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Backed out changeset dbd300f4d75b for build bustage. r=backout on a CLOSED TREE

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Backs out https://github.com/servo/servo/pull/19108
This commit is contained in:
Gecko Backout 2017-11-03 23:56:42 +00:00 • committed by moz-servo-sync
parent a0cd781bdc
commit 8f8fd517ed
8 changed files with 60 additions and 371 deletions
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315
components/style/dom_apis.rs
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@ -5,16 +5,12 @@
//! Generic implementations of some DOM APIs so they can be shared between Servo
//! and Gecko.
use Atom;
use context::QuirksMode;
use dom::{TDocument, TElement, TNode};
use invalidation::element::invalidator::{Invalidation, InvalidationProcessor, InvalidationVector};
use selectors::{Element, NthIndexCache, SelectorList};
use selectors::attr::CaseSensitivity;
use selectors::matching::{self, MatchingContext, MatchingMode};
use selectors::parser::{Combinator, Component, LocalName};
use smallvec::SmallVec;
use std::borrow::Borrow;
/// <https://dom.spec.whatwg.org/#dom-element-matches>
pub fn element_matches<E>(
@ -222,103 +218,13 @@ where
}
}
/// Returns whether a given element is descendant of a given `root` node.
/// Fast paths for a given selector query.
///
/// NOTE(emilio): if root == element, this returns false.
fn element_is_descendant_of<E>(element: E, root: E::ConcreteNode) -> bool
where
E: TElement,
{
if element.as_node().is_in_document() && root == root.owner_doc().as_node() {
return true;
}
let mut current = element.as_node().parent_node();
while let Some(n) = current.take() {
if n == root {
return true;
}
current = n.parent_node();
}
false
}
/// Fast path for iterating over every element with a given id in the document
/// that `root` is connected to.
fn fast_connected_elements_with_id<'a, D>(
doc: &'a D,
root: D::ConcreteNode,
id: &Atom,
quirks_mode: QuirksMode,
) -> Result<&'a [<D::ConcreteNode as TNode>::ConcreteElement], ()>
where
D: TDocument,
{
debug_assert_eq!(root.owner_doc().as_node(), doc.as_node());
let case_sensitivity = quirks_mode.classes_and_ids_case_sensitivity();
if case_sensitivity != CaseSensitivity::CaseSensitive {
return Err(());
}
if !root.is_in_document() {
return Err(());
}
doc.elements_with_id(id)
}
/// Collects elements with a given id under `root`, that pass `filter`.
fn collect_elements_with_id<E, Q, F>(
/// FIXME(emilio, nbp): This may very well be a good candidate for code to be
/// replaced by HolyJit :)
fn query_selector_fast<E, Q>(
root: E::ConcreteNode,
id: &Atom,
results: &mut Q::Output,
quirks_mode: QuirksMode,
mut filter: F,
)
where
E: TElement,
Q: SelectorQuery<E>,
F: FnMut(E) -> bool,
{
let doc = root.owner_doc();
let elements = match fast_connected_elements_with_id(&doc, root, id, quirks_mode) {
Ok(elements) => elements,
Err(()) => {
let case_sensitivity =
quirks_mode.classes_and_ids_case_sensitivity();
collect_all_elements::<E, Q, _>(root, results, |e| {
e.has_id(id, case_sensitivity) && filter(e)
});
return;
}
};
for element in elements {
// If the element is not an actual descendant of the root, even though
// it's connected, we don't really care about it.
if !element_is_descendant_of(*element, root) {
continue;
}
if !filter(*element) {
continue;
}
Q::append_element(results, *element);
if Q::should_stop_after_first_match() {
break;
}
}
}
/// Fast paths for querySelector with a single simple selector.
fn query_selector_single_query<E, Q>(
root: E::ConcreteNode,
component: &Component<E::Impl>,
selector_list: &SelectorList<E::Impl>,
results: &mut Q::Output,
quirks_mode: QuirksMode,
) -> Result<(), ()>
@ -326,18 +232,36 @@ where
E: TElement,
Q: SelectorQuery<E>,
{
use selectors::parser::{Component, LocalName};
use std::borrow::Borrow;
// We need to return elements in document order, and reordering them
// afterwards is kinda silly.
if selector_list.0.len() > 1 {
return Err(());
}
let selector = &selector_list.0[0];
// Let's just care about the easy cases for now.
//
// FIXME(emilio): Blink has a fast path for classes in ancestor combinators
// that may be worth stealing.
if selector.len() > 1 {
return Err(());
}
let component = selector.iter().next().unwrap();
match *component {
Component::ExplicitUniversalType => {
collect_all_elements::<E, Q, _>(root, results, |_| true)
}
Component::ID(ref id) => {
collect_elements_with_id::<E, Q, _>(
root,
id,
results,
quirks_mode,
|_| true,
);
// TODO(emilio): We may want to reuse Gecko's document ID table.
let case_sensitivity = quirks_mode.classes_and_ids_case_sensitivity();
collect_all_elements::<E, Q, _>(root, results, |element| {
element.has_id(id, case_sensitivity)
})
}
Component::Class(ref class) => {
let case_sensitivity = quirks_mode.classes_and_ids_case_sensitivity();
@ -363,139 +287,6 @@ where
Ok(())
}
/// Fast paths for a given selector query.
