Adding upstream version 1:115.7.0.upstream/1%115.7.0upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 879 insertions, 0 deletions

diff --git a/servo/components/style/properties/shorthands/position.mako.rs b/servo/components/style/properties/shorthands/position.mako.rs
new file mode 100644
index 0000000000..3413a9038b
--- /dev/null
+++ b/servo/components/style/properties/shorthands/position.mako.rs
@@ -0,0 +1,879 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+<%namespace name="helpers" file="/helpers.mako.rs" />
+
+<%helpers:shorthand name="flex-flow"
+                    engines="gecko servo-2013 servo-2020",
+                    servo_2020_pref="layout.flexbox.enabled",
+                    sub_properties="flex-direction flex-wrap"
+                    extra_prefixes="webkit"
+                    derive_serialize="True"
+                    spec="https://drafts.csswg.org/css-flexbox/#flex-flow-property">
+    use crate::properties::longhands::{flex_direction, flex_wrap};
+
+    pub fn parse_value<'i, 't>(
+        context: &ParserContext,
+        input: &mut Parser<'i, 't>,
+    ) -> Result<Longhands, ParseError<'i>> {
+        let mut direction = None;
+        let mut wrap = None;
+        loop {
+            if direction.is_none() {
+                if let Ok(value) = input.try_parse(|input| flex_direction::parse(context, input)) {
+                    direction = Some(value);
+                    continue
+                }
+            }
+            if wrap.is_none() {
+                if let Ok(value) = input.try_parse(|input| flex_wrap::parse(context, input)) {
+                    wrap = Some(value);
+                    continue
+                }
+            }
+            break
+        }
+
+        if direction.is_none() && wrap.is_none() {
+            return Err(input.new_custom_error(StyleParseErrorKind::UnspecifiedError))
+        }
+        Ok(expanded! {
+            flex_direction: unwrap_or_initial!(flex_direction, direction),
+            flex_wrap: unwrap_or_initial!(flex_wrap, wrap),
+        })
+    }
+</%helpers:shorthand>
+
+<%helpers:shorthand name="flex"
+                    engines="gecko servo-2013 servo-2020",
+                    servo_2020_pref="layout.flexbox.enabled",
+                    sub_properties="flex-grow flex-shrink flex-basis"
+                    extra_prefixes="webkit"
+                    derive_serialize="True"
+                    spec="https://drafts.csswg.org/css-flexbox/#flex-property">
+    use crate::parser::Parse;
+    use crate::values::specified::NonNegativeNumber;
+    use crate::properties::longhands::flex_basis::SpecifiedValue as FlexBasis;
+
+    fn parse_flexibility<'i, 't>(
+        context: &ParserContext,
+        input: &mut Parser<'i, 't>,
+    ) -> Result<(NonNegativeNumber, Option<NonNegativeNumber>),ParseError<'i>> {
+        let grow = NonNegativeNumber::parse(context, input)?;
+        let shrink = input.try_parse(|i| NonNegativeNumber::parse(context, i)).ok();
+        Ok((grow, shrink))
+    }
+
+    pub fn parse_value<'i, 't>(
+        context: &ParserContext,
+        input: &mut Parser<'i, 't>,
+    ) -> Result<Longhands, ParseError<'i>> {
+        let mut grow = None;
+        let mut shrink = None;
+        let mut basis = None;
+
+        if input.try_parse(|input| input.expect_ident_matching("none")).is_ok() {
+            return Ok(expanded! {
+                flex_grow: NonNegativeNumber::new(0.0),
+                flex_shrink: NonNegativeNumber::new(0.0),
+                flex_basis: FlexBasis::auto(),
+            })
+        }
+        loop {
+            if grow.is_none() {
+                if let Ok((flex_grow, flex_shrink)) = input.try_parse(|i| parse_flexibility(context, i)) {
+                    grow = Some(flex_grow);
+                    shrink = flex_shrink;
+                    continue
+                }
+            }
