servo/components/style/matching.rs
Emilio Cobos Álvarez 76847f7b45 style: Move transitions and animations to nsStyleUIReset
This mostly just moves code around, to minimize potential behavior
changes. There are some cleanups that we should try to do long term
(this "have an array with n different counts" is pretty weird).

But for now this should unblock people.

The destination struct (nsStyleUIReset) was chosen mainly because it's
small and non-inherited, and it doesn't seem like a worse place than
nsStyleDisplay.

Differential Revision: https://phabricator.services.mozilla.com/D144183
2023-08-16 17:46:41 +02:00

1048 lines
38 KiB
Rust

/* 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/. */
//! High-level interface to CSS selector matching.
#![allow(unsafe_code)]
#![deny(missing_docs)]
use crate::computed_value_flags::ComputedValueFlags;
use crate::context::{CascadeInputs, ElementCascadeInputs, QuirksMode};
use crate::context::{SharedStyleContext, StyleContext};
use crate::data::{ElementData, ElementStyles};
use crate::dom::TElement;
#[cfg(feature = "servo")]
use crate::dom::TNode;
use crate::invalidation::element::restyle_hints::RestyleHint;
use crate::properties::longhands::display::computed_value::T as Display;
use crate::properties::ComputedValues;
use crate::properties::PropertyDeclarationBlock;
use crate::rule_tree::{CascadeLevel, StrongRuleNode};
use crate::selector_parser::{PseudoElement, RestyleDamage};
use crate::shared_lock::Locked;
use crate::style_resolver::ResolvedElementStyles;
use crate::style_resolver::{PseudoElementResolution, StyleResolverForElement};
use crate::stylesheets::layer_rule::LayerOrder;
use crate::stylist::RuleInclusion;
use crate::traversal_flags::TraversalFlags;
use servo_arc::{Arc, ArcBorrow};
/// Represents the result of comparing an element's old and new style.
#[derive(Debug)]
pub struct StyleDifference {
/// The resulting damage.
pub damage: RestyleDamage,
/// Whether any styles changed.
pub change: StyleChange,
}
/// Represents whether or not the style of an element has changed.
#[derive(Clone, Copy, Debug)]
pub enum StyleChange {
/// The style hasn't changed.
Unchanged,
/// The style has changed.
Changed {
/// Whether only reset structs changed.
reset_only: bool,
},
}
/// Whether or not newly computed values for an element need to be cascade
/// to children.
#[derive(Clone, Copy, Debug, Eq, Ord, PartialEq, PartialOrd)]
pub enum ChildCascadeRequirement {
/// Old and new computed values were the same, or we otherwise know that
/// we won't bother recomputing style for children, so we can skip cascading
/// the new values into child elements.
CanSkipCascade = 0,
/// The same as `MustCascadeChildren`, but we only need to actually
/// recascade if the child inherits any explicit reset style.
MustCascadeChildrenIfInheritResetStyle = 1,
/// Old and new computed values were different, so we must cascade the
/// new values to children.
MustCascadeChildren = 2,
/// The same as `MustCascadeChildren`, but for the entire subtree. This is
/// used to handle root font-size updates needing to recascade the whole
/// document.
MustCascadeDescendants = 3,
}
impl ChildCascadeRequirement {
/// Whether we can unconditionally skip the cascade.
pub fn can_skip_cascade(&self) -> bool {
matches!(*self, ChildCascadeRequirement::CanSkipCascade)
}
}
/// Determines which styles are being cascaded currently.
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
enum CascadeVisitedMode {
/// Cascade the regular, unvisited styles.
Unvisited,
/// Cascade the styles used when an element's relevant link is visited. A
/// "relevant link" is the element being matched if it is a link or the
/// nearest ancestor link.
Visited,
}
trait PrivateMatchMethods: TElement {
fn replace_single_rule_node(
context: &SharedStyleContext,
level: CascadeLevel,
layer_order: LayerOrder,
pdb: Option<ArcBorrow<Locked<PropertyDeclarationBlock>>>,
path: &mut StrongRuleNode,
) -> bool {
let stylist = &context.stylist;
let guards = &context.guards;
let mut important_rules_changed = false;
let new_node = stylist.rule_tree().update_rule_at_level(
level,
layer_order,
pdb,
path,
guards,
&mut important_rules_changed,
);
if let Some(n) = new_node {
*path = n;
}
important_rules_changed
}
/// Updates the rule nodes without re-running selector matching, using just
/// the rule tree, for a specific visited mode.
