DisplayPluginCollection.php

<?php

namespace Drupal\views;

use Drupal\Component\Plugin\Exception\PluginException;
use Drupal\Component\Plugin\PluginManagerInterface;
use Drupal\Core\Plugin\DefaultLazyPluginCollection;

/**
 * A class which wraps the displays of a view so you can lazy-initialize them.
 */
class DisplayPluginCollection extends DefaultLazyPluginCollection {
    
    /**
     * Stores a reference to the view which has this displays attached.
     *
     * @var \Drupal\views\ViewExecutable
     */
    protected $view;
    
    /**
     * {@inheritdoc}
     */
    protected $pluginKey = 'display_plugin';
    
    /**
     * Constructs a DisplayPluginCollection object.
     *
     * @param \Drupal\views\ViewExecutable $view
     *   The view which has this displays attached.
     * @param \Drupal\Component\Plugin\PluginManagerInterface $manager
     *   The manager to be used for instantiating plugins.
     */
    public function __construct(ViewExecutable $view, PluginManagerInterface $manager) {
        parent::__construct($manager, $view->storage
            ->get('display'));
        $this->view = $view;
        $this->initializePlugin('default');
    }
    
    /**
     * Destructs a DisplayPluginCollection object.
     */
    public function __destruct() {
        $this->clear();
    }
    
    /**
     * {@inheritdoc}
     *
     * @return \Drupal\views\Plugin\views\display\DisplayPluginBase
     */
    public function &get($instance_id) {
        return parent::get($instance_id);
    }
    
    /**
     * {@inheritdoc}
     */
    public function clear() {
        foreach (array_filter($this->pluginInstances) as $display) {
            $display->destroy();
        }
        parent::clear();
    }
    
    /**
     * {@inheritdoc}
     */
    protected function initializePlugin($display_id) {
        // Retrieve and initialize the new display handler with data.
        $display =& $this->view->storage
            ->getDisplay($display_id);
        try {
            $this->configurations[$display_id] = $display;
            parent::initializePlugin($display_id);
        } catch (PluginException $e) {
            $message = $e->getMessage();
            \Drupal::messenger()->addWarning(t('@message', [
                '@message' => $message,
            ]));
        }
        // If no plugin instance has been created, return NULL.
        if (empty($this->pluginInstances[$display_id])) {
            return NULL;
        }
        $this->pluginInstances[$display_id]
            ->initDisplay($this->view, $display);
        // If this is not the default display handler, let it know which is since
        // it may well use some data from the default.
        if ($display_id != 'default') {
            $this->pluginInstances[$display_id]->default_display = $this->pluginInstances['default'];
        }
    }
    
    /**
     * {@inheritdoc}
     */
    public function remove($instance_id) {
        $this->get($instance_id)
            ->remove();
        parent::remove($instance_id);
    }

}