style: Use rust lengths for border corners.

The test in https://github.com/web-platform-tests/wpt/pull/15423 hasn't been
synced over yet, but it passes with this patch of course.

Differential Revision: https://phabricator.services.mozilla.com/D20960

7 files changed, 51 insertions, 174 deletions

diff --git a/components/style/cbindgen.toml b/components/style/cbindgen.toml
index 0b8719c4dbf..82ed48ab290 100644
--- a/components/style/cbindgen.toml
+++ b/components/style/cbindgen.toml
@@ -13,6 +13,7 @@ autogen_warning = """/* DO NOT MODIFY THIS MANUALLY! This file was generated usi
 class nsAtom;
 namespace mozilla {
   class WritingMode;
+  enum HalfCorner : uint8_t;
   enum LogicalSide : uint8_t;
   namespace css {
     struct URLValue;
@@ -88,6 +89,8 @@ include = [
   "Position",
   "BackgroundSize",
   "BorderImageSlice",
+  "BorderSpacing",
+  "BorderRadius",
   "NonNegativeLengthOrNumberRect",
   "Perspective",
   "ZIndex",
@@ -185,3 +188,7 @@ item_types = ["enums", "structs", "typedefs"]
   inline const T& GetIEnd(mozilla::WritingMode) const;
   inline const T& GetBEnd(mozilla::WritingMode) const;
 """
+
+"GenericBorderRadius" = """
+  inline const StyleLengthPercentage& Get(mozilla::HalfCorner) const;
+"""
diff --git a/components/style/gecko/conversions.rs b/components/style/gecko/conversions.rs
index 2a2ae268395..4cbf759c2d8 100644
--- a/components/style/gecko/conversions.rs
+++ b/components/style/gecko/conversions.rs
@@ -575,17 +575,15 @@ pub mod basic_shape {
     //! Conversions from and to CSS shape representations.
 
     use crate::gecko::values::GeckoStyleCoordConvertible;
-    use crate::gecko_bindings::structs::{nsStyleCoord, nsStyleCorners};
+    use crate::gecko_bindings::structs::nsStyleCoord;
     use crate::gecko_bindings::structs::{StyleBasicShape, StyleBasicShapeType};
     use crate::gecko_bindings::structs::{
         StyleGeometryBox, StyleShapeSource, StyleShapeSourceType,
     };
-    use crate::gecko_bindings::sugar::ns_style_coord::{CoordDataMut, CoordDataValue};
     use crate::gecko_bindings::sugar::refptr::RefPtr;
     use crate::values::computed::basic_shape::{
         BasicShape, ClippingShape, FloatAreaShape, ShapeRadius,
     };
-    use crate::values::computed::border::{BorderCornerRadius, BorderRadius};
     use crate::values::computed::length::LengthPercentage;
     use crate::values::computed::motion::OffsetPath;
     use crate::values::computed::url::ComputedUrl;
@@ -594,9 +592,7 @@ pub mod basic_shape {
     };
     use crate::values::generics::basic_shape::{Circle, Ellipse, Path, PolygonCoord};
     use crate::values::generics::basic_shape::{GeometryBox, ShapeBox, ShapeSource};
-    use crate::values::generics::border::BorderRadius as GenericBorderRadius;
     use crate::values::generics::rect::Rect;
-    use crate::values::generics::NonNegative;
     use crate::values::specified::SVGPathData;
     use std::borrow::Borrow;
 
@@ -706,7 +702,7 @@ pub mod basic_shape {
                     let r = LengthPercentage::from_gecko_style_coord(&other.mCoordinates[1]);
                     let b = LengthPercentage::from_gecko_style_coord(&other.mCoordinates[2]);
                     let l = LengthPercentage::from_gecko_style_coord(&other.mCoordinates[3]);
-                    let round: BorderRadius = (&other.mRadius).into();
+                    let round = other.mRadius;
                     let round = if round.all_zero() { None } else { Some(round) };
                     let rect = Rect::new(
                         t.expect("inset() offset should be a length, percentage, or calc value"),
@@ -752,65 +748,6 @@ pub mod basic_shape {
         }
     }
 
