Implement column-rule shorthand for stylo

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

@@ -273,6 +273,11 @@ ${helpers.single_keyword("column-fill", "auto balance",
         Au::from_px(3) // medium
     }
 
+    #[inline]
+    pub fn get_initial_specified_value() -> SpecifiedValue {
+        BorderWidth::Medium
+    }
+
     pub fn parse(context: &ParserContext, input: &mut Parser) -> Result<SpecifiedValue, ()> {
         BorderWidth::parse(context, input)
     }
@@ -289,8 +294,9 @@ ${helpers.predefined_type("-moz-column-rule-color", "CSSColor",
 ${helpers.single_keyword("column-span", "none all",
                          products="none", animatable=False)}
 
-${helpers.single_keyword("column-rule-style",
+${helpers.single_keyword("-moz-column-rule-style",
                          "none hidden dotted dashed solid double groove ridge inset outset",
                          products="gecko",
+                         gecko_ffi_name="mColumnRuleStyle",
                          gecko_constant_prefix="NS_STYLE_BORDER_STYLE",
                          animatable=False)}

components/style/properties/shorthand/column.mako.rs

@@ -57,3 +57,71 @@
         }
     }
 </%helpers:shorthand>
+
+// https://drafts.csswg.org/css-multicol/#column-rule
+<%helpers:shorthand name="-moz-column-rule" products="gecko"
+    sub_properties="-moz-column-rule-width -moz-column-rule-style -moz-column-rule-color">
+    use properties::longhands::{_moz_column_rule_width, _moz_column_rule_style};
+    use properties::longhands::_moz_column_rule_color;
+
+    pub fn parse_value(context: &ParserContext, input: &mut Parser) -> Result<Longhands, ()> {
+        % for name in "width style color".split():
+        let mut column_rule_${name} = None;
+        % endfor
+        let mut any = false;
+
+        loop {
+            % for name in "width style color".split():
+            if column_rule_${name}.is_none() {
+                if let Ok(value) = input.try(|input|
+                        _moz_column_rule_${name}::parse(context, input)) {
+                    column_rule_${name} = Some(value);
+                    any = true;
+                    continue
+                }
+            }
+            % endfor
+
+            break
+        }
+        if any {
+            Ok(Longhands {
+                % for name in "width style".split():
+                    _moz_column_rule_${name}: column_rule_${name}
+                        .or(Some(_moz_column_rule_${name}::get_initial_specified_value())),
+                % endfor
+                _moz_column_rule_color: column_rule_color,
+            })
+        } else {
+            Err(())
+        }
+    }
+
+    impl<'a> LonghandsToSerialize<'a>  {
+        fn to_css_declared<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+            let mut need_space = false;
+            try!(self._moz_column_rule_width.to_css(dest));
+
+            if let DeclaredValue::Value(ref width) = *self._moz_column_rule_width {
+                try!(width.to_css(dest));
+                need_space = true;
+            }
+
+            if let DeclaredValue::Value(ref style) = *self._moz_column_rule_style {
+                if need_space {
+                    try!(write!(dest, " "));
+                }
+                try!(style.to_css(dest));
+                need_space = true;
+            }
+
+            if let DeclaredValue::Value(ref color) = *self._moz_column_rule_color {
+                if need_space {
+                    try!(write!(dest, " "));
+                }
+                try!(color.to_css(dest));
+            }
+            Ok(())
+        }
+    }
+</%helpers:shorthand>