servo/components/layout_2020/flexbox.rs
Anthony Ramine e975d24c4b Store abspos boxes in a RefCell too
We want to mutate them when lazily computing their content sizes, but they
are behind an Arc for the hoisting infra, so it also needs its own layer
of inner mutability.
2020-06-09 15:13:18 +02:00

252 lines
8.9 KiB
Rust

/* 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 crate::cell::ArcRefCell;
use crate::context::LayoutContext;
use crate::dom_traversal::{
BoxSlot, Contents, NodeAndStyleInfo, NodeExt, NonReplacedContents, TraversalHandler,
};
use crate::element_data::LayoutBox;
use crate::formatting_contexts::{IndependentFormattingContext, IndependentLayout};
use crate::fragments::Tag;
use crate::positioned::{AbsolutelyPositionedBox, PositioningContext};
use crate::sizing::{BoxContentSizes, ContentSizes, ContentSizesRequest};
use crate::style_ext::DisplayGeneratingBox;
use crate::ContainingBlock;
use rayon::iter::{IntoParallelIterator, ParallelIterator};
use std::borrow::Cow;
use style::values::computed::Length;
use style::values::specified::text::TextDecorationLine;
use style::Zero;
// FIXME: `min-width: auto` is not zero: https://drafts.csswg.org/css-flexbox/#min-size-auto
#[derive(Debug, Serialize)]
pub(crate) struct FlexContainer {
children: Vec<ArcRefCell<FlexLevelBox>>,
}
#[derive(Debug, Serialize)]
pub(crate) enum FlexLevelBox {
FlexItem(IndependentFormattingContext),
OutOfFlowAbsolutelyPositionedBox(ArcRefCell<AbsolutelyPositionedBox>),
}
impl FlexContainer {
pub fn construct<'dom>(
context: &LayoutContext,
info: &NodeAndStyleInfo<impl NodeExt<'dom>>,
contents: NonReplacedContents,
content_sizes: ContentSizesRequest,
propagated_text_decoration_line: TextDecorationLine,
) -> (Self, BoxContentSizes) {
let text_decoration_line =
propagated_text_decoration_line | info.style.clone_text_decoration_line();
let mut builder = FlexContainerBuilder {
context,
info,
text_decoration_line,
contiguous_text_runs: Vec::new(),
jobs: Vec::new(),
has_text_runs: false,
};
contents.traverse(context, info, &mut builder);
let content_sizes = content_sizes.compute(|| {
// FIXME
ContentSizes::zero()
});
(builder.finish(), content_sizes)
}
}
/// https://drafts.csswg.org/css-flexbox/#flex-items
struct FlexContainerBuilder<'a, 'dom, Node> {
context: &'a LayoutContext<'a>,
info: &'a NodeAndStyleInfo<Node>,
text_decoration_line: TextDecorationLine,
contiguous_text_runs: Vec<TextRun<'dom, Node>>,
/// To be run in parallel with rayon in `finish`
jobs: Vec<FlexLevelJob<'dom, Node>>,
has_text_runs: bool,
}
enum FlexLevelJob<'dom, Node> {
/// Or pseudo-element
Element {
info: NodeAndStyleInfo<Node>,
display: DisplayGeneratingBox,
contents: Contents,
box_slot: BoxSlot<'dom>,
},
TextRuns(Vec<TextRun<'dom, Node>>),
}
struct TextRun<'dom, Node> {
info: NodeAndStyleInfo<Node>,
text: Cow<'dom, str>,
}
impl<'a, 'dom, Node: 'dom> TraversalHandler<'dom, Node> for FlexContainerBuilder<'a, 'dom, Node>
where
Node: NodeExt<'dom>,
{
fn handle_text(&mut self, info: &NodeAndStyleInfo<Node>, text: Cow<'dom, str>) {
self.contiguous_text_runs.push(TextRun {
info: info.clone(),
text,
})
}
/// Or pseudo-element
fn handle_element(
&mut self,
info: &NodeAndStyleInfo<Node>,
display: DisplayGeneratingBox,
contents: Contents,
box_slot: BoxSlot<'dom>,
) {
// FIXME: are text runs considered "contiguous" if they are only separated
// by an out-of-flow abspos element?
// (That is, are they wrapped in the same anonymous flex item, or each its own?)
self.wrap_any_text_in_anonymous_block_container();
self.jobs.push(FlexLevelJob::Element {
info: info.clone(),
display,
contents,
box_slot,
})
}
}
/// https://drafts.csswg.org/css-text/#white-space
fn is_only_document_white_space<Node>(run: &TextRun<'_, Node>) -> bool {
// FIXME: is this the right definition? See
// https://github.com/w3c/csswg-drafts/issues/5146
// https://github.com/w3c/csswg-drafts/issues/5147
run.text
.bytes()
.all(|byte| matches!(byte, b' ' | b'\n' | b'\t'))
}
impl<'a, 'dom, Node: 'dom> FlexContainerBuilder<'a, 'dom, Node>
where
Node: NodeExt<'dom>,
{
fn wrap_any_text_in_anonymous_block_container(&mut self) {
let runs = std::mem::take(&mut self.contiguous_text_runs);
if runs.iter().all(is_only_document_white_space) {
// There is no text run, or they all only contain document white space characters
} else {
self.jobs.push(FlexLevelJob::TextRuns(runs));
self.has_text_runs = true;
}
}
fn finish(mut self) -> FlexContainer {
self.wrap_any_text_in_anonymous_block_container();
let anonymous_style = if self.has_text_runs {
Some(
self.context
.shared_context()
.stylist
.style_for_anonymous::<Node::ConcreteElement>(
&self.context.shared_context().guards,
&style::selector_parser::PseudoElement::ServoText,
&self.info.style,
),
)
} else {
None
};
let mut children = std::mem::take(&mut self.jobs)
.into_par_iter()
.map(|job| match job {
FlexLevelJob::TextRuns(runs) => ArcRefCell::new(FlexLevelBox::FlexItem(
IndependentFormattingContext::construct_for_text_runs(
self.context,
&self
.info
.new_replacing_style(anonymous_style.clone().unwrap()),
runs.into_iter().map(|run| crate::flow::inline::TextRun {
tag: Tag::from_node_and_style_info(&run.info),
text: run.text.into(),
parent_style: run.info.style,
}),
ContentSizesRequest::None, // FIXME: request sizes when we start using them
self.text_decoration_line,
),
)),
FlexLevelJob::Element {
info,
display,
contents,
box_slot,
} => {
let display_inside = match display {
DisplayGeneratingBox::OutsideInside { inside, .. } => inside,
};
let box_ = if info.style.get_box().position.is_absolutely_positioned() {
// https://drafts.csswg.org/css-flexbox/#abspos-items
ArcRefCell::new(FlexLevelBox::OutOfFlowAbsolutelyPositionedBox(
ArcRefCell::new(AbsolutelyPositionedBox::construct(
self.context,
&info,
display_inside,
contents,
)),
))
} else {
ArcRefCell::new(FlexLevelBox::FlexItem(
IndependentFormattingContext::construct(
self.context,
&info,
display_inside,
contents,
ContentSizesRequest::None, // FIXME: request sizes when we start using them
self.text_decoration_line,
),
))
};
box_slot.set(LayoutBox::FlexLevel(box_.clone()));
box_
},
})
.collect::<Vec<_>>();
// https://drafts.csswg.org/css-flexbox/#order-modified-document-order
children.sort_by_key(|child| match &*child.borrow() {
FlexLevelBox::FlexItem(item) => item.style.clone_order(),
// “Absolutely-positioned children of a flex container are treated
// as having order: 0 for the purpose of determining their painting order
// relative to flex items.”
FlexLevelBox::OutOfFlowAbsolutelyPositionedBox(_) => 0,
});
FlexContainer { children }
}
}
impl FlexContainer {
pub(crate) fn layout(
&self,
layout_context: &LayoutContext,
positioning_context: &mut PositioningContext,
containing_block: &ContainingBlock,
tree_rank: usize,
) -> IndependentLayout {
// FIXME
let _ = layout_context;
let _ = positioning_context;
let _ = containing_block;
let _ = tree_rank;
IndependentLayout {
fragments: Vec::new(),
content_block_size: Length::zero(),
}
}
}