add breadcrumb to filer UI

weed/server/filer_ui/breadcrumb.go

@@ -0,0 +1,24 @@
+package master_ui
+
+import (
+	"strings"
+	"path/filepath"
+)
+
+type Breadcrumb struct {
+	Name string
+	Link string
+}
+
+func ToBreadcrumb(fullpath string) (crumbs []Breadcrumb) {
+	parts := strings.Split(fullpath, "/")
+
+	for i := 0; i < len(parts); i++ {
+		crumbs = append(crumbs, Breadcrumb{
+			Name: parts[i] + "/",
+			Link: "/" + filepath.Join(parts[0:i+1]...),
+		})
+	}
+
+	return
+}