Split the Length type (introduce NoCalcLength)

components/style/values/computed/length.rs

@@ -17,6 +17,45 @@ pub use super::image::{EndingShape as GradientShape, Gradient, GradientKind, Ima
 pub use super::image::{LengthOrKeyword, LengthOrPercentageOrKeyword};
 pub use values::specified::{Angle, BorderStyle, Time, UrlOrNone};
 
+impl ToComputedValue for specified::NoCalcLength {
+    type ComputedValue = Au;
+
+    #[inline]
+    fn to_computed_value(&self, context: &Context) -> Au {
+        match *self {
+            specified::NoCalcLength::Absolute(length) => length,
+            specified::NoCalcLength::FontRelative(length) =>
+                length.to_computed_value(context, /* use inherited */ false),
+            specified::NoCalcLength::ViewportPercentage(length) =>
+                length.to_computed_value(context.viewport_size()),
+            specified::NoCalcLength::ServoCharacterWidth(length) =>
+                length.to_computed_value(context.style().get_font().clone_font_size())
+        }
+    }
+
+    #[inline]
+    fn from_computed_value(computed: &Au) -> Self {
+        specified::NoCalcLength::Absolute(*computed)
+    }
+}
+
+impl ToComputedValue for specified::Length {
+    type ComputedValue = Au;
+
+    #[inline]
+    fn to_computed_value(&self, context: &Context) -> Au {
+        match *self {
+            specified::Length::NoCalc(l) => l.to_computed_value(context),
+            specified::Length::Calc(ref calc, range) => range.clamp(calc.to_computed_value(context).length()),
+        }
+    }
+
+    #[inline]
+    fn from_computed_value(computed: &Au) -> Self {
+        specified::Length::NoCalc(specified::NoCalcLength::from_computed_value(computed))
+    }
+}
+
 #[derive(Clone, PartialEq, Copy, Debug)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 #[allow(missing_docs)]

components/style/values/computed/mod.rs

@@ -121,30 +121,6 @@ impl ToComputedValue for specified::CSSColor {
 
 impl ComputedValueAsSpecified for specified::BorderStyle {}
 
-impl ToComputedValue for specified::Length {
-    type ComputedValue = Au;
-
-    #[inline]
-    fn to_computed_value(&self, context: &Context) -> Au {
-        match *self {
-            specified::Length::Absolute(length) => length,
-            specified::Length::Calc(ref calc, range) => range.clamp(calc.to_computed_value(context).length()),
-            specified::Length::FontRelative(length) =>
-                length.to_computed_value(context, /* use inherited */ false),
-            specified::Length::ViewportPercentage(length) =>
-                length.to_computed_value(context.viewport_size()),
-            specified::Length::ServoCharacterWidth(length) =>
-                length.to_computed_value(context.style().get_font().clone_font_size())
-        }
-    }
-
-    #[inline]
-    fn from_computed_value(computed: &Au) -> Self {
-        specified::Length::Absolute(*computed)
-    }
-}
-
-
 #[derive(Debug, PartialEq, Clone, Copy)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 #[allow(missing_docs)]

components/style/values/specified/length.rs

@@ -24,6 +24,14 @@ pub use super::image::{AngleOrCorner, ColorStop, EndingShape as GradientEndingSh
 pub use super::image::{GradientKind, HorizontalDirection, Image, LengthOrKeyword, LengthOrPercentageOrKeyword};
 pub use super::image::{SizeKeyword, VerticalDirection};
 
+const AU_PER_PX: CSSFloat = 60.;
+const AU_PER_IN: CSSFloat = AU_PER_PX * 96.;
+const AU_PER_CM: CSSFloat = AU_PER_IN / 2.54;
+const AU_PER_MM: CSSFloat = AU_PER_IN / 25.4;
+const AU_PER_Q: CSSFloat = AU_PER_MM / 4.;
+const AU_PER_PT: CSSFloat = AU_PER_IN / 72.;
+const AU_PER_PC: CSSFloat = AU_PER_PT * 12.;
+
 #[derive(Clone, PartialEq, Copy, Debug)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 /// A font relative length.
@@ -205,12 +213,12 @@ impl CharacterWidth {
     }
 }
 
