style: adding from-font support to text-underline-offset and text-decoration-thickness.

Differential Revision: https://phabricator.services.mozilla.com/D41476

components/style/properties/longhands/inherited_text.mako.rs

@@ -382,8 +382,8 @@ ${helpers.single_keyword(
 // text underline offset
 ${helpers.predefined_type(
     "text-underline-offset",
-    "LengthOrAuto",
-    "computed::LengthOrAuto::auto()",
+    "TextDecorationLength",
+    "generics::text::GenericTextDecorationLength::Auto",
     engines="gecko",
     animation_value_type="ComputedValue",
     gecko_pref="layout.css.text-underline-offset.enabled",

components/style/properties/longhands/text.mako.rs

@@ -71,10 +71,10 @@ ${helpers.predefined_type(
 
 ${helpers.predefined_type(
    "text-decoration-thickness",
-   "LengthOrAuto",
-   "computed::LengthOrAuto::auto()",
+   "TextDecorationLength",
+   "generics::text::GenericTextDecorationLength::Auto",
    engines="gecko",
-   initial_specified_value="specified::LengthOrAuto::auto()",
+   initial_specified_value="generics::text::GenericTextDecorationLength::Auto",
    animation_value_type="ComputedValue",
    gecko_pref="layout.css.text-decoration-thickness.enabled",
    spec="https://drafts.csswg.org/css-text-decor-4/#text-decoration-width-property"

components/style/values/computed/mod.rs

@@ -76,7 +76,7 @@ pub use self::svg::MozContextProperties;
 pub use self::svg::{SVGLength, SVGOpacity, SVGPaint, SVGPaintKind};
 pub use self::svg::{SVGPaintOrder, SVGStrokeDashArray, SVGWidth};
 pub use self::table::XSpan;
-pub use self::text::TextDecorationSkipInk;
+pub use self::text::{TextDecorationLength, TextDecorationSkipInk};
 pub use self::text::{InitialLetter, LetterSpacing, LineBreak, LineHeight};
 pub use self::text::{OverflowWrap, TextOverflow, WordBreak, WordSpacing};
 pub use self::text::{TextAlign, TextEmphasisPosition, TextEmphasisStyle};

components/style/values/computed/text.rs

@@ -10,7 +10,7 @@ use crate::values::computed::length::{Length, LengthPercentage};
 use crate::values::computed::{Context, NonNegativeLength, NonNegativeNumber, ToComputedValue};
 use crate::values::generics::text::InitialLetter as GenericInitialLetter;
 use crate::values::generics::text::LineHeight as GenericLineHeight;
-use crate::values::generics::text::Spacing;
+use crate::values::generics::text::{Spacing, GenericTextDecorationLength};
 use crate::values::specified::text::{self as specified, TextOverflowSide};
 use crate::values::specified::text::{TextEmphasisFillMode, TextEmphasisShapeKeyword};
 use crate::values::{CSSFloat, CSSInteger};
@@ -26,6 +26,9 @@ pub use crate::values::specified::{TextDecorationSkipInk, TextTransform};
 /// A computed value for the `initial-letter` property.
 pub type InitialLetter = GenericInitialLetter<CSSFloat, CSSInteger>;
 
+/// Implements type for `text-underline-offset` and `text-decoration-thickness` properties
+pub type TextDecorationLength = GenericTextDecorationLength<Length>;
+
 /// A computed value for the `letter-spacing` property.
 #[repr(transparent)]
 #[derive(

components/style/values/generics/text.rs

@@ -122,3 +122,33 @@ impl<N, L> LineHeight<N, L> {
         LineHeight::Normal
     }
 }
+
+/// Implements type for text-underline-offset and text-decoration-thickness
+/// which take the grammar of auto | from-font | <length>
+///
+/// https://drafts.csswg.org/css-text-decor-4/
+#[repr(C, u8)]
+#[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
+#[derive(
+    Animate,
+    Clone,
+    Copy,
+    ComputeSquaredDistance,
+    ToAnimatedZero,
+    Debug,
+    Eq,
+    MallocSizeOf,
+    Parse,
+    PartialEq,
+    SpecifiedValueInfo,
+    ToComputedValue,
+    ToCss,
+    ToResolvedValue,
+    ToShmem,
+)]
+#[allow(missing_docs)]
+pub enum GenericTextDecorationLength<L> {
+    Length(L),
+    Auto,
+    FromFont,
+}

components/style/values/specified/mod.rs

@@ -82,7 +82,7 @@ pub use self::table::XSpan;
 pub use self::text::{InitialLetter, LetterSpacing, LineBreak, LineHeight, TextAlign};
 pub use self::text::{OverflowWrap, TextEmphasisPosition, TextEmphasisStyle, WordBreak};
 pub use self::text::{TextAlignKeyword, TextDecorationLine, TextOverflow, WordSpacing};
-pub use self::text::{TextDecorationSkipInk, TextTransform};
+pub use self::text::{TextDecorationLength, TextDecorationSkipInk, TextTransform};
 pub use self::time::Time;
 pub use self::transform::{Rotate, Scale, Transform};
 pub use self::transform::{TransformOrigin, TransformStyle, Translate};

components/style/values/specified/text.rs

@@ -12,7 +12,7 @@ use crate::values::computed::text::TextOverflow as ComputedTextOverflow;
 use crate::values::computed::{Context, ToComputedValue};
 use crate::values::generics::text::InitialLetter as GenericInitialLetter;
 use crate::values::generics::text::LineHeight as GenericLineHeight;
-use crate::values::generics::text::Spacing;
+use crate::values::generics::text::{Spacing, GenericTextDecorationLength};
 use crate::values::specified::length::NonNegativeLengthPercentage;
 use crate::values::specified::length::{FontRelativeLength, Length};
 use crate::values::specified::length::{LengthPercentage, NoCalcLength};
@@ -1039,3 +1039,20 @@ pub enum TextDecorationSkipInk {
     Auto,
     None,
 }
+
+/// Implements type for `text-underline-offset` and `text-decoration-thickness` properties
+pub type TextDecorationLength = GenericTextDecorationLength<Length>;
+
+impl TextDecorationLength {
+    /// `Auto` value.
+    #[inline]
+    pub fn auto() -> Self {
+        GenericTextDecorationLength::Auto
+    }
+
+    /// Whether this is the `Auto` value.
+    #[inline]
+    pub fn is_auto(&self) -> bool {
+        matches!(*self,  GenericTextDecorationLength::Auto)
+    }
+}