diff -r 490d5cc509ed -r cf61fcea0001 wp/wp-admin/includes/class-language-pack-upgrader.php
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/wp/wp-admin/includes/class-language-pack-upgrader.php	Mon Oct 14 17:39:30 2019 +0200
@@ -0,0 +1,370 @@
+<?php
+/**
+ * Upgrade API: Language_Pack_Upgrader class
+ *
+ * @package WordPress
+ * @subpackage Upgrader
+ * @since 4.6.0
+ */
+
+/**
+ * Core class used for updating/installing language packs (translations)
+ * for plugins, themes, and core.
+ *
+ * @since 3.7.0
+ * @since 4.6.0 Moved to its own file from wp-admin/includes/class-wp-upgrader.php.
+ *
+ * @see WP_Upgrader
+ */
+class Language_Pack_Upgrader extends WP_Upgrader {
+
+	/**
+	 * Result of the language pack upgrade.
+	 *
+	 * @since 3.7.0
+	 * @var array|WP_Error $result
+	 * @see WP_Upgrader::$result
+	 */
+	public $result;
+
+	/**
+	 * Whether a bulk upgrade/installation is being performed.
+	 *
+	 * @since 3.7.0
+	 * @var bool $bulk
+	 */
+	public $bulk = true;
+
+	/**
+	 * Asynchronously upgrades language packs after other upgrades have been made.
+	 *
+	 * Hooked to the {@see 'upgrader_process_complete'} action by default.
+	 *
+	 * @since 3.7.0
+	 * @static
+	 *
+	 * @param false|WP_Upgrader $upgrader Optional. WP_Upgrader instance or false. If `$upgrader` is
+	 *                                    a Language_Pack_Upgrader instance, the method will bail to
+	 *                                    avoid recursion. Otherwise unused. Default false.
+	 */
+	public static function async_upgrade( $upgrader = false ) {
+		// Avoid recursion.
+		if ( $upgrader && $upgrader instanceof Language_Pack_Upgrader ) {
+			return;
+		}
+
+		// Nothing to do?
+		$language_updates = wp_get_translation_updates();
+		if ( ! $language_updates ) {
+			return;
+		}
+
+		/*
+		 * Avoid messing with VCS installations, at least for now.
+		 * Noted: this is not the ideal way to accomplish this.
+		 */
+		$check_vcs = new WP_Automatic_Updater;
+		if ( $check_vcs->is_vcs_checkout( WP_CONTENT_DIR ) ) {
+			return;
+		}
+
+		foreach ( $language_updates as $key => $language_update ) {
+			$update = ! empty( $language_update->autoupdate );
+
+			/**
+			 * Filters whether to asynchronously update translation for core, a plugin, or a theme.
+			 *
+			 * @since 4.0.0
+			 *
+			 * @param bool   $update          Whether to update.
+			 * @param object $language_update The update offer.
+			 */
+			$update = apply_filters( 'async_update_translation', $update, $language_update );
+
+			if ( ! $update ) {
+				unset( $language_updates[ $key ] );
+			}
+		}
+
+		if ( empty( $language_updates ) ) {
+			return;
+		}
+
+		// Re-use the automatic upgrader skin if the parent upgrader is using it.
+		if ( $upgrader && $upgrader->skin instanceof Automatic_Upgrader_Skin ) {
+			$skin = $upgrader->skin;
+		} else {
+			$skin = new Language_Pack_Upgrader_Skin( array(
+				'skip_header_footer' => true,
+			) );
+		}
+
+		$lp_upgrader = new Language_Pack_Upgrader( $skin );
+		$lp_upgrader->bulk_upgrade( $language_updates );
+	}
+
+	/**
+	 * Initialize the upgrade strings.
+	 *
+	 * @since 3.7.0
+	 */
+	public function upgrade_strings() {
+		$this->strings['starting_upgrade'] = __( 'Some of your translations need updating. Sit tight for a few more seconds while we update them as well.' );
+		$this->strings['up_to_date'] = __( 'The translations are up to date.' );
+		$this->strings['no_package'] = __( 'Update package not available.' );
+		/* translators: %s: package URL */
+		$this->strings['downloading_package'] = sprintf( __( 'Downloading translation from %s&#8230;' ), '<span class="code">%s</span>' );
+		$this->strings['unpack_package'] = __( 'Unpacking the update&#8230;' );
+		$this->strings['process_failed'] = __( 'Translation update failed.' );
+		$this->strings['process_success'] = __( 'Translation updated successfully.' );
+	}
+
+	/**
+	 * Upgrade a language pack.
