ContextMapper.php

<?php

namespace Drupal\ctools;

use Drupal\Core\Entity\EntityRepositoryInterface;
use Drupal\Core\Plugin\Context\Context;
use Drupal\Core\Plugin\Context\ContextDefinition;
use Drupal\Core\Plugin\Context\EntityContextDefinition;
use Drupal\ctools\Context\EntityLazyLoadContext;

/**
 * Maps context configurations to context objects.
 */
class ContextMapper implements ContextMapperInterface {
    
    /**
     * The entity repository.
     *
     * @var \Drupal\Core\Entity\EntityRepositoryInterface
     */
    protected $entityRepository;
    
    /**
     * Constructs a new ContextMapper.
     *
     * @param \Drupal\Core\Entity\EntityRepositoryInterface $entity_repository
     *   The entity repository.
     */
    public function __construct(EntityRepositoryInterface $entity_repository) {
        $this->entityRepository = $entity_repository;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getContextValues(array $context_configurations) {
        $contexts = [];
        foreach ($context_configurations as $name => $context_configuration) {
            if (strpos($context_configuration['type'], 'entity:') === 0) {
                $context_definition = new EntityContextDefinition($context_configuration['type'], $context_configuration['label'], TRUE, FALSE, $context_configuration['description']);
                $context = new EntityLazyLoadContext($context_definition, $this->entityRepository, $context_configuration['value']);
            }
            else {
                $context_definition = new ContextDefinition($context_configuration['type'], $context_configuration['label'], TRUE, FALSE, $context_configuration['description']);
                $context = new Context($context_definition, $context_configuration['value']);
            }
            $contexts[$name] = $context;
        }
        return $contexts;
    }

}