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Implement getComputedStyle

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This commit is contained in:
David Zbarsky 2015-07-27 23:05:18 -04:00
parent 416931f4be
commit e484d6b5e3
24 changed files with 886 additions and 152 deletions
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262
components/layout/layout_task.rs
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@ -10,6 +10,7 @@
use animation;
use construct::ConstructionResult;
use context::{SharedLayoutContext, heap_size_of_local_context};
use cssparser::ToCss;
use data::LayoutDataWrapper;
use display_list_builder::ToGfxColor;
use flow::{self, Flow, ImmutableFlowUtils, MutableFlowUtils, MutableOwnedFlowUtils};
@ -55,9 +56,10 @@ use script::dom::node::{LayoutData, Node};
use script::layout_interface::{Animation, ContentBoxResponse, ContentBoxesResponse, NodeGeometryResponse};
use script::layout_interface::{HitTestResponse, LayoutChan, LayoutRPC, MouseOverResponse};
use script::layout_interface::{NewLayoutTaskInfo, Msg, Reflow, ReflowGoal, ReflowQueryType};
use script::layout_interface::{ScriptLayoutChan, ScriptReflow, TrustedNodeAddress};
use script::layout_interface::{ResolvedStyleResponse, ScriptLayoutChan, ScriptReflow, TrustedNodeAddress};
use script_traits::{ConstellationControlMsg, LayoutControlMsg, OpaqueScriptLayoutChannel};
use script_traits::{ScriptControlChan, StylesheetLoadResponder};
use selectors::parser::PseudoElement;
use serde::json;
use std::borrow::ToOwned;
use std::cell::Cell;
@ -67,20 +69,23 @@ use std::mem::transmute;
use std::ops::{Deref, DerefMut};
use std::sync::mpsc::{channel, Sender, Receiver, Select};
use std::sync::{Arc, Mutex, MutexGuard};
use string_cache::Atom;
use style::computed_values::{filter, mix_blend_mode};
use style::media_queries::{MediaType, MediaQueryList, Device};
use style::properties::style_structs;
use style::properties::longhands::{display, position};
use style::selector_matching::Stylist;
use style::stylesheets::{Origin, Stylesheet, CSSRuleIteratorExt};
use url::Url;
use util::cursor::Cursor;
use util::geometry::{Au, MAX_RECT};
use util::logical_geometry::LogicalPoint;
use util::geometry::{Au, MAX_RECT, ZERO_POINT};
use util::logical_geometry::{LogicalPoint, WritingMode};
use util::mem::HeapSizeOf;
use util::opts;
use util::task::spawn_named_with_send_on_failure;
use util::task_state;
use util::workqueue::WorkQueue;
use wrapper::ThreadSafeLayoutNode;
/// The number of screens of data we're allowed to generate display lists for in each direction.
pub const DISPLAY_PORT_SIZE_FACTOR: i32 = 8;
@ -129,6 +134,9 @@ pub struct LayoutTaskData {
/// A queued response for the client {top, left, width, height} of a node in pixels.
pub client_rect_response: Rect<i32>,
/// A queued response for the resolved style property of an element.
pub resolved_style_response: Option<String>,
/// The list of currently-running animations.
pub running_animations: Vec<Animation>,
@ -372,6 +380,7 @@ impl LayoutTask {
content_box_response: Rect::zero(),
content_boxes_response: Vec::new(),
client_rect_response: Rect::zero(),
resolved_style_response: None,
running_animations: Vec::new(),
visible_rects: Arc::new(HashMap::with_hash_state(Default::default())),
new_animations_receiver: new_animations_receiver,
@ -864,6 +873,127 @@ impl LayoutTask {
rw_data.client_rect_response = iterator.client_rect;
}
// Compute the resolved value of property for a given (pseudo)element.
// Stores the result in rw_data.resolved_style_response.
// https://drafts.csswg.org/cssom/#resolved-value
fn process_resolved_style_request<'a>(&'a self,
requested_node: TrustedNodeAddress,
pseudo: &Option<PseudoElement>,
property: &Atom,
layout_root: &mut FlowRef,
rw_data: &mut RWGuard<'a>) {
// FIXME: Isolate this transmutation into a "bridge" module.
