/* 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 //! painted. #![allow(unsafe_code)] use animation; use construct::ConstructionResult; use context::{SharedLayoutContext, SharedLayoutContextWrapper}; use css::node_style::StyledNode; use display_list_builder::ToGfxColor; use flow::{self, Flow, ImmutableFlowUtils, MutableFlowUtils, MutableOwnedFlowUtils}; use flow_ref::FlowRef; use fragment::{Fragment, FragmentBorderBoxIterator}; use incremental::{LayoutDamageComputation, REFLOW, REFLOW_ENTIRE_DOCUMENT, REPAINT}; use data::{LayoutDataAccess, LayoutDataWrapper}; use layout_debug; use opaque_node::OpaqueNodeMethods; use parallel::{self, UnsafeFlow}; use sequential; use wrapper::{LayoutNode, TLayoutNode}; use azure::azure::AzColor; use encoding::EncodingRef; use encoding::all::UTF_8; use geom::matrix2d::Matrix2D; use geom::point::Point2D; use geom::rect::Rect; use geom::scale_factor::ScaleFactor; use geom::size::Size2D; use gfx::color; use gfx::display_list::{ClippingRegion, DisplayItemMetadata, DisplayList, OpaqueNode}; use gfx::display_list::{StackingContext}; use gfx::font_cache_task::FontCacheTask; use gfx::paint_task::Msg as PaintMsg; use gfx::paint_task::{PaintChan, PaintLayer}; use layout_traits::{LayoutControlMsg, LayoutTaskFactory}; use log; use msg::compositor_msg::ScrollPolicy; use msg::constellation_msg::Msg as ConstellationMsg; use msg::constellation_msg::{ConstellationChan, Failure, PipelineExitType, PipelineId}; use profile::mem::{self, Report, ReportsChan}; use profile::time::{self, ProfilerMetadata, profile}; use profile::time::{TimerMetadataFrameType, TimerMetadataReflowType}; use net_traits::{load_bytes_iter, ResourceTask}; use net_traits::image_cache_task::{ImageCacheTask, ImageResponseMsg}; use net_traits::local_image_cache::{ImageResponder, LocalImageCache}; use script::dom::bindings::js::LayoutJS; use script::dom::node::{LayoutData, Node}; use script::layout_interface::{Animation, ContentBoxResponse, ContentBoxesResponse}; use script::layout_interface::{HitTestResponse, LayoutChan, LayoutRPC}; use script::layout_interface::{MouseOverResponse, Msg, Reflow, ReflowGoal, ReflowQueryType}; use script::layout_interface::{ScriptLayoutChan, ScriptReflow, TrustedNodeAddress}; use script_traits::{ConstellationControlMsg, CompositorEvent, OpaqueScriptLayoutChannel}; use script_traits::{ScriptControlChan, UntrustedNodeAddress}; use std::borrow::ToOwned; use std::cell::Cell; use std::mem::transmute; use std::ops::{Deref, DerefMut}; use std::ptr; use std::sync::mpsc::{channel, Sender, Receiver, Select}; use std::sync::{Arc, Mutex, MutexGuard}; use style::computed_values::{filter, mix_blend_mode}; use style::media_queries::{MediaType, MediaQueryList, Device}; use style::node::TNode; 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::mem::HeapSizeOf; use util::opts; use util::smallvec::{SmallVec, SmallVec1, VecLike}; use util::task::spawn_named_with_send_on_failure; use util::task_state; use util::workqueue::WorkQueue; /// Mutable data belonging to the LayoutTask. /// /// This needs to be protected by a mutex so we can do fast RPCs. pub struct LayoutTaskData { /// The root of the flow tree. pub root_flow: Option, /// The local image cache. pub local_image_cache: Arc>>, /// The channel on which messages can be sent to the constellation. pub constellation_chan: ConstellationChan, /// The size of the viewport. pub screen_size: Size2D, /// The root stacking context. pub stacking_context: Option>, /// Performs CSS selector matching and style resolution. pub stylist: Box, /// The workers that we use for parallel operation. pub parallel_traversal: Option>, /// The dirty rect. Used during display list construction. pub dirty: Rect, /// Starts at zero, and increased by one every time a layout completes. /// This can be used to easily check for invalid stale data. pub generation: u32, /// A queued response for the union of the content boxes of a node. pub content_box_response: Rect, /// A queued response for the content boxes of a node. pub content_boxes_response: Vec>, /// The