Add support for MaxLength

This builds on the ExtremumLength type from the previous commit.

components/style/gecko/values.rs

@@ -14,7 +14,7 @@ use std::cmp::max;
 use values::{Auto, Either, ExtremumLength, None_, Normal};
 use values::computed::{Angle, LengthOrPercentageOrNone, Number};
 use values::computed::{LengthOrPercentage, LengthOrPercentageOrAuto};
-use values::computed::MinLength;
+use values::computed::{MaxLength, MinLength};
 use values::computed::basic_shape::ShapeRadius;
 use values::specified::grid::{TrackBreadth, TrackKeyword};
 
@@ -321,6 +321,25 @@ impl GeckoStyleCoordConvertible for MinLength {
     }
 }
 
+impl GeckoStyleCoordConvertible for MaxLength {
+    fn to_gecko_style_coord<T: CoordDataMut>(&self, coord: &mut T) {
+        match *self {
+            MaxLength::LengthOrPercentage(ref lop) => lop.to_gecko_style_coord(coord),
+            MaxLength::None => coord.set_value(CoordDataValue::None),
+            MaxLength::ExtremumLength(ref e) => e.to_gecko_style_coord(coord),
+        }
+    }
+
+    fn from_gecko_style_coord<T: CoordData>(coord: &T) -> Option<Self> {
+        LengthOrPercentage::from_gecko_style_coord(coord).map(MaxLength::LengthOrPercentage)
+            .or_else(|| ExtremumLength::from_gecko_style_coord(coord).map(MaxLength::ExtremumLength))
+            .or_else(|| match coord.as_value() {
+                CoordDataValue::None => Some(MaxLength::None),
+                _ => None,
+            })
+    }
+}
+
 /// Convert a given RGBA value to `nscolor`.
 pub fn convert_rgba_to_nscolor(rgba: &RGBA) -> u32 {
     ((rgba.alpha as u32) << 24) |

components/style/properties/gecko.mako.rs

@@ -635,6 +635,7 @@ impl Debug for ${style_struct.gecko_struct_name} {
         "LengthOrPercentageOrAuto": impl_style_coord,
         "LengthOrPercentageOrNone": impl_style_coord,
         "LengthOrNone": impl_style_coord,
+        "MaxLength": impl_style_coord,
         "MinLength": impl_style_coord,
         "Number": impl_simple,
         "Opacity": impl_simple,

components/style/properties/helpers/animated_properties.mako.rs

@@ -33,7 +33,7 @@ use values::Either;
 use values::computed::{Angle, LengthOrPercentageOrAuto, LengthOrPercentageOrNone};
 use values::computed::{BorderRadiusSize, ClipRect, LengthOrNone};
 use values::computed::{CalcLengthOrPercentage, Context, LengthOrPercentage};
-use values::computed::MinLength;
+use values::computed::{MaxLength, MinLength};
 use values::computed::position::{HorizontalPosition, Position, VerticalPosition};
 use values::computed::ToComputedValue;
 use values::specified::Angle as SpecifiedAngle;
@@ -645,6 +645,20 @@ impl Interpolate for MinLength {
     }
 }
 
+/// https://drafts.csswg.org/css-transitions/#animtype-lpcalc
+impl Interpolate for MaxLength {
+    #[inline]
+    fn interpolate(&self, other: &Self, progress: f64) -> Result<Self, ()> {
+        match (*self, *other) {
+            (MaxLength::LengthOrPercentage(ref this),
+             MaxLength::LengthOrPercentage(ref other)) => {
+                this.interpolate(other, progress).map(MaxLength::LengthOrPercentage)
+            }
+            _ => Err(()),
+        }
+    }
+}
+
 /// https://drafts.csswg.org/css-transitions/#animtype-number
 /// https://drafts.csswg.org/css-transitions/#animtype-length
 impl Interpolate for LineHeight {

components/style/properties/longhand/position.mako.rs

@@ -237,13 +237,21 @@ ${helpers.predefined_type("flex-basis",
     % endif
 
     // max-width, max-height, max-block-size, max-inline-size
-    ${helpers.predefined_type("max-%s" % size,
-                              "LengthOrPercentageOrNone",
-                              "computed::LengthOrPercentageOrNone::None",
-                              "parse_non_negative",
-                              needs_context=False,
-                              spec=spec % ("max-%s" % size),
-                              animatable=True, logical = logical)}
+    % if product == "gecko":
+        ${helpers.predefined_type("max-%s" % size,
+                                  "MaxLength",
+                                  "computed::MaxLength::None",
+                                  spec=spec % ("max-%s" % size),
+                                  animatable=True, logical = logical)}
+    % else:
+        ${helpers.predefined_type("max-%s" % size,
+                                  "LengthOrPercentageOrNone",
+                                  "computed::LengthOrPercentageOrNone::None",
+                                  "parse_non_negative",
+                                  needs_context=False,
+                                  spec=spec % ("max-%s" % size),
+                                  animatable=True, logical = logical)}
+    % endif
 % endfor
 
