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Hoist specificity computation into a new private builder module.
This patch doesn't modify any of the code because making a few things pub. I did this first to make the next patch easier to audit. MozReview-Commit-ID: 7PYxoS5bVGN
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,141 @@ | ||
| /* 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/. */ | ||
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| use parser::{Component, SelectorImpl, SelectorIter}; | ||
| use std::cmp; | ||
| use std::ops::Add; | ||
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| #[derive(Copy, Clone, Debug, Eq, PartialEq)] | ||
| pub struct SpecificityAndFlags(pub u32); | ||
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| pub const HAS_PSEUDO_BIT: u32 = 1 << 30; | ||
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| impl SpecificityAndFlags { | ||
| pub fn specificity(&self) -> u32 { | ||
| self.0 & !HAS_PSEUDO_BIT | ||
| } | ||
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| pub fn has_pseudo_element(&self) -> bool { | ||
| (self.0 & HAS_PSEUDO_BIT) != 0 | ||
| } | ||
| } | ||
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| const MAX_10BIT: u32 = (1u32 << 10) - 1; | ||
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| #[derive(Clone, Copy, Eq, Ord, PartialEq, PartialOrd)] | ||
| struct Specificity { | ||
| id_selectors: u32, | ||
| class_like_selectors: u32, | ||
| element_selectors: u32, | ||
| } | ||
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| impl Add for Specificity { | ||
| type Output = Specificity; | ||
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| fn add(self, rhs: Specificity) -> Specificity { | ||
| Specificity { | ||
| id_selectors: self.id_selectors + rhs.id_selectors, | ||
| class_like_selectors: | ||
| self.class_like_selectors + rhs.class_like_selectors, | ||
| element_selectors: | ||
| self.element_selectors + rhs.element_selectors, | ||
| } | ||
| } | ||
| } | ||
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| impl Default for Specificity { | ||
| fn default() -> Specificity { | ||
| Specificity { | ||
| id_selectors: 0, | ||
| class_like_selectors: 0, | ||
| element_selectors: 0, | ||
| } | ||
| } | ||
| } | ||
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| impl From<u32> for Specificity { | ||
| fn from(value: u32) -> Specificity { | ||
| assert!(value <= MAX_10BIT << 20 | MAX_10BIT << 10 | MAX_10BIT); | ||
| Specificity { | ||
| id_selectors: value >> 20, | ||
| class_like_selectors: (value >> 10) & MAX_10BIT, | ||
| element_selectors: value & MAX_10BIT, | ||
| } | ||
| } | ||
| } | ||
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| impl From<Specificity> for u32 { | ||
| fn from(specificity: Specificity) -> u32 { | ||
| cmp::min(specificity.id_selectors, MAX_10BIT) << 20 | ||
| | cmp::min(specificity.class_like_selectors, MAX_10BIT) << 10 | ||
| | cmp::min(specificity.element_selectors, MAX_10BIT) | ||
| } | ||
| } | ||
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| pub fn specificity<Impl>(iter: SelectorIter<Impl>) -> u32 | ||
| where Impl: SelectorImpl | ||
| { | ||
| complex_selector_specificity(iter).into() | ||
| } | ||
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| fn complex_selector_specificity<Impl>(mut iter: SelectorIter<Impl>) | ||
| -> Specificity | ||
| where Impl: SelectorImpl | ||
| { | ||
| fn simple_selector_specificity<Impl>(simple_selector: &Component<Impl>, | ||
| specificity: &mut Specificity) | ||
| where Impl: SelectorImpl | ||
| { | ||
| match *simple_selector { | ||
| Component::Combinator(..) => unreachable!(), | ||
| Component::PseudoElement(..) | | ||
| Component::LocalName(..) => { | ||
| specificity.element_selectors += 1 | ||
| } | ||
| Component::ID(..) => { | ||
| specificity.id_selectors += 1 | ||
| } | ||
| Component::Class(..) | | ||
| Component::AttributeInNoNamespace { .. } | | ||
| Component::AttributeInNoNamespaceExists { .. } | | ||
| Component::AttributeOther(..) | | ||
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| Component::FirstChild | Component::LastChild | | ||
| Component::OnlyChild | Component::Root | | ||
| Component::Empty | | ||
| Component::NthChild(..) | | ||
| Component::NthLastChild(..) | | ||
| Component::NthOfType(..) | | ||
| Component::NthLastOfType(..) | | ||
| Component::FirstOfType | Component::LastOfType | | ||
| Component::OnlyOfType | | ||
| Component::NonTSPseudoClass(..) => { | ||
| specificity.class_like_selectors += 1 | ||
| } | ||
| Component::ExplicitUniversalType | | ||
| Component::ExplicitAnyNamespace | | ||
| Component::ExplicitNoNamespace | | ||
| Component::DefaultNamespace(..) | | ||
| Component::Namespace(..) => { | ||
| // Does not affect specificity | ||
| } | ||
| Component::Negation(ref negated) => { | ||
| for ss in negated.iter() { | ||
| simple_selector_specificity(&ss, specificity); | ||
| } | ||
| } | ||
| } | ||
| } | ||
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| let mut specificity = Default::default(); | ||
| loop { | ||
| for simple_selector in &mut iter { | ||
| simple_selector_specificity(&simple_selector, &mut specificity); | ||
| } | ||
| if iter.next_sequence().is_none() { | ||
| break; | ||
| } | ||
| } | ||
| specificity | ||
| } |
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