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61 lines
2.6 KiB
Rust
61 lines
2.6 KiB
Rust
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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//! Legacy presentational attributes defined in the HTML5 specification: `<td width>`,
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//! `<input size>`, and so forth.
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use std::sync::Arc;
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use node::TElementAttributes;
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use properties::PropertyDeclaration;
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use selector_matching::Stylist;
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use selectors::Element;
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use selectors::matching::DeclarationBlock;
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use smallvec::VecLike;
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/// Legacy presentational attributes that take a nonnegative integer as defined in HTML5 § 2.4.4.2.
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#[derive(Copy, Clone, PartialEq, Eq)]
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pub enum UnsignedIntegerAttribute {
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/// `<td colspan>`
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ColSpan,
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}
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/// Extension methods for `Stylist` that cause rules to be synthesized for legacy attributes.
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pub trait PresentationalHintSynthesis {
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/// Synthesizes rules from various HTML attributes (mostly legacy junk from HTML4) that confer
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/// *presentational hints* as defined in the HTML5 specification. This handles stuff like
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/// `<body bgcolor>`, `<input size>`, `<td width>`, and so forth.
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///
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/// NB: Beware! If you add an attribute to this list, be sure to add it to
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/// `common_style_affecting_attributes` or `rare_style_affecting_attributes` as appropriate. If
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/// you don't, you risk strange random nondeterministic failures due to false positives in
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/// style sharing.
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fn synthesize_presentational_hints_for_legacy_attributes<E, V>(
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&self, element: &E, matching_rules_list: &mut V, shareable: &mut bool)
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where E: Element + TElementAttributes,
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V: VecLike<DeclarationBlock<Vec<PropertyDeclaration>>>;
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}
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impl PresentationalHintSynthesis for Stylist {
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fn synthesize_presentational_hints_for_legacy_attributes<E, V>(
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&self, element: &E, matching_rules_list: &mut V, shareable: &mut bool)
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where E: Element + TElementAttributes,
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V: VecLike<DeclarationBlock<Vec<PropertyDeclaration>>> {
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let length = matching_rules_list.len();
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element.synthesize_presentational_hints_for_legacy_attributes(matching_rules_list);
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if matching_rules_list.len() != length {
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// Never share style for elements with preshints
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*shareable = false;
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}
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}
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}
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/// A convenience function to create a declaration block from a single declaration. This is
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/// primarily used in `synthesize_rules_for_legacy_attributes`.
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#[inline]
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pub fn from_declaration(rule: PropertyDeclaration) -> DeclarationBlock<Vec<PropertyDeclaration>> {
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DeclarationBlock::from_declarations(Arc::new(vec![rule]))
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}
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