Add shorthand parsing/serialization for grid-template

3 files changed, 164 insertions, 2 deletions

diff --git a/components/style/properties/longhand/position.mako.rs b/components/style/properties/longhand/position.mako.rs
index 3f7011c4de5..754fc94732b 100644
--- a/components/style/properties/longhand/position.mako.rs
+++ b/components/style/properties/longhand/position.mako.rs
@@ -397,6 +397,13 @@ ${helpers.predefined_type("object-position",
             while let Ok(string) = input.try(Parser::expect_string) {
                 strings.push(string.into_owned().into_boxed_str());
             }
+
+            TemplateAreas::from_vec(strings)
+        }
+    }
+
+    impl TemplateAreas {
+        pub fn from_vec(strings: Vec<Box<str>>) -> Result<TemplateAreas, ()> {
             if strings.is_empty() {
                 return Err(());
             }
diff --git a/components/style/properties/shorthand/position.mako.rs b/components/style/properties/shorthand/position.mako.rs
index 11b2cd41b0b..1573a6a43e0 100644
--- a/components/style/properties/shorthand/position.mako.rs
+++ b/components/style/properties/shorthand/position.mako.rs
@@ -241,6 +241,159 @@
     }
 </%helpers:shorthand>
 
+<%helpers:shorthand name="grid-template"
+                    sub_properties="grid-template-rows grid-template-columns grid-template-areas"
+                    spec="https://drafts.csswg.org/css-grid/#propdef-grid-template"
+                    disable_when_testing="True"
+                    products="gecko">
+    use cssparser::serialize_string;
+    use parser::Parse;
+    use properties::longhands::grid_template_rows;
+    use properties::longhands::grid_template_areas::TemplateAreas;
+    use values::{Either, None_};
+    use values::generics::grid::{TrackSize, TrackList, TrackListType, concat_serialize_idents};
+    use values::specified::TrackListOrNone;
+    use values::specified::grid::parse_line_names;
+
+    /// Parsing for `<grid-template>` shorthand (also used by `grid` shorthand).
+    pub fn parse_grid_template(context: &ParserContext, input: &mut Parser)
+                               -> Result<(TrackListOrNone, TrackListOrNone, Either<TemplateAreas, None_>), ()> {
+        if input.try(|i| i.expect_ident_matching("none")).is_ok() {
+            return Ok((Either::Second(None_), Either::Second(None_), Either::Second(None_)))
+        }
+
+        let first_line_names = input.try(parse_line_names).unwrap_or(vec![]);
+        if let Ok(s) = input.try(Parser::expect_string) {
+            let mut strings = vec![];
+            let mut values = vec![];
+            let mut line_names = vec![];
+            let mut names = first_line_names;
+            let mut string = s.into_owned().into_boxed_str();
+            loop {
+                line_names.push(names);
+                strings.push(string);
+                let size = input.try(|i| TrackSize::parse(context, i)).unwrap_or_default();
+                values.push(Either::First(size));
+                names = input.try(parse_line_names).unwrap_or(vec![]);
+                if let Ok(v) = input.try(parse_line_names) {
+                    names.extend(v);
+                }
+
+                string = match input.try(Parser::expect_string) {
+                    Ok(s) => s.into_owned().into_boxed_str(),
+                    _ => {      // only the named area determines whether we should bail out
+                        line_names.push(names);
+                        break
+                    },
+                };
+            }
+
+            if line_names.len() == values.len() {
+                line_names.push(vec![]);        // should be one longer than track sizes
+            }
+
+            let template_areas = TemplateAreas::from_vec(strings)?;
+            let template_rows = TrackList {
+                list_type: TrackListType::Normal,
+                values: values,
+                line_names: line_names,
+                auto_repeat: None,
+            };
+
+            let template_cols = if input.try(|i| i.expect_delim('/')).is_ok() {
+                let track_list = TrackList::parse(context, input)?;
+                if track_list.list_type != TrackListType::Explicit {
+                    return Err(())
+                }
+
+                Either::First(track_list)
+            } else {
+                Either::Second(None_)
+            };
+
+            Ok((Either::First(template_rows), template_cols, Either::First(template_areas)))
