servo/src/components/main/layout/layout_task.rs
2014-02-24 15:16:42 -05:00

864 lines
36 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 http://mozilla.org/MPL/2.0/. */
//! The layout task. Performs layout on the DOM, builds display lists and sends them to be
/// rendered.
use css::matching::{ApplicableDeclarations, ApplicableDeclarationsCache, MatchMethods};
use css::matching::{StyleSharingCandidateCache};
use css::select::new_stylist;
use css::node_style::StyledNode;
use layout::construct::{FlowConstructionResult, FlowConstructor, NoConstructionResult};
use layout::context::LayoutContext;
use layout::display_list_builder::{DisplayListBuilder, ToGfxColor};
use layout::flow::{Flow, FlowLeafSet, ImmutableFlowUtils, MutableFlowUtils, MutableOwnedFlowUtils};
use layout::flow::{PreorderFlowTraversal, PostorderFlowTraversal};
use layout::flow;
use layout::incremental::RestyleDamage;
use layout::parallel::{AssignHeightsAndStoreOverflowTraversalKind, BubbleWidthsTraversalKind};
use layout::parallel::{PaddedUnsafeFlow};
use layout::parallel;
use layout::util::{LayoutDataAccess, OpaqueNode, LayoutDataWrapper};
use layout::wrapper::{DomLeafSet, LayoutNode, TLayoutNode, ThreadSafeLayoutNode};
use extra::url::Url;
use extra::arc::{Arc, MutexArc};
use geom::rect::Rect;
use geom::size::Size2D;
use gfx::display_list::{ClipDisplayItemClass, DisplayItem, DisplayItemIterator};
use gfx::display_list::{DisplayList, DisplayListCollection};
use gfx::font_context::FontContextInfo;
use gfx::opts::Opts;
use gfx::render_task::{RenderMsg, RenderChan, RenderLayer};
use gfx::{render_task, color};
use script::dom::bindings::js::JS;
use script::dom::event::ReflowEvent;
use script::dom::node::{ElementNodeTypeId, LayoutDataRef, Node};
use script::dom::element::{HTMLBodyElementTypeId, HTMLHtmlElementTypeId};
use script::layout_interface::{AddStylesheetMsg, ContentBoxQuery};
use script::layout_interface::{ContentBoxesQuery, ContentBoxesResponse, ExitNowMsg, LayoutQuery};
use script::layout_interface::{HitTestQuery, ContentBoxResponse, HitTestResponse, MouseOverQuery, MouseOverResponse};
use script::layout_interface::{ContentChangedDocumentDamage, LayoutChan, Msg, PrepareToExitMsg};
use script::layout_interface::{QueryMsg, ReapLayoutDataMsg, Reflow, ReflowDocumentDamage, UntrustedNodeAddress};
use script::layout_interface::{ReflowForDisplay, ReflowMsg};
use script::script_task::{ReflowCompleteMsg, ScriptChan, SendEventMsg};
use servo_msg::constellation_msg::{ConstellationChan, PipelineId, Failure, FailureMsg};
use servo_net::image_cache_task::{ImageCacheTask, ImageResponseMsg};
use servo_net::local_image_cache::{ImageResponder, LocalImageCache};
use servo_util::geometry::Au;
use servo_util::time::{ProfilerChan, profile};
use servo_util::time;
use servo_util::task::send_on_failure;
use servo_util::workqueue::WorkQueue;
use std::cast::transmute;
use std::cast;
use std::cell::RefCell;
use std::comm::Port;
use std::ptr;
use std::task;
use std::util;
use style::{AuthorOrigin, ComputedValues, Stylesheet, Stylist};
use style;
/// Information needed by the layout task.
pub struct LayoutTask {
/// The ID of the pipeline that we belong to.
id: PipelineId,
/// The port on which we receive messages.
port: Port<Msg>,
//// The channel to send messages to ourself.
chan: LayoutChan,
/// The channel on which messages can be sent to the constellation.
constellation_chan: ConstellationChan,
/// The channel on which messages can be sent to the script task.
script_chan: ScriptChan,
/// The channel on which messages can be sent to the painting task.
render_chan: RenderChan<OpaqueNode>,
/// The channel on which messages can be sent to the image cache.