+            if basis.is_none() {
+                if let Ok(value) = input.try_parse(|input| FlexBasis::parse(context, input)) {
+                    basis = Some(value);
+                    continue
+                }
+            }
+            break
+        }
+
+        if grow.is_none() && basis.is_none() {
+            return Err(input.new_custom_error(StyleParseErrorKind::UnspecifiedError))
+        }
+        Ok(expanded! {
+            flex_grow: grow.unwrap_or(NonNegativeNumber::new(1.0)),
+            flex_shrink: shrink.unwrap_or(NonNegativeNumber::new(1.0)),
+            // Per spec, this should be SpecifiedValue::zero(), but all
+            // browsers currently agree on using `0%`. This is a spec
+            // change which hasn't been adopted by browsers:
+            // https://github.com/w3c/csswg-drafts/commit/2c446befdf0f686217905bdd7c92409f6bd3921b
+            flex_basis: basis.unwrap_or(FlexBasis::zero_percent()),
+        })
+    }
+</%helpers:shorthand>
+
+<%helpers:shorthand
+    name="gap"
+    engines="gecko"
+    aliases="grid-gap"
+    sub_properties="row-gap column-gap"
+    spec="https://drafts.csswg.org/css-align-3/#gap-shorthand"
+>
+  use crate::properties::longhands::{row_gap, column_gap};
+
+  pub fn parse_value<'i, 't>(context: &ParserContext, input: &mut Parser<'i, 't>)
+                             -> Result<Longhands, ParseError<'i>> {
+      let r_gap = row_gap::parse(context, input)?;
+      let c_gap = input.try_parse(|input| column_gap::parse(context, input)).unwrap_or(r_gap.clone());
+
+      Ok(expanded! {
+        row_gap: r_gap,
+        column_gap: c_gap,
+      })
+  }
+
+  impl<'a> ToCss for LonghandsToSerialize<'a>  {
+      fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result where W: fmt::Write {
+          if self.row_gap == self.column_gap {
+            self.row_gap.to_css(dest)
+          } else {
+            self.row_gap.to_css(dest)?;
+            dest.write_char(' ')?;
+            self.column_gap.to_css(dest)
+          }
+      }
+  }
+
+</%helpers:shorthand>
+
+% for kind in ["row", "column"]:
+<%helpers:shorthand
+    name="grid-${kind}"
+    sub_properties="grid-${kind}-start grid-${kind}-end"
+    engines="gecko",
+    spec="https://drafts.csswg.org/css-grid/#propdef-grid-${kind}"
+>
+    use crate::values::specified::GridLine;
+    use crate::parser::Parse;
+    use crate::Zero;
+
+    // NOTE: Since both the shorthands have the same code, we should (re-)use code from one to implement
+    // the other. This might not be a big deal for now, but we should consider looking into this in the future
+    // to limit the amount of code generated.
+    pub fn parse_value<'i, 't>(
+        context: &ParserContext,
+        input: &mut Parser<'i, 't>,
+    ) -> Result<Longhands, ParseError<'i>> {
+        let start = input.try_parse(|i| GridLine::parse(context, i))?;
+        let end = if input.try_parse(|i| i.expect_delim('/')).is_ok() {
+            GridLine::parse(context, input)?
+        } else {
+            let mut line = GridLine::auto();
+            if start.line_num.is_zero() && !start.is_span {
+                line.ident = start.ident.clone(); // ident from start value should be taken
+            }
+
+            line
+        };
+
+        Ok(expanded! {
+            grid_${kind}_start: start,
+            grid_${kind}_end: end,
+        })
+    }
+
+    impl<'a> ToCss for LonghandsToSerialize<'a> {
+        // Return the shortest possible serialization of the `grid-${kind}-[start/end]` values.
+        // This function exploits the opportunities to omit the end value per this spec text:
+        //
+        // https://drafts.csswg.org/css-grid/#propdef-grid-column
+        // "When the second value is omitted, if the first value is a <custom-ident>,
+        // the grid-row-end/grid-column-end longhand is also set to that <custom-ident>;
+        // otherwise, it is set to auto."
