<?php
/**
 * Upgrade API: WP_Upgrader, Plugin_Upgrader, Theme_Upgrader, Language_Pack_Upgrader,
 * Core_Upgrader, File_Upload_Upgrader, and WP_Automatic_Updater classes
 *
 * This set of classes are designed to be used to upgrade/install a local set of files
 * on the filesystem via the Filesystem Abstraction classes.
 *
 * @package WordPress
 * @subpackage Upgrader
 * @since 2.8.0
 */

require ABSPATH . 'wp-admin/includes/class-wp-upgrader-skins.php';

/**
 * Core class used for upgrading/installing a local set of files via
 * the Filesystem Abstraction classes from a Zip file.
 *
 * @since 2.8.0
 */
class WP_Upgrader {

	/**
	 * The error/notification strings used to update the user on the progress.
	 *
	 * @since 2.8.0
	 * @access public
	 * @var string $strings
	 */
	public $strings = array();

	/**
	 * The upgrader skin being used.
	 *
	 * @since 2.8.0
	 * @access public
	 * @var WP_Upgrader_Skin $skin
	 */
	public $skin = null;

	/**
	 * The result of the installation.
	 *
	 * This is set by {@see WP_Upgrader::install_package()}, only when the package is installed
	 * successfully. It will then be an array, unless a {@see WP_Error} is returned by the
	 * {@see 'upgrader_post_install'} filter. In that case, the `WP_Error` will be assigned to
	 * it.
	 *
	 * @since 2.8.0
	 * @access public
	 *
	 * @var WP_Error|array $result {
	 *      @type string $source             The full path to the source the files were installed from.
	 *      @type string $source_files       List of all the files in the source directory.
	 *      @type string $destination        The full path to the install destination folder.
	 *      @type string $destination_name   The name of the destination folder, or empty if `$destination`
	 *                                       and `$local_destination` are the same.
	 *      @type string $local_destination  The full local path to the destination folder. This is usually
	 *                                       the same as `$destination`.
	 *      @type string $remote_destination The full remote path to the destination folder
	 *                                       (i.e., from `$wp_filesystem`).
	 *      @type bool   $clear_destination  Whether the destination folder was cleared.
	 * }
	 */
	public $result = array();

	/**
	 * The total number of updates being performed.
	 *
	 * Set by the bulk update methods.
	 *
	 * @since 3.0.0
	 * @access public
	 * @var int $update_count
	 */
	public $update_count = 0;

	/**
	 * The current update if multiple updates are being performed.
	 *
	 * Used by the bulk update methods, and incremented for each update.
	 *
	 * @since 3.0.0
	 * @access public
	 * @var int
	 */
	public $update_current = 0;

	/**
	 * Construct the upgrader with a skin.
	 *
	 * @since 2.8.0
	 * @access public
	 *
	 * @param WP_Upgrader_Skin $skin The upgrader skin to use. Default is a {@see WP_Upgrader_Skin}
	 *                               instance.
	 */
	public function __construct( $skin = null ) {
		if ( null == $skin )
			$this->skin = new WP_Upgrader_Skin();
		else
			$this->skin = $skin;
	}

	/**
	 * Initialize the upgrader.
	 *
	 * This will set the relationship between the skin being used and this upgrader,
	 * and also add the generic strings to `WP_Upgrader::$strings`.
	 *
	 * @since 2.8.0
	 * @access public
	 */
	public function init() {
		$this->skin->set_upgrader($this);
		$this->generic_strings();
	}

	/**
	 * Add the generic strings to WP_Upgrader::$strings.
	 *
	 * @since 2.8.0
	 * @access public
	 */
	public function generic_strings() {
		$this->strings['bad_request'] = __('Invalid Data provided.');
		$this->strings['fs_unavailable'] = __('Could not access filesystem.');
		$this->strings['fs_error'] = __('Filesystem error.');
		$this->strings['fs_no_root_dir'] = __('Unable to locate WordPress Root directory.');
		$this->strings['fs_no_content_dir'] = __('Unable to locate WordPress Content directory (wp-content).');
		$this->strings['fs_no_plugins_dir'] = __('Unable to locate WordPress Plugin directory.');
		$this->strings['fs_no_themes_dir'] = __('Unable to locate WordPress Theme directory.');
		/* translators: %s: directory name */
		$this->strings['fs_no_folder'] = __('Unable to locate needed folder (%s).');

		$this->strings['download_failed'] = __('Download failed.');
		$this->strings['installing_package'] = __('Installing the latest version&#8230;');
		$this->strings['no_files'] = __('The package contains no files.');
		$this->strings['folder_exists'] = __('Destination folder already exists.');
		$this->strings['mkdir_failed'] = __('Could not create directory.');
		$this->strings['incompatible_archive'] = __('The package could not be installed.');
		$this->strings['files_not_writable'] = __( 'The update cannot be installed because we will be unable to copy some files. This is usually due to inconsistent file permissions.' );

		$this->strings['maintenance_start'] = __('Enabling Maintenance mode&#8230;');
		$this->strings['maintenance_end'] = __('Disabling Maintenance mode&#8230;');
	}

	/**
	 * Connect to the filesystem.
	 *
	 * @since 2.8.0
	 * @access public
	 *
	 * @global WP_Filesystem_Base $wp_filesystem Subclass
	 *
	 * @param array $directories                  Optional. A list of directories. If any of these do
	 *                                            not exist, a {@see WP_Error} object will be returned.
	 *                                            Default empty array.
	 * @param bool  $allow_relaxed_file_ownership Whether to allow relaxed file ownership.
	 *                                            Default false.
	 * @return bool|WP_Error True if able to connect, false or a {@see WP_Error} otherwise.
	 */
	public function fs_connect( $directories = array(), $allow_relaxed_file_ownership = false ) {
		global $wp_filesystem;

		if ( false === ( $credentials = $this->skin->request_filesystem_credentials( false, $directories[0], $allow_relaxed_file_ownership ) ) ) {
			return false;
		}

		if ( ! WP_Filesystem( $credentials, $directories[0], $allow_relaxed_file_ownership ) ) {
			$error = true;
			if ( is_object($wp_filesystem) && $wp_filesystem->errors->get_error_code() )
				$error = $wp_filesystem->errors;
			// Failed to connect, Error and request again
			$this->skin->request_filesystem_credentials( $error, $directories[0], $allow_relaxed_file_ownership );
			return false;
		}

		if ( ! is_object($wp_filesystem) )
			return new WP_Error('fs_unavailable', $this->strings['fs_unavailable'] );

		if ( is_wp_error($wp_filesystem->errors) && $wp_filesystem->errors->get_error_code() )
			return new WP_Error('fs_error', $this->strings['fs_error'], $wp_filesystem->errors);

		foreach ( (array)$directories as $dir ) {
			switch ( $dir ) {
				case ABSPATH:
					if ( ! $wp_filesystem->abspath() )
						return new WP_Error('fs_no_root_dir', $this->strings['fs_no_root_dir']);
					break;
				case WP_CONTENT_DIR:
					if ( ! $wp_filesystem->wp_content_dir() )
						return new WP_Error('fs_no_content_dir', $this->strings['fs_no_content_dir']);
					break;
				case WP_PLUGIN_DIR:
					if ( ! $wp_filesystem->wp_plugins_dir() )
						return new WP_Error('fs_no_plugins_dir', $this->strings['fs_no_plugins_dir']);
					break;
				case get_theme_root():
					if ( ! $wp_filesystem->wp_themes_dir() )
						return new WP_Error('fs_no_themes_dir', $this->strings['fs_no_themes_dir']);
					break;
				default:
					if ( ! $wp_filesystem->find_folder($dir) )
						return new WP_Error( 'fs_no_folder', sprintf( $this->strings['fs_no_folder'], esc_html( basename( $dir ) ) ) );
					break;
			}
		}
		return true;
	} //end fs_connect();

	/**
	 * Download a package.
	 *
	 * @since 2.8.0
	 * @access public
	 *
	 * @param string $package The URI of the package. If this is the full path to an
	 *                        existing local file, it will be returned untouched.
	 * @return string|WP_Error The full path to the downloaded package file, or a {@see WP_Error} object.
	 */
	public function download_package( $package ) {

		/**
		 * Filter whether to return the package.
		 *
		 * @since 3.7.0
		 * @access public
		 *
		 * @param bool        $reply   Whether to bail without returning the package.
		 *                             Default false.
		 * @param string      $package The package file name.
		 * @param WP_Upgrader $this    The WP_Upgrader instance.
		 */
		$reply = apply_filters( 'upgrader_pre_download', false, $package, $this );
		if ( false !== $reply )
			return $reply;

		if ( ! preg_match('!^(http|https|ftp)://!i', $package) && file_exists($package) ) //Local file or remote?
			return $package; //must be a local file..

		if ( empty($package) )
			return new WP_Error('no_package', $this->strings['no_package']);

		$this->skin->feedback('downloading_package', $package);

		$download_file = download_url($package);

		if ( is_wp_error($download_file) )
			return new WP_Error('download_failed', $this->strings['download_failed'], $download_file->get_error_message());

		return $download_file;
	}

	/**
	 * Unpack a compressed package file.
	 *
	 * @since 2.8.0
	 * @access public
	 *
	 * @global WP_Filesystem_Base $wp_filesystem Subclass
	 *
	 * @param string $package        Full path to the package file.
	 * @param bool   $delete_package Optional. Whether to delete the package file after attempting
	 *                               to unpack it. Default true.
	 * @return string|WP_Error The path to the unpacked contents, or a {@see WP_Error} on failure.
	 */
	public function unpack_package( $package, $delete_package = true ) {
		global $wp_filesystem;

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

		$upgrade_folder = $wp_filesystem->wp_content_dir() . 'upgrade/';

		//Clean up contents of upgrade directory beforehand.
		$upgrade_files = $wp_filesystem->dirlist($upgrade_folder);
		if ( !empty($upgrade_files) ) {
			foreach ( $upgrade_files as $file )
				$wp_filesystem->delete($upgrade_folder . $file['name'], true);
		}

		// We need a working directory - Strip off any .tmp or .zip suffixes
		$working_dir = $upgrade_folder . basename( basename( $package, '.tmp' ), '.zip' );

		// Clean up working directory
		if ( $wp_filesystem->is_dir($working_dir) )
			$wp_filesystem->delete($working_dir, true);

		// Unzip package to working directory
		$result = unzip_file( $package, $working_dir );

		// Once extracted, delete the package if required.
		if ( $delete_package )
			unlink($package);

		if ( is_wp_error($result) ) {
			$wp_filesystem->delete($working_dir, true);
			if ( 'incompatible_archive' == $result->get_error_code() ) {
				return new WP_Error( 'incompatible_archive', $this->strings['incompatible_archive'], $result->get_error_data() );
			}
			return $result;
		}

		return $working_dir;
	}

	/**
	 * Clears the directory where this item is going to be installed into.
	 *
	 * @since 4.3.0
	 * @access public
	 *
	 * @global WP_Filesystem_Base $wp_filesystem Subclass
	 *
	 * @param string $remote_destination The location on the remote filesystem to be cleared
	 * @return bool|WP_Error True upon success, WP_Error on failure.
	 */
	public function clear_destination( $remote_destination ) {
		global $wp_filesystem;

		if ( ! $wp_filesystem->exists( $remote_destination ) ) {
			return true;
		}

		// Check all files are writable before attempting to clear the destination.
		$unwritable_files = array();

		$_files = $wp_filesystem->dirlist( $remote_destination, true, true );

		// Flatten the resulting array, iterate using each as we append to the array during iteration.
		while ( $f = each( $_files ) ) {
			$file = $f['value'];
			$name = $f['key'];

			if ( ! isset( $file['files'] ) ) {
				continue;
			}

			foreach ( $file['files'] as $filename => $details ) {
				$_files[ $name . '/' . $filename ] = $details;
			}
		}

