Add shorthand parsing and serialization for grid

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

@@ -394,6 +394,109 @@
     }
 </%helpers:shorthand>
 
+<%helpers:shorthand name="grid"
+                    sub_properties="grid-template-rows grid-template-columns grid-template-areas
+                                    grid-auto-rows grid-auto-columns grid-row-gap grid-column-gap
+                                    grid-auto-flow"
+                    spec="https://drafts.csswg.org/css-grid/#propdef-grid"
+                    disable_when_testing="True"
+                    products="gecko">
+    use properties::longhands::{grid_auto_columns, grid_auto_rows, grid_auto_flow};
+    use properties::longhands::{grid_template_columns, grid_template_rows};
+    use properties::longhands::grid_auto_flow::computed_value::{AutoFlow, T as SpecifiedAutoFlow};
+    use values::{Either, None_};
+    use values::specified::{LengthOrPercentage, TrackSize};
+
+    pub fn parse_value(context: &ParserContext, input: &mut Parser) -> Result<Longhands, ()> {
+        let mut temp_rows = Either::Second(None_);
+        let mut temp_cols = Either::Second(None_);
+        let mut temp_areas = Either::Second(None_);
+        let mut auto_rows = TrackSize::default();
+        let mut auto_cols = TrackSize::default();
+        let mut flow = grid_auto_flow::get_initial_value();
+
+        fn parse_auto_flow(input: &mut Parser, is_row: bool) -> Result<SpecifiedAutoFlow, ()> {
+            let mut auto_flow = None;
+            let mut dense = false;
+            for _ in 0..2 {
+                if input.try(|i| i.expect_ident_matching("auto-flow")).is_ok() {
+                    auto_flow = if is_row {
+                        Some(AutoFlow::Row)
+                    } else {
+                        Some(AutoFlow::Column)
+                    };
+                } else if input.try(|i| i.expect_ident_matching("dense")).is_ok() {
+                    dense = true;
+                } else {
+                    break
+                }
+            }
+
+            auto_flow.map(|flow| {
+                SpecifiedAutoFlow {
+                    autoflow: flow,
+                    dense: dense,
+                }
+            }).ok_or(())
+        }
+
+        if let Ok((rows, cols, areas)) = input.try(|i| super::grid_template::parse_grid_template(context, i)) {
+            temp_rows = rows;
+            temp_cols = cols;
+            temp_areas = areas;
+        } else if let Ok(rows) = input.try(|i| grid_template_rows::parse(context, i)) {
+            temp_rows = rows;
+            input.expect_delim('/')?;
+            flow = parse_auto_flow(input, false)?;
+            auto_cols = grid_auto_columns::parse(context, input).unwrap_or_default();
+        } else {
+            flow = parse_auto_flow(input, true)?;
+            auto_rows = input.try(|i| grid_auto_rows::parse(context, i)).unwrap_or_default();
+            input.expect_delim('/')?;
+            temp_cols = grid_template_columns::parse(context, input)?;
+        }
+
+        Ok(expanded! {
+            grid_template_rows: temp_rows,
+            grid_template_columns: temp_cols,
+            grid_template_areas: temp_areas,
+            grid_auto_rows: auto_rows,
+            grid_auto_columns: auto_cols,
+            grid_auto_flow: flow,
+            // This shorthand also resets grid gap
+            grid_row_gap: LengthOrPercentage::zero(),
+            grid_column_gap: LengthOrPercentage::zero(),
+        })
+    }
+
+    impl<'a> ToCss for LonghandsToSerialize<'a> {
+        fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+            if let Either::First(_) = *self.grid_template_areas {
+                super::grid_template::serialize_grid_template(self.grid_template_rows,
+                                                              self.grid_template_columns,
+                                                              self.grid_template_areas, dest)
+            } else if self.grid_auto_flow.autoflow == AutoFlow::Row {
+                self.grid_template_rows.to_css(dest)?;
+                dest.write_str(" / auto-flow")?;
+                if self.grid_auto_flow.dense {
+                    dest.write_str(" dense")?;
+                }
+
+                self.grid_auto_columns.to_css(dest)
+            } else {
+                dest.write_str("auto-flow ")?;
+                if self.grid_auto_flow.dense {
+                    dest.write_str("dense ")?;
+                }
+
+                self.grid_auto_rows.to_css(dest)?;
+                dest.write_str(" / ")?;
+                self.grid_template_columns.to_css(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">