertyName(FieldItemInterface $data) {
        return $data->getFieldDefinition()
            ->getFieldStorageDefinition()
            ->getMainPropertyName();
    }
    
    /**
     *
     */
    public function getRelationshipValue() {
        $property = $this->getMainPropertyName();
        
        /** @var \Drupal\Core\TypedData\ComplexDataInterface $data */
        $data = $this->getRelationship()
            ->getContextData();
        $data->get($property)
            ->getValue();
    }

}