image_cache_task: ImageCacheTask,
/// The local image cache.
local_image_cache: MutexArc<LocalImageCache>,
/// The set of leaves in the DOM tree.
dom_leaf_set: Arc<DomLeafSet>,
/// The set of leaves in the flow tree.
flow_leaf_set: Arc<FlowLeafSet>,
/// The size of the viewport.
screen_size: Size2D<Au>,
/// A cached display list.
display_list_collection: Option<Arc<DisplayListCollection<OpaqueNode>>>,
stylist: ~Stylist,
/// The initial set of CSS values.
initial_css_values: Arc<ComputedValues>,
/// The workers that we use for parallel operation.
parallel_traversal: Option<WorkQueue<*mut LayoutContext,PaddedUnsafeFlow>>,
/// The channel on which messages can be sent to the profiler.
profiler_chan: ProfilerChan,
opts: Opts
}
/// The damage computation traversal.
#[deriving(Clone)]
struct ComputeDamageTraversal;
impl PostorderFlowTraversal for ComputeDamageTraversal {
#[inline]
fn process(&mut self, flow: &mut Flow) -> bool {
let mut damage = flow::base(flow).restyle_damage;
for child in flow::child_iter(flow) {
damage.union_in_place(flow::base(child).restyle_damage.propagate_up())
}
flow::mut_base(flow).restyle_damage = damage;
true
}
}
/// Propagates restyle damage up and down the tree as appropriate.
///
/// FIXME(pcwalton): Merge this with flow tree building and/or other traversals.
struct PropagateDamageTraversal {
all_style_damage: bool,
}
impl PreorderFlowTraversal for PropagateDamageTraversal {
#[inline]
fn process(&mut self, flow: &mut Flow) -> bool {
if self.all_style_damage {
flow::mut_base(flow).restyle_damage.union_in_place(RestyleDamage::all())
}
debug!("restyle damage = {:?}", flow::base(flow).restyle_damage);
let prop = flow::base(flow).restyle_damage.propagate_down();
if prop.is_nonempty() {
for kid_ctx in flow::child_iter(flow) {
flow::mut_base(kid_ctx).restyle_damage.union_in_place(prop)
}
}
true
}
}
/// The flow tree verification traversal. This is only on in debug builds.
#[cfg(debug)]
struct FlowTreeVerificationTraversal;
#[cfg(debug)]
impl PreorderFlowTraversal for FlowTreeVerificationTraversal {
#[inline]
fn process(&mut self, flow: &mut Flow) -> bool {
let base = flow::base(flow);
if !base.flags_info.flags.is_leaf() && !base.flags_info.flags.is_nonleaf() {
println("flow tree verification failed: flow wasn't a leaf or a nonleaf!");
flow.dump();
fail!("flow tree verification failed")
}
true
}
}
/// The bubble-widths traversal, the first part of layout computation. This computes preferred
/// and intrinsic widths and bubbles them up the tree.
pub struct BubbleWidthsTraversal<'a> {
layout_context: &'a mut LayoutContext,
}
impl<'a> PostorderFlowTraversal for BubbleWidthsTraversal<'a> {
#[inline]
fn process(&mut self, flow: &mut Flow) -> bool {
flow.bubble_widths(self.layout_context);
true
}
// FIXME: We can't prune until we start reusing flows
/*
#[inline]
fn should_prune(&mut self, flow: &mut Flow) -> bool {
flow::mut_base(flow).restyle_damage.lacks(BubbleWidths)
}
*/
}
/// The assign-widths traversal. In Gecko this corresponds to `Reflow`.
struct AssignWidthsTraversal<'a>(&'a mut LayoutContext);
impl<'a> PreorderFlowTraversal for AssignWidthsTraversal<'a> {
#[inline]
fn process(&mut self, flow: &mut Flow) -> bool {
flow.assign_widths(**self);
true
}
}
/// The assign-heights-and-store-overflow traversal, the last (and most expensive) part of layout
/// computation. Determines the final heights for all layout objects, computes positions, and
/// computes overflow regions. In Gecko this corresponds to `FinishAndStoreOverflow`.
