servo/components/style/selector_matching.rs
2015-06-26 12:35:08 -07:00

305 lines
12 KiB
Rust
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

/* 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/. */
use url::Url;
use selectors::bloom::BloomFilter;
use selectors::matching::{SelectorMap, Rule};
use selectors::matching::DeclarationBlock as GenericDeclarationBlock;
use selectors::parser::PseudoElement;
use selectors::Element;
use std::process;
use smallvec::VecLike;
use util::resource_files::read_resource_file;
use legacy::PresentationalHintSynthesis;
use media_queries::Device;
use node::TElementAttributes;
use properties::{PropertyDeclaration, PropertyDeclarationBlock};
use stylesheets::{Stylesheet, CSSRuleIteratorExt, Origin};
use viewport::{ViewportConstraints, ViewportRuleCascade};
pub type DeclarationBlock = GenericDeclarationBlock<Vec<PropertyDeclaration>>;
pub struct Stylist {
// List of stylesheets (including all media rules)
stylesheets: Vec<Stylesheet>,
// Device that the stylist is currently evaluating against.
pub device: Device,
// If true, a stylesheet has been added or the device has
// changed, and the stylist needs to be updated.
is_dirty: bool,
// The current selector maps, after evaluating media
// rules against the current device.
element_map: PerPseudoElementSelectorMap,
before_map: PerPseudoElementSelectorMap,
after_map: PerPseudoElementSelectorMap,
rules_source_order: usize,
}
impl Stylist {
#[inline]
pub fn new(device: Device) -> Stylist {
let mut stylist = Stylist {
stylesheets: vec!(),
device: device,
is_dirty: true,
element_map: PerPseudoElementSelectorMap::new(),
before_map: PerPseudoElementSelectorMap::new(),
after_map: PerPseudoElementSelectorMap::new(),
rules_source_order: 0,
};
// FIXME: Add iso-8859-9.css when the documents encoding is ISO-8859-8.
// FIXME: presentational-hints.css should be at author origin with zero specificity.
// (Does it make a difference?)
for &filename in ["user-agent.css", "servo.css", "presentational-hints.css"].iter() {
match read_resource_file(&[filename]) {
Ok(res) => {
let ua_stylesheet = Stylesheet::from_bytes(
&res,
Url::parse(&format!("chrome:///{:?}", filename)).unwrap(),
None,
None,
Origin::UserAgent);
stylist.add_stylesheet(ua_stylesheet);
}
Err(..) => {
error!("Stylist::new() failed at loading {}!", filename);
process::exit(1);
}
}
}
stylist
}
pub fn constrain_viewport(&self) -> Option<ViewportConstraints> {
let cascaded_rule = self.stylesheets.iter()
.flat_map(|s| s.effective_rules(&self.device).viewport())
.cascade();
ViewportConstraints::maybe_new(self.device.viewport_size, &cascaded_rule)
}
pub fn update(&mut self) -> bool {
if self.is_dirty {
self.element_map = PerPseudoElementSelectorMap::new();
self.before_map = PerPseudoElementSelectorMap::new();
self.after_map = PerPseudoElementSelectorMap::new();
self.rules_source_order = 0;
for stylesheet in self.stylesheets.iter() {
let (mut element_map, mut before_map, mut after_map) = match stylesheet.origin {
Origin::UserAgent => (
&mut self.element_map.user_agent,
&mut self.before_map.user_agent,
&mut self.after_map.user_agent,
),
Origin::Author => (
&mut self.element_map.author,
&mut self.before_map.author,
&mut self.after_map.author,
),
Origin::User => (
&mut self.element_map.user,
&mut self.before_map.user,
&mut self.after_map.user,
),
};
let mut rules_source_order = self.rules_source_order;
// Take apart the StyleRule into individual Rules and insert
// them into the SelectorMap of that priority.
