Auto merge of #20124 - servo:perspective, r=emilio

Replace LengthOrNone by a specific type for the perspective property

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components/style/values/specified/box.rs

@@ -13,9 +13,10 @@ use style_traits::{CssWriter, ParseError, StyleParseErrorKind, ToCss};
 use values::CustomIdent;
 use values::KeyframesName;
 use values::generics::box_::AnimationIterationCount as GenericAnimationIterationCount;
+use values::generics::box_::Perspective as GenericPerspective;
 use values::generics::box_::VerticalAlign as GenericVerticalAlign;
 use values::specified::{AllowQuirks, Number};
-use values::specified::length::LengthOrPercentage;
+use values::specified::length::{LengthOrPercentage, NonNegativeLength};
 
 #[allow(missing_docs)]
 #[derive(Clone, Copy, Debug, Eq, Hash, MallocSizeOf, Parse, PartialEq, ToComputedValue, ToCss)]
@@ -588,3 +589,18 @@ impl Parse for Contain {
         }
     }
 }
+
+/// A specified value for the `perspective` property.
+pub type Perspective = GenericPerspective<NonNegativeLength>;
+
+impl Parse for Perspective {
+    fn parse<'i, 't>(
+        context: &ParserContext,
+        input: &mut Parser<'i, 't>
+    ) -> Result<Self, ParseError<'i>> {
+        if input.try(|i| i.expect_ident_matching("none")).is_ok() {
+            return Ok(GenericPerspective::None);
+        }
+        Ok(GenericPerspective::Length(NonNegativeLength::parse(context, input)?))
+    }
+}

components/style/values/specified/length.rs

@@ -17,7 +17,7 @@ use std::ops::{Add, Mul};
 use style_traits::{ParseError, StyleParseErrorKind};
 use style_traits::values::specified::AllowedNumericType;
 use super::{AllowQuirks, Number, ToComputedValue, Percentage};
-use values::{Auto, CSSFloat, Either, None_, Normal};
+use values::{Auto, CSSFloat, Either, Normal};
 use values::computed::{self, CSSPixelLength, Context, ExtremumLength};
 use values::generics::NonNegative;
 use values::specified::NonNegativeNumber;
@@ -640,21 +640,19 @@ impl Length {
     }
 }
 
-impl<T: Parse> Either<Length, T> {
-    /// Parse a non-negative length
-    #[inline]
-    pub fn parse_non_negative_length<'i, 't>(context: &ParserContext, input: &mut Parser<'i, 't>)
-                                             -> Result<Self, ParseError<'i>> {
-        if let Ok(v) = input.try(|input| T::parse(context, input)) {
-            return Ok(Either::Second(v));
-        }
-        Length::parse_internal(context, input, AllowedNumericType::NonNegative, AllowQuirks::No).map(Either::First)
-    }
-}
-
 /// A wrapper of Length, whose value must be >= 0.
 pub type NonNegativeLength = NonNegative<Length>;
 
+impl Parse for NonNegativeLength {
+    #[inline]
+    fn parse<'i, 't>(
+        context: &ParserContext,
+        input: &mut Parser<'i, 't>,
+    ) -> Result<Self, ParseError<'i>> {
+        Ok(NonNegative(Length::parse_non_negative(context, input)?))
+    }
+}
+
 impl From<NoCalcLength> for NonNegativeLength {
     #[inline]
     fn from(len: NoCalcLength) -> Self {
@@ -669,17 +667,6 @@ impl From<Length> for NonNegativeLength {
     }
 }
 
-impl<T: Parse> Parse for Either<NonNegativeLength, T> {
-    #[inline]
-    fn parse<'i, 't>(context: &ParserContext, input: &mut Parser<'i, 't>) -> Result<Self, ParseError<'i>> {
-        if let Ok(v) = input.try(|input| T::parse(context, input)) {
-            return Ok(Either::Second(v));
-        }
-        Length::parse_internal(context, input, AllowedNumericType::NonNegative, AllowQuirks::No)
-            .map(NonNegative::<Length>).map(Either::First)
-    }
-}
-
 impl NonNegativeLength {
     /// Returns a `zero` length.
     #[inline]
@@ -701,7 +688,10 @@ pub type NonNegativeLengthOrNormal = Either<NonNegativeLength, Normal>;
 pub type NonNegativeLengthOrAuto = Either<NonNegativeLength, Auto>;
 
 /// Either a NonNegativeLength or a NonNegativeNumber value.
-pub type NonNegativeLengthOrNumber = Either<NonNegativeLength, NonNegativeNumber>;
+///
+/// The order is important, because `0` must be parsed as the number `0` and not
+/// the length `0px`.
+pub type NonNegativeLengthOrNumber = Either<NonNegativeNumber, NonNegativeLength>;
 
 /// A length or a percentage value.
 #[allow(missing_docs)]
@@ -1072,9 +1062,6 @@ impl NonNegativeLengthOrPercentage {
     }
 }
 
-/// Either a `<length>` or the `none` keyword.
-pub type LengthOrNone = Either<Length, None_>;
-
 /// Either a `<length>` or the `normal` keyword.
 pub type LengthOrNormal = Either<Length, Normal>;
 

components/style/values/specified/mod.rs

@@ -39,8 +39,9 @@ pub use self::font::{FontSize, FontSizeAdjust, FontSynthesis, FontWeight, FontVa
 pub use self::font::{FontFamily, FontLanguageOverride, FontVariationSettings, FontVariantEastAsian};
 pub use self::font::{FontVariantLigatures, FontVariantNumeric, FontFeatureSettings};
 pub use self::font::{MozScriptLevel, MozScriptMinSize, MozScriptSizeMultiplier, XTextZoom, XLang};
-pub use self::box_::{AnimationIterationCount, AnimationName, Display, OverscrollBehavior, Contain};
-pub use self::box_::{OverflowClipBox, ScrollSnapType, TouchAction, VerticalAlign, WillChange};
+pub use self::box_::{AnimationIterationCount, AnimationName, Contain, Display};
+pub use self::box_::{OverflowClipBox, OverscrollBehavior, Perspective};
+pub use self::box_::{ScrollSnapType, TouchAction, VerticalAlign, WillChange};
 pub use self::color::{Color, ColorPropertyValue, RGBAColor};
 pub use self::counters::{Content, ContentItem, CounterIncrement, CounterReset};
 pub use self::effects::{BoxShadow, Filter, SimpleShadow};
@@ -51,7 +52,7 @@ pub use self::image::{ColorStop, EndingShape as GradientEndingShape, Gradient};
 pub use self::image::{GradientItem, GradientKind, Image, ImageLayer, MozImageRect};
 pub use self::inherited_box::ImageOrientation;
 pub use self::length::{AbsoluteLength, CalcLengthOrPercentage, CharacterWidth};
-pub use self::length::{FontRelativeLength, Length, LengthOrNone, LengthOrNumber};
+pub use self::length::{FontRelativeLength, Length, LengthOrNumber};
 pub use self::length::{LengthOrPercentage, LengthOrPercentageOrAuto};
 pub use self::length::{LengthOrPercentageOrNone, MaxLength, MozLength};
 pub use self::length::{NoCalcLength, ViewportPercentageLength};