list of currently-running animations. pub running_animations: Vec, /// Receives newly-discovered animations. pub new_animations_receiver: Receiver, /// A channel on which new animations that have been triggered by style recalculation can be /// sent. pub new_animations_sender: Sender, } /// Information needed by the layout task. pub struct LayoutTask { /// The ID of the pipeline that we belong to. pub id: PipelineId, /// The URL of the pipeline that we belong to. pub url: Url, /// Is the current reflow of an iframe, as opposed to a root window? pub is_iframe: bool, /// The port on which we receive messages from the script task. pub port: Receiver, /// The port on which we receive messages from the constellation pub pipeline_port: Receiver, /// The channel on which we or others can send messages to ourselves. pub chan: LayoutChan, /// The channel on which messages can be sent to the constellation. pub constellation_chan: ConstellationChan, /// The channel on which messages can be sent to the script task. pub script_chan: ScriptControlChan, /// The channel on which messages can be sent to the painting task. pub paint_chan: PaintChan, /// The channel on which messages can be sent to the time profiler. pub time_profiler_chan: time::ProfilerChan, /// The channel on which messages can be sent to the memory profiler. pub mem_profiler_chan: mem::ProfilerChan, /// The name used for the task's memory reporter. pub reporter_name: String, /// The channel on which messages can be sent to the resource task. pub resource_task: ResourceTask, /// The channel on which messages can be sent to the image cache. pub image_cache_task: ImageCacheTask, /// Public interface to the font cache task. pub font_cache_task: FontCacheTask, /// Is this the first reflow in this LayoutTask? pub first_reflow: Cell, /// A mutex to allow for fast, read-only RPC of layout's internal data /// structures, while still letting the LayoutTask modify them. /// /// All the other elements of this struct are read-only. pub rw_data: Arc>, } struct LayoutImageResponder { id: PipelineId, script_chan: ScriptControlChan, } impl ImageResponder for LayoutImageResponder { fn respond(&self) -> Box { let id = self.id.clone(); let script_chan = self.script_chan.clone(); box move |_, node_address| { let ScriptControlChan(ref chan) = script_chan; debug!("Dirtying {:p}", node_address.0); let mut nodes = SmallVec1::new(); nodes.vec_push(node_address); drop(chan.send(ConstellationControlMsg::SendEvent( id, CompositorEvent::ReflowEvent(nodes)))) } } } impl LayoutTaskFactory for LayoutTask { /// Spawns a new layout task. fn create(_phantom: Option<&mut LayoutTask>, id: PipelineId, url: Url, is_iframe: bool, chan: OpaqueScriptLayoutChannel, pipeline_port: Receiver, constellation_chan: ConstellationChan, failure_msg: Failure, script_chan: ScriptControlChan, paint_chan: PaintChan, resource_task: ResourceTask, img_cache_task: ImageCacheTask, font_cache_task: FontCacheTask, time_profiler_chan: time::ProfilerChan, memory_profiler_chan: mem::ProfilerChan, shutdown_chan: Sender<()>) { let ConstellationChan(con_chan) = constellation_chan.clone(); spawn_named_with_send_on_failure("LayoutTask", task_state::LAYOUT, move || { { // Ensures layout task is destroyed before we send shutdown message let sender = chan.sender(); let layout = LayoutTask::new(id, url, is_iframe, chan.receiver(), LayoutChan(sender), pipeline_port, constellation_chan, script_chan, paint_chan, resource_task, img_cache_task, font_cache_task, time_profiler_chan, memory_profiler_chan); layout.start(); } shutdown_chan.send(()).unwrap(); }, ConstellationMsg::Failure(failure_msg), con_chan); } } /// The `LayoutTask` `rw_data` lock must remain locked until the first reflow, /// as RPC calls don't make sense until then. Use this in combination with /// `LayoutTask::lock_rw_data` and `LayoutTask::return_rw_data`. enum RWGuard<'a> { /// If the lock was previously held, from when the task started. Held(MutexGuard<'a, LayoutTaskData>), /// If the lock was just used, and has been returned since there has