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/* 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/. */
//! Types and traits used to access the DOM from style calculation.
#![allow(unsafe_code)]
#![deny(missing_docs)]
use crate::applicable_declarations::ApplicableDeclarationBlock;
#[cfg(feature = "gecko")]
use crate::context::PostAnimationTasks;
#[cfg(feature = "gecko")]
use crate::context::UpdateAnimationsTasks;
use crate::data::ElementData;
use crate::element_state::ElementState;
use crate::font_metrics::FontMetricsProvider;
use crate::media_queries::Device;
use crate::properties::{AnimationRules, ComputedValues, PropertyDeclarationBlock};
use crate::selector_parser::{AttrValue, Lang, PseudoElement, SelectorImpl};
use crate::shared_lock::Locked;
use crate::stylist::CascadeData;
use crate::traversal_flags::TraversalFlags;
use crate::{Atom, LocalName, Namespace, WeakAtom};
use atomic_refcell::{AtomicRef, AtomicRefMut};
use selectors::matching::{ElementSelectorFlags, QuirksMode, VisitedHandlingMode};
use selectors::sink::Push;
use selectors::Element as SelectorsElement;
use servo_arc::{Arc, ArcBorrow};
use std::fmt;
use std::fmt::Debug;
use std::hash::Hash;
use std::ops::Deref;
pub use style_traits::dom::OpaqueNode;
/// Simple trait to provide basic information about the type of an element.
///
/// We avoid exposing the full type id, since computing it in the general case
/// would be difficult for Gecko nodes.
pub trait NodeInfo {
/// Whether this node is an element.
fn is_element(&self) -> bool;
/// Whether this node is a text node.
fn is_text_node(&self) -> bool;
}
/// A node iterator that only returns node that don't need layout.
pub struct LayoutIterator<T>(pub T);
impl<T, N> Iterator for LayoutIterator<T>
where
T: Iterator<Item = N>,
N: NodeInfo,
{
type Item = N;
fn next(&mut self) -> Option<N> {
loop {
let n = self.0.next()?;
// Filter out nodes that layout should ignore.
if n.is_text_node() || n.is_element() {
return Some(n);
}
}
}
}
/// An iterator over the DOM children of a node.
pub struct DomChildren<N>(Option<N>);
impl<N> Iterator for DomChildren<N>
where
N: TNode,
{
type Item = N;
fn next(&mut self) -> Option<N> {
let n = self.0.take()?;
self.0 = n.next_sibling();
Some(n)
}
}
/// An iterator over the DOM descendants of a node in pre-order.
pub struct DomDescendants<N> {
previous: Option<N>,
scope: N,
}
impl<N> Iterator for DomDescendants<N>
where
N: TNode,
{
type Item = N;
#[inline]
fn next(&mut self) -> Option<N> {
let prev = self.previous.take()?;
self.previous = prev.next_in_preorder(Some(self.scope));
self.previous
}
}
/// The `TDocument` trait, to represent a document node.
pub trait TDocument: Sized + Copy + Clone {
/// The concrete `TNode` type.
type ConcreteNode: TNode<ConcreteDocument = Self>;
/// Get this document as a `TNode`.
fn as_node(&self) -> Self::ConcreteNode;
/// Returns whether this document is an HTML document.
fn is_html_document(&self) -> bool;
/// Returns the quirks mode of this document.
fn quirks_mode(&self) -> QuirksMode;
/// Get a list of elements with a given ID in this document, sorted by
/// tree position.
///
/// Can return an error to signal that this list is not available, or also
/// return an empty slice.
fn elements_with_id<'a>(
&self,
_id: &Atom,
) -> Result<&'a [<Self::ConcreteNode as TNode>::ConcreteElement], ()>
where
Self: 'a,
{
Err(())
}
}
/// The `TNode` trait. This is the main generic trait over which the style
/// system can be implemented.
pub trait TNode: Sized + Copy + Clone + Debug + NodeInfo + PartialEq {
/// The concrete `TElement` type.
type ConcreteElement: TElement<ConcreteNode = Self>;
/// The concrete `TDocument` type.
type ConcreteDocument: TDocument<ConcreteNode = Self>;
/// The concrete `TShadowRoot` type.
type ConcreteShadowRoot: TShadowRoot<ConcreteNode = Self>;
/// Get this node's parent node.
