Source

File: wp-admin/includes/class-wp-filesystem-direct.php

public function dirlist( $path, $include_hidden = true, $recursive = false ) {
		if ( $this->is_file( $path ) ) {
			$limit_file = basename( $path );
			$path       = dirname( $path );
		} else {
			$limit_file = false;
		}

		if ( ! $this->is_dir( $path ) || ! $this->is_readable( $path ) ) {
			return false;
		}

		$dir = dir( $path );

		if ( ! $dir ) {
			return false;
		}

		$ret = array();

		while ( false !== ( $entry = $dir->read() ) ) {
			$struc         = array();
			$struc['name'] = $entry;

			if ( '.' === $struc['name'] || '..' === $struc['name'] ) {
				continue;
			}

			if ( ! $include_hidden && '.' === $struc['name'][0] ) {
				continue;
			}

			if ( $limit_file && $struc['name'] != $limit_file ) {
				continue;
			}

			$struc['perms']       = $this->gethchmod( $path . '/' . $entry );
			$struc['permsn']      = $this->getnumchmodfromh( $struc['perms'] );
			$struc['number']      = false;
			$struc['owner']       = $this->owner( $path . '/' . $entry );
			$struc['group']       = $this->group( $path . '/' . $entry );
			$struc['size']        = $this->size( $path . '/' . $entry );
			$struc['lastmodunix'] = $this->mtime( $path . '/' . $entry );
			$struc['lastmod']     = gmdate( 'M j', $struc['lastmodunix'] );
			$struc['time']        = gmdate( 'h:i:s', $struc['lastmodunix'] );
			$struc['type']        = $this->is_dir( $path . '/' . $entry ) ? 'd' : 'f';

			if ( 'd' === $struc['type'] ) {
				if ( $recursive ) {
					$struc['files'] = $this->dirlist( $path . '/' . $struc['name'], $include_hidden, $recursive );
				} else {
					$struc['files'] = array();
				}
			}

			$ret[ $struc['name'] ] = $struc;
		}

		$dir->close();
		unset( $dir );

		return $ret;
	}