mirror of
https://github.com/servo/servo.git
synced 2025-08-07 06:25:32 +01:00
Layout: refactor the box tree update logic for better readability (#37390)
Refactor the box tree update logic to improve readability and facilitate the addition of incremental update logic in the following PRs. Testing: No logic changed, just covered by existing WPT tests Fixes: Nothing to fix Signed-off-by: sharpshooter_pt <ibluegalaxy_taoj@163.com>
This commit is contained in:
JoeDow
GitHub
parent
6818d5c600
commit
5159529888
1 changed files with 191 additions and 162 deletions
|
|
@ -125,168 +125,11 @@ impl BoxTree {
|
|||
/// * how intrinsic content sizes are computed eagerly makes it hard
|
||||
/// to update those sizes for ancestors of the node from which we
|
||||
/// made an incremental update.
|
||||
pub fn update(context: &LayoutContext, mut dirty_node: ServoLayoutNode<'_>) -> bool {
|
||||
#[allow(clippy::enum_variant_names)]
|
||||
enum UpdatePoint {
|
||||
AbsolutelyPositionedBlockLevelBox(ArcRefCell<BlockLevelBox>),
|
||||
AbsolutelyPositionedInlineLevelBox(ArcRefCell<InlineItem>, usize),
|
||||
AbsolutelyPositionedFlexLevelBox(ArcRefCell<FlexLevelBox>),
|
||||
AbsolutelyPositionedTaffyLevelBox(ArcRefCell<TaffyItemBox>),
|
||||
}
|
||||
|
||||
fn update_point(
|
||||
node: ServoLayoutNode<'_>,
|
||||
) -> Option<(Arc<ComputedValues>, DisplayInside, UpdatePoint)> {
|
||||
if !node.is_element() {
|
||||
return None;
|
||||
}
|
||||
|
||||
if node.type_id() == LayoutNodeType::Element(LayoutElementType::HTMLBodyElement) {
|
||||
// This can require changes to the canvas background.
|
||||
return None;
|
||||
}
|
||||
|
||||
// Don't update unstyled nodes or nodes that have pseudo-elements.
|
||||
let element_data = node.style_data()?.element_data.borrow();
|
||||
if !element_data.styles.pseudos.is_empty() {
|
||||
return None;
|
||||
}
|
||||
|
||||
let layout_data = NodeExt::layout_data(&node)?;
|
||||
if layout_data.pseudo_before_box.borrow().is_some() {
|
||||
return None;
|
||||
}
|
||||
if layout_data.pseudo_after_box.borrow().is_some() {
|
||||
return None;
|
||||
}
|
||||
|
||||
let primary_style = element_data.styles.primary();
|
||||
let box_style = primary_style.get_box();
|
||||
|
||||
if !box_style.position.is_absolutely_positioned() {
|
||||
return None;
|
||||
}
|
||||
|
||||
let display_inside = match Display::from(box_style.display) {
|
||||
Display::GeneratingBox(DisplayGeneratingBox::OutsideInside { inside, .. }) => {
|
||||
inside
|
||||
},
|
||||
_ => return None,
|
||||
};
|
||||
|
||||
let update_point =
|
||||
match &*AtomicRef::filter_map(layout_data.self_box.borrow(), Option::as_ref)? {
|
||||
LayoutBox::DisplayContents(..) => return None,
|
||||
LayoutBox::BlockLevel(block_level_box) => match &*block_level_box.borrow() {
|
||||
BlockLevelBox::OutOfFlowAbsolutelyPositionedBox(_)
|
||||
if box_style.position.is_absolutely_positioned() =>
|
||||
{
|
||||
UpdatePoint::AbsolutelyPositionedBlockLevelBox(block_level_box.clone())
|
||||
},
|
||||
_ => return None,
|
||||
},
|
||||
LayoutBox::InlineLevel(inline_level_items) => {
|
||||
let inline_level_box = inline_level_items.first()?;
|
||||
let InlineItem::OutOfFlowAbsolutelyPositionedBox(_, text_offset_index) =
|
||||
&*inline_level_box.borrow()
|
||||
else {
|
||||
return None;
|
||||
};
|
||||
UpdatePoint::AbsolutelyPositionedInlineLevelBox(
|
||||
inline_level_box.clone(),
|
||||
*text_offset_index,
|
||||
)
|
||||
},
|
||||
LayoutBox::FlexLevel(flex_level_box) => match &*flex_level_box.borrow() {
|
||||
FlexLevelBox::OutOfFlowAbsolutelyPositionedBox(_)
