style: Properly distinguish between empty children and no children in rule iterator.

So that skip_children(), which just pops the stack and is used by the
dynamic media query evaluation code, works as it should.

Differential Revision: https://phabricator.services.mozilla.com/D92717
This commit is contained in:
Emilio Cobos Álvarez 2020-10-08 05:39:33 +00:00
parent 384fd59ad0
commit 2b55918be6

View file

@ -60,7 +60,7 @@ fn children_of_rule<'a, C>(
quirks_mode: QuirksMode,
guard: &'a SharedRwLockReadGuard<'_>,
effective: &mut bool,
) -> slice::Iter<'a, CssRule>
) -> Option<slice::Iter<'a, CssRule>>
where
C: NestedRuleIterationCondition + 'static,
{
@ -73,38 +73,38 @@ where
CssRule::Viewport(_) |
CssRule::Keyframes(_) |
CssRule::Page(_) |
CssRule::FontFeatureValues(_) => [].iter(),
CssRule::FontFeatureValues(_) => None,
CssRule::Import(ref import_rule) => {
let import_rule = import_rule.read_with(guard);
if !C::process_import(guard, device, quirks_mode, import_rule) {
*effective = false;
return [].iter();
return None;
}
import_rule.stylesheet.rules(guard).iter()
Some(import_rule.stylesheet.rules(guard).iter())
},
CssRule::Document(ref doc_rule) => {
let doc_rule = doc_rule.read_with(guard);
if !C::process_document(guard, device, quirks_mode, doc_rule) {
*effective = false;
return [].iter();
return None;
}
doc_rule.rules.read_with(guard).0.iter()
Some(doc_rule.rules.read_with(guard).0.iter())
},
CssRule::Media(ref lock) => {
let media_rule = lock.read_with(guard);
if !C::process_media(guard, device, quirks_mode, media_rule) {
*effective = false;
return [].iter();
return None;
}
media_rule.rules.read_with(guard).0.iter()
Some(media_rule.rules.read_with(guard).0.iter())
},
CssRule::Supports(ref lock) => {
let supports_rule = lock.read_with(guard);
if !C::process_supports(guard, device, quirks_mode, supports_rule) {
*effective = false;
return [].iter();
return None;
}
supports_rule.rules.read_with(guard).0.iter()
Some(supports_rule.rules.read_with(guard).0.iter())
},
}
}
@ -135,7 +135,9 @@ where
continue;
}
if !children.as_slice().is_empty() {
if let Some(children) = children {
// NOTE: It's important that `children` gets pushed even if
// empty, so that `skip_children()` works as expected.
self.stack.push(children);
}
@ -306,6 +308,6 @@ impl<'a, 'b> EffectiveRulesIterator<'a, 'b> {
rule: &'a CssRule,
) -> Self {
let children = children_of_rule::<AllRules>(rule, device, quirks_mode, guard, &mut false);
EffectiveRulesIterator::new(device, quirks_mode, guard, children)
EffectiveRulesIterator::new(device, quirks_mode, guard, children.unwrap_or([].iter()))
}
}