pub struct AssignHeightsAndStoreOverflowTraversal<'a> {
layout_context: &'a mut LayoutContext,
}
impl<'a> PostorderFlowTraversal for AssignHeightsAndStoreOverflowTraversal<'a> {
#[inline]
fn process(&mut self, flow: &mut Flow) -> bool {
flow.assign_height(self.layout_context);
flow.store_overflow(self.layout_context);
true
}
#[inline]
fn should_process(&mut self, flow: &mut Flow) -> bool {
!flow::base(flow).flags_info.flags.inorder()
}
}
struct LayoutImageResponder {
id: PipelineId,
script_chan: ScriptChan,
}
impl ImageResponder for LayoutImageResponder {
fn respond(&self) -> proc(ImageResponseMsg) {
let id = self.id.clone();
let script_chan = self.script_chan.clone();
let f: proc(ImageResponseMsg) = proc(_) {
drop(script_chan.try_send(SendEventMsg(id.clone(), ReflowEvent)))
};
f
}
}
impl LayoutTask {
/// Spawns a new layout task.
pub fn create(id: PipelineId,
port: Port<Msg>,
chan: LayoutChan,
constellation_chan: ConstellationChan,
failure_msg: Failure,
script_chan: ScriptChan,
render_chan: RenderChan<OpaqueNode>,
img_cache_task: ImageCacheTask,
opts: Opts,
profiler_chan: ProfilerChan,
shutdown_chan: Chan<()>) {
let mut builder = task::task();
send_on_failure(&mut builder, FailureMsg(failure_msg), (*constellation_chan).clone());
builder.name("LayoutTask");
builder.spawn(proc() {
{ // Ensures layout task is destroyed before we send shutdown message
let mut layout = LayoutTask::new(id,
port,
chan,
constellation_chan,
script_chan,
render_chan,
img_cache_task,
&opts,
profiler_chan);
layout.start();
}
shutdown_chan.send(());
});
}
/// Creates a new `LayoutTask` structure.
fn new(id: PipelineId,
port: Port<Msg>,
chan: LayoutChan,
constellation_chan: ConstellationChan,
script_chan: ScriptChan,
render_chan: RenderChan<OpaqueNode>,
image_cache_task: ImageCacheTask,
opts: &Opts,
profiler_chan: ProfilerChan)
-> LayoutTask {
let local_image_cache = MutexArc::new(LocalImageCache(image_cache_task.clone()));
let screen_size = Size2D(Au(0), Au(0));
let parallel_traversal = if opts.layout_threads != 1 {
Some(WorkQueue::new(opts.layout_threads, ptr::mut_null()))
} else {
None
};
LayoutTask {
id: id,
port: port,
chan: chan,
constellation_chan: constellation_chan,
script_chan: script_chan,
render_chan: render_chan,
image_cache_task: image_cache_task.clone(),
local_image_cache: local_image_cache,
screen_size: screen_size,
dom_leaf_set: Arc::new(DomLeafSet::new()),
flow_leaf_set: Arc::new(FlowLeafSet::new()),
display_list_collection: None,
stylist: ~new_stylist(),
initial_css_values: Arc::new(style::initial_values()),
parallel_traversal: parallel_traversal,
profiler_chan: profiler_chan,
opts: opts.clone()
}
}
/// Starts listening on the port.
fn start(&mut self) {
while self.handle_request() {
// Loop indefinitely.
}
}
// Create a layout context for use in building display lists, hit testing, &c.
fn build_layout_context(&self, reflow_root: &LayoutNode) -> LayoutContext {
let font_context_info = FontContextInfo {
backend: self.opts.render_backend,
needs_font_list: true,
profiler_chan: self.profiler_chan.clone(),
};
LayoutContext {
image_cache: self.local_image_cache.clone(),
screen_size: self.screen_size.clone(),
constellation_chan: self.constellation_chan.clone(),
dom_leaf_set: self.dom_leaf_set.clone(),
flow_leaf_set: self.flow_leaf_set.clone(),
layout_chan: self.chan.clone(),
font_context_info: font_context_info,
stylist: &*self.stylist,
initial_css_values: self.initial_css_values.clone(),
reflow_root: OpaqueNode::from_layout_node(reflow_root),
}
}
/// Receives and dispatches messages from the port.