		// Check writability.
		foreach ( $_files as $filename => $file_details ) {
			if ( ! $wp_filesystem->is_writable( $remote_destination . $filename ) ) {

				// Attempt to alter permissions to allow writes and try again.
				$wp_filesystem->chmod( $remote_destination . $filename, ( 'd' == $file_details['type'] ? FS_CHMOD_DIR : FS_CHMOD_FILE ) );
				if ( ! $wp_filesystem->is_writable( $remote_destination . $filename ) ) {
					$unwritable_files[] = $filename;
				}
			}
		}

		if ( ! empty( $unwritable_files ) ) {
			return new WP_Error( 'files_not_writable', $this->strings['files_not_writable'], implode( ', ', $unwritable_files ) );
		}

		if ( ! $wp_filesystem->delete( $remote_destination, true ) ) {
			return new WP_Error( 'remove_old_failed', $this->strings['remove_old_failed'] );
		}

		return true;
	}

	/**
	 * Install a package.
	 *
	 * Copies the contents of a package form a source directory, and installs them in
	 * a destination directory. Optionally removes the source. It can also optionally
	 * clear out the destination folder if it already exists.
	 *
	 * @since 2.8.0
	 * @access public
	 *
	 * @global WP_Filesystem_Base $wp_filesystem Subclass
	 * @global array              $wp_theme_directories
	 *
	 * @param array|string $args {
	 *     Optional. Array or string of arguments for installing a package. Default empty array.
	 *
	 *     @type string $source                      Required path to the package source. Default empty.
	 *     @type string $destination                 Required path to a folder to install the package in.
	 *                                               Default empty.
	 *     @type bool   $clear_destination           Whether to delete any files already in the destination
	 *                                               folder. Default false.
	 *     @type bool   $clear_working               Whether to delete the files form the working directory
	 *                                               after copying to the destination. Default false.
	 *     @type bool   $abort_if_destination_exists Whether to abort the installation if
	 *                                               the destination folder already exists. Default true.
	 *     @type array  $hook_extra                  Extra arguments to pass to the filter hooks called by
	 *                                               {@see WP_Upgrader::install_package()}. Default empty array.
	 * }
	 *
	 * @return array|WP_Error The result (also stored in `WP_Upgrader:$result`), or a {@see WP_Error} on failure.
	 */
	public function install_package( $args = array() ) {
		global $wp_filesystem, $wp_theme_directories;

		$defaults = array(
			'source' => '', // Please always pass this
			'destination' => '', // and this
			'clear_destination' => false,
			'clear_working' => false,
			'abort_if_destination_exists' => true,
			'hook_extra' => array()
		);

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

		// These were previously extract()'d.
		$source = $args['source'];
		$destination = $args['destination'];
		$clear_destination = $args['clear_destination'];

		@set_time_limit( 300 );

		if ( empty( $source ) || empty( $destination ) ) {
			return new WP_Error( 'bad_request', $this->strings['bad_request'] );
		}
		$this->skin->feedback( 'installing_package' );

		/**
		 * Filter the install response before the installation has started.
		 *
		 * Returning a truthy value, or one that could be evaluated as a WP_Error
		 * will effectively short-circuit the installation, returning that value
		 * instead.
		 *
		 * @since 2.8.0
		 *
		 * @param bool|WP_Error $response   Response.
		 * @param array         $hook_extra Extra arguments passed to hooked filters.
		 */
		$res = apply_filters( 'upgrader_pre_install', true, $args['hook_extra'] );

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

		//Retain the Original source and destinations
		$remote_source = $args['source'];
		$local_destination = $destination;

		$source_files = array_keys( $wp_filesystem->dirlist( $remote_source ) );
		$remote_destination = $wp_filesystem->find_folder( $local_destination );

		//Locate which directory to copy to the new folder, This is based on the actual folder holding the files.
		if ( 1 == count( $source_files ) && $wp_filesystem->is_dir( trailingslashit( $args['source'] ) . $source_files[0] . '/' ) ) { //Only one folder? Then we want its contents.
			$source = trailingslashit( $args['source'] ) . trailingslashit( $source_files[0] );
		} elseif ( count( $source_files ) == 0 ) {
			return new WP_Error( 'incompatible_archive_empty', $this->strings['incompatible_archive'], $this->strings['no_files'] ); // There are no files?
		} else { // It's only a single file, the upgrader will use the folder name of this file as the destination folder. Folder name is based on zip filename.
			$source = trailingslashit( $args['source'] );
		}

		/**
		 * Filter the source file location for the upgrade package.
		 *
		 * @since 2.8.0
		 * @since 4.4.0 The $hook_extra parameter became available.
		 *
		 * @param string      $source        File source location.
		 * @param string      $remote_source Remote file source location.
		 * @param WP_Upgrader $this          WP_Upgrader instance.
		 * @param array       $hook_extra    Extra arguments passed to hooked filters.
		 */
		$source = apply_filters( 'upgrader_source_selection', $source, $remote_source, $this, $args['hook_extra'] );

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

		// Has the source location changed? If so, we need a new source_files list.
		if ( $source !== $remote_source ) {
			$source_files = array_keys( $wp_filesystem->dirlist( $source ) );
		}

		/*
		 * Protection against deleting files in any important base directories.
		 * Theme_Upgrader & Plugin_Upgrader also trigger this, as they pass the
		 * destination directory (WP_PLUGIN_DIR / wp-content/themes) intending
		 * to copy the directory into the directory, whilst they pass the source
		 * as the actual files to copy.
		 */
		$protected_directories = array( ABSPATH, WP_CONTENT_DIR, WP_PLUGIN_DIR, WP_CONTENT_DIR . '/themes' );

		if ( is_array( $wp_theme_directories ) ) {
			$protected_directories = array_merge( $protected_directories, $wp_theme_directories );
		}

		if ( in_array( $destination, $protected_directories ) ) {
			$remote_destination = trailingslashit( $remote_destination ) . trailingslashit( basename( $source ) );
			$destination = trailingslashit( $destination ) . trailingslashit( basename( $source ) );
		}

		if ( $clear_destination ) {
			// We're going to clear the destination if there's something there.
			$this->skin->feedback('remove_old');

			$removed = $this->clear_destination( $remote_destination );

			/**
			 * Filter whether the upgrader cleared the destination.
			 *
			 * @since 2.8.0
			 *
			 * @param mixed  $removed            Whether the destination was cleared. true on success, WP_Error on failure
			 * @param string $local_destination  The local package destination.
			 * @param string $remote_destination The remote package destination.
			 * @param array  $hook_extra         Extra arguments passed to hooked filters.
			 */
			$removed = apply_filters( 'upgrader_clear_destination', $removed, $local_destination, $remote_destination, $args['hook_extra'] );

			if ( is_wp_error( $removed ) ) {
				return $removed;
			}
		} elseif ( $args['abort_if_destination_exists'] && $wp_filesystem->exists($remote_destination) ) {
			//If we're not clearing the destination folder and something exists there already, Bail.
			//But first check to see if there are actually any files in the folder.
			$_files = $wp_filesystem->dirlist($remote_destination);
			if ( ! empty($_files) ) {
				$wp_filesystem->delete($remote_source, true); //Clear out the source files.
				return new WP_Error('folder_exists', $this->strings['folder_exists'], $remote_destination );
			}
		}

		//Create destination if needed
		if ( ! $wp_filesystem->exists( $remote_destination ) ) {
			if ( ! $wp_filesystem->mkdir( $remote_destination, FS_CHMOD_DIR ) ) {
				return new WP_Error( 'mkdir_failed_destination', $this->strings['mkdir_failed'], $remote_destination );
			}
		}
		// Copy new version of item into place.
		$result = copy_dir($source, $remote_destination);
		if ( is_wp_error($result) ) {
			if ( $args['clear_working'] ) {
				$wp_filesystem->delete( $remote_source, true );
			}
			return $result;
		}

		//Clear the Working folder?
		if ( $args['clear_working'] ) {
			$wp_filesystem->delete( $remote_source, true );
		}

		$destination_name = basename( str_replace($local_destination, '', $destination) );
		if ( '.' == $destination_name ) {
			$destination_name = '';
		}

		$this->result = compact( 'source', 'source_files', 'destination', 'destination_name', 'local_destination', 'remote_destination', 'clear_destination' );

		/**
		 * Filter the install response after the installation has finished.
		 *
		 * @since 2.8.0
		 *
		 * @param bool  $response   Install response.
		 * @param array $hook_extra Extra arguments passed to hooked filters.
		 * @param array $result     Installation result data.
		 */
		$res = apply_filters( 'upgrader_post_install', true, $args['hook_extra'], $this->result );

		if ( is_wp_error($res) ) {
			$this->result = $res;
			return $res;
		}

		//Bombard the calling function will all the info which we've just used.
		return $this->result;
	}

	/**
	 * Run an upgrade/install.
	 *
	 * Attempts to download the package (if it is not a local file), unpack it, and
	 * install it in the destination folder.
	 *
	 * @since 2.8.0
	 * @access public
	 *
	 * @param array $options {
	 *     Array or string of arguments for upgrading/installing a package.
	 *
	 *     @type string $package                     The full path or URI of the package to install.
	 *                                               Default empty.
	 *     @type string $destination                 The full path to the destination folder.
	 *                                               Default empty.
	 *     @type bool   $clear_destination           Whether to delete any files already in the
	 *                                               destination folder. Default false.
	 *     @type bool   $clear_working               Whether to delete the files form the working
	 *                                               directory after copying to the destination.
	 *                                               Default false.
	 *     @type bool   $abort_if_destination_exists Whether to abort the installation if the destination
	 *                                               folder already exists. When true, `$clear_destination`
	 *                                               should be false. Default true.
	 *     @type bool   $is_multi                    Whether this run is one of multiple upgrade/install
	 *                                               actions being performed in bulk. When true, the skin
	 *                                               {@see WP_Upgrader::header()} and {@see WP_Upgrader::footer()}
	 *                                               aren't called. Default false.
	 *     @type array  $hook_extra                  Extra arguments to pass to the filter hooks called by
	 *                                               {@see WP_Upgrader::run()}.
	 * }
	 * @return array|false|WP_error The result from self::install_package() on success, otherwise a WP_Error,
	 *                              or false if unable to connect to the filesystem.
	 */
	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 );

		/**
		 * Filter the package options before running an update.
		 *
		 * @since 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.
		 * }
		 */
		$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 {
			// Install succeeded.
			$this->skin->feedback('process_success');
		}

		$this->skin->after();

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

			/** This action is documented in wp-admin/includes/class-wp-upgrader.php */
			do_action( 'upgrader_process_complete', $this, $options['hook_extra'] );
			$this->skin->footer();
		}

		return $result;
	}

	/**
	 * Toggle maintenance mode for the site.
	 *
	 * Creates/deletes the maintenance file to enable/disable maintenance mode.
	 *
	 * @since 2.8.0
	 * @access public
	 *
	 * @global WP_Filesystem_Base $wp_filesystem Subclass
	 *
	 * @param bool $enable True to enable maintenance mode, false to disable.
	 */
	public function maintenance_mode( $enable = false ) {
		global $wp_filesystem;
		$file = $wp_filesystem->abspath() . '.maintenance';
		if ( $enable ) {
			$this->skin->feedback('maintenance_start');
			// Create maintenance file to signal that we are upgrading
			$maintenance_string = '<?php $upgrading = ' . time() . '; ?>';
			$wp_filesystem->delete($file);
			$wp_filesystem->put_contents($file, $maintenance_string, FS_CHMOD_FILE);
		} elseif ( ! $enable && $wp_filesystem->exists( $file ) ) {
			$this->skin->feedback('maintenance_end');
			$wp_filesystem->delete($file);
		}
	}