-    impl<'a> From<&'a nsStyleCorners> for BorderRadius {
-        fn from(other: &'a nsStyleCorners) -> Self {
-            let get_corner = |index| {
-                BorderCornerRadius::new(
-                    NonNegative(
-                        LengthPercentage::from_gecko_style_coord(&other.data_at(index)).expect(
-                            "<border-radius> should be a length, percentage, or calc value",
-                        ),
-                    ),
-                    NonNegative(
-                        LengthPercentage::from_gecko_style_coord(&other.data_at(index + 1)).expect(
-                            "<border-radius> should be a length, percentage, or calc value",
-                        ),
-                    ),
-                )
-            };
-
-            GenericBorderRadius {
-                top_left: get_corner(0),
-                top_right: get_corner(2),
-                bottom_right: get_corner(4),
-                bottom_left: get_corner(6),
-            }
-        }
-    }
-
-    // Can't be a From impl since we need to set an existing
-    // nsStyleCorners, not create a new one
-    impl BorderRadius {
-        /// Set this `BorderRadius` into a given `nsStyleCoord`.
-        pub fn set_corners(&self, other: &mut nsStyleCorners) {
-            let mut set_corner = |field: &BorderCornerRadius, index| {
-                field
-                    .0
-                    .width()
-                    .to_gecko_style_coord(&mut other.data_at_mut(index));
-                field
-                    .0
-                    .height()
-                    .to_gecko_style_coord(&mut other.data_at_mut(index + 1));
-            };
-            set_corner(&self.top_left, 0);
-            set_corner(&self.top_right, 2);
-            set_corner(&self.bottom_right, 4);
-            set_corner(&self.bottom_left, 6);
-        }
-    }
-
-    /// We use None for a nonexistant radius, but Gecko uses (0 0 0 0 / 0 0 0 0)
-    pub fn set_corners_from_radius(radius: Option<BorderRadius>, other: &mut nsStyleCorners) {
-        if let Some(radius) = radius {
-            radius.set_corners(other);
-        } else {
-            for i in 0..8 {
-                other.data_at_mut(i).set_value(CoordDataValue::Coord(0));
-            }
-        }
-    }
-
     impl<'a> From<&'a nsStyleCoord> for ShapeRadius {
         fn from(other: &'a nsStyleCoord) -> Self {
             let other = other.borrow();
diff --git a/components/style/gecko_bindings/sugar/ns_style_coord.rs b/components/style/gecko_bindings/sugar/ns_style_coord.rs
index 4f188297d5e..133ce4d9b7b 100644
--- a/components/style/gecko_bindings/sugar/ns_style_coord.rs
+++ b/components/style/gecko_bindings/sugar/ns_style_coord.rs
@@ -6,7 +6,7 @@
 
 use crate::gecko_bindings::bindings;
 use crate::gecko_bindings::structs::{nsStyleCoord, nsStyleCoord_Calc, nsStyleCoord_CalcValue};
-use crate::gecko_bindings::structs::{nsStyleCorners, nsStyleSides};
+use crate::gecko_bindings::structs::nsStyleSides;
 use crate::gecko_bindings::structs::{nsStyleUnion, nsStyleUnit, nscoord};
 use std::mem;
 
@@ -123,64 +123,6 @@ unsafe impl<'a> CoordDataMut for SidesDataMut<'a> {
     }
 }
 