fn handle_request(&mut self) -> bool {
match self.port.recv() {
AddStylesheetMsg(sheet) => self.handle_add_stylesheet(sheet),
ReflowMsg(data) => {
profile(time::LayoutPerformCategory, self.profiler_chan.clone(), || {
self.handle_reflow(data);
});
}
QueryMsg(query) => {
let mut query = Some(query);
profile(time::LayoutQueryCategory, self.profiler_chan.clone(), || {
self.handle_query(query.take_unwrap());
});
}
ReapLayoutDataMsg(dead_layout_data) => {
unsafe {
self.handle_reap_layout_data(dead_layout_data)
}
}
PrepareToExitMsg(response_chan) => {
debug!("layout: PrepareToExitMsg received");
self.prepare_to_exit(response_chan);
return false
}
ExitNowMsg => {
debug!("layout: ExitNowMsg received");
self.exit_now();
return false
}
}
true
}
/// Enters a quiescent state in which no new messages except for `ReapLayoutDataMsg` will be
/// processed until an `ExitNowMsg` is received. A pong is immediately sent on the given
/// response channel.
fn prepare_to_exit(&mut self, response_chan: Chan<()>) {
response_chan.send(());
loop {
match self.port.recv() {
ReapLayoutDataMsg(dead_layout_data) => {
unsafe {
self.handle_reap_layout_data(dead_layout_data)
}
}
ExitNowMsg => {
debug!("layout task is exiting...");
self.exit_now();
break
}
_ => {
fail!("layout: message that wasn't `ExitNowMsg` received after \
`PrepareToExitMsg`")
}
}
}
}
/// Shuts down the layout task now. If there are any DOM nodes left, layout will now (safely)
/// crash.
fn exit_now(&mut self) {
let (response_port, response_chan) = Chan::new();
match self.parallel_traversal {
None => {}
Some(ref mut traversal) => traversal.shutdown(),
}
self.render_chan.send(render_task::ExitMsg(Some(response_chan)));
response_port.recv()
}
fn handle_add_stylesheet(&mut self, sheet: Stylesheet) {
self.stylist.add_stylesheet(sheet, AuthorOrigin)
}
/// Builds the flow tree.
///
/// This corresponds to the various `nsCSSFrameConstructor` methods in Gecko or
/// `createRendererIfNeeded` in WebKit. Note, however that in WebKit `createRendererIfNeeded`
/// is intertwined with selector matching, making it difficult to compare directly. It is
/// marked `#[inline(never)]` to aid benchmarking in sampling profilers.
#[inline(never)]
fn construct_flow_tree(&self, layout_context: &mut LayoutContext, node: &mut LayoutNode, url: &Url) -> ~Flow {
let mut node = ThreadSafeLayoutNode::new(node);
node.traverse_postorder_mut(&mut FlowConstructor::init(layout_context, url));
let mut layout_data_ref = node.mutate_layout_data();
let result = match *layout_data_ref.get() {
Some(ref mut layout_data) => {
util::replace(&mut layout_data.data.flow_construction_result, NoConstructionResult)
}
None => fail!("no layout data for root node"),
};
let mut flow = match result {
FlowConstructionResult(flow) => flow,
_ => fail!("Flow construction didn't result in a flow at the root of the tree!"),
};
flow.mark_as_root();
flow
}
/// Performs layout constraint solving.
///
/// This corresponds to `Reflow()` in Gecko and `layout()` in WebKit/Blink and should be
/// benchmarked against those two. It is marked `#[inline(never)]` to aid profiling.
#[inline(never)]
fn solve_constraints(&mut self,
layout_root: &mut Flow,
layout_context: &mut LayoutContext) {
{
let mut traversal = BubbleWidthsTraversal {
layout_context: layout_context,
};
layout_root.traverse_postorder(&mut traversal);
}
// FIXME(kmc): We want to prune nodes without the Reflow restyle damage
// bit, but FloatContext values can't be reused, so we need to
// recompute them every time.
// NOTE: this currently computes borders, so any pruning should separate that operation
// out.
layout_root.traverse_preorder(&mut AssignWidthsTraversal(layout_context));
// FIXME(pcwalton): Prune this pass as well.
{
let mut traversal = AssignHeightsAndStoreOverflowTraversal {
layout_context: layout_context,
};
layout_root.traverse_postorder(&mut traversal);
}
}
/// Performs layout constraint solving in parallel.