	/**
 	 * Creates a lock using WordPress options.
 	 *
 	 * @since 4.5.0
 	 * @access public
 	 * @static
 	 *
 	 * @param string $lock_name       The name of this unique lock.
 	 * @param int    $release_timeout Optional. The duration in seconds to respect an existing lock.
	 *                                Default: 1 hour.
 	 * @return bool False if a lock couldn't be created or if the lock is no longer valid. True otherwise.
 	 */
	public static function create_lock( $lock_name, $release_timeout = null ) {
		global $wpdb;
		if ( ! $release_timeout ) {
			$release_timeout = HOUR_IN_SECONDS;
		}
		$lock_option = $lock_name . '.lock';

		// Try to lock.
		$lock_result = $wpdb->query( $wpdb->prepare( "INSERT IGNORE INTO `$wpdb->options` ( `option_name`, `option_value`, `autoload` ) VALUES (%s, %s, 'no') /* LOCK */", $lock_option, time() ) );

		if ( ! $lock_result ) {
			$lock_result = get_option( $lock_option );

			// If a lock couldn't be created, and there isn't a lock, bail.
			if ( ! $lock_result ) {
				return false;
			}

			// Check to see if the lock is still valid. If not, bail.
			if ( $lock_result > ( time() - $release_timeout ) ) {
				return false;
			}

			// There must exist an expired lock, clear it and re-gain it.
			WP_Upgrader::release_lock( $lock_name );

			return WP_Upgrader::create_lock( $lock_name, $release_timeout );
		}

		// Update the lock, as by this point we've definitely got a lock, just need to fire the actions.
		update_option( $lock_option, time() );

		return true;
	}

	/**
 	 * Releases an upgrader lock.
 	 *
 	 * @since 4.5.0
 	 * @access public
 	 * @static
	 *
	 * @see WP_Upgrader::create_lock()
 	 *
 	 * @param string $lock_name The name of this unique lock.
	 * @return bool True if the lock was successfully released. False on failure.
 	 */
	public static function release_lock( $lock_name ) {
		return delete_option( $lock_name . '.lock' );
	}

}

/**
 * Core class used for upgrading/installing plugins.
 *
 * It is designed to upgrade/install plugins from a local zip, remote zip URL,
 * or uploaded zip file.
 *
 * @since 2.8.0
 *
 * @see WP_Upgrader
 */
class Plugin_Upgrader extends WP_Upgrader {

	/**
	 * Plugin upgrade result.
	 *
	 * @since 2.8.0
	 * @access public
	 * @var array|WP_Error $result
	 *
	 * @see WP_Upgrader::$result
	 */
	public $result;

	/**
	 * Whether a bulk upgrade/install is being performed.
	 *
	 * @since 2.9.0
	 * @access public
	 * @var bool $bulk
	 */
	public $bulk = false;

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

	/**
	 * Initialize the install strings.
	 *
	 * @since 2.8.0
	 * @access public
	 */
	public function install_strings() {
		$this->strings['no_package'] = __('Install package not available.');
		$this->strings['downloading_package'] = __('Downloading install package from <span class="code">%s</span>&#8230;');
		$this->strings['unpack_package'] = __('Unpacking the package&#8230;');
		$this->strings['installing_package'] = __('Installing the plugin&#8230;');
		$this->strings['no_files'] = __('The plugin contains no files.');
		$this->strings['process_failed'] = __('Plugin install failed.');
		$this->strings['process_success'] = __('Plugin installed successfully.');
	}

	/**
	 * Install a plugin package.
	 *
	 * @since 2.8.0
	 * @since 3.7.0 The `$args` parameter was added, making clearing the plugin update cache optional.
	 * @access public
	 *
	 * @param string $package The full local path or URI of the package.
	 * @param array  $args {
	 *     Optional. Other arguments for installing a plugin package. Default empty array.
	 *
	 *     @type bool $clear_update_cache Whether to clear the plugin updates cache if successful.
	 *                                    Default true.
	 * }
	 * @return bool|WP_Error True if the install was successful, false or a WP_Error otherwise.
	 */
	public function install( $package, $args = array() ) {

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

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

		add_filter('upgrader_source_selection', array($this, 'check_package') );
		// Clear cache so wp_update_plugins() knows about the new plugin.
		add_action( 'upgrader_process_complete', 'wp_clean_plugins_cache', 9, 0 );

		$this->run( array(
			'package' => $package,
			'destination' => WP_PLUGIN_DIR,
			'clear_destination' => false, // Do not overwrite files.
			'clear_working' => true,
			'hook_extra' => array(
				'type' => 'plugin',
				'action' => 'install',
			)
		) );

		remove_action( 'upgrader_process_complete', 'wp_clean_plugins_cache', 9 );
		remove_filter('upgrader_source_selection', array($this, 'check_package') );

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

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

		return true;
	}

	/**
	 * Upgrade a plugin.
	 *
	 * @since 2.8.0
	 * @since 3.7.0 The `$args` parameter was added, making clearing the plugin update cache optional.
	 * @access public
	 *
	 * @param string $plugin The basename path to the main plugin file.
	 * @param array  $args {
	 *     Optional. Other arguments for upgrading a plugin package. Default empty array.
	 *
	 *     @type bool $clear_update_cache Whether to clear the plugin updates cache if successful.
	 *                                    Default true.
	 * }
	 * @return bool|WP_Error True if the upgrade was successful, false or a {@see WP_Error} object otherwise.
	 */
	public function upgrade( $plugin, $args = array() ) {

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

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

		$current = get_site_transient( 'update_plugins' );
		if ( !isset( $current->response[ $plugin ] ) ) {
			$this->skin->before();
			$this->skin->set_result(false);
			$this->skin->error('up_to_date');
			$this->skin->after();
			return false;
		}

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

		add_filter('upgrader_pre_install', array($this, 'deactivate_plugin_before_upgrade'), 10, 2);
		add_filter('upgrader_clear_destination', array($this, 'delete_old_plugin'), 10, 4);
		//'source_selection' => array($this, 'source_selection'), //there's a trac ticket to move up the directory for zip's which are made a bit differently, useful for non-.org plugins.

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

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

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

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

		return true;
	}

	/**
	 * Bulk upgrade several plugins at once.
	 *
	 * @since 2.8.0
	 * @since 3.7.0 The `$args` parameter was added, making clearing the plugin update cache optional.
	 * @access public
	 *
	 * @param array $plugins Array of the basename paths of the plugins' main files.
	 * @param array $args {
	 *     Optional. Other arguments for upgrading several plugins at once. Default empty array.
	 *
	 *     @type bool $clear_update_cache Whether to clear the plugin updates cache if successful.
	 *                                    Default true.
	 * }
	 * @return array|false An array of results indexed by plugin file, or false if unable to connect to the filesystem.
	 */
	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);

		/**
		 * Fires when the bulk upgrader process is complete.
		 *
		 * @since 3.6.0
		 *
		 * @param Plugin_Upgrader $this Plugin_Upgrader instance. In other contexts, $this, might
		 *                              be a Theme_Upgrader or Core_Upgrade instance.
		 * @param array           $data {
		 *     Array of bulk item update data.
		 *
		 *     @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 array  $packages Array of plugin, theme, or core packages to update.
		 * }
		 */
		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'));

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

		return $results;
	}

	/**
	 * Check a source package to be sure it contains a plugin.
	 *
	 * This function is added to the {@see 'upgrader_source_selection'} filter by
	 * {@see Plugin_Upgrader::install()}.
	 *
	 * @since 3.3.0
	 * @access public
	 *
	 * @global WP_Filesystem_Base $wp_filesystem Subclass
	 *
	 * @param string $source The path to the downloaded package source.
	 * @return string|WP_Error The source as passed, or a {@see WP_Error} object
	 *                         if no plugins were found.
	 */
	public function check_package($source) {
		global $wp_filesystem;

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

		$working_directory = str_replace( $wp_filesystem->wp_content_dir(), trailingslashit(WP_CONTENT_DIR), $source);
		if ( ! is_dir($working_directory) ) // Sanity check, if the above fails, let's not prevent installation.
			return $source;

		// Check the folder contains at least 1 valid plugin.
		$plugins_found = false;
		$files = glob( $working_directory . '*.php' );
		if ( $files ) {
			foreach ( $files as $file ) {
				$info = get_plugin_data( $file, false, false );
				if ( ! empty( $info['Name'] ) ) {
					$plugins_found = true;
					break;
				}
			}
		}

		if ( ! $plugins_found )
			return new WP_Error( 'incompatible_archive_no_plugins', $this->strings['incompatible_archive'], __( 'No valid plugins were found.' ) );

		return $source;
	}

	/**
	 * Retrieve the path to the file that contains the plugin info.
	 *
	 * This isn't used internally in the class, but is called by the skins.
	 *
	 * @since 2.8.0
	 * @access public
	 *
	 * @return string|false The full path to the main plugin file, or false.
	 */
	public function plugin_info() {
		if ( ! is_array($this->result) )
			return false;
		if ( empty($this->result['destination_name']) )
			return false;

		$plugin = get_plugins('/' . $this->result['destination_name']); //Ensure to pass with leading slash
		if ( empty($plugin) )
			return false;

		$pluginfiles = array_keys($plugin); //Assume the requested plugin is the first in the list

		return $this->result['destination_name'] . '/' . $pluginfiles[0];
	}

	/**
	 * Deactivates a plugin before it is upgraded.
	 *
	 * Hooked to the {@see 'upgrader_pre_install'} filter by {@see Plugin_Upgrader::upgrade()}.
	 *
	 * @since 2.8.0
	 * @since 4.1.0 Added a return value.
	 * @access public
	 *
	 * @param bool|WP_Error  $return Upgrade offer return.
	 * @param array          $plugin Plugin package arguments.
	 * @return bool|WP_Error The passed in $return param or {@see WP_Error}.
	 */
	public function deactivate_plugin_before_upgrade($return, $plugin) {

		if ( is_wp_error($return) ) //Bypass.
			return $return;

		// When in cron (background updates) don't deactivate the plugin, as we require a browser to reactivate it
		if ( defined( 'DOING_CRON' ) && DOING_CRON )
			return $return;

		$plugin = isset($plugin['plugin']) ? $plugin['plugin'] : '';
		if ( empty($plugin) )
			return new WP_Error('bad_request', $this->strings['bad_request']);

		if ( is_plugin_active($plugin) ) {
			//Deactivate the plugin silently, Prevent deactivation hooks from running.
			deactivate_plugins($plugin, true);
		}

		return $return;
	}

	/**
	 * Delete the old plugin during an upgrade.
	 *
	 * Hooked to the {@see 'upgrader_clear_destination'} filter by
	 * {@see Plugin_Upgrader::upgrade()} and {@see Plugin_Upgrader::bulk_upgrade()}.
	 *
	 * @since 2.8.0
	 * @access public
	 *
	 * @global WP_Filesystem_Base $wp_filesystem Subclass
     *
	 * @param bool|WP_Error $removed
	 * @param string        $local_destination
	 * @param string        $remote_destination
	 * @param array         $plugin
	 * @return WP_Error|bool
	 */
	public function delete_old_plugin($removed, $local_destination, $remote_destination, $plugin) {
		global $wp_filesystem;

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

		$plugin = isset($plugin['plugin']) ? $plugin['plugin'] : '';
		if ( empty($plugin) )
			return new WP_Error('bad_request', $this->strings['bad_request']);

		$plugins_dir = $wp_filesystem->wp_plugins_dir();
		$this_plugin_dir = trailingslashit( dirname($plugins_dir . $plugin) );

		if ( ! $wp_filesystem->exists($this_plugin_dir) ) //If it's already vanished.
			return $removed;

		// If plugin is in its own directory, recursively delete the directory.
		if ( strpos($plugin, '/') && $this_plugin_dir != $plugins_dir ) //base check on if plugin includes directory separator AND that it's not the root plugin folder
			$deleted = $wp_filesystem->delete($this_plugin_dir, true);
		else
			$deleted = $wp_filesystem->delete($plugins_dir . $plugin);

		if ( ! $deleted )
			return new WP_Error('remove_old_failed', $this->strings['remove_old_failed']);

		return true;
	}
}

/**
 * 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
 *
 * @see WP_Upgrader
 */
class Theme_Upgrader extends WP_Upgrader {

