mirror of
https://github.com/servo/servo.git
synced 2025-06-06 16:45:39 +00:00
2b63e60e8f
This change adds support for the `::marker` pseudo-element and ensure that markers are cached into the box tree. This is only initial support, there are a few things missing such as animations, transitions, and support the `content` CSS property. Testing: There are WPT tests for this change. Signed-off-by: Martin Robinson <mrobinson@igalia.com> Signed-off-by: Martin Robinson <mrobinson@igalia.com>
554 lines
20 KiB
Rust
554 lines
20 KiB
Rust
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at https://mozilla.org/MPL/2.0/. */
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use std::borrow::Cow;
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use std::iter::FusedIterator;
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use html5ever::{LocalName, local_name};
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use script_layout_interface::wrapper_traits::{ThreadSafeLayoutElement, ThreadSafeLayoutNode};
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use script_layout_interface::{LayoutElementType, LayoutNodeType};
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use selectors::Element as SelectorsElement;
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use servo_arc::Arc as ServoArc;
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use style::dom::{TElement, TShadowRoot};
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use style::properties::ComputedValues;
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use style::selector_parser::PseudoElement;
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use style::values::generics::counters::{Content, ContentItem};
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use style::values::specified::Quotes;
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use crate::context::LayoutContext;
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use crate::dom::{BoxSlot, LayoutBox, NodeExt};
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use crate::fragment_tree::{BaseFragmentInfo, FragmentFlags, Tag};
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use crate::quotes::quotes_for_lang;
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use crate::replaced::ReplacedContents;
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use crate::style_ext::{Display, DisplayGeneratingBox, DisplayInside, DisplayOutside};
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/// A data structure used to pass and store related layout information together to
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/// avoid having to repeat the same arguments in argument lists.
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#[derive(Clone)]
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pub(crate) struct NodeAndStyleInfo<Node> {
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pub node: Node,
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pub pseudo_element_type: Option<PseudoElement>,
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pub style: ServoArc<ComputedValues>,
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}
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impl<'dom, Node: NodeExt<'dom>> NodeAndStyleInfo<Node> {
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fn new_with_pseudo(
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node: Node,
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pseudo_element_type: PseudoElement,
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style: ServoArc<ComputedValues>,
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) -> Self {
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Self {
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node,
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pseudo_element_type: Some(pseudo_element_type),
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style,
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}
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}
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pub(crate) fn new(node: Node, style: ServoArc<ComputedValues>) -> Self {
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Self {
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node,
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pseudo_element_type: None,
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style,
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}
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}
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pub(crate) fn is_single_line_text_input(&self) -> bool {
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self.node.type_id() == LayoutNodeType::Element(LayoutElementType::HTMLInputElement)
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}
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pub(crate) fn pseudo(
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&self,
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context: &LayoutContext,
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pseudo_element_type: PseudoElement,
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) -> Option<Self> {
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let style = self
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.node
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.to_threadsafe()
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.as_element()?
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.with_pseudo(pseudo_element_type)?
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.style(context.shared_context());
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Some(NodeAndStyleInfo {
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node: self.node,
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pseudo_element_type: Some(pseudo_element_type),
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style,
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})
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}
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}
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impl<'dom, Node> From<&NodeAndStyleInfo<Node>> for BaseFragmentInfo
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where
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Node: NodeExt<'dom>,
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{
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fn from(info: &NodeAndStyleInfo<Node>) -> Self {
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let node = info.node;
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let pseudo = info.pseudo_element_type;
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let threadsafe_node = node.to_threadsafe();
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let mut flags = FragmentFlags::empty();
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// Anonymous boxes should not have a tag, because they should not take part in hit testing.
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//
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// TODO(mrobinson): It seems that anonymous boxes should take part in hit testing in some
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// cases, but currently this means that the order of hit test results isn't as expected for
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// some WPT tests. This needs more investigation.
