source: tags/6.5/src/wp-admin/includes/class-theme-upgrader.php

<?php
/**
 * Upgrade API: Theme_Upgrader class
 *
 * @package WordPress
 * @subpackage Upgrader
 * @since 4.6.0
 */

/**
 * Core class used for upgrading/installing themes.
 *
 * It is designed to upgrade/install themes from a local zip, remote zip URL,
 * or uploaded zip file.
 *
 * @since 2.8.0
 * @since 4.6.0 Moved to its own file from wp-admin/includes/class-wp-upgrader.php.
 *
 * @see WP_Upgrader
 */
class Theme_Upgrader extends WP_Upgrader {

        /**
         * Result of the theme upgrade offer.
         *
         * @since 2.8.0
         * @var array|WP_Error $result
         * @see WP_Upgrader::$result
         */
        public $result;

        /**
         * Whether multiple themes are being upgraded/installed in bulk.
         *
         * @since 2.9.0
         * @var bool $bulk
         */
        public $bulk = false;

        /**
         * New theme info.
         *
         * @since 5.5.0
         * @var array $new_theme_data
         *
         * @see check_package()
         */
        public $new_theme_data = array();

        /**
         * Initializes the upgrade strings.
         *
         * @since 2.8.0
         */
        public function upgrade_strings() {
                $this->strings['up_to_date'] = __( 'The theme is at the latest version.' );
                $this->strings['no_package'] = __( 'Update package not available.' );
                /* translators: %s: Package URL. */
                $this->strings['downloading_package'] = sprintf( __( 'Downloading update from %s&#8230;' ), '<span class="code pre">%s</span>' );
                $this->strings['unpack_package']      = __( 'Unpacking the update&#8230;' );
                $this->strings['remove_old']          = __( 'Removing the old version of the theme&#8230;' );
                $this->strings['remove_old_failed']   = __( 'Could not remove the old theme.' );
                $this->strings['process_failed']      = __( 'Theme update failed.' );
                $this->strings['process_success']     = __( 'Theme updated successfully.' );
        }

        /**
         * Initializes the installation strings.
         *
         * @since 2.8.0
         */
        public function install_strings() {
                $this->strings['no_package'] = __( 'Installation package not available.' );
                /* translators: %s: Package URL. */
                $this->strings['downloading_package'] = sprintf( __( 'Downloading installation package from %s&#8230;' ), '<span class="code pre">%s</span>' );
                $this->strings['unpack_package']      = __( 'Unpacking the package&#8230;' );
                $this->strings['installing_package']  = __( 'Installing the theme&#8230;' );
                $this->strings['remove_old']          = __( 'Removing the old version of the theme&#8230;' );
                $this->strings['remove_old_failed']   = __( 'Could not remove the old theme.' );
                $this->strings['no_files']            = __( 'The theme contains no files.' );
                $this->strings['process_failed']      = __( 'Theme installation failed.' );
                $this->strings['process_success']     = __( 'Theme installed successfully.' );
                /* translators: 1: Theme name, 2: Theme version. */
                $this->strings['process_success_specific'] = __( 'Successfully installed the theme <strong>%1$s %2$s</strong>.' );
                $this->strings['parent_theme_search']      = __( 'This theme requires a parent theme. Checking if it is installed&#8230;' );
                /* translators: 1: Theme name, 2: Theme version. */
                $this->strings['parent_theme_prepare_install'] = __( 'Preparing to install <strong>%1$s %2$s</strong>&#8230;' );
                /* translators: 1: Theme name, 2: Theme version. */
                $this->strings['parent_theme_currently_installed'] = __( 'The parent theme, <strong>%1$s %2$s</strong>, is currently installed.' );
                /* translators: 1: Theme name, 2: Theme version. */
                $this->strings['parent_theme_install_success'] = __( 'Successfully installed the parent theme, <strong>%1$s %2$s</strong>.' );
                /* translators: %s: Theme name. */
                $this->strings['parent_theme_not_found'] = sprintf( __( '<strong>The parent theme could not be found.</strong> You will need to install the parent theme, %s, before you can use this child theme.' ), '<strong>%s</strong>' );
                /* translators: %s: Theme error. */
                $this->strings['current_theme_has_errors'] = __( 'The active theme has the following error: "%s".' );