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

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

	/**
	 * Initialize the upgrade strings.
	 *
	 * @since 2.8.0
	 * @access public
	 */
	public function upgrade_strings() {
		$this->strings['up_to_date'] = __('The theme is at the latest version.');
		$this->strings['no_package'] = __('Update package not available.');
		$this->strings['downloading_package'] = __('Downloading update from <span class="code">%s</span>&#8230;');
		$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.');
	}

	/**
	 * Initialize the install strings.
	 *
	 * @since 2.8.0
	 * @access public
	 */
	public function install_strings() {
		$this->strings['no_package'] = __('Install package not available.');
		$this->strings['downloading_package'] = __('Downloading install package from <span class="code">%s</span>&#8230;');
		$this->strings['unpack_package'] = __('Unpacking the package&#8230;');
		$this->strings['installing_package'] = __('Installing the theme&#8230;');
		$this->strings['no_files'] = __('The theme contains no files.');
		$this->strings['process_failed'] = __('Theme install failed.');
		$this->strings['process_success'] = __('Theme installed successfully.');
		/* translators: 1: theme name, 2: 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: version */
		$this->strings['parent_theme_prepare_install'] = __('Preparing to install <strong>%1$s %2$s</strong>&#8230;');
		/* translators: 1: theme name, 2: version */
		$this->strings['parent_theme_currently_installed'] = __('The parent theme, <strong>%1$s %2$s</strong>, is currently installed.');
		/* translators: 1: theme name, 2: version */
		$this->strings['parent_theme_install_success'] = __('Successfully installed the parent theme, <strong>%1$s %2$s</strong>.');
		$this->strings['parent_theme_not_found'] = __('<strong>The parent theme could not be found.</strong> You will need to install the parent theme, <strong>%s</strong>, before you can use this child theme.');
	}

	/**
	 * Check if a child theme is being installed and we need to install its parent.
	 *
	 * Hooked to the {@see 'upgrader_post_install'} filter by {@see Theme_Upgrader::install()}.
	 *
	 * @since 3.4.0
	 * @access public
	 *
	 * @param bool  $install_result
	 * @param array $hook_extra
	 * @param array $child_result
	 * @return type
	 */
	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', $theme_info->get('Template') );
			// Don't show activate or preview actions after install
			add_filter('install_theme_complete_actions', array($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'];//, $api->name, $api->version);

		$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 parents 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
	 * {@see Theme_Upgrader::check_parent_theme_filter()} when installing
	 * a child theme and installing the parent theme fails.
	 *
	 * @since 3.4.0
	 * @access public
	 *
	 * @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.
	 * @access public
	 *
	 * @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 install was successful, false or a {@see WP_Error} object otherwise.
	 */
	public function install( $package, $args = array() ) {

		$defaults = array(
			'clear_update_cache' => true,
		);
		$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);
		// 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' => false, //Do not overwrite files.
			'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'] );

		return true;
	}

	/**
	 * Upgrade a theme.
	 *
	 * @since 2.8.0
	 * @since 3.7.0 The `$args` parameter was added, making clearing the update cache optional.
	 * @access public
	 *
	 * @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 {@see 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);

		$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',
			),
		) );

		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'] );

		return true;
	}

	/**
	 * Upgrade several themes at once.
	 *
	 * @since 3.0.0
	 * @since 3.7.0 The `$args` parameter was added, making clearing the update cache optional.
	 * @access public
	 *
	 * @param array $themes 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() ) {

		$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 || $theme == get_stylesheet() || $theme == get_template();
		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 ];

			$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
				),
			) );

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

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

		$this->maintenance_mode(false);

		/** 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 a 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'));

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

		return $results;
	}

	/**
	 * Check that the package source contains a valid theme.
	 *
	 * Hooked to the {@see 'upgrader_source_selection'} filter by {@see Theme_Upgrader::install()}.
	 * It will return an error if the theme doesn't have style.css or index.php
	 * files.
	 *
	 * @since 3.3.0
	 * @access public
	 *
	 * @global WP_Filesystem_Base $wp_filesystem Subclass
	 *
	 * @param string $source The full path to the package source.
	 * @return string|WP_Error The source or a WP_Error.
	 */
	public function check_package( $source ) {
		global $wp_filesystem;

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

		// Check 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) ) // Sanity 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'],
				/* translators: %s: style.css */
				sprintf( __( 'The theme is missing the %s stylesheet.' ),
					'<code>style.css</code>'
				)
			);
		}

		$info = get_file_data( $working_directory . 'style.css', array( 'Name' => 'Theme Name', 'Template' => 'Template' ) );

		if ( empty( $info['Name'] ) ) {
			return new WP_Error( 'incompatible_archive_theme_no_name', $this->strings['incompatible_archive'],
				/* translators: %s: style.css */
				sprintf( __( 'The %s stylesheet doesn&#8217;t contain a valid theme header.' ),
					'<code>style.css</code>'
				)
			);
		}

		// If it's not a child theme, it must have at least an index.php to be legit.
		if ( empty( $info['Template'] ) && ! file_exists( $working_directory . 'index.php' ) ) {
			return new WP_Error( 'incompatible_archive_theme_no_index', $this->strings['incompatible_archive'],
				/* translators: %s: index.php */
				sprintf( __( 'The theme is missing the %s file.' ),
					'<code>index.php</code>'
				)
			);
		}

		return $source;
	}

	/**
	 * Turn on maintenance mode before attempting to upgrade the current theme.
	 *
	 * Hooked to the {@see 'upgrader_pre_install'} filter by {@see Theme_Upgrader::upgrade()} and
	 * {@see Theme_Upgrader::bulk_upgrade()}.
	 *
	 * @since 2.8.0
	 * @access public
	 *
	 * @param bool|WP_Error  $return
	 * @param array          $theme
	 * @return bool|WP_Error
	 */
	public function current_before($return, $theme) {
		if ( is_wp_error($return) )
			return $return;

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

		if ( $theme != get_stylesheet() ) //If not current
			return $return;
		//Change to maintenance mode now.
		if ( ! $this->bulk )
			$this->maintenance_mode(true);

		return $return;
	}

	/**
	 * Turn off maintenance mode after upgrading the current theme.
	 *
	 * Hooked to the {@see 'upgrader_post_install'} filter by {@see Theme_Upgrader::upgrade()}
	 * and {@see Theme_Upgrader::bulk_upgrade()}.
	 *
	 * @since 2.8.0
	 * @access public
	 *
	 * @param bool|WP_Error  $return
	 * @param array          $theme
	 * @return bool|WP_Error
	 */
	public function current_after($return, $theme) {
		if ( is_wp_error($return) )
			return $return;

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

		if ( $theme != get_stylesheet() ) // If not current
			return $return;

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

		//Time to remove maintenance mode
		if ( ! $this->bulk )
			$this->maintenance_mode(false);
		return $return;
	}

	/**
	 * Delete the old theme during an upgrade.
	 *
	 * Hooked to the {@see 'upgrader_clear_destination'} filter by {@see Theme_Upgrader::upgrade()}
	 * and {@see Theme_Upgrader::bulk_upgrade()}.
	 *
	 * @since 2.8.0
	 * @access public
	 *
	 * @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;
	}

	/**
	 * Get the WP_Theme object for a theme.
	 *
	 * @since 2.8.0
	 * @since 3.0.0 The `$theme` argument was added.
	 * @access public
	 *
	 * @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;
		}
		return wp_get_theme( $theme );
	}

}

/**
 * Core class used for updating/installing language packs (translations)
 * for plugins, themes, and core.
 *
 * @since 3.7.0
 *
 * @see WP_Upgrader
 */
class Language_Pack_Upgrader extends WP_Upgrader {

	/**
	 * Result of the language pack upgrade.
	 *
	 * @since 3.7.0
	 * @access public
	 * @var array|WP_Error $result
	 * @see WP_Upgrader::$result
	 */
	public $result;

	/**
	 * Whether a bulk upgrade/install is being performed.
	 *
	 * @since 3.7.0
	 * @access public
	 * @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
	 * @access public
	 * @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 installs, 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 );

			/**
			 * Filter 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
	 * @access public
	 */
	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 translation is up to date.' ); // We need to silently skip this case
		$this->strings['no_package'] = __( 'Update package not available.' );
		$this->strings['downloading_package'] = __( 'Downloading translation from <span class="code">%s</span>&#8230;' );
		$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
	 * @access public
	 *
	 * @param string|false $update Optional. Whether an update offer is available. Default false.
	 * @param array        $args   Optional. Other optional arguments, see
	 *                             {@see Language_Pack_Upgrader::bulk_upgrade()}. Default empty array.
	 * @return array|bool|WP_Error The result of the upgrade, or a {@see 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
	 * @access public
	 *
	 * @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->before();
			$this->skin->set_result( true );
			$this->skin->feedback( 'up_to_date' );
			$this->skin->after();
			$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 );

		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;
		}

		$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
	 * {@see Language_Pack_Upgrader::bulk_upgrade()}.
	 *
	 * @since 3.7.0
	 * @access public
	 *
	 * @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
	 * @access public
	 *
	 * @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 '';
	}

}

/**
 * Core class used for updating core.
 *
 * It allows for WordPress to upgrade itself in combination with
 * the wp-admin/includes/update-core.php file.
 *
 * @since 2.8.0
 *
 * @see WP_Upgrader
 */
class Core_Upgrader extends WP_Upgrader {

	/**
	 * Initialize the upgrade strings.
	 *
	 * @since 2.8.0
	 * @access public
	 */
	public function upgrade_strings() {
		$this->strings['up_to_date'] = __('WordPress is at the latest version.');
		$this->strings['locked'] = __('Another update is currently in progress.');
		$this->strings['no_package'] = __('Update package not available.');
		$this->strings['downloading_package'] = __('Downloading update from <span class="code">%s</span>&#8230;');
		$this->strings['unpack_package'] = __('Unpacking the update&#8230;');
		$this->strings['copy_failed'] = __('Could not copy files.');
		$this->strings['copy_failed_space'] = __('Could not copy files. You may have run out of disk space.' );
		$this->strings['start_rollback'] = __( 'Attempting to roll back to previous version.' );
		$this->strings['rollback_was_required'] = __( 'Due to an error during updating, WordPress has rolled back to your previous version.' );
	}

	/**
	 * Upgrade WordPress core.
	 *
	 * @since 2.8.0
	 * @access public
	 *
	 * @global WP_Filesystem_Base $wp_filesystem Subclass
	 * @global callable           $_wp_filesystem_direct_method
	 *
	 * @param object $current Response object for whether WordPress is current.
	 * @param array  $args {
	 *        Optional. Arguments for upgrading WordPress core. Default empty array.
	 *
	 *        @type bool $pre_check_md5    Whether to check the file checksums before
	 *                                     attempting the upgrade. Default true.
	 *        @type bool $attempt_rollback Whether to attempt to rollback the chances if
	 *                                     there is a problem. Default false.
	 *        @type bool $do_rollback      Whether to perform this "upgrade" as a rollback.
	 *                                     Default false.
	 * }
	 * @return null|false|WP_Error False or WP_Error on failure, null on success.
	 */
	public function upgrade( $current, $args = array() ) {
		global $wp_filesystem;

		include( ABSPATH . WPINC . '/version.php' ); // $wp_version;

		$start_time = time();

		$defaults = array(
			'pre_check_md5'    => true,
			'attempt_rollback' => false,
			'do_rollback'      => false,
			'allow_relaxed_file_ownership' => false,
		);
		$parsed_args = wp_parse_args( $args, $defaults );

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

		// Is an update available?
		if ( !isset( $current->response ) || $current->response == 'latest' )
			return new WP_Error('up_to_date', $this->strings['up_to_date']);