+        fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result where W: fmt::Write {
+            self.grid_${kind}_start.to_css(dest)?;
+            if self.grid_${kind}_start.can_omit(self.grid_${kind}_end) {
+                return Ok(());  // the end value is redundant
+            }
+            dest.write_str(" / ")?;
+            self.grid_${kind}_end.to_css(dest)
+        }
+    }
+</%helpers:shorthand>
+% endfor
+
+<%helpers:shorthand
+    name="grid-area"
+    engines="gecko"
+    sub_properties="grid-row-start grid-row-end grid-column-start grid-column-end"
+    spec="https://drafts.csswg.org/css-grid/#propdef-grid-area"
+>
+    use crate::values::specified::GridLine;
+    use crate::parser::Parse;
+    use crate::Zero;
+
+    // The code is the same as `grid-{row,column}` except that this can have four values at most.
+    pub fn parse_value<'i, 't>(
+        context: &ParserContext,
+        input: &mut Parser<'i, 't>,
+    ) -> Result<Longhands, ParseError<'i>> {
+        fn line_with_ident_from(other: &GridLine) -> GridLine {
+            let mut this = GridLine::auto();
+            if other.line_num.is_zero() && !other.is_span {
+                this.ident = other.ident.clone();
+            }
+
+            this
+        }
+
+        let row_start = input.try_parse(|i| GridLine::parse(context, i))?;
+        let (column_start, row_end, column_end) = if input.try_parse(|i| i.expect_delim('/')).is_ok() {
+            let column_start = GridLine::parse(context, input)?;
+            let (row_end, column_end) = if input.try_parse(|i| i.expect_delim('/')).is_ok() {
+                let row_end = GridLine::parse(context, input)?;
+                let column_end = if input.try_parse(|i| i.expect_delim('/')).is_ok() {
+                    GridLine::parse(context, input)?
+                } else {        // grid-column-end has not been given
+                    line_with_ident_from(&column_start)
+                };
+
+                (row_end, column_end)
+            } else {        // grid-row-start and grid-column-start has been given
+                let row_end = line_with_ident_from(&row_start);
+                let column_end = line_with_ident_from(&column_start);
+                (row_end, column_end)
+            };
+
+            (column_start, row_end, column_end)
+        } else {        // only grid-row-start is given
+            let line = line_with_ident_from(&row_start);
+            (line.clone(), line.clone(), line)
+        };
+
+        Ok(expanded! {
+            grid_row_start: row_start,
+            grid_row_end: row_end,
+            grid_column_start: column_start,
+            grid_column_end: column_end,
+        })
+    }
+
+    impl<'a> ToCss for LonghandsToSerialize<'a> {
+        // Return the shortest possible serialization of the `grid-[column/row]-[start/end]` values.
+        // This function exploits the opportunities to omit trailing values per this spec text:
+        //
+        // https://drafts.csswg.org/css-grid/#propdef-grid-area
+        // "If four <grid-line> values are specified, grid-row-start is set to the first value,
+        // grid-column-start is set to the second value, grid-row-end is set to the third value,
+        // and grid-column-end is set to the fourth value.
+        //
+        // When grid-column-end is omitted, if grid-column-start is a <custom-ident>,
+        // grid-column-end is set to that <custom-ident>; otherwise, it is set to auto.
+        //
+        // When grid-row-end is omitted, if grid-row-start is a <custom-ident>, grid-row-end is
+        // set to that <custom-ident>; otherwise, it is set to auto.
+        //
+        // When grid-column-start is omitted, if grid-row-start is a <custom-ident>, all four
+        // longhands are set to that value. Otherwise, it is set to auto."
