Plugin_Upgrader::bulk_upgrade( array $plugins, array $args = array() )

	public function bulk_upgrade( $plugins, $args = array() ) {

		$defaults = array(
			'clear_update_cache' => true,
		);
		$parsed_args = wp_parse_args( $args, $defaults );

		$this->init();
		$this->bulk = true;
		$this->upgrade_strings();

		$current = get_site_transient( 'update_plugins' );

		add_filter('upgrader_clear_destination', array($this, 'delete_old_plugin'), 10, 4);

		$this->skin->header();

		// Connect to the Filesystem first.
		$res = $this->fs_connect( array(WP_CONTENT_DIR, WP_PLUGIN_DIR) );
		if ( ! $res ) {
			$this->skin->footer();
			return false;
		}

		$this->skin->bulk_header();

		/*
		 * Only start maintenance mode if:
		 * - running Multisite and there are one or more plugins specified, OR
		 * - a plugin with an update available is currently active.
		 * @TODO: For multisite, maintenance mode should only kick in for individual sites if at all possible.
		 */
		$maintenance = ( is_multisite() && ! empty( $plugins ) );
		foreach ( $plugins as $plugin )
			$maintenance = $maintenance || ( is_plugin_active( $plugin ) && isset( $current->response[ $plugin] ) );
		if ( $maintenance )
			$this->maintenance_mode(true);

		$results = array();

		$this->update_count = count($plugins);
		$this->update_current = 0;
		foreach ( $plugins as $plugin ) {
			$this->update_current++;
			$this->skin->plugin_info = get_plugin_data( WP_PLUGIN_DIR . '/' . $plugin, false, true);

			if ( !isset( $current->response[ $plugin ] ) ) {
				$this->skin->set_result('up_to_date');
				$this->skin->before();
				$this->skin->feedback('up_to_date');
				$this->skin->after();
				$results[$plugin] = true;
				continue;
			}

			// Get the URL to the zip file.
			$r = $current->response[ $plugin ];

			$this->skin->plugin_active = is_plugin_active($plugin);

			$result = $this->run( array(
				'package' => $r->package,
				'destination' => WP_PLUGIN_DIR,
				'clear_destination' => true,
				'clear_working' => true,
				'is_multi' => true,
				'hook_extra' => array(
					'plugin' => $plugin
				)
			) );

			$results[$plugin] = $this->result;

			// Prevent credentials auth screen from displaying multiple times
			if ( false === $result )
				break;
		} //end foreach $plugins

		$this->maintenance_mode(false);

		// Force refresh of plugin update information.
		wp_clean_plugins_cache( $parsed_args['clear_update_cache'] );

		/** This action is documented in wp-admin/includes/class-wp-upgrader.php */
		do_action( 'upgrader_process_complete', $this, array(
			'action' => 'update',
			'type' => 'plugin',
			'bulk' => true,
			'plugins' => $plugins,
		) );

		$this->skin->bulk_footer();

		$this->skin->footer();

		// Cleanup our hooks, in case something else does a upgrade on this connection.
		remove_filter('upgrader_clear_destination', array($this, 'delete_old_plugin'));

		return $results;
	}