///
/// Returns true if an !important rule was replaced.
fn replace_rules_internal(
&self,
replacements: RestyleHint,
context: &mut StyleContext<Self>,
cascade_visited: CascadeVisitedMode,
cascade_inputs: &mut ElementCascadeInputs,
) -> bool {
debug_assert!(
replacements.intersects(RestyleHint::replacements()) &&
(replacements & !RestyleHint::replacements()).is_empty()
);
let primary_rules = match cascade_visited {
CascadeVisitedMode::Unvisited => cascade_inputs.primary.rules.as_mut(),
CascadeVisitedMode::Visited => cascade_inputs.primary.visited_rules.as_mut(),
};
let primary_rules = match primary_rules {
Some(r) => r,
None => return false,
};
if !context.shared.traversal_flags.for_animation_only() {
let mut result = false;
if replacements.contains(RestyleHint::RESTYLE_STYLE_ATTRIBUTE) {
let style_attribute = self.style_attribute();
result |= Self::replace_single_rule_node(
context.shared,
CascadeLevel::same_tree_author_normal(),
LayerOrder::root(),
style_attribute,
primary_rules,
);
result |= Self::replace_single_rule_node(
context.shared,
CascadeLevel::same_tree_author_important(),
LayerOrder::root(),
style_attribute,
primary_rules,
);
// FIXME(emilio): Still a hack!
self.unset_dirty_style_attribute();
}
return result;
}
// Animation restyle hints are processed prior to other restyle
// hints in the animation-only traversal.
//
// Non-animation restyle hints will be processed in a subsequent
// normal traversal.
if replacements.intersects(RestyleHint::for_animations()) {
debug_assert!(context.shared.traversal_flags.for_animation_only());
if replacements.contains(RestyleHint::RESTYLE_SMIL) {
Self::replace_single_rule_node(
context.shared,
CascadeLevel::SMILOverride,
LayerOrder::root(),
self.smil_override(),
primary_rules,
);
}
if replacements.contains(RestyleHint::RESTYLE_CSS_TRANSITIONS) {
Self::replace_single_rule_node(
context.shared,
CascadeLevel::Transitions,
LayerOrder::root(),
self.transition_rule(&context.shared)
.as_ref()
.map(|a| a.borrow_arc()),
primary_rules,
);
}
if replacements.contains(RestyleHint::RESTYLE_CSS_ANIMATIONS) {
Self::replace_single_rule_node(
context.shared,
CascadeLevel::Animations,
LayerOrder::root(),
self.animation_rule(&context.shared)
.as_ref()
.map(|a| a.borrow_arc()),
primary_rules,
);
}
}
false
}
/// If there is no transition rule in the ComputedValues, it returns None.
fn after_change_style(
&self,
context: &mut StyleContext<Self>,
primary_style: &Arc<ComputedValues>,
) -> Option<Arc<ComputedValues>> {
let rule_node = primary_style.rules();
let without_transition_rules = context
.shared
.stylist
.rule_tree()
.remove_transition_rule_if_applicable(rule_node);
if without_transition_rules == *rule_node {
// We don't have transition rule in this case, so return None to let
// the caller use the original ComputedValues.
return None;
}
// FIXME(bug 868975): We probably need to transition visited style as
// well.
let inputs = CascadeInputs {
rules: Some(without_transition_rules),
visited_rules: primary_style.visited_rules().cloned(),
};
// Actually `PseudoElementResolution` doesn't really matter.
let style = StyleResolverForElement::new(
*self,
context,
RuleInclusion::All,
PseudoElementResolution::IfApplicable,
)
.cascade_style_and_visited_with_default_parents(inputs);
Some(style.0)
}
fn needs_animations_update(
&self,
context: &mut StyleContext<Self>,
old_style: Option<&ComputedValues>,
new_style: &ComputedValues,
pseudo_element: Option<PseudoElement>,
) -> bool {
let new_ui_style = new_style.get_ui();
let new_style_specifies_animations = new_ui_style.specifies_animations();
let has_animations = self.has_css_animations(&context.shared, pseudo_element);
if !new_style_specifies_animations && !has_animations {
return false;
}
let old_style = match old_style {
Some(old) => old,
// If we have no old style but have animations, we may be a
// pseudo-element which was re-created without style changes.