		$res = $this->fs_connect( array( ABSPATH, WP_CONTENT_DIR ), $parsed_args['allow_relaxed_file_ownership'] );
		if ( ! $res || is_wp_error( $res ) ) {
			return $res;
		}

		$wp_dir = trailingslashit($wp_filesystem->abspath());

		$partial = true;
		if ( $parsed_args['do_rollback'] )
			$partial = false;
		elseif ( $parsed_args['pre_check_md5'] && ! $this->check_files() )
			$partial = false;

		/*
		 * If partial update is returned from the API, use that, unless we're doing
		 * a reinstall. If we cross the new_bundled version number, then use
		 * the new_bundled zip. Don't though if the constant is set to skip bundled items.
		 * If the API returns a no_content zip, go with it. Finally, default to the full zip.
		 */
		if ( $parsed_args['do_rollback'] && $current->packages->rollback )
			$to_download = 'rollback';
		elseif ( $current->packages->partial && 'reinstall' != $current->response && $wp_version == $current->partial_version && $partial )
			$to_download = 'partial';
		elseif ( $current->packages->new_bundled && version_compare( $wp_version, $current->new_bundled, '<' )
			&& ( ! defined( 'CORE_UPGRADE_SKIP_NEW_BUNDLED' ) || ! CORE_UPGRADE_SKIP_NEW_BUNDLED ) )
			$to_download = 'new_bundled';
		elseif ( $current->packages->no_content )
			$to_download = 'no_content';
		else
			$to_download = 'full';

		// Lock to prevent multiple Core Updates occuring
		$lock = WP_Upgrader::create_lock( 'core_updater', 15 * MINUTE_IN_SECONDS );
		if ( ! $lock ) {
			return new WP_Error( 'locked', $this->strings['locked'] );
		}

		$download = $this->download_package( $current->packages->$to_download );
		if ( is_wp_error( $download ) ) {
			WP_Upgrader::release_lock( 'core_updater' );
			return $download;
		}

		$working_dir = $this->unpack_package( $download );
		if ( is_wp_error( $working_dir ) ) {
			WP_Upgrader::release_lock( 'core_updater' );
			return $working_dir;
		}

		// Copy update-core.php from the new version into place.
		if ( !$wp_filesystem->copy($working_dir . '/wordpress/wp-admin/includes/update-core.php', $wp_dir . 'wp-admin/includes/update-core.php', true) ) {
			$wp_filesystem->delete($working_dir, true);
			WP_Upgrader::release_lock( 'core_updater' );
			return new WP_Error( 'copy_failed_for_update_core_file', __( 'The update cannot be installed because we will be unable to copy some files. This is usually due to inconsistent file permissions.' ), 'wp-admin/includes/update-core.php' );
		}
		$wp_filesystem->chmod($wp_dir . 'wp-admin/includes/update-core.php', FS_CHMOD_FILE);

		require_once( ABSPATH . 'wp-admin/includes/update-core.php' );

		if ( ! function_exists( 'update_core' ) ) {
			WP_Upgrader::release_lock( 'core_updater' );
			return new WP_Error( 'copy_failed_space', $this->strings['copy_failed_space'] );
		}

		$result = update_core( $working_dir, $wp_dir );

		// In the event of an issue, we may be able to roll back.
		if ( $parsed_args['attempt_rollback'] && $current->packages->rollback && ! $parsed_args['do_rollback'] ) {
			$try_rollback = false;
			if ( is_wp_error( $result ) ) {
				$error_code = $result->get_error_code();
				/*
				 * Not all errors are equal. These codes are critical: copy_failed__copy_dir,
				 * mkdir_failed__copy_dir, copy_failed__copy_dir_retry, and disk_full.
				 * do_rollback allows for update_core() to trigger a rollback if needed.
				 */
				if ( false !== strpos( $error_code, 'do_rollback' ) )
					$try_rollback = true;
				elseif ( false !== strpos( $error_code, '__copy_dir' ) )
					$try_rollback = true;
				elseif ( 'disk_full' === $error_code )
					$try_rollback = true;
			}

			if ( $try_rollback ) {
				/** This filter is documented in wp-admin/includes/update-core.php */
				apply_filters( 'update_feedback', $result );

				/** This filter is documented in wp-admin/includes/update-core.php */
				apply_filters( 'update_feedback', $this->strings['start_rollback'] );

				$rollback_result = $this->upgrade( $current, array_merge( $parsed_args, array( 'do_rollback' => true ) ) );

				$original_result = $result;
				$result = new WP_Error( 'rollback_was_required', $this->strings['rollback_was_required'], (object) array( 'update' => $original_result, 'rollback' => $rollback_result ) );
			}
		}

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

		// Clear the current updates
		delete_site_transient( 'update_core' );

		if ( ! $parsed_args['do_rollback'] ) {
			$stats = array(
				'update_type'      => $current->response,
				'success'          => true,
				'fs_method'        => $wp_filesystem->method,
				'fs_method_forced' => defined( 'FS_METHOD' ) || has_filter( 'filesystem_method' ),
				'fs_method_direct' => !empty( $GLOBALS['_wp_filesystem_direct_method'] ) ? $GLOBALS['_wp_filesystem_direct_method'] : '',
				'time_taken'       => time() - $start_time,
				'reported'         => $wp_version,
				'attempted'        => $current->version,
			);

			if ( is_wp_error( $result ) ) {
				$stats['success'] = false;
				// Did a rollback occur?
				if ( ! empty( $try_rollback ) ) {
					$stats['error_code'] = $original_result->get_error_code();
					$stats['error_data'] = $original_result->get_error_data();
					// Was the rollback successful? If not, collect its error too.
					$stats['rollback'] = ! is_wp_error( $rollback_result );
					if ( is_wp_error( $rollback_result ) ) {
						$stats['rollback_code'] = $rollback_result->get_error_code();
						$stats['rollback_data'] = $rollback_result->get_error_data();
					}
				} else {
					$stats['error_code'] = $result->get_error_code();
					$stats['error_data'] = $result->get_error_data();
				}
			}

			wp_version_check( $stats );
		}

		WP_Upgrader::release_lock( 'core_updater' );

		return $result;
	}

	/**
	 * Determines if this WordPress Core version should update to an offered version or not.
	 *
	 * @since 3.7.0
	 * @access public
	 *
	 * @static
	 *
	 * @param string $offered_ver The offered version, of the format x.y.z.
	 * @return bool True if we should update to the offered version, otherwise false.
	 */
	public static function should_update_to_version( $offered_ver ) {
		include( ABSPATH . WPINC . '/version.php' ); // $wp_version; // x.y.z

		$current_branch = implode( '.', array_slice( preg_split( '/[.-]/', $wp_version  ), 0, 2 ) ); // x.y
		$new_branch     = implode( '.', array_slice( preg_split( '/[.-]/', $offered_ver ), 0, 2 ) ); // x.y
		$current_is_development_version = (bool) strpos( $wp_version, '-' );

		// Defaults:
		$upgrade_dev   = true;
		$upgrade_minor = true;
		$upgrade_major = false;

		// WP_AUTO_UPDATE_CORE = true (all), 'minor', false.
		if ( defined( 'WP_AUTO_UPDATE_CORE' ) ) {
			if ( false === WP_AUTO_UPDATE_CORE ) {
				// Defaults to turned off, unless a filter allows it
				$upgrade_dev = $upgrade_minor = $upgrade_major = false;
			} elseif ( true === WP_AUTO_UPDATE_CORE ) {
				// ALL updates for core
				$upgrade_dev = $upgrade_minor = $upgrade_major = true;
			} elseif ( 'minor' === WP_AUTO_UPDATE_CORE ) {
				// Only minor updates for core
				$upgrade_dev = $upgrade_major = false;
				$upgrade_minor = true;
			}
		}

		// 1: If we're already on that version, not much point in updating?
		if ( $offered_ver == $wp_version )
			return false;

		// 2: If we're running a newer version, that's a nope
		if ( version_compare( $wp_version, $offered_ver, '>' ) )
			return false;

		$failure_data = get_site_option( 'auto_core_update_failed' );
		if ( $failure_data ) {
			// If this was a critical update failure, cannot update.
			if ( ! empty( $failure_data['critical'] ) )
				return false;

			// Don't claim we can update on update-core.php if we have a non-critical failure logged.
			if ( $wp_version == $failure_data['current'] && false !== strpos( $offered_ver, '.1.next.minor' ) )
				return false;

			// Cannot update if we're retrying the same A to B update that caused a non-critical failure.
			// Some non-critical failures do allow retries, like download_failed.
			// 3.7.1 => 3.7.2 resulted in files_not_writable, if we are still on 3.7.1 and still trying to update to 3.7.2.
			if ( empty( $failure_data['retry'] ) && $wp_version == $failure_data['current'] && $offered_ver == $failure_data['attempted'] )
				return false;
		}

		// 3: 3.7-alpha-25000 -> 3.7-alpha-25678 -> 3.7-beta1 -> 3.7-beta2
		if ( $current_is_development_version ) {

			/**
			 * Filter whether to enable automatic core updates for development versions.
			 *
			 * @since 3.7.0
			 *
			 * @param bool $upgrade_dev Whether to enable automatic updates for
			 *                          development versions.
			 */
			if ( ! apply_filters( 'allow_dev_auto_core_updates', $upgrade_dev ) )
				return false;
			// Else fall through to minor + major branches below.
		}

		// 4: Minor In-branch updates (3.7.0 -> 3.7.1 -> 3.7.2 -> 3.7.4)
		if ( $current_branch == $new_branch ) {

			/**
			 * Filter whether to enable minor automatic core updates.
			 *
			 * @since 3.7.0
			 *
			 * @param bool $upgrade_minor Whether to enable minor automatic core updates.
			 */
			return apply_filters( 'allow_minor_auto_core_updates', $upgrade_minor );
		}

		// 5: Major version updates (3.7.0 -> 3.8.0 -> 3.9.1)
		if ( version_compare( $new_branch, $current_branch, '>' ) ) {

			/**
			 * Filter whether to enable major automatic core updates.
			 *
			 * @since 3.7.0
			 *
			 * @param bool $upgrade_major Whether to enable major automatic core updates.
			 */
			return apply_filters( 'allow_major_auto_core_updates', $upgrade_major );
		}

		// If we're not sure, we don't want it
		return false;
	}

	/**
	 * Compare the disk file checksums against the expected checksums.
	 *
	 * @since 3.7.0
	 * @access public
	 *
	 * @global string $wp_version
	 * @global string $wp_local_package
	 *
	 * @return bool True if the checksums match, otherwise false.
	 */
	public function check_files() {
		global $wp_version, $wp_local_package;

		$checksums = get_core_checksums( $wp_version, isset( $wp_local_package ) ? $wp_local_package : 'en_US' );

		if ( ! is_array( $checksums ) )
			return false;

		foreach ( $checksums as $file => $checksum ) {
			// Skip files which get updated
			if ( 'wp-content' == substr( $file, 0, 10 ) )
				continue;
			if ( ! file_exists( ABSPATH . $file ) || md5_file( ABSPATH . $file ) !== $checksum )
				return false;
		}

		return true;
	}
}

/**
 * Core class used for handling file uploads.
 *
 * This class handles the upload process and passes it as if it's a local file
 * to the Upgrade/Installer functions.
 *
 * @since 2.8.0
 */
class File_Upload_Upgrader {

	/**
	 * The full path to the file package.
	 *
	 * @since 2.8.0
	 * @access public
	 * @var string $package
	 */
	public $package;

	/**
	 * The name of the file.
	 *
	 * @since 2.8.0
	 * @access public
	 * @var string $filename
	 */
	public $filename;

	/**
	 * The ID of the attachment post for this file.
	 *
	 * @since 3.3.0
	 * @access public
	 * @var int $id
	 */
	public $id = 0;

