servo/components/style/properties/shorthands/list.mako.rs

/* 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="list-style"
                    engines="gecko servo"
                    sub_properties="list-style-position list-style-image list-style-type"
                    spec="https://drafts.csswg.org/css-lists/#propdef-list-style">
    use crate::properties::longhands::{list_style_image, list_style_position, list_style_type};
    use crate::values::specified::Image;

    pub fn parse_value<'i, 't>(
        context: &ParserContext,
        input: &mut Parser<'i, 't>,
    ) -> Result<Longhands, ParseError<'i>> {
        // `none` is ambiguous until we've finished parsing the shorthands, so we count the number
        // of times we see it.
        let mut nones = 0u8;
        let (mut image, mut position, mut list_style_type, mut any) = (None, None, None, false);
        loop {
            if input.try_parse(|input| input.expect_ident_matching("none")).is_ok() {
                nones = nones + 1;
                if nones > 2 {
                    return Err(input.new_custom_error(SelectorParseErrorKind::UnexpectedIdent("none".into())))
                }
                any = true;
                continue
            }

            if image.is_none() {
                if let Ok(value) = input.try_parse(|input| list_style_image::parse(context, input)) {
                    image = Some(value);
                    any = true;
                    continue
                }
            }

            if position.is_none() {
                if let Ok(value) = input.try_parse(|input| list_style_position::parse(context, input)) {
                    position = Some(value);
                    any = true;
                    continue
                }
            }

            // list-style-type must be checked the last, because it accepts
            // arbitrary identifier for custom counter style, and thus may
            // affect values of list-style-position.
            if list_style_type.is_none() {
                if let Ok(value) = input.try_parse(|input| list_style_type::parse(context, input)) {
                    list_style_type = Some(value);
                    any = true;
                    continue
                }
            }
            break
        }

        let position = unwrap_or_initial!(list_style_position, position);

        // If there are two `none`s, then we can't have a type or image; if there is one `none`,
        // then we can't have both a type *and* an image; if there is no `none` then we're fine as
        // long as we parsed something.
        use self::list_style_type::SpecifiedValue as ListStyleType;
        match (any, nones, list_style_type, image) {
            (true, 2, None, None) => {
                Ok(expanded! {
                    list_style_position: position,
                    list_style_image: Image::None,
                    list_style_type: ListStyleType::None,
                })
            }
            (true, 1, None, Some(image)) => {
                Ok(expanded! {
                    list_style_position: position,
                    list_style_image: image,
                    list_style_type: ListStyleType::None,
                })
            }
            (true, 1, Some(list_style_type), None) => {
                Ok(expanded! {
                    list_style_position: position,
                    list_style_image: Image::None,
                    list_style_type: list_style_type,
                })
            }
            (true, 1, None, None) => {
                Ok(expanded! {
                    list_style_position: position,
                    list_style_image: Image::None,
                    list_style_type: ListStyleType::None,
                })
            }
            (true, 0, list_style_type, image) => {
                Ok(expanded! {
                    list_style_position: position,
                    list_style_image: unwrap_or_initial!(list_style_image, image),
                    list_style_type: unwrap_or_initial!(list_style_type),
                })
            }
            _ => Err(input.new_custom_error(StyleParseErrorKind::UnspecifiedError)),
        }
    }

    impl<'a> ToCss for LonghandsToSerialize<'a>  {
        fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result where W: fmt::Write {
            use longhands::list_style_position::SpecifiedValue as ListStylePosition;
            use longhands::list_style_type::SpecifiedValue as ListStyleType;
            use longhands::list_style_image::SpecifiedValue as ListStyleImage;
            let mut have_one_non_initial_value = false;
            #[cfg(feature = "gecko")]
            let position_is_initial = self.list_style_position == &ListStylePosition::Outside;
            #[cfg(feature = "servo")]
            let position_is_initial = self.list_style_position == Some(&ListStylePosition::Outside);
            if !position_is_initial {
                self.list_style_position.to_css(dest)?;
                have_one_non_initial_value = true;
            }
            if self.list_style_image != &ListStyleImage::None {
                if have_one_non_initial_value {
                    dest.write_str(" ")?;
                }
                self.list_style_image.to_css(dest)?;
                have_one_non_initial_value = true;
            }
            #[cfg(feature = "gecko")]
            let type_is_initial = self.list_style_type == &ListStyleType::disc();
            #[cfg(feature = "servo")]
            let type_is_initial = self.list_style_type == &ListStyleType::Disc;
            if !type_is_initial {
                if have_one_non_initial_value {
                    dest.write_str(" ")?;
                }
                self.list_style_type.to_css(dest)?;
                have_one_non_initial_value = true;
            }
            if !have_one_non_initial_value {
                self.list_style_position.to_css(dest)?;
            }
            Ok(())
        }
    }
</%helpers:shorthand>