layout: Add incremental box tree construction for inline floats and abspos (#37892)

Layout: Add incremental box tree construction for inline floats and
abspos

Due to false positives in the memory benchmark on CI, the previous PR
[37868](https://github.com/servo/servo/pull/37868) reverted. Now it is
resubmitted.

Signed-off-by: sharpshooter_pt <ibluegalaxy_taoj@163.com>
This commit is contained in:
JoeDow 2025-07-05 16:33:04 +08:00 committed by GitHub
parent c65cd1eadd
commit 864c877be5
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GPG key ID: B5690EEEBB952194
3 changed files with 66 additions and 28 deletions

View file

@ -136,6 +136,20 @@ impl LayoutBox {
.repair_style(context, node, new_style),
}
}
/// If this [`LayoutBox`] represents an unsplit (due to inline-block splits) inline
/// level item, unwrap and return it. If not, return `None`.
pub(crate) fn unsplit_inline_level_layout_box(self) -> Option<ArcRefCell<InlineItem>> {
let LayoutBox::InlineLevel(inline_level_boxes) = self else {
return None;
};
// If this element box has been subject to inline-block splitting, ignore it. It's
// not useful currently for incremental box tree construction.
if inline_level_boxes.len() != 1 {
return None;
}
inline_level_boxes.into_iter().next()
}
}
/// A wrapper for [`InnerDOMLayoutData`]. This is necessary to give the entire data

View file

@ -604,13 +604,17 @@ impl<'dom> BlockContainerBuilder<'dom, '_> {
) {
if let Some(builder) = self.inline_formatting_context_builder.as_mut() {
if !builder.is_empty() {
let inline_level_box =
builder.push_absolutely_positioned_box(AbsolutelyPositionedBox::construct(
let constructor = || {
ArcRefCell::new(AbsolutelyPositionedBox::construct(
self.context,
info,
display_inside,
contents,
));
))
};
let old_layout_box = box_slot.take_layout_box_if_undamaged(info.damage);
let inline_level_box =
builder.push_absolutely_positioned_box(constructor, old_layout_box);
box_slot.set(LayoutBox::InlineLevel(vec![inline_level_box]));
return;
}
@ -637,13 +641,17 @@ impl<'dom> BlockContainerBuilder<'dom, '_> {
) {
if let Some(builder) = self.inline_formatting_context_builder.as_mut() {
if !builder.is_empty() {
let inline_level_box = builder.push_float_box(FloatBox::construct(
let constructor = || {
ArcRefCell::new(FloatBox::construct(
self.context,
info,
display_inside,
contents,
self.propagated_data,
));
))
};
let old_layout_box = box_slot.take_layout_box_if_undamaged(info.damage);
let inline_level_box = builder.push_float_box(constructor, old_layout_box);
box_slot.set(LayoutBox::InlineLevel(vec![inline_level_box]));
return;
}

View file

@ -160,19 +160,10 @@ impl InlineFormattingContextBuilder {
) -> ArcRefCell<InlineItem> {
// If there is an existing undamaged layout box that's compatible, use that.
let independent_formatting_context = old_layout_box
.and_then(|layout_box| {
let LayoutBox::InlineLevel(inline_level_boxes) = layout_box else {
return None;
};
// If there's an existing box, it should be a compatible atomic inline and should
// not have been subject to inline-block splitting.
assert_eq!(inline_level_boxes.len(), 1);
let first_box = inline_level_boxes.into_iter().next()?;
match &*first_box.borrow() {
.and_then(LayoutBox::unsplit_inline_level_layout_box)
.and_then(|inline_item| match &*inline_item.borrow() {
InlineItem::Atomic(atomic, ..) => Some(atomic.clone()),
_ => None,
}
})
.unwrap_or_else(independent_formatting_context_creator);
@ -195,9 +186,20 @@ impl InlineFormattingContextBuilder {
pub(crate) fn push_absolutely_positioned_box(
&mut self,
absolutely_positioned_box: AbsolutelyPositionedBox,
absolutely_positioned_box_creator: impl FnOnce() -> ArcRefCell<AbsolutelyPositionedBox>,
old_layout_box: Option<LayoutBox>,
) -> ArcRefCell<InlineItem> {
let absolutely_positioned_box = ArcRefCell::new(absolutely_positioned_box);
let absolutely_positioned_box = old_layout_box
.and_then(LayoutBox::unsplit_inline_level_layout_box)
.and_then(|inline_item| match &*inline_item.borrow() {
InlineItem::OutOfFlowAbsolutelyPositionedBox(positioned_box, ..) => {
Some(positioned_box.clone())
},
_ => None,
})
.unwrap_or_else(absolutely_positioned_box_creator);
// We cannot just reuse the old inline item, because the `current_text_offset` may have changed.
let inline_level_box = ArcRefCell::new(InlineItem::OutOfFlowAbsolutelyPositionedBox(
absolutely_positioned_box,
self.current_text_offset,
@ -207,9 +209,23 @@ impl InlineFormattingContextBuilder {
inline_level_box
}
pub(crate) fn push_float_box(&mut self, float_box: FloatBox) -> ArcRefCell<InlineItem> {
let inline_level_box =
ArcRefCell::new(InlineItem::OutOfFlowFloatBox(ArcRefCell::new(float_box)));
pub(crate) fn push_float_box(
&mut self,
float_box_creator: impl FnOnce() -> ArcRefCell<FloatBox>,
old_layout_box: Option<LayoutBox>,
) -> ArcRefCell<InlineItem> {
let inline_level_box = old_layout_box
.and_then(LayoutBox::unsplit_inline_level_layout_box)
.unwrap_or_else(|| ArcRefCell::new(InlineItem::OutOfFlowFloatBox(float_box_creator())));
debug_assert!(
matches!(
&*inline_level_box.borrow(),
InlineItem::OutOfFlowFloatBox(..),
),
"Created float box with incompatible `old_layout_box`"
);
self.inline_items.push(inline_level_box.clone());
self.contains_floats = true;
inline_level_box