mirror of
https://github.com/servo/servo.git
synced 2025-08-06 06:00:15 +01:00
Add a generic PositionValue struct
This commit is contained in:
parent
f4b18643c2
commit
6f062e5857
2 changed files with 115 additions and 0 deletions
|
@ -14,6 +14,7 @@ use super::computed::{Context, ToComputedValue};
|
|||
pub use self::basic_shape::serialize_radius_values;
|
||||
|
||||
pub mod basic_shape;
|
||||
pub mod position;
|
||||
|
||||
#[derive(Clone, PartialEq, Debug)]
|
||||
#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
|
||||
|
|
114
components/style/values/generics/position.rs
Normal file
114
components/style/values/generics/position.rs
Normal file
|
@ -0,0 +1,114 @@
|
|||
/* 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/. */
|
||||
|
||||
//! Generic types for CSS handling of specified and computed values of
|
||||
//! [`position`](https://drafts.csswg.org/css-backgrounds-3/#position)
|
||||
|
||||
use cssparser::Parser;
|
||||
use parser::{Parse, ParserContext};
|
||||
use std::fmt;
|
||||
use style_traits::ToCss;
|
||||
use values::HasViewportPercentage;
|
||||
use values::specified::{LengthOrPercentage, Percentage};
|
||||
|
||||
define_css_keyword_enum!{ Keyword:
|
||||
"center" => Center,
|
||||
"left" => Left,
|
||||
"right" => Right,
|
||||
"top" => Top,
|
||||
"bottom" => Bottom,
|
||||
"x-start" => XStart,
|
||||
"x-end" => XEnd,
|
||||
"y-start" => YStart,
|
||||
"y-end" => YEnd
|
||||
}
|
||||
|
||||
impl From<Keyword> for LengthOrPercentage {
|
||||
fn from(val: Keyword) -> LengthOrPercentage {
|
||||
match val {
|
||||
Keyword::Center => LengthOrPercentage::Percentage(Percentage(0.5)),
|
||||
Keyword::Left | Keyword::Top => LengthOrPercentage::Percentage(Percentage(0.0)),
|
||||
Keyword::Right | Keyword::Bottom => LengthOrPercentage::Percentage(Percentage(1.0)),
|
||||
// FIXME(canaltinova): Support logical keywords
|
||||
Keyword::XStart | Keyword::YStart => LengthOrPercentage::Percentage(Percentage(0.0)),
|
||||
Keyword::XEnd | Keyword::YEnd => LengthOrPercentage::Percentage(Percentage(1.0)),
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
#[derive(Debug, Clone, PartialEq)]
|
||||
#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
|
||||
/// A generic type for representing horizontal or vertical `<position>` value.
|
||||
pub struct PositionValue<L> {
|
||||
/// Even though this is generic, it's always a `<length-percentage>` value.
|
||||
pub position: Option<L>,
|
||||
/// A position keyword.
|
||||
pub keyword: Option<Keyword>,
|
||||
}
|
||||
|
||||
impl<L: HasViewportPercentage> HasViewportPercentage for PositionValue<L> {
|
||||
#[inline]
|
||||
fn has_viewport_percentage(&self) -> bool {
|
||||
self.position.as_ref().map_or(false, |pos| pos.has_viewport_percentage())
|
||||
}
|
||||
}
|
||||
|
||||
impl<L: Parse> PositionValue<L> {
|
||||
/// Internal parsing function which (after parsing) checks the keyword with the
|
||||
/// given function.
|
||||
pub fn parse_internal<F>(context: &ParserContext, input: &mut Parser,
|
||||
mut is_allowed_keyword: F) -> Result<PositionValue<L>, ()>
|
||||
where F: FnMut(Keyword) -> bool
|
||||
{
|
||||
let (mut pos, mut keyword) = (None, None);
|
||||
for _ in 0..2 {
|
||||
if let Ok(l) = input.try(|i| L::parse(context, i)) {
|
||||
if pos.is_some() {
|
||||
return Err(())
|
||||
}
|
||||
|
||||
pos = Some(l);
|
||||
}
|
||||
|
||||
if let Ok(k) = input.try(Keyword::parse) {
|
||||
if keyword.is_some() || !is_allowed_keyword(k) {
|
||||
return Err(())
|
||||
}
|
||||
|
||||
keyword = Some(k);
|
||||
}
|
||||
}
|
||||
|
||||
if pos.is_some() {
|
||||
if let Some(Keyword::Center) = keyword {
|
||||
return Err(()) // "center" and <length> is not allowed
|
||||
}
|
||||
} else if keyword.is_none() {
|
||||
return Err(()) // at least one value is necessary
|
||||
}
|
||||
|
||||
Ok(PositionValue {
|
||||
position: pos,
|
||||
keyword: keyword,
|
||||
})
|
||||
}
|
||||
}
|
||||
|
||||
impl<L: ToCss> ToCss for PositionValue<L> {
|
||||
fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
|
||||
if let Some(keyword) = self.keyword {
|
||||
keyword.to_css(dest)?;
|
||||
}
|
||||
|
||||
if let Some(ref position) = self.position {
|
||||
if self.keyword.is_some() {
|
||||
dest.write_str(" ")?;
|
||||
}
|
||||
|
||||
position.to_css(dest)?;
|
||||
}
|
||||
|
||||
Ok(())
|
||||
}
|
||||
}
|
Loading…
Add table
Add a link
Reference in a new issue