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style: Fix style attribute important and revert-layer behavior

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By modeling it as a separate layer that behaves somewhat specially.

See https://github.com/w3c/csswg-drafts/issues/6872.

The remaining revert-layer tests that we fail are because either we
don't implement a feature (like @property) or because it's used in
keyframes (where revert is a bit unspecified and we have existing
issues with it).

Differential Revision: https://phabricator.services.mozilla.com/D133373
This commit is contained in:
Emilio Cobos Álvarez 2023-06-06 17:28:49 +02:00 • committed by Oriol Brufau
parent 5c0f044d39
commit 50510715a2
5 changed files with 67 additions and 31 deletions
Download patch file Download diff file Expand all files Collapse all files

56
components/style/applicable_declarations.rs
View file

@ -45,7 +45,9 @@ pub struct CascadePriority {
#[allow(dead_code)]
fn size_assert() {
#[allow(unsafe_code)]
unsafe { std::mem::transmute::<u32, CascadePriority>(0u32) };
unsafe {
std::mem::transmute::<u32, CascadePriority>(0u32)
};
}
impl PartialOrd for CascadePriority {
@ -57,34 +59,39 @@ impl PartialOrd for CascadePriority {
impl Ord for CascadePriority {
fn cmp(&self, other: &Self) -> std::cmp::Ordering {
self.cascade_level
.cmp(&other.cascade_level)
.then_with(|| {
let ordering = self.layer_order.cmp(&other.layer_order);
// https://drafts.csswg.org/css-cascade-5/#cascade-layering
//
// Cascade layers (like declarations) are ordered by order
// of appearance. When comparing declarations that belong to
// different layers, then for normal rules the declaration
// whose cascade layer is last wins, and for important rules
// the declaration whose cascade layer is first wins.
//
// FIXME: This creates somewhat surprising behavior for the
// style attribute, see
// https://github.com/w3c/csswg-drafts/issues/6872
if self.cascade_level.is_important() {
ordering.reverse()
} else {
ordering
}
})
self.cascade_level.cmp(&other.cascade_level).then_with(|| {
let ordering = self.layer_order.cmp(&other.layer_order);
if ordering == std::cmp::Ordering::Equal {
return ordering;
}
// https://drafts.csswg.org/css-cascade-5/#cascade-layering
//
// Cascade layers (like declarations) are ordered by order
// of appearance. When comparing declarations that belong to
// different layers, then for normal rules the declaration
// whose cascade layer is last wins, and for important rules
// the declaration whose cascade layer is first wins.
//
// But the style attribute layer for some reason is special.
if self.cascade_level.is_important() &&
!self.layer_order.is_style_attribute_layer() &&
!other.layer_order.is_style_attribute_layer()
{
ordering.reverse()
} else {
ordering
}
})
}
}
impl CascadePriority {
/// Construct a new CascadePriority for a given (level, order) pair.
pub fn new(cascade_level: CascadeLevel, layer_order: LayerOrder) -> Self {
Self { cascade_level, layer_order }
Self {
cascade_level,
layer_order,
}
}
/// Returns the layer order.
@ -149,12 +156,13 @@ impl ApplicableDeclarationBlock {
pub fn from_declarations(
declarations: Arc<Locked<PropertyDeclarationBlock>>,
level: CascadeLevel,
layer_order: LayerOrder,
) -> Self {
ApplicableDeclarationBlock {
source: StyleSource::from_declarations(declarations),
source_order: 0,
specificity: 0,
cascade_priority: CascadePriority::new(level, LayerOrder::root()),
cascade_priority: CascadePriority::new(level, layer_order),
}
}

