Auto merge of #26477 - mrobinson:layout-2020-get-computed-value, r=jdm

Add support for getComputedStyle() to layout_2020

These changes add support for `getComputedStyle()` to layout_2020.

---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `___` with appropriate data: -->
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] There are tests for these changes

<!-- Also, please make sure that "Allow edits from maintainers" checkbox is checked, so that we can help you if you get stuck somewhere along the way.-->

<!-- Pull requests that do not address these steps are welcome, but they will require additional verification as part of the review process. -->
This commit is contained in:
bors-servo 2020-05-11 15:57:25 -04:00 committed by GitHub
commit aa9f16ce45
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
188 changed files with 16312 additions and 15198 deletions

View file

@ -237,7 +237,7 @@ impl FragmentTreeRoot {
))
}
fn find<T>(
pub(crate) fn find<T>(
&self,
mut process_func: impl FnMut(&Fragment, &PhysicalRect<Length>) -> Option<T>,
) -> Option<T> {
@ -251,16 +251,18 @@ impl FragmentTreeRoot {
pub fn get_content_box_for_node(&self, requested_node: OpaqueNode) -> Rect<Au> {
let mut bounding_box = PhysicalRect::zero();
self.find(|fragment, containing_block| {
if fragment.tag() != Some(requested_node) {
return None::<()>;
}
let fragment_relative_rect = match fragment {
Fragment::Box(fragment) if fragment.tag == requested_node => fragment
Fragment::Box(fragment) => fragment
.border_rect()
.to_physical(fragment.style.writing_mode, &containing_block),
Fragment::AbsoluteOrFixedPositioned(_) => PhysicalRect::zero(),
Fragment::Text(fragment) if fragment.tag == requested_node => fragment
Fragment::Text(fragment) => fragment
.rect
.to_physical(fragment.parent_style.writing_mode, &containing_block),
Fragment::Box(_) |
Fragment::Text(_) |
Fragment::AbsoluteOrFixedPositioned(_) |
Fragment::Image(_) |
Fragment::Anonymous(_) => return None,
};

View file

@ -148,6 +148,16 @@ impl Fragment {
position.inline += *offset;
}
pub fn tag(&self) -> Option<OpaqueNode> {
match self {
Fragment::Box(fragment) => Some(fragment.tag),
Fragment::Text(fragment) => Some(fragment.tag),
Fragment::AbsoluteOrFixedPositioned(_) |
Fragment::Anonymous(_) |
Fragment::Image(_) => None,
}
}
pub fn print(&self, tree: &mut PrintTree) {
match self {
Fragment::Box(fragment) => fragment.print(tree),

View file

@ -4,6 +4,8 @@
#![deny(unsafe_code)]
#[macro_use]
extern crate log;
#[macro_use]
extern crate serde;

