Add local file system option to disable UNC on Windows.

This will add an option to disable UNC conversion on Windows to deal with buggy file system implementations like EncFS.

Fixes #261

local/local.go

@@ -22,10 +22,20 @@ import (
 
 // Register with Fs
 func init() {
-	fs.Register(&fs.Info{
+	fsi := &fs.Info{
 		Name:  "local",
 		NewFs: NewFs,
-	})
+		Options: []fs.Option{fs.Option{
+			Name:     "nounc",
+			Help:     "Disable UNC (long path names) conversion on Windows",
+			Optional: true,
+			Examples: []fs.OptionExample{{
+				Value: "true",
+				Help:  "Disables long file names",
+			}},
+		}},
+	}
+	fs.Register(fsi)
 }
 
 // Fs represents a local filesystem rooted at root
@@ -35,6 +45,7 @@ type Fs struct {
 	precisionOk sync.Once           // Whether we need to read the precision
 	precision   time.Duration       // precision of local filesystem
 	warned      map[string]struct{} // whether we have warned about this string
+	nounc       bool                // Skip UNC conversion on Windows
 }
 
 // Object represents a local filesystem object
@@ -52,11 +63,13 @@ type Object struct {
 func NewFs(name, root string) (fs.Fs, error) {
 	var err error
 
+	nounc, _ := fs.ConfigFile.GetValue(name, "nounc")
 	f := &Fs{
 		name:   name,
 		warned: make(map[string]struct{}),
+		nounc:  nounc == "true",
 	}
-	f.root = filterPath(f.cleanUtf8(root))
+	f.root = f.filterPath(f.cleanUtf8(root))
 
 	// Check to see if this points to a file
 	fi, err := os.Lstat(f.root)
@@ -89,7 +102,7 @@ func (f *Fs) String() string {
 // newFsObject makes a half completed Object
 func (f *Fs) newFsObject(remote string) *Object {
 	remote = filepath.ToSlash(remote)
-	dstPath := filterPath(filepath.Join(f.root, f.cleanUtf8(remote)))
+	dstPath := f.filterPath(filepath.Join(f.root, f.cleanUtf8(remote)))
 	return &Object{
 		fs:     f,
 		remote: remote,
@@ -195,7 +208,7 @@ func (f *Fs) ListDir() fs.DirChan {
 						Count: 0,
 					}
 					// Go down the tree to count the files and directories
-					dirpath := filterPath(filepath.Join(f.root, item.Name()))
+					dirpath := f.filterPath(filepath.Join(f.root, item.Name()))
 					err := filepath.Walk(dirpath, func(path string, fi os.FileInfo, err error) error {
 						if err != nil {
 							fs.Stats.Error()
@@ -594,7 +607,7 @@ func getDirFile(s string) (string, string) {
 	return s[:i], s[i+1:]
 }
 
-func filterPath(s string) string {
+func (f *Fs) filterPath(s string) string {
 	s = filepath.Clean(s)
 	if runtime.GOOS == "windows" {
 		s = strings.Replace(s, `/`, `\`, -1)
@@ -606,6 +619,9 @@ func filterPath(s string) string {
 			}
 		}
 
+		if f.nounc {
+			return s
+		}
 		// Convert to UNC
 		return uncPath(s)
 	}