<?php

/**

 * Upgrade API: Core_Upgrader class

 *

 * @package WordPress

 * @subpackage Upgrader

 * @since 4.6.0

 */

/**

 * 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

 * @since 4.6.0 Moved to its own file from wp-admin/includes/class-wp-upgrader.php.

 *

 * @see WP_Upgrader

 */

class Core_Upgrader extends WP_Upgrader {

	/**

	 * Initialize the upgrade strings.

	 *

	 * @since 2.8.0

	 */

	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.');

		/* translators: %s: package URL */

		$this->strings['downloading_package'] = sprintf( __( 'Downloading update from %s&#8230;' ), '<span class="code">%s</span>' );

		$this->strings['unpack_package'] = __('Unpacking the update…');

		$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

	 *

	 * @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 reinstallation. 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 occurring

		$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

	 *

	 * @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 ) {

			/**

			 * Filters 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 ) {

			/**

			 * Filters 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, '>' ) ) {

			/**

			 * Filters 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

	 *

	 * @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;

	}

}