	/**
	 * Construct the upgrader for a form.
	 *
	 * @since 2.8.0
	 * @access public
	 *
	 * @param string $form      The name of the form the file was uploaded from.
	 * @param string $urlholder The name of the `GET` parameter that holds the filename.
	 */
	public function __construct( $form, $urlholder ) {

		if ( empty($_FILES[$form]['name']) && empty($_GET[$urlholder]) )
			wp_die(__('Please select a file'));

		//Handle a newly uploaded file, Else assume it's already been uploaded
		if ( ! empty($_FILES) ) {
			$overrides = array( 'test_form' => false, 'test_type' => false );
			$file = wp_handle_upload( $_FILES[$form], $overrides );

			if ( isset( $file['error'] ) )
				wp_die( $file['error'] );

			$this->filename = $_FILES[$form]['name'];
			$this->package = $file['file'];

			// Construct the object array
			$object = array(
				'post_title' => $this->filename,
				'post_content' => $file['url'],
				'post_mime_type' => $file['type'],
				'guid' => $file['url'],
				'context' => 'upgrader',
				'post_status' => 'private'
			);

			// Save the data.
			$this->id = wp_insert_attachment( $object, $file['file'] );

			// Schedule a cleanup for 2 hours from now in case of failed install.
			wp_schedule_single_event( time() + 2 * HOUR_IN_SECONDS, 'upgrader_scheduled_cleanup', array( $this->id ) );

		} elseif ( is_numeric( $_GET[$urlholder] ) ) {
			// Numeric Package = previously uploaded file, see above.
			$this->id = (int) $_GET[$urlholder];
			$attachment = get_post( $this->id );
			if ( empty($attachment) )
				wp_die(__('Please select a file'));

			$this->filename = $attachment->post_title;
			$this->package = get_attached_file( $attachment->ID );
		} else {
			// Else, It's set to something, Back compat for plugins using the old (pre-3.3) File_Uploader handler.
			if ( ! ( ( $uploads = wp_upload_dir() ) && false === $uploads['error'] ) )
				wp_die( $uploads['error'] );

			$this->filename = $_GET[$urlholder];
			$this->package = $uploads['basedir'] . '/' . $this->filename;
		}
	}

	/**
	 * Delete the attachment/uploaded file.
	 *
	 * @since 3.2.2
	 * @access public
	 *
	 * @return bool Whether the cleanup was successful.
	 */
	public function cleanup() {
		if ( $this->id )
			wp_delete_attachment( $this->id );

		elseif ( file_exists( $this->package ) )
			return @unlink( $this->package );

		return true;
	}
}

/**
 * Core class used for handling automatic background updates.
 *
 * @since 3.7.0
 */
class WP_Automatic_Updater {

	/**
	 * Tracks update results during processing.
	 *
	 * @var array
	 * @access protected
	 */
	protected $update_results = array();

	/**
	 * Whether the entire automatic updater is disabled.
	 *
	 * @since 3.7.0
	 * @access public
	 */
	public function is_disabled() {
		// Background updates are disabled if you don't want file changes.
		if ( defined( 'DISALLOW_FILE_MODS' ) && DISALLOW_FILE_MODS )
			return true;

		if ( wp_installing() )
			return true;

		// More fine grained control can be done through the WP_AUTO_UPDATE_CORE constant and filters.
		$disabled = defined( 'AUTOMATIC_UPDATER_DISABLED' ) && AUTOMATIC_UPDATER_DISABLED;

		/**
		 * Filter whether to entirely disable background updates.
		 *
		 * There are more fine-grained filters and controls for selective disabling.
		 * This filter parallels the AUTOMATIC_UPDATER_DISABLED constant in name.
		 *
		 * This also disables update notification emails. That may change in the future.
		 *
		 * @since 3.7.0
		 *
		 * @param bool $disabled Whether the updater should be disabled.
		 */
		return apply_filters( 'automatic_updater_disabled', $disabled );
	}

	/**
	 * Check for version control checkouts.
	 *
	 * Checks for Subversion, Git, Mercurial, and Bazaar. It recursively looks up the
	 * filesystem to the top of the drive, erring on the side of detecting a VCS
	 * checkout somewhere.
	 *
	 * ABSPATH is always checked in addition to whatever $context is (which may be the
	 * wp-content directory, for example). The underlying assumption is that if you are
	 * using version control *anywhere*, then you should be making decisions for
	 * how things get updated.
	 *
	 * @since 3.7.0
	 * @access public
	 *
	 * @param string $context The filesystem path to check, in addition to ABSPATH.
	 */
	public function is_vcs_checkout( $context ) {
		$context_dirs = array( untrailingslashit( $context ) );
		if ( $context !== ABSPATH )
			$context_dirs[] = untrailingslashit( ABSPATH );

		$vcs_dirs = array( '.svn', '.git', '.hg', '.bzr' );
		$check_dirs = array();

		foreach ( $context_dirs as $context_dir ) {
			// Walk up from $context_dir to the root.
			do {
				$check_dirs[] = $context_dir;

				// Once we've hit '/' or 'C:\', we need to stop. dirname will keep returning the input here.
				if ( $context_dir == dirname( $context_dir ) )
					break;

			// Continue one level at a time.
			} while ( $context_dir = dirname( $context_dir ) );
		}

		$check_dirs = array_unique( $check_dirs );

		// Search all directories we've found for evidence of version control.
		foreach ( $vcs_dirs as $vcs_dir ) {
			foreach ( $check_dirs as $check_dir ) {
				if ( $checkout = @is_dir( rtrim( $check_dir, '\\/' ) . "/$vcs_dir" ) )
					break 2;
			}
		}

		/**
		 * Filter whether the automatic updater should consider a filesystem
		 * location to be potentially managed by a version control system.
		 *
		 * @since 3.7.0
		 *
		 * @param bool $checkout  Whether a VCS checkout was discovered at $context
		 *                        or ABSPATH, or anywhere higher.
		 * @param string $context The filesystem context (a path) against which
		 *                        filesystem status should be checked.
		 */
		return apply_filters( 'automatic_updates_is_vcs_checkout', $checkout, $context );
	}

	/**
	 * Tests to see if we can and should update a specific item.
	 *
	 * @since 3.7.0
	 * @access public
	 *
	 * @global wpdb $wpdb WordPress database abstraction object.
	 *
	 * @param string $type    The type of update being checked: 'core', 'theme',
	 *                        'plugin', 'translation'.
	 * @param object $item    The update offer.
	 * @param string $context The filesystem context (a path) against which filesystem
	 *                        access and status should be checked.
	 */
	public function should_update( $type, $item, $context ) {
		// Used to see if WP_Filesystem is set up to allow unattended updates.
		$skin = new Automatic_Upgrader_Skin;

		if ( $this->is_disabled() )
			return false;

		// Only relax the filesystem checks when the update doesn't include new files
		$allow_relaxed_file_ownership = false;
		if ( 'core' == $type && isset( $item->new_files ) && ! $item->new_files ) {
			$allow_relaxed_file_ownership = true;
		}

		// If we can't do an auto core update, we may still be able to email the user.
		if ( ! $skin->request_filesystem_credentials( false, $context, $allow_relaxed_file_ownership ) || $this->is_vcs_checkout( $context ) ) {
			if ( 'core' == $type )
				$this->send_core_update_notification_email( $item );
			return false;
		}

		// Next up, is this an item we can update?
		if ( 'core' == $type )
			$update = Core_Upgrader::should_update_to_version( $item->current );
		else
			$update = ! empty( $item->autoupdate );

		/**
		 * Filter whether to automatically update core, a plugin, a theme, or a language.
		 *
		 * The dynamic portion of the hook name, `$type`, refers to the type of update
		 * being checked. Can be 'core', 'theme', 'plugin', or 'translation'.
		 *
		 * Generally speaking, plugins, themes, and major core versions are not updated
		 * by default, while translations and minor and development versions for core
		 * are updated by default.
		 *
		 * See the {@see 'allow_dev_auto_core_updates', {@see 'allow_minor_auto_core_updates'},
		 * and {@see 'allow_major_auto_core_updates'} filters for a more straightforward way to
		 * adjust core updates.
		 *
		 * @since 3.7.0
		 *
		 * @param bool   $update Whether to update.
		 * @param object $item   The update offer.
		 */
		$update = apply_filters( 'auto_update_' . $type, $update, $item );

		if ( ! $update ) {
			if ( 'core' == $type )
				$this->send_core_update_notification_email( $item );
			return false;
		}

		// If it's a core update, are we actually compatible with its requirements?
		if ( 'core' == $type ) {
			global $wpdb;

			$php_compat = version_compare( phpversion(), $item->php_version, '>=' );
			if ( file_exists( WP_CONTENT_DIR . '/db.php' ) && empty( $wpdb->is_mysql ) )
				$mysql_compat = true;
			else
				$mysql_compat = version_compare( $wpdb->db_version(), $item->mysql_version, '>=' );

			if ( ! $php_compat || ! $mysql_compat )
				return false;
		}

		return true;
	}

	/**
	 * Notifies an administrator of a core update.
	 *
	 * @since 3.7.0
	 * @access protected
	 *
	 * @param object $item The update offer.
	 */
	protected function send_core_update_notification_email( $item ) {
		$notified = get_site_option( 'auto_core_update_notified' );

		// Don't notify if we've already notified the same email address of the same version.
		if ( $notified && $notified['email'] == get_site_option( 'admin_email' ) && $notified['version'] == $item->current )
			return false;

		// See if we need to notify users of a core update.
		$notify = ! empty( $item->notify_email );

		/**
		 * Filter whether to notify the site administrator of a new core update.
		 *
		 * By default, administrators are notified when the update offer received
		 * from WordPress.org sets a particular flag. This allows some discretion
		 * in if and when to notify.
		 *
		 * This filter is only evaluated once per release. If the same email address
		 * was already notified of the same new version, WordPress won't repeatedly
		 * email the administrator.
		 *
		 * This filter is also used on about.php to check if a plugin has disabled
		 * these notifications.
		 *
		 * @since 3.7.0
		 *
		 * @param bool   $notify Whether the site administrator is notified.
		 * @param object $item   The update offer.
		 */
		if ( ! apply_filters( 'send_core_update_notification_email', $notify, $item ) )
			return false;

		$this->send_email( 'manual', $item );
		return true;
	}

	/**
	 * Update an item, if appropriate.
	 *
	 * @since 3.7.0
	 * @access public
	 *
	 * @param string $type The type of update being checked: 'core', 'theme', 'plugin', 'translation'.
	 * @param object $item The update offer.
	 *
	 * @return null|WP_Error
	 */
	public function update( $type, $item ) {
		$skin = new Automatic_Upgrader_Skin;

		switch ( $type ) {
			case 'core':
				// The Core upgrader doesn't use the Upgrader's skin during the actual main part of the upgrade, instead, firing a filter.
				add_filter( 'update_feedback', array( $skin, 'feedback' ) );
				$upgrader = new Core_Upgrader( $skin );
				$context  = ABSPATH;
				break;
			case 'plugin':
				$upgrader = new Plugin_Upgrader( $skin );
				$context  = WP_PLUGIN_DIR; // We don't support custom Plugin directories, or updates for WPMU_PLUGIN_DIR
				break;
			case 'theme':
				$upgrader = new Theme_Upgrader( $skin );
				$context  = get_theme_root( $item->theme );
				break;
			case 'translation':
				$upgrader = new Language_Pack_Upgrader( $skin );
				$context  = WP_CONTENT_DIR; // WP_LANG_DIR;
				break;
		}

		// Determine whether we can and should perform this update.
		if ( ! $this->should_update( $type, $item, $context ) )
			return false;

		/**
		 * Fires immediately prior to an auto-update.
		 *
		 * @since 4.4.0
		 *
		 * @param string $type    The type of update being checked: 'core', 'theme', 'plugin', or 'translation'.
		 * @param object $item    The update offer.
		 * @param string $context The filesystem context (a path) against which filesystem access and status
		 *                        should be checked.
		 */
		do_action( 'pre_auto_update', $type, $item, $context );