                if ( ! empty( $this->skin->overwrite ) ) {
                        if ( 'update-theme' === $this->skin->overwrite ) {
                                $this->strings['installing_package'] = __( 'Updating the theme&#8230;' );
                                $this->strings['process_failed']     = __( 'Theme update failed.' );
                                $this->strings['process_success']    = __( 'Theme updated successfully.' );
                        }

                        if ( 'downgrade-theme' === $this->skin->overwrite ) {
                                $this->strings['installing_package'] = __( 'Downgrading the theme&#8230;' );
                                $this->strings['process_failed']     = __( 'Theme downgrade failed.' );
                                $this->strings['process_success']    = __( 'Theme downgraded successfully.' );
                        }
                }
        }

        /**
         * Checks if a child theme is being installed and its parent also needs to be installed.
         *
         * Hooked to the {@see 'upgrader_post_install'} filter by Theme_Upgrader::install().
         *
         * @since 3.4.0
         *
         * @param bool  $install_result
         * @param array $hook_extra
         * @param array $child_result
         * @return bool
         */
        public function check_parent_theme_filter( $install_result, $hook_extra, $child_result ) {
                // Check to see if we need to install a parent theme.
                $theme_info = $this->theme_info();

                if ( ! $theme_info->parent() ) {
                        return $install_result;
                }

                $this->skin->feedback( 'parent_theme_search' );

                if ( ! $theme_info->parent()->errors() ) {
                        $this->skin->feedback( 'parent_theme_currently_installed', $theme_info->parent()->display( 'Name' ), $theme_info->parent()->display( 'Version' ) );
                        // We already have the theme, fall through.
                        return $install_result;
                }

                // We don't have the parent theme, let's install it.
                $api = themes_api(
                        'theme_information',
                        array(
                                'slug'   => $theme_info->get( 'Template' ),
                                'fields' => array(
                                        'sections' => false,
                                        'tags'     => false,
                                ),
                        )
                ); // Save on a bit of bandwidth.

                if ( ! $api || is_wp_error( $api ) ) {
                        $this->skin->feedback( 'parent_theme_not_found', $theme_info->get( 'Template' ) );
                        // Don't show activate or preview actions after installation.
                        add_filter( 'install_theme_complete_actions', array( $this, 'hide_activate_preview_actions' ) );
                        return $install_result;
                }

                // Backup required data we're going to override:
                $child_api             = $this->skin->api;
                $child_success_message = $this->strings['process_success'];

                // Override them.
                $this->skin->api = $api;

                $this->strings['process_success_specific'] = $this->strings['parent_theme_install_success'];

                $this->skin->feedback( 'parent_theme_prepare_install', $api->name, $api->version );

                add_filter( 'install_theme_complete_actions', '__return_false', 999 ); // Don't show any actions after installing the theme.

                // Install the parent theme.
                $parent_result = $this->run(
                        array(
                                'package'           => $api->download_link,
                                'destination'       => get_theme_root(),
                                'clear_destination' => false, // Do not overwrite files.
                                'clear_working'     => true,
                        )
                );

                if ( is_wp_error( $parent_result ) ) {
                        add_filter( 'install_theme_complete_actions', array( $this, 'hide_activate_preview_actions' ) );
                }

                // Start cleaning up after the parent's installation.
                remove_filter( 'install_theme_complete_actions', '__return_false', 999 );