///
/// This corresponds to `Reflow()` in Gecko and `layout()` in WebKit/Blink and should be
/// benchmarked against those two. It is marked `#[inline(never)]` to aid profiling.
#[inline(never)]
fn solve_constraints_parallel(&mut self,
layout_root: &mut Flow,
layout_context: &mut LayoutContext) {
match self.parallel_traversal {
None => fail!("solve_contraints_parallel() called with no parallel traversal ready"),
Some(ref mut traversal) => {
parallel::traverse_flow_tree(BubbleWidthsTraversalKind,
&self.flow_leaf_set,
self.profiler_chan.clone(),
layout_context,
traversal);
// NOTE: this currently computes borders, so any pruning should separate that
// operation out.
// TODO(pcwalton): Run this in parallel as well. This will require a bit more work
// because this is a top-down traversal, unlike the others.
layout_root.traverse_preorder(&mut AssignWidthsTraversal(layout_context));
parallel::traverse_flow_tree(AssignHeightsAndStoreOverflowTraversalKind,
&self.flow_leaf_set,
self.profiler_chan.clone(),
layout_context,
traversal);
}
}
}
/// Verifies that every node was either marked as a leaf or as a nonleaf in the flow tree.
/// This is only on in debug builds.
#[inline(never)]
#[cfg(debug)]
fn verify_flow_tree(&mut self, layout_root: &mut ~Flow) {
let mut traversal = FlowTreeVerificationTraversal;
layout_root.traverse_preorder(&mut traversal);
}
#[cfg(not(debug))]
fn verify_flow_tree(&mut self, _: &mut ~Flow) {
}
/// The high-level routine that performs layout tasks.
fn handle_reflow(&mut self, data: &Reflow) {
// FIXME: Isolate this transmutation into a "bridge" module.
let node: &mut LayoutNode = unsafe {
let mut node: JS<Node> = JS::from_trusted_node_address(data.document_root);
transmute(&mut node)
};
debug!("layout: received layout request for: {:s}", data.url.to_str());
debug!("layout: damage is {:?}", data.damage);
debug!("layout: parsed Node tree");
debug!("{:?}", node.dump());
// Reset the image cache.
unsafe {
self.local_image_cache.unsafe_access(|local_image_cache| {
local_image_cache.next_round(self.make_on_image_available_cb())
});
}
// true => Do the reflow with full style damage, because content
// changed or the window was resized.
let mut all_style_damage = match data.damage.level {
ContentChangedDocumentDamage => true,
_ => false
};
let current_screen_size = Size2D(Au::from_px(data.window_size.width as int),
Au::from_px(data.window_size.height as int));
if self.screen_size != current_screen_size {
all_style_damage = true
}
self.screen_size = current_screen_size;
// Create a layout context for use throughout the following passes.
let mut layout_ctx = self.build_layout_context(node);
let mut layout_root = profile(time::LayoutStyleRecalcCategory,
self.profiler_chan.clone(),
|| {
// Perform CSS selector matching if necessary.
match data.damage.level {
ReflowDocumentDamage => {}
_ => {
profile(time::LayoutSelectorMatchCategory, self.profiler_chan.clone(), || {
match self.parallel_traversal {
None => {
let mut applicable_declarations = ApplicableDeclarations::new();
let mut applicable_declarations_cache =
ApplicableDeclarationsCache::new();
let mut style_sharing_candidate_cache =
StyleSharingCandidateCache::new();
node.match_and_cascade_subtree(self.stylist,
&layout_ctx.layout_chan,
&mut applicable_declarations,
layout_ctx.initial_css_values.get(),
&mut applicable_declarations_cache,
&mut style_sharing_candidate_cache,
None)
}
Some(ref mut traversal) => {
parallel::match_and_cascade_subtree(node,
&mut layout_ctx,
traversal)
}
}
})
}
}
// Construct the flow tree.
profile(time::LayoutTreeBuilderCategory,
self.profiler_chan.clone(),
|| self.construct_flow_tree(&mut layout_ctx, node, &data.url))
});
// Verification of the flow tree, which ensures that all nodes were either marked as leaves
// or as non-leaves. This becomes a no-op in release builds. (It is inconsequential to
// memory safety but is a useful debugging tool.)