		$upgrader_item = $item;
		switch ( $type ) {
			case 'core':
				$skin->feedback( __( 'Updating to WordPress %s' ), $item->version );
				$item_name = sprintf( __( 'WordPress %s' ), $item->version );
				break;
			case 'theme':
				$upgrader_item = $item->theme;
				$theme = wp_get_theme( $upgrader_item );
				$item_name = $theme->Get( 'Name' );
				$skin->feedback( __( 'Updating theme: %s' ), $item_name );
				break;
			case 'plugin':
				$upgrader_item = $item->plugin;
				$plugin_data = get_plugin_data( $context . '/' . $upgrader_item );
				$item_name = $plugin_data['Name'];
				$skin->feedback( __( 'Updating plugin: %s' ), $item_name );
				break;
			case 'translation':
				$language_item_name = $upgrader->get_name_for_update( $item );
				$item_name = sprintf( __( 'Translations for %s' ), $language_item_name );
				$skin->feedback( sprintf( __( 'Updating translations for %1$s (%2$s)&#8230;' ), $language_item_name, $item->language ) );
				break;
		}

		$allow_relaxed_file_ownership = false;
		if ( 'core' == $type && isset( $item->new_files ) && ! $item->new_files ) {
			$allow_relaxed_file_ownership = true;
		}

		// Boom, This sites about to get a whole new splash of paint!
		$upgrade_result = $upgrader->upgrade( $upgrader_item, array(
			'clear_update_cache' => false,
			// Always use partial builds if possible for core updates.
			'pre_check_md5'      => false,
			// Only available for core updates.
			'attempt_rollback'   => true,
			// Allow relaxed file ownership in some scenarios
			'allow_relaxed_file_ownership' => $allow_relaxed_file_ownership,
		) );

		// If the filesystem is unavailable, false is returned.
		if ( false === $upgrade_result ) {
			$upgrade_result = new WP_Error( 'fs_unavailable', __( 'Could not access filesystem.' ) );
		}

		if ( 'core' == $type ) {
			if ( is_wp_error( $upgrade_result ) && ( 'up_to_date' == $upgrade_result->get_error_code() || 'locked' == $upgrade_result->get_error_code() ) ) {
				// These aren't actual errors, treat it as a skipped-update instead to avoid triggering the post-core update failure routines.
				return false;
			}

			// Core doesn't output this, so let's append it so we don't get confused.
			if ( is_wp_error( $upgrade_result ) ) {
				$skin->error( __( 'Installation Failed' ), $upgrade_result );
			} else {
				$skin->feedback( __( 'WordPress updated successfully' ) );
			}
		}

		$this->update_results[ $type ][] = (object) array(
			'item'     => $item,
			'result'   => $upgrade_result,
			'name'     => $item_name,
			'messages' => $skin->get_upgrade_messages()
		);

		return $upgrade_result;
	}

	/**
	 * Kicks off the background update process, looping through all pending updates.
	 *
	 * @since 3.7.0
	 * @access public
	 *
	 * @global wpdb   $wpdb
	 * @global string $wp_version
	 */
	public function run() {
		global $wpdb, $wp_version;

		if ( $this->is_disabled() )
			return;

		if ( ! is_main_network() || ! is_main_site() )
			return;

		if ( ! WP_Upgrader::create_lock( 'auto_updater' ) )
			return;

		// Don't automatically run these thins, as we'll handle it ourselves
		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' );

		// Next, Plugins
		wp_update_plugins(); // Check for Plugin updates
		$plugin_updates = get_site_transient( 'update_plugins' );
		if ( $plugin_updates && !empty( $plugin_updates->response ) ) {
			foreach ( $plugin_updates->response as $plugin ) {
				$this->update( 'plugin', $plugin );
			}
			// Force refresh of plugin update information
			wp_clean_plugins_cache();
		}

		// Next, those themes we all love
		wp_update_themes();  // Check for Theme updates
		$theme_updates = get_site_transient( 'update_themes' );
		if ( $theme_updates && !empty( $theme_updates->response ) ) {
			foreach ( $theme_updates->response as $theme ) {
				$this->update( 'theme', (object) $theme );
			}
			// Force refresh of theme update information
			wp_clean_themes_cache();
		}

		// Next, Process any core update
		wp_version_check(); // Check for Core updates
		$core_update = find_core_auto_update();

		if ( $core_update )
			$this->update( 'core', $core_update );

		// Clean up, and check for any pending translations
		// (Core_Upgrader checks for core updates)
		$theme_stats = array();
		if ( isset( $this->update_results['theme'] ) ) {
			foreach ( $this->update_results['theme'] as $upgrade ) {
				$theme_stats[ $upgrade->item->theme ] = ( true === $upgrade->result );
			}
		}
		wp_update_themes( $theme_stats );  // Check for Theme updates

		$plugin_stats = array();
		if ( isset( $this->update_results['plugin'] ) ) {
			foreach ( $this->update_results['plugin'] as $upgrade ) {
				$plugin_stats[ $upgrade->item->plugin ] = ( true === $upgrade->result );
			}
		}
		wp_update_plugins( $plugin_stats ); // Check for Plugin updates

		// Finally, Process any new translations
		$language_updates = wp_get_translation_updates();
		if ( $language_updates ) {
			foreach ( $language_updates as $update ) {
				$this->update( 'translation', $update );
			}

			// Clear existing caches
			wp_clean_update_cache();

			wp_version_check();  // check for Core updates
			wp_update_themes();  // Check for Theme updates
			wp_update_plugins(); // Check for Plugin updates
		}

		// Send debugging email to all development installs.
		if ( ! empty( $this->update_results ) ) {
			$development_version = false !== strpos( $wp_version, '-' );

			/**
			 * Filter whether to send a debugging email for each automatic background update.
			 *
			 * @since 3.7.0
			 *
			 * @param bool $development_version By default, emails are sent if the
			 *                                  install is a development version.
			 *                                  Return false to avoid the email.
			 */
			if ( apply_filters( 'automatic_updates_send_debug_email', $development_version ) )
				$this->send_debug_email();

			if ( ! empty( $this->update_results['core'] ) )
				$this->after_core_update( $this->update_results['core'][0] );

			/**
			 * Fires after all automatic updates have run.
			 *
			 * @since 3.8.0
			 *
			 * @param array $update_results The results of all attempted updates.
			 */
			do_action( 'automatic_updates_complete', $this->update_results );
		}

		WP_Upgrader::release_lock( 'auto_updater' );
	}

	/**
	 * If we tried to perform a core update, check if we should send an email,
	 * and if we need to avoid processing future updates.
	 *
	 * @since Unknown
	 * @access protected
	 *
	 * @global string $wp_version
	 *
	 * @param object $update_result The result of the core update. Includes the update offer and result.
	 */
	protected function after_core_update( $update_result ) {
		global $wp_version;

		$core_update = $update_result->item;
		$result      = $update_result->result;

		if ( ! is_wp_error( $result ) ) {
			$this->send_email( 'success', $core_update );
			return;
		}

		$error_code = $result->get_error_code();

		// Any of these WP_Error codes are critical failures, as in they occurred after we started to copy core files.
		// We should not try to perform a background update again until there is a successful one-click update performed by the user.
		$critical = false;
		if ( $error_code === 'disk_full' || false !== strpos( $error_code, '__copy_dir' ) ) {
			$critical = true;
		} elseif ( $error_code === 'rollback_was_required' && is_wp_error( $result->get_error_data()->rollback ) ) {
			// A rollback is only critical if it failed too.
			$critical = true;
			$rollback_result = $result->get_error_data()->rollback;
		} elseif ( false !== strpos( $error_code, 'do_rollback' ) ) {
			$critical = true;
		}

		if ( $critical ) {
			$critical_data = array(
				'attempted'  => $core_update->current,
				'current'    => $wp_version,
				'error_code' => $error_code,
				'error_data' => $result->get_error_data(),
				'timestamp'  => time(),
				'critical'   => true,
			);
			if ( isset( $rollback_result ) ) {
				$critical_data['rollback_code'] = $rollback_result->get_error_code();
				$critical_data['rollback_data'] = $rollback_result->get_error_data();
			}
			update_site_option( 'auto_core_update_failed', $critical_data );
			$this->send_email( 'critical', $core_update, $result );
			return;
		}

		/*
		 * Any other WP_Error code (like download_failed or files_not_writable) occurs before
		 * we tried to copy over core files. Thus, the failures are early and graceful.
		 *
		 * We should avoid trying to perform a background update again for the same version.
		 * But we can try again if another version is released.
		 *
		 * For certain 'transient' failures, like download_failed, we should allow retries.
		 * In fact, let's schedule a special update for an hour from now. (It's possible
		 * the issue could actually be on WordPress.org's side.) If that one fails, then email.
		 */
		$send = true;
  		$transient_failures = array( 'incompatible_archive', 'download_failed', 'insane_distro', 'locked' );
  		if ( in_array( $error_code, $transient_failures ) && ! get_site_option( 'auto_core_update_failed' ) ) {
  			wp_schedule_single_event( time() + HOUR_IN_SECONDS, 'wp_maybe_auto_update' );
  			$send = false;
  		}

  		$n = get_site_option( 'auto_core_update_notified' );
		// Don't notify if we've already notified the same email address of the same version of the same notification type.
		if ( $n && 'fail' == $n['type'] && $n['email'] == get_site_option( 'admin_email' ) && $n['version'] == $core_update->current )
			$send = false;

		update_site_option( 'auto_core_update_failed', array(
			'attempted'  => $core_update->current,
			'current'    => $wp_version,
			'error_code' => $error_code,
			'error_data' => $result->get_error_data(),
			'timestamp'  => time(),
			'retry'      => in_array( $error_code, $transient_failures ),
		) );

		if ( $send )
			$this->send_email( 'fail', $core_update, $result );
	}

	/**
	 * Sends an email upon the completion or failure of a background core update.
	 *
	 * @since 3.7.0
	 * @access protected
	 *
	 * @global string $wp_version
	 *
	 * @param string $type        The type of email to send. Can be one of 'success', 'fail', 'manual', 'critical'.
	 * @param object $core_update The update offer that was attempted.
	 * @param mixed  $result      Optional. The result for the core update. Can be WP_Error.
	 */
	protected function send_email( $type, $core_update, $result = null ) {
		update_site_option( 'auto_core_update_notified', array(
			'type'      => $type,
			'email'     => get_site_option( 'admin_email' ),
			'version'   => $core_update->current,
			'timestamp' => time(),
		) );

		$next_user_core_update = get_preferred_from_update_core();
		// If the update transient is empty, use the update we just performed
		if ( ! $next_user_core_update )
			$next_user_core_update = $core_update;
		$newer_version_available = ( 'upgrade' == $next_user_core_update->response && version_compare( $next_user_core_update->version, $core_update->version, '>' ) );

		/**
		 * Filter whether to send an email following an automatic background core update.
		 *
		 * @since 3.7.0
		 *
		 * @param bool   $send        Whether to send the email. Default true.
		 * @param string $type        The type of email to send. Can be one of
		 *                            'success', 'fail', 'critical'.
		 * @param object $core_update The update offer that was attempted.
		 * @param mixed  $result      The result for the core update. Can be WP_Error.
		 */
		if ( 'manual' !== $type && ! apply_filters( 'auto_core_update_send_email', true, $type, $core_update, $result ) )
			return;

		switch ( $type ) {
			case 'success' : // We updated.
				/* translators: 1: Site name, 2: WordPress version number. */
				$subject = __( '[%1$s] Your site has updated to WordPress %2$s' );
				break;

			case 'fail' :   // We tried to update but couldn't.
			case 'manual' : // We can't update (and made no attempt).
				/* translators: 1: Site name, 2: WordPress version number. */
				$subject = __( '[%1$s] WordPress %2$s is available. Please update!' );
				break;

			case 'critical' : // We tried to update, started to copy files, then things went wrong.
				/* translators: 1: Site name. */
				$subject = __( '[%1$s] URGENT: Your site may be down due to a failed update' );
				break;

			default :
				return;
		}

		// If the auto update is not to the latest version, say that the current version of WP is available instead.
		$version = 'success' === $type ? $core_update->current : $next_user_core_update->current;
		$subject = sprintf( $subject, wp_specialchars_decode( get_option( 'blogname' ), ENT_QUOTES ), $version );

