servo/components/style/properties/shorthand/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 http://mozilla.org/MPL/2.0/. */

<%namespace name="helpers" file="/helpers.mako.rs" />

<%helpers:shorthand name="list-style"
                    sub_properties="list-style-image list-style-position list-style-type">
    use properties::longhands::{list_style_image, list_style_position, list_style_type};

    pub fn parse_value(context: &ParserContext, input: &mut Parser) -> Result<Longhands, ()> {
        // `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(|input| input.expect_ident_matching("none")).is_ok() {
                nones = nones + 1;
                if nones > 2 {
                    return Err(())
                }
                any = true;
                continue
            }

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

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

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

        // 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.
        match (any, nones, list_style_type, image) {
            (true, 2, None, None) => {
                Ok(Longhands {
                    list_style_position: position,
                    list_style_image: Some(list_style_image::SpecifiedValue::None),
                    list_style_type: Some(list_style_type::SpecifiedValue::none),
                })
            }
            (true, 1, None, Some(image)) => {
                Ok(Longhands {
                    list_style_position: position,
                    list_style_image: Some(image),
                    list_style_type: Some(list_style_type::SpecifiedValue::none),
                })
            }
            (true, 1, Some(list_style_type), None) => {
                Ok(Longhands {
                    list_style_position: position,
                    list_style_image: Some(list_style_image::SpecifiedValue::None),
                    list_style_type: Some(list_style_type),
                })
            }
            (true, 1, None, None) => {
                Ok(Longhands {
                    list_style_position: position,
                    list_style_image: Some(list_style_image::SpecifiedValue::None),
                    list_style_type: Some(list_style_type::SpecifiedValue::none),
                })
            }
            (true, 0, list_style_type, image) => {
                Ok(Longhands {
                    list_style_position: position,
                    list_style_image: image,
                    list_style_type: list_style_type,
                })
            }
            _ => Err(()),
        }
    }

    impl<'a> ToCss for LonghandsToSerialize<'a>  {
        fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
            match *self.list_style_position {
                DeclaredValue::Initial => try!(write!(dest, "outside")),
                _ => try!(self.list_style_position.to_css(dest))
            }

            try!(write!(dest, " "));

            match *self.list_style_image {
                DeclaredValue::Initial => try!(write!(dest, "none")),
                _ => try!(self.list_style_image.to_css(dest))
            };

            try!(write!(dest, " "));

            match *self.list_style_type {
                DeclaredValue::Initial => write!(dest, "disc"),
                _ => self.list_style_type.to_css(dest)
            }
        }
    }
</%helpers:shorthand>