gecko-dev/servo/components/selectors/matching.rs

862 строки
29 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 http://mozilla.org/MPL/2.0/. */
use attr::{ParsedAttrSelectorOperation, AttrSelectorOperation, NamespaceConstraint};
use bloom::{BLOOM_HASH_MASK, BloomFilter};
use nth_index_cache::NthIndexCacheInner;
use parser::{AncestorHashes, Combinator, Component, LocalName};
use parser::{Selector, SelectorImpl, SelectorIter, SelectorList};
use std::borrow::Borrow;
use tree::Element;
pub use context::*;
// The bloom filter for descendant CSS selectors will have a <1% false
// positive rate until it has this many selectors in it, then it will
// rapidly increase.
pub static RECOMMENDED_SELECTOR_BLOOM_FILTER_SIZE: usize = 4096;
bitflags! {
/// Set of flags that are set on either the element or its parent (depending
/// on the flag) if the element could potentially match a selector.
pub struct ElementSelectorFlags: usize {
/// When a child is added or removed from the parent, all the children
/// must be restyled, because they may match :nth-last-child,
/// :last-of-type, :nth-last-of-type, or :only-of-type.
const HAS_SLOW_SELECTOR = 1 << 0;
/// When a child is added or removed from the parent, any later
/// children must be restyled, because they may match :nth-child,
/// :first-of-type, or :nth-of-type.
const HAS_SLOW_SELECTOR_LATER_SIBLINGS = 1 << 1;
/// When a child is added or removed from the parent, the first and
/// last children must be restyled, because they may match :first-child,
/// :last-child, or :only-child.
const HAS_EDGE_CHILD_SELECTOR = 1 << 2;
/// The element has an empty selector, so when a child is appended we
/// might need to restyle the parent completely.
const HAS_EMPTY_SELECTOR = 1 << 3;
}
}
impl ElementSelectorFlags {
/// Returns the subset of flags that apply to the element.
pub fn for_self(self) -> ElementSelectorFlags {
self & (ElementSelectorFlags::HAS_EMPTY_SELECTOR)
}
/// Returns the subset of flags that apply to the parent.
pub fn for_parent(self) -> ElementSelectorFlags {
self & (ElementSelectorFlags::HAS_SLOW_SELECTOR |
ElementSelectorFlags::HAS_SLOW_SELECTOR_LATER_SIBLINGS |
ElementSelectorFlags::HAS_EDGE_CHILD_SELECTOR)
}
}
/// Holds per-compound-selector data.
struct LocalMatchingContext<'a, 'b: 'a, Impl: SelectorImpl> {
shared: &'a mut MatchingContext<'b, Impl>,
matches_hover_and_active_quirk: bool,
visited_handling: VisitedHandlingMode,
}
#[inline(always)]
pub fn matches_selector_list<E>(
selector_list: &SelectorList<E::Impl>,
element: &E,
context: &mut MatchingContext<E::Impl>,
) -> bool
where
E: Element
{
// This is pretty much any(..) but manually inlined because the compiler
// refuses to do so from querySelector / querySelectorAll.
for selector in &selector_list.0 {
let matches = matches_selector(
selector,
0,
None,
element,
context,
&mut |_, _| {},
);
if matches {
return true;
}
}
false
}
#[inline(always)]
fn may_match(hashes: &AncestorHashes, bf: &BloomFilter) -> bool {
// Check the first three hashes. Note that we can check for zero before
// masking off the high bits, since if any of the first three hashes is
// zero the fourth will be as well. We also take care to avoid the
// special-case complexity of the fourth hash until we actually reach it,
// because we usually don't.
//
// To be clear: this is all extremely hot.
for i in 0..3 {
let packed = hashes.packed_hashes[i];
if packed == 0 {
// No more hashes left - unable to fast-reject.
return true;
}
if !bf.might_contain_hash(packed & BLOOM_HASH_MASK) {
// Hooray! We fast-rejected on this hash.
return false;
}
}
// Now do the slighty-more-complex work of synthesizing the fourth hash,
// and check it against the filter if it exists.
let fourth = hashes.fourth_hash();
fourth == 0 || bf.might_contain_hash(fourth)
}
/// A result of selector matching, includes 3 failure types,
///
/// NotMatchedAndRestartFromClosestLaterSibling
/// NotMatchedAndRestartFromClosestDescendant
/// NotMatchedGlobally
///
/// When NotMatchedGlobally appears, stop selector matching completely since
/// the succeeding selectors never matches.