//
// This can happen when we reframe the pseudo-element without
// restyling it (due to content insertion on a flex container or
// such, for example). See bug 1564366.
//
// FIXME(emilio): The really right fix for this is keeping the
// pseudo-element itself around on reframes, but that's a bit
// harder. If we do that we can probably remove quite a lot of the
// EffectSet complexity though, since right now it's stored on the
// parent element for pseudo-elements given we need to keep it
// around...
None => {
return new_style_specifies_animations || new_style.is_pseudo_style();
},
};
let old_ui_style = old_style.get_ui();
let keyframes_or_timeline_could_have_changed = context
.shared
.traversal_flags
.contains(TraversalFlags::ForCSSRuleChanges);
// If the traversal is triggered due to changes in CSS rules changes, we
// need to try to update all CSS animations on the element if the
// element has or will have CSS animation style regardless of whether
// the animation is running or not.
//
// TODO: We should check which @keyframes/@scroll-timeline were added/changed/deleted and
// update only animations corresponding to those @keyframes/@scroll-timeline.
if keyframes_or_timeline_could_have_changed {
return true;
}
// If the animations changed, well...
if !old_ui_style.animations_equals(new_ui_style) {
return true;
}
let old_display = old_style.clone_display();
let new_display = new_style.clone_display();
// If we were display: none, we may need to trigger animations.
if old_display == Display::None && new_display != Display::None {
return new_style_specifies_animations;
}
// If we are becoming display: none, we may need to stop animations.
if old_display != Display::None && new_display == Display::None {
return has_animations;
}
// We might need to update animations if writing-mode or direction
// changed, and any of the animations contained logical properties.
//
// We may want to be more granular, but it's probably not worth it.
if new_style.writing_mode != old_style.writing_mode {
return has_animations;
}
false
}
fn might_need_transitions_update(
&self,
context: &StyleContext<Self>,
old_style: Option<&ComputedValues>,
new_style: &ComputedValues,
pseudo_element: Option<PseudoElement>,
) -> bool {
let old_style = match old_style {
Some(v) => v,
None => return false,
};
if !self.has_css_transitions(context.shared, pseudo_element) &&
!new_style.get_ui().specifies_transitions()
{
return false;
}
if new_style.clone_display().is_none() || old_style.clone_display().is_none() {
return false;
}
return true;
}
/// Create a SequentialTask for resolving descendants in a SMIL display
/// property animation if the display property changed from none.
#[cfg(feature = "gecko")]
fn handle_display_change_for_smil_if_needed(
&self,
context: &mut StyleContext<Self>,
old_values: Option<&ComputedValues>,
new_values: &ComputedValues,
restyle_hints: RestyleHint,
) {
use crate::context::PostAnimationTasks;
if !restyle_hints.intersects(RestyleHint::RESTYLE_SMIL) {
return;
}
if new_values.is_display_property_changed_from_none(old_values) {
// When display value is changed from none to other, we need to
// traverse descendant elements in a subsequent normal
// traversal (we can't traverse them in this animation-only restyle
// since we have no way to know whether the decendants
// need to be traversed at the beginning of the animation-only
// restyle).
let task = crate::context::SequentialTask::process_post_animation(
*self,
PostAnimationTasks::DISPLAY_CHANGED_FROM_NONE_FOR_SMIL,
);
context.thread_local.tasks.push(task);
}
}
#[cfg(feature = "gecko")]
fn process_animations(
&self,
context: &mut StyleContext<Self>,
old_styles: &mut ElementStyles,
new_styles: &mut ResolvedElementStyles,
restyle_hint: RestyleHint,
important_rules_changed: bool,
) {
use crate::context::UpdateAnimationsTasks;
let new_values = new_styles.primary_style_mut();
let old_values = &old_styles.primary;
if context.shared.traversal_flags.for_animation_only() {
self.handle_display_change_for_smil_if_needed(
context,
old_values.as_deref(),
new_values,
restyle_hint,
);
return;
}
// Bug 868975: These steps should examine and update the visited styles
// in addition to the unvisited styles.