                // Reset child's result and data.
                $this->result                     = $child_result;
                $this->skin->api                  = $child_api;
                $this->strings['process_success'] = $child_success_message;

                return $install_result;
        }

        /**
         * Don't display the activate and preview actions to the user.
         *
         * Hooked to the {@see 'install_theme_complete_actions'} filter by
         * Theme_Upgrader::check_parent_theme_filter() when installing
         * a child theme and installing the parent theme fails.
         *
         * @since 3.4.0
         *
         * @param array $actions Preview actions.
         * @return array
         */
        public function hide_activate_preview_actions( $actions ) {
                unset( $actions['activate'], $actions['preview'] );
                return $actions;
        }

        /**
         * Install a theme package.
         *
         * @since 2.8.0
         * @since 3.7.0 The `$args` parameter was added, making clearing the update cache optional.
         *
         * @param string $package The full local path or URI of the package.
         * @param array  $args {
         *     Optional. Other arguments for installing a theme package. Default empty array.
         *
         *     @type bool $clear_update_cache Whether to clear the updates cache if successful.
         *                                    Default true.
         * }
         *
         * @return bool|WP_Error True if the installation was successful, false or a WP_Error object otherwise.
         */
        public function install( $package, $args = array() ) {
                $defaults    = array(
                        'clear_update_cache' => true,
                        'overwrite_package'  => false, // Do not overwrite files.
                );
                $parsed_args = wp_parse_args( $args, $defaults );

                $this->init();
                $this->install_strings();

                add_filter( 'upgrader_source_selection', array( $this, 'check_package' ) );
                add_filter( 'upgrader_post_install', array( $this, 'check_parent_theme_filter' ), 10, 3 );

                if ( $parsed_args['clear_update_cache'] ) {
                        // Clear cache so wp_update_themes() knows about the new theme.
                        add_action( 'upgrader_process_complete', 'wp_clean_themes_cache', 9, 0 );
                }

                $this->run(
                        array(
                                'package'           => $package,
                                'destination'       => get_theme_root(),
                                'clear_destination' => $parsed_args['overwrite_package'],
                                'clear_working'     => true,
                                'hook_extra'        => array(
                                        'type'   => 'theme',
                                        'action' => 'install',
                                ),
                        )
                );

                remove_action( 'upgrader_process_complete', 'wp_clean_themes_cache', 9 );
                remove_filter( 'upgrader_source_selection', array( $this, 'check_package' ) );
                remove_filter( 'upgrader_post_install', array( $this, 'check_parent_theme_filter' ) );

                if ( ! $this->result || is_wp_error( $this->result ) ) {
                        return $this->result;
                }

                // Refresh the Theme Update information.
                wp_clean_themes_cache( $parsed_args['clear_update_cache'] );

                if ( $parsed_args['overwrite_package'] ) {
                        /** This action is documented in wp-admin/includes/class-plugin-upgrader.php */
                        do_action( 'upgrader_overwrote_package', $package, $this->new_theme_data, 'theme' );
                }

                return true;
        }

        /**
         * Upgrades a theme.
         *
         * @since 2.8.0
         * @since 3.7.0 The `$args` parameter was added, making clearing the update cache optional.
         *
         * @param string $theme The theme slug.
         * @param array  $args {
         *     Optional. Other arguments for upgrading a theme. Default empty array.
         *
         *     @type bool $clear_update_cache Whether to clear the update cache if successful.
         *                                    Default true.
         * }
         * @return bool|WP_Error True if the upgrade was successful, false or a WP_Error object otherwise.
         */
        public function upgrade( $theme, $args = array() ) {
                $defaults    = array(
                        'clear_update_cache' => true,
                );
                $parsed_args = wp_parse_args( $args, $defaults );

                $this->init();
                $this->upgrade_strings();

                // Is an update available?
                $current = get_site_transient( 'update_themes' );
                if ( ! isset( $current->response[ $theme ] ) ) {
                        $this->skin->before();
                        $this->skin->set_result( false );
                        $this->skin->error( 'up_to_date' );
                        $this->skin->after();
                        return false;
                }