// FIXME(rust#16366): The following line had to be moved because of a
// rustc bug. It should be in the next unsafe block.
let node: LayoutJS<Node> = unsafe {
LayoutJS::from_trusted_node_address(requested_node)
};
let node: &LayoutNode = unsafe {
transmute(&node)
};
let layout_node = ThreadSafeLayoutNode::new(node);
let layout_node = match pseudo {
&Some(PseudoElement::Before) => layout_node.get_before_pseudo(),
&Some(PseudoElement::After) => layout_node.get_after_pseudo(),
_ => Some(layout_node)
};
let layout_node = match layout_node {
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
rw_data.resolved_style_response = None;
return;
}
Some(layout_node) => layout_node
};
let style = &*layout_node.style();
let positioned = match style.get_box().position {
position::computed_value::T::relative |
/*position::computed_value::T::sticky |*/
position::computed_value::T::fixed |
position::computed_value::T::absolute => true,
_ => false
};
//TODO: determine whether requested property applies to the element.
// eg. width does not apply to non-replaced inline elements.
// Existing browsers disagree about when left/top/right/bottom apply
// (Chrome seems to think they never apply and always returns resolved values).
// There are probably other quirks.
let applies = true;
// TODO: we will return neither the computed nor used value for margin and padding.
// Firefox returns blank strings for the computed value of shorthands,
// so this should be web-compatible.
match property.clone() {
atom!("margin-bottom") | atom!("margin-top") |
atom!("margin-left") | atom!("margin-right") |
atom!("padding-bottom") | atom!("padding-top") |
atom!("padding-left") | atom!("padding-right")
if applies && style.get_box().display != display::computed_value::T::none => {
let (margin_padding, side) = match *property {
atom!("margin-bottom") => (MarginPadding::Margin, Side::Bottom),
atom!("margin-top") => (MarginPadding::Margin, Side::Top),
atom!("margin-left") => (MarginPadding::Margin, Side::Left),
atom!("margin-right") => (MarginPadding::Margin, Side::Right),
atom!("padding-bottom") => (MarginPadding::Padding, Side::Bottom),
atom!("padding-top") => (MarginPadding::Padding, Side::Top),
atom!("padding-left") => (MarginPadding::Padding, Side::Left),
atom!("padding-right") => (MarginPadding::Padding, Side::Right),
_ => unreachable!()
};
let requested_node: OpaqueNode = OpaqueNodeMethods::from_script_node(requested_node);
let mut iterator =
MarginRetrievingFragmentBorderBoxIterator::new(requested_node,
side,
margin_padding,
style.writing_mode);
sequential::iterate_through_flow_tree_fragment_border_boxes(layout_root, &mut iterator);
rw_data.resolved_style_response = iterator.result.map(|r| r.to_css_string());
},
atom!("bottom") | atom!("top") | atom!("right") |
atom!("left") | atom!("width") | atom!("height")
if applies && positioned && style.get_box().display != display::computed_value::T::none => {
let layout_data = layout_node.borrow_layout_data();
let position = layout_data.as_ref().map(|layout_data| {
match layout_data.data.flow_construction_result {
ConstructionResult::Flow(ref flow_ref, _) =>
flow::base(flow_ref.deref()).stacking_relative_position,
// TODO search parents until we find node with a flow ref.
_ => ZERO_POINT
}
}).unwrap_or(ZERO_POINT);
let property = match *property {
atom!("bottom") => PositionProperty::Bottom,
atom!("top") => PositionProperty::Top,
atom!("left") => PositionProperty::Left,
atom!("right") => PositionProperty::Right,
atom!("width") => PositionProperty::Width,
atom!("height") => PositionProperty::Height,
_ => unreachable!()
};
let requested_node: OpaqueNode = OpaqueNodeMethods::from_script_node(requested_node);
let mut iterator =
PositionRetrievingFragmentBorderBoxIterator::new(requested_node,
property,
position);
sequential::iterate_through_flow_tree_fragment_border_boxes(layout_root, &mut iterator);
rw_data.resolved_style_response = iterator.result.map(|r| r.to_css_string());
},
// FIXME: implement used value computation for line-height
property => {
rw_data.resolved_style_response = style.computed_value_to_string(property.as_slice());
}
};
}
fn compute_abs_pos_and_build_display_list<'a>(&'a self,
data: &Reflow,
layout_root: &mut FlowRef,
@ -1052,15 +1182,14 @@ impl LayoutTask {
let mut root_flow = (*rw_data.root_flow.as_ref().unwrap()).clone();
match data.query_type {
ReflowQueryType::ContentBoxQuery(node) => {
self.process_content_box_request(node, &mut root_flow, &mut rw_data)
}
ReflowQueryType::ContentBoxesQuery(node) => {
self.process_content_boxes_request(node, &mut root_flow, &mut rw_data)
}
ReflowQueryType::NodeGeometryQuery(node) => {
self.process_node_geometry_request(node, &mut root_flow, &mut rw_data)
}
ReflowQueryType::ContentBoxQuery(node) =>
self.process_content_box_request(node, &mut root_flow, &mut rw_data),
ReflowQueryType::ContentBoxesQuery(node) =>
self.process_content_boxes_request(node, &mut root_flow, &mut rw_data),
ReflowQueryType::NodeGeometryQuery(node) =>
self.process_node_geometry_request(node, &mut root_flow, &mut rw_data),
ReflowQueryType::ResolvedStyleQuery(node, ref pseudo, ref property) =>
self.process_resolved_style_request(node, pseudo, property, &mut root_flow, &mut rw_data),
ReflowQueryType::NoQuery => {}
}
@ -1308,6 +1437,13 @@ impl LayoutRPC for LayoutRPCImpl {
}
}
/// Retrieves the resolved value for a CSS style property.