/// It is raised when
/// Child combinator cannot find the candidate element.
/// Descendant combinator cannot find the candidate element.
///
/// When NotMatchedAndRestartFromClosestDescendant appears, the selector
/// matching does backtracking and restarts from the closest Descendant
/// combinator.
/// It is raised when
/// NextSibling combinator cannot find the candidate element.
/// LaterSibling combinator cannot find the candidate element.
/// Child combinator doesn't match on the found element.
///
/// When NotMatchedAndRestartFromClosestLaterSibling appears, the selector
/// matching does backtracking and restarts from the closest LaterSibling
/// combinator.
/// It is raised when
/// NextSibling combinator doesn't match on the found element.
///
/// For example, when the selector "d1 d2 a" is provided and we cannot *find*
/// an appropriate ancestor element for "d1", this selector matching raises
/// NotMatchedGlobally since even if "d2" is moved to more upper element, the
/// candidates for "d1" becomes less than before and d1 .
///
/// The next example is siblings. When the selector "b1 + b2 ~ d1 a" is
/// provided and we cannot *find* an appropriate brother element for b1,
/// the selector matching raises NotMatchedAndRestartFromClosestDescendant.
/// The selectors ("b1 + b2 ~") doesn't match and matching restart from "d1".
///
/// The additional example is child and sibling. When the selector
/// "b1 + c1 > b2 ~ d1 a" is provided and the selector "b1" doesn't match on
/// the element, this "b1" raises NotMatchedAndRestartFromClosestLaterSibling.
/// However since the selector "c1" raises
/// NotMatchedAndRestartFromClosestDescendant. So the selector
/// "b1 + c1 > b2 ~ " doesn't match and restart matching from "d1".
#[derive(Clone, Copy, Eq, PartialEq)]
enum SelectorMatchingResult {
Matched,
NotMatchedAndRestartFromClosestLaterSibling,
NotMatchedAndRestartFromClosestDescendant,
NotMatchedGlobally,
}
/// Matches a selector, fast-rejecting against a bloom filter.
///
/// We accept an offset to allow consumers to represent and match against
/// partial selectors (indexed from the right). We use this API design, rather
/// than having the callers pass a SelectorIter, because creating a SelectorIter
/// requires dereferencing the selector to get the length, which adds an
/// unncessary cache miss for cases when we can fast-reject with AncestorHashes
/// (which the caller can store inline with the selector pointer).
#[inline(always)]
pub fn matches_selector<E, F>(
selector: &Selector<E::Impl>,
offset: usize,
hashes: Option<&AncestorHashes>,
element: &E,
context: &mut MatchingContext<E::Impl>,
flags_setter: &mut F,
) -> bool
where
E: Element,
F: FnMut(&E, ElementSelectorFlags),
{
// Use the bloom filter to fast-reject.
if let Some(hashes) = hashes {
if let Some(filter) = context.bloom_filter {
if !may_match(hashes, filter) {
return false;
}
}
}
matches_complex_selector(selector.iter_from(offset), element, context, flags_setter)
}
/// Whether a compound selector matched, and whether it was the rightmost
/// selector inside the complex selector.
pub enum CompoundSelectorMatchingResult {
/// The selector was fully matched.
FullyMatched,
/// The compound selector matched, and the next combinator offset is
/// `next_combinator_offset`.
Matched { next_combinator_offset: usize, },
/// The selector didn't match.
NotMatched,
}
/// Matches a compound selector belonging to `selector`, starting at offset
/// `from_offset`, matching left to right.
///
/// Requires that `from_offset` points to a `Combinator`.
///
/// NOTE(emilio): This doesn't allow to match in the leftmost sequence of the
/// complex selector, but it happens to be the case we don't need it.
pub fn matches_compound_selector<E>(
selector: &Selector<E::Impl>,
mut from_offset: usize,
context: &mut MatchingContext<E::Impl>,
element: &E,
) -> CompoundSelectorMatchingResult
where
E: Element
{
if cfg!(debug_assertions) && from_offset != 0 {
selector.combinator_at_parse_order(from_offset - 1); // This asserts.