macro_rules! append(
($style_rule: ident, $priority: ident) => {
if $style_rule.declarations.$priority.len() > 0 {
for selector in $style_rule.selectors.iter() {
let map = match selector.pseudo_element {
None => &mut element_map,
Some(PseudoElement::Before) => &mut before_map,
Some(PseudoElement::After) => &mut after_map,
};
map.$priority.insert(Rule {
selector: selector.compound_selectors.clone(),
declarations: DeclarationBlock {
specificity: selector.specificity,
declarations: $style_rule.declarations.$priority.clone(),
source_order: rules_source_order,
},
});
}
}
};
);
for style_rule in stylesheet.effective_rules(&self.device).style() {
append!(style_rule, normal);
append!(style_rule, important);
rules_source_order += 1;
}
self.rules_source_order = rules_source_order;
}
self.is_dirty = false;
return true;
}
false
}
pub fn set_device(&mut self, device: Device) {
let is_dirty = self.is_dirty || self.stylesheets.iter()
.flat_map(|stylesheet| stylesheet.rules().media())
.any(|media_rule| media_rule.evaluate(&self.device) != media_rule.evaluate(&device));
self.device = device;
self.is_dirty |= is_dirty;
}
pub fn add_quirks_mode_stylesheet(&mut self) {
match read_resource_file(&["quirks-mode.css"]) {
Ok(res) => {
self.add_stylesheet(Stylesheet::from_bytes(
&res,
Url::parse("chrome:///quirks-mode.css").unwrap(),
None,
None,
Origin::UserAgent));
}
Err(..) => {
error!("Stylist::add_quirks_mode_stylesheet() failed at loading 'quirks-mode.css'!");
process::exit(1);
}
}
}
pub fn add_stylesheet(&mut self, stylesheet: Stylesheet) {
self.stylesheets.push(stylesheet);
self.is_dirty = true;
}
/// Returns the applicable CSS declarations for the given element. This corresponds to
/// `ElementRuleCollector` in WebKit.
///
/// The returned boolean indicates whether the style is *shareable*; that is, whether the
/// matched selectors are simple enough to allow the matching logic to be reduced to the logic
/// in `css::matching::PrivateMatchMethods::candidate_element_allows_for_style_sharing`.
pub fn push_applicable_declarations<E,V>(
&self,
element: &E,
parent_bf: &Option<Box<BloomFilter>>,
style_attribute: Option<&PropertyDeclarationBlock>,
pseudo_element: Option<PseudoElement>,
applicable_declarations: &mut V)
-> bool
where E: Element + TElementAttributes,
V: VecLike<DeclarationBlock> {
assert!(!self.is_dirty);
assert!(style_attribute.is_none() || pseudo_element.is_none(),
"Style attributes do not apply to pseudo-elements");
let map = match pseudo_element {
None => &self.element_map,
Some(PseudoElement::Before) => &self.before_map,
Some(PseudoElement::After) => &self.after_map,
};
let mut shareable = true;
// Step 1: Normal user-agent rules.
map.user_agent.normal.get_all_matching_rules(element,
parent_bf,
applicable_declarations,
&mut shareable);
// Step 2: Presentational hints.
self.synthesize_presentational_hints_for_legacy_attributes(element,
applicable_declarations,
&mut shareable);
// Step 3: User and author normal rules.
map.user.normal.get_all_matching_rules(element,
parent_bf,
applicable_declarations,
&mut shareable);
map.author.normal.get_all_matching_rules(element,
parent_bf,
applicable_declarations,
&mut shareable);
// Step 4: Normal style attributes.
style_attribute.map(|sa| {
shareable = false;
applicable_declarations.push(
GenericDeclarationBlock::from_declarations(sa.normal.clone()))
});
// Step 5: Author-supplied `!important` rules.
map.author.important.get_all_matching_rules(element,
parent_bf,
applicable_declarations,
&mut shareable);
// Step 6: `!important` style attributes.
style_attribute.map(|sa| {
shareable = false;
applicable_declarations.push(
GenericDeclarationBlock::from_declarations(sa.important.clone()))
});
// Step 7: User and UA `!important` rules.
map.user.important.get_all_matching_rules(element,
parent_bf,
applicable_declarations,
&mut shareable);
map.user_agent.important.get_all_matching_rules(element,
parent_bf,
applicable_declarations,
&mut shareable);
shareable
}
pub fn is_dirty(&self) -> bool {
self.is_dirty
}
}
struct PerOriginSelectorMap {
normal: SelectorMap<Vec<PropertyDeclaration>>,
important: SelectorMap<Vec<PropertyDeclaration>>,
}
impl PerOriginSelectorMap {
#[inline]
fn new() -> PerOriginSelectorMap {
PerOriginSelectorMap {
normal: SelectorMap::new(),
important: SelectorMap::new(),
}
}
}
struct PerPseudoElementSelectorMap {
user_agent: PerOriginSelectorMap,
author: PerOriginSelectorMap,
user: PerOriginSelectorMap,
}
impl PerPseudoElementSelectorMap {
#[inline]
fn new() -> PerPseudoElementSelectorMap {
PerPseudoElementSelectorMap {
user_agent: PerOriginSelectorMap::new(),
author: PerOriginSelectorMap::new(),
user: PerOriginSelectorMap::new(),
}
}
}