+        fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result where W: fmt::Write {
+            self.grid_row_start.to_css(dest)?;
+            let mut trailing_values = 3;
+            if self.grid_column_start.can_omit(self.grid_column_end) {
+                trailing_values -= 1;
+                if self.grid_row_start.can_omit(self.grid_row_end) {
+                    trailing_values -= 1;
+                    if self.grid_row_start.can_omit(self.grid_column_start) {
+                        trailing_values -= 1;
+                    }
+                }
+            }
+            let values = [&self.grid_column_start, &self.grid_row_end, &self.grid_column_end];
+            for value in values.iter().take(trailing_values) {
+                dest.write_str(" / ")?;
+                value.to_css(dest)?;
+            }
+            Ok(())
+        }
+    }
+</%helpers:shorthand>
+
+<%helpers:shorthand
+    name="grid-template"
+    engines="gecko"
+    sub_properties="grid-template-rows grid-template-columns grid-template-areas"
+    spec="https://drafts.csswg.org/css-grid/#propdef-grid-template"
+>
+    use crate::parser::Parse;
+    use servo_arc::Arc;
+    use crate::values::generics::grid::{TrackSize, TrackList};
+    use crate::values::generics::grid::{TrackListValue, concat_serialize_idents};
+    use crate::values::specified::{GridTemplateComponent, GenericGridTemplateComponent};
+    use crate::values::specified::grid::parse_line_names;
+    use crate::values::specified::position::{GridTemplateAreas, TemplateAreas, TemplateAreasArc};
+
+    /// Parsing for `<grid-template>` shorthand (also used by `grid` shorthand).
+    pub fn parse_grid_template<'i, 't>(
+        context: &ParserContext,
+        input: &mut Parser<'i, 't>,
+    ) -> Result<(GridTemplateComponent, GridTemplateComponent, GridTemplateAreas), ParseError<'i>> {
+        // Other shorthand sub properties also parse the `none` keyword and this shorthand
+        // should know after this keyword there is nothing to parse. Otherwise it gets
+        // confused and rejects the sub properties that contains `none`.
+        <% keywords = {
+            "none": "GenericGridTemplateComponent::None",
+        }
+        %>
+        % for keyword, rust_type in keywords.items():
+            if let Ok(x) = input.try_parse(|i| {
+                if i.try_parse(|i| i.expect_ident_matching("${keyword}")).is_ok() {
+                    if !i.is_exhausted() {
+                        return Err(());
+                    }
+                    return Ok((${rust_type}, ${rust_type}, GridTemplateAreas::None));
+                }
+                Err(())
+            }) {
+                return Ok(x);
+            }
+        % endfor
+
+        let first_line_names = input.try_parse(parse_line_names).unwrap_or_default();
+        if let Ok(string) = input.try_parse(|i| i.expect_string().map(|s| s.as_ref().to_owned().into())) {
+            let mut strings = vec![];
+            let mut values = vec![];
+            let mut line_names = vec![];
+            line_names.push(first_line_names);
+            strings.push(string);
+            loop {
+                let size = input.try_parse(|i| TrackSize::parse(context, i)).unwrap_or_default();
+                values.push(TrackListValue::TrackSize(size));
+                let mut names = input.try_parse(parse_line_names).unwrap_or_default();
+                let more_names = input.try_parse(parse_line_names);
+
+                match input.try_parse(|i| i.expect_string().map(|s| s.as_ref().to_owned().into())) {
+                    Ok(string) => {
+                        strings.push(string);
+                        if let Ok(v) = more_names {
+                            // We got `[names] [more_names] "string"` - merge the two name lists.
+                            let mut names_vec = names.into_vec();
+                            names_vec.extend(v.into_iter());
+                            names = names_vec.into();
+                        }
+                        line_names.push(names);
+                    },
+                    Err(e) => {
+                        if more_names.is_ok() {
+                            // We've parsed `"string" [names] [more_names]` but then failed to parse another `"string"`.
+                            // The grammar doesn't allow two trailing `<line-names>` so this is an invalid value.