}
let visited_handling = context.visited_handling;
let mut local_context = LocalMatchingContext {
shared: context,
visited_handling,
matches_hover_and_active_quirk: false,
};
for component in selector.iter_raw_parse_order_from(from_offset) {
if matches!(*component, Component::Combinator(..)) {
debug_assert_ne!(from_offset, 0, "Selector started with a combinator?");
return CompoundSelectorMatchingResult::Matched {
next_combinator_offset: from_offset,
}
}
if !matches_simple_selector(
component,
element,
&mut local_context,
&mut |_, _| {}) {
return CompoundSelectorMatchingResult::NotMatched;
}
from_offset += 1;
}
CompoundSelectorMatchingResult::FullyMatched
}
/// Matches a complex selector.
#[inline(always)]
pub fn matches_complex_selector<E, F>(
mut iter: SelectorIter<E::Impl>,
element: &E,
context: &mut MatchingContext<E::Impl>,
flags_setter: &mut F,
) -> bool
where
E: Element,
F: FnMut(&E, ElementSelectorFlags),
{
// If this is the special pseudo-element mode, consume the ::pseudo-element
// before proceeding, since the caller has already handled that part.
if context.matching_mode == MatchingMode::ForStatelessPseudoElement &&
context.nesting_level == 0 {
// Consume the pseudo.
match *iter.next().unwrap() {
Component::PseudoElement(ref pseudo) => {
if let Some(ref f) = context.pseudo_element_matching_fn {
if !f(pseudo) {
return false;
}
}
}
_ => {
debug_assert!(false,
"Used MatchingMode::ForStatelessPseudoElement \
in a non-pseudo selector");
}
}
// The only other parser-allowed Component in this sequence is a state
// class. We just don't match in that case.
if let Some(s) = iter.next() {
debug_assert!(matches!(*s, Component::NonTSPseudoClass(..)),
"Someone messed up pseudo-element parsing");
return false;
}
// Advance to the non-pseudo-element part of the selector, but let the
// context note that .
if iter.next_sequence().is_none() {
return true;
}
}
let visited_handling = context.visited_handling;
let result = matches_complex_selector_internal(
iter,
element,
context,
visited_handling,
flags_setter,
Rightmost::Yes,
);
match result {
SelectorMatchingResult::Matched => true,
_ => false
}
}
#[inline]
fn matches_hover_and_active_quirk<Impl: SelectorImpl>(
selector_iter: &SelectorIter<Impl>,
context: &MatchingContext<Impl>,
rightmost: Rightmost,
) -> bool {
if context.quirks_mode() != QuirksMode::Quirks {
return false;
}
if context.nesting_level != 0 {
return false;
}
// This compound selector had a pseudo-element to the right that we
// intentionally skipped.
if matches!(rightmost, Rightmost::Yes) &&
context.matching_mode == MatchingMode::ForStatelessPseudoElement {
return false;
}
selector_iter.clone().all(|simple| {
match *simple {
Component::LocalName(_) |
Component::AttributeInNoNamespaceExists { .. } |
Component::AttributeInNoNamespace { .. } |
Component::AttributeOther(_) |
Component::ID(_) |
Component::Class(_) |
Component::PseudoElement(_) |
Component::Negation(_) |
Component::FirstChild |
Component::LastChild |
Component::OnlyChild |
Component::Empty |
Component::NthChild(_, _) |
Component::NthLastChild(_, _) |
Component::NthOfType(_, _) |
Component::NthLastOfType(_, _) |
Component::FirstOfType |
Component::LastOfType |
Component::OnlyOfType => false,
Component::NonTSPseudoClass(ref pseudo_class) => {
Impl::is_active_or_hover(pseudo_class)
},
_ => true,
}
})
}
enum Rightmost {
Yes,
No,
}
#[inline(always)]
fn next_element_for_combinator<E>(
element: &E,
combinator: Combinator,
) -> Option<E>
where
E: Element,
{
match combinator {
Combinator::NextSibling |
Combinator::LaterSibling => {
element.prev_sibling_element()
}
Combinator::Child |
Combinator::Descendant => {