fn resolved_style(&self) -> ResolvedStyleResponse {
let &LayoutRPCImpl(ref rw_data) = self;
let rw_data = rw_data.lock().unwrap();
ResolvedStyleResponse(rw_data.resolved_style_response.clone())
}
/// Requests the node containing the point of interest.
fn hit_test(&self, _: TrustedNodeAddress, point: Point2D<f32>) -> Result<HitTestResponse, ()> {
let point = Point2D::new(Au::from_f32_px(point.x), Au::from_f32_px(point.y));
@ -1459,6 +1595,108 @@ impl FragmentBorderBoxIterator for FragmentLocatingFragmentIterator {
}
}
enum Side {
Left,
Right,
Bottom,
Top
}
enum MarginPadding {
Margin,
Padding
}
enum PositionProperty {
Left,
Right,
Top,
Bottom,
Width,
Height,
}
struct PositionRetrievingFragmentBorderBoxIterator {
node_address: OpaqueNode,
result: Option<Au>,
position: Point2D<Au>,
property: PositionProperty,
}
impl PositionRetrievingFragmentBorderBoxIterator {
fn new(node_address: OpaqueNode,
property: PositionProperty,
position: Point2D<Au>) -> PositionRetrievingFragmentBorderBoxIterator {
PositionRetrievingFragmentBorderBoxIterator {
node_address: node_address,
position: position,
property: property,
result: None,
}
}
}
impl FragmentBorderBoxIterator for PositionRetrievingFragmentBorderBoxIterator {
fn process(&mut self, _: &Fragment, border_box: &Rect<Au>) {
self.result =
Some(match self.property {
PositionProperty::Left => self.position.x,
PositionProperty::Top => self.position.y,
PositionProperty::Width => border_box.size.width,
PositionProperty::Height => border_box.size.height,
// TODO: the following 2 calculations are completely wrong.
// They should return the difference between the parent's and this
// fragment's border boxes.
PositionProperty::Right => border_box.max_x() + self.position.x,
PositionProperty::Bottom => border_box.max_y() + self.position.y,
});
}
fn should_process(&mut self, fragment: &Fragment) -> bool {
fragment.contains_node(self.node_address)
}
}
struct MarginRetrievingFragmentBorderBoxIterator {
node_address: OpaqueNode,
result: Option<Au>,
writing_mode: WritingMode,
margin_padding: MarginPadding,
side: Side,
}
impl MarginRetrievingFragmentBorderBoxIterator {
fn new(node_address: OpaqueNode, side: Side, margin_padding:
MarginPadding, writing_mode: WritingMode) -> MarginRetrievingFragmentBorderBoxIterator {
MarginRetrievingFragmentBorderBoxIterator {
node_address: node_address,
side: side,
margin_padding: margin_padding,
result: None,
writing_mode: writing_mode,
}
}
}
impl FragmentBorderBoxIterator for MarginRetrievingFragmentBorderBoxIterator {
fn process(&mut self, fragment: &Fragment, _: &Rect<Au>) {
let rect = match self.margin_padding {
MarginPadding::Margin => &fragment.margin,
MarginPadding::Padding => &fragment.border_padding
};
self.result = Some(match self.side {
Side::Left => rect.left(self.writing_mode),
Side::Right => rect.right(self.writing_mode),
Side::Bottom => rect.bottom(self.writing_mode),
Side::Top => rect.top(self.writing_mode)
});
}
fn should_process(&mut self, fragment: &Fragment) -> bool {
fragment.contains_node(self.node_address)
}
}
// The default computed value for background-color is transparent (see
// http://dev.w3.org/csswg/css-backgrounds/#background-color). However, we
// need to propagate the background color from the root HTML/Body