fn parent_node(&self) -> Option<Self>;
/// Get this node's first child.
fn first_child(&self) -> Option<Self>;
/// Get this node's first child.
fn last_child(&self) -> Option<Self>;
/// Get this node's previous sibling.
fn prev_sibling(&self) -> Option<Self>;
/// Get this node's next sibling.
fn next_sibling(&self) -> Option<Self>;
/// Get the owner document of this node.
fn owner_doc(&self) -> Self::ConcreteDocument;
/// Iterate over the DOM children of a node.
fn dom_children(&self) -> DomChildren<Self> {
DomChildren(self.first_child())
}
/// Returns whether the node is attached to a document.
fn is_in_document(&self) -> bool;
/// Iterate over the DOM children of a node, in preorder.
fn dom_descendants(&self) -> DomDescendants<Self> {
DomDescendants {
previous: Some(*self),
scope: *self,
}
}
/// Returns the next children in pre-order, optionally scoped to a subtree
/// root.
#[inline]
fn next_in_preorder(&self, scoped_to: Option<Self>) -> Option<Self> {
if let Some(c) = self.first_child() {
return Some(c);
}
if Some(*self) == scoped_to {
return None;
}
let mut current = *self;
loop {
if let Some(s) = current.next_sibling() {
return Some(s);
}
let parent = current.parent_node();
if parent == scoped_to {
return None;
}
current = parent.expect("Not a descendant of the scope?");
}
}
/// Get this node's parent element from the perspective of a restyle
/// traversal.
fn traversal_parent(&self) -> Option<Self::ConcreteElement>;
/// Get this node's parent element if present.
fn parent_element(&self) -> Option<Self::ConcreteElement> {
self.parent_node().and_then(|n| n.as_element())
}
/// Converts self into an `OpaqueNode`.
fn opaque(&self) -> OpaqueNode;
/// A debug id, only useful, mm... for debugging.
fn debug_id(self) -> usize;
/// Get this node as an element, if it's one.
fn as_element(&self) -> Option<Self::ConcreteElement>;
/// Get this node as a document, if it's one.
fn as_document(&self) -> Option<Self::ConcreteDocument>;
/// Get this node as a ShadowRoot, if it's one.
fn as_shadow_root(&self) -> Option<Self::ConcreteShadowRoot>;
}
/// Wrapper to output the subtree rather than the single node when formatting
/// for Debug.
pub struct ShowSubtree<N: TNode>(pub N);
impl<N: TNode> Debug for ShowSubtree<N> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
writeln!(f, "DOM Subtree:")?;
fmt_subtree(f, &|f, n| write!(f, "{:?}", n), self.0, 1)
}
}
/// Wrapper to output the subtree along with the ElementData when formatting
/// for Debug.
pub struct ShowSubtreeData<N: TNode>(pub N);
impl<N: TNode> Debug for ShowSubtreeData<N> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
writeln!(f, "DOM Subtree:")?;
fmt_subtree(f, &|f, n| fmt_with_data(f, n), self.0, 1)
}
}
/// Wrapper to output the subtree along with the ElementData and primary
/// ComputedValues when formatting for Debug. This is extremely verbose.
#[cfg(feature = "servo")]
pub struct ShowSubtreeDataAndPrimaryValues<N: TNode>(pub N);
#[cfg(feature = "servo")]
impl<N: TNode> Debug for ShowSubtreeDataAndPrimaryValues<N> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
writeln!(f, "DOM Subtree:")?;
fmt_subtree(f, &|f, n| fmt_with_data_and_primary_values(f, n), self.0, 1)
}
}
fn fmt_with_data<N: TNode>(f: &mut fmt::Formatter, n: N) -> fmt::Result {
if let Some(el) = n.as_element() {
write!(
f,
"{:?} dd={} aodd={} data={:?}",
el,
el.has_dirty_descendants(),
el.has_animation_only_dirty_descendants(),
el.borrow_data(),
)
} else {
write!(f, "{:?}", n)
}
}
#[cfg(feature = "servo")]
fn fmt_with_data_and_primary_values<N: TNode>(f: &mut fmt::Formatter, n: N) -> fmt::Result {
if let Some(el) = n.as_element() {
let dd = el.has_dirty_descendants();
let aodd = el.has_animation_only_dirty_descendants();
let data = el.borrow_data();
let values = data.as_ref().and_then(|d| d.styles.get_primary());
write!(
f,
"{:?} dd={} aodd={} data={:?} values={:?}",
el, dd, aodd, &data, values
)
} else {
write!(f, "{:?}", n)
}
}
fn fmt_subtree<F, N: TNode>(f: &mut fmt::Formatter, stringify: &F, n: N, indent: u32) -> fmt::Result
where
F: Fn(&mut fmt::Formatter, N) -> fmt::Result,
{
for _ in 0..indent {
write!(f, " ")?;
}
stringify(f, n)?;
if let Some(e) = n.as_element() {
for kid in e.traversal_children() {
writeln!(f, "")?;
fmt_subtree(f, stringify, kid, indent + 1)?;
}
}
Ok(())
}
/// The ShadowRoot trait.
