WordPress/wp-admin/includes/update-core.php

<?php
/**
 * WordPress core upgrade functionality.
 *
 * @package WordPress
 * @subpackage Administration
 * @since 2.7.0
 */

/**
 * Stores files to be deleted.
 *
 * @since 2.7.0
 * @global array $_old_files
 * @var array
 * @name $_old_files
 */
global $_old_files;

$_old_files = array(
'wp-admin/bookmarklet.php',
'wp-admin/css/upload.css',
'wp-admin/images/box-bg-left.gif',
'wp-admin/images/box-bg-right.gif',
'wp-admin/images/box-bg.gif',
'wp-admin/images/box-butt-left.gif',
'wp-admin/images/box-butt-right.gif',
'wp-admin/images/box-butt.gif',
'wp-admin/images/box-head-left.gif',
'wp-admin/images/box-head-right.gif',
'wp-admin/images/box-head.gif',
'wp-admin/images/heading-bg.gif',
'wp-admin/images/login-bkg-bottom.gif',
'wp-admin/images/login-bkg-tile.gif',
'wp-admin/images/notice.gif',
'wp-admin/images/toggle.gif',
'wp-admin/includes/upload.php',
'wp-admin/js/dbx-admin-key.js',
'wp-admin/js/link-cat.js',
'wp-admin/profile-update.php',
'wp-admin/templates.php',
'wp-includes/js/dbx.js',
'wp-includes/js/fat.js',
'wp-includes/js/list-manipulation.js',
'wp-includes/js/jquery/jquery.dimensions.min.js',
'wp-includes/js/tinymce/langs/en.js',
'wp-includes/js/tinymce/plugins/autosave/editor_plugin_src.js',
'wp-includes/js/tinymce/plugins/autosave/langs',
'wp-includes/js/tinymce/plugins/directionality/images',
'wp-includes/js/tinymce/plugins/directionality/langs',
'wp-includes/js/tinymce/plugins/inlinepopups/css',
'wp-includes/js/tinymce/plugins/inlinepopups/images',
'wp-includes/js/tinymce/plugins/inlinepopups/jscripts',
'wp-includes/js/tinymce/plugins/paste/images',
'wp-includes/js/tinymce/plugins/paste/jscripts',
'wp-includes/js/tinymce/plugins/paste/langs',
'wp-includes/js/tinymce/plugins/spellchecker/classes/HttpClient.class.php',
'wp-includes/js/tinymce/plugins/spellchecker/classes/TinyGoogleSpell.class.php',
'wp-includes/js/tinymce/plugins/spellchecker/classes/TinyPspell.class.php',
'wp-includes/js/tinymce/plugins/spellchecker/classes/TinyPspellShell.class.php',
'wp-includes/js/tinymce/plugins/spellchecker/css/spellchecker.css',
'wp-includes/js/tinymce/plugins/spellchecker/images',
'wp-includes/js/tinymce/plugins/spellchecker/langs',
'wp-includes/js/tinymce/plugins/spellchecker/tinyspell.php',
'wp-includes/js/tinymce/plugins/wordpress/images',
'wp-includes/js/tinymce/plugins/wordpress/langs',
'wp-includes/js/tinymce/plugins/wordpress/popups.css',
'wp-includes/js/tinymce/plugins/wordpress/wordpress.css',
'wp-includes/js/tinymce/plugins/wphelp',
'wp-includes/js/tinymce/themes/advanced/css',
'wp-includes/js/tinymce/themes/advanced/images',
'wp-includes/js/tinymce/themes/advanced/jscripts',
'wp-includes/js/tinymce/themes/advanced/langs',
'wp-includes/js/tinymce/tiny_mce_gzip.php',
'wp-includes/js/wp-ajax.js',
'wp-admin/admin-db.php',
'wp-admin/cat.js',
'wp-admin/categories.js',
'wp-admin/custom-fields.js',
'wp-admin/dbx-admin-key.js',
'wp-admin/edit-comments.js',
'wp-admin/install-rtl.css',
'wp-admin/install.css',
'wp-admin/upgrade-schema.php',
'wp-admin/upload-functions.php',
'wp-admin/upload-rtl.css',
'wp-admin/upload.css',
'wp-admin/upload.js',
'wp-admin/users.js',
'wp-admin/widgets-rtl.css',
'wp-admin/widgets.css',
'wp-admin/xfn.js',
'wp-includes/js/tinymce/license.html',
'wp-admin/cat-js.php',
'wp-admin/edit-form-ajax-cat.php',
'wp-admin/execute-pings.php',
'wp-admin/import/b2.php',
'wp-admin/inline-uploading.php',
'wp-admin/link-categories.php',
'wp-admin/list-manipulation.js',
'wp-admin/list-manipulation.php',
'wp-includes/comment-functions.php',
'wp-includes/feed-functions.php',
'wp-includes/functions-compat.php',
'wp-includes/functions-formatting.php',
'wp-includes/functions-post.php',
'wp-includes/js/dbx-key.js',
'wp-includes/js/tinymce/plugins/autosave/langs/cs.js',
'wp-includes/js/tinymce/plugins/autosave/langs/sv.js',
'wp-includes/js/tinymce/themes/advanced/editor_template_src.js',
'wp-includes/links.php',
'wp-includes/pluggable-functions.php',
'wp-includes/template-functions-author.php',
'wp-includes/template-functions-category.php',
'wp-includes/template-functions-general.php',
'wp-includes/template-functions-links.php',
'wp-includes/template-functions-post.php',
'wp-includes/wp-l10n.php',
'wp-admin/import-b2.php',
'wp-admin/import-blogger.php',
'wp-admin/import-greymatter.php',
'wp-admin/import-livejournal.php',
'wp-admin/import-mt.php',
'wp-admin/import-rss.php',
'wp-admin/import-textpattern.php',
'wp-admin/quicktags.js',
'wp-images/fade-butt.png',
'wp-images/get-firefox.png',
'wp-images/header-shadow.png',
'wp-images/smilies',
'wp-images/wp-small.png',
'wp-images/wpminilogo.png',
'wp.php',
'wp-content/themes/default/attachment.php',
'wp-content/themes/default/images/kubrickbg.jpg',
'wp-content/plugins/markdown.php',
'wp-content/plugins/textile1.php',
);

