dir+openbsd.myr

use sys

use "alloc"
use "die"
use "memops"
use "option"
use "result"
use "slcp"
use "sldup"
use "types"

pkg std =
	type dir = struct
		fd	: sys.fd
		buf	: byte[16384]
		len	: int64
		off	: int64
	;;

	const diropen	: (p : byte[:] -> std.result(dir#, byte[:]))
	const dirread	: (d : dir# -> std.option(byte[:]))
	const dirclose	: (d : dir# -> void)
;;

const diropen = {p
	var fd
	var dir

	fd = sys.open(p, sys.Ordonly | sys.Odir)
	if fd < 0
		-> `Err "couldn't open directory"
	;;
	dir = zalloc()
	dir.fd = fd
	-> `Ok dir
}

const dirread = {d
	var len
	var dent
	var namelen

	if d.off >= d.len
		len = sys.getdents(d.fd, d.buf[:])
		if len <= 0
			-> `None
		;;
		d.len = len
		d.off = 0
	;;

	dent = (&d.buf[d.off] : sys.dirent#)
	namelen = 0
	d.off += (dent.reclen : int64)
	while dent.name[namelen] != 0
		namelen++
	;;
	-> `Some sldup(dent.name[:namelen])
}

const dirclose = {d
	sys.close(d.fd)
	free(d)
}