pub trait TShadowRoot: Sized + Copy + Clone + Debug + PartialEq {
/// The concrete node type.
type ConcreteNode: TNode<ConcreteShadowRoot = Self>;
/// Get this ShadowRoot as a node.
fn as_node(&self) -> Self::ConcreteNode;
/// Get the shadow host that hosts this ShadowRoot.
fn host(&self) -> <Self::ConcreteNode as TNode>::ConcreteElement;
/// Get the style data for this ShadowRoot.
fn style_data<'a>(&self) -> Option<&'a CascadeData>
where
Self: 'a;
/// Get the list of shadow parts for this shadow root.
fn parts<'a>(&self) -> &[<Self::ConcreteNode as TNode>::ConcreteElement]
where
Self: 'a,
{
&[]
}
/// Get a list of elements with a given ID in this shadow root, sorted by
/// tree position.
///
/// Can return an error to signal that this list is not available, or also
/// return an empty slice.
fn elements_with_id<'a>(
&self,
_id: &Atom,
) -> Result<&'a [<Self::ConcreteNode as TNode>::ConcreteElement], ()>
where
Self: 'a,
{
Err(())
}
}
/// The element trait, the main abstraction the style crate acts over.
pub trait TElement:
Eq + PartialEq + Debug + Hash + Sized + Copy + Clone + SelectorsElement<Impl = SelectorImpl>
{
/// The concrete node type.
type ConcreteNode: TNode<ConcreteElement = Self>;
/// A concrete children iterator type in order to iterate over the `Node`s.
///
/// TODO(emilio): We should eventually replace this with the `impl Trait`
/// syntax.
type TraversalChildrenIterator: Iterator<Item = Self::ConcreteNode>;
/// Type of the font metrics provider
///
/// XXXManishearth It would be better to make this a type parameter on
/// ThreadLocalStyleContext and StyleContext
type FontMetricsProvider: FontMetricsProvider + Send;
/// Get this element as a node.
fn as_node(&self) -> Self::ConcreteNode;
/// A debug-only check that the device's owner doc matches the actual doc
/// we're the root of.
///
/// Otherwise we may set document-level state incorrectly, like the root
/// font-size used for rem units.
fn owner_doc_matches_for_testing(&self, _: &Device) -> bool {
true
}
/// Whether this element should match user and author rules.
///
/// We use this for Native Anonymous Content in Gecko.
fn matches_user_and_author_rules(&self) -> bool {
true
}
/// Returns the depth of this element in the DOM.
fn depth(&self) -> usize {
let mut depth = 0;
let mut curr = *self;
while let Some(parent) = curr.traversal_parent() {
depth += 1;
curr = parent;
}
depth
}
/// Get this node's parent element from the perspective of a restyle
/// traversal.
fn traversal_parent(&self) -> Option<Self> {
self.as_node().traversal_parent()
}
/// Get this node's children from the perspective of a restyle traversal.
fn traversal_children(&self) -> LayoutIterator<Self::TraversalChildrenIterator>;
/// Returns the parent element we should inherit from.