+                            return Err(e.into());
+                        }
+                        // only the named area determines whether we should bail out
+                        line_names.push(names);
+                        break
+                    },
+                };
+            }
+
+            if line_names.len() == values.len() {
+                // should be one longer than track sizes
+                line_names.push(Default::default());
+            }
+
+            let template_areas = TemplateAreas::from_vec(strings)
+                .map_err(|()| input.new_custom_error(StyleParseErrorKind::UnspecifiedError))?;
+            let template_rows = TrackList {
+                values: values.into(),
+                line_names: line_names.into(),
+                auto_repeat_index: std::usize::MAX,
+            };
+
+            let template_cols = if input.try_parse(|i| i.expect_delim('/')).is_ok() {
+                let value = GridTemplateComponent::parse_without_none(context, input)?;
+                if let GenericGridTemplateComponent::TrackList(ref list) = value {
+                    if !list.is_explicit() {
+                        return Err(input.new_custom_error(StyleParseErrorKind::UnspecifiedError))
+                    }
+                }
+
+                value
+            } else {
+                GridTemplateComponent::default()
+            };
+
+            Ok((
+                GenericGridTemplateComponent::TrackList(Box::new(template_rows)),
+                template_cols,
+                GridTemplateAreas::Areas(TemplateAreasArc(Arc::new(template_areas)))
+            ))
+        } else {
+            let mut template_rows = GridTemplateComponent::parse(context, input)?;
+            if let GenericGridTemplateComponent::TrackList(ref mut list) = template_rows {
+                // Fist line names are parsed already and it shouldn't be parsed again.
+                // If line names are not empty, that means given property value is not acceptable
+                if list.line_names[0].is_empty() {
+                    list.line_names[0] = first_line_names;      // won't panic
+                } else {
+                    return Err(input.new_custom_error(StyleParseErrorKind::UnspecifiedError));
+                }
+            }
+
+            input.expect_delim('/')?;
+            Ok((template_rows, GridTemplateComponent::parse(context, input)?, GridTemplateAreas::None))
+        }
+    }
+
+    #[inline]
+    pub fn parse_value<'i, 't>(
+        context: &ParserContext,
+        input: &mut Parser<'i, 't>,
+    ) -> Result<Longhands, ParseError<'i>> {
+        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: &GridTemplateComponent,
+        template_columns: &GridTemplateComponent,
+        template_areas: &GridTemplateAreas,
+        dest: &mut CssWriter<W>,
+    ) -> fmt::Result
+    where
+        W: Write {
+        match *template_areas {
+            GridTemplateAreas::None => {
+                if template_rows.is_initial() && template_columns.is_initial() {
+                    return GridTemplateComponent::default().to_css(dest);
+                }
+                template_rows.to_css(dest)?;
+                dest.write_str(" / ")?;
+                template_columns.to_css(dest)
+            },
+            GridTemplateAreas::Areas(ref areas) => {
+                // The length of template-area and template-rows values should be equal.
+                if areas.0.strings.len() != template_rows.track_list_len() {
+                    return Ok(());
+                }
+
+                let track_list = match *template_rows {
+                    GenericGridTemplateComponent::TrackList(ref list) => {
+                        // We should fail if there is a `repeat` function.
+                        // `grid` and `grid-template` shorthands doesn't accept
+                        // that. Only longhand accepts.
+                        if !list.is_explicit() {
+                            return Ok(());
+                        }
+                        list
+                    },
+                    // Others template components shouldn't exist with normal shorthand values.
+                    // But if we need to serialize a group of longhand sub-properties for
+                    // the shorthand, we should be able to return empty string instead of crashing.
+                    _ => return Ok(()),
+                };
+
+                // We need to check some values that longhand accepts but shorthands don't.
+                match *template_columns {
+                    // We should fail if there is a `repeat` function. `grid` and
+                    // `grid-template` shorthands doesn't accept that. Only longhand accepts that.
+                    GenericGridTemplateComponent::TrackList(ref list) => {
+                        if !list.is_explicit() {
+                            return Ok(());
+                        }
+                    },
+                    // Also the shorthands don't accept subgrids unlike longhand.
+                    // We should fail without an error here.
+                    GenericGridTemplateComponent::Subgrid(_) => {
+                        return Ok(());
+                    },
+                    _ => {},
+                }
+
+                let mut names_iter = track_list.line_names.iter();
+                for (((i, string), names), value) in areas.0.strings.iter().enumerate()
+                                                                  .zip(&mut names_iter)
+                                                                  .zip(track_list.values.iter()) {
+                    if i > 0 {
+                        dest.write_char(' ')?;
+                    }
+
+                    if !names.is_empty() {
+                        concat_serialize_idents("[", "] ", names, " ", dest)?;
+                    }
+
+                    string.to_css(dest)?;
+
+                    // If the track size is the initial value then it's redundant here.
