servo/components/style/values/specified/text.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/. */

//! Specified types for text properties.

use cssparser::{Parser, Token};
use parser::{Parse, ParserContext};
use selectors::parser::SelectorParseErrorKind;
use std::ascii::AsciiExt;
use style_traits::ParseError;
use values::computed::{Context, ToComputedValue};
use values::computed::text::LineHeight as ComputedLineHeight;
use values::computed::text::TextOverflow as ComputedTextOverflow;
use values::generics::text::InitialLetter as GenericInitialLetter;
use values::generics::text::LineHeight as GenericLineHeight;
use values::generics::text::Spacing;
use values::specified::{AllowQuirks, Integer, NonNegativeNumber, Number};
use values::specified::length::{FontRelativeLength, Length, LengthOrPercentage, NoCalcLength};
use values::specified::length::NonNegativeLengthOrPercentage;

/// A specified type for the `initial-letter` property.
pub type InitialLetter = GenericInitialLetter<Number, Integer>;

/// A specified value for the `letter-spacing` property.
pub type LetterSpacing = Spacing<Length>;

/// A specified value for the `word-spacing` property.
pub type WordSpacing = Spacing<LengthOrPercentage>;

/// A specified value for the `line-height` property.
pub type LineHeight = GenericLineHeight<NonNegativeNumber, NonNegativeLengthOrPercentage>;

impl Parse for InitialLetter {
    fn parse<'i, 't>(context: &ParserContext, input: &mut Parser<'i, 't>) -> Result<Self, ParseError<'i>> {
        if input.try(|i| i.expect_ident_matching("normal")).is_ok() {
            return Ok(GenericInitialLetter::Normal);
        }
        let size = Number::parse_at_least_one(context, input)?;
        let sink = input.try(|i| Integer::parse_positive(context, i)).ok();
        Ok(GenericInitialLetter::Specified(size, sink))
    }
}

impl Parse for LetterSpacing {
    fn parse<'i, 't>(context: &ParserContext, input: &mut Parser<'i, 't>) -> Result<Self, ParseError<'i>> {
        Spacing::parse_with(context, input, |c, i| {
            Length::parse_quirky(c, i, AllowQuirks::Yes)
        })
    }
}

impl Parse for WordSpacing {
    fn parse<'i, 't>(context: &ParserContext, input: &mut Parser<'i, 't>) -> Result<Self, ParseError<'i>> {
        Spacing::parse_with(context, input, |c, i| {
            LengthOrPercentage::parse_quirky(c, i, AllowQuirks::Yes)
        })
    }
}

impl Parse for LineHeight {
    fn parse<'i, 't>(context: &ParserContext, input: &mut Parser<'i, 't>) -> Result<Self, ParseError<'i>> {
        if let Ok(number) = input.try(|i| NonNegativeNumber::parse(context, i)) {
            return Ok(GenericLineHeight::Number(number))
        }
        if let Ok(nlop) = input.try(|i| NonNegativeLengthOrPercentage::parse(context, i)) {
            return Ok(GenericLineHeight::Length(nlop))
        }
        let location = input.current_source_location();
        let ident = input.expect_ident()?;
        match ident {
            ref ident if ident.eq_ignore_ascii_case("normal") => {
                Ok(GenericLineHeight::Normal)
            },
            #[cfg(feature = "gecko")]
            ref ident if ident.eq_ignore_ascii_case("-moz-block-height") => {
                Ok(GenericLineHeight::MozBlockHeight)
            },
            ident => Err(location.new_custom_error(SelectorParseErrorKind::UnexpectedIdent(ident.clone()))),
        }
    }
}

impl ToComputedValue for LineHeight {
    type ComputedValue = ComputedLineHeight;

    #[inline]
    fn to_computed_value(&self, context: &Context) -> Self::ComputedValue {
        use values::computed::Length as ComputedLength;
        use values::specified::length::FontBaseSize;
        match *self {
            GenericLineHeight::Normal => {
                GenericLineHeight::Normal
            },
            #[cfg(feature = "gecko")]
            GenericLineHeight::MozBlockHeight => {
                GenericLineHeight::MozBlockHeight
            },
            GenericLineHeight::Number(number) => {
                GenericLineHeight::Number(number.to_computed_value(context))
            },
            GenericLineHeight::Length(ref non_negative_lop) => {
                let result = match non_negative_lop.0 {
                    LengthOrPercentage::Length(NoCalcLength::Absolute(ref abs)) => {
                        context.maybe_zoom_text(abs.to_computed_value(context).into()).0
                    }
                    LengthOrPercentage::Length(ref length) => {
                        length.to_computed_value(context)
                    },
                    LengthOrPercentage::Percentage(ref p) => {
                        FontRelativeLength::Em(p.0)
                            .to_computed_value(
                                context,
                                FontBaseSize::CurrentStyle,
                            )
                    }
                    LengthOrPercentage::Calc(ref calc) => {
                        let computed_calc =
                            calc.to_computed_value_zoomed(context, FontBaseSize::CurrentStyle);
                        let font_relative_length =
                            FontRelativeLength::Em(computed_calc.percentage())
                                .to_computed_value(
                                    context,
                                    FontBaseSize::CurrentStyle,
                                ).px();