|
||||
if box_style.position.is_absolutely_positioned() =>
|
||||
{
|
||||
UpdatePoint::AbsolutelyPositionedFlexLevelBox(flex_level_box.clone())
|
||||
},
|
||||
_ => return None,
|
||||
},
|
||||
LayoutBox::TableLevelBox(..) => return None,
|
||||
LayoutBox::TaffyItemBox(taffy_level_box) => match &taffy_level_box
|
||||
.borrow()
|
||||
.taffy_level_box
|
||||
{
|
||||
TaffyItemBoxInner::OutOfFlowAbsolutelyPositionedBox(_)
|
||||
if box_style.position.is_absolutely_positioned() =>
|
||||
{
|
||||
UpdatePoint::AbsolutelyPositionedTaffyLevelBox(taffy_level_box.clone())
|
||||
},
|
||||
_ => return None,
|
||||
},
|
||||
};
|
||||
Some((primary_style.clone(), display_inside, update_point))
|
||||
}
|
||||
|
||||
loop {
|
||||
let Some((primary_style, display_inside, update_point)) = update_point(dirty_node)
|
||||
else {
|
||||
dirty_node = match dirty_node.parent_node() {
|
||||
Some(parent) => parent,
|
||||
None => return false,
|
||||
};
|
||||
continue;
|
||||
};
|
||||
|
||||
let contents = ReplacedContents::for_element(dirty_node, context)
|
||||
.map_or_else(|| NonReplacedContents::OfElement.into(), Contents::Replaced);
|
||||
let info = NodeAndStyleInfo::new(dirty_node, Arc::clone(&primary_style));
|
||||
let out_of_flow_absolutely_positioned_box = ArcRefCell::new(
|
||||
AbsolutelyPositionedBox::construct(context, &info, display_inside, contents),
|
||||
);
|
||||
match update_point {
|
||||
UpdatePoint::AbsolutelyPositionedBlockLevelBox(block_level_box) => {
|
||||
*block_level_box.borrow_mut() = BlockLevelBox::OutOfFlowAbsolutelyPositionedBox(
|
||||
out_of_flow_absolutely_positioned_box,
|
||||
);
|
||||
},
|
||||
UpdatePoint::AbsolutelyPositionedInlineLevelBox(
|
||||
inline_level_box,
|
||||
text_offset_index,
|
||||
) => {
|
||||
*inline_level_box.borrow_mut() = InlineItem::OutOfFlowAbsolutelyPositionedBox(
|
||||
out_of_flow_absolutely_positioned_box,
|
||||
text_offset_index,
|
||||
);
|
||||
},
|
||||
UpdatePoint::AbsolutelyPositionedFlexLevelBox(flex_level_box) => {
|
||||
*flex_level_box.borrow_mut() = FlexLevelBox::OutOfFlowAbsolutelyPositionedBox(
|
||||
out_of_flow_absolutely_positioned_box,
|
||||
);
|
||||
},
|
||||
UpdatePoint::AbsolutelyPositionedTaffyLevelBox(taffy_level_box) => {
|
||||
taffy_level_box.borrow_mut().taffy_level_box =
|
||||
TaffyItemBoxInner::OutOfFlowAbsolutelyPositionedBox(
|
||||
out_of_flow_absolutely_positioned_box,
|
||||
);
|
||||
},
|
||||
}
|
||||
break;
|
||||
}
|
||||
|
||||
// We are going to rebuild the box tree from the update point downward, but this update
|
||||
// point is an absolute, which means that it needs to be laid out again in the containing
|
||||
// block for absolutes, which is established by one of its ancestors. In addition,
|
||||
// absolutes, when laid out, can produce more absolutes (either fixed or absolutely
|
||||
// positioned) elements, so there may be yet more layout that has to happen in this
|
||||
// ancestor.
|
||||
//
|
||||
// We do not know which ancestor is the one that established the containing block for this
|
||||
// update point, so just invalidate the fragment cache of all ancestors, meaning that even
|
||||
// though the box tree is preserved, the fragment tree from the root to the update point and
|
||||
// all of its descendants will need to be rebuilt. This isn't as bad as it seems, because
|
||||
// siblings and siblings of ancestors of this path through the tree will still have cached
|
||||
// fragments.
|
||||
//
|
||||
// TODO: Do better. This is still a very crude way to do incremental layout.