-/// A length.
+/// A `<length>` without taking `calc` expressions into account
 ///
 /// https://drafts.csswg.org/css-values/#lengths
-#[derive(Clone, PartialEq, Debug)]
+#[derive(Clone, PartialEq, Copy, Debug)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-pub enum Length {
+pub enum NoCalcLength {
     /// An absolute length: https://drafts.csswg.org/css-values/#absolute-length
     Absolute(Au),  // application units
 
@@ -229,7 +237,96 @@ pub enum Length {
     /// This cannot be specified by the user directly and is only generated by
     /// `Stylist::synthesize_rules_for_legacy_attributes()`.
     ServoCharacterWidth(CharacterWidth),
+}
 
+impl HasViewportPercentage for NoCalcLength {
+    fn has_viewport_percentage(&self) -> bool {
+        match *self {
+            NoCalcLength::ViewportPercentage(_) => true,
+            _ => false,
+        }
+    }
+}
+
+impl ToCss for NoCalcLength {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+        match *self {
+            NoCalcLength::Absolute(length) => write!(dest, "{}px", length.to_f32_px()),
+            NoCalcLength::FontRelative(length) => length.to_css(dest),
+            NoCalcLength::ViewportPercentage(length) => length.to_css(dest),
+            /* This should only be reached from style dumping code */
+            NoCalcLength::ServoCharacterWidth(CharacterWidth(i)) => write!(dest, "CharWidth({})", i),
+        }
+    }
+}
+
+impl Mul<CSSFloat> for NoCalcLength {
+    type Output = NoCalcLength;
+
+    #[inline]
+    fn mul(self, scalar: CSSFloat) -> NoCalcLength {
+        match self {
+            NoCalcLength::Absolute(Au(v)) => NoCalcLength::Absolute(Au(((v as f32) * scalar) as i32)),
+            NoCalcLength::FontRelative(v) => NoCalcLength::FontRelative(v * scalar),
+            NoCalcLength::ViewportPercentage(v) => NoCalcLength::ViewportPercentage(v * scalar),
+            NoCalcLength::ServoCharacterWidth(_) => panic!("Can't multiply ServoCharacterWidth!"),
+        }
+    }
+}
+
+impl NoCalcLength {
+    /// https://drafts.csswg.org/css-fonts-3/#font-size-prop
+    pub fn from_str(s: &str) -> Option<NoCalcLength> {
+        Some(match_ignore_ascii_case! { s,
+            "xx-small" => NoCalcLength::Absolute(Au::from_px(FONT_MEDIUM_PX) * 3 / 5),
+            "x-small" => NoCalcLength::Absolute(Au::from_px(FONT_MEDIUM_PX) * 3 / 4),
+            "small" => NoCalcLength::Absolute(Au::from_px(FONT_MEDIUM_PX) * 8 / 9),
+            "medium" => NoCalcLength::Absolute(Au::from_px(FONT_MEDIUM_PX)),
+            "large" => NoCalcLength::Absolute(Au::from_px(FONT_MEDIUM_PX) * 6 / 5),
+            "x-large" => NoCalcLength::Absolute(Au::from_px(FONT_MEDIUM_PX) * 3 / 2),
+            "xx-large" => NoCalcLength::Absolute(Au::from_px(FONT_MEDIUM_PX) * 2),
+
+            // https://github.com/servo/servo/issues/3423#issuecomment-56321664
+            "smaller" => NoCalcLength::FontRelative(FontRelativeLength::Em(0.85)),
+            "larger" => NoCalcLength::FontRelative(FontRelativeLength::Em(1.2)),
+            _ => return None
+        })
+    }
+
+    /// Parse a given absolute or relative dimension.
+    pub fn parse_dimension(value: CSSFloat, unit: &str) -> Result<NoCalcLength, ()> {
+        match_ignore_ascii_case! { unit,
+            "px" => Ok(NoCalcLength::Absolute(Au((value * AU_PER_PX) as i32))),
+            "in" => Ok(NoCalcLength::Absolute(Au((value * AU_PER_IN) as i32))),
+            "cm" => Ok(NoCalcLength::Absolute(Au((value * AU_PER_CM) as i32))),