14
components/style/gecko/wrapper.rs
View file

@ -1579,6 +1579,7 @@ impl<'le> TElement for GeckoElement<'le> {
use crate::properties::longhands::color::SpecifiedValue as SpecifiedColor;
use crate::properties::longhands::text_align::SpecifiedValue as SpecifiedTextAlign;
use crate::values::specified::color::Color;
use crate::stylesheets::layer_rule::LayerOrder;
lazy_static! {
static ref TH_RULE: ApplicableDeclarationBlock = {
let global_style_data = &*GLOBAL_STYLE_DATA;
@ -1587,7 +1588,7 @@ impl<'le> TElement for GeckoElement<'le> {
Importance::Normal,
);
let arc = Arc::new_leaked(global_style_data.shared_lock.wrap(pdb));
ApplicableDeclarationBlock::from_declarations(arc, ServoCascadeLevel::PresHints)
ApplicableDeclarationBlock::from_declarations(arc, ServoCascadeLevel::PresHints, LayerOrder::root())
};
static ref TABLE_COLOR_RULE: ApplicableDeclarationBlock = {
let global_style_data = &*GLOBAL_STYLE_DATA;
@ -1596,7 +1597,7 @@ impl<'le> TElement for GeckoElement<'le> {
Importance::Normal,
);
let arc = Arc::new_leaked(global_style_data.shared_lock.wrap(pdb));
ApplicableDeclarationBlock::from_declarations(arc, ServoCascadeLevel::PresHints)
ApplicableDeclarationBlock::from_declarations(arc, ServoCascadeLevel::PresHints, LayerOrder::root())
};
static ref MATHML_LANG_RULE: ApplicableDeclarationBlock = {
let global_style_data = &*GLOBAL_STYLE_DATA;
@ -1605,7 +1606,7 @@ impl<'le> TElement for GeckoElement<'le> {
Importance::Normal,
);
let arc = Arc::new_leaked(global_style_data.shared_lock.wrap(pdb));
ApplicableDeclarationBlock::from_declarations(arc, ServoCascadeLevel::PresHints)
ApplicableDeclarationBlock::from_declarations(arc, ServoCascadeLevel::PresHints, LayerOrder::root())
};
static ref SVG_TEXT_DISABLE_ZOOM_RULE: ApplicableDeclarationBlock = {
let global_style_data = &*GLOBAL_STYLE_DATA;
@ -1614,7 +1615,7 @@ impl<'le> TElement for GeckoElement<'le> {
Importance::Normal,
);
let arc = Arc::new_leaked(global_style_data.shared_lock.wrap(pdb));
ApplicableDeclarationBlock::from_declarations(arc, ServoCascadeLevel::PresHints)
ApplicableDeclarationBlock::from_declarations(arc, ServoCascadeLevel::PresHints, LayerOrder::root())
};
};
@ -1642,6 +1643,7 @@ impl<'le> TElement for GeckoElement<'le> {
hints.push(ApplicableDeclarationBlock::from_declarations(
decl.clone_arc(),
ServoCascadeLevel::PresHints,
LayerOrder::root(),
));
}
let declarations = unsafe { Gecko_GetExtraContentStyleDeclarations(self.0).as_ref() };
@ -1651,6 +1653,7 @@ impl<'le> TElement for GeckoElement<'le> {
hints.push(ApplicableDeclarationBlock::from_declarations(
decl.clone_arc(),
ServoCascadeLevel::PresHints,
LayerOrder::root(),
));
}
@ -1678,6 +1681,7 @@ impl<'le> TElement for GeckoElement<'le> {
hints.push(ApplicableDeclarationBlock::from_declarations(
decl.clone_arc(),
ServoCascadeLevel::PresHints,
LayerOrder::root(),
));
}
@ -1693,6 +1697,7 @@ impl<'le> TElement for GeckoElement<'le> {
hints.push(ApplicableDeclarationBlock::from_declarations(
decl.clone_arc(),
ServoCascadeLevel::PresHints,
LayerOrder::root(),
));
}
}
@ -1714,6 +1719,7 @@ impl<'le> TElement for GeckoElement<'le> {
hints.push(ApplicableDeclarationBlock::from_declarations(
arc,
ServoCascadeLevel::PresHints,
LayerOrder::root(),
))
}
// MathML's default lang has precedence over both `lang` and `xml:lang`

6
components/style/rule_collector.rs
View file

@ -11,7 +11,7 @@ use crate::rule_tree::{CascadeLevel, ShadowCascadeOrder};
use crate::selector_map::SelectorMap;
use crate::selector_parser::PseudoElement;
use crate::shared_lock::Locked;
use crate::stylesheets::Origin;
use crate::stylesheets::{layer_rule::LayerOrder, Origin};
use crate::stylist::{AuthorStylesEnabled, CascadeData, Rule, RuleInclusion, Stylist};
use selectors::matching::{ElementSelectorFlags, MatchingContext, MatchingMode};
use servo_arc::ArcBorrow;
@ -450,6 +450,7 @@ where
.push(ApplicableDeclarationBlock::from_declarations(
sa.clone_arc(),
CascadeLevel::same_tree_author_normal(),
LayerOrder::style_attribute(),
));
}
}
@ -460,6 +461,7 @@ where
.push(ApplicableDeclarationBlock::from_declarations(
so.clone_arc(),
CascadeLevel::SMILOverride,
LayerOrder::root(),
));
}
@ -471,6 +473,7 @@ where
.push(ApplicableDeclarationBlock::from_declarations(
anim,
CascadeLevel::Animations,
LayerOrder::root(),
));
}
@ -481,6 +484,7 @@ where
.push(ApplicableDeclarationBlock::from_declarations(
anim,
CascadeLevel::Transitions,
LayerOrder::root(),
));
}
}

4
components/style/rule_tree/mod.rs
View file

@ -72,7 +72,9 @@ impl RuleTree {
if any_important {
found_important = true;
match level {
AuthorNormal { .. } => important_author.push((source.clone(), priority.important())),
AuthorNormal { .. } => {
important_author.push((source.clone(), priority.important()))
},
UANormal => important_ua.push((source.clone(), priority.important())),
UserNormal => important_user.push((source.clone(), priority.important())),
_ => {},

18
components/style/stylesheets/layer_rule.rs
View file

@ -28,9 +28,25 @@ pub struct LayerOrder(u16);
impl LayerOrder {
/// The order of the root layer.
pub const fn root() -> Self {
Self(std::u16::MAX - 1)
}
/// The order of the style attribute layer.
pub const fn style_attribute() -> Self {
Self(std::u16::MAX)
}
/// Returns whether this layer is for the style attribute, which behaves
/// differently in terms of !important, see
/// https://github.com/w3c/csswg-drafts/issues/6872
///
/// (This is a bit silly, mind-you, but it's needed so that revert-layer
/// behaves correctly).
#[inline]
pub fn is_style_attribute_layer(&self) -> bool {
*self == Self::style_attribute()
}
/// The first cascade layer order.
pub const fn first() -> Self {
Self(0)
@ -39,7 +55,7 @@ impl LayerOrder {
/// Increment the cascade layer order.
#[inline]
pub fn inc(&mut self) {
if self.0 != std::u16::MAX {
if self.0 != std::u16::MAX - 1 {
self.0 += 1;
}
}