                        let absolute_length = computed_calc.unclamped_length().px();
                        let pixel = computed_calc
                            .clamping_mode
                            .clamp(absolute_length + font_relative_length);
                        ComputedLength::new(pixel)
                    }
                };
                GenericLineHeight::Length(result.into())
            }
        }
    }

    #[inline]
    fn from_computed_value(computed: &Self::ComputedValue) -> Self {
        match *computed {
            GenericLineHeight::Normal => {
                GenericLineHeight::Normal
            },
            #[cfg(feature = "gecko")]
            GenericLineHeight::MozBlockHeight => {
                GenericLineHeight::MozBlockHeight
            },
            GenericLineHeight::Number(ref number) => {
                GenericLineHeight::Number(NonNegativeNumber::from_computed_value(number))
            },
            GenericLineHeight::Length(ref length) => {
                GenericLineHeight::Length(NoCalcLength::from_computed_value(&length.0).into())
            }
        }
    }
}

/// A generic value for the `text-overflow` property.
#[derive(Clone, Debug, Eq, MallocSizeOf, PartialEq, ToCss)]
pub enum TextOverflowSide {
    /// Clip inline content.
    Clip,
    /// Render ellipsis to represent clipped inline content.
    Ellipsis,
    /// Render a given string to represent clipped inline content.
    String(Box<str>),
}

impl Parse for TextOverflowSide {
    fn parse<'i, 't>(_context: &ParserContext, input: &mut Parser<'i, 't>)
                        -> Result<TextOverflowSide, ParseError<'i>> {
        let location = input.current_source_location();
        match *input.next()? {
            Token::Ident(ref ident) => {
                match_ignore_ascii_case! { ident,
                    "clip" => Ok(TextOverflowSide::Clip),
                    "ellipsis" => Ok(TextOverflowSide::Ellipsis),
                    _ => Err(location.new_custom_error(
                        SelectorParseErrorKind::UnexpectedIdent(ident.clone())
                    ))
                }
            }
            Token::QuotedString(ref v) => {
                Ok(TextOverflowSide::String(v.as_ref().to_owned().into_boxed_str()))
            }
            ref t => Err(location.new_unexpected_token_error(t.clone())),
        }
    }
}

#[derive(Clone, Debug, Eq, MallocSizeOf, PartialEq, ToCss)]
/// text-overflow. Specifies rendering when inline content overflows its line box edge.
pub struct TextOverflow {
    /// First value. Applies to end line box edge if no second is supplied; line-left edge otherwise.
    pub first: TextOverflowSide,
    /// Second value. Applies to the line-right edge if supplied.
    pub second: Option<TextOverflowSide>,
}

impl Parse for TextOverflow {
    fn parse<'i, 't>(context: &ParserContext, input: &mut Parser<'i, 't>) -> Result<TextOverflow, ParseError<'i>> {
        let first = TextOverflowSide::parse(context, input)?;
        let second = input.try(|input| TextOverflowSide::parse(context, input)).ok();
        Ok(TextOverflow { first, second })
    }
}

impl ToComputedValue for TextOverflow {
    type ComputedValue = ComputedTextOverflow;

    #[inline]
    fn to_computed_value(&self, _context: &Context) -> Self::ComputedValue {
        if let Some(ref second) = self.second {
            Self::ComputedValue {
                first: self.first.clone(),
                second: second.clone(),
                sides_are_logical: false,
            }
        } else {
            Self::ComputedValue {
                first: TextOverflowSide::Clip,
                second: self.first.clone(),
                sides_are_logical: true,
            }
        }
    }

    #[inline]
    fn from_computed_value(computed: &Self::ComputedValue) -> Self {
        if computed.sides_are_logical {
            assert!(computed.first == TextOverflowSide::Clip);
            TextOverflow {
                first: computed.second.clone(),
                second: None,
            }
        } else {
            TextOverflow {
                first: computed.first.clone(),
                second: Some(computed.second.clone()),
            }
        }
    }
}