+            "mm" => Ok(NoCalcLength::Absolute(Au((value * AU_PER_MM) as i32))),
+            "q" => Ok(NoCalcLength::Absolute(Au((value * AU_PER_Q) as i32))),
+            "pt" => Ok(NoCalcLength::Absolute(Au((value * AU_PER_PT) as i32))),
+            "pc" => Ok(NoCalcLength::Absolute(Au((value * AU_PER_PC) as i32))),
+            // font-relative
+            "em" => Ok(NoCalcLength::FontRelative(FontRelativeLength::Em(value))),
+            "ex" => Ok(NoCalcLength::FontRelative(FontRelativeLength::Ex(value))),
+            "ch" => Ok(NoCalcLength::FontRelative(FontRelativeLength::Ch(value))),
+            "rem" => Ok(NoCalcLength::FontRelative(FontRelativeLength::Rem(value))),
+            // viewport percentages
+            "vw" => Ok(NoCalcLength::ViewportPercentage(ViewportPercentageLength::Vw(value))),
+            "vh" => Ok(NoCalcLength::ViewportPercentage(ViewportPercentageLength::Vh(value))),
+            "vmin" => Ok(NoCalcLength::ViewportPercentage(ViewportPercentageLength::Vmin(value))),
+            "vmax" => Ok(NoCalcLength::ViewportPercentage(ViewportPercentageLength::Vmax(value))),
+            _ => Err(())
+        }
+    }
+}
+
+/// An extension to `NoCalcLength` to parse `calc` expressions.
+/// This is commonly used for the `<length>` values.
+///
+/// https://drafts.csswg.org/css-values/#lengths
+#[derive(Clone, PartialEq, Debug)]
+#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+pub enum Length {
+    /// The `NoCalcLength` type that cannot parse `calc`
+    NoCalc(NoCalcLength),
     /// A calc expression.
     ///
     /// https://drafts.csswg.org/css-values/#calc-notation
@@ -242,9 +339,8 @@ pub enum Length {
 impl HasViewportPercentage for Length {
     fn has_viewport_percentage(&self) -> bool {
         match *self {
-            Length::ViewportPercentage(_) => true,
+            Length::NoCalc(ref inner) => inner.has_viewport_percentage(),
             Length::Calc(ref calc, _) => calc.has_viewport_percentage(),
-            _ => false
         }
     }
 }
@@ -252,12 +348,8 @@ impl HasViewportPercentage for Length {
 impl ToCss for Length {
     fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
         match *self {
-            Length::Absolute(length) => write!(dest, "{}px", length.to_f32_px()),
+            Length::NoCalc(ref inner) => inner.to_css(dest),
-            Length::FontRelative(length) => length.to_css(dest),
-            Length::ViewportPercentage(length) => length.to_css(dest),
             Length::Calc(ref calc, _) => calc.to_css(dest),
-            /* This should only be reached from style dumping code */
-            Length::ServoCharacterWidth(CharacterWidth(i)) => write!(dest, "CharWidth({})", i),
         }
     }
 }
@@ -268,11 +360,8 @@ impl Mul<CSSFloat> for Length {
     #[inline]
     fn mul(self, scalar: CSSFloat) -> Length {
         match self {
-            Length::Absolute(Au(v)) => Length::Absolute(Au(((v as f32) * scalar) as i32)),
+            Length::NoCalc(inner) => Length::NoCalc(inner * scalar),
-            Length::FontRelative(v) => Length::FontRelative(v * scalar),
-            Length::ViewportPercentage(v) => Length::ViewportPercentage(v * scalar),
             Length::Calc(..) => panic!("Can't multiply Calc!"),
-            Length::ServoCharacterWidth(_) => panic!("Can't multiply ServoCharacterWidth!"),
         }
     }
 }
@@ -305,31 +394,15 @@ impl Mul<CSSFloat> for ViewportPercentageLength {
     }
 }
 