///
/// This is pretty much always the parent element itself, except in the case
/// of Gecko's Native Anonymous Content, which uses the traversal parent
/// (i.e. the flattened tree parent) and which also may need to find the
/// closest non-NAC ancestor.
fn inheritance_parent(&self) -> Option<Self> {
self.parent_element()
}
/// The ::before pseudo-element of this element, if it exists.
fn before_pseudo_element(&self) -> Option<Self> {
None
}
/// The ::after pseudo-element of this element, if it exists.
fn after_pseudo_element(&self) -> Option<Self> {
None
}
/// The ::marker pseudo-element of this element, if it exists.
fn marker_pseudo_element(&self) -> Option<Self> {
None
}
/// Execute `f` for each anonymous content child (apart from ::before and
/// ::after) whose originating element is `self`.
fn each_anonymous_content_child<F>(&self, _f: F)
where
F: FnMut(Self),
{
}
/// Return whether this element is an element in the HTML namespace.
fn is_html_element(&self) -> bool;
/// Return whether this element is an element in the MathML namespace.
fn is_mathml_element(&self) -> bool;
/// Return whether this element is an element in the SVG namespace.
fn is_svg_element(&self) -> bool;
/// Return whether this element is an element in the XUL namespace.
fn is_xul_element(&self) -> bool {
false
}
/// Return the list of slotted nodes of this node.
fn slotted_nodes(&self) -> &[Self::ConcreteNode] {
&[]
}
/// Get this element's style attribute.
fn style_attribute(&self) -> Option<ArcBorrow<Locked<PropertyDeclarationBlock>>>;
/// Unset the style attribute's dirty bit.
/// Servo doesn't need to manage ditry bit for style attribute.
fn unset_dirty_style_attribute(&self) {}
/// Get this element's SMIL override declarations.
fn smil_override(&self) -> Option<ArcBorrow<Locked<PropertyDeclarationBlock>>> {
None
}
/// Get the combined animation and transition rules.
///
/// FIXME(emilio): Is this really useful?
fn animation_rules(&self) -> AnimationRules {
if !self.may_have_animations() {
return AnimationRules(None, None);
}
AnimationRules(self.animation_rule(), self.transition_rule())
}
/// Get this element's animation rule.
fn animation_rule(&self) -> Option<Arc<Locked<PropertyDeclarationBlock>>> {
None
}
/// Get this element's transition rule.
fn transition_rule(&self) -> Option<Arc<Locked<PropertyDeclarationBlock>>> {
None
}
/// Get this element's state, for non-tree-structural pseudos.
fn state(&self) -> ElementState;
/// Whether this element has an attribute with a given namespace.
fn has_attr(&self, namespace: &Namespace, attr: &LocalName) -> bool;
/// Returns whether this element has a `part` attribute.
fn has_part_attr(&self) -> bool;
/// Returns whether this element exports any part from its shadow tree.
fn exports_any_part(&self) -> bool;
/// The ID for this element.
fn id(&self) -> Option<&WeakAtom>;
/// Internal iterator for the classes of this element.
fn each_class<F>(&self, callback: F)
where
F: FnMut(&Atom);
/// Internal iterator for the part names of this element.
fn each_part<F>(&self, _callback: F)
where
F: FnMut(&Atom),
{
}
/// Internal iterator for the part names that this element exports for a
/// given part name.
fn each_exported_part<F>(&self, _name: &Atom, _callback: F)
where
F: FnMut(&Atom),
{
}
/// Whether a given element may generate a pseudo-element.
///
/// This is useful to avoid computing, for example, pseudo styles for
/// `::-first-line` or `::-first-letter`, when we know it won't affect us.
///
/// TODO(emilio, bz): actually implement the logic for it.
fn may_generate_pseudo(&self, pseudo: &PseudoElement, _primary_style: &ComputedValues) -> bool {
// ::before/::after are always supported for now, though we could try to
// optimize out leaf elements.
// ::first-letter and ::first-line are only supported for block-inside
// things, and only in Gecko, not Servo. Unfortunately, Gecko has
// block-inside things that might have any computed display value due to
// things like fieldsets, legends, etc. Need to figure out how this
// should work.
debug_assert!(
pseudo.is_eager(),
"Someone called may_generate_pseudo with a non-eager pseudo."
);
true
}
/// Returns true if this element may have a descendant needing style processing.