+                    if !value.is_initial() {
+                        dest.write_char(' ')?;
+                        value.to_css(dest)?;
+                    }
+                }
+
+                if let Some(names) = names_iter.next() {
+                    concat_serialize_idents(" [", "]", names, " ", dest)?;
+                }
+
+                if let GenericGridTemplateComponent::TrackList(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 CssWriter<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="grid"
+    engines="gecko"
+    sub_properties="grid-template-rows grid-template-columns grid-template-areas
+                    grid-auto-rows grid-auto-columns grid-auto-flow"
+    spec="https://drafts.csswg.org/css-grid/#propdef-grid"
+>
+    use crate::parser::Parse;
+    use crate::properties::longhands::{grid_auto_columns, grid_auto_rows, grid_auto_flow};
+    use crate::values::generics::grid::GridTemplateComponent;
+    use crate::values::specified::{GenericGridTemplateComponent, ImplicitGridTracks};
+    use crate::values::specified::position::{GridAutoFlow, GridTemplateAreas};
+
+    pub fn parse_value<'i, 't>(
+        context: &ParserContext,
+        input: &mut Parser<'i, 't>,
+    ) -> Result<Longhands, ParseError<'i>> {
+        let mut temp_rows = GridTemplateComponent::default();
+        let mut temp_cols = GridTemplateComponent::default();
+        let mut temp_areas = GridTemplateAreas::None;
+        let mut auto_rows = ImplicitGridTracks::default();
+        let mut auto_cols = ImplicitGridTracks::default();
+        let mut flow = grid_auto_flow::get_initial_value();
+
+        fn parse_auto_flow<'i, 't>(
+            input: &mut Parser<'i, 't>,
+            is_row: bool,
+        ) -> Result<GridAutoFlow, ParseError<'i>> {
+            let mut track = None;
+            let mut dense = GridAutoFlow::empty();
+
+            for _ in 0..2 {
+                if input.try_parse(|i| i.expect_ident_matching("auto-flow")).is_ok() {
+                    track = if is_row {
+                        Some(GridAutoFlow::ROW)
+                    } else {
+                        Some(GridAutoFlow::COLUMN)
+                    };
+                } else if input.try_parse(|i| i.expect_ident_matching("dense")).is_ok() {
+                    dense = GridAutoFlow::DENSE
+                } else {
+                    break
+                }
+            }
+
+            if track.is_some() {
+                Ok(track.unwrap() | dense)
+            } else {
+                Err(input.new_custom_error(StyleParseErrorKind::UnspecifiedError))
+            }
+        }
+
+        if let Ok((rows, cols, areas)) = input.try_parse(|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_parse(|i| GridTemplateComponent::parse(context, i)) {
+            temp_rows = rows;
+            input.expect_delim('/')?;
+            flow = parse_auto_flow(input, false)?;
+            auto_cols = input.try_parse(|i| grid_auto_columns::parse(context, i)).unwrap_or_default();
+        } else {
+            flow = parse_auto_flow(input, true)?;
+            auto_rows = input.try_parse(|i| grid_auto_rows::parse(context, i)).unwrap_or_default();
+            input.expect_delim('/')?;
+            temp_cols = GridTemplateComponent::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,
+        })
+    }
+
+    impl<'a> LonghandsToSerialize<'a> {
+        /// Returns true if other sub properties except template-{rows,columns} are initial.
+        fn is_grid_template(&self) -> bool {
+            self.grid_auto_rows.is_initial() &&
+            self.grid_auto_columns.is_initial() &&
+            *self.grid_auto_flow == grid_auto_flow::get_initial_value()
+        }
+    }
+
+    impl<'a> ToCss for LonghandsToSerialize<'a> {
+        fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result where W: fmt::Write {
+            if self.is_grid_template() {
+                return super::grid_template::serialize_grid_template(
+                    self.grid_template_rows,
+                    self.grid_template_columns,
+                    self.grid_template_areas,
+                    dest
+                );
+            }
+
+            if *self.grid_template_areas != GridTemplateAreas::None {
+                // No other syntax can set the template areas, so fail to
+                // serialize.