let mut tasks = UpdateAnimationsTasks::empty();
if self.needs_animations_update(
context,
old_values.as_deref(),
new_values,
/* pseudo_element = */ None,
) {
tasks.insert(UpdateAnimationsTasks::CSS_ANIMATIONS);
}
let before_change_style = if self.might_need_transitions_update(
context,
old_values.as_deref(),
new_values,
/* pseudo_element = */ None,
) {
let after_change_style =
if self.has_css_transitions(context.shared, /* pseudo_element = */ None) {
self.after_change_style(context, new_values)
} else {
None
};
// In order to avoid creating a SequentialTask for transitions which
// may not be updated, we check it per property to make sure Gecko
// side will really update transition.
let needs_transitions_update = {
// We borrow new_values here, so need to add a scope to make
// sure we release it before assigning a new value to it.
let after_change_style_ref = after_change_style.as_ref().unwrap_or(&new_values);
self.needs_transitions_update(old_values.as_ref().unwrap(), after_change_style_ref)
};
if needs_transitions_update {
if let Some(values_without_transitions) = after_change_style {
*new_values = values_without_transitions;
}
tasks.insert(UpdateAnimationsTasks::CSS_TRANSITIONS);
// We need to clone old_values into SequentialTask, so we can
// use it later.
old_values.clone()
} else {
None
}
} else {
None
};
if self.has_animations(&context.shared) {
tasks.insert(UpdateAnimationsTasks::EFFECT_PROPERTIES);
if important_rules_changed {
tasks.insert(UpdateAnimationsTasks::CASCADE_RESULTS);
}
if new_values.is_display_property_changed_from_none(old_values.as_deref()) {
tasks.insert(UpdateAnimationsTasks::DISPLAY_CHANGED_FROM_NONE);
}
}
if !tasks.is_empty() {
let task = crate::context::SequentialTask::update_animations(
*self,
before_change_style,
tasks,
);
context.thread_local.tasks.push(task);
}
}
#[cfg(feature = "servo")]
fn process_animations(
&self,
context: &mut StyleContext<Self>,
old_styles: &mut ElementStyles,
new_resolved_styles: &mut ResolvedElementStyles,
_restyle_hint: RestyleHint,
_important_rules_changed: bool,
) {
use crate::animation::AnimationSetKey;
use crate::dom::TDocument;
let style_changed = self.process_animations_for_style(
context,
&mut old_styles.primary,
new_resolved_styles.primary_style_mut(),
/* pseudo_element = */ None,
);
// If we have modified animation or transitions, we recascade style for this node.
if style_changed {
let mut rule_node = new_resolved_styles.primary_style().rules().clone();
let declarations = context.shared.animations.get_all_declarations(
&AnimationSetKey::new_for_non_pseudo(self.as_node().opaque()),
context.shared.current_time_for_animations,
self.as_node().owner_doc().shared_lock(),
);
Self::replace_single_rule_node(
&context.shared,
CascadeLevel::Transitions,
LayerOrder::root(),
declarations.transitions.as_ref().map(|a| a.borrow_arc()),
&mut rule_node,
);
Self::replace_single_rule_node(
&context.shared,
CascadeLevel::Animations,
LayerOrder::root(),
declarations.animations.as_ref().map(|a| a.borrow_arc()),
&mut rule_node,
);
if rule_node != *new_resolved_styles.primary_style().rules() {
let inputs = CascadeInputs {
rules: Some(rule_node),
visited_rules: new_resolved_styles.primary_style().visited_rules().cloned(),
};
new_resolved_styles.primary.style = StyleResolverForElement::new(
*self,
context,
RuleInclusion::All,
PseudoElementResolution::IfApplicable,
)
.cascade_style_and_visited_with_default_parents(inputs);
}
}
self.process_animations_for_pseudo(
context,
old_styles,
new_resolved_styles,
PseudoElement::Before,
);
self.process_animations_for_pseudo(
context,
old_styles,
new_resolved_styles,
PseudoElement::After,
);
}
#[cfg(feature = "servo")]
fn process_animations_for_pseudo(
&self,
context: &mut StyleContext<Self>,
old_styles: &mut ElementStyles,
new_resolved_styles: &mut ResolvedElementStyles,
pseudo_element: PseudoElement,
) {
use crate::animation::AnimationSetKey;
use crate::dom::TDocument;
let key = AnimationSetKey::new_for_pseudo(self.as_node().opaque(), pseudo_element.clone());
let mut style = match new_resolved_styles.pseudos.get(&pseudo_element) {
Some(style) => Arc::clone(style),
None => {
context
.shared
.animations
.cancel_all_animations_for_key(&key);
return;
},
};