|
||||
while let Some(parent_node) = dirty_node.parent_node() {
|
||||
parent_node.invalidate_cached_fragment();
|
||||
dirty_node = parent_node;
|
||||
}
|
||||
|
||||
pub fn update(context: &LayoutContext, dirty_root_from_script: ServoLayoutNode<'_>) -> bool {
|
||||
let Some(box_tree_update) = IncrementalBoxTreeUpdate::find(dirty_root_from_script) else {
|
||||
return false;
|
||||
};
|
||||
box_tree_update.update_from_dirty_root(context);
|
||||
true
|
||||
}
|
||||
}
|
||||
|
|
@ -400,3 +243,189 @@ impl BoxTree {
|
|||
)
|
||||
}
|
||||
}
|
||||
|
||||
#[allow(clippy::enum_variant_names)]
|
||||
enum DirtyRootBoxTreeNode {
|
||||
AbsolutelyPositionedBlockLevelBox(ArcRefCell<BlockLevelBox>),
|
||||
AbsolutelyPositionedInlineLevelBox(ArcRefCell<InlineItem>, usize),
|
||||
AbsolutelyPositionedFlexLevelBox(ArcRefCell<FlexLevelBox>),
|
||||
AbsolutelyPositionedTaffyLevelBox(ArcRefCell<TaffyItemBox>),
|
||||
}
|
||||
|
||||
struct IncrementalBoxTreeUpdate<'dom> {
|
||||
node: ServoLayoutNode<'dom>,
|
||||
box_tree_node: DirtyRootBoxTreeNode,
|
||||
primary_style: Arc<ComputedValues>,
|
||||
display_inside: DisplayInside,
|
||||
}
|
||||
|
||||
impl<'dom> IncrementalBoxTreeUpdate<'dom> {
|
||||
fn find(dirty_root_from_script: ServoLayoutNode<'dom>) -> Option<Self> {
|
||||
let mut maybe_dirty_root_node = Some(dirty_root_from_script);
|
||||
while let Some(dirty_root_node) = maybe_dirty_root_node {
|
||||
if let Some(dirty_root) = Self::new_if_valid(dirty_root_node) {
|
||||
return Some(dirty_root);
|
||||
}
|
||||
|
||||
maybe_dirty_root_node = dirty_root_node.parent_node();
|
||||
}
|
||||
|
||||
None
|
||||
}
|
||||
|
||||
fn new_if_valid(potential_dirty_root_node: ServoLayoutNode<'dom>) -> Option<Self> {
|
||||
if !potential_dirty_root_node.is_element() {
|
||||
return None;
|
||||
}
|
||||
|
||||
if potential_dirty_root_node.type_id() ==
|
||||
LayoutNodeType::Element(LayoutElementType::HTMLBodyElement)
|
||||
{
|
||||
// This can require changes to the canvas background.
|
||||
return None;
|
||||
}
|
||||
|
||||
// Don't update unstyled nodes or nodes that have pseudo-elements.
|
||||
let element_data = potential_dirty_root_node
|
||||
.style_data()?
|
||||
.element_data
|
||||
.borrow();
|
||||
if !element_data.styles.pseudos.is_empty() {
|
||||
return None;
|
||||
}
|
||||
|
||||
let layout_data = NodeExt::layout_data(&potential_dirty_root_node)?;
|
||||
if layout_data.pseudo_before_box.borrow().is_some() {
|
||||
return None;
|
||||
}
|
||||
if layout_data.pseudo_after_box.borrow().is_some() {
|
||||
return None;
|
||||
}
|
||||
|
||||
let primary_style = element_data.styles.primary();
|
||||
let box_style = primary_style.get_box();
|
||||
|
||||
if !box_style.position.is_absolutely_positioned() {
|
||||
return None;
|
||||
}
|
||||
|
||||
let display_inside = match Display::from(box_style.display) {
|
||||
Display::GeneratingBox(DisplayGeneratingBox::OutsideInside { inside, .. }) => inside,
|
||||
_ => return None,
|
||||
};
|
||||
|
||||
let box_tree_node =
|
||||
match &*AtomicRef::filter_map(layout_data.self_box.borrow(), Option::as_ref)? {
|
||||
LayoutBox::DisplayContents(..) => return None,
|
||||
LayoutBox::BlockLevel(block_level_box) => match &*block_level_box.borrow() {
|
||||
BlockLevelBox::OutOfFlowAbsolutelyPositionedBox(_)
|
||||
if box_style.position.is_absolutely_positioned() =>
|
||||
{
|
||||
DirtyRootBoxTreeNode::AbsolutelyPositionedBlockLevelBox(
|
||||
block_level_box.clone(),
|
||||
)
|
||||
},
|
||||
_ => return None,
|
||||
},
|
||||
LayoutBox::InlineLevel(inline_level_items) => {
|
||||
let inline_level_box = inline_level_items.first()?;
|
||||
let InlineItem::OutOfFlowAbsolutelyPositionedBox(_, text_offset_index) =
|
||||
&*inline_level_box.borrow()
|
||||
else {
|
||||
return None;
|
||||
};
|
||||
DirtyRootBoxTreeNode::AbsolutelyPositionedInlineLevelBox(
|
||||
inline_level_box.clone(),
|
||||
*text_offset_index,
|
||||
)
|
||||
},