+	 *
+	 * @since 3.7.0
+	 *
+	 * @param string|false $update Optional. Whether an update offer is available. Default false.
+	 * @param array        $args   Optional. Other optional arguments, see
+	 *                             Language_Pack_Upgrader::bulk_upgrade(). Default empty array.
+	 * @return array|bool|WP_Error The result of the upgrade, or a WP_Error object instead.
+	 */
+	public function upgrade( $update = false, $args = array() ) {
+		if ( $update ) {
+			$update = array( $update );
+		}
+
+		$results = $this->bulk_upgrade( $update, $args );
+
+		if ( ! is_array( $results ) ) {
+			return $results;
+		}
+
+		return $results[0];
+	}
+
+	/**
+	 * Bulk upgrade language packs.
+	 *
+	 * @since 3.7.0
+	 *
+	 * @global WP_Filesystem_Base $wp_filesystem Subclass
+	 *
+	 * @param array $language_updates Optional. Language pack updates. Default empty array.
+	 * @param array $args {
+	 *     Optional. Other arguments for upgrading multiple language packs. Default empty array
+	 *
+	 *     @type bool $clear_update_cache Whether to clear the update cache when done.
+	 *                                    Default true.
+	 * }
+	 * @return array|bool|WP_Error Will return an array of results, or true if there are no updates,
+	 *                                   false or WP_Error for initial errors.
+	 */
+	public function bulk_upgrade( $language_updates = array(), $args = array() ) {
+		global $wp_filesystem;
+
+		$defaults = array(
+			'clear_update_cache' => true,
+		);
+		$parsed_args = wp_parse_args( $args, $defaults );
+
+		$this->init();
+		$this->upgrade_strings();
+
+		if ( ! $language_updates )
+			$language_updates = wp_get_translation_updates();
+
+		if ( empty( $language_updates ) ) {
+			$this->skin->header();
+			$this->skin->set_result( true );
+			$this->skin->feedback( 'up_to_date' );
+			$this->skin->bulk_footer();
+			$this->skin->footer();
+			return true;
+		}
+
+		if ( 'upgrader_process_complete' == current_filter() )
+			$this->skin->feedback( 'starting_upgrade' );
+
+		// Remove any existing upgrade filters from the plugin/theme upgraders #WP29425 & #WP29230
+		remove_all_filters( 'upgrader_pre_install' );
+		remove_all_filters( 'upgrader_clear_destination' );
+		remove_all_filters( 'upgrader_post_install' );
+		remove_all_filters( 'upgrader_source_selection' );
+
+		add_filter( 'upgrader_source_selection', array( $this, 'check_package' ), 10, 2 );
+
+		$this->skin->header();
+
+		// Connect to the Filesystem first.
+		$res = $this->fs_connect( array( WP_CONTENT_DIR, WP_LANG_DIR ) );
+		if ( ! $res ) {
+			$this->skin->footer();
+			return false;
+		}
+
+		$results = array();
+
+		$this->update_count = count( $language_updates );
+		$this->update_current = 0;
+
+		/*
+		 * The filesystem's mkdir() is not recursive. Make sure WP_LANG_DIR exists,
+		 * as we then may need to create a /plugins or /themes directory inside of it.
+		 */
+		$remote_destination = $wp_filesystem->find_folder( WP_LANG_DIR );
+		if ( ! $wp_filesystem->exists( $remote_destination ) )
+			if ( ! $wp_filesystem->mkdir( $remote_destination, FS_CHMOD_DIR ) )
+				return new WP_Error( 'mkdir_failed_lang_dir', $this->strings['mkdir_failed'], $remote_destination );
+
+		$language_updates_results = array();
+
+		foreach ( $language_updates as $language_update ) {
+
+			$this->skin->language_update = $language_update;
+
+			$destination = WP_LANG_DIR;
+			if ( 'plugin' == $language_update->type )
+				$destination .= '/plugins';
+			elseif ( 'theme' == $language_update->type )
+				$destination .= '/themes';
+
+			$this->update_current++;
+
+			$options = array(
+				'package' => $language_update->package,
+				'destination' => $destination,
+				'clear_destination' => false,
+				'abort_if_destination_exists' => false, // We expect the destination to exist.