-impl nsStyleCorners {
-    /// Get a `nsStyleCoord` like object representing the given index's value
-    /// and unit.
-    #[inline]
-    pub fn data_at(&self, index: usize) -> CornersData {
-        CornersData {
-            corners: self,
-            index: index,
-        }
-    }
-
-    /// Get a `nsStyleCoord` like object representing the mutable given index's
-    /// value and unit.
-    #[inline]
-    pub fn data_at_mut(&mut self, index: usize) -> CornersDataMut {
-        CornersDataMut {
-            corners: self,
-            index: index,
-        }
-    }
-}
-
-/// A `nsStyleCoord`-like struct on top of `nsStyleCorners`.
-pub struct CornersData<'a> {
-    corners: &'a nsStyleCorners,
-    index: usize,
-}
-
-/// A `nsStyleCoord`-like struct on top of a mutable `nsStyleCorners` reference.
-pub struct CornersDataMut<'a> {
-    corners: &'a mut nsStyleCorners,
-    index: usize,
-}
-
-unsafe impl<'a> CoordData for CornersData<'a> {
-    fn unit(&self) -> nsStyleUnit {
-        unsafe { self.corners.get_mUnits()[self.index] }
-    }
-    fn union(&self) -> nsStyleUnion {
-        unsafe { self.corners.get_mValues()[self.index] }
-    }
-}
-unsafe impl<'a> CoordData for CornersDataMut<'a> {
-    fn unit(&self) -> nsStyleUnit {
-        unsafe { self.corners.get_mUnits()[self.index] }
-    }
-    fn union(&self) -> nsStyleUnion {
-        unsafe { self.corners.get_mValues()[self.index] }
-    }
-}
-unsafe impl<'a> CoordDataMut for CornersDataMut<'a> {
-    unsafe fn values_mut(&mut self) -> (&mut nsStyleUnit, &mut nsStyleUnion) {
-        let unit = &mut self.corners.get_mUnits_mut()[self.index] as *mut _;
-        let value = &mut self.corners.get_mValues_mut()[self.index] as *mut _;
-        (&mut *unit, &mut *value)
-    }
-}
-
 /// Enum representing the tagged union that is CoordData.
 ///
 /// In release mode this should never actually exist in the code, and will be
diff --git a/components/style/properties/gecko.mako.rs b/components/style/properties/gecko.mako.rs
index b1be315e7a0..65ee8bc1053 100644
--- a/components/style/properties/gecko.mako.rs
+++ b/components/style/properties/gecko.mako.rs
@@ -52,7 +52,7 @@ use crate::rule_tree::StrongRuleNode;
 use crate::selector_parser::PseudoElement;
 use servo_arc::{Arc, RawOffsetArc};
 use std::marker::PhantomData;
-use std::mem::{forget, uninitialized, transmute, zeroed};
+use std::mem::{forget, uninitialized, zeroed};
 use std::{cmp, ops, ptr};
 use crate::values::{self, CustomIdent, Either, KeyframesName, None_};
 use crate::values::computed::{NonNegativeLength, Percentage, TransitionProperty};
@@ -817,34 +817,23 @@ def set_gecko_property(ffi_name, expr):
     }
 </%def>
 
-<%def name="impl_corner_style_coord(ident, gecko_ffi_name, x_index, y_index)">
+<%def name="impl_corner_style_coord(ident, gecko_ffi_name, corner)">
     #[allow(non_snake_case)]
     pub fn set_${ident}(&mut self, v: longhands::${ident}::computed_value::T) {
-        v.0.width().to_gecko_style_coord(&mut self.gecko.${gecko_ffi_name}.data_at_mut(${x_index}));
-        v.0.height().to_gecko_style_coord(&mut self.gecko.${gecko_ffi_name}.data_at_mut(${y_index}));
+        self.gecko.${gecko_ffi_name}.${corner} = v;
     }
     #[allow(non_snake_case)]
     pub fn copy_${ident}_from(&mut self, other: &Self) {
-        self.gecko.${gecko_ffi_name}.data_at_mut(${x_index})
-                  .copy_from(&other.gecko.${gecko_ffi_name}.data_at(${x_index}));
-        self.gecko.${gecko_ffi_name}.data_at_mut(${y_index})
-                  .copy_from(&other.gecko.${gecko_ffi_name}.data_at(${y_index}));
+        self.gecko.${gecko_ffi_name}.${corner} =
+            other.gecko.${gecko_ffi_name}.${corner};
     }
     #[allow(non_snake_case)]
     pub fn reset_${ident}(&mut self, other: &Self) {
         self.copy_${ident}_from(other)
     }
-
     #[allow(non_snake_case)]
     pub fn clone_${ident}(&self) -> longhands::${ident}::computed_value::T {
-        use crate::values::computed::border::BorderCornerRadius;
-        let width = GeckoStyleCoordConvertible::from_gecko_style_coord(
-                        &self.gecko.${gecko_ffi_name}.data_at(${x_index}))
-                        .expect("Failed to clone ${ident}");
-        let height = GeckoStyleCoordConvertible::from_gecko_style_coord(
-                        &self.gecko.${gecko_ffi_name}.data_at(${y_index}))
-                        .expect("Failed to clone ${ident}");
-        BorderCornerRadius::new(width, height)
+        self.gecko.${gecko_ffi_name}.${corner}
     }
 </%def>
 
@@ -1387,14 +1376,6 @@ class Side(object):
         self.ident = name.lower()
         self.index = index
 