-const AU_PER_PX: CSSFloat = 60.;
-const AU_PER_IN: CSSFloat = AU_PER_PX * 96.;
-const AU_PER_CM: CSSFloat = AU_PER_IN / 2.54;
-const AU_PER_MM: CSSFloat = AU_PER_IN / 25.4;
-const AU_PER_Q: CSSFloat = AU_PER_MM / 4.;
-const AU_PER_PT: CSSFloat = AU_PER_IN / 72.;
-const AU_PER_PC: CSSFloat = AU_PER_PT * 12.;
-
 impl Length {
     /// https://drafts.csswg.org/css-fonts-3/#font-size-prop
     pub fn from_str(s: &str) -> Option<Length> {
-        Some(match_ignore_ascii_case! { s,
+        NoCalcLength::from_str(s).map(Length::NoCalc)
-            "xx-small" => Length::Absolute(Au::from_px(FONT_MEDIUM_PX) * 3 / 5),
+    }
-            "x-small" => Length::Absolute(Au::from_px(FONT_MEDIUM_PX) * 3 / 4),
-            "small" => Length::Absolute(Au::from_px(FONT_MEDIUM_PX) * 8 / 9),
-            "medium" => Length::Absolute(Au::from_px(FONT_MEDIUM_PX)),
-            "large" => Length::Absolute(Au::from_px(FONT_MEDIUM_PX) * 6 / 5),
-            "x-large" => Length::Absolute(Au::from_px(FONT_MEDIUM_PX) * 3 / 2),
-            "xx-large" => Length::Absolute(Au::from_px(FONT_MEDIUM_PX) * 2),
 
-            // https://github.com/servo/servo/issues/3423#issuecomment-56321664
+    /// Parse a given absolute or relative dimension.
-            "smaller" => Length::FontRelative(FontRelativeLength::Em(0.85)),
+    pub fn parse_dimension(value: CSSFloat, unit: &str) -> Result<Length, ()> {
-            "larger" => Length::FontRelative(FontRelativeLength::Em(1.2)),
+        NoCalcLength::parse_dimension(value, unit).map(Length::NoCalc)
-            _ => return None
-        })
     }
 
     #[inline]
@@ -352,34 +425,10 @@ impl Length {
         Length::parse_internal(input, AllowedNumericType::NonNegative)
     }
 
