Source

File: wp-includes/pomo/po.php

function import_from_file( $filename ) {
			$f = fopen( $filename, 'r' );
			if ( ! $f ) {
				return false;
			}
			$lineno = 0;
			while ( true ) {
				$res = $this->read_entry( $f, $lineno );
				if ( ! $res ) {
					break;
				}
				if ( '' === $res['entry']->singular ) {
					$this->set_headers( $this->make_headers( $res['entry']->translations[0] ) );
				} else {
					$this->add_entry( $res['entry'] );
				}
			}
			PO::read_line( $f, 'clear' );
			if ( false === $res ) {
				return false;
			}
			if ( ! $this->headers && ! $this->entries ) {
				return false;
			}
			return true;
		}