style: Drop the manually implementation of ToCSS for BasicShape::Polygon.

The implementation of ToCSS for Polygon has some rule, and we could use skip_if
to handle and serialization of fill-rule. However, we should derive ToCSS for
the pair of LengthOrPercentages, so define a new type for it.

Differential Revision: https://phabricator.services.mozilla.com/D4153

1 files changed, 16 insertions, 29 deletions

diff --git a/components/style/values/generics/basic_shape.rs b/components/style/values/generics/basic_shape.rs
index 3bad738c1e6..274673b9c61 100644
--- a/components/style/values/generics/basic_shape.rs
+++ b/components/style/values/generics/basic_shape.rs
@@ -113,16 +113,23 @@ pub enum ShapeRadius<LengthOrPercentage> {
 /// A generic type for representing the `polygon()` function
 ///
 /// <https://drafts.csswg.org/css-shapes/#funcdef-polygon>
-#[css(function)]
+#[css(comma, function)]
 #[derive(Clone, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo,
-         ToComputedValue)]
+         ToComputedValue, ToCss)]
 pub struct Polygon<LengthOrPercentage> {
     /// The filling rule for a polygon.
+    #[css(skip_if = "fill_is_default")]
     pub fill: FillRule,
     /// A collection of (x, y) coordinates to draw the polygon.
-    pub coordinates: Vec<(LengthOrPercentage, LengthOrPercentage)>,
+    #[css(iterable)]
+    pub coordinates: Vec<PolygonCoord<LengthOrPercentage>>,
 }
 
+/// Coordinates for Polygon.
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo,
+         ToComputedValue, ToCss)]
+pub struct PolygonCoord<LengthOrPercentage>(pub LengthOrPercentage, pub LengthOrPercentage);
+
 // https://drafts.csswg.org/css-shapes/#typedef-fill-rule
 // NOTE: Basic shapes spec says that these are the only two values, however
 // https://www.w3.org/TR/SVG/painting.html#FillRuleProperty
@@ -203,7 +210,7 @@ where
             .iter()
             .zip(other.coordinates.iter())
             .map(|(this, other)| {
-                Ok((
+                Ok(PolygonCoord(
                     this.0.animate(&other.0, procedure)?,
                     this.1.animate(&other.1, procedure)?,
                 ))
@@ -239,34 +246,14 @@ where
     }
 }
 
-impl<L: ToCss> ToCss for Polygon<L> {
-    fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result
-    where
-        W: Write,
-    {
-        dest.write_str("polygon(")?;
-        if self.fill != FillRule::default() {
-            self.fill.to_css(dest)?;
-            dest.write_str(", ")?;
-        }
-
-        for (i, coord) in self.coordinates.iter().enumerate() {
-            if i > 0 {
-                dest.write_str(", ")?;
-            }
-
-            coord.0.to_css(dest)?;
-            dest.write_str(" ")?;
-            coord.1.to_css(dest)?;
-        }
-
-        dest.write_str(")")
-    }
-}
-
 impl Default for FillRule {
     #[inline]
     fn default() -> Self {
         FillRule::Nonzero
     }
 }
+
+#[inline]
+fn fill_is_default(fill: &FillRule) -> bool {
+    *fill == FillRule::default()
+}