+        } else {
+            let mut template_rows = grid_template_rows::parse(context, input)?;
+            if let Either::First(ref mut list) = template_rows {
+                list.line_names[0] = first_line_names;      // won't panic
+            }
+
+            Ok((template_rows, grid_template_rows::parse(context, input)?, Either::Second(None_)))
+        }
+    }
+
+    #[inline]
+    pub fn parse_value(context: &ParserContext, input: &mut Parser) -> Result<Longhands, ()> {
+        let (rows, columns, areas) = parse_grid_template(context, input)?;
+        Ok(expanded! {
+            grid_template_rows: rows,
+            grid_template_columns: columns,
+            grid_template_areas: areas,
+        })
+    }
+
+    /// Serialization for `<grid-template>` shorthand (also used by `grid` shorthand).
+    pub fn serialize_grid_template<W>(template_rows: &TrackListOrNone,
+                                      template_columns: &TrackListOrNone,
+                                      template_areas: &Either<TemplateAreas, None_>,
+                                      dest: &mut W) -> fmt::Result where W: fmt::Write {
+        match *template_areas {
+            Either::Second(_none) => {
+                if template_rows == &Either::Second(None_) &&
+                   template_columns == &Either::Second(None_) {
+                    dest.write_str("none")
+                } else {
+                    template_rows.to_css(dest)?;
+                    dest.write_str(" / ")?;
+                    template_columns.to_css(dest)
+                }
+            },
+            Either::First(ref areas) => {
+                let track_list = match *template_rows {
+                    Either::First(ref list) => list,
+                    Either::Second(_none) => unreachable!(),    // should exist!
+                };
+
+                let mut names_iter = track_list.line_names.iter();
+                for (((i, string), names), size) in areas.strings.iter().enumerate()
+                                                                 .zip(&mut names_iter)
+                                                                 .zip(track_list.values.iter()) {
+                    if i > 0 {
+                        dest.write_str(" ")?;
+                    }
+
+                    if !names.is_empty() {
+                        concat_serialize_idents("[", "] ", names, " ", dest)?;
+                    }
+
+                    serialize_string(string, dest)?;
+                    dest.write_str(" ")?;
+                    size.to_css(dest)?;
+                }
+
+                if let Some(names) = names_iter.next() {
+                    concat_serialize_idents(" [", "]", names, " ", dest)?;
+                }
+
+                if let Either::First(ref list) = *template_columns {
+                    dest.write_str(" / ")?;
+                    list.to_css(dest)?;
+                }
+
+                Ok(())
+            },
+        }
+    }
+
+    impl<'a> ToCss for LonghandsToSerialize<'a> {
+        #[inline]
+        fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+            serialize_grid_template(self.grid_template_rows, self.grid_template_columns,
+                                    self.grid_template_areas, dest)
+        }
+    }
+</%helpers:shorthand>
+
 <%helpers:shorthand name="place-content" sub_properties="align-content justify-content"
                     spec="https://drafts.csswg.org/css-align/#propdef-place-content"
                     products="gecko" disable_when_testing="True">
diff --git a/components/style/values/generics/grid.rs b/components/style/values/generics/grid.rs
index b2279c6b3f7..73640a91e49 100644
--- a/components/style/values/generics/grid.rs
+++ b/components/style/values/generics/grid.rs
@@ -306,8 +306,10 @@ impl<L: ToComputedValue> ToComputedValue for TrackSize<L> {
     }
 }
 
-fn concat_serialize_idents<W>(prefix: &str, suffix: &str,
-                              slice: &[String], sep: &str, dest: &mut W) -> fmt::Result
+/// Helper function for serializing identifiers with a prefix and suffix, used
+/// for serializing <line-names> (in grid).
+pub fn concat_serialize_idents<W>(prefix: &str, suffix: &str,
+                                  slice: &[String], sep: &str, dest: &mut W) -> fmt::Result
     where W: fmt::Write
 {
     if let Some((ref first, rest)) = slice.split_first() {