servo/components/style/legacy.rs
Patrick Walton 4b9cd4e65d layout: Implement <table width> and <center>.
Improves Hacker News.
2015-05-11 12:53:45 -07:00

258 lines
13 KiB
Rust

/* 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/. */
//! Legacy presentational attributes defined in the HTML5 specification: `<td width>`,
//! `<input size>`, and so forth.
use std::sync::Arc;
use selectors::tree::{TElement, TNode};
use selectors::matching::DeclarationBlock;
use node::TElementAttributes;
use values::{CSSFloat, specified};
use properties::DeclaredValue::SpecifiedValue;
use properties::PropertyDeclaration;
use properties::longhands::{self, border_spacing};
use selector_matching::Stylist;
use util::geometry::Au;
use util::smallvec::VecLike;
use util::str::LengthOrPercentageOrAuto;
/// Legacy presentational attributes that take a length as defined in HTML5 § 2.4.4.4.
#[derive(Copy, Clone, PartialEq, Eq)]
pub enum LengthAttribute {
/// `<td width>`
Width,
}
/// Legacy presentational attributes that take an integer as defined in HTML5 § 2.4.4.2.
#[derive(Copy, Clone, PartialEq, Eq)]
pub enum IntegerAttribute {
/// `<input size>`
Size,
Cols,
Rows,
}
/// Legacy presentational attributes that take a nonnegative integer as defined in HTML5 § 2.4.4.2.
#[derive(Copy, Clone, PartialEq, Eq)]
pub enum UnsignedIntegerAttribute {
/// `<td border>`
Border,
/// `<table cellspacing>`
CellSpacing,
/// `<td colspan>`
ColSpan,
}
/// Extension methods for `Stylist` that cause rules to be synthesized for legacy attributes.
pub trait PresentationalHintSynthesis {
/// Synthesizes rules from various HTML attributes (mostly legacy junk from HTML4) that confer
/// *presentational hints* as defined in the HTML5 specification. This handles stuff like
/// `<body bgcolor>`, `<input size>`, `<td width>`, and so forth.
///
/// NB: Beware! If you add an attribute to this list, be sure to add it to
/// `common_style_affecting_attributes` or `rare_style_affecting_attributes` as appropriate. If
/// you don't, you risk strange random nondeterministic failures due to false positives in
/// style sharing.
fn synthesize_presentational_hints_for_legacy_attributes<'a,N,V>(
&self,
node: &N,
matching_rules_list: &mut V,
shareable: &mut bool)
where N: TNode<'a>,
N::Element: TElementAttributes<'a>,
V: VecLike<DeclarationBlock<Vec<PropertyDeclaration>>>;
/// Synthesizes rules for the legacy `border` attribute.
fn synthesize_presentational_hint_for_legacy_border_attribute<'a,E,V>(
&self,
element: E,
matching_rules_list: &mut V,
shareable: &mut bool)
where
E: TElement<'a> +
TElementAttributes<'a>,
V: VecLike<DeclarationBlock<Vec<PropertyDeclaration>>>;
/// Synthesizes rules for the legacy `width` attribute.
fn synthesize_presentational_hint_for_legacy_width_attribute<'a,E,V>(
&self,
element: E,
matching_rules_list: &mut V,
shareable: &mut bool)
where E: TElement<'a> + TElementAttributes<'a>,
V: VecLike<DeclarationBlock<Vec<PropertyDeclaration>>>;
}
impl PresentationalHintSynthesis for Stylist {
fn synthesize_presentational_hints_for_legacy_attributes<'a,N,V>(
&self,
node: &N,
matching_rules_list: &mut V,
shareable: &mut bool)
where N: TNode<'a>,
N::Element: TElementAttributes<'a>,
V: VecLike<DeclarationBlock<Vec<PropertyDeclaration>>> {
let element = node.as_element();
let length = matching_rules_list.len();
element.synthesize_presentational_hints_for_legacy_attributes(matching_rules_list);
if matching_rules_list.len() != length {
// Never share style for elements with preshints
*shareable = false;
}
match element.get_local_name() {
name if *name == atom!("td") => {
self.synthesize_presentational_hint_for_legacy_width_attribute(
element,
matching_rules_list,
shareable);
self.synthesize_presentational_hint_for_legacy_border_attribute(
element,
matching_rules_list,
shareable);
}
name if *name == atom!("table") => {
self.synthesize_presentational_hint_for_legacy_width_attribute(
element,
matching_rules_list,
shareable);
self.synthesize_presentational_hint_for_legacy_border_attribute(
element,
matching_rules_list,
shareable);
match element.get_unsigned_integer_attribute(
UnsignedIntegerAttribute::CellSpacing) {
None => {}
Some(length) => {
let width_value = specified::Length::Absolute(Au::from_px(length as i32));
matching_rules_list.push(from_declaration(
PropertyDeclaration::BorderSpacing(
SpecifiedValue(
border_spacing::SpecifiedValue {
horizontal: width_value,
vertical: width_value,
}))));
*shareable = false
}
}
}
name if *name == atom!("input") => {
// FIXME(pcwalton): More use of atoms, please!
