os/os2: wasi target support

core/os/os2/dir_wasi.odin

@@ -0,0 +1,110 @@
+#+private
+package os2
+
+import "base:intrinsics"
+import "core:sys/wasm/wasi"
+
+Read_Directory_Iterator_Impl :: struct {
+	fullpath: [dynamic]byte,
+	buf:      []byte,
+	off:      int,
+	idx:      int,
+}
+
+@(require_results)
+_read_directory_iterator :: proc(it: ^Read_Directory_Iterator) -> (fi: File_Info, index: int, ok: bool) {
+	fimpl := (^File_Impl)(it.f.impl)
+
+	buf := it.impl.buf[it.impl.off:]
+
+	index = it.impl.idx
+	it.impl.idx += 1
+
+	for {
+		if len(buf) < size_of(wasi.dirent_t) {
+			return
+		}
+
+		entry := intrinsics.unaligned_load((^wasi.dirent_t)(raw_data(buf)))
+		buf    = buf[size_of(wasi.dirent_t):]
+
+		if len(buf) < int(entry.d_namlen) {
+			// shouldn't be possible.
+			return
+		}
+
+		name := string(buf[:entry.d_namlen])
+		buf = buf[entry.d_namlen:]
+		it.impl.off += size_of(wasi.dirent_t) + int(entry.d_namlen)
+
+		if name == "." || name == ".." {
+			continue
+		}
+
+		n := len(fimpl.name)+1
+		if alloc_err := non_zero_resize(&it.impl.fullpath, n+len(name)); alloc_err != nil {
+			// Can't really tell caller we had an error, sad.
+			return
+		}
+		copy(it.impl.fullpath[n:], name)
+
+		stat, err := wasi.path_filestat_get(__fd(it.f), {}, name)
+		if err != nil {
+			// Can't stat, fill what we have from dirent.
+			stat = {
+				ino      = entry.d_ino,
+				filetype = entry.d_type,
+			}
+		}
+
+		fi = internal_stat(stat, string(it.impl.fullpath[:]))
+		ok = true
+		return
+	}
+}
+
+@(require_results)
+_read_directory_iterator_create :: proc(f: ^File) -> (iter: Read_Directory_Iterator, err: Error) {
+	if f == nil || f.impl == nil {
+		err = .Invalid_File
+		return
+	}
+
+	impl := (^File_Impl)(f.impl)
+	iter.f = f
+
+	buf: [dynamic]byte
+	buf.allocator = file_allocator()
+	defer if err != nil { delete(buf) }
+
+	// NOTE: this is very grug.
+	for {
+		non_zero_resize(&buf, 512 if len(buf) == 0 else len(buf)*2) or_return
+
+		n, _err := wasi.fd_readdir(__fd(f), buf[:], 0)
+		if _err != nil {
+			err = _get_platform_error(_err)
+			return
+		}
+
+		if n < len(buf) {
+			non_zero_resize(&buf, n)
+			break
+		}
+
+		assert(n == len(buf))
+	}
+	iter.impl.buf = buf[:]
+
+	iter.impl.fullpath = make([dynamic]byte, 0, len(impl.name)+128, file_allocator()) or_return
+	append(&iter.impl.fullpath, impl.name)
+	append(&iter.impl.fullpath, "/")
+
+	return
+}
+
+_read_directory_iterator_destroy :: proc(it: ^Read_Directory_Iterator) {
+	delete(it.impl.buf, file_allocator())
+	delete(it.impl.fullpath)
+	it^ = {}
+}