-class Corner(object):
-    def __init__(self, vert, horiz, index):
-        self.x_name = "HalfCorner::eCorner" + vert + horiz + "X"
-        self.y_name = "HalfCorner::eCorner" + vert + horiz + "Y"
-        self.ident = (vert + "_" + horiz).lower()
-        self.x_index = 2 * index
-        self.y_index = 2 * index + 1
-
 class GridLine(object):
     def __init__(self, name):
         self.ident = "grid-" + name.lower()
@@ -1402,19 +1383,12 @@ class GridLine(object):
         self.gecko = "m" + to_camel_case(self.ident)
 
 SIDES = [Side("Top", 0), Side("Right", 1), Side("Bottom", 2), Side("Left", 3)]
-CORNERS = [Corner("Top", "Left", 0), Corner("Top", "Right", 1),
-           Corner("Bottom", "Right", 2), Corner("Bottom", "Left", 3)]
+CORNERS = ["top_left", "top_right", "bottom_right", "bottom_left"]
 GRID_LINES = map(GridLine, ["row-start", "row-end", "column-start", "column-end"])
 %>
 
 #[allow(dead_code)]
 fn static_assert() {
-    unsafe {
-        % for corner in CORNERS:
-        transmute::<_, [u32; ${corner.x_index}]>([1; structs::${corner.x_name} as usize]);
-        transmute::<_, [u32; ${corner.y_index}]>([1; structs::${corner.y_name} as usize]);
-        % endfor
-    }
     // Note: using the above technique with an enum hits a rust bug when |structs| is in a different crate.
     % for side in SIDES:
     { const DETAIL: u32 = [0][(structs::Side::eSide${side.name} as usize != ${side.index}) as usize]; let _ = DETAIL; }
@@ -1425,7 +1399,7 @@ fn static_assert() {
 <% skip_border_longhands = " ".join(["border-{0}-{1}".format(x.ident, y)
                                      for x in SIDES
                                      for y in ["color", "style", "width"]] +
-                                    ["border-{0}-radius".format(x.ident.replace("_", "-"))
+                                    ["border-{0}-radius".format(x.replace("_", "-"))
                                      for x in CORNERS]) %>
 
 <%self:impl_trait style_struct_name="Border"
@@ -1494,10 +1468,9 @@ fn static_assert() {
     % endfor
 
     % for corner in CORNERS:
-    <% impl_corner_style_coord("border_%s_radius" % corner.ident,
+    <% impl_corner_style_coord("border_%s_radius" % corner,
                                "mBorderRadius",
-                               corner.x_index,
-                               corner.y_index) %>
+                               corner) %>
     % endfor
 
     pub fn set_border_image_source(&mut self, image: longhands::border_image_source::computed_value::T) {
@@ -2027,7 +2000,7 @@ fn static_assert() {
 </%self:impl_trait>
 
 <% skip_outline_longhands = " ".join("outline-style outline-width".split() +
-                                     ["-moz-outline-radius-{0}".format(x.ident.replace("_", ""))
+                                     ["-moz-outline-radius-{0}".format(x.replace("_", ""))
                                       for x in CORNERS]) %>
 <%self:impl_trait style_struct_name="Outline"
                   skip_longhands="${skip_outline_longhands}">
@@ -2059,10 +2032,9 @@ fn static_assert() {
                                 round_to_pixels=True) %>
 
     % for corner in CORNERS:
-    <% impl_corner_style_coord("_moz_outline_radius_%s" % corner.ident.replace("_", ""),
+    <% impl_corner_style_coord("_moz_outline_radius_%s" % corner.replace("_", ""),
                                "mOutlineRadius",
-                               corner.x_index,
-                               corner.y_index) %>
+                               corner) %>
     % endfor
 
     pub fn outline_has_nonzero_width(&self) -> bool {
@@ -4593,7 +4565,6 @@ fn set_style_svg_path(
         use crate::gecko_bindings::bindings::{Gecko_NewBasicShape, Gecko_DestroyShapeSource};
         use crate::gecko_bindings::structs::{StyleBasicShape, StyleBasicShapeType, StyleShapeSourceType};
         use crate::gecko_bindings::structs::{StyleGeometryBox, StyleShapeSource};
-        use crate::gecko::conversions::basic_shape::set_corners_from_radius;
         use crate::gecko::values::GeckoStyleCoordConvertible;
         use crate::values::generics::basic_shape::{BasicShape, ShapeSource};
 
