servo/components/layout/dom.rs
Martin Robinson 69ff4afa58
Rename script_layout_interface to layout_api (#37591)
Now that we are standardizing on the `_traits` crates becoming `_api`
and exposing the API of the crate that they get their name from [^1],
`script_layout_interface` becomes `layout_api` as it exposes the API for
`layout` that is used by `script` This brings the crate in line with the
naming of the other ones in `shared`.

[^1]:
https://servo.zulipchat.com/#narrow/channel/263398-general/topic/Organizing.20*_traits.20crates/with/396893711

Testing: This should not change any behavior and thus is covered by
existing tests.

Signed-off-by: Martin Robinson <mrobinson@igalia.com>
2025-06-20 17:13:05 +00:00

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/* 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 https://mozilla.org/MPL/2.0/. */
use std::any::Any;
use std::marker::PhantomData;
use atomic_refcell::{AtomicRef, AtomicRefCell, AtomicRefMut};
use base::id::{BrowsingContextId, PipelineId};
use html5ever::{local_name, ns};
use layout_api::wrapper_traits::{
LayoutDataTrait, LayoutNode, ThreadSafeLayoutElement, ThreadSafeLayoutNode,
};
use layout_api::{
GenericLayoutDataTrait, LayoutElementType, LayoutNodeType as ScriptLayoutNodeType,
};
use malloc_size_of_derive::MallocSizeOf;
use net_traits::image_cache::Image;
use script::layout_dom::ServoLayoutNode;
use servo_arc::Arc as ServoArc;
use style::context::SharedStyleContext;
use style::properties::ComputedValues;
use style::selector_parser::PseudoElement;
use crate::cell::ArcRefCell;
use crate::flexbox::FlexLevelBox;
use crate::flow::BlockLevelBox;
use crate::flow::inline::{InlineItem, SharedInlineStyles};
use crate::fragment_tree::Fragment;
use crate::geom::PhysicalSize;
use crate::replaced::CanvasInfo;
use crate::table::TableLevelBox;
use crate::taffy::TaffyItemBox;
/// The data that is stored in each DOM node that is used by layout.
#[derive(Default, MallocSizeOf)]
pub struct InnerDOMLayoutData {
pub(super) self_box: ArcRefCell<Option<LayoutBox>>,
pub(super) pseudo_before_box: ArcRefCell<Option<LayoutBox>>,
pub(super) pseudo_after_box: ArcRefCell<Option<LayoutBox>>,
pub(super) pseudo_marker_box: ArcRefCell<Option<LayoutBox>>,
}
impl InnerDOMLayoutData {
pub(crate) fn for_pseudo(
&self,
pseudo_element: Option<PseudoElement>,
) -> AtomicRef<Option<LayoutBox>> {
match pseudo_element {
Some(PseudoElement::Before) => self.pseudo_before_box.borrow(),
Some(PseudoElement::After) => self.pseudo_after_box.borrow(),
Some(PseudoElement::Marker) => self.pseudo_marker_box.borrow(),
_ => self.self_box.borrow(),
}
}
}
/// A box that is stored in one of the `DOMLayoutData` slots.
