Merged in feature/from-pantheon (pull request #16)

code from pantheon

* code from pantheon

wp/wp-content/plugins/wordpress-seo/src/integrations/watchers/indexable-post-meta-watcher.php

@@ -0,0 +1,109 @@
+<?php
+
+namespace Yoast\WP\SEO\Integrations\Watchers;
+
+use WPSEO_Meta;
+use Yoast\WP\SEO\Conditionals\Migrations_Conditional;
+use Yoast\WP\SEO\Integrations\Integration_Interface;
+
+/**
+ * WordPress post meta watcher.
+ */
+class Indexable_Post_Meta_Watcher implements Integration_Interface {
+
+	/**
+	 * The post watcher.
+	 *
+	 * @var Indexable_Post_Watcher
+	 */
+	protected $post_watcher;
+
+	/**
+	 * An array of post IDs that need to be updated.
+	 *
+	 * @var array
+	 */
+	protected $post_ids_to_update = [];
+
+	/**
+	 * Returns the conditionals based on which this loadable should be active.
+	 *
+	 * @return array
+	 */
+	public static function get_conditionals() {
+		return [ Migrations_Conditional::class ];
+	}
+
+	/**
+	 * Indexable_Postmeta_Watcher constructor.
+	 *
+	 * @param Indexable_Post_Watcher $post_watcher The post watcher.
+	 */
+	public function __construct( Indexable_Post_Watcher $post_watcher ) {
+		$this->post_watcher = $post_watcher;
+	}
+
+	/**
+	 * Initializes the integration.
+	 *
+	 * This is the place to register hooks and filters.
+	 */
+	public function register_hooks() {
+		// Register all posts whose meta have changed.
+		\add_action( 'added_post_meta', [ $this, 'add_post_id' ], 10, 3 );
+		\add_action( 'updated_post_meta', [ $this, 'add_post_id' ], 10, 3 );
+		\add_action( 'deleted_post_meta', [ $this, 'add_post_id' ], 10, 3 );
+
+		// Remove posts that get saved as they are handled by the Indexable_Post_Watcher.
+		\add_action( 'wp_insert_post', [ $this, 'remove_post_id' ] );
+		\add_action( 'delete_post', [ $this, 'remove_post_id' ] );
+		\add_action( 'edit_attachment', [ $this, 'remove_post_id' ] );
+		\add_action( 'add_attachment', [ $this, 'remove_post_id' ] );
+		\add_action( 'delete_attachment', [ $this, 'remove_post_id' ] );
+
+		// Update indexables of all registered posts.
+		\register_shutdown_function( [ $this, 'update_indexables' ] );
+	}
+
+	/**
+	 * Adds a post id to the array of posts to update.
+	 *
+	 * @param int|string $meta_id  The meta ID.
+	 * @param int|string $post_id  The post ID.
+	 * @param string     $meta_key The meta key.
+	 *
+	 * @return void
+	 */
+	public function add_post_id( $meta_id, $post_id, $meta_key ) {
+		// Only register changes to our own meta.
+		if ( \strpos( $meta_key, WPSEO_Meta::$meta_prefix ) !== 0 ) {
+			return;
+		}
+
+		if ( ! \in_array( $post_id, $this->post_ids_to_update, true ) ) {
+			$this->post_ids_to_update[] = (int) $post_id;
+		}
+	}
+
+	/**
+	 * Removes a post id from the array of posts to update.
+	 *
+	 * @param int|string $post_id The post ID.
+	 *
+	 * @return void
+	 */
+	public function remove_post_id( $post_id ) {
+		$this->post_ids_to_update = \array_diff( $this->post_ids_to_update, [ (int) $post_id ] );
+	}
+
+	/**
+	 * Updates all indexables changed during the request.
+	 *
+	 * @return void
+	 */
+	public function update_indexables() {
+		foreach ( $this->post_ids_to_update as $post_id ) {
+			$this->post_watcher->build_indexable( $post_id );
+		}
+	}
+}