-    /// Parse a given absolute or relative dimension.
-    pub fn parse_dimension(value: CSSFloat, unit: &str) -> Result<Length, ()> {
-        match_ignore_ascii_case! { unit,
-            "px" => Ok(Length::from_px(value)),
-            "in" => Ok(Length::Absolute(Au((value * AU_PER_IN) as i32))),
-            "cm" => Ok(Length::Absolute(Au((value * AU_PER_CM) as i32))),
-            "mm" => Ok(Length::Absolute(Au((value * AU_PER_MM) as i32))),
-            "q" => Ok(Length::Absolute(Au((value * AU_PER_Q) as i32))),
-            "pt" => Ok(Length::Absolute(Au((value * AU_PER_PT) as i32))),
-            "pc" => Ok(Length::Absolute(Au((value * AU_PER_PC) as i32))),
-            // font-relative
-            "em" => Ok(Length::FontRelative(FontRelativeLength::Em(value))),
-            "ex" => Ok(Length::FontRelative(FontRelativeLength::Ex(value))),
-            "ch" => Ok(Length::FontRelative(FontRelativeLength::Ch(value))),
-            "rem" => Ok(Length::FontRelative(FontRelativeLength::Rem(value))),
-            // viewport percentages
-            "vw" => Ok(Length::ViewportPercentage(ViewportPercentageLength::Vw(value))),
-            "vh" => Ok(Length::ViewportPercentage(ViewportPercentageLength::Vh(value))),
-            "vmin" => Ok(Length::ViewportPercentage(ViewportPercentageLength::Vmin(value))),
-            "vmax" => Ok(Length::ViewportPercentage(ViewportPercentageLength::Vmax(value))),
-            _ => Err(())
-        }
-    }
-
     /// Get an absolute length from a px values.
     #[inline]
     pub fn from_px(px_value: CSSFloat) -> Length {
-        Length::Absolute(Au((px_value * AU_PER_PX) as i32))
+        Length::NoCalc(NoCalcLength::Absolute(Au((px_value * AU_PER_PX) as i32)))
     }
 
     /// Extract inner length without a clone, replacing it with a 0 Au
@@ -648,9 +697,9 @@ impl CalcLengthOrPercentage {
             match value {
                 SimplifiedValueNode::Percentage(p) =>
                     percentage = Some(percentage.unwrap_or(0.) + p),
-                SimplifiedValueNode::Length(Length::Absolute(Au(au))) =>
+                SimplifiedValueNode::Length(NoCalcLength::Absolute(Au(au))) =>
                     absolute = Some(absolute.unwrap_or(0) + au),
-                SimplifiedValueNode::Length(Length::ViewportPercentage(v)) =>
+                SimplifiedValueNode::Length(NoCalcLength::ViewportPercentage(v)) =>
                     match v {
                         ViewportPercentageLength::Vw(val) =>
                             vw = Some(vw.unwrap_or(0.) + val),
@@ -661,7 +710,7 @@ impl CalcLengthOrPercentage {
                         ViewportPercentageLength::Vmax(val) =>
                             vmax = Some(vmax.unwrap_or(0.) + val),
                     },
-                SimplifiedValueNode::Length(Length::FontRelative(f)) =>
+                SimplifiedValueNode::Length(NoCalcLength::FontRelative(f)) =>
                     match f {
                         FontRelativeLength::Em(val) =>
                             em = Some(em.unwrap_or(0.) + val),

components/style/values/specified/mod.rs

@@ -26,7 +26,7 @@ pub use self::image::{GradientKind, HorizontalDirection, Image, LengthOrKeyword,
 pub use self::image::{SizeKeyword, VerticalDirection};
 pub use self::length::{FontRelativeLength, ViewportPercentageLength, CharacterWidth, Length, CalcLengthOrPercentage};
 pub use self::length::{Percentage, LengthOrNone, LengthOrNumber, LengthOrPercentage, LengthOrPercentageOrAuto};
-pub use self::length::{LengthOrPercentageOrNone, LengthOrPercentageOrAutoOrContent, CalcUnit};
+pub use self::length::{LengthOrPercentageOrNone, LengthOrPercentageOrAutoOrContent, NoCalcLength, CalcUnit};
 
 pub mod basic_shape;
 pub mod grid;
@@ -109,13 +109,14 @@ impl<'a> Mul<CSSFloat> for &'a SimplifiedSumNode {
 #[derive(Clone, Debug)]
 #[allow(missing_docs)]
 pub enum SimplifiedValueNode {
-    Length(Length),
+    Length(NoCalcLength),
     Angle(Angle),
     Time(Time),
     Percentage(CSSFloat),
     Number(CSSFloat),
     Sum(Box<SimplifiedSumNode>),
 }
+
 impl<'a> Mul<CSSFloat> for &'a SimplifiedValueNode {
     type Output = SimplifiedValueNode;