been /// a reflow already. Used(MutexGuard<'a, LayoutTaskData>), } impl<'a> Deref for RWGuard<'a> { type Target = LayoutTaskData; fn deref(&self) -> &LayoutTaskData { match *self { RWGuard::Held(ref x) => &**x, RWGuard::Used(ref x) => &**x, } } } impl<'a> DerefMut for RWGuard<'a> { fn deref_mut(&mut self) -> &mut LayoutTaskData { match *self { RWGuard::Held(ref mut x) => &mut **x, RWGuard::Used(ref mut x) => &mut **x, } } } impl LayoutTask { /// Creates a new `LayoutTask` structure. fn new(id: PipelineId, url: Url, is_iframe: bool, port: Receiver, chan: LayoutChan, pipeline_port: Receiver, constellation_chan: ConstellationChan, script_chan: ScriptControlChan, paint_chan: PaintChan, resource_task: ResourceTask, image_cache_task: ImageCacheTask, font_cache_task: FontCacheTask, time_profiler_chan: time::ProfilerChan, mem_profiler_chan: mem::ProfilerChan) -> LayoutTask { let local_image_cache = Arc::new(Mutex::new(LocalImageCache::new(image_cache_task.clone()))); let screen_size = Size2D(Au(0), Au(0)); let device = Device::new( MediaType::Screen, opts::get().initial_window_size.as_f32() * ScaleFactor::new(1.0)); let parallel_traversal = if opts::get().layout_threads != 1 { Some(WorkQueue::new("LayoutWorker", task_state::LAYOUT, opts::get().layout_threads, SharedLayoutContextWrapper(ptr::null()))) } else { None }; // Register this thread as a memory reporter, via its own channel. let reporter = box chan.clone(); let reporter_name = format!("layout-reporter-{}", id.0); mem_profiler_chan.send(mem::ProfilerMsg::RegisterReporter(reporter_name.clone(), reporter)); // Create the channel on which new animations can be sent. let (new_animations_sender, new_animations_receiver) = channel(); LayoutTask { id: id, url: url, is_iframe: is_iframe, port: port, pipeline_port: pipeline_port, chan: chan, script_chan: script_chan, constellation_chan: constellation_chan.clone(), paint_chan: paint_chan, time_profiler_chan: time_profiler_chan, mem_profiler_chan: mem_profiler_chan, reporter_name: reporter_name, resource_task: resource_task, image_cache_task: image_cache_task.clone(), font_cache_task: font_cache_task, first_reflow: Cell::new(true), rw_data: Arc::new(Mutex::new( LayoutTaskData { root_flow: None, local_image_cache: local_image_cache, constellation_chan: constellation_chan, screen_size: screen_size, stacking_context: None, stylist: box Stylist::new(device), parallel_traversal: parallel_traversal, dirty: Rect::zero(), generation: 0, content_box_response: Rect::zero(), content_boxes_response: Vec::new(), running_animations: Vec::new(), new_animations_receiver: new_animations_receiver, new_animations_sender: new_animations_sender, })), } } /// Starts listening on the port. fn start(self) { let mut possibly_locked_rw_data = Some((*self.rw_data).lock().unwrap()); while self.handle_request(&mut possibly_locked_rw_data) { // Loop indefinitely. } } // Create a layout context for use in building display lists, hit testing, &c. fn build_shared_layout_context(&self, rw_data: &LayoutTaskData, screen_size_changed: bool, reflow_root: Option<&LayoutNode>, url: &Url) -> SharedLayoutContext { SharedLayoutContext { image_cache: rw_data.local_image_cache.clone(), screen_size: rw_data.screen_size.clone(), screen_size_changed: screen_size_changed, constellation_chan: rw_data.constellation_chan.clone(), layout_chan: self.chan.clone(), font_cache_task: self.font_cache_task.clone(), stylist: &*rw_data.stylist, url: (*url).clone(), reflow_root: reflow_root.map(|node| OpaqueNodeMethods::from_layout_node(node)), dirty: Rect::zero(), generation: rw_data.generation, new_animations_sender: rw_data.new_animations_sender.clone(), } } /// Receives and dispatches messages from the script and constellation tasks fn handle_request<'a>(&'a self, possibly_locked_rw_data: &mut Option>) -> bool { enum PortToRead { Pipeline, Script, } let port_to_read = { let sel = Select::new(); let mut port1 = sel.handle(&self.port); let mut port2 = sel.handle(&self.pipeline_port); unsafe { port1.add(); port2.add(); } let ret = sel.wait(); if ret == port1.id() { PortToRead::Script } else if ret == port2.id() { PortToRead::Pipeline } else { panic!