show RemoteVolumes/EcVolumes only if it is not empty

weed/util/reflect.go

@@ -0,0 +1,40 @@
+package util
+
+import "reflect"
+
+// IsNotEmpty returns true if the given value is not zero or empty.
+func IsNotEmpty(given interface{}) bool {
+	return !IsEmpty(given)
+}
+
+// IsEmpty returns true if the given value has the zero value for its type.
+func IsEmpty(given interface{}) bool {
+	g := reflect.ValueOf(given)
+	if !g.IsValid() {
+		return true
+	}
+
+	if g.Kind() == reflect.Ptr {
+		g = g.Elem()
+	}
+
+	// Basically adapted from text/template.isTrue
+	switch g.Kind() {
+	case reflect.Array, reflect.Slice, reflect.Map, reflect.String:
+		return g.Len() == 0
+	case reflect.Bool:
+		return !g.Bool()
+	case reflect.Complex64, reflect.Complex128:
+		return g.Complex() == 0
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return g.Int() == 0
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		return g.Uint() == 0
+	case reflect.Float32, reflect.Float64:
+		return g.Float() == 0
+	case reflect.Struct:
+		return g.IsZero()
+	default:
+		return g.IsNil()
+	}
+}