		$body = '';

		switch ( $type ) {
			case 'success' :
				$body .= sprintf( __( 'Howdy! Your site at %1$s has been updated automatically to WordPress %2$s.' ), home_url(), $core_update->current );
				$body .= "\n\n";
				if ( ! $newer_version_available )
					$body .= __( 'No further action is needed on your part.' ) . ' ';

				// Can only reference the About screen if their update was successful.
				list( $about_version ) = explode( '-', $core_update->current, 2 );
				$body .= sprintf( __( "For more on version %s, see the About WordPress screen:" ), $about_version );
				$body .= "\n" . admin_url( 'about.php' );

				if ( $newer_version_available ) {
					$body .= "\n\n" . sprintf( __( 'WordPress %s is also now available.' ), $next_user_core_update->current ) . ' ';
					$body .= __( 'Updating is easy and only takes a few moments:' );
					$body .= "\n" . network_admin_url( 'update-core.php' );
				}

				break;

			case 'fail' :
			case 'manual' :
				$body .= sprintf( __( 'Please update your site at %1$s to WordPress %2$s.' ), home_url(), $next_user_core_update->current );

				$body .= "\n\n";

				// Don't show this message if there is a newer version available.
				// Potential for confusion, and also not useful for them to know at this point.
				if ( 'fail' == $type && ! $newer_version_available )
					$body .= __( 'We tried but were unable to update your site automatically.' ) . ' ';

				$body .= __( 'Updating is easy and only takes a few moments:' );
				$body .= "\n" . network_admin_url( 'update-core.php' );
				break;

			case 'critical' :
				if ( $newer_version_available )
					$body .= sprintf( __( 'Your site at %1$s experienced a critical failure while trying to update WordPress to version %2$s.' ), home_url(), $core_update->current );
				else
					$body .= sprintf( __( 'Your site at %1$s experienced a critical failure while trying to update to the latest version of WordPress, %2$s.' ), home_url(), $core_update->current );

				$body .= "\n\n" . __( "This means your site may be offline or broken. Don't panic; this can be fixed." );

				$body .= "\n\n" . __( "Please check out your site now. It's possible that everything is working. If it says you need to update, you should do so:" );
				$body .= "\n" . network_admin_url( 'update-core.php' );
				break;
		}

		$critical_support = 'critical' === $type && ! empty( $core_update->support_email );
		if ( $critical_support ) {
			// Support offer if available.
			$body .= "\n\n" . sprintf( __( "The WordPress team is willing to help you. Forward this email to %s and the team will work with you to make sure your site is working." ), $core_update->support_email );
		} else {
			// Add a note about the support forums.
			$body .= "\n\n" . __( 'If you experience any issues or need support, the volunteers in the WordPress.org support forums may be able to help.' );
			$body .= "\n" . __( 'https://wordpress.org/support/' );
		}

		// Updates are important!
		if ( $type != 'success' || $newer_version_available ) {
			$body .= "\n\n" . __( 'Keeping your site updated is important for security. It also makes the internet a safer place for you and your readers.' );
		}

		if ( $critical_support ) {
			$body .= " " . __( "If you reach out to us, we'll also ensure you'll never have this problem again." );
		}

		// If things are successful and we're now on the latest, mention plugins and themes if any are out of date.
		if ( $type == 'success' && ! $newer_version_available && ( get_plugin_updates() || get_theme_updates() ) ) {
			$body .= "\n\n" . __( 'You also have some plugins or themes with updates available. Update them now:' );
			$body .= "\n" . network_admin_url();
		}

		$body .= "\n\n" . __( 'The WordPress Team' ) . "\n";

		if ( 'critical' == $type && is_wp_error( $result ) ) {
			$body .= "\n***\n\n";
			$body .= sprintf( __( 'Your site was running version %s.' ), $GLOBALS['wp_version'] );
			$body .= ' ' . __( 'We have some data that describes the error your site encountered.' );
			$body .= ' ' . __( 'Your hosting company, support forum volunteers, or a friendly developer may be able to use this information to help you:' );

			// If we had a rollback and we're still critical, then the rollback failed too.
			// Loop through all errors (the main WP_Error, the update result, the rollback result) for code, data, etc.
			if ( 'rollback_was_required' == $result->get_error_code() )
				$errors = array( $result, $result->get_error_data()->update, $result->get_error_data()->rollback );
			else
				$errors = array( $result );

			foreach ( $errors as $error ) {
				if ( ! is_wp_error( $error ) )
					continue;
				$error_code = $error->get_error_code();
				$body .= "\n\n" . sprintf( __( "Error code: %s" ), $error_code );
				if ( 'rollback_was_required' == $error_code )
					continue;
				if ( $error->get_error_message() )
					$body .= "\n" . $error->get_error_message();
				$error_data = $error->get_error_data();
				if ( $error_data )
					$body .= "\n" . implode( ', ', (array) $error_data );
			}
			$body .= "\n";
		}

		$to  = get_site_option( 'admin_email' );
		$headers = '';

		$email = compact( 'to', 'subject', 'body', 'headers' );

		/**
		 * Filter the email sent following an automatic background core update.
		 *
		 * @since 3.7.0
		 *
		 * @param array $email {
		 *     Array of email arguments that will be passed to wp_mail().
		 *
		 *     @type string $to      The email recipient. An array of emails
		 *                            can be returned, as handled by wp_mail().
		 *     @type string $subject The email's subject.
		 *     @type string $body    The email message body.
		 *     @type string $headers Any email headers, defaults to no headers.
		 * }
		 * @param string $type        The type of email being sent. Can be one of
		 *                            'success', 'fail', 'manual', 'critical'.
		 * @param object $core_update The update offer that was attempted.
		 * @param mixed  $result      The result for the core update. Can be WP_Error.
		 */
		$email = apply_filters( 'auto_core_update_email', $email, $type, $core_update, $result );

		wp_mail( $email['to'], wp_specialchars_decode( $email['subject'] ), $email['body'], $email['headers'] );
	}

	/**
	 * Prepares and sends an email of a full log of background update results, useful for debugging and geekery.
	 *
	 * @since 3.7.0
	 * @access protected
	 */
	protected function send_debug_email() {
		$update_count = 0;
		foreach ( $this->update_results as $type => $updates )
			$update_count += count( $updates );

		$body = array();
		$failures = 0;

		$body[] = sprintf( __( 'WordPress site: %s' ), network_home_url( '/' ) );

		// Core
		if ( isset( $this->update_results['core'] ) ) {
			$result = $this->update_results['core'][0];
			if ( $result->result && ! is_wp_error( $result->result ) ) {
				$body[] = sprintf( __( 'SUCCESS: WordPress was successfully updated to %s' ), $result->name );
			} else {
				$body[] = sprintf( __( 'FAILED: WordPress failed to update to %s' ), $result->name );
				$failures++;
			}
			$body[] = '';
		}

		// Plugins, Themes, Translations
		foreach ( array( 'plugin', 'theme', 'translation' ) as $type ) {
			if ( ! isset( $this->update_results[ $type ] ) )
				continue;
			$success_items = wp_list_filter( $this->update_results[ $type ], array( 'result' => true ) );
			if ( $success_items ) {
				$messages = array(
					'plugin'      => __( 'The following plugins were successfully updated:' ),
					'theme'       => __( 'The following themes were successfully updated:' ),
					'translation' => __( 'The following translations were successfully updated:' ),
				);

				$body[] = $messages[ $type ];
				foreach ( wp_list_pluck( $success_items, 'name' ) as $name ) {
					$body[] = ' * ' . sprintf( __( 'SUCCESS: %s' ), $name );
				}
			}
			if ( $success_items != $this->update_results[ $type ] ) {
				// Failed updates
				$messages = array(
					'plugin'      => __( 'The following plugins failed to update:' ),
					'theme'       => __( 'The following themes failed to update:' ),
					'translation' => __( 'The following translations failed to update:' ),
				);

				$body[] = $messages[ $type ];
				foreach ( $this->update_results[ $type ] as $item ) {
					if ( ! $item->result || is_wp_error( $item->result ) ) {
						$body[] = ' * ' . sprintf( __( 'FAILED: %s' ), $item->name );
						$failures++;
					}
				}
			}
			$body[] = '';
		}

		$site_title = wp_specialchars_decode( get_bloginfo( 'name' ), ENT_QUOTES );
		if ( $failures ) {
			$body[] = trim( __(
"BETA TESTING?
=============

This debugging email is sent when you are using a development version of WordPress.

If you think these failures might be due to a bug in WordPress, could you report it?
 * Open a thread in the support forums: https://wordpress.org/support/forum/alphabeta
 * Or, if you're comfortable writing a bug report: https://core.trac.wordpress.org/

Thanks! -- The WordPress Team" ) );
			$body[] = '';

			$subject = sprintf( __( '[%s] There were failures during background updates' ), $site_title );
		} else {
			$subject = sprintf( __( '[%s] Background updates have finished' ), $site_title );
		}

		$body[] = trim( __(
'UPDATE LOG
==========' ) );
		$body[] = '';

		foreach ( array( 'core', 'plugin', 'theme', 'translation' ) as $type ) {
			if ( ! isset( $this->update_results[ $type ] ) )
				continue;
			foreach ( $this->update_results[ $type ] as $update ) {
				$body[] = $update->name;
				$body[] = str_repeat( '-', strlen( $update->name ) );
				foreach ( $update->messages as $message )
					$body[] = "  " . html_entity_decode( str_replace( '&#8230;', '...', $message ) );
				if ( is_wp_error( $update->result ) ) {
					$results = array( 'update' => $update->result );
					// If we rolled back, we want to know an error that occurred then too.
					if ( 'rollback_was_required' === $update->result->get_error_code() )
						$results = (array) $update->result->get_error_data();
					foreach ( $results as $result_type => $result ) {
						if ( ! is_wp_error( $result ) )
							continue;

						if ( 'rollback' === $result_type ) {
							/* translators: 1: Error code, 2: Error message. */
							$body[] = '  ' . sprintf( __( 'Rollback Error: [%1$s] %2$s' ), $result->get_error_code(), $result->get_error_message() );
						} else {
							/* translators: 1: Error code, 2: Error message. */
							$body[] = '  ' . sprintf( __( 'Error: [%1$s] %2$s' ), $result->get_error_code(), $result->get_error_message() );
						}

						if ( $result->get_error_data() )
							$body[] = '         ' . implode( ', ', (array) $result->get_error_data() );
					}
				}
				$body[] = '';
			}
		}

		$email = array(
			'to'      => get_site_option( 'admin_email' ),
			'subject' => $subject,
			'body'    => implode( "\n", $body ),
			'headers' => ''
		);

		/**
		 * Filter the debug email that can be sent following an automatic
		 * background core update.
		 *
		 * @since 3.8.0
		 *
		 * @param array $email {
		 *     Array of email arguments that will be passed to wp_mail().
		 *
		 *     @type string $to      The email recipient. An array of emails
		 *                           can be returned, as handled by wp_mail().
		 *     @type string $subject Email subject.
		 *     @type string $body    Email message body.
		 *     @type string $headers Any email headers. Default empty.
		 * }
		 * @param int   $failures The number of failures encountered while upgrading.
		 * @param mixed $results  The results of all attempted updates.
		 */
		$email = apply_filters( 'automatic_updates_debug_email', $email, $failures, $this->update_results );

		wp_mail( $email['to'], wp_specialchars_decode( $email['subject'] ), $email['body'], $email['headers'] );
	}
}