("invalid select result"); } }; match port_to_read { PortToRead::Pipeline => { match self.pipeline_port.recv().unwrap() { LayoutControlMsg::TickAnimationsMsg => { self.handle_request_helper(Msg::TickAnimations, possibly_locked_rw_data) } LayoutControlMsg::ExitNowMsg(exit_type) => { self.handle_request_helper(Msg::ExitNow(exit_type), possibly_locked_rw_data) } } }, PortToRead::Script => { let msg = self.port.recv().unwrap(); self.handle_request_helper(msg, possibly_locked_rw_data) } } } /// If no reflow has happened yet, this will just return the lock in /// `possibly_locked_rw_data`. Otherwise, it will acquire the `rw_data` lock. /// /// If you do not wish RPCs to remain blocked, just drop the `RWGuard` /// returned from this function. If you _do_ wish for them to remain blocked, /// use `return_rw_data`. fn lock_rw_data<'a>(&'a self, possibly_locked_rw_data: &mut Option>) -> RWGuard<'a> { match possibly_locked_rw_data.take() { None => RWGuard::Used((*self.rw_data).lock().unwrap()), Some(x) => RWGuard::Held(x), } } /// If no reflow has ever been triggered, this will keep the lock, locked /// (and saved in `possibly_locked_rw_data`). If it has been, the lock will /// be unlocked. fn return_rw_data<'a>(possibly_locked_rw_data: &mut Option>, rw_data: RWGuard<'a>) { match rw_data { RWGuard::Used(x) => drop(x), RWGuard::Held(x) => *possibly_locked_rw_data = Some(x), } } /// Receives and dispatches messages from other tasks. fn handle_request_helper<'a>(&'a self, request: Msg, possibly_locked_rw_data: &mut Option>) -> bool { match request { Msg::AddStylesheet(sheet, mq) => { self.handle_add_stylesheet(sheet, mq, possibly_locked_rw_data) } Msg::LoadStylesheet(url, mq) => { self.handle_load_stylesheet(url, mq, possibly_locked_rw_data) } Msg::SetQuirksMode => self.handle_set_quirks_mode(possibly_locked_rw_data), Msg::GetRPC(response_chan) => { response_chan.send(box LayoutRPCImpl(self.rw_data.clone()) as Box).unwrap(); }, Msg::Reflow(data) => { profile(time::ProfilerCategory::LayoutPerform, self.profiler_metadata(), self.time_profiler_chan.clone(), || self.handle_reflow(&*data, possibly_locked_rw_data)); }, Msg::TickAnimations => self.tick_all_animations(possibly_locked_rw_data), Msg::ReapLayoutData(dead_layout_data) => { unsafe { self.handle_reap_layout_data(dead_layout_data) } }, Msg::CollectReports(reports_chan) => { self.collect_reports(reports_chan, possibly_locked_rw_data); }, Msg::PrepareToExit(response_chan) => { debug!("layout: PrepareToExitMsg received"); self.prepare_to_exit(response_chan, possibly_locked_rw_data); return false }, Msg::ExitNow(exit_type) => { debug!("layout: ExitNowMsg received"); self.exit_now(possibly_locked_rw_data, exit_type); return false } } true } fn collect_reports<'a>(&'a self, reports_chan: ReportsChan, possibly_locked_rw_data: &mut Option>) { let mut reports = vec![]; // FIXME(njn): Just measuring the display tree for now. let rw_data = self.lock_rw_data(possibly_locked_rw_data); let stacking_context = rw_data.stacking_context.as_ref(); reports.push(Report { path: path!["pages", format!("url({})", self.url), "display-list"], size: stacking_context.map_or(0, |sc| sc.heap_size_of_children()), }); reports_chan.send(reports); } /// Enters a quiescent state in which no new messages except for /// `layout_interface::Msg::ReapLayoutData` will be processed until an `ExitNowMsg` is /// received. A pong is immediately sent on the given response channel. fn prepare_to_exit<'a>(&'a self, response_chan: Sender<()>, possibly_locked_rw_data: &mut Option>) { response_chan.send(()).unwrap(); loop { match self.port.recv().unwrap() { Msg::ReapLayoutData(dead_layout_data) => { unsafe { self.handle_reap_layout_data(dead_layout_data) } } Msg::ExitNow(exit_type) => { debug!("layout task is exiting..."); self.exit_now(possibly_locked_rw_data, exit_type); break } _ => { panic!