style: Refactor GenericGradient for conic-gradient support.

Differential Revision: https://phabricator.services.mozilla.com/D62923

components/style/values/generics/image.rs

@@ -51,7 +51,7 @@ pub use self::GenericImage as Image;
 /// <https://drafts.csswg.org/css-images/#gradients>
 #[derive(Clone, Debug, MallocSizeOf, PartialEq, ToComputedValue, ToResolvedValue, ToShmem)]
 #[repr(C)]
-pub struct GenericGradient<
+pub enum GenericGradient<
     LineDirection,
     LengthPercentage,
     NonNegativeLength,
@@ -59,19 +59,30 @@ pub struct GenericGradient<
     Position,
     Color,
 > {
-    /// Gradients can be linear or radial.
-    pub kind: GenericGradientKind<
-        LineDirection,
-        NonNegativeLength,
-        NonNegativeLengthPercentage,
-        Position,
-    >,
-    /// The color stops and interpolation hints.
-    pub items: crate::OwnedSlice<GenericGradientItem<Color, LengthPercentage>>,
-    /// True if this is a repeating gradient.
-    pub repeating: bool,
-    /// Compatibility mode.
-    pub compat_mode: GradientCompatMode,
+    /// A linear gradient.
+    Linear {
+        /// Line direction
+        direction: LineDirection,
+        /// The color stops and interpolation hints.
+        items: crate::OwnedSlice<GenericGradientItem<Color, LengthPercentage>>,
+        /// True if this is a repeating gradient.
+        repeating: bool,
+        /// Compatibility mode.
+        compat_mode: GradientCompatMode,
+    },
+    /// A radial gradient.
+    Radial {
+        /// Shape of gradient
+        shape: GenericEndingShape<NonNegativeLength, NonNegativeLengthPercentage>,
+        /// Center of gradient
+        position: Position,
+        /// The color stops and interpolation hints.
+        items: crate::OwnedSlice<GenericGradientItem<Color, LengthPercentage>>,
+        /// True if this is a repeating gradient.
+        repeating: bool,
+        /// Compatibility mode.
+        compat_mode: GradientCompatMode,
+    },
 }
 
 pub use self::GenericGradient as Gradient;
@@ -88,26 +99,6 @@ pub enum GradientCompatMode {
     Moz,
 }
 
-/// A gradient kind.
-#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToComputedValue, ToResolvedValue, ToShmem)]
-#[repr(C, u8)]
-pub enum GenericGradientKind<
-    LineDirection,
-    NonNegativeLength,
-    NonNegativeLengthPercentage,
-    Position,
-> {
-    /// A linear gradient.
-    Linear(LineDirection),
-    /// A radial gradient.
-    Radial(
-        GenericEndingShape<NonNegativeLength, NonNegativeLengthPercentage>,
-        Position,
-    ),
-}
-
-pub use self::GenericGradientKind as GradientKind;
-
 /// A radial gradient's ending shape.
 #[derive(
     Clone, Copy, Debug, MallocSizeOf, PartialEq, ToComputedValue, ToCss, ToResolvedValue, ToShmem,
@@ -330,32 +321,39 @@ where
     where
         W: Write,
     {
-        match self.compat_mode {
+        let (compat_mode, repeating) = match *self {
+            Gradient::Linear { compat_mode, repeating, .. } => (compat_mode, repeating),
+            Gradient::Radial { compat_mode, repeating, .. } => (compat_mode, repeating),
+        };
+
+        match compat_mode {
             GradientCompatMode::WebKit => dest.write_str("-webkit-")?,
             GradientCompatMode::Moz => dest.write_str("-moz-")?,
             _ => {},
         }
 
-        if self.repeating {
+        if repeating {
             dest.write_str("repeating-")?;
         }
-        dest.write_str(self.kind.label())?;
-        dest.write_str("-gradient(")?;
-        let mut skip_comma = match self.kind {
-            GradientKind::Linear(ref direction) if direction.points_downwards(self.compat_mode) => {
-                true
+
+        let (items, mut skip_comma) = match *self {
+            Gradient::Linear { ref direction, compat_mode, ref items, .. } => {
+                dest.write_str("linear-gradient(")?;
+                if !direction.points_downwards(compat_mode) {
+                    direction.to_css(dest, compat_mode)?;
+                    (items, false)
+                } else {
+                    (items, true)
+                }
             },
-            GradientKind::Linear(ref direction) => {
-                direction.to_css(dest, self.compat_mode)?;
-                false
-            },
-            GradientKind::Radial(ref shape, ref position) => {
+            Gradient::Radial { ref shape, ref position, compat_mode, ref items, .. } => {
+                dest.write_str("radial-gradient(")?;
                 let omit_shape = match *shape {
                     EndingShape::Ellipse(Ellipse::Extent(ShapeExtent::Cover)) |
                     EndingShape::Ellipse(Ellipse::Extent(ShapeExtent::FarthestCorner)) => true,
                     _ => false,
                 };
-                if self.compat_mode == GradientCompatMode::Modern {
+                if compat_mode == GradientCompatMode::Modern {
                     if !omit_shape {
                         shape.to_css(dest)?;
                         dest.write_str(" ")?;
@@ -369,10 +367,10 @@ where
                         shape.to_css(dest)?;
                     }
                 }
-                false
+                (items, false)
             },
         };
-        for item in &*self.items {
+        for item in &**items {
             if !skip_comma {
                 dest.write_str(", ")?;
             }
@@ -383,15 +381,6 @@ where
     }
 }
 