///
/// Note that we cannot guarantee the existence of such an element, because
/// it may have been removed from the DOM between marking it for restyle and
/// the actual restyle traversal.
fn has_dirty_descendants(&self) -> bool;
/// Returns whether state or attributes that may change style have changed
/// on the element, and thus whether the element has been snapshotted to do
/// restyle hint computation.
fn has_snapshot(&self) -> bool;
/// Returns whether the current snapshot if present has been handled.
fn handled_snapshot(&self) -> bool;
/// Flags this element as having handled already its snapshot.
unsafe fn set_handled_snapshot(&self);
/// Returns whether the element's styles are up-to-date for |traversal_flags|.
fn has_current_styles_for_traversal(
&self,
data: &ElementData,
traversal_flags: TraversalFlags,
) -> bool {
if traversal_flags.for_animation_only() {
// In animation-only restyle we never touch snapshots and don't
// care about them. But we can't assert '!self.handled_snapshot()'
// here since there are some cases that a second animation-only
// restyle which is a result of normal restyle (e.g. setting
// animation-name in normal restyle and creating a new CSS
// animation in a SequentialTask) is processed after the normal
// traversal in that we had elements that handled snapshot.
return data.has_styles() && !data.hint.has_animation_hint_or_recascade();
}
if self.has_snapshot() && !self.handled_snapshot() {
return false;
}
data.has_styles() && !data.hint.has_non_animation_invalidations()
}
/// Returns whether the element's styles are up-to-date after traversal
/// (i.e. in post traversal).
fn has_current_styles(&self, data: &ElementData) -> bool {
if self.has_snapshot() && !self.handled_snapshot() {
return false;
}
data.has_styles() &&
// TODO(hiro): When an animating element moved into subtree of
// contenteditable element, there remains animation restyle hints in
// post traversal. It's generally harmless since the hints will be
// processed in a next styling but ideally it should be processed soon.
//
// Without this, we get failures in:
// layout/style/crashtests/1383319.html
// layout/style/crashtests/1383001.html
//
// this.
!data.hint.has_non_animation_invalidations()
}
/// Flag that this element has a descendant for style processing.
///
/// Only safe to call with exclusive access to the element.
unsafe fn set_dirty_descendants(&self);
/// Flag that this element has no descendant for style processing.
///
/// Only safe to call with exclusive access to the element.
unsafe fn unset_dirty_descendants(&self);
/// Similar to the dirty_descendants but for representing a descendant of
/// the element needs to be updated in animation-only traversal.
fn has_animation_only_dirty_descendants(&self) -> bool {
false
}
/// Flag that this element has a descendant for animation-only restyle
/// processing.
///
/// Only safe to call with exclusive access to the element.
unsafe fn set_animation_only_dirty_descendants(&self) {}
/// Flag that this element has no descendant for animation-only restyle processing.
///
/// Only safe to call with exclusive access to the element.
unsafe fn unset_animation_only_dirty_descendants(&self) {}
/// Clear all bits related describing the dirtiness of descendants.
///
/// In Gecko, this corresponds to the regular dirty descendants bit, the
/// animation-only dirty descendants bit, and the lazy frame construction
/// descendants bit.
unsafe fn clear_descendant_bits(&self) {
self.unset_dirty_descendants();
}
/// Returns true if this element is a visited link.
///
/// Servo doesn't support visited styles yet.
fn is_visited_link(&self) -> bool {
false
}
/// Returns true if this element is in a native anonymous subtree.
fn is_in_native_anonymous_subtree(&self) -> bool {
false
}
/// Returns the pseudo-element implemented by this element, if any.
///
/// Gecko traverses pseudo-elements during the style traversal, and we need
/// to know this so we can properly grab the pseudo-element style from the
/// parent element.
///
/// Note that we still need to compute the pseudo-elements before-hand,
/// given otherwise we don't know if we need to create an element or not.
///
/// Servo doesn't have to deal with this.
fn implemented_pseudo_element(&self) -> Option<PseudoElement> {
None
}
/// Atomically stores the number of children of this node that we will
/// need to process during bottom-up traversal.
fn store_children_to_process(&self, n: isize);
/// Atomically notes that a child has been processed during bottom-up
/// traversal. Returns the number of children left to process.
fn did_process_child(&self) -> isize;
/// Gets a reference to the ElementData container, or creates one.
///
/// Unsafe because it can race to allocate and leak if not used with
/// exclusive access to the element.
unsafe fn ensure_data(&self) -> AtomicRefMut<ElementData>;
/// Clears the element data reference, if any.