("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<'a>(&'a self, possibly_locked_rw_data: &mut Option>, exit_type: PipelineExitType) { let (response_chan, response_port) = channel(); { let mut rw_data = self.lock_rw_data(possibly_locked_rw_data); if let Some(ref mut traversal) = (&mut *rw_data).parallel_traversal { traversal.shutdown() } LayoutTask::return_rw_data(possibly_locked_rw_data, rw_data); } let msg = mem::ProfilerMsg::UnregisterReporter(self.reporter_name.clone()); self.mem_profiler_chan.send(msg); self.paint_chan.send(PaintMsg::Exit(Some(response_chan), exit_type)); response_port.recv().unwrap() } fn handle_load_stylesheet<'a>(&'a self, url: Url, mq: MediaQueryList, possibly_locked_rw_data: &mut Option>) { // TODO: Get the actual value. http://dev.w3.org/csswg/css-syntax/#environment-encoding let environment_encoding = UTF_8 as EncodingRef; // TODO we don't really even need to load this if mq does not match let (metadata, iter) = load_bytes_iter(&self.resource_task, url); let protocol_encoding_label = metadata.charset.as_ref().map(|s| s.as_slice()); let final_url = metadata.final_url; let sheet = Stylesheet::from_bytes_iter(iter, final_url, protocol_encoding_label, Some(environment_encoding), Origin::Author); self.handle_add_stylesheet(sheet, mq, possibly_locked_rw_data); } fn handle_add_stylesheet<'a>(&'a self, sheet: Stylesheet, mq: MediaQueryList, possibly_locked_rw_data: &mut Option>) { // Find all font-face rules and notify the font cache of them. // GWTODO: Need to handle unloading web fonts (when we handle unloading stylesheets!) let mut rw_data = self.lock_rw_data(possibly_locked_rw_data); if mq.evaluate(&rw_data.stylist.device) { for font_face in sheet.effective_rules(&rw_data.stylist.device).font_face() { for source in font_face.sources.iter() { self.font_cache_task.add_web_font(font_face.family.clone(), source.clone()); } } rw_data.stylist.add_stylesheet(sheet); } LayoutTask::return_rw_data(possibly_locked_rw_data, rw_data); } /// Sets quirks mode for the document, causing the quirks mode stylesheet to be loaded. fn handle_set_quirks_mode<'a>(&'a self, possibly_locked_rw_data: &mut Option>) { let mut rw_data = self.lock_rw_data(possibly_locked_rw_data); rw_data.stylist.add_quirks_mode_stylesheet(); LayoutTask::return_rw_data(possibly_locked_rw_data, rw_data); } fn try_get_layout_root(&self, node: LayoutNode) -> Option { let mut layout_data_ref = node.mutate_layout_data(); let layout_data = match layout_data_ref.as_mut() { None => return None, Some(layout_data) => layout_data, }; let result = layout_data.data.flow_construction_result.swap_out(); let mut flow = match result { ConstructionResult::Flow(mut flow, abs_descendants) => { // Note: Assuming that the root has display 'static' (as per // CSS Section 9.3.1). Otherwise, if it were absolutely // positioned, it would return a reference to itself in // `abs_descendants` and would lead to a circular reference. // Set Root as CB for any remaining absolute descendants. flow.set_absolute_descendants(abs_descendants); flow } _ => return None, }; flow.mark_as_root(); Some(flow) } fn get_layout_root(&self, node: LayoutNode) -> FlowRef { self.try_get_layout_root(node).expect("no layout root") } /// 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<'a>(&self, layout_root: &mut FlowRef, shared_layout_context: &SharedLayoutContext) { let _scope = layout_debug_scope!("solve_constraints"); sequential::traverse_flow_tree_preorder(layout_root, shared_layout_context); } /// 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(&self, rw_data: &mut LayoutTaskData, layout_root: &mut FlowRef, shared_layout_context: &SharedLayoutContext) { let _scope = layout_debug_scope!("solve_constraints_parallel"); match rw_data.parallel_traversal { None => panic!("solve_contraints_parallel() called with no parallel traversal ready"), Some(ref mut traversal) => { // NOTE: this currently computes borders, so any pruning should separate that // operation out. parallel::traverse_flow_tree_preorder(layout_root, self.profiler_metadata(), self.time_profiler_chan.clone(), shared_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(&self, layout_root