@@ -4658,8 +4629,10 @@ fn set_style_svg_path(
                         inset.rect.2.to_gecko_style_coord(&mut shape.mCoordinates[2]);
                         shape.mCoordinates[3].leaky_set_null();
                         inset.rect.3.to_gecko_style_coord(&mut shape.mCoordinates[3]);
-
-                        set_corners_from_radius(inset.round, &mut shape.mRadius);
+                        shape.mRadius = match inset.round {
+                            Some(radius) => radius,
+                            None => crate::values::computed::BorderRadius::zero(),
+                        };
                     }
                     BasicShape::Circle(circ) => {
                         let shape = init_shape(${ident}, StyleBasicShapeType::Circle);
diff --git a/components/style/values/computed/border.rs b/components/style/values/computed/border.rs
index 7b42dd0e879..0d4862ee469 100644
--- a/components/style/values/computed/border.rs
+++ b/components/style/values/computed/border.rs
@@ -87,6 +87,16 @@ impl BorderCornerRadius {
 }
 
 impl BorderRadius {
+    /// Returns a `0` border radius.
+    pub fn zero() -> Self {
+        Self {
+            top_left: BorderCornerRadius::zero(),
+            top_right: BorderCornerRadius::zero(),
+            bottom_right: BorderCornerRadius::zero(),
+            bottom_left: BorderCornerRadius::zero(),
+        }
+    }
+
     /// Returns whether all the values are `0px`.
     pub fn all_zero(&self) -> bool {
         fn all(corner: &BorderCornerRadius) -> bool {
diff --git a/components/style/values/generics/border.rs b/components/style/values/generics/border.rs
index 148f74e3834..bfc7ac5814a 100644
--- a/components/style/values/generics/border.rs
+++ b/components/style/values/generics/border.rs
@@ -53,7 +53,10 @@ pub use self::GenericBorderImageSlice as BorderImageSlice;
     ToComputedValue,
     ToCss,
 )]
-pub struct BorderCornerRadius<L>(#[css(field_bound)] pub Size2D<L>);
+#[repr(C)]
+pub struct GenericBorderCornerRadius<L>(#[css(field_bound)] pub Size2D<L>);
+
+pub use self::GenericBorderCornerRadius as BorderCornerRadius;
 
 impl<L> BorderCornerRadius<L> {
     /// Trivially create a `BorderCornerRadius`.
@@ -77,6 +80,7 @@ impl<L> BorderCornerRadius<L> {
     ToComputedValue,
     ToCss,
 )]
+#[repr(transparent)]
 pub struct BorderSpacing<L>(#[css(field_bound)] pub Size2D<L>);
 
 impl<L> BorderSpacing<L> {
@@ -101,17 +105,20 @@ impl<L> BorderSpacing<L> {
     ToAnimatedValue,
     ToComputedValue,
 )]
-pub struct BorderRadius<LengthPercentage> {
+#[repr(C)]
+pub struct GenericBorderRadius<LengthPercentage> {
     /// The top left radius.
-    pub top_left: BorderCornerRadius<LengthPercentage>,
+    pub top_left: GenericBorderCornerRadius<LengthPercentage>,
     /// The top right radius.
-    pub top_right: BorderCornerRadius<LengthPercentage>,
+    pub top_right: GenericBorderCornerRadius<LengthPercentage>,
     /// The bottom right radius.
-    pub bottom_right: BorderCornerRadius<LengthPercentage>,
+    pub bottom_right: GenericBorderCornerRadius<LengthPercentage>,
     /// The bottom left radius.
-    pub bottom_left: BorderCornerRadius<LengthPercentage>,
+    pub bottom_left: GenericBorderCornerRadius<LengthPercentage>,
 }
 
+pub use self::GenericBorderRadius as BorderRadius;
+
 impl<L> BorderRadius<L> {
     /// Returns a new `BorderRadius<L>`.
     #[inline]
diff --git a/components/style/values/generics/size.rs b/components/style/values/generics/size.rs
index c67d6e82781..28c1ed5a36b 100644
--- a/components/style/values/generics/size.rs
+++ b/components/style/values/generics/size.rs
@@ -25,6 +25,7 @@ use style_traits::{CssWriter, ParseError, ToCss};
     ToComputedValue,
 )]
 #[allow(missing_docs)]
+#[repr(C)]
 pub struct Size2D<L> {
     pub width: L,
     pub height: L,