+                return Ok(());
+            }
+
+            if self.grid_auto_flow.contains(GridAutoFlow::COLUMN) {
+                // It should fail to serialize if other branch of the if condition's values are set.
+                if !self.grid_auto_rows.is_initial() ||
+                    !self.grid_template_columns.is_initial() {
+                    return Ok(());
+                }
+
+                // It should fail to serialize if template-rows value is not Explicit.
+                if let GenericGridTemplateComponent::TrackList(ref list) = *self.grid_template_rows {
+                    if !list.is_explicit() {
+                        return Ok(());
+                    }
+                }
+
+                self.grid_template_rows.to_css(dest)?;
+                dest.write_str(" / auto-flow")?;
+                if self.grid_auto_flow.contains(GridAutoFlow::DENSE) {
+                    dest.write_str(" dense")?;
+                }
+
+                if !self.grid_auto_columns.is_initial() {
+                    dest.write_char(' ')?;
+                    self.grid_auto_columns.to_css(dest)?;
+                }
+
+                return Ok(());
+            }
+
+            // It should fail to serialize if other branch of the if condition's values are set.
+            if !self.grid_auto_columns.is_initial() ||
+                !self.grid_template_rows.is_initial() {
+                return Ok(());
+            }
+
+            // It should fail to serialize if template-column value is not Explicit.
+            if let GenericGridTemplateComponent::TrackList(ref list) = *self.grid_template_columns {
+                if !list.is_explicit() {
+                    return Ok(());
+                }
+            }
+
+            dest.write_str("auto-flow")?;
+            if self.grid_auto_flow.contains(GridAutoFlow::DENSE) {
+                dest.write_str(" dense")?;
+            }
+
+            if !self.grid_auto_rows.is_initial() {
+                dest.write_char(' ')?;
+                self.grid_auto_rows.to_css(dest)?;
+            }
+
+            dest.write_str(" / ")?;
+            self.grid_template_columns.to_css(dest)?;
+            Ok(())
+        }
+    }
+</%helpers:shorthand>
+
+<%helpers:shorthand
+    name="place-content"
+    engines="gecko"
+    sub_properties="align-content justify-content"
+    spec="https://drafts.csswg.org/css-align/#propdef-place-content"
+>
+    use crate::values::specified::align::{AlignContent, JustifyContent, ContentDistribution, AxisDirection};
+
+    pub fn parse_value<'i, 't>(
+        _: &ParserContext,
+        input: &mut Parser<'i, 't>,
+    ) -> Result<Longhands, ParseError<'i>> {
+        let align_content =
+            ContentDistribution::parse(input, AxisDirection::Block)?;
+
+        let justify_content = input.try_parse(|input| {
+            ContentDistribution::parse(input, AxisDirection::Inline)
+        });
+
+        let justify_content = match justify_content {
+            Ok(v) => v,
+            Err(..) => {
+                // https://drafts.csswg.org/css-align-3/#place-content:
+                //
+                //   The second value is assigned to justify-content; if
+                //   omitted, it is copied from the first value, unless that
+                //   value is a <baseline-position> in which case it is
+                //   defaulted to start.