#[derive(MallocSizeOf)]
pub(super) enum LayoutBox {
DisplayContents(SharedInlineStyles),
BlockLevel(ArcRefCell<BlockLevelBox>),
InlineLevel(Vec<ArcRefCell<InlineItem>>),
FlexLevel(ArcRefCell<FlexLevelBox>),
TableLevelBox(TableLevelBox),
TaffyItemBox(ArcRefCell<TaffyItemBox>),
}
impl LayoutBox {
fn invalidate_cached_fragment(&self) {
match self {
LayoutBox::DisplayContents(..) => {},
LayoutBox::BlockLevel(block_level_box) => {
block_level_box.borrow().invalidate_cached_fragment()
},
LayoutBox::InlineLevel(inline_items) => {
for inline_item in inline_items.iter() {
inline_item.borrow().invalidate_cached_fragment()
}
},
LayoutBox::FlexLevel(flex_level_box) => {
flex_level_box.borrow().invalidate_cached_fragment()
},
LayoutBox::TaffyItemBox(taffy_item_box) => {
taffy_item_box.borrow_mut().invalidate_cached_fragment()
},
LayoutBox::TableLevelBox(table_box) => table_box.invalidate_cached_fragment(),
}
}
pub(crate) fn fragments(&self) -> Vec<Fragment> {
match self {
LayoutBox::DisplayContents(..) => vec![],
LayoutBox::BlockLevel(block_level_box) => block_level_box.borrow().fragments(),
LayoutBox::InlineLevel(inline_items) => inline_items
.iter()
.flat_map(|inline_item| inline_item.borrow().fragments())
.collect(),
LayoutBox::FlexLevel(flex_level_box) => flex_level_box.borrow().fragments(),
LayoutBox::TaffyItemBox(taffy_item_box) => taffy_item_box.borrow().fragments(),
LayoutBox::TableLevelBox(table_box) => table_box.fragments(),
}
}
fn repair_style(
&self,
context: &SharedStyleContext,
node: &ServoLayoutNode,
new_style: &ServoArc<ComputedValues>,
) {
match self {
LayoutBox::DisplayContents(inline_shared_styles) => {
*inline_shared_styles.style.borrow_mut() = new_style.clone();
*inline_shared_styles.selected.borrow_mut() = node.to_threadsafe().selected_style();
},
LayoutBox::BlockLevel(block_level_box) => {
block_level_box
.borrow_mut()
.repair_style(context, node, new_style);
},
LayoutBox::InlineLevel(inline_items) => {
for inline_item in inline_items {
inline_item
.borrow_mut()
.repair_style(context, node, new_style);
}
},
LayoutBox::FlexLevel(flex_level_box) => flex_level_box
.borrow_mut()
.repair_style(context, node, new_style),
LayoutBox::TableLevelBox(table_level_box) => {
table_level_box.repair_style(context, node, new_style)
},
LayoutBox::TaffyItemBox(taffy_item_box) => taffy_item_box
.borrow_mut()
.repair_style(context, node, new_style),
}
}
}
/// A wrapper for [`InnerDOMLayoutData`]. This is necessary to give the entire data
/// structure interior mutability, as we will need to mutate the layout data of
/// non-mutable DOM nodes.
#[derive(Default, MallocSizeOf)]
pub struct DOMLayoutData(AtomicRefCell<InnerDOMLayoutData>);
// The implementation of this trait allows the data to be stored in the DOM.
impl LayoutDataTrait for DOMLayoutData {}
impl GenericLayoutDataTrait for DOMLayoutData {
fn as_any(&self) -> &dyn Any {
self
}
}
pub struct BoxSlot<'dom> {
pub(crate) slot: Option<ArcRefCell<Option<LayoutBox>>>,
pub(crate) marker: PhantomData<&'dom ()>,
}
/// A mutable reference to a `LayoutBox` stored in a DOM element.
impl BoxSlot<'_> {
pub(crate) fn new(slot: ArcRefCell<Option<LayoutBox>>) -> Self {
*slot.borrow_mut() = None;
let slot = Some(slot);
Self {
slot,
marker: PhantomData,
}
}
pub(crate) fn dummy() -> Self {
let slot = None;
Self {
slot,
marker: PhantomData,
}
}
pub(crate) fn set(mut self, box_: LayoutBox) {
if let Some(slot) = &mut self.slot {
*slot.borrow_mut() = Some(box_);
}
}
}
impl Drop for BoxSlot<'_> {
fn drop(&mut self) {
if !std::thread::panicking() {
if let Some(slot) = &mut self.slot {
assert!(slot.borrow().is_some(), "failed to set a layout box");
}
}
}
}
pub(crate) trait NodeExt<'dom> {
/// Returns the image if its loaded, and its size in image pixels
/// adjusted for `image_density`.