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if matches!(
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pseudo,
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Some(PseudoElement::ServoAnonymousBox) |
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Some(PseudoElement::ServoAnonymousTable) |
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Some(PseudoElement::ServoAnonymousTableCell) |
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Some(PseudoElement::ServoAnonymousTableRow)
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) {
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return Self::anonymous();
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}
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if let Some(element) = threadsafe_node.as_html_element() {
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if element.is_body_element_of_html_element_root() {
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flags.insert(FragmentFlags::IS_BODY_ELEMENT_OF_HTML_ELEMENT_ROOT);
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}
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match element.get_local_name() {
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&local_name!("br") => {
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flags.insert(FragmentFlags::IS_BR_ELEMENT);
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},
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&local_name!("table") | &local_name!("th") | &local_name!("td") => {
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flags.insert(FragmentFlags::IS_TABLE_TH_OR_TD_ELEMENT);
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},
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_ => {},
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}
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if matches!(
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element.type_id(),
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Some(LayoutNodeType::Element(
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LayoutElementType::HTMLInputElement | LayoutElementType::HTMLTextAreaElement
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))
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) {
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flags.insert(FragmentFlags::IS_TEXT_CONTROL);
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}
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if ThreadSafeLayoutElement::is_root(&element) {
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flags.insert(FragmentFlags::IS_ROOT_ELEMENT);
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}
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};
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Self {
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tag: Some(Tag::new_pseudo(threadsafe_node.opaque(), pseudo)),
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flags,
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}
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}
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}
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#[derive(Debug)]
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pub(super) enum Contents {
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/// Any kind of content that is not replaced, including the contents of pseudo-elements.
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NonReplaced(NonReplacedContents),
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/// Example: an `<img src=…>` element.
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/// <https://drafts.csswg.org/css2/conform.html#replaced-element>
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Replaced(ReplacedContents),
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}
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#[derive(Debug)]
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#[allow(clippy::enum_variant_names)]
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pub(super) enum NonReplacedContents {
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/// Refers to a DOM subtree, plus `::before` and `::after` pseudo-elements.
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OfElement,
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/// Content of a `::before` or `::after` pseudo-element that is being generated.
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/// <https://drafts.csswg.org/css2/generate.html#content>
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OfPseudoElement(Vec<PseudoElementContentItem>),
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/// Workaround for input and textarea element until we properly implement `display-inside`.
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OfTextControl,
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}
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#[derive(Debug)]
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pub(super) enum PseudoElementContentItem {
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Text(String),
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Replaced(ReplacedContents),
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}
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pub(super) trait TraversalHandler<'dom, Node>
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where
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Node: 'dom,
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{
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fn handle_text(&mut self, info: &NodeAndStyleInfo<Node>, text: Cow<'dom, str>);
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/// Or pseudo-element
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fn handle_element(
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&mut self,
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info: &NodeAndStyleInfo<Node>,
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display: DisplayGeneratingBox,
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contents: Contents,
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box_slot: BoxSlot<'dom>,
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);
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}
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fn traverse_children_of<'dom, Node>(
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parent_element: Node,
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context: &LayoutContext,
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handler: &mut impl TraversalHandler<'dom, Node>,
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) where
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Node: NodeExt<'dom>,
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{
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traverse_eager_pseudo_element(PseudoElement::Before, parent_element, context, handler);
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let is_text_input_element = matches!(
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parent_element.type_id(),
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LayoutNodeType::Element(LayoutElementType::HTMLInputElement)
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);
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let is_textarea_element = matches!(
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parent_element.type_id(),
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LayoutNodeType::Element(LayoutElementType::HTMLTextAreaElement)
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);
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if is_text_input_element || is_textarea_element {
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let info = NodeAndStyleInfo::new(parent_element, parent_element.style(context));
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if is_text_input_element {
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// The addition of zero-width space here forces the text input to have an inline formatting
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// context that might otherwise be trimmed if there's no text. This is important to ensure
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// that the input element is at least as tall as the line gap of the caret:
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// <https://drafts.csswg.org/css-ui/#element-with-default-preferred-size>.
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//
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// TODO: Is there a less hacky way to do this?