                $r = $current->response[ $theme ];

                add_filter( 'upgrader_pre_install', array( $this, 'current_before' ), 10, 2 );
                add_filter( 'upgrader_post_install', array( $this, 'current_after' ), 10, 2 );
                add_filter( 'upgrader_clear_destination', array( $this, 'delete_old_theme' ), 10, 4 );
                if ( $parsed_args['clear_update_cache'] ) {
                        // Clear cache so wp_update_themes() knows about the new theme.
                        add_action( 'upgrader_process_complete', 'wp_clean_themes_cache', 9, 0 );
                }

                $this->run(
                        array(
                                'package'           => $r['package'],
                                'destination'       => get_theme_root( $theme ),
                                'clear_destination' => true,
                                'clear_working'     => true,
                                'hook_extra'        => array(
                                        'theme'       => $theme,
                                        'type'        => 'theme',
                                        'action'      => 'update',
                                        'temp_backup' => array(
                                                'slug' => $theme,
                                                'src'  => get_theme_root( $theme ),
                                                'dir'  => 'themes',
                                        ),
                                ),
                        )
                );

                remove_action( 'upgrader_process_complete', 'wp_clean_themes_cache', 9 );
                remove_filter( 'upgrader_pre_install', array( $this, 'current_before' ) );
                remove_filter( 'upgrader_post_install', array( $this, 'current_after' ) );
                remove_filter( 'upgrader_clear_destination', array( $this, 'delete_old_theme' ) );

                if ( ! $this->result || is_wp_error( $this->result ) ) {
                        return $this->result;
                }

                wp_clean_themes_cache( $parsed_args['clear_update_cache'] );

                /*
                 * Ensure any future auto-update failures trigger a failure email by removing
                 * the last failure notification from the list when themes update successfully.
                 */
                $past_failure_emails = get_option( 'auto_plugin_theme_update_emails', array() );

                if ( isset( $past_failure_emails[ $theme ] ) ) {
                        unset( $past_failure_emails[ $theme ] );
                        update_option( 'auto_plugin_theme_update_emails', $past_failure_emails );
                }

                return true;
        }

        /**
         * Upgrades several themes at once.
         *
         * @since 3.0.0
         * @since 3.7.0 The `$args` parameter was added, making clearing the update cache optional.
         *
         * @global string $wp_version The WordPress version string.
         *
         * @param string[] $themes Array of the theme slugs.
         * @param array    $args {
         *     Optional. Other arguments for upgrading several themes at once. Default empty array.
         *
         *     @type bool $clear_update_cache Whether to clear the update cache if successful.
         *                                    Default true.
         * }
         * @return array[]|false An array of results, or false if unable to connect to the filesystem.
         */
        public function bulk_upgrade( $themes, $args = array() ) {
                global $wp_version;

                $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_themes' );

                add_filter( 'upgrader_pre_install', array( $this, 'current_before' ), 10, 2 );
                add_filter( 'upgrader_post_install', array( $this, 'current_after' ), 10, 2 );
                add_filter( 'upgrader_clear_destination', array( $this, 'delete_old_theme' ), 10, 4 );

                $this->skin->header();

                // Connect to the filesystem first.
                $res = $this->fs_connect( array( WP_CONTENT_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 themes specified, OR
                 * - a theme with an update available is currently in use.
                 * @todo For multisite, maintenance mode should only kick in for individual sites if at all possible.
                 */
                $maintenance = ( is_multisite() && ! empty( $themes ) );
                foreach ( $themes as $theme ) {
                        $maintenance = $maintenance || get_stylesheet() === $theme || get_template() === $theme;
                }
                if ( $maintenance ) {
                        $this->maintenance_mode( true );
                }

                $results = array();

                $this->update_count   = count( $themes );
                $this->update_current = 0;
                foreach ( $themes as $theme ) {
                        ++$this->update_current;

                        $this->skin->theme_info = $this->theme_info( $theme );