let mut old_style = old_styles.pseudos.get(&pseudo_element).cloned();
self.process_animations_for_style(
context,
&mut old_style,
&mut style,
Some(pseudo_element.clone()),
);
let declarations = context.shared.animations.get_all_declarations(
&key,
context.shared.current_time_for_animations,
self.as_node().owner_doc().shared_lock(),
);
if declarations.is_empty() {
return;
}
let mut rule_node = style.rules().clone();
Self::replace_single_rule_node(
&context.shared,
CascadeLevel::Transitions,
LayerOrder::root(),
declarations.transitions.as_ref().map(|a| a.borrow_arc()),
&mut rule_node,
);
Self::replace_single_rule_node(
&context.shared,
CascadeLevel::Animations,
LayerOrder::root(),
declarations.animations.as_ref().map(|a| a.borrow_arc()),
&mut rule_node,
);
if rule_node == *style.rules() {
return;
}
let inputs = CascadeInputs {
rules: Some(rule_node),
visited_rules: style.visited_rules().cloned(),
};
let new_style = StyleResolverForElement::new(
*self,
context,
RuleInclusion::All,
PseudoElementResolution::IfApplicable,
)
.cascade_style_and_visited_for_pseudo_with_default_parents(
inputs,
&pseudo_element,
&new_resolved_styles.primary,
);
new_resolved_styles
.pseudos
.set(&pseudo_element, new_style.0);
}
#[cfg(feature = "servo")]
fn process_animations_for_style(
&self,
context: &mut StyleContext<Self>,
old_values: &mut Option<Arc<ComputedValues>>,
new_values: &mut Arc<ComputedValues>,
pseudo_element: Option<PseudoElement>,
) -> bool {
use crate::animation::{AnimationSetKey, AnimationState};
// We need to call this before accessing the `ElementAnimationSet` from the
// map because this call will do a RwLock::read().
let needs_animations_update = self.needs_animations_update(
context,
old_values.as_deref(),
new_values,
pseudo_element,
);
let might_need_transitions_update = self.might_need_transitions_update(
context,
old_values.as_deref(),
new_values,
pseudo_element,
);
let mut after_change_style = None;
if might_need_transitions_update {
after_change_style = self.after_change_style(context, new_values);
}
let key = AnimationSetKey::new(self.as_node().opaque(), pseudo_element);
let shared_context = context.shared;
let mut animation_set = shared_context
.animations
.sets
.write()
.remove(&key)
.unwrap_or_default();
// Starting animations is expensive, because we have to recalculate the style
// for all the keyframes. We only want to do this if we think that there's a
// chance that the animations really changed.
if needs_animations_update {
let mut resolver = StyleResolverForElement::new(
*self,
context,
RuleInclusion::All,
PseudoElementResolution::IfApplicable,
);
animation_set.update_animations_for_new_style::<Self>(
*self,
&shared_context,
&new_values,
&mut resolver,
);
}
animation_set.update_transitions_for_new_style(
might_need_transitions_update,
&shared_context,
old_values.as_ref(),
after_change_style.as_ref().unwrap_or(new_values),
);
// We clear away any finished transitions, but retain animations, because they
// might still be used for proper calculation of `animation-fill-mode`. This
// should change the computed values in the style, so we don't need to mark
// this set as dirty.
animation_set
.transitions
.retain(|transition| transition.state != AnimationState::Finished);
// If the ElementAnimationSet is empty, and don't store it in order to
// save memory and to avoid extra processing later.
let changed_animations = animation_set.dirty;
if !animation_set.is_empty() {
animation_set.dirty = false;
shared_context
.animations
.sets
.write()
.insert(key, animation_set);
}
changed_animations
}
/// Computes and applies non-redundant damage.
fn accumulate_damage_for(
&self,
shared_context: &SharedStyleContext,
damage: &mut RestyleDamage,
old_values: &ComputedValues,
new_values: &ComputedValues,
pseudo: Option<&PseudoElement>,
) -> ChildCascadeRequirement {
debug!("accumulate_damage_for: {:?}", self);
debug_assert!(!shared_context
.traversal_flags
.contains(TraversalFlags::FinalAnimationTraversal));
let difference = self.compute_style_difference(old_values, new_values, pseudo);
*damage |= difference.damage;
debug!(" > style difference: {:?}", difference);
// We need to cascade the children in order to ensure the correct
// propagation of inherited computed value flags.
