From a4ede9f9a6254360d39d0f45aec133c355ac6b2a Mon Sep 17 00:00:00 2001 From: Russ Cox Date: Fri, 9 Oct 2020 11:49:59 -0400 Subject: os: add File.ReadDir method and DirEntry type ReadDir provides a portable, efficient way to read a directory and discover the type of directory entries. This enables a more efficient file system walk, yet to be added. See #41467 for the proposal review for the API. Fixes #41467. Change-Id: I461a526793ae46df48821aa448b04f1705546739 Reviewed-on: https://go-review.googlesource.com/c/go/+/261540 Trust: Russ Cox Run-TryBot: Russ Cox Reviewed-by: Rob Pike --- src/os/dirent_linux.go | 51 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 51 insertions(+) create mode 100644 src/os/dirent_linux.go (limited to 'src/os/dirent_linux.go') diff --git a/src/os/dirent_linux.go b/src/os/dirent_linux.go new file mode 100644 index 0000000000..74a3431121 --- /dev/null +++ b/src/os/dirent_linux.go @@ -0,0 +1,51 @@ +// Copyright 2020 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package os + +import ( + "syscall" + "unsafe" +) + +func direntIno(buf []byte) (uint64, bool) { + return readInt(buf, unsafe.Offsetof(syscall.Dirent{}.Ino), unsafe.Sizeof(syscall.Dirent{}.Ino)) +} + +func direntReclen(buf []byte) (uint64, bool) { + return readInt(buf, unsafe.Offsetof(syscall.Dirent{}.Reclen), unsafe.Sizeof(syscall.Dirent{}.Reclen)) +} + +func direntNamlen(buf []byte) (uint64, bool) { + reclen, ok := direntReclen(buf) + if !ok { + return 0, false + } + return reclen - uint64(unsafe.Offsetof(syscall.Dirent{}.Name)), true +} + +func direntType(buf []byte) FileMode { + off := unsafe.Offsetof(syscall.Dirent{}.Type) + if off >= uintptr(len(buf)) { + return ^FileMode(0) // unknown + } + typ := buf[off] + switch typ { + case syscall.DT_BLK: + return ModeDevice + case syscall.DT_CHR: + return ModeDevice | ModeCharDevice + case syscall.DT_DIR: + return ModeDir + case syscall.DT_FIFO: + return ModeNamedPipe + case syscall.DT_LNK: + return ModeSymlink + case syscall.DT_REG: + return 0 + case syscall.DT_SOCK: + return ModeSocket + } + return ^FileMode(0) // unknown +} -- cgit v1.2.1