 ${helpers.single_keyword("box-sizing",

components/style/values/computed/length.rs

@@ -601,3 +601,58 @@ impl ToCss for MinLength {
         }
     }
 }
+
+/// A value suitable for a `max-width` or `max-height` property.
+/// See specified/values/length.rs for more details.
+#[derive(Debug, Copy, Clone, PartialEq)]
+#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[allow(missing_docs)]
+pub enum MaxLength {
+    LengthOrPercentage(LengthOrPercentage),
+    None,
+    ExtremumLength(ExtremumLength),
+}
+
+impl ToComputedValue for specified::MaxLength {
+    type ComputedValue = MaxLength;
+
+    #[inline]
+    fn to_computed_value(&self, context: &Context) -> MaxLength {
+        match *self {
+            specified::MaxLength::LengthOrPercentage(ref lop) => {
+                MaxLength::LengthOrPercentage(lop.to_computed_value(context))
+            }
+            specified::MaxLength::None => {
+                MaxLength::None
+            }
+            specified::MaxLength::ExtremumLength(ref ext) => {
+                MaxLength::ExtremumLength(ext.clone())
+            }
+        }
+    }
+
+    #[inline]
+    fn from_computed_value(computed: &MaxLength) -> Self {
+        match *computed {
+            MaxLength::None =>
+                specified::MaxLength::None,
+            MaxLength::LengthOrPercentage(ref lop) =>
+                specified::MaxLength::LengthOrPercentage(specified::LengthOrPercentage::from_computed_value(&lop)),
+            MaxLength::ExtremumLength(ref ext) =>
+                specified::MaxLength::ExtremumLength(ext.clone()),
+        }
+    }
+}
+
+impl ToCss for MaxLength {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+        match *self {
+            MaxLength::LengthOrPercentage(lop) =>
+                lop.to_css(dest),
+            MaxLength::None =>
+                dest.write_str("none"),
+            MaxLength::ExtremumLength(ext) =>
+                ext.to_css(dest),
+        }
+    }
+}

components/style/values/computed/mod.rs

@@ -23,7 +23,7 @@ pub use super::specified::{Angle, BorderStyle, GridLine, Time, UrlOrNone};
 pub use super::specified::url::{SpecifiedUrl, UrlExtraData};
 pub use self::length::{CalcLengthOrPercentage, Length, LengthOrNumber, LengthOrPercentage, LengthOrPercentageOrAuto};
 pub use self::length::{LengthOrPercentageOrAutoOrContent, LengthOrPercentageOrNone, LengthOrNone};
-pub use self::length::MinLength;
+pub use self::length::{MaxLength, MinLength};
 pub use self::position::Position;
 
 pub mod basic_shape;

components/style/values/specified/length.rs

@@ -1353,3 +1353,49 @@ impl Parse for MinLength {
             })
     }
 }
+
+/// A value suitable for a `max-width` or `max-height` property.
+#[derive(Debug, Clone, PartialEq)]
+#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[allow(missing_docs)]
+pub enum MaxLength {
+    LengthOrPercentage(LengthOrPercentage),
+    None,
+    ExtremumLength(ExtremumLength),
+}
+
+impl HasViewportPercentage for MaxLength {
+    fn has_viewport_percentage(&self) -> bool {
+        match *self {
+            MaxLength::LengthOrPercentage(ref lop) => lop.has_viewport_percentage(),
+            _ => false
+        }
+    }
+}
+
+impl ToCss for MaxLength {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+        match *self {
+            MaxLength::LengthOrPercentage(ref lop) =>
+                lop.to_css(dest),
+            MaxLength::None =>
+                dest.write_str("none"),
+            MaxLength::ExtremumLength(ref ext) =>
+                ext.to_css(dest),
+        }
+    }
+}
+
+impl Parse for MaxLength {
+    fn parse(_context: &ParserContext, input: &mut Parser) -> Result<Self, ()> {
+        input.try(ExtremumLength::parse).map(MaxLength::ExtremumLength)
+            .or_else(|()| input.try(LengthOrPercentage::parse_non_negative).map(MaxLength::LengthOrPercentage))
+            .or_else(|()| {
+                match_ignore_ascii_case! { try!(input.expect_ident()),
+                    "none" =>
+                        Ok(MaxLength::None),
+                    _ => Err(())
+                }
+            })
+    }
+}

components/style/values/specified/mod.rs

@@ -30,7 +30,7 @@ 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, NoCalcLength, CalcUnit};
-pub use self::length::MinLength;
+pub use self::length::{MaxLength, MinLength};
 pub use self::position::{HorizontalPosition, Position, VerticalPosition};
 
 #[cfg(feature = "gecko")]