if old_values.flags.maybe_inherited() != new_values.flags.maybe_inherited() {
debug!(
" > flags changed: {:?} != {:?}",
old_values.flags, new_values.flags
);
return ChildCascadeRequirement::MustCascadeChildren;
}
match difference.change {
StyleChange::Unchanged => return ChildCascadeRequirement::CanSkipCascade,
StyleChange::Changed { reset_only } => {
// If inherited properties changed, the best we can do is
// cascade the children.
if !reset_only {
return ChildCascadeRequirement::MustCascadeChildren;
}
},
}
let old_display = old_values.clone_display();
let new_display = new_values.clone_display();
if old_display != new_display {
// If we used to be a display: none element, and no longer are, our
// children need to be restyled because they're unstyled.
if old_display == Display::None {
return ChildCascadeRequirement::MustCascadeChildren;
}
// Blockification of children may depend on our display value,
// so we need to actually do the recascade. We could potentially
// do better, but it doesn't seem worth it.
if old_display.is_item_container() != new_display.is_item_container() {
return ChildCascadeRequirement::MustCascadeChildren;
}
// We may also need to blockify and un-blockify descendants if our
// display goes from / to display: contents, since the "layout
// parent style" changes.
if old_display.is_contents() || new_display.is_contents() {
return ChildCascadeRequirement::MustCascadeChildren;
}
// Line break suppression may also be affected if the display
// type changes from ruby to non-ruby.
#[cfg(feature = "gecko")]
{
if old_display.is_ruby_type() != new_display.is_ruby_type() {
return ChildCascadeRequirement::MustCascadeChildren;
}
}
}
// Children with justify-items: auto may depend on our
// justify-items property value.
//
// Similarly, we could potentially do better, but this really
// seems not common enough to care about.
#[cfg(feature = "gecko")]
{
use crate::values::specified::align::AlignFlags;
let old_justify_items = old_values.get_position().clone_justify_items();
let new_justify_items = new_values.get_position().clone_justify_items();
let was_legacy_justify_items =
old_justify_items.computed.0.contains(AlignFlags::LEGACY);
let is_legacy_justify_items = new_justify_items.computed.0.contains(AlignFlags::LEGACY);
if is_legacy_justify_items != was_legacy_justify_items {
return ChildCascadeRequirement::MustCascadeChildren;
}
if was_legacy_justify_items && old_justify_items.computed != new_justify_items.computed
{
return ChildCascadeRequirement::MustCascadeChildren;
}
}
#[cfg(feature = "servo")]
{
// We may need to set or propagate the CAN_BE_FRAGMENTED bit
// on our children.
if old_values.is_multicol() != new_values.is_multicol() {
return ChildCascadeRequirement::MustCascadeChildren;
}
}
// We could prove that, if our children don't inherit reset
// properties, we can stop the cascade.
ChildCascadeRequirement::MustCascadeChildrenIfInheritResetStyle
}
}
impl<E: TElement> PrivateMatchMethods for E {}
/// The public API that elements expose for selector matching.
pub trait MatchMethods: TElement {
/// Returns the closest parent element that doesn't have a display: contents
/// style (and thus generates a box).
///
/// This is needed to correctly handle blockification of flex and grid
/// items.
///
/// Returns itself if the element has no parent. In practice this doesn't
/// happen because the root element is blockified per spec, but it could
/// happen if we decide to not blockify for roots of disconnected subtrees,
/// which is a kind of dubious behavior.
fn layout_parent(&self) -> Self {
let mut current = self.clone();
loop {
current = match current.traversal_parent() {
Some(el) => el,
None => return current,
};
let is_display_contents = current
.borrow_data()
.unwrap()
.styles
.primary()
.is_display_contents();
if !is_display_contents {
return current;
}
}
}
/// Updates the styles with the new ones, diffs them, and stores the restyle
/// damage.
fn finish_restyle(
&self,
context: &mut StyleContext<Self>,
data: &mut ElementData,
mut new_styles: ResolvedElementStyles,
important_rules_changed: bool,
) -> ChildCascadeRequirement {
use std::cmp;
self.process_animations(
context,
&mut data.styles,
&mut new_styles,
data.hint,
important_rules_changed,
);
// First of all, update the styles.