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handler.handle_text(&info, "\u{200B}".into());
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}
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handler.handle_text(&info, parent_element.to_threadsafe().node_text_content());
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}
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if !is_text_input_element && !is_textarea_element {
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for child in iter_child_nodes(parent_element) {
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if child.is_text_node() {
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let info = NodeAndStyleInfo::new(child, child.style(context));
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handler.handle_text(&info, child.to_threadsafe().node_text_content());
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} else if child.is_element() {
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traverse_element(child, context, handler);
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}
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}
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}
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traverse_eager_pseudo_element(PseudoElement::After, parent_element, context, handler);
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}
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fn traverse_element<'dom, Node>(
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element: Node,
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context: &LayoutContext,
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handler: &mut impl TraversalHandler<'dom, Node>,
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) where
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Node: NodeExt<'dom>,
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{
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// Clear any existing pseudo-element box slot, because markers are not handled like
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// `::before`` and `::after`. They are processed during box tree creation.
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element.unset_pseudo_element_box(PseudoElement::Marker);
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let replaced = ReplacedContents::for_element(element, context);
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let style = element.style(context);
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match Display::from(style.get_box().display) {
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Display::None => element.unset_all_boxes(),
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Display::Contents => {
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if replaced.is_some() {
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// `display: content` on a replaced element computes to `display: none`
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// <https://drafts.csswg.org/css-display-3/#valdef-display-contents>
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element.unset_all_boxes()
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} else {
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element.element_box_slot().set(LayoutBox::DisplayContents);
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traverse_children_of(element, context, handler)
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}
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},
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Display::GeneratingBox(display) => {
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let contents = if let Some(replaced) = replaced {
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Contents::Replaced(replaced)
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} else if matches!(
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element.type_id(),
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LayoutNodeType::Element(
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LayoutElementType::HTMLInputElement | LayoutElementType::HTMLTextAreaElement
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)
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) {
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NonReplacedContents::OfTextControl.into()
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} else {
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NonReplacedContents::OfElement.into()
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};
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let display = display.used_value_for_contents(&contents);
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let box_slot = element.element_box_slot();
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let info = NodeAndStyleInfo::new(element, style);
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handler.handle_element(&info, display, contents, box_slot);
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},
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}
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}
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fn traverse_eager_pseudo_element<'dom, Node>(
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pseudo_element_type: PseudoElement,
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node: Node,
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context: &LayoutContext,
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handler: &mut impl TraversalHandler<'dom, Node>,
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) where
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Node: NodeExt<'dom>,
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{
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assert!(pseudo_element_type.is_eager());
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// First clear any old contents from the node.
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node.unset_pseudo_element_box(pseudo_element_type);
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let Some(element) = node.to_threadsafe().as_element() else {
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return;
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};
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let Some(pseudo_element) = element.with_pseudo(pseudo_element_type) else {
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return;
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};
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let style = pseudo_element.style(context.shared_context());
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if style.ineffective_content_property() {
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return;
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}
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let info = NodeAndStyleInfo::new_with_pseudo(node, pseudo_element_type, style);
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match Display::from(info.style.get_box().display) {
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Display::None => {},
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Display::Contents => {
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let items = generate_pseudo_element_content(&info.style, node, context);
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let box_slot = node.pseudo_element_box_slot(pseudo_element_type);
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box_slot.set(LayoutBox::DisplayContents);
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traverse_pseudo_element_contents(&info, context, handler, items);
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},
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Display::GeneratingBox(display) => {
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let items = generate_pseudo_element_content(&info.style, node, context);
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let box_slot = node.pseudo_element_box_slot(pseudo_element_type);
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let contents = NonReplacedContents::OfPseudoElement(items).into();
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handler.handle_element(&info, display, contents, box_slot);
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},
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}
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}
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fn traverse_pseudo_element_contents<'dom, Node>(
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info: &NodeAndStyleInfo<Node>,
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context: &LayoutContext,
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handler: &mut impl TraversalHandler<'dom, Node>,
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items: Vec<PseudoElementContentItem>,
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) where