match element.get_attr(&ns!(""), &atom!("type")) {
Some("text") | Some("password") => {
match element.get_integer_attribute(IntegerAttribute::Size) {
Some(value) if value != 0 => {
let value = specified::Length::ServoCharacterWidth(
specified::CharacterWidth(value));
matching_rules_list.push(from_declaration(
PropertyDeclaration::Width(SpecifiedValue(
specified::LengthOrPercentageOrAuto::Length(value)))));
*shareable = false
}
Some(_) | None => {}
}
}
_ => {}
};
}
name if *name == atom!("textarea") => {
match element.get_integer_attribute(IntegerAttribute::Cols) {
Some(value) if value != 0 => {
// TODO(mttr) ServoCharacterWidth uses the size math for <input type="text">, but
// the math for <textarea> is a little different since we need to take
// scrollbar size into consideration (but we don't have a scrollbar yet!)
//
// https://html.spec.whatwg.org/multipage/#textarea-effective-width
let value = specified::Length::ServoCharacterWidth(specified::CharacterWidth(value));
matching_rules_list.push(from_declaration(
PropertyDeclaration::Width(SpecifiedValue(
specified::LengthOrPercentageOrAuto::Length(value)))));
*shareable = false
}
Some(_) | None => {}
}
match element.get_integer_attribute(IntegerAttribute::Rows) {
Some(value) if value != 0 => {
// TODO(mttr) This should take scrollbar size into consideration.
//
// https://html.spec.whatwg.org/multipage/#textarea-effective-height
let value = specified::Length::FontRelative(specified::FontRelativeLength::Em(value as CSSFloat));
matching_rules_list.push(from_declaration(
PropertyDeclaration::Height(SpecifiedValue(
longhands::height::SpecifiedValue(
specified::LengthOrPercentageOrAuto::Length(value))))));
*shareable = false
}
Some(_) | None => {}
}
}
_ => {}
}
}
fn synthesize_presentational_hint_for_legacy_border_attribute<'a,E,V>(
&self,
element: E,
matching_rules_list: &mut V,
shareable: &mut bool)
where
E: TElement<'a> +
TElementAttributes<'a>,
V: VecLike<DeclarationBlock<Vec<PropertyDeclaration>>> {
match element.get_unsigned_integer_attribute(UnsignedIntegerAttribute::Border) {
None => {}
Some(length) => {
let width_value = specified::Length::Absolute(Au::from_px(length as i32));
matching_rules_list.push(from_declaration(
PropertyDeclaration::BorderTopWidth(SpecifiedValue(
longhands::border_top_width::SpecifiedValue(width_value)))));
matching_rules_list.push(from_declaration(
PropertyDeclaration::BorderLeftWidth(SpecifiedValue(
longhands::border_left_width::SpecifiedValue(width_value)))));
matching_rules_list.push(from_declaration(
PropertyDeclaration::BorderBottomWidth(SpecifiedValue(
longhands::border_bottom_width::SpecifiedValue(width_value)))));
matching_rules_list.push(from_declaration(
PropertyDeclaration::BorderRightWidth(SpecifiedValue(
longhands::border_right_width::SpecifiedValue(width_value)))));
*shareable = false
}
}
}
fn synthesize_presentational_hint_for_legacy_width_attribute<'a,E,V>(
&self,
element: E,
matching_rules_list: &mut V,
shareable: &mut bool)
where E: TElement<'a> + TElementAttributes<'a>,
V: VecLike<DeclarationBlock<Vec<PropertyDeclaration>>> {
match element.get_length_attribute(LengthAttribute::Width) {
LengthOrPercentageOrAuto::Auto => {}
LengthOrPercentageOrAuto::Percentage(percentage) => {
let width_value = specified::LengthOrPercentageOrAuto::Percentage(percentage);
matching_rules_list.push(from_declaration(
PropertyDeclaration::Width(SpecifiedValue(width_value))));
*shareable = false
}
LengthOrPercentageOrAuto::Length(length) => {
let width_value = specified::LengthOrPercentageOrAuto::Length(
specified::Length::Absolute(length));
matching_rules_list.push(from_declaration(
PropertyDeclaration::Width(SpecifiedValue(width_value))));
*shareable = false
}
}
}
}
/// A convenience function to create a declaration block from a single declaration. This is
/// primarily used in `synthesize_rules_for_legacy_attributes`.
#[inline]
pub fn from_declaration(rule: PropertyDeclaration) -> DeclarationBlock<Vec<PropertyDeclaration>> {
DeclarationBlock::from_declarations(Arc::new(vec![rule]))
}