WP_Upgrader::run( $options )

	public function run( $options ) {

		$defaults = array(
			'package' => '', // Please always pass this.
			'destination' => '', // And this
			'clear_destination' => false,
			'abort_if_destination_exists' => true, // Abort if the Destination directory exists, Pass clear_destination as false please
			'clear_working' => true,
			'is_multi' => false,
			'hook_extra' => array() // Pass any extra $hook_extra args here, this will be passed to any hooked filters.
		);

		$options = wp_parse_args( $options, $defaults );

		/**
		 * Filters the package options before running an update.
		 *
		 * See also {@see 'upgrader_process_complete'}.
		 *
		 * @since WP-4.3.0
		 *
		 * @param array $options {
		 *     Options used by the upgrader.
		 *
		 *     @type string $package                     Package for update.
		 *     @type string $destination                 Update location.
		 *     @type bool   $clear_destination           Clear the destination resource.
		 *     @type bool   $clear_working               Clear the working resource.
		 *     @type bool   $abort_if_destination_exists Abort if the Destination directory exists.
		 *     @type bool   $is_multi                    Whether the upgrader is running multiple times.
		 *     @type array  $hook_extra {
		 *         Extra hook arguments.
		 *
		 *         @type string $action               Type of action. Default 'update'.
		 *         @type string $type                 Type of update process. Accepts 'plugin', 'theme', or 'core'.
		 *         @type bool   $bulk                 Whether the update process is a bulk update. Default true.
		 *         @type string $plugin               The base plugin path from the plugins directory.
		 *         @type string $theme                The stylesheet or template name of the theme.
		 *         @type string $language_update_type The language pack update type. Accepts 'plugin', 'theme',
		 *                                            or 'core'.
		 *         @type object $language_update      The language pack update offer.
		 *     }
		 * }
		 */
		$options = apply_filters( 'upgrader_package_options', $options );

		if ( ! $options['is_multi'] ) { // call $this->header separately if running multiple times
			$this->skin->header();
		}

		// Connect to the Filesystem first.
		$res = $this->fs_connect( array( WP_CONTENT_DIR, $options['destination'] ) );
		// Mainly for non-connected filesystem.
		if ( ! $res ) {
			if ( ! $options['is_multi'] ) {
				$this->skin->footer();
			}
			return false;
		}

		$this->skin->before();

		if ( is_wp_error($res) ) {
			$this->skin->error($res);
			$this->skin->after();
			if ( ! $options['is_multi'] ) {
				$this->skin->footer();
			}
			return $res;
		}

		/*
		 * Download the package (Note, This just returns the filename
		 * of the file if the package is a local file)
		 */
		$download = $this->download_package( $options['package'] );
		if ( is_wp_error($download) ) {
			$this->skin->error($download);
			$this->skin->after();
			if ( ! $options['is_multi'] ) {
				$this->skin->footer();
			}
			return $download;
		}

		$delete_package = ( $download != $options['package'] ); // Do not delete a "local" file

		// Unzips the file into a temporary directory.
		$working_dir = $this->unpack_package( $download, $delete_package );
		if ( is_wp_error($working_dir) ) {
			$this->skin->error($working_dir);
			$this->skin->after();
			if ( ! $options['is_multi'] ) {
				$this->skin->footer();
			}
			return $working_dir;
		}

		// With the given options, this installs it to the destination directory.
		$result = $this->install_package( array(
			'source' => $working_dir,
			'destination' => $options['destination'],
			'clear_destination' => $options['clear_destination'],
			'abort_if_destination_exists' => $options['abort_if_destination_exists'],
			'clear_working' => $options['clear_working'],
			'hook_extra' => $options['hook_extra']
		) );

		$this->skin->set_result($result);
		if ( is_wp_error($result) ) {
			$this->skin->error($result);
			$this->skin->feedback('process_failed');
		} else {
			// Installation succeeded.
			$this->skin->feedback('process_success');
		}

		$this->skin->after();

		if ( ! $options['is_multi'] ) {

			/**
			 * Fires when the upgrader process is complete.
			 *
			 * See also {@see 'upgrader_package_options'}.
			 *
			 * @since WP-3.6.0
			 * @since WP-3.7.0 Added to WP_Upgrader::run().
			 * @since WP-4.6.0 `$translations` was added as a possible argument to `$hook_extra`.
			 *
			 * @param WP_Upgrader $this WP_Upgrader instance. In other contexts, $this, might be a
			 *                          Theme_Upgrader, Plugin_Upgrader, Core_Upgrade, or Language_Pack_Upgrader instance.
			 * @param array       $hook_extra {
			 *     Array of bulk item update data.
			 *
			 *     @type string $action       Type of action. Default 'update'.
			 *     @type string $type         Type of update process. Accepts 'plugin', 'theme', 'translation', or 'core'.
			 *     @type bool   $bulk         Whether the update process is a bulk update. Default true.
			 *     @type array  $plugins      Array of the basename paths of the plugins' main files.
			 *     @type array  $themes       The theme slugs.
			 *     @type array  $translations {
			 *         Array of translations update data.
			 *
			 *         @type string $language The locale the translation is for.
			 *         @type string $type     Type of translation. Accepts 'plugin', 'theme', or 'core'.
			 *         @type string $slug     Text domain the translation is for. The slug of a theme/plugin or
			 *                                'default' for core translations.
			 *         @type string $version  The version of a theme, plugin, or core.
			 *     }
			 * }
			 */
			do_action( 'upgrader_process_complete', $this, $options['hook_extra'] );

			$this->skin->footer();
		}

		return $result;
	}