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Node: NodeExt<'dom>,
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{
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let mut anonymous_info = None;
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for item in items {
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match item {
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PseudoElementContentItem::Text(text) => handler.handle_text(info, text.into()),
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PseudoElementContentItem::Replaced(contents) => {
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let anonymous_info = anonymous_info.get_or_insert_with(|| {
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info.pseudo(context, PseudoElement::ServoAnonymousBox)
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.unwrap_or_else(|| info.clone())
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});
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let display_inline = DisplayGeneratingBox::OutsideInside {
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outside: DisplayOutside::Inline,
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inside: DisplayInside::Flow {
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is_list_item: false,
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},
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};
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// `display` is not inherited, so we get the initial value
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debug_assert!(
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Display::from(anonymous_info.style.get_box().display) ==
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Display::GeneratingBox(display_inline)
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);
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handler.handle_element(
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anonymous_info,
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display_inline,
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Contents::Replaced(contents),
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// We don’t keep pointers to boxes generated by contents of pseudo-elements
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BoxSlot::dummy(),
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)
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},
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}
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}
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}
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impl Contents {
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/// Returns true iff the `try_from` impl below would return `Err(_)`
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pub fn is_replaced(&self) -> bool {
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matches!(self, Contents::Replaced(_))
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}
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}
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impl From<NonReplacedContents> for Contents {
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fn from(non_replaced_contents: NonReplacedContents) -> Self {
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Contents::NonReplaced(non_replaced_contents)
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}
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}
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impl std::convert::TryFrom<Contents> for NonReplacedContents {
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type Error = &'static str;
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fn try_from(contents: Contents) -> Result<Self, Self::Error> {
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match contents {
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Contents::NonReplaced(non_replaced_contents) => Ok(non_replaced_contents),
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Contents::Replaced(_) => {
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Err("Tried to covnert a `Contents::Replaced` into `NonReplacedContent`")
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},
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}
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}
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}
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impl NonReplacedContents {
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pub(crate) fn traverse<'dom, Node>(
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self,
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context: &LayoutContext,
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info: &NodeAndStyleInfo<Node>,
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handler: &mut impl TraversalHandler<'dom, Node>,
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) where
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Node: NodeExt<'dom>,
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{
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match self {
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NonReplacedContents::OfElement | NonReplacedContents::OfTextControl => {
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traverse_children_of(info.node, context, handler)
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},
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NonReplacedContents::OfPseudoElement(items) => {
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traverse_pseudo_element_contents(info, context, handler, items)
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},
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}
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}
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}
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fn get_quote_from_pair<I, S>(item: &ContentItem<I>, opening: &S, closing: &S) -> String
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where
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S: ToString + ?Sized,
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{
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match item {
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ContentItem::OpenQuote => opening.to_string(),
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ContentItem::CloseQuote => closing.to_string(),
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_ => unreachable!("Got an unexpected ContentItem type when processing quotes."),
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}
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}
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/// <https://www.w3.org/TR/CSS2/generate.html#propdef-content>
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fn generate_pseudo_element_content<'dom, Node>(
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pseudo_element_style: &ComputedValues,
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element: Node,
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context: &LayoutContext,
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) -> Vec<PseudoElementContentItem>
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where
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Node: NodeExt<'dom>,
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{
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match &pseudo_element_style.get_counters().content {
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Content::Items(items) => {
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let mut vec = vec![];
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for item in items.items.iter() {
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match item {
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ContentItem::String(s) => {
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vec.push(PseudoElementContentItem::Text(s.to_string()));
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},
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ContentItem::Attr(attr) => {
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let element = element
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.to_threadsafe()
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.as_element()
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.expect("Expected an element");
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// From
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// <https://html.spec.whatwg.org/multipage/#case-sensitivity-of-the-css-%27attr%28%29%27-function>
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//
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// > CSS Values and Units leaves the case-sensitivity of attribute names for
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// > the purpose of the `attr()` function to be defined by the host language.
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// > [[CSSVALUES]].
