Add foundational Context stuff from Rules.

<?php

namespace Drupal\typed_data\Context;

use Doctrine\Common\Annotations\SimpleAnnotationReader;

use \Drupal\Core\Plugin\Discovery\AnnotatedClassDiscovery as CoreAnnotatedClassDiscovery;

/**

 * Extends the annotation class discovery for usage with Typed data context.

 *

 * We modify the annotations classes for ContextDefinition and for Condition.

 * This class makes sure that our plugin managers apply these.

 */

class AnnotatedClassDiscovery extends CoreAnnotatedClassDiscovery {

  /**

   * {@inheritdoc}

   */

  protected function getAnnotationReader() {

    if (!isset($this->annotationReader)) {

      // Do not call out the parent, but re-configure the simple annotation

      // reader on our own, so we can control the order of namespaces.

      $this->annotationReader = new SimpleAnnotationReader();

      // Make sure to add our namespace first, so our ContextDefinition and

      // Condition annotations gets picked.

      $this->annotationReader->addNamespace('Drupal\typed_data\Context\Annotation');

      // Add the namespaces from the main plugin annotation, like @EntityType.

      $namespace = substr($this->pluginDefinitionAnnotationName, 0, strrpos($this->pluginDefinitionAnnotationName, '\\'));

      $this->annotationReader->addNamespace($namespace);

      // Add general core annotations like @Translation.

      $this->annotationReader->addNamespace('Drupal\Core\Annotation');

    }

    return $this->annotationReader;

  }

}

<?php

namespace Drupal\typed_data\Context\Annotation;

use Drupal\Core\Annotation\ContextDefinition as CoreContextDefinition;

use Drupal\Core\Annotation\Translation;

use Drupal\typed_data\Context\ContextDefinition as TypedDataContextDefinition;

/**

 * Extends the core context definition annotation object for Typed data.

 *

 * Ensures context definitions use

 * \Drupal\typed_data\Context\ContextDefinitionInterface.

 *

 * @Annotation

 *

 * @ingroup plugin_context

 */

class ContextDefinition extends CoreContextDefinition {

  /**

   * The ContextDefinitionInterface object.

   *

   * @var \Drupal\typed_data\Context\ContextDefinitionInterface

   */

  protected $definition;

  /**

   * {@inheritdoc}

   */

  public function __construct(array $values) {

    // Filter out any @Translation annotation objects.

    foreach ($values as $key => $value) {

      if ($value instanceof Translation) {

        $values[$key] = $value->get();

      }

    }

    $this->definition = TypedDataContextDefinition::createFromArray($values);

  }

  /**

   * Returns the value of an annotation.

   *

   * @return \Drupal\typed_data\Context\ContextDefinitionInterface

   *   Return the Typed data version of the ContextDefinitionInterface.

   */

  public function get() {

    return $this->definition;

  }

}

<?php

namespace Drupal\typed_data\Context;

use \Drupal\Core\Plugin\Context\ContextDefinition as ContextDefinitionCore;

use \Drupal\Component\Plugin\Exception\ContextException;

/**

 * Extends the core context definition class with useful methods.

 */

class ContextDefinition extends ContextDefinitionCore implements ContextDefinitionInterface {

  /**

   * The mapping of config export keys to internal properties.

   *

   * @var array

   */

  protected static $nameMap = [

    'type' => 'dataType',

    'label' => 'label',

    'description' => 'description',

    'multiple' => 'isMultiple',

    'required' => 'isRequired',

    'default_value' => 'defaultValue',

    'constraints' => 'constraints',

    'allow_null' => 'allowNull',

    'assignment_restriction' => 'assignmentRestriction',

  ];

  /**

   * Whether the context value is allowed to be NULL or not.

   *

   * @var bool

   */

  protected $allowNull = FALSE;

  /**

   * The assignment restriction of this context.

   *

   * @var string|null

   *

   * @see \Drupal\typed_data\Context\ContextDefinitionInterface::getAssignmentRestriction()

   */

  protected $assignmentRestriction = NULL;

  /**

   * {@inheritdoc}

   */

  public function toArray() {

    $values = [];

    $defaults = get_class_vars(__CLASS__);

    foreach (static::$nameMap as $key => $property_name) {

      // Only export values for non-default properties.

      if ($this->$property_name !== $defaults[$property_name]) {

        $values[$key] = $this->$property_name;

      }

    }

    return $values;

  }

  /**

   * Creates a definition object from an exported array of values.

   *

   * @param array $values

   *   The array of values, as returned by toArray().

   *

   * @return static

   *   The created definition.

   *

   * @throws \Drupal\Component\Plugin\Exception\ContextException

   *   If the required classes are not implemented.

   */

  public static function createFromArray($values) {

    if (isset($values['class']) && !in_array(ContextDefinitionInterface::class, class_implements($values['class']))) {

      throw new ContextException('ContextDefinition class must implement ' . ContextDefinitionInterface::class . '.');

    }

    // Default to Typed data context definition class.

    $values['class'] = isset($values['class']) ? $values['class'] : ContextDefinition::class;

    if (!isset($values['value'])) {

      $values['value'] = 'any';

    }

    $definition = $values['class']::create($values['value']);

    foreach (array_intersect_key(static::$nameMap, $values) as $key => $name) {

      $definition->$name = $values[$key];

    }

    return $definition;

  }

  /**

   * {@inheritdoc}

   */

  public function isAllowedNull() {

    return $this->allowNull;

  }

  /**

   * {@inheritdoc}

   */

  public function setAllowNull($null_allowed) {

    $this->allowNull = $null_allowed;

    return $this;

  }

  /**

   * {@inheritdoc}

   */

  public function getAssignmentRestriction() {

    return $this->assignmentRestriction;

  }

  /**

   * {@inheritdoc}

   */

  public function setAssignmentRestriction($restriction) {

    $this->assignmentRestriction = $restriction;

    return $this;

  }

}

<?php

namespace Drupal\typed_data\Context;

use \Drupal\Core\Plugin\Context\ContextDefinitionInterface as CoreContextDefinitionInterfaceCore;

/**

 * Context definition information required by Typed data.

 *

 * The core interface is extended to add properties that are necessary for

 * Typed data.

 */

interface ContextDefinitionInterface extends CoreContextDefinitionInterfaceCore {

  /**

   * Constants for the context assignment restriction mode.

   *

   * @see ::getAssignmentRestriction()

   */

  const ASSIGNMENT_RESTRICTION_INPUT = 'input';

  const ASSIGNMENT_RESTRICTION_SELECTOR = 'selector';

  /**

   * Determines if the context value is allowed to be NULL.

   *

   * @return bool

   *   TRUE if NULL values are allowed, FALSE otherwise.

   */

  public function isAllowedNull();

  /**

   * Sets the "allow NULL value" behavior.

   *

   * @param bool $null_allowed

   *   TRUE if NULL values should be allowed, FALSE otherwise.

   *

   * @return $this

   */

  public function setAllowNull($null_allowed);

  /**

   * Determines if this context has an assignment restriction.

   *

   * @return string|null

   *   Either ASSIGNMENT_RESTRICTION_INPUT for contexts that are only allowed to

   *   be provided as input values, ASSIGNMENT_RESTRICTION_SELECTOR for contexts

   *   that must be provided as data selectors or NULL if there is no

   *   restriction for this context.

   */

  public function getAssignmentRestriction();

  /**

   * Sets the assignment restriction mode for this context.

   *

   * @param string|null $restriction

   *   Either ASSIGNMENT_RESTRICTION_INPUT for contexts that are only allowed to

   *   be provided as input values, ASSIGNMENT_RESTRICTION_SELECTOR for contexts

   *   that must be provided as data selectors or NULL if there is no

   *   restriction for this context.

   */

  public function setAssignmentRestriction($restriction);

  /**

   * Exports the definition as an array.

   *

   * @return array

   *   An array with values for all definition keys.

   */

  public function toArray();

}