Add impl GeckoStyleCoordConvertible for Either<A, B>

components/style/gecko/values.rs

@@ -10,6 +10,7 @@ use gecko_bindings::structs::{NS_RADIUS_CLOSEST_SIDE, NS_RADIUS_FARTHEST_SIDE};
 use gecko_bindings::structs::nsStyleCoord;
 use gecko_bindings::sugar::ns_style_coord::{CoordData, CoordDataMut, CoordDataValue};
 use std::cmp::max;
+use values::Either;
 use values::computed::{LengthOrNumber, LengthOrPercentage, LengthOrPercentageOrAuto};
 use values::computed::{LengthOrPercentageOrNone, Angle};
 use values::computed::basic_shape::ShapeRadius;
@@ -31,6 +32,21 @@ pub trait GeckoStyleCoordConvertible : Sized {
     fn from_gecko_style_coord<T: CoordData>(coord: &T) -> Option<Self>;
 }
 
+impl<A: GeckoStyleCoordConvertible, B: GeckoStyleCoordConvertible> GeckoStyleCoordConvertible for Either<A, B> {
+    fn to_gecko_style_coord<T: CoordDataMut>(&self, coord: &mut T) {
+        match *self {
+            Either::First(ref v) => v.to_gecko_style_coord(coord),
+            Either::Second(ref v) => v.to_gecko_style_coord(coord),
+        }
+    }
+
+    fn from_gecko_style_coord<T: CoordData>(coord: &T) -> Option<Self> {
+        A::from_gecko_style_coord(coord)
+          .map(Either::First)
+          .or_else(|| B::from_gecko_style_coord(coord).map(Either::Second))
+    }
+}
+
 impl GeckoStyleCoordConvertible for LengthOrPercentage {
     fn to_gecko_style_coord<T: CoordDataMut>(&self, coord: &mut T) {
         let value = match *self {