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

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

                        if ( isset( $r['requires'] ) && ! is_wp_version_compatible( $r['requires'] ) ) {
                                $result = new WP_Error(
                                        'incompatible_wp_required_version',
                                        sprintf(
                                                /* translators: 1: Current WordPress version, 2: WordPress version required by the new theme version. */
                                                __( 'Your WordPress version is %1$s, however the new theme version requires %2$s.' ),
                                                $wp_version,
                                                $r['requires']
                                        )
                                );

                                $this->skin->before( $result );
                                $this->skin->error( $result );
                                $this->skin->after();
                        } elseif ( isset( $r['requires_php'] ) && ! is_php_version_compatible( $r['requires_php'] ) ) {
                                $result = new WP_Error(
                                        'incompatible_php_required_version',
                                        sprintf(
                                                /* translators: 1: Current PHP version, 2: PHP version required by the new theme version. */
                                                __( 'The PHP version on your server is %1$s, however the new theme version requires %2$s.' ),
                                                PHP_VERSION,
                                                $r['requires_php']
                                        )
                                );

                                $this->skin->before( $result );
                                $this->skin->error( $result );
                                $this->skin->after();
                        } else {
                                add_filter( 'upgrader_source_selection', array( $this, 'check_package' ) );
                                $result = $this->run(
                                        array(
                                                'package'           => $r['package'],
                                                'destination'       => get_theme_root( $theme ),
                                                'clear_destination' => true,
                                                'clear_working'     => true,
                                                'is_multi'          => true,
                                                'hook_extra'        => array(
                                                        'theme'       => $theme,
                                                        'temp_backup' => array(
                                                                'slug' => $theme,
                                                                'src'  => get_theme_root( $theme ),
                                                                'dir'  => 'themes',
                                                        ),
                                                ),
                                        )
                                );
                                remove_filter( 'upgrader_source_selection', array( $this, 'check_package' ) );
                        }

                        $results[ $theme ] = $result;

                        // Prevent credentials auth screen from displaying multiple times.
                        if ( false === $result ) {
                                break;
                        }
                } // End foreach $themes.

                $this->maintenance_mode( false );

                // Refresh the Theme Update information.
                wp_clean_themes_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'   => 'theme',
                                'bulk'   => true,
                                'themes' => $themes,
                        )
                );

                $this->skin->bulk_footer();

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

                // Cleanup our hooks, in case something else does an upgrade on this connection.
                remove_filter( 'upgrader_pre_install', array( $this, 'current_before' ) );
                remove_filter( 'upgrader_post_install', array( $this, 'current_after' ) );
                remove_filter( 'upgrader_clear_destination', array( $this, 'delete_old_theme' ) );

                /*
                 * Ensure any future auto-update failures trigger a failure email by removing
                 * the last failure notification from the list when themes update successfully.
                 */
                $past_failure_emails = get_option( 'auto_plugin_theme_update_emails', array() );

                foreach ( $results as $theme => $result ) {
                        // Maintain last failure notification when themes failed to update manually.
                        if ( ! $result || is_wp_error( $result ) || ! isset( $past_failure_emails[ $theme ] ) ) {
                                continue;
                        }

                        unset( $past_failure_emails[ $theme ] );
                }

                update_option( 'auto_plugin_theme_update_emails', $past_failure_emails );

                return $results;
        }

        /**
         * Checks that the package source contains a valid theme.
         *
         * Hooked to the {@see 'upgrader_source_selection'} filter by Theme_Upgrader::install().
         *
         * @since 3.3.0
         *
         * @global WP_Filesystem_Base $wp_filesystem WordPress filesystem subclass.
         * @global string             $wp_version    The WordPress version string.
         *
         * @param string $source The path to the downloaded package source.
         * @return string|WP_Error The source as passed, or a WP_Error object on failure.
         */
        public function check_package( $source ) {
                global $wp_filesystem, $wp_version;

                $this->new_theme_data = array();

                if ( is_wp_error( $source ) ) {
                        return $source;
                }