+				'clear_working' => true,
+				'is_multi' => true,
+				'hook_extra' => array(
+					'language_update_type' => $language_update->type,
+					'language_update' => $language_update,
+				)
+			);
+
+			$result = $this->run( $options );
+
+			$results[] = $this->result;
+
+			// Prevent credentials auth screen from displaying multiple times.
+			if ( false === $result ) {
+				break;
+			}
+
+			$language_updates_results[] = array(
+				'language' => $language_update->language,
+				'type'     => $language_update->type,
+				'slug'     => isset( $language_update->slug ) ? $language_update->slug : 'default',
+				'version'  => $language_update->version,
+			);
+		}
+
+		// Remove upgrade hooks which are not required for translation updates.
+		remove_action( 'upgrader_process_complete', array( 'Language_Pack_Upgrader', 'async_upgrade' ), 20 );
+		remove_action( 'upgrader_process_complete', 'wp_version_check' );
+		remove_action( 'upgrader_process_complete', 'wp_update_plugins' );
+		remove_action( 'upgrader_process_complete', 'wp_update_themes' );
+
+		/** This action is documented in wp-admin/includes/class-wp-upgrader.php */
+		do_action( 'upgrader_process_complete', $this, array(
+			'action'       => 'update',
+			'type'         => 'translation',
+			'bulk'         => true,
+			'translations' => $language_updates_results
+		) );
+
+		// Re-add upgrade hooks.
+		add_action( 'upgrader_process_complete', array( 'Language_Pack_Upgrader', 'async_upgrade' ), 20 );
+		add_action( 'upgrader_process_complete', 'wp_version_check', 10, 0 );
+		add_action( 'upgrader_process_complete', 'wp_update_plugins', 10, 0 );
+		add_action( 'upgrader_process_complete', 'wp_update_themes', 10, 0 );
+
+		$this->skin->bulk_footer();
+
+		$this->skin->footer();
+
+		// Clean up our hooks, in case something else does an upgrade on this connection.
+		remove_filter( 'upgrader_source_selection', array( $this, 'check_package' ) );
+
+		if ( $parsed_args['clear_update_cache'] ) {
+			wp_clean_update_cache();
+		}
+
+		return $results;
+	}
+
+	/**
+	 * Check the package source to make sure there are .mo and .po files.
+	 *
+	 * Hooked to the {@see 'upgrader_source_selection'} filter by
+	 * Language_Pack_Upgrader::bulk_upgrade().
+	 *
+	 * @since 3.7.0
+	 *
+	 * @global WP_Filesystem_Base $wp_filesystem Subclass
+	 *
+	 * @param string|WP_Error $source
+	 * @param string          $remote_source
+	 */
+	public function check_package( $source, $remote_source ) {
+		global $wp_filesystem;
+
+		if ( is_wp_error( $source ) )
+			return $source;
+
+		// Check that the folder contains a valid language.
+		$files = $wp_filesystem->dirlist( $remote_source );
+
+		// Check to see if a .po and .mo exist in the folder.
+		$po = $mo = false;
+		foreach ( (array) $files as $file => $filedata ) {
+			if ( '.po' == substr( $file, -3 ) )
+				$po = true;
+			elseif ( '.mo' == substr( $file, -3 ) )
+				$mo = true;
+		}
+
+		if ( ! $mo || ! $po ) {
+			return new WP_Error( 'incompatible_archive_pomo', $this->strings['incompatible_archive'],
+				/* translators: 1: .po 2: .mo */
+				sprintf( __( 'The language pack is missing either the %1$s or %2$s files.' ),
+					'<code>.po</code>',
+					'<code>.mo</code>'
+				)
+			);
+		}
+
+		return $source;
+	}
+
+	/**
+	 * Get the name of an item being updated.
+	 *
+	 * @since 3.7.0
+	 *
+	 * @param object $update The data for an update.
+	 * @return string The name of the item being updated.
+	 */
+	public function get_name_for_update( $update ) {
+		switch ( $update->type ) {
+			case 'core':
+				return 'WordPress'; // Not translated
+
+			case 'theme':
+				$theme = wp_get_theme( $update->slug );
+				if ( $theme->exists() )
+					return $theme->Get( 'Name' );
+				break;
+			case 'plugin':
+				$plugin_data = get_plugins( '/' . $update->slug );
+				$plugin_data = reset( $plugin_data );
+				if ( $plugin_data )
+					return $plugin_data['Name'];
+				break;
+		}
+		return '';
+	}
+
+}