///
/// Unsafe following the same reasoning as ensure_data.
unsafe fn clear_data(&self);
/// Whether there is an ElementData container.
fn has_data(&self) -> bool;
/// Immutably borrows the ElementData.
fn borrow_data(&self) -> Option<AtomicRef<ElementData>>;
/// Mutably borrows the ElementData.
fn mutate_data(&self) -> Option<AtomicRefMut<ElementData>>;
/// Whether we should skip any root- or item-based display property
/// blockification on this element. (This function exists so that Gecko
/// native anonymous content can opt out of this style fixup.)
fn skip_item_display_fixup(&self) -> bool;
/// Sets selector flags, which indicate what kinds of selectors may have
/// matched on this element and therefore what kind of work may need to
/// be performed when DOM state changes.
///
/// This is unsafe, like all the flag-setting methods, because it's only safe
/// to call with exclusive access to the element. When setting flags on the
/// parent during parallel traversal, we use SequentialTask to queue up the
/// set to run after the threads join.
unsafe fn set_selector_flags(&self, flags: ElementSelectorFlags);
/// Returns true if the element has all the specified selector flags.
fn has_selector_flags(&self, flags: ElementSelectorFlags) -> bool;
/// In Gecko, element has a flag that represents the element may have
/// any type of animations or not to bail out animation stuff early.
/// Whereas Servo doesn't have such flag.
fn may_have_animations(&self) -> bool {
false
}
/// Creates a task to update various animation state on a given (pseudo-)element.
#[cfg(feature = "gecko")]
fn update_animations(
&self,
before_change_style: Option<Arc<ComputedValues>>,
tasks: UpdateAnimationsTasks,
);
/// Creates a task to process post animation on a given element.
#[cfg(feature = "gecko")]
fn process_post_animation(&self, tasks: PostAnimationTasks);
/// Returns true if the element has relevant animations. Relevant
/// animations are those animations that are affecting the element's style
/// or are scheduled to do so in the future.
fn has_animations(&self) -> bool;
/// Returns true if the element has a CSS animation.
fn has_css_animations(&self) -> bool;
/// Returns true if the element has a CSS transition (including running transitions and
/// completed transitions).
fn has_css_transitions(&self) -> bool;
/// Returns true if the element has animation restyle hints.
fn has_animation_restyle_hints(&self) -> bool {
let data = match self.borrow_data() {
Some(d) => d,
None => return false,
};
return data.hint.has_animation_hint();
}
/// The shadow root this element is a host of.
fn shadow_root(&self) -> Option<<Self::ConcreteNode as TNode>::ConcreteShadowRoot>;
/// The shadow root which roots the subtree this element is contained in.
fn containing_shadow(&self) -> Option<<Self::ConcreteNode as TNode>::ConcreteShadowRoot>;
/// Return the element which we can use to look up rules in the selector
/// maps.
///
/// This is always the element itself, except in the case where we are an
/// element-backed pseudo-element, in which case we return the originating
/// element.
fn rule_hash_target(&self) -> Self {
if self.is_pseudo_element() {
self.pseudo_element_originating_element()
.expect("Trying to collect rules for a detached pseudo-element")
} else {
*self
}
}
/// Executes the callback for each applicable style rule data which isn't
/// the main document's data (which stores UA / author rules).
///
/// The element passed to the callback is the containing shadow host for the
/// data if it comes from Shadow DOM.
///
/// Returns whether normal document author rules should apply.
///
/// TODO(emilio): We could separate the invalidation data for elements
/// matching in other scopes to avoid over-invalidation.
fn each_applicable_non_document_style_rule_data<'a, F>(&self, mut f: F) -> bool
where
Self: 'a,
F: FnMut(&'a CascadeData, Self),
{
use rule_collector::containing_shadow_ignoring_svg_use;
let target = self.rule_hash_target();
if !target.matches_user_and_author_rules() {
return false;
}
let mut doc_rules_apply = true;
// Use the same rules to look for the containing host as we do for rule
// collection.
if let Some(shadow) = containing_shadow_ignoring_svg_use(target) {
doc_rules_apply = false;
if let Some(data) = shadow.style_data() {
f(data, shadow.host());
}
}
if let Some(shadow) = target.shadow_root() {
if let Some(data) = shadow.style_data() {
f(data, shadow.host());
}
}
let mut current = target.assigned_slot();
while let Some(slot) = current {
// Slots can only have assigned nodes when in a shadow tree.