fn as_image(&self) -> Option<(Option<Image>, PhysicalSize<f64>)>;
fn as_canvas(&self) -> Option<(CanvasInfo, PhysicalSize<f64>)>;
fn as_iframe(&self) -> Option<(PipelineId, BrowsingContextId)>;
fn as_video(&self) -> Option<(Option<webrender_api::ImageKey>, Option<PhysicalSize<f64>>)>;
fn as_typeless_object_with_data_attribute(&self) -> Option<String>;
fn style(&self, context: &SharedStyleContext) -> ServoArc<ComputedValues>;
fn layout_data_mut(&self) -> AtomicRefMut<'dom, InnerDOMLayoutData>;
fn layout_data(&self) -> Option<AtomicRef<'dom, InnerDOMLayoutData>>;
fn element_box_slot(&self) -> BoxSlot<'dom>;
fn pseudo_element_box_slot(&self, which: PseudoElement) -> BoxSlot<'dom>;
fn unset_pseudo_element_box(&self, which: PseudoElement);
/// Remove boxes for the element itself, and its `:before` and `:after` if any.
fn unset_all_boxes(&self);
fn fragments_for_pseudo(&self, pseudo_element: Option<PseudoElement>) -> Vec<Fragment>;
fn invalidate_cached_fragment(&self);
fn repair_style(&self, context: &SharedStyleContext);
}
impl<'dom> NodeExt<'dom> for ServoLayoutNode<'dom> {
fn as_image(&self) -> Option<(Option<Image>, PhysicalSize<f64>)> {
let node = self.to_threadsafe();
let (resource, metadata) = node.image_data()?;
let (width, height) = resource
.as_ref()
.map(|image| {
let image_metadata = image.metadata();
(image_metadata.width, image_metadata.height)
})
.or_else(|| metadata.map(|metadata| (metadata.width, metadata.height)))
.unwrap_or((0, 0));
let (mut width, mut height) = (width as f64, height as f64);
if let Some(density) = node.image_density().filter(|density| *density != 1.) {
width /= density;
height /= density;
}
Some((resource, PhysicalSize::new(width, height)))
}
fn as_video(&self) -> Option<(Option<webrender_api::ImageKey>, Option<PhysicalSize<f64>>)> {
let node = self.to_threadsafe();
let data = node.media_data()?;
let natural_size = if let Some(frame) = data.current_frame {
Some(PhysicalSize::new(frame.width.into(), frame.height.into()))
} else {
data.metadata
.map(|meta| PhysicalSize::new(meta.width.into(), meta.height.into()))
};
Some((
data.current_frame.map(|frame| frame.image_key),
natural_size,
))
}
fn as_canvas(&self) -> Option<(CanvasInfo, PhysicalSize<f64>)> {
let node = self.to_threadsafe();
let canvas_data = node.canvas_data()?;
let source = canvas_data.source;
Some((
CanvasInfo { source },
PhysicalSize::new(canvas_data.width.into(), canvas_data.height.into()),
))
}
fn as_iframe(&self) -> Option<(PipelineId, BrowsingContextId)> {
let node = self.to_threadsafe();
match (node.iframe_pipeline_id(), node.iframe_browsing_context_id()) {
(Some(pipeline_id), Some(browsing_context_id)) => {
Some((pipeline_id, browsing_context_id))
},
_ => None,
}
}
fn as_typeless_object_with_data_attribute(&self) -> Option<String> {
if LayoutNode::type_id(self) !=
ScriptLayoutNodeType::Element(LayoutElementType::HTMLObjectElement)
{
return None;
}
// TODO: This is the what the legacy layout system did, but really if Servo
// supports any `<object>` that's an image, it should support those with URLs
// and `type` attributes with image mime types.
