--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/vendor/github.com/spf13/afero/basepath.go	Sat Sep 29 18:09:54 2018 +0200
@@ -0,0 +1,180 @@
+package afero
+
+import (
+	"os"
+	"path/filepath"
+	"runtime"
+	"strings"
+	"time"
+)
+
+var _ Lstater = (*BasePathFs)(nil)
+
+// The BasePathFs restricts all operations to a given path within an Fs.
+// The given file name to the operations on this Fs will be prepended with
+// the base path before calling the base Fs.
+// Any file name (after filepath.Clean()) outside this base path will be
+// treated as non existing file.
+//
+// Note that it does not clean the error messages on return, so you may
+// reveal the real path on errors.
+type BasePathFs struct {
+	source Fs
+	path   string
+}
+
+type BasePathFile struct {
+	File
+	path string
+}
+
+func (f *BasePathFile) Name() string {
+	sourcename := f.File.Name()
+	return strings.TrimPrefix(sourcename, filepath.Clean(f.path))
+}
+
+func NewBasePathFs(source Fs, path string) Fs {
+	return &BasePathFs{source: source, path: path}
+}
+
+// on a file outside the base path it returns the given file name and an error,
+// else the given file with the base path prepended
+func (b *BasePathFs) RealPath(name string) (path string, err error) {
+	if err := validateBasePathName(name); err != nil {
+		return name, err
+	}
+
+	bpath := filepath.Clean(b.path)
+	path = filepath.Clean(filepath.Join(bpath, name))
+	if !strings.HasPrefix(path, bpath) {
+		return name, os.ErrNotExist
+	}
+
+	return path, nil
+}
+
+func validateBasePathName(name string) error {
+	if runtime.GOOS != "windows" {
+		// Not much to do here;
+		// the virtual file paths all look absolute on *nix.
+		return nil
+	}
+
+	// On Windows a common mistake would be to provide an absolute OS path
+	// We could strip out the base part, but that would not be very portable.
+	if filepath.IsAbs(name) {
+		return os.ErrNotExist
+	}
+
+	return nil
+}
+
+func (b *BasePathFs) Chtimes(name string, atime, mtime time.Time) (err error) {
+	if name, err = b.RealPath(name); err != nil {
+		return &os.PathError{Op: "chtimes", Path: name, Err: err}
+	}
+	return b.source.Chtimes(name, atime, mtime)
+}
+
+func (b *BasePathFs) Chmod(name string, mode os.FileMode) (err error) {
+	if name, err = b.RealPath(name); err != nil {
+		return &os.PathError{Op: "chmod", Path: name, Err: err}
+	}
+	return b.source.Chmod(name, mode)
+}
+
+func (b *BasePathFs) Name() string {
+	return "BasePathFs"
+}
+
+func (b *BasePathFs) Stat(name string) (fi os.FileInfo, err error) {
+	if name, err = b.RealPath(name); err != nil {
+		return nil, &os.PathError{Op: "stat", Path: name, Err: err}
+	}
+	return b.source.Stat(name)
+}
+
+func (b *BasePathFs) Rename(oldname, newname string) (err error) {
+	if oldname, err = b.RealPath(oldname); err != nil {
+		return &os.PathError{Op: "rename", Path: oldname, Err: err}
+	}
+	if newname, err = b.RealPath(newname); err != nil {
+		return &os.PathError{Op: "rename", Path: newname, Err: err}
+	}
+	return b.source.Rename(oldname, newname)
+}
+
+func (b *BasePathFs) RemoveAll(name string) (err error) {
+	if name, err = b.RealPath(name); err != nil {
+		return &os.PathError{Op: "remove_all", Path: name, Err: err}
+	}
+	return b.source.RemoveAll(name)
+}
+
+func (b *BasePathFs) Remove(name string) (err error) {
+	if name, err = b.RealPath(name); err != nil {
+		return &os.PathError{Op: "remove", Path: name, Err: err}
+	}
+	return b.source.Remove(name)
+}
+
+func (b *BasePathFs) OpenFile(name string, flag int, mode os.FileMode) (f File, err error) {
+	if name, err = b.RealPath(name); err != nil {
+		return nil, &os.PathError{Op: "openfile", Path: name, Err: err}
+	}
+	sourcef, err := b.source.OpenFile(name, flag, mode)
+	if err != nil {
+		return nil, err
+	}
+	return &BasePathFile{sourcef, b.path}, nil
+}
+
+func (b *BasePathFs) Open(name string) (f File, err error) {
+	if name, err = b.RealPath(name); err != nil {
+		return nil, &os.PathError{Op: "open", Path: name, Err: err}
+	}
+	sourcef, err := b.source.Open(name)
+	if err != nil {
+		return nil, err
+	}
+	return &BasePathFile{File: sourcef, path: b.path}, nil
+}
+
+func (b *BasePathFs) Mkdir(name string, mode os.FileMode) (err error) {
+	if name, err = b.RealPath(name); err != nil {
+		return &os.PathError{Op: "mkdir", Path: name, Err: err}
+	}
+	return b.source.Mkdir(name, mode)
+}
+
+func (b *BasePathFs) MkdirAll(name string, mode os.FileMode) (err error) {
+	if name, err = b.RealPath(name); err != nil {
+		return &os.PathError{Op: "mkdir", Path: name, Err: err}
+	}
+	return b.source.MkdirAll(name, mode)
+}
+
+func (b *BasePathFs) Create(name string) (f File, err error) {
+	if name, err = b.RealPath(name); err != nil {
+		return nil, &os.PathError{Op: "create", Path: name, Err: err}
+	}
+	sourcef, err := b.source.Create(name)
+	if err != nil {
+		return nil, err
+	}
+	return &BasePathFile{File: sourcef, path: b.path}, nil
+}
+
+func (b *BasePathFs) LstatIfPossible(name string) (os.FileInfo, bool, error) {
+	name, err := b.RealPath(name)
+	if err != nil {
+		return nil, false, &os.PathError{Op: "lstat", Path: name, Err: err}
+	}
+	if lstater, ok := b.source.(Lstater); ok {
+		return lstater.LstatIfPossible(name)
+	}
+	fi, err := b.source.Stat(name)
+	return fi, false, err
+}
+
+// vim: ts=4 sw=4 noexpandtab nolist syn=go