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// >
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// > When comparing the attribute name part of a CSS `attr()`function to the
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// > names of namespace-less attributes on HTML elements in HTML documents,
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// > the name part of the CSS `attr()` function must first be converted to
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// > ASCII lowercase. The same function when compared to other attributes must
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// > be compared according to its original case. In both cases, to match the
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// > values must be identical to each other (and therefore the comparison is
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// > case sensitive).
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let attr_name = match element.is_html_element_in_html_document() {
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true => &*attr.attribute.to_ascii_lowercase(),
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false => &*attr.attribute,
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};
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let attr_val =
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element.get_attr(&attr.namespace_url, &LocalName::from(attr_name));
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vec.push(PseudoElementContentItem::Text(
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attr_val.map_or("".to_string(), |s| s.to_string()),
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));
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},
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ContentItem::Image(image) => {
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if let Some(replaced_content) =
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ReplacedContents::from_image(element, context, image)
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{
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vec.push(PseudoElementContentItem::Replaced(replaced_content));
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}
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},
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ContentItem::OpenQuote | ContentItem::CloseQuote => {
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// TODO(xiaochengh): calculate quote depth
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let maybe_quote = match &pseudo_element_style.get_list().quotes {
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Quotes::QuoteList(quote_list) => {
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quote_list.0.first().map(|quote_pair| {
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get_quote_from_pair(
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item,
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&*quote_pair.opening,
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&*quote_pair.closing,
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)
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})
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},
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Quotes::Auto => {
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let lang = &pseudo_element_style.get_font()._x_lang;
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let quotes = quotes_for_lang(lang.0.as_ref(), 0);
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Some(get_quote_from_pair(item, "es.opening, "es.closing))
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},
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};
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if let Some(quote) = maybe_quote {
|
||
vec.push(PseudoElementContentItem::Text(quote));
|
||
}
|
||
},
|
||
ContentItem::Counter(_, _) |
|
||
ContentItem::Counters(_, _, _) |
|
||
ContentItem::NoOpenQuote |
|
||
ContentItem::NoCloseQuote => {
|
||
// TODO: Add support for counters and quotes.
|
||
},
|
||
}
|
||
}
|
||
vec
|
||
},
|
||
Content::Normal | Content::None => unreachable!(),
|
||
}
|
||
}
|
||
|
||
pub enum ChildNodeIterator<Node> {
|
||
/// Iterating over the children of a node
|
||
Node(Option<Node>),
|
||
/// Iterating over the assigned nodes of a `HTMLSlotElement`
|
||
Slottables(<Vec<Node> as IntoIterator>::IntoIter),
|
||
}
|
||
|
||
#[allow(clippy::unnecessary_to_owned)] // Clippy is wrong.
|
||
pub(crate) fn iter_child_nodes<'dom, Node>(parent: Node) -> ChildNodeIterator<Node>
|
||
where
|
||
Node: NodeExt<'dom>,
|
||
{
|
||
if let Some(element) = parent.as_element() {
|
||
if let Some(shadow) = element.shadow_root() {
|
||
return iter_child_nodes(shadow.as_node());
|
||
};
|
||
|
||
let slotted_nodes = element.slotted_nodes();
|
||
if !slotted_nodes.is_empty() {
|
||
return ChildNodeIterator::Slottables(slotted_nodes.to_owned().into_iter());
|
||
}
|
||
}
|
||
|
||
let first = parent.first_child();
|
||
ChildNodeIterator::Node(first)
|
||
}
|
||
|
||
impl<'dom, Node> Iterator for ChildNodeIterator<Node>
|
||
where
|
||
Node: NodeExt<'dom>,
|
||
{
|
||
type Item = Node;
|
||
|
||
fn next(&mut self) -> Option<Self::Item> {
|
||
match self {
|
||
Self::Node(node) => {
|
||
let old = *node;
|
||
*node = old?.next_sibling();
|
||
old
|
||
},
|
||
Self::Slottables(slots) => slots.next(),
|
||
}
|
||
}
|
||
}
|
||
|
||
impl<'dom, Node> FusedIterator for ChildNodeIterator<Node> where Node: NodeExt<'dom> {}
|