View file

@ -3,9 +3,9 @@
* file, You can obtain one at https://mozilla.org/MPL/2.0/. */
//! Utilities for querying the layout, as needed by the layout thread.
use crate::context::LayoutContext;
use crate::flow::FragmentTreeRoot;
use crate::fragments::Fragment;
use app_units::Au;
use euclid::default::{Point2D, Rect};
use euclid::Size2D;
@ -16,15 +16,24 @@ use script_layout_interface::rpc::TextIndexResponse;
use script_layout_interface::rpc::{ContentBoxResponse, ContentBoxesResponse, LayoutRPC};
use script_layout_interface::rpc::{NodeGeometryResponse, NodeScrollIdResponse};
use script_layout_interface::rpc::{OffsetParentResponse, ResolvedStyleResponse};
use script_layout_interface::wrapper_traits::{LayoutNode, ThreadSafeLayoutNode};
use script_layout_interface::wrapper_traits::{
LayoutNode, ThreadSafeLayoutElement, ThreadSafeLayoutNode,
};
use script_traits::LayoutMsg as ConstellationMsg;
use script_traits::UntrustedNodeAddress;
use std::collections::HashMap;
use std::sync::{Arc, Mutex};
use style::computed_values::position::T as Position;
use style::context::{StyleContext, ThreadLocalStyleContext};
use style::dom::OpaqueNode;
use style::properties::PropertyId;
use style::dom::TElement;
use style::properties::{LonghandId, PropertyDeclarationId, PropertyId};
use style::selector_parser::PseudoElement;
use style::stylist::RuleInclusion;
use style::traversal::resolve_style;
use style::values::generics::text::LineHeight;
use style_traits::CSSPixel;
use style_traits::ToCss;
use webrender_api::units::LayoutPixel;
use webrender_api::ExternalScrollId;
@ -199,12 +208,165 @@ pub fn process_node_scroll_area_request(_requested_node: OpaqueNode) -> Rect<i32
/// Return the resolved value of property for a given (pseudo)element.
/// <https://drafts.csswg.org/cssom/#resolved-value>
pub fn process_resolved_style_request<'dom>(
_context: &LayoutContext,
_node: impl LayoutNode<'dom>,
_pseudo: &Option<PseudoElement>,
_property: &PropertyId,
context: &LayoutContext,
node: impl LayoutNode<'dom>,
pseudo: &Option<PseudoElement>,
property: &PropertyId,
fragment_tree_root: Option<Arc<FragmentTreeRoot>>,
) -> String {
"".to_owned()
if !node.as_element().unwrap().has_data() {
return process_resolved_style_request_for_unstyled_node(context, node, pseudo, property);
}
// We call process_resolved_style_request after performing a whole-document
// traversal, so in the common case, the element is styled.
let layout_element = node.to_threadsafe().as_element().unwrap();
let layout_element = match *pseudo {
None => Some(layout_element),
Some(PseudoElement::Before) => layout_element.get_before_pseudo(),
Some(PseudoElement::After) => layout_element.get_after_pseudo(),
Some(_) => {
warn!("Got unexpected pseudo element type!");
None
},
};
let layout_element = match layout_element {
None => {
// The pseudo doesn't exist, return nothing. Chrome seems to query
// the element itself in this case, Firefox uses the resolved value.
// https://www.w3.org/Bugs/Public/show_bug.cgi?id=29006
return String::new();
},
Some(layout_element) => layout_element,
};
let style = &*layout_element.resolved_style();
let longhand_id = match *property {
PropertyId::LonghandAlias(id, _) | PropertyId::Longhand(id) => id,
// Firefox returns blank strings for the computed value of shorthands,
// so this should be web-compatible.
PropertyId::ShorthandAlias(..) | PropertyId::Shorthand(_) => return String::new(),
PropertyId::Custom(ref name) => {
return style.computed_value_to_string(PropertyDeclarationId::Custom(name));
},
}
.to_physical(style.writing_mode);
let computed_style =
|| style.computed_value_to_string(PropertyDeclarationId::Longhand(longhand_id));
// We do not yet support pseudo content.
if pseudo.is_some() {
return computed_style();
}
// https://drafts.csswg.org/cssom/#dom-window-getcomputedstyle
// Here we are trying to conform to the specification that says that getComputedStyle
// should return the used values in certain circumstances. For size and positional
// properties we might need to walk the Fragment tree to figure those out. We always
// fall back to returning the computed value.
// For line height, the resolved value is the computed value if it
// is "normal" and the used value otherwise.
if longhand_id == LonghandId::LineHeight {
let font_size = style.get_font().font_size.size.0;
return match style.get_inherited_text().line_height {
LineHeight::Normal => computed_style(),
LineHeight::Number(value) => (font_size * value.0).to_css_string(),
LineHeight::Length(value) => value.0.to_css_string(),
};
}
// https://drafts.csswg.org/cssom/#dom-window-getcomputedstyle
// The properties that we calculate below all resolve to the computed value
// when the element is display:none or display:contents.
let display = style.get_box().display;
if display.is_none() || display.is_contents() {
return computed_style();
}
let fragment_tree_root = match fragment_tree_root {
Some(fragment_tree_root) => fragment_tree_root,
None => return computed_style(),
};
fragment_tree_root
.find(|fragment, containing_block| {
let box_fragment = match fragment {
Fragment::Box(ref box_fragment) if box_fragment.tag == node.opaque() => {
box_fragment
},
_ => return None,
};
let positioned = style.get_box().position != Position::Static;
let content_rect = box_fragment
.content_rect
.to_physical(box_fragment.style.writing_mode, &containing_block);
let margins = box_fragment
.margin
.to_physical(box_fragment.style.writing_mode);
let padding = box_fragment
.padding
.to_physical(box_fragment.style.writing_mode);
match longhand_id {
LonghandId::Width => Some(content_rect.size.width),
LonghandId::Height => Some(content_rect.size.height),
LonghandId::MarginBottom => Some(margins.bottom),
LonghandId::MarginTop => Some(margins.top),
LonghandId::MarginLeft => Some(margins.left),
LonghandId::MarginRight => Some(margins.right),
LonghandId::PaddingBottom => Some(padding.bottom),
LonghandId::PaddingTop => Some(padding.top),
LonghandId::PaddingLeft => Some(padding.left),
LonghandId::PaddingRight => Some(padding.right),
// TODO(mrobinson): These following values are often wrong, because these are not
// exactly the "used value" for the positional properties. The real used values are
// lost by the time the Fragment tree is constructed, so we may need to record them in
// the tree to properly answer this query. That said, we can return an okayish value
// sometimes simply by using the calculated position in the containing block.
LonghandId::Top if positioned => Some(content_rect.origin.y),
LonghandId::Left if positioned => Some(content_rect.origin.x),
_ => None,
}
.map(|value| value.to_css_string())
})
.unwrap_or_else(computed_style)
}
pub fn process_resolved_style_request_for_unstyled_node<'dom>(
context: &LayoutContext,
node: impl LayoutNode<'dom>,
pseudo: &Option<PseudoElement>,
property: &PropertyId,
) -> String {
// In a display: none subtree. No pseudo-element exists.
if pseudo.is_some() {
return String::new();
}
let mut tlc = ThreadLocalStyleContext::new(&context.style_context);
let mut context = StyleContext {
shared: &context.style_context,
thread_local: &mut tlc,
};
let element = node.as_element().unwrap();
let styles = resolve_style(&mut context, element, RuleInclusion::All, pseudo.as_ref());
let style = styles.primary();
let longhand_id = match *property {
PropertyId::LonghandAlias(id, _) | PropertyId::Longhand(id) => id,
// Firefox returns blank strings for the computed value of shorthands,
// so this should be web-compatible.
PropertyId::ShorthandAlias(..) | PropertyId::Shorthand(_) => return String::new(),
PropertyId::Custom(ref name) => {
return style.computed_value_to_string(PropertyDeclarationId::Custom(name));
},
};
// No need to care about used values here, since we're on a display: none
// subtree, use the resolved value.
style.computed_value_to_string(PropertyDeclarationId::Longhand(longhand_id))
}
pub fn process_offset_parent_query(_requested_node: OpaqueNode) -> OffsetParentResponse {