Source

File: wp-admin/includes/file.php

function _unzip_file_pclzip( $file, $to, $needed_dirs = array() ) {
	global $wp_filesystem;

	mbstring_binary_safe_encoding();

	require_once ABSPATH . 'wp-admin/includes/class-pclzip.php';

	$archive = new PclZip( $file );

	$archive_files = $archive->extract( PCLZIP_OPT_EXTRACT_AS_STRING );

	reset_mbstring_encoding();

	// Is the archive valid?
	if ( ! is_array( $archive_files ) ) {
		return new WP_Error( 'incompatible_archive', __( 'Incompatible Archive.' ), $archive->errorInfo( true ) );
	}

	if ( 0 === count( $archive_files ) ) {
		return new WP_Error( 'empty_archive_pclzip', __( 'Empty archive.' ) );
	}

	$uncompressed_size = 0;

	// Determine any children directories needed (From within the archive).
	foreach ( $archive_files as $file ) {
		if ( '__MACOSX/' === substr( $file['filename'], 0, 9 ) ) { // Skip the OS X-created __MACOSX directory.
			continue;
		}

		$uncompressed_size += $file['size'];

		$needed_dirs[] = $to . untrailingslashit( $file['folder'] ? $file['filename'] : dirname( $file['filename'] ) );
	}

	/*
	 * disk_free_space() could return false. Assume that any falsey value is an error.
	 * A disk that has zero free bytes has bigger problems.
	 * Require we have enough space to unzip the file and copy its contents, with a 10% buffer.
	 */
	if ( wp_doing_cron() ) {
		$available_space = @disk_free_space( WP_CONTENT_DIR );
		if ( $available_space && ( $uncompressed_size * 2.1 ) > $available_space ) {
			return new WP_Error( 'disk_full_unzip_file', __( 'Could not copy files. You may have run out of disk space.' ), compact( 'uncompressed_size', 'available_space' ) );
		}
	}

	$needed_dirs = array_unique( $needed_dirs );
	foreach ( $needed_dirs as $dir ) {
		// Check the parent folders of the folders all exist within the creation array.
		if ( untrailingslashit( $to ) == $dir ) { // Skip over the working directory, we know this exists (or will exist).
			continue;
		}
		if ( strpos( $dir, $to ) === false ) { // If the directory is not within the working directory, skip it.
			continue;
		}

		$parent_folder = dirname( $dir );
		while ( ! empty( $parent_folder ) && untrailingslashit( $to ) != $parent_folder && ! in_array( $parent_folder, $needed_dirs, true ) ) {
			$needed_dirs[] = $parent_folder;
			$parent_folder = dirname( $parent_folder );
		}
	}
	asort( $needed_dirs );

	// Create those directories if need be:
	foreach ( $needed_dirs as $_dir ) {
		// Only check to see if the dir exists upon creation failure. Less I/O this way.
		if ( ! $wp_filesystem->mkdir( $_dir, FS_CHMOD_DIR ) && ! $wp_filesystem->is_dir( $_dir ) ) {
			return new WP_Error( 'mkdir_failed_pclzip', __( 'Could not create directory.' ), substr( $_dir, strlen( $to ) ) );
		}
	}
	unset( $needed_dirs );

	// Extract the files from the zip.
	foreach ( $archive_files as $file ) {
		if ( $file['folder'] ) {
			continue;
		}

		if ( '__MACOSX/' === substr( $file['filename'], 0, 9 ) ) { // Don't extract the OS X-created __MACOSX directory files.
			continue;
		}

		// Don't extract invalid files:
		if ( 0 !== validate_file( $file['filename'] ) ) {
			continue;
		}

		if ( ! $wp_filesystem->put_contents( $to . $file['filename'], $file['content'], FS_CHMOD_FILE ) ) {
			return new WP_Error( 'copy_failed_pclzip', __( 'Could not copy file.' ), $file['filename'] );
		}
	}
	return true;
}