Added billy.Stat function that returns os.FileInfo

fs.go

@@ -200,3 +200,12 @@ func CapabilityCheck(fs Basic, capabilities Capability) bool {
 	fsCaps := Capabilities(fs)
 	return fsCaps&capabilities == capabilities
 }
+
+// Stat returns the os.FileInfo structure describing file.
+func Stat(f File) (os.FileInfo, error) {
+	fi, ok := f.(interface{ Stat() (os.FileInfo, error) })
+	if !ok {
+		return nil, ErrNotSupported
+	}
+	return fi.Stat()
+}

helper/chroot/chroot.go

@@ -222,6 +222,15 @@ func (fs *ChrootHelper) Capabilities() billy.Capability {
 	return billy.Capabilities(fs.underlying)
 }
 
+type fileInfo struct {
+	os.FileInfo
+	name string
+}
+
+func (fi *fileInfo) Name() string {
+	return fi.name
+}
+
 type file struct {
 	billy.File
 	name string
@@ -240,3 +249,12 @@ func newFile(fs billy.Filesystem, f billy.File, filename string) billy.File {
 func (f *file) Name() string {
 	return f.name
 }
+
+func (f *file) Stat() (os.FileInfo, error) {
+	fi, err := billy.Stat(f.File)
+	if err != nil {
+		return fi, err
+	}
+	name := f.Name()
+	return &fileInfo{fi, name}, nil
+}