let shadow = slot.containing_shadow().unwrap();
if let Some(data) = shadow.style_data() {
if data.any_slotted_rule() {
f(data, shadow.host());
}
}
current = slot.assigned_slot();
}
if target.has_part_attr() {
if let Some(mut inner_shadow) = target.containing_shadow() {
loop {
let inner_shadow_host = inner_shadow.host();
match inner_shadow_host.containing_shadow() {
Some(shadow) => {
if let Some(data) = shadow.style_data() {
if data.any_part_rule() {
f(data, shadow.host())
}
}
// TODO: Could be more granular.
if !shadow.host().exports_any_part() {
break;
}
inner_shadow = shadow;
},
None => {
// TODO(emilio): Should probably distinguish with
// MatchesDocumentRules::{No,Yes,IfPart} or
// something so that we could skip some work.
doc_rules_apply = true;
break;
},
}
}
}
}
doc_rules_apply
}
/// Does a rough (and cheap) check for whether or not transitions might need to be updated that
/// will quickly return false for the common case of no transitions specified or running. If
/// this returns false, we definitely don't need to update transitions but if it returns true
/// we can perform the more thoroughgoing check, needs_transitions_update, to further
/// reduce the possibility of false positives.
#[cfg(feature = "gecko")]
fn might_need_transitions_update(
&self,
old_values: Option<&ComputedValues>,
new_values: &ComputedValues,
) -> bool;
/// Returns true if one of the transitions needs to be updated on this element. We check all
/// the transition properties to make sure that updating transitions is necessary.
/// This method should only be called if might_needs_transitions_update returns true when
/// passed the same parameters.
#[cfg(feature = "gecko")]
fn needs_transitions_update(
&self,
before_change_style: &ComputedValues,
after_change_style: &ComputedValues,
) -> bool;
/// Returns the value of the `xml:lang=""` attribute (or, if appropriate,
/// the `lang=""` attribute) on this element.
fn lang_attr(&self) -> Option<AttrValue>;
/// Returns whether this element's language matches the language tag
/// `value`. If `override_lang` is not `None`, it specifies the value
/// of the `xml:lang=""` or `lang=""` attribute to use in place of
/// looking at the element and its ancestors. (This argument is used
/// to implement matching of `:lang()` against snapshots.)
fn match_element_lang(&self, override_lang: Option<Option<AttrValue>>, value: &Lang) -> bool;
/// Returns whether this element is the main body element of the HTML
/// document it is on.
fn is_html_document_body_element(&self) -> bool;
/// Generate the proper applicable declarations due to presentational hints,
/// and insert them into `hints`.
fn synthesize_presentational_hints_for_legacy_attributes<V>(
&self,
visited_handling: VisitedHandlingMode,
hints: &mut V,
) where
V: Push<ApplicableDeclarationBlock>;
/// Returns element's local name.
fn local_name(&self) -> &<SelectorImpl as selectors::parser::SelectorImpl>::BorrowedLocalName;
/// Returns element's namespace.
fn namespace(&self)
-> &<SelectorImpl as selectors::parser::SelectorImpl>::BorrowedNamespaceUrl;
}
/// TNode and TElement aren't Send because we want to be careful and explicit
/// about our parallel traversal. However, there are certain situations
/// (including but not limited to the traversal) where we need to send DOM
/// objects to other threads.
///
/// That's the reason why `SendNode` exists.
#[derive(Clone, Debug, PartialEq)]
pub struct SendNode<N: TNode>(N);
unsafe impl<N: TNode> Send for SendNode<N> {}
impl<N: TNode> SendNode<N> {
/// Unsafely construct a SendNode.
pub unsafe fn new(node: N) -> Self {
SendNode(node)
}
}
impl<N: TNode> Deref for SendNode<N> {
type Target = N;
fn deref(&self) -> &N {
&self.0
}
}
/// Same reason as for the existence of SendNode, SendElement does the proper
/// things for a given `TElement`.
#[derive(Debug, Eq, Hash, PartialEq)]
pub struct SendElement<E: TElement>(E);
unsafe impl<E: TElement> Send for SendElement<E> {}
impl<E: TElement> SendElement<E> {
/// Unsafely construct a SendElement.
pub unsafe fn new(el: E) -> Self {
SendElement(el)
}
}
impl<E: TElement> Deref for SendElement<E> {
type Target = E;
fn deref(&self) -> &E {
&self.0
}
}