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/* 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/. */
//! Specified types for legacy Gecko-only properties.
use crate::parser::{Parse, ParserContext};
use crate::values::computed::{self, Length, LengthPercentage};
use crate::values::generics::rect::Rect;
use cssparser::{Parser, Token};
use std::fmt;
use style_traits::values::SequenceWriter;
use style_traits::{CssWriter, ParseError, StyleParseErrorKind, ToCss};
fn parse_pixel_or_percent<'i, 't>(
_context: &ParserContext,
input: &mut Parser<'i, 't>,
) -> Result<LengthPercentage, ParseError<'i>> {
let location = input.current_source_location();
let token = input.next()?;
let value = match *token {
Token::Dimension {
value, ref unit, ..
} => {
match_ignore_ascii_case! { unit,
"px" => Ok(LengthPercentage::new_length(Length::new(value))),
_ => Err(()),
}
},
Token::Percentage { unit_value, .. } => Ok(LengthPercentage::new_percent(
computed::Percentage(unit_value),
)),
_ => Err(()),
};
value.map_err(|()| location.new_custom_error(StyleParseErrorKind::UnspecifiedError))
}
/// The value of an IntersectionObserver's rootMargin property.
///
/// Only bare px or percentage values are allowed. Other length units and
/// calc() values are not allowed.
///
/// <https://w3c.github.io/IntersectionObserver/#parse-a-root-margin>
#[repr(transparent)]
pub struct IntersectionObserverRootMargin(pub Rect<LengthPercentage>);
impl Parse for IntersectionObserverRootMargin {
fn parse<'i, 't>(
context: &ParserContext,
input: &mut Parser<'i, 't>,
) -> Result<Self, ParseError<'i>> {
use crate::Zero;
if input.is_exhausted() {
// If there are zero elements in tokens, set tokens to ["0px"].
return Ok(IntersectionObserverRootMargin(Rect::all(
LengthPercentage::zero(),
)));
}
let rect = Rect::parse_with(context, input, parse_pixel_or_percent)?;
Ok(IntersectionObserverRootMargin(rect))
}
}
// Strictly speaking this is not ToCss. It's serializing for DOM. But
// we can just reuse the infrastructure of this.
//
// <https://w3c.github.io/IntersectionObserver/#dom-intersectionobserver-rootmargin>
impl ToCss for IntersectionObserverRootMargin {
fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result
where
W: fmt::Write,
{
// We cannot use the ToCss impl of Rect, because that would
// merge items when they are equal. We want to list them all.
let mut writer = SequenceWriter::new(dest, " ");
let rect = &self.0;
writer.item(&rect.0)?;
writer.item(&rect.1)?;
writer.item(&rect.2)?;
writer.item(&rect.3)
}
}
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