|
||||
LayoutBox::FlexLevel(flex_level_box) => match &*flex_level_box.borrow() {
|
||||
FlexLevelBox::OutOfFlowAbsolutelyPositionedBox(_)
|
||||
if box_style.position.is_absolutely_positioned() =>
|
||||
{
|
||||
DirtyRootBoxTreeNode::AbsolutelyPositionedFlexLevelBox(
|
||||
flex_level_box.clone(),
|
||||
)
|
||||
},
|
||||
_ => return None,
|
||||
},
|
||||
LayoutBox::TableLevelBox(..) => return None,
|
||||
LayoutBox::TaffyItemBox(taffy_level_box) => {
|
||||
match &taffy_level_box.borrow().taffy_level_box {
|
||||
TaffyItemBoxInner::OutOfFlowAbsolutelyPositionedBox(_)
|
||||
if box_style.position.is_absolutely_positioned() =>
|
||||
{
|
||||
DirtyRootBoxTreeNode::AbsolutelyPositionedTaffyLevelBox(
|
||||
taffy_level_box.clone(),
|
||||
)
|
||||
},
|
||||
_ => return None,
|
||||
}
|
||||
},
|
||||
};
|
||||
|
||||
Some(Self {
|
||||
node: potential_dirty_root_node,
|
||||
box_tree_node,
|
||||
primary_style: primary_style.clone(),
|
||||
display_inside,
|
||||
})
|
||||
}
|
||||
|
||||
fn update_from_dirty_root(&self, context: &LayoutContext) {
|
||||
let contents = ReplacedContents::for_element(self.node, context)
|
||||
.map_or_else(|| NonReplacedContents::OfElement.into(), Contents::Replaced);
|
||||
let info = NodeAndStyleInfo::new(self.node, self.primary_style.clone());
|
||||
let out_of_flow_absolutely_positioned_box = ArcRefCell::new(
|
||||
AbsolutelyPositionedBox::construct(context, &info, self.display_inside, contents),
|
||||
);
|
||||
match &self.box_tree_node {
|
||||
DirtyRootBoxTreeNode::AbsolutelyPositionedBlockLevelBox(block_level_box) => {
|
||||
*block_level_box.borrow_mut() = BlockLevelBox::OutOfFlowAbsolutelyPositionedBox(
|
||||
out_of_flow_absolutely_positioned_box,
|
||||
);
|
||||
},
|
||||
DirtyRootBoxTreeNode::AbsolutelyPositionedInlineLevelBox(
|
||||
inline_level_box,
|
||||
text_offset_index,
|
||||
) => {
|
||||
*inline_level_box.borrow_mut() = InlineItem::OutOfFlowAbsolutelyPositionedBox(
|
||||
out_of_flow_absolutely_positioned_box,
|
||||
*text_offset_index,
|
||||
);
|
||||
},
|
||||
DirtyRootBoxTreeNode::AbsolutelyPositionedFlexLevelBox(flex_level_box) => {
|
||||
*flex_level_box.borrow_mut() = FlexLevelBox::OutOfFlowAbsolutelyPositionedBox(
|
||||
out_of_flow_absolutely_positioned_box,
|
||||
);
|
||||
},
|
||||
DirtyRootBoxTreeNode::AbsolutelyPositionedTaffyLevelBox(taffy_level_box) => {
|
||||
taffy_level_box.borrow_mut().taffy_level_box =
|
||||
TaffyItemBoxInner::OutOfFlowAbsolutelyPositionedBox(
|
||||
out_of_flow_absolutely_positioned_box,
|
||||
);
|
||||
},
|
||||
}
|
||||
|
||||
// We are going to rebuild the box tree from the update point downward, but this update
|
||||
// point is an absolute, which means that it needs to be laid out again in the containing
|
||||
// block for absolutes, which is established by one of its ancestors. In addition,
|
||||
// absolutes, when laid out, can produce more absolutes (either fixed or absolutely
|
||||
// positioned) elements, so there may be yet more layout that has to happen in this
|
||||
// ancestor.
|
||||
//
|
||||
// We do not know which ancestor is the one that established the containing block for this
|
||||
// update point, so just invalidate the fragment cache of all ancestors, meaning that even
|
||||
// though the box tree is preserved, the fragment tree from the root to the update point and
|
||||
// all of its descendants will need to be rebuilt. This isn't as bad as it seems, because
|
||||
// siblings and siblings of ancestors of this path through the tree will still have cached
|
||||
// fragments.
|
||||
//
|
||||
// TODO: Do better. This is still a very crude way to do incremental layout.
|
||||
let mut invalidate_start_point = self.node;
|
||||
while let Some(parent_node) = invalidate_start_point.parent_node() {
|
||||
parent_node.invalidate_cached_fragment();
|
||||
invalidate_start_point = parent_node;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue