style: Add support for 'flex-basis:content' in the style system.

Bug: 1105111
Reviewed-by: xidorn
MozReview-Commit-ID: 5WhgHJJ0mDB

components/style/values/specified/flex.rs

@@ -8,22 +8,42 @@ use cssparser::Parser;
 use parser::{Parse, ParserContext};
 use style_traits::ParseError;
 use values::generics::flex::FlexBasis as GenericFlexBasis;
-use values::specified::length::LengthOrPercentage;
+
+/// The `width` value type.
+#[cfg(feature = "servo")]
+pub type Width = ::values::specified::NonNegativeLengthOrPercentageOrAuto;
+
+/// The `width` value type.
+#[cfg(feature = "gecko")]
+pub type Width = ::values::specified::MozLength;
 
 /// A specified value for the `flex-basis` property.
-pub type FlexBasis = GenericFlexBasis<LengthOrPercentage>;
+pub type FlexBasis = GenericFlexBasis<Width>;
 
 impl Parse for FlexBasis {
     fn parse<'i, 't>(
         context: &ParserContext,
-        input: &mut Parser<'i, 't>)
-    -> Result<Self, ParseError<'i>> {
-        if let Ok(length) = input.try(|i| LengthOrPercentage::parse_non_negative(context, i)) {
-            return Ok(GenericFlexBasis::Length(length));
+        input: &mut Parser<'i, 't>,
+    ) -> Result<Self, ParseError<'i>> {
+        if let Ok(width) = input.try(|i| Width::parse(context, i)) {
+            return Ok(GenericFlexBasis::Width(width));
         }
         try_match_ident_ignore_ascii_case! { input,
-            "auto" => Ok(GenericFlexBasis::Auto),
             "content" => Ok(GenericFlexBasis::Content),
         }
     }
 }
+
+impl FlexBasis {
+    /// `auto`
+    #[inline]
+    pub fn auto() -> Self {
+        GenericFlexBasis::Width(Width::auto())
+    }
+
+    /// `0%`
+    #[inline]
+    pub fn zero_percent() -> Self {
+        GenericFlexBasis::Width(Width::zero_percent())
+    }
+}

components/style/values/specified/length.rs

@@ -914,6 +914,16 @@ impl LengthOrPercentageOrAuto {
     pub fn zero_percent() -> Self {
         LengthOrPercentageOrAuto::Percentage(computed::Percentage::zero())
     }
+
+    /// Parses, with quirks.
+    #[inline]
+    pub fn parse_quirky<'i, 't>(
+        context: &ParserContext,
+        input: &mut Parser<'i, 't>,
+        allow_quirks: AllowQuirks,
+    ) -> Result<Self, ParseError<'i>> {
+        Self::parse_internal(context, input, AllowedNumericType::All, allow_quirks)
+    }
 }
 
 impl Parse for LengthOrPercentageOrAuto {
@@ -923,14 +933,33 @@ impl Parse for LengthOrPercentageOrAuto {
     }
 }
 
-impl LengthOrPercentageOrAuto {
-    /// Parses, with quirks.
+/// A wrapper of LengthOrPercentageOrAuto, whose value must be >= 0.
+pub type NonNegativeLengthOrPercentageOrAuto = NonNegative<LengthOrPercentageOrAuto>;
+
+impl NonNegativeLengthOrPercentageOrAuto {
+    /// 0
     #[inline]
-    pub fn parse_quirky<'i, 't>(context: &ParserContext,
-                                input: &mut Parser<'i, 't>,
-                                allow_quirks: AllowQuirks)
-                                -> Result<Self, ParseError<'i>> {
-        Self::parse_internal(context, input, AllowedNumericType::All, allow_quirks)
+    pub fn zero() -> Self {
+        NonNegative(LengthOrPercentageOrAuto::zero())
+    }
+
+    /// 0%
+    #[inline]
+    pub fn zero_percent() -> Self {
+        NonNegative(LengthOrPercentageOrAuto::zero_percent())
+    }
+
+    /// `auto`
+    #[inline]
+    pub fn auto() -> Self {
+        NonNegative(LengthOrPercentageOrAuto::Auto)
+    }
+}
+
+impl Parse for NonNegativeLengthOrPercentageOrAuto {
+    #[inline]
+    fn parse<'i, 't>(context: &ParserContext, input: &mut Parser<'i, 't>) -> Result<Self, ParseError<'i>> {
+        Ok(NonNegative(LengthOrPercentageOrAuto::parse_non_negative(context, input)?))
     }
 }
 
@@ -1090,8 +1119,11 @@ impl LengthOrNumber {
 }
 
 /// A value suitable for a `min-width` or `min-height` property.
-/// Unlike `max-width` or `max-height` properties, a MozLength can be
-/// `auto`, and cannot be `none`.
+///
+/// Unlike `max-width` or `max-height` properties, a MozLength can be `auto`,
+/// and cannot be `none`.
+///
+/// Note that it only accepts non-negative values.
 #[allow(missing_docs)]
 #[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
 pub enum MozLength {

components/style/values/specified/mod.rs

@@ -55,7 +55,7 @@ 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};
-pub use self::length::NonNegativeLengthOrPercentage;
+pub use self::length::{NonNegativeLengthOrPercentage, NonNegativeLengthOrPercentageOrAuto};
 pub use self::list::{ListStyleImage, Quotes};
 #[cfg(feature = "gecko")]
 pub use self::list::ListStyleType;