self.verify_flow_tree(&mut layout_root);
// Propagate damage.
profile(time::LayoutDamagePropagateCategory, self.profiler_chan.clone(), || {
layout_root.traverse_preorder(&mut PropagateDamageTraversal {
all_style_damage: all_style_damage
});
layout_root.traverse_postorder(&mut ComputeDamageTraversal.clone());
});
// Perform the primary layout passes over the flow tree to compute the locations of all
// the boxes.
profile(time::LayoutMainCategory, self.profiler_chan.clone(), || {
match self.parallel_traversal {
None => {
// Sequential mode.
self.solve_constraints(layout_root, &mut layout_ctx)
}
Some(_) => {
// Parallel mode.
self.solve_constraints_parallel(layout_root, &mut layout_ctx)
}
}
});
// Build the display list if necessary, and send it to the renderer.
if data.goal == ReflowForDisplay {
profile(time::LayoutDispListBuildCategory, self.profiler_chan.clone(), || {
let root_size = flow::base(layout_root).position.size;
let mut display_list_collection = DisplayListCollection::new();
display_list_collection.add_list(DisplayList::<OpaqueNode>::new());
let display_list_collection = ~RefCell::new(display_list_collection);
let dirty = flow::base(layout_root).position.clone();
let display_list_builder = DisplayListBuilder {
ctx: &layout_ctx,
};
layout_root.build_display_lists(&display_list_builder, &root_size, &dirty, 0u, display_list_collection);
let display_list_collection = Arc::new(display_list_collection.unwrap());
let mut color = color::rgba(255.0, 255.0, 255.0, 255.0);
for child in node.traverse_preorder() {
if child.type_id() == ElementNodeTypeId(HTMLHtmlElementTypeId) ||
child.type_id() == ElementNodeTypeId(HTMLBodyElementTypeId) {
let element_bg_color = {
let thread_safe_child = ThreadSafeLayoutNode::new(&child);
thread_safe_child.style()
.get()
.resolve_color(thread_safe_child.style()
.get()
.Background
.get()
.background_color)
.to_gfx_color()
};
match element_bg_color {
color::rgba(0., 0., 0., 0.) => {}
_ => {
color = element_bg_color;
break;
}
}
}
}
let render_layer = RenderLayer {
display_list_collection: display_list_collection.clone(),
size: Size2D(root_size.width.to_nearest_px() as uint,
root_size.height.to_nearest_px() as uint),
color: color
};
self.display_list_collection = Some(display_list_collection.clone());
debug!("Layout done!");
self.render_chan.send(RenderMsg(render_layer));
});
}
layout_root.destroy(self.flow_leaf_set.get());
// Tell script that we're done.
//
// FIXME(pcwalton): This should probably be *one* channel, but we can't fix this without
// either select or a filtered recv() that only looks for messages of a given type.
data.script_join_chan.send(());
data.script_chan.send(ReflowCompleteMsg(self.id, data.id));
}
/// Handles a query from the script task. This is the main routine that DOM functions like
/// `getClientRects()` or `getBoundingClientRect()` ultimately invoke.
fn handle_query(&self, query: LayoutQuery) {
match query {
// The neat thing here is that in order to answer the following two queries we only
// need to compare nodes for equality. Thus we can safely work only with `OpaqueNode`.