if element.blocks_ancestor_combinators() {
return None;
}
element.parent_element()
}
Combinator::SlotAssignment => {
element.assigned_slot()
}
Combinator::PseudoElement => {
element.pseudo_element_originating_element()
}
}
}
fn matches_complex_selector_internal<E, F>(
mut selector_iter: SelectorIter<E::Impl>,
element: &E,
context: &mut MatchingContext<E::Impl>,
visited_handling: VisitedHandlingMode,
flags_setter: &mut F,
rightmost: Rightmost,
) -> SelectorMatchingResult
where
E: Element,
F: FnMut(&E, ElementSelectorFlags),
{
debug!("Matching complex selector {:?} for {:?}", selector_iter, element);
let matches_all_simple_selectors = {
let matches_hover_and_active_quirk =
matches_hover_and_active_quirk(&selector_iter, context, rightmost);
let mut local_context =
LocalMatchingContext {
shared: context,
visited_handling,
matches_hover_and_active_quirk,
};
selector_iter.all(|simple| {
matches_simple_selector(
simple,
element,
&mut local_context,
flags_setter,
)
})
};
let combinator = selector_iter.next_sequence();
if combinator.map_or(false, |c| c.is_sibling()) {
flags_setter(element, ElementSelectorFlags::HAS_SLOW_SELECTOR_LATER_SIBLINGS);
}
if !matches_all_simple_selectors {
return SelectorMatchingResult::NotMatchedAndRestartFromClosestLaterSibling;
}
let combinator = match combinator {
None => return SelectorMatchingResult::Matched,
Some(c) => c,
};
let candidate_not_found = match combinator {
Combinator::NextSibling |
Combinator::LaterSibling => {
SelectorMatchingResult::NotMatchedAndRestartFromClosestDescendant
}
Combinator::Child |
Combinator::Descendant |
Combinator::SlotAssignment |
Combinator::PseudoElement => {
SelectorMatchingResult::NotMatchedGlobally
}
};
let mut next_element = next_element_for_combinator(element, combinator);
// Stop matching :visited as soon as we find a link, or a combinator for
// something that isn't an ancestor.
let mut visited_handling =
if element.is_link() || combinator.is_sibling() {
VisitedHandlingMode::AllLinksUnvisited
} else {
visited_handling
};
loop {
let element = match next_element {
None => return candidate_not_found,
Some(next_element) => next_element,
};
let result = matches_complex_selector_internal(
selector_iter.clone(),
&element,
context,
visited_handling,
flags_setter,
Rightmost::No,
);
match (result, combinator) {
// Return the status immediately.
(SelectorMatchingResult::Matched, _) |
(SelectorMatchingResult::NotMatchedGlobally, _) |
(_, Combinator::NextSibling) => {
return result;
}
// Upgrade the failure status to
// NotMatchedAndRestartFromClosestDescendant.
(_, Combinator::PseudoElement) |
(_, Combinator::Child) => {
return SelectorMatchingResult::NotMatchedAndRestartFromClosestDescendant;
}
// If the failure status is
// NotMatchedAndRestartFromClosestDescendant and combinator is
// Combinator::LaterSibling, give up this Combinator::LaterSibling
// matching and restart from the closest descendant combinator.
(SelectorMatchingResult::NotMatchedAndRestartFromClosestDescendant, Combinator::LaterSibling) => {
return result;
}
// The Combinator::Descendant combinator and the status is
// NotMatchedAndRestartFromClosestLaterSibling or
// NotMatchedAndRestartFromClosestDescendant, or the
// Combinator::LaterSibling combinator and the status is
// NotMatchedAndRestartFromClosestDescendant, we can continue to
// matching on the next candidate element.
_ => {},
}
visited_handling =
if element.is_link() || combinator.is_sibling() {
VisitedHandlingMode::AllLinksUnvisited
} else {
visited_handling
};
next_element = next_element_for_combinator(&element, combinator);
}
}
/// Determines whether the given element matches the given single selector.