-impl<D, L, LoP, P> GradientKind<D, L, LoP, P> {
-    fn label(&self) -> &str {
-        match *self {
-            GradientKind::Linear(..) => "linear",
-            GradientKind::Radial(..) => "radial",
-        }
-    }
-}
-
 /// The direction of a linear gradient.
 pub trait LineDirection {
     /// Whether this direction points towards, and thus can be omitted.

components/style/values/specified/image.rs

@@ -70,10 +70,6 @@ impl SpecifiedValueInfo for Gradient {
     }
 }
 
-/// A specified gradient kind.
-pub type GradientKind =
-    generic::GradientKind<LineDirection, NonNegativeLength, NonNegativeLengthPercentage, Position>;
-
 /// A specified gradient line direction.
 ///
 /// FIXME(emilio): This should be generic over Angle.
@@ -245,25 +241,12 @@ impl Parse for Gradient {
             }
         };
 
-        let (kind, items) = input.parse_nested_block(|i| {
-            let shape = match shape {
-                Shape::Linear => GradientKind::parse_linear(context, i, &mut compat_mode)?,
-                Shape::Radial => GradientKind::parse_radial(context, i, &mut compat_mode)?,
-            };
-            let items = generic::GradientItem::parse_comma_separated(context, i)?;
-            Ok((shape, items))
-        })?;
-
-        if items.len() < 2 {
-            return Err(input.new_custom_error(StyleParseErrorKind::UnspecifiedError));
-        }
-
-        Ok(Gradient {
-            items,
-            repeating,
-            kind,
-            compat_mode,
-        })
+        Ok(input.parse_nested_block(|i| {
+            Ok(match shape {
+                Shape::Linear => Self::parse_linear(context, i, repeating, &mut compat_mode)?,
+                Shape::Radial => Self::parse_radial(context, i, repeating, compat_mode)?,
+            })
+        })?)
     }
 }
 
@@ -383,16 +366,21 @@ impl Gradient {
         let ident = input.expect_ident_cloned()?;
         input.expect_comma()?;
 
-        let (kind, reverse_stops) = match_ignore_ascii_case! { &ident,
+        Ok(match_ignore_ascii_case! { &ident,
             "linear" => {
                 let first = Point::parse(context, input)?;
                 input.expect_comma()?;
                 let second = Point::parse(context, input)?;
 
                 let direction = LineDirection::from_points(first, second);
-                let kind = generic::GradientKind::Linear(direction);
+                let items = Gradient::parse_webkit_gradient_stops(context, input, false)?;
 
-                (kind, false)
+                generic::Gradient::Linear {
+                    direction,
+                    items,
+                    repeating: false,
+                    compat_mode: GradientCompatMode::Modern,
+                }
             },
             "radial" => {
                 let first_point = Point::parse(context, input)?;
@@ -412,16 +400,28 @@ impl Gradient {
                 let rad = Circle::Radius(NonNegative(Length::from_px(radius.value)));
                 let shape = generic::EndingShape::Circle(rad);
                 let position: Position = point.into();
+                let items = Gradient::parse_webkit_gradient_stops(context, input, reverse_stops)?;
 
-                let kind = generic::GradientKind::Radial(shape, position);
-                (kind, reverse_stops)
+                generic::Gradient::Radial {
+                    shape,
+                    position,
+                    items,
+                    repeating: false,
+                    compat_mode: GradientCompatMode::Modern,
+                }
             },
             _ => {
                 let e = SelectorParseErrorKind::UnexpectedIdent(ident.clone());
                 return Err(input.new_custom_error(e));
             },
-        };
+        })
+    }
 