+                //
+                if !align_content.is_baseline_position() {
+                    align_content
+                } else {
+                    ContentDistribution::start()
+                }
+            }
+        };
+
+        Ok(expanded! {
+            align_content: AlignContent(align_content),
+            justify_content: JustifyContent(justify_content),
+        })
+    }
+
+    impl<'a> ToCss for LonghandsToSerialize<'a> {
+        fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result where W: fmt::Write {
+            self.align_content.to_css(dest)?;
+            if self.align_content.0 != self.justify_content.0 {
+                dest.write_char(' ')?;
+                self.justify_content.to_css(dest)?;
+            }
+            Ok(())
+        }
+    }
+</%helpers:shorthand>
+
+<%helpers:shorthand
+    name="place-self"
+    engines="gecko"
+    sub_properties="align-self justify-self"
+    spec="https://drafts.csswg.org/css-align/#place-self-property"
+>
+    use crate::values::specified::align::{AlignSelf, JustifySelf, SelfAlignment, AxisDirection};
+
+    pub fn parse_value<'i, 't>(
+        _: &ParserContext,
+        input: &mut Parser<'i, 't>,
+    ) -> Result<Longhands, ParseError<'i>> {
+        let align = SelfAlignment::parse(input, AxisDirection::Block)?;
+        let justify = input.try_parse(|input| SelfAlignment::parse(input, AxisDirection::Inline));
+
+        let justify = match justify {
+            Ok(v) => v,
+            Err(..) => {
+                debug_assert!(align.is_valid_on_both_axes());
+                align
+            }
+        };
+
+        Ok(expanded! {
+            align_self: AlignSelf(align),
+            justify_self: JustifySelf(justify),
+        })
+    }
+
+    impl<'a> ToCss for LonghandsToSerialize<'a> {
+        fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result where W: fmt::Write {
+            self.align_self.to_css(dest)?;
+            if self.align_self.0 != self.justify_self.0 {
+                dest.write_char(' ')?;
+                self.justify_self.to_css(dest)?;
+            }
+            Ok(())
+        }
+    }
+</%helpers:shorthand>
+
+<%helpers:shorthand
+    name="place-items"
+    engines="gecko"
+    sub_properties="align-items justify-items"
+    spec="https://drafts.csswg.org/css-align/#place-items-property"
+>
+    use crate::values::specified::align::{AlignItems, JustifyItems};
+    use crate::parser::Parse;
+
+    impl From<AlignItems> for JustifyItems {
+        fn from(align: AlignItems) -> JustifyItems {
+            JustifyItems(align.0)
+        }
+    }
+
+    pub fn parse_value<'i, 't>(
+        context: &ParserContext,
+        input: &mut Parser<'i, 't>,
+    ) -> Result<Longhands, ParseError<'i>> {
+        let align = AlignItems::parse(context, input)?;
+        let justify =
+            input.try_parse(|input| JustifyItems::parse(context, input))
+                 .unwrap_or_else(|_| JustifyItems::from(align));
+
+        Ok(expanded! {
+            align_items: align,
+            justify_items: justify,
+        })
+    }
+
+    impl<'a> ToCss for LonghandsToSerialize<'a> {
+        fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result where W: fmt::Write {
+            self.align_items.to_css(dest)?;
+            if self.align_items.0 != self.justify_items.0 {
+                dest.write_char(' ')?;
+                self.justify_items.to_css(dest)?;
+            }
+
+            Ok(())
+        }
+    }
+</%helpers:shorthand>
+
+// See https://github.com/w3c/csswg-drafts/issues/3525 for the quirks stuff.
+${helpers.four_sides_shorthand(
+    "inset",
+    "%s",
+    "specified::LengthPercentageOrAuto::parse",
+    engines="gecko servo-2013",
+    spec="https://drafts.csswg.org/css-logical/#propdef-inset",
+    allow_quirks="No",
+)}
+
+${helpers.two_properties_shorthand(
+    "inset-block",
+    "inset-block-start",
+    "inset-block-end",
+    "specified::LengthPercentageOrAuto::parse",
+    engines="gecko servo-2013",
+    spec="https://drafts.csswg.org/css-logical/#propdef-inset-block"
+)}
+
+${helpers.two_properties_shorthand(
+    "inset-inline",
+    "inset-inline-start",
+    "inset-inline-end",
+    "specified::LengthPercentageOrAuto::parse",
+    engines="gecko servo-2013",
+    spec="https://drafts.csswg.org/css-logical/#propdef-inset-inline"
+)}
+
+${helpers.two_properties_shorthand(
+    "contain-intrinsic-size",
+    "contain-intrinsic-width",
+    "contain-intrinsic-height",
+    engines="gecko",
+    gecko_pref="layout.css.contain-intrinsic-size.enabled",
+    spec="https://drafts.csswg.org/css-sizing-4/#intrinsic-size-override",
+)}