#[inline]
fn matches_simple_selector<E, F>(
selector: &Component<E::Impl>,
element: &E,
context: &mut LocalMatchingContext<E::Impl>,
flags_setter: &mut F,
) -> bool
where
E: Element,
F: FnMut(&E, ElementSelectorFlags),
{
match *selector {
Component::Combinator(_) => unreachable!(),
Component::Slotted(ref selector) => {
context.shared.nesting_level += 1;
let result =
element.assigned_slot().is_some() &&
matches_complex_selector(
selector.iter(),
element,
context.shared,
flags_setter,
);
context.shared.nesting_level -= 1;
result
}
Component::PseudoElement(ref pseudo) => {
element.match_pseudo_element(pseudo, context.shared)
}
Component::LocalName(LocalName { ref name, ref lower_name }) => {
let is_html = element.is_html_element_in_html_document();
element.get_local_name() == select_name(is_html, name, lower_name).borrow()
}
Component::ExplicitUniversalType |
Component::ExplicitAnyNamespace => {
true
}
Component::Namespace(_, ref url) |
Component::DefaultNamespace(ref url) => {
element.get_namespace() == url.borrow()
}
Component::ExplicitNoNamespace => {
let ns = ::parser::namespace_empty_string::<E::Impl>();
element.get_namespace() == ns.borrow()
}
Component::ID(ref id) => {
element.has_id(id, context.shared.classes_and_ids_case_sensitivity())
}
Component::Class(ref class) => {
element.has_class(class, context.shared.classes_and_ids_case_sensitivity())
}
Component::AttributeInNoNamespaceExists { ref local_name, ref local_name_lower } => {
let is_html = element.is_html_element_in_html_document();
element.attr_matches(
&NamespaceConstraint::Specific(&::parser::namespace_empty_string::<E::Impl>()),
select_name(is_html, local_name, local_name_lower),
&AttrSelectorOperation::Exists
)
}
Component::AttributeInNoNamespace {
ref local_name,
ref local_name_lower,
ref value,
operator,
case_sensitivity,
never_matches,
} => {
if never_matches {
return false
}
let is_html = element.is_html_element_in_html_document();
element.attr_matches(
&NamespaceConstraint::Specific(&::parser::namespace_empty_string::<E::Impl>()),
select_name(is_html, local_name, local_name_lower),
&AttrSelectorOperation::WithValue {
operator: operator,
case_sensitivity: case_sensitivity.to_unconditional(is_html),
expected_value: value,
}
)
}
Component::AttributeOther(ref attr_sel) => {
if attr_sel.never_matches {
return false
}
let is_html = element.is_html_element_in_html_document();
element.attr_matches(
&attr_sel.namespace(),
select_name(is_html, &attr_sel.local_name, &attr_sel.local_name_lower),
&match attr_sel.operation {
ParsedAttrSelectorOperation::Exists => AttrSelectorOperation::Exists,
ParsedAttrSelectorOperation::WithValue {
operator,
case_sensitivity,
ref expected_value,
} => {
AttrSelectorOperation::WithValue {
operator: operator,
case_sensitivity: case_sensitivity.to_unconditional(is_html),
expected_value: expected_value,
}
}
}
)
}
Component::NonTSPseudoClass(ref pc) => {
if context.matches_hover_and_active_quirk &&
context.shared.nesting_level == 0 &&
E::Impl::is_active_or_hover(pc) &&
!element.is_link() {
return false;
}
element.match_non_ts_pseudo_class(
pc,
&mut context.shared,
context.visited_handling,
flags_setter
)
}
Component::FirstChild => {
matches_first_child(element, flags_setter)
}
Component::LastChild => {
matches_last_child(element, flags_setter)
}
Component::OnlyChild => {
matches_first_child(element, flags_setter) &&
matches_last_child(element, flags_setter)
}
Component::Root => {
element.is_root()
}
Component::Empty => {
flags_setter(element, ElementSelectorFlags::HAS_EMPTY_SELECTOR);
element.is_empty()
}
Component::Scope => {
match context.shared.scope_element {
Some(ref scope_element) => element.opaque() == *scope_element,
None => element.is_root(),
}
}
Component::NthChild(a, b) => {
matches_generic_nth_child(element, context, a, b, false, false, flags_setter)
}
Component::NthLastChild(a, b) => {
matches_generic_nth_child(element, context, a, b, false, true, flags_setter)
}
Component::NthOfType(a, b) => {
matches_generic_nth_child(element, context, a, b, true, false, flags_setter)
}
Component::NthLastOfType(a, b) => {
matches_generic_nth_child(element, context, a, b, true, true, flags_setter)
}
Component::FirstOfType => {
matches_generic_nth_child(element, context, 0, 1, true, false, flags_setter)
}
Component::LastOfType => {
matches_generic_nth_child(element, context, 0, 1, true, true, flags_setter)
}
Component::OnlyOfType => {
matches_generic_nth_child(element, context, 0, 1, true, false, flags_setter) &&
matches_generic_nth_child(element, context, 0, 1, true, true, flags_setter)
}
Component::Negation(ref negated) => {
context.shared.nesting_level += 1;
let result = !negated.iter().all(|ss| {
matches_simple_selector(
ss,
element,
context,
flags_setter,
)
});
context.shared.nesting_level -= 1;
result
}
}
}
#[inline(always)]
fn select_name<'a, T>(is_html: bool, local_name: &'a T, local_name_lower: &'a T) -> &'a T {
if is_html {
local_name_lower
} else {
local_name
}
}
#[inline]
fn matches_generic_nth_child<E, F>(
element: &E,
context: &mut LocalMatchingContext<E::Impl>,
a: i32,
b: i32,
is_of_type: bool,
is_from_end: bool,
flags_setter: &mut F,
) -> bool
where
E: Element,
F: FnMut(&E, ElementSelectorFlags),
{
if element.ignores_nth_child_selectors() {
return false;
}
flags_setter(element, if is_from_end {
ElementSelectorFlags::HAS_SLOW_SELECTOR
} else {
ElementSelectorFlags::HAS_SLOW_SELECTOR_LATER_SIBLINGS
});
// Grab a reference to the appropriate cache.