/**
 * Upgrade the core of WordPress.
 *
 * This will create a .maintenance file at the base of the WordPress directory
 * to ensure that people can not access the web site, when the files are being
 * copied to their locations.
 *
 * The files in the {@link $_old_files} list will be removed and the new files
 * copied from the zip file after the database is upgraded.
 *
 * The steps for the upgrader for after the new release is downloaded and
 * unzipped is:
 *   1. Test unzipped location for select files to ensure that unzipped worked.
 *   2. Create the .maintenance file in current WordPress base.
 *   3. Copy new WordPress directory over old WordPress files.
 *   4. Upgrade WordPress to new version.
 *   5. Delete new WordPress directory path.
 *   6. Delete .maintenance file.
 *   7. Remove old files.
 *   8. Delete 'update_core' option.
 *
 * There are several areas of failure. For instance if PHP times out before step
 * 6, then you will not be able to access any portion of your site. Also, since
 * the upgrade will not continue where it left off, you will not be able to
 * automatically remove old files and remove the 'update_core' option. This
 * isn't that bad.
 *
 * If the copy of the new WordPress over the old fails, then the worse is that
 * the new WordPress directory will remain.
 *
 * If it is assumed that every file will be copied over, including plugins and
 * themes, then if you edit the default theme, you should rename it, so that
 * your changes remain.
 *
 * @since 2.7.0
 *
 * @param string $from New release unzipped path.
 * @param string $to Path to old WordPress installation.
 * @return WP_Error|null WP_Error on failure, null on success.
 */
function update_core($from, $to) {
	global $wp_filesystem, $_old_files;

	@set_time_limit( 300 );

	// Sanity check the unzipped distribution
	apply_filters('update_feedback', __('Verifying the unpacked files'));
	if ( !$wp_filesystem->exists($from . '/wordpress/wp-settings.php') || !$wp_filesystem->exists($from . '/wordpress/wp-admin/admin.php') ||
		!$wp_filesystem->exists($from . '/wordpress/wp-includes/functions.php') ) {
		$wp_filesystem->delete($from, true);
		return new WP_Error('insane_distro', __('The update could not be unpacked') );
	}

	apply_filters('update_feedback', __('Installing the latest version'));

	// Create maintenance file to signal that we are upgrading
	$maintenance_string = '<?php $upgrading = ' . time() . '; ?>';
	$maintenance_file = $to . '.maintenance';
	$wp_filesystem->delete($maintenance_file);
	$wp_filesystem->put_contents($maintenance_file, $maintenance_string, 0644);

	// Copy new versions of WP files into place.
	$result = copy_dir($from . '/wordpress', $to);
	if ( is_wp_error($result) ) {
		$wp_filesystem->delete($maintenance_file);
		//$wp_filesystem->delete($working_dir, true); //TODO: Uncomment? This DOES mean that the new files are available in the upgrade folder if it fails.
		return $result;
	}

	// Remove old files
	foreach ( $_old_files as $old_file ) {
		$old_file = $to . $old_file;
		if ( !$wp_filesystem->exists($old_file) )
			continue;
		$wp_filesystem->delete($old_file, true);
	}

	// Upgrade DB with separate request
	apply_filters('update_feedback', __('Upgrading database'));
	$db_upgrade_url = admin_url('upgrade.php?step=upgrade_db');
	wp_remote_post($db_upgrade_url, array('timeout' => 60));

	// Remove working directory
	$wp_filesystem->delete($from, true);

	// Force refresh of update information
	delete_option('update_core');

	// Remove maintenance file, we're done.
	$wp_filesystem->delete($maintenance_file);
}

?>