let old_styles = data.set_styles(new_styles);
let new_primary_style = data.styles.primary.as_ref().unwrap();
let mut cascade_requirement = ChildCascadeRequirement::CanSkipCascade;
if new_primary_style
.flags
.contains(ComputedValueFlags::IS_ROOT_ELEMENT_STYLE)
{
let device = context.shared.stylist.device();
let new_font_size = new_primary_style.get_font().clone_font_size();
if old_styles
.primary
.as_ref()
.map_or(true, |s| s.get_font().clone_font_size() != new_font_size)
{
debug_assert!(self.owner_doc_matches_for_testing(device));
device.set_root_font_size(new_font_size.size().into());
// If the root font-size changed since last time, and something
// in the document did use rem units, ensure we recascade the
// entire tree.
if device.used_root_font_size() {
cascade_requirement = ChildCascadeRequirement::MustCascadeDescendants;
}
}
}
if context.shared.stylist.quirks_mode() == QuirksMode::Quirks {
if self.is_html_document_body_element() {
// NOTE(emilio): We _could_ handle dynamic changes to it if it
// changes and before we reach our children the cascade stops,
// but we don't track right now whether we use the document body
// color, and nobody else handles that properly anyway.
let device = context.shared.stylist.device();
// Needed for the "inherit from body" quirk.
let text_color = new_primary_style.get_inherited_text().clone_color();
device.set_body_text_color(text_color);
}
}
// Don't accumulate damage if we're in the final animation traversal.
if context
.shared
.traversal_flags
.contains(TraversalFlags::FinalAnimationTraversal)
{
return ChildCascadeRequirement::MustCascadeChildren;
}
// Also, don't do anything if there was no style.
let old_primary_style = match old_styles.primary {
Some(s) => s,
None => return ChildCascadeRequirement::MustCascadeChildren,
};
cascade_requirement = cmp::max(
cascade_requirement,
self.accumulate_damage_for(
context.shared,
&mut data.damage,
&old_primary_style,
new_primary_style,
None,
),
);
if data.styles.pseudos.is_empty() && old_styles.pseudos.is_empty() {
// This is the common case; no need to examine pseudos here.
return cascade_requirement;
}
let pseudo_styles = old_styles
.pseudos
.as_array()
.iter()
.zip(data.styles.pseudos.as_array().iter());
for (i, (old, new)) in pseudo_styles.enumerate() {
match (old, new) {
(&Some(ref old), &Some(ref new)) => {
self.accumulate_damage_for(
context.shared,
&mut data.damage,
old,
new,
Some(&PseudoElement::from_eager_index(i)),
);
},
(&None, &None) => {},
_ => {
// It's possible that we're switching from not having
// ::before/::after at all to having styles for them but not
// actually having a useful pseudo-element. Check for that
// case.
let pseudo = PseudoElement::from_eager_index(i);
let new_pseudo_should_exist =
new.as_ref().map_or(false, |s| pseudo.should_exist(s));
let old_pseudo_should_exist =
old.as_ref().map_or(false, |s| pseudo.should_exist(s));
if new_pseudo_should_exist != old_pseudo_should_exist {
data.damage |= RestyleDamage::reconstruct();
return cascade_requirement;
}
},
}
}
cascade_requirement
}
/// Updates the rule nodes without re-running selector matching, using just
/// the rule tree.
///
/// Returns true if an !important rule was replaced.
fn replace_rules(
&self,
replacements: RestyleHint,
context: &mut StyleContext<Self>,
cascade_inputs: &mut ElementCascadeInputs,
) -> bool {
let mut result = false;
result |= self.replace_rules_internal(
replacements,
context,
CascadeVisitedMode::Unvisited,
cascade_inputs,
);
result |= self.replace_rules_internal(
replacements,
context,
CascadeVisitedMode::Visited,
cascade_inputs,
);
result
}
/// Given the old and new style of this element, and whether it's a
/// pseudo-element, compute the restyle damage used to determine which
/// kind of layout or painting operations we'll need.
fn compute_style_difference(
&self,
old_values: &ComputedValues,
new_values: &ComputedValues,
pseudo: Option<&PseudoElement>,
) -> StyleDifference {
debug_assert!(pseudo.map_or(true, |p| p.is_eager()));
RestyleDamage::compute_style_difference(old_values, new_values)
}
}
impl<E: TElement> MatchMethods for E {}