ContentBoxQuery(node, reply_chan) => {
let node = OpaqueNode::from_script_node(node);
fn union_boxes_for_node<'a>(
accumulator: &mut Option<Rect<Au>>,
mut iter: DisplayItemIterator<'a,OpaqueNode>,
node: OpaqueNode) {
for item in iter {
union_boxes_for_node(accumulator, item.children(), node);
if item.base().extra == node {
match *accumulator {
None => *accumulator = Some(item.base().bounds),
Some(ref mut acc) => *acc = acc.union(&item.base().bounds),
}
}
}
}
let mut rect = None;
for display_list in self.display_list_collection.as_ref().unwrap().get().iter() {
union_boxes_for_node(&mut rect, display_list.iter(), node);
}
reply_chan.send(ContentBoxResponse(rect.unwrap_or(Au::zero_rect())))
}
ContentBoxesQuery(node, reply_chan) => {
let node = OpaqueNode::from_script_node(node);
fn add_boxes_for_node<'a>(
accumulator: &mut ~[Rect<Au>],
mut iter: DisplayItemIterator<'a,OpaqueNode>,
node: OpaqueNode) {
for item in iter {
add_boxes_for_node(accumulator, item.children(), node);
if item.base().extra == node {
accumulator.push(item.base().bounds)
}
}
}
let mut boxes = ~[];
for display_list in self.display_list_collection.as_ref().unwrap().get().iter() {
add_boxes_for_node(&mut boxes, display_list.iter(), node);
}
reply_chan.send(ContentBoxesResponse(boxes))
}
HitTestQuery(_, point, reply_chan) => {
fn hit_test(x: Au, y: Au, list: &[DisplayItem<OpaqueNode>])
-> Option<HitTestResponse> {
for item in list.rev_iter() {
match *item {
ClipDisplayItemClass(ref cc) => {
let ret = hit_test(x, y, cc.child_list);
if !ret.is_none() {
return ret;
}
}
_ => {}
}
}
for item in list.rev_iter() {
match *item {
ClipDisplayItemClass(_) => continue,
_ => {}
}
let bounds = item.bounds();
// TODO(tikue): This check should really be performed by a method of
// DisplayItem.
if x < bounds.origin.x + bounds.size.width &&
bounds.origin.x <= x &&
y < bounds.origin.y + bounds.size.height &&
bounds.origin.y <= y {
return Some(HitTestResponse(item.base()
.extra
.to_untrusted_node_address()))
}
}
let ret: Option<HitTestResponse> = None;
ret
}
for display_list in self.display_list_collection.as_ref().unwrap().get().lists.rev_iter() {
let (x, y) = (Au::from_frac_px(point.x as f64),
Au::from_frac_px(point.y as f64));
let resp = hit_test(x,y,display_list.list);
if resp.is_some() {
reply_chan.send(Ok(resp.unwrap()));
return
}
}
reply_chan.send(Err(()));
}
MouseOverQuery(_, point, reply_chan) => {
fn mouse_over_test(x: Au, y: Au, list: &[DisplayItem<OpaqueNode>], result: &mut ~[UntrustedNodeAddress]) {
for item in list.rev_iter() {
match *item {
ClipDisplayItemClass(ref cc) => {
mouse_over_test(x, y, cc.child_list, result);
}
_ => {}
}
}
for item in list.rev_iter() {
let bounds = item.bounds();
// TODO(tikue): This check should really be performed by a method of
// DisplayItem.
if x < bounds.origin.x + bounds.size.width &&
bounds.origin.x <= x &&
y < bounds.origin.y + bounds.size.height &&
bounds.origin.y <= y {
result.push(item.base()
.extra
.to_untrusted_node_address());
}
}
}
let mut mouse_over_list:~[UntrustedNodeAddress] = ~[];
for display_list in self.display_list_collection.as_ref().unwrap().get().lists.rev_iter() {
let (x, y) = (Au::from_frac_px(point.x as f64),
Au::from_frac_px(point.y as f64));
mouse_over_test(x,y,display_list.list, &mut mouse_over_list);
}
if mouse_over_list.is_empty() {
reply_chan.send(Err(()));
} else {
reply_chan.send(Ok(MouseOverResponse(mouse_over_list)));
}
}
}
}
// When images can't be loaded in time to display they trigger
// this callback in some task somewhere. This will send a message
// to the script task, and ultimately cause the image to be
// re-requested. We probably don't need to go all the way back to
// the script task for this.
fn make_on_image_available_cb(&self) -> ~ImageResponder:Send {
// This has a crazy signature because the image cache needs to
// make multiple copies of the callback, and the dom event
// channel is not a copyable type, so this is actually a
// little factory to produce callbacks
~LayoutImageResponder {
id: self.id.clone(),
script_chan: self.script_chan.clone(),
} as ~ImageResponder:Send
}
/// Handles a message to destroy layout data. Layout data must be destroyed on *this* task
/// because it contains local managed pointers.
unsafe fn handle_reap_layout_data(&self, layout_data: LayoutDataRef) {
let mut layout_data_ref = layout_data.borrow_mut();
let _: Option<LayoutDataWrapper> = cast::transmute(
util::replace(layout_data_ref.get(), None));
}
}