let mut cache = context.shared.nth_index_cache.as_mut().map(|c| {
c.get(is_of_type, is_from_end)
});
// Lookup or compute the index.
let index = if let Some(i) = cache.as_mut().and_then(|c| c.lookup(element.opaque())) {
i
} else {
let i = nth_child_index(element, is_of_type, is_from_end, cache.as_mut().map(|s| &mut **s));
cache.as_mut().map(|c| c.insert(element.opaque(), i));
i
};
debug_assert_eq!(index, nth_child_index(element, is_of_type, is_from_end, None), "invalid cache");
// Is there a non-negative integer n such that An+B=index?
match index.checked_sub(b) {
None => false,
Some(an) => match an.checked_div(a) {
Some(n) => n >= 0 && a * n == an,
None /* a == 0 */ => an == 0,
},
}
}
#[inline]
fn same_type<E: Element>(a: &E, b: &E) -> bool {
a.get_local_name() == b.get_local_name() &&
a.get_namespace() == b.get_namespace()
}
#[inline]
fn nth_child_index<E>(
element: &E,
is_of_type: bool,
is_from_end: bool,
mut cache: Option<&mut NthIndexCacheInner>,
) -> i32
where
E: Element,
{
// The traversal mostly processes siblings left to right. So when we walk
// siblings to the right when computing NthLast/NthLastOfType we're unlikely
// to get cache hits along the way. As such, we take the hit of walking the
// siblings to the left checking the cache in the is_from_end case (this
// matches what Gecko does). The indices-from-the-left is handled during the
// regular look further below.
if let Some(ref mut c) = cache {
if is_from_end && !c.is_empty() {
let mut index: i32 = 1;
let mut curr = element.clone();
while let Some(e) = curr.prev_sibling_element() {
curr = e;
if !is_of_type || same_type(element, &curr) {
if let Some(i) = c.lookup(curr.opaque()) {
return i - index;
}
index += 1;
}
}
}
}
let mut index: i32 = 1;
let mut curr = element.clone();
let next = |e: E| if is_from_end { e.next_sibling_element() } else { e.prev_sibling_element() };
while let Some(e) = next(curr) {
curr = e;
if !is_of_type || same_type(element, &curr) {
// If we're computing indices from the left, check each element in the
// cache. We handle the indices-from-the-right case at the top of this
// function.
if !is_from_end {
if let Some(i) = cache.as_mut().and_then(|c| c.lookup(curr.opaque())) {
return i + index
}
}
index += 1;
}
}
index
}
#[inline]
fn matches_first_child<E, F>(element: &E, flags_setter: &mut F) -> bool
where
E: Element,
F: FnMut(&E, ElementSelectorFlags),
{
flags_setter(element, ElementSelectorFlags::HAS_EDGE_CHILD_SELECTOR);
element.prev_sibling_element().is_none()
}
#[inline]
fn matches_last_child<E, F>(element: &E, flags_setter: &mut F) -> bool
where
E: Element,
F: FnMut(&E, ElementSelectorFlags),
{
flags_setter(element, ElementSelectorFlags::HAS_EDGE_CHILD_SELECTOR);
element.next_sibling_element().is_none()
}