                // Check that the folder contains a valid theme.
                $working_directory = str_replace( $wp_filesystem->wp_content_dir(), trailingslashit( WP_CONTENT_DIR ), $source );
                if ( ! is_dir( $working_directory ) ) { // Confidence check, if the above fails, let's not prevent installation.
                        return $source;
                }

                // A proper archive should have a style.css file in the single subdirectory.
                if ( ! file_exists( $working_directory . 'style.css' ) ) {
                        return new WP_Error(
                                'incompatible_archive_theme_no_style',
                                $this->strings['incompatible_archive'],
                                sprintf(
                                        /* translators: %s: style.css */
                                        __( 'The theme is missing the %s stylesheet.' ),
                                        '<code>style.css</code>'
                                )
                        );
                }

                // All these headers are needed on Theme_Installer_Skin::do_overwrite().
                $info = get_file_data(
                        $working_directory . 'style.css',
                        array(
                                'Name'        => 'Theme Name',
                                'Version'     => 'Version',
                                'Author'      => 'Author',
                                'Template'    => 'Template',
                                'RequiresWP'  => 'Requires at least',
                                'RequiresPHP' => 'Requires PHP',
                        )
                );

                if ( empty( $info['Name'] ) ) {
                        return new WP_Error(
                                'incompatible_archive_theme_no_name',
                                $this->strings['incompatible_archive'],
                                sprintf(
                                        /* translators: %s: style.css */
                                        __( 'The %s stylesheet does not contain a valid theme header.' ),
                                        '<code>style.css</code>'
                                )
                        );
                }

                /*
                 * Parent themes must contain an index file:
                 * - classic themes require /index.php
                 * - block themes require /templates/index.html or block-templates/index.html (deprecated 5.9.0).
                 */
                if (
                        empty( $info['Template'] ) &&
                        ! file_exists( $working_directory . 'index.php' ) &&
                        ! file_exists( $working_directory . 'templates/index.html' ) &&
                        ! file_exists( $working_directory . 'block-templates/index.html' )
                ) {
                        return new WP_Error(
                                'incompatible_archive_theme_no_index',
                                $this->strings['incompatible_archive'],
                                sprintf(
                                        /* translators: 1: templates/index.html, 2: index.php, 3: Documentation URL, 4: Template, 5: style.css */
                                        __( 'Template is missing. Standalone themes need to have a %1$s or %2$s template file. <a href="%3$s">Child themes</a> need to have a %4$s header in the %5$s stylesheet.' ),
                                        '<code>templates/index.html</code>',
                                        '<code>index.php</code>',
                                        __( 'https://developer.wordpress.org/themes/advanced-topics/child-themes/' ),
                                        '<code>Template</code>',
                                        '<code>style.css</code>'
                                )
                        );
                }

                $requires_php = isset( $info['RequiresPHP'] ) ? $info['RequiresPHP'] : null;
                $requires_wp  = isset( $info['RequiresWP'] ) ? $info['RequiresWP'] : null;

                if ( ! is_php_version_compatible( $requires_php ) ) {
                        $error = sprintf(
                                /* translators: 1: Current PHP version, 2: Version required by the uploaded theme. */
                                __( 'The PHP version on your server is %1$s, however the uploaded theme requires %2$s.' ),
                                PHP_VERSION,
                                $requires_php
                        );

                        return new WP_Error( 'incompatible_php_required_version', $this->strings['incompatible_archive'], $error );
                }
                if ( ! is_wp_version_compatible( $requires_wp ) ) {
                        $error = sprintf(
                                /* translators: 1: Current WordPress version, 2: Version required by the uploaded theme. */
                                __( 'Your WordPress version is %1$s, however the uploaded theme requires %2$s.' ),
                                $wp_version,
                                $requires_wp
                        );

                        return new WP_Error( 'incompatible_wp_required_version', $this->strings['incompatible_archive'], $error );
                }