///
/// FIXME(emilio, nbp): This may very well be a good candidate for code to be
/// replaced by HolyJit :)
fn query_selector_fast<E, Q>(
root: E::ConcreteNode,
selector_list: &SelectorList<E::Impl>,
results: &mut Q::Output,
matching_context: &mut MatchingContext<E::Impl>,
) -> Result<(), ()>
where
E: TElement,
Q: SelectorQuery<E>,
{
// We need to return elements in document order, and reordering them
// afterwards is kinda silly.
if selector_list.0.len() > 1 {
return Err(());
}
let selector = &selector_list.0[0];
let quirks_mode = matching_context.quirks_mode();
// Let's just care about the easy cases for now.
if selector.len() == 1 {
return query_selector_single_query::<E, Q>(
root,
selector.iter().next().unwrap(),
results,
quirks_mode,
);
}
let mut iter = selector.iter();
let mut combinator: Option<Combinator> = None;
loop {
debug_assert!(combinator.map_or(true, |c| !c.is_sibling()));
'component_loop: for component in &mut iter {
match *component {
Component::ID(ref id) => {
if combinator.is_none() {
// In the rightmost compound, just find descendants of
// root that match the selector list with that id.
collect_elements_with_id::<E, Q, _>(
root,
id,
results,
quirks_mode,
|e| {
matching::matches_selector_list(
selector_list,
&e,
matching_context,
)
}
);
return Ok(());
}
let doc = root.owner_doc();
let elements =
fast_connected_elements_with_id(&doc, root, id, quirks_mode)?;
if elements.is_empty() {
return Ok(());
}
// Results need to be in document order. Let's not bother
// reordering or deduplicating nodes, which we would need to
// do if one element with the given id were a descendant of
// another element with that given id.
if !Q::should_stop_after_first_match() && elements.len() > 1 {
continue;
}
for element in elements {
// If the element is not a descendant of the root, then
// it may have descendants that match our selector that
// _are_ descendants of the root, and other descendants
// that match our selector that are _not_.
//
// So we can't just walk over the element's descendants
// and match the selector against all of them, nor can
// we skip looking at this element's descendants.
//
// Give up on trying to optimize based on this id and
// keep walking our selector.
if !element_is_descendant_of(*element, root) {
continue 'component_loop;
}
query_selector_slow::<E, Q>(
element.as_node(),
selector_list,
results,
matching_context,
);
if Q::should_stop_after_first_match() && !Q::is_empty(&results) {
break;
}
}
return Ok(());
}
_ => {},
}
}
loop {
let next_combinator = match iter.next_sequence() {
None => return Err(()),
Some(c) => c,
};
// We don't want to scan stuff affected by sibling combinators,
// given we scan the subtree of elements with a given id (and we
// don't want to care about scanning the siblings' subtrees).
if next_combinator.is_sibling() {
// Advance to the next combinator.
for _ in &mut iter {}
continue;
}
combinator = Some(next_combinator);
break;
}
}
}
// Slow path for a given selector query.
fn query_selector_slow<E, Q>(
root: E::ConcreteNode,
@ -512,21 +303,11 @@ where
});
}
/// Whether the invalidation machinery should be used for this query.
#[derive(PartialEq)]
pub enum MayUseInvalidation {
/// We may use it if we deem it useful.
Yes,
/// Don't use it.
No,
}
/// <https://dom.spec.whatwg.org/#dom-parentnode-queryselector>
pub fn query_selector<E, Q>(
root: E::ConcreteNode,
selector_list: &SelectorList<E::Impl>,
results: &mut Q::Output,
may_use_invalidation: MayUseInvalidation,
)
where
E: TElement,
@ -535,7 +316,21 @@ where
use invalidation::element::invalidator::TreeStyleInvalidator;
let quirks_mode = root.owner_doc().quirks_mode();
let fast_result = query_selector_fast::<E, Q>(
root,
selector_list,
results,
quirks_mode,
);
if fast_result.is_ok() {
return;
}
// Slow path: Use the invalidation machinery if we're a root, and tree
// traversal otherwise.
//
// See the comment in collect_invalidations to see why only if we're a root.
let mut nth_index_cache = NthIndexCache::default();
let mut matching_context = MatchingContext::new(
MatchingMode::Normal,
@ -547,32 +342,12 @@ where
let root_element = root.as_element();
matching_context.scope_element = root_element.map(|e| e.opaque());
let fast_result = query_selector_fast::<E, Q>(
root,
selector_list,
results,
&mut matching_context,
);
if fast_result.is_ok() {
return;
}
// Slow path: Use the invalidation machinery if we're a root, and tree
// traversal otherwise.
//
// See the comment in collect_invalidations to see why only if we're a root.
//
// The invalidation mechanism is only useful in presence of combinators.
//
// We could do that check properly here, though checking the length of the
// selectors is a good heuristic.
//
// A selector with a combinator needs to have a length of at least 3: A
// simple selector, a combinator, and another simple selector.
let invalidation_may_be_useful =
may_use_invalidation == MayUseInvalidation::Yes &&
selector_list.0.iter().any(|s| s.len() > 2);
selector_list.0.iter().any(|s| s.len() > 1);
if root_element.is_some() || !invalidation_may_be_useful {
query_selector_slow::<E, Q>(