rewrite in go

vendor/github.com/spf13/afero/readonlyfs.go

@@ -0,0 +1,96 @@
+package afero
+
+import (
+	"os"
+	"syscall"
+	"time"
+)
+
+var _ Lstater = (*ReadOnlyFs)(nil)
+
+type ReadOnlyFs struct {
+	source Fs
+}
+
+func NewReadOnlyFs(source Fs) Fs {
+	return &ReadOnlyFs{source: source}
+}
+
+func (r *ReadOnlyFs) ReadDir(name string) ([]os.FileInfo, error) {
+	return ReadDir(r.source, name)
+}
+
+func (r *ReadOnlyFs) Chtimes(n string, a, m time.Time) error {
+	return syscall.EPERM
+}
+
+func (r *ReadOnlyFs) Chmod(n string, m os.FileMode) error {
+	return syscall.EPERM
+}
+
+func (r *ReadOnlyFs) Chown(n string, uid, gid int) error {
+	return syscall.EPERM
+}
+
+func (r *ReadOnlyFs) Name() string {
+	return "ReadOnlyFilter"
+}
+
+func (r *ReadOnlyFs) Stat(name string) (os.FileInfo, error) {
+	return r.source.Stat(name)
+}
+
+func (r *ReadOnlyFs) LstatIfPossible(name string) (os.FileInfo, bool, error) {
+	if lsf, ok := r.source.(Lstater); ok {
+		return lsf.LstatIfPossible(name)
+	}
+	fi, err := r.Stat(name)
+	return fi, false, err
+}
+
+func (r *ReadOnlyFs) SymlinkIfPossible(oldname, newname string) error {
+	return &os.LinkError{Op: "symlink", Old: oldname, New: newname, Err: ErrNoSymlink}
+}
+
+func (r *ReadOnlyFs) ReadlinkIfPossible(name string) (string, error) {
+	if srdr, ok := r.source.(LinkReader); ok {
+		return srdr.ReadlinkIfPossible(name)
+	}
+
+	return "", &os.PathError{Op: "readlink", Path: name, Err: ErrNoReadlink}
+}
+
+func (r *ReadOnlyFs) Rename(o, n string) error {
+	return syscall.EPERM
+}
+
+func (r *ReadOnlyFs) RemoveAll(p string) error {
+	return syscall.EPERM
+}
+
+func (r *ReadOnlyFs) Remove(n string) error {
+	return syscall.EPERM
+}
+
+func (r *ReadOnlyFs) OpenFile(name string, flag int, perm os.FileMode) (File, error) {
+	if flag&(os.O_WRONLY|syscall.O_RDWR|os.O_APPEND|os.O_CREATE|os.O_TRUNC) != 0 {
+		return nil, syscall.EPERM
+	}
+	return r.source.OpenFile(name, flag, perm)
+}
+
+func (r *ReadOnlyFs) Open(n string) (File, error) {
+	return r.source.Open(n)
+}
+
+func (r *ReadOnlyFs) Mkdir(n string, p os.FileMode) error {
+	return syscall.EPERM
+}
+
+func (r *ReadOnlyFs) MkdirAll(n string, p os.FileMode) error {
+	return syscall.EPERM
+}
+
+func (r *ReadOnlyFs) Create(n string) (File, error) {
+	return nil, syscall.EPERM
+}