Add support for Multisite Language Switcher (#1604)

Author: MatzeKitt

.github/changelog/1604-from-description

@@ -0,0 +1,4 @@
+Significance: minor
+Type: fixed
+
+Add support for Multisite Language Switcher

integration/class-multisite-language-switcher.php

@@ -0,0 +1,49 @@
+<?php
+/**
+ * Multisite Language Switcher integration class file.
+ *
+ * @package Activitypub
+ */
+
+namespace Activitypub\Integration;
+
+use Activitypub\Collection\Outbox;
+
+/**
+ * Compatibility with the Multisite Language Switcher plugin.
+ *
+ * @see https://github.com/lloc/Multisite-Language-Switcher/
+ */
+class Multisite_Language_Switcher {
+	/**
+	 * Initialize the class, registering WordPress hooks.
+	 */
+	public static function init() {
+		\add_action( 'save_post', array( self::class, 'ignore_outbox_post' ), 9, 2 );
+		\add_action( 'save_post', array( self::class, 'unignore_outbox_post' ), 11, 2 );
+	}
+
+	/**
+	 * Short-circuit saving Multisite Language Switcher data for the Outbox post type.
+	 *
+	 * @param int     $post_id The post id.
+	 * @param WP_Post $post The post object.
+	 */
+	public static function ignore_outbox_post( $post_id, $post ) {
+		if ( Outbox::POST_TYPE === $post->post_type ) {
+			\add_action( 'msls_main_save', '__return_null' );
+		}
+	}
+
+	/**
+	 * Remove short-circuit for Multisite Language Switcher data.
+	 *
+	 * @param int     $post_id The post id.
+	 * @param WP_Post $post The post object.
+	 */
+	public static function unignore_outbox_post( $post_id, $post ) {
+		if ( Outbox::POST_TYPE === $post->post_type ) {
+			\remove_action( 'msls_main_save', '__return_null' );
+		}
+	}
+}

integration/load.php

@@ -77,6 +77,17 @@ function plugin_init() {
 		Akismet::init();
 	}
 
+	/**
+	 * Adds Multisite Language Switcher support.
+	 *
+	 * This class handles the compatibility with the Multisite Language Switcher plugin.
+	 *
+	 * @see https://wordpress.org/plugins/multisite-language-switcher/
+	 */
+	if ( \defined( 'MSLS_PLUGIN_VERSION' ) ) {
+		Multisite_Language_Switcher::init();
+	}
+
 	/**
 	 * Adds Seriously Simple Podcasting support.
 	 *