                $this->new_theme_data = $info;

                return $source;
        }

        /**
         * Turns on maintenance mode before attempting to upgrade the active theme.
         *
         * Hooked to the {@see 'upgrader_pre_install'} filter by Theme_Upgrader::upgrade() and
         * Theme_Upgrader::bulk_upgrade().
         *
         * @since 2.8.0
         *
         * @param bool|WP_Error $response The installation response before the installation has started.
         * @param array         $theme    Theme arguments.
         * @return bool|WP_Error The original `$response` parameter or WP_Error.
         */
        public function current_before( $response, $theme ) {
                if ( is_wp_error( $response ) ) {
                        return $response;
                }

                $theme = isset( $theme['theme'] ) ? $theme['theme'] : '';

                // Only run if active theme.
                if ( get_stylesheet() !== $theme ) {
                        return $response;
                }

                // Change to maintenance mode. Bulk edit handles this separately.
                if ( ! $this->bulk ) {
                        $this->maintenance_mode( true );
                }

                return $response;
        }

        /**
         * Turns off maintenance mode after upgrading the active theme.
         *
         * Hooked to the {@see 'upgrader_post_install'} filter by Theme_Upgrader::upgrade()
         * and Theme_Upgrader::bulk_upgrade().
         *
         * @since 2.8.0
         *
         * @param bool|WP_Error $response The installation response after the installation has finished.
         * @param array         $theme    Theme arguments.
         * @return bool|WP_Error The original `$response` parameter or WP_Error.
         */
        public function current_after( $response, $theme ) {
                if ( is_wp_error( $response ) ) {
                        return $response;
                }

                $theme = isset( $theme['theme'] ) ? $theme['theme'] : '';

                // Only run if active theme.
                if ( get_stylesheet() !== $theme ) {
                        return $response;
                }

                // Ensure stylesheet name hasn't changed after the upgrade:
                if ( get_stylesheet() === $theme && $theme !== $this->result['destination_name'] ) {
                        wp_clean_themes_cache();
                        $stylesheet = $this->result['destination_name'];
                        switch_theme( $stylesheet );
                }

                // Time to remove maintenance mode. Bulk edit handles this separately.
                if ( ! $this->bulk ) {
                        $this->maintenance_mode( false );
                }
                return $response;
        }

        /**
         * Deletes the old theme during an upgrade.
         *
         * Hooked to the {@see 'upgrader_clear_destination'} filter by Theme_Upgrader::upgrade()
         * and Theme_Upgrader::bulk_upgrade().
         *
         * @since 2.8.0
         *
         * @global WP_Filesystem_Base $wp_filesystem Subclass
         *
         * @param bool   $removed
         * @param string $local_destination
         * @param string $remote_destination
         * @param array  $theme
         * @return bool
         */
        public function delete_old_theme( $removed, $local_destination, $remote_destination, $theme ) {
                global $wp_filesystem;

                if ( is_wp_error( $removed ) ) {
                        return $removed; // Pass errors through.
                }

                if ( ! isset( $theme['theme'] ) ) {
                        return $removed;
                }

                $theme      = $theme['theme'];
                $themes_dir = trailingslashit( $wp_filesystem->wp_themes_dir( $theme ) );
                if ( $wp_filesystem->exists( $themes_dir . $theme ) ) {
                        if ( ! $wp_filesystem->delete( $themes_dir . $theme, true ) ) {
                                return false;
                        }
                }

                return true;
        }

        /**
         * Gets the WP_Theme object for a theme.
         *
         * @since 2.8.0
         * @since 3.0.0 The `$theme` argument was added.
         *
         * @param string $theme The directory name of the theme. This is optional, and if not supplied,
         *��                     the directory name from the last result will be used.
         * @return WP_Theme|false The theme's info object, or false `$theme` is not supplied
         *                        and the last result isn't set.
         */
        public function theme_info( $theme = null ) {
                if ( empty( $theme ) ) {
                        if ( ! empty( $this->result['destination_name'] ) ) {
                                $theme = $this->result['destination_name'];
                        } else {
                                return false;
                        }
                }

                $theme = wp_get_theme( $theme );
                $theme->cache_delete();

                return $theme;
        }
}