let element = self.to_threadsafe().as_element()?;
if element.get_attr(&ns!(), &local_name!("type")).is_some() {
return None;
}
element
.get_attr(&ns!(), &local_name!("data"))
.map(|string| string.to_owned())
}
fn style(&self, context: &SharedStyleContext) -> ServoArc<ComputedValues> {
self.to_threadsafe().style(context)
}
fn layout_data_mut(&self) -> AtomicRefMut<'dom, InnerDOMLayoutData> {
if LayoutNode::layout_data(self).is_none() {
self.initialize_layout_data::<DOMLayoutData>();
}
LayoutNode::layout_data(self)
.unwrap()
.as_any()
.downcast_ref::<DOMLayoutData>()
.unwrap()
.0
.borrow_mut()
}
fn layout_data(&self) -> Option<AtomicRef<'dom, InnerDOMLayoutData>> {
LayoutNode::layout_data(self).map(|data| {
data.as_any()
.downcast_ref::<DOMLayoutData>()
.unwrap()
.0
.borrow()
})
}
fn element_box_slot(&self) -> BoxSlot<'dom> {
BoxSlot::new(self.layout_data_mut().self_box.clone())
}
fn pseudo_element_box_slot(&self, pseudo_element_type: PseudoElement) -> BoxSlot<'dom> {
let data = self.layout_data_mut();
let cell = match pseudo_element_type {
PseudoElement::Before => &data.pseudo_before_box,
PseudoElement::After => &data.pseudo_after_box,
PseudoElement::Marker => &data.pseudo_marker_box,
_ => unreachable!(
"Asked for box slot for unsupported pseudo-element: {:?}",
pseudo_element_type
),
};
BoxSlot::new(cell.clone())
}
fn unset_pseudo_element_box(&self, pseudo_element_type: PseudoElement) {
let data = self.layout_data_mut();
let cell = match pseudo_element_type {
PseudoElement::Before => &data.pseudo_before_box,
PseudoElement::After => &data.pseudo_after_box,
PseudoElement::Marker => &data.pseudo_marker_box,
_ => unreachable!(
"Asked for box slot for unsupported pseudo-element: {:?}",
pseudo_element_type
),
};
*cell.borrow_mut() = None;
}
fn unset_all_boxes(&self) {
let data = self.layout_data_mut();
*data.self_box.borrow_mut() = None;
*data.pseudo_before_box.borrow_mut() = None;
*data.pseudo_after_box.borrow_mut() = None;
*data.pseudo_marker_box.borrow_mut() = None;
// Stylo already takes care of removing all layout data
// for DOM descendants of elements with `display: none`.
}
fn invalidate_cached_fragment(&self) {
let data = self.layout_data_mut();
if let Some(data) = data.self_box.borrow_mut().as_mut() {
data.invalidate_cached_fragment();
}
}
fn fragments_for_pseudo(&self, pseudo_element: Option<PseudoElement>) -> Vec<Fragment> {
NodeExt::layout_data(self)
.and_then(|layout_data| {
layout_data
.for_pseudo(pseudo_element)
.as_ref()
.map(LayoutBox::fragments)
})
.unwrap_or_default()
}
fn repair_style(&self, context: &SharedStyleContext) {
let data = self.layout_data_mut();
if let Some(layout_object) = &*data.self_box.borrow() {
let style = self.to_threadsafe().style(context);
layout_object.repair_style(context, self, &style);
}
if let Some(layout_object) = &*data.pseudo_before_box.borrow() {
if let Some(node) = self.to_threadsafe().with_pseudo(PseudoElement::Before) {
layout_object.repair_style(context, self, &node.style(context));
}
}
if let Some(layout_object) = &*data.pseudo_after_box.borrow() {
if let Some(node) = self.to_threadsafe().with_pseudo(PseudoElement::After) {
layout_object.repair_style(context, self, &node.style(context));
}
}
if let Some(layout_object) = &*data.pseudo_marker_box.borrow() {
if let Some(node) = self.to_threadsafe().with_pseudo(PseudoElement::Marker) {
layout_object.repair_style(context, self, &node.style(context));
}
}
}
}