Chris@0: <?php
Chris@0: 
Chris@0: namespace Drupal\Core\Template;
Chris@0: 
Chris@0: use Drupal\Component\Utility\Html;
Chris@0: 
Chris@0: /**
Chris@0:  * Defines the base class for an attribute type.
Chris@0:  *
Chris@0:  * @see \Drupal\Core\Template\Attribute
Chris@0:  */
Chris@0: abstract class AttributeValueBase {
Chris@0: 
Chris@0:   /**
Chris@0:    * Renders '$name=""' if $value is an empty string.
Chris@0:    *
Chris@0:    * @see \Drupal\Core\Template\AttributeValueBase::render()
Chris@0:    */
Chris@0:   const RENDER_EMPTY_ATTRIBUTE = TRUE;
Chris@0: 
Chris@0:   /**
Chris@0:    * The value itself.
Chris@0:    *
Chris@0:    * @var mixed
Chris@0:    */
Chris@0:   protected $value;
Chris@0: 
Chris@0:   /**
Chris@0:    * The name of the value.
Chris@0:    *
Chris@0:    * @var mixed
Chris@0:    */
Chris@0:   protected $name;
Chris@0: 
Chris@0:   /**
Chris@0:    * Constructs a \Drupal\Core\Template\AttributeValueBase object.
Chris@0:    */
Chris@0:   public function __construct($name, $value) {
Chris@0:     $this->name = $name;
Chris@0:     $this->value = $value;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Returns a string representation of the attribute.
Chris@0:    *
Chris@0:    * While __toString only returns the value in a string form, render()
Chris@0:    * contains the name of the attribute as well.
Chris@0:    *
Chris@0:    * @return string
Chris@0:    *   The string representation of the attribute.
Chris@0:    */
Chris@0:   public function render() {
Chris@0:     $value = (string) $this;
Chris@0:     if (isset($this->value) && static::RENDER_EMPTY_ATTRIBUTE || !empty($value)) {
Chris@0:       return Html::escape($this->name) . '="' . $value . '"';
Chris@0:     }
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Returns the raw value.
Chris@0:    */
Chris@0:   public function value() {
Chris@0:     return $this->value;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Implements the magic __toString() method.
Chris@0:    */
Chris@0:   abstract public function __toString();
Chris@0: 
Chris@0: }