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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 09:22:09 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 09:22:09 +0000 |
commit | 43a97878ce14b72f0981164f87f2e35e14151312 (patch) | |
tree | 620249daf56c0258faa40cbdcf9cfba06de2a846 /servo/components/style/stylesheets/cascading_at_rule.rs | |
parent | Initial commit. (diff) | |
download | firefox-43a97878ce14b72f0981164f87f2e35e14151312.tar.xz firefox-43a97878ce14b72f0981164f87f2e35e14151312.zip |
Adding upstream version 110.0.1.upstream/110.0.1upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'servo/components/style/stylesheets/cascading_at_rule.rs')
-rw-r--r-- | servo/components/style/stylesheets/cascading_at_rule.rs | 70 |
1 files changed, 70 insertions, 0 deletions
diff --git a/servo/components/style/stylesheets/cascading_at_rule.rs b/servo/components/style/stylesheets/cascading_at_rule.rs new file mode 100644 index 0000000000..b23b0720fe --- /dev/null +++ b/servo/components/style/stylesheets/cascading_at_rule.rs @@ -0,0 +1,70 @@ +/* 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 https://mozilla.org/MPL/2.0/. */ + +//! Cascading at-rule types and traits + +use crate::stylesheets::Origin; +use std::fmt::{self, Write}; +use style_traits::{CssWriter, ToCss}; + +/// Computes the cascade precedence as according to +/// <http://dev.w3.org/csswg/css-cascade/#cascade-origin> +#[inline] +fn cascade_precendence(origin: Origin, important: bool) -> u8 { + match (origin, important) { + (Origin::UserAgent, true) => 1, + (Origin::User, true) => 2, + (Origin::Author, true) => 3, + (Origin::Author, false) => 4, + (Origin::User, false) => 5, + (Origin::UserAgent, false) => 6, + } +} + +/// Cascading rule descriptor implementation. +/// This is only used for at-rules which can cascade. These are @viewport and +/// @page, although we don't currently implement @page as such. +#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToShmem)] +pub struct DescriptorDeclaration<T> { + /// Origin of the declaration + pub origin: Origin, + /// Declaration value + pub descriptor: T, + /// Indicates the presence of a !important property. + pub important: bool, +} + +impl<T> DescriptorDeclaration<T> { + #[allow(missing_docs)] + pub fn new(origin: Origin, descriptor: T, important: bool) -> Self { + Self { + origin, + descriptor, + important, + } + } + /// Returns true iff self is equal or higher precedence to the other. + pub fn higher_or_equal_precendence(&self, other: &Self) -> bool { + let self_precedence = cascade_precendence(self.origin, self.important); + let other_precedence = cascade_precendence(other.origin, other.important); + + self_precedence <= other_precedence + } +} + +impl<T> ToCss for DescriptorDeclaration<T> +where + T: ToCss, +{ + fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result + where + W: Write, + { + self.descriptor.to_css(dest)?; + if self.important { + dest.write_str(" !important")?; + } + dest.write_char(';') + } +} |