+    fn parse_webkit_gradient_stops<'i, 't>(
+        context: &ParserContext,
+        input: &mut Parser<'i, 't>,
+        reverse_stops: bool,
+    ) -> Result<crate::OwnedSlice<generic::GradientItem<Color, LengthPercentage>>, ParseError<'i>> {
         let mut items = input
             .try(|i| {
                 i.expect_comma()?;
@@ -500,22 +500,29 @@ impl Gradient {
                 }
             })
         }
-
-        Ok(generic::Gradient {
-            kind,
-            items: items.into(),
-            repeating: false,
-            compat_mode: GradientCompatMode::Modern,
-        })
+        Ok(items.into())
+    }
+
+    /// Not used for -webkit-gradient syntax.
+    fn parse_stops<'i, 't>(
+        context: &ParserContext,
+        input: &mut Parser<'i, 't>,
+    ) -> Result<crate::OwnedSlice<generic::GradientItem<Color, LengthPercentage>>, ParseError<'i>> {
+        let items = generic::GradientItem::parse_comma_separated(context, input)?;
+
+        if items.len() < 2 {
+            return Err(input.new_custom_error(StyleParseErrorKind::UnspecifiedError));
+        }
+
+        Ok(items)
     }
-}
 
-impl GradientKind {
     /// Parses a linear gradient.
     /// GradientCompatMode can change during `-moz-` prefixed gradient parsing if it come across a `to` keyword.
     fn parse_linear<'i, 't>(
         context: &ParserContext,
         input: &mut Parser<'i, 't>,
+        repeating: bool,
         compat_mode: &mut GradientCompatMode,
     ) -> Result<Self, ParseError<'i>> {
         let direction = if let Ok(d) = input.try(|i| LineDirection::parse(context, i, compat_mode))
@@ -523,23 +530,33 @@ impl GradientKind {
             input.expect_comma()?;
             d
         } else {
-            match *compat_mode {
+            match compat_mode {
                 GradientCompatMode::Modern => {
                     LineDirection::Vertical(VerticalPositionKeyword::Bottom)
                 },
                 _ => LineDirection::Vertical(VerticalPositionKeyword::Top),
             }
         };
-        Ok(generic::GradientKind::Linear(direction))
+        let items = Gradient::parse_stops(context, input)?;
+
+        Ok(Gradient::Linear {
+            direction,
+            items,
+            repeating,
+            compat_mode: *compat_mode,
+        })
     }
+
+    /// Parses a radial gradient.
     fn parse_radial<'i, 't>(
         context: &ParserContext,
         input: &mut Parser<'i, 't>,
-        compat_mode: &mut GradientCompatMode,
+        repeating: bool,
+        compat_mode: GradientCompatMode,
     ) -> Result<Self, ParseError<'i>> {
-        let (shape, position) = match *compat_mode {
+        let (shape, position) = match compat_mode {
             GradientCompatMode::Modern => {
-                let shape = input.try(|i| EndingShape::parse(context, i, *compat_mode));
+                let shape = input.try(|i| EndingShape::parse(context, i, compat_mode));
                 let position = input.try(|i| {
                     i.expect_ident_matching("at")?;
                     Position::parse(context, i)
@@ -552,7 +569,7 @@ impl GradientKind {
                     if position.is_ok() {
                         i.expect_comma()?;
                     }
-                    EndingShape::parse(context, i, *compat_mode)
+                    EndingShape::parse(context, i, compat_mode)
                 });
                 (shape, position.ok())
             },
@@ -567,7 +584,16 @@ impl GradientKind {
         });
 
         let position = position.unwrap_or(Position::center());
-        Ok(generic::GradientKind::Radial(shape, position))
+
+        let items = Gradient::parse_stops(context, input)?;
+
+        Ok(Gradient::Radial {
+            shape,
+            position,
+            items,
+            repeating,
+            compat_mode,
+        })
     }
 }
 

components/style/values/specified/length.rs

@@ -29,7 +29,7 @@ use style_traits::values::specified::AllowedNumericType;
 use style_traits::{ParseError, SpecifiedValueInfo, StyleParseErrorKind};
 
 pub use super::image::{EndingShape as GradientEndingShape, Gradient};
-pub use super::image::{GradientKind, Image};
+pub use super::image::Image;
 pub use crate::values::specified::calc::CalcLengthPercentage;
 
 /// Number of app units per pixel

components/style/values/specified/mod.rs

@@ -56,7 +56,7 @@ pub use self::font::{FontVariantAlternates, FontWeight};
 pub use self::font::{FontVariantEastAsian, FontVariationSettings};
 pub use self::font::{MozScriptLevel, MozScriptMinSize, MozScriptSizeMultiplier, XLang, XTextZoom};
 pub use self::image::{EndingShape as GradientEndingShape, Gradient};
-pub use self::image::{GradientKind, Image, MozImageRect};
+pub use self::image::{Image, MozImageRect};
 pub use self::length::{AbsoluteLength, CalcLengthPercentage, CharacterWidth};
 pub use self::length::{FontRelativeLength, Length, LengthOrNumber, NonNegativeLengthOrNumber};
 pub use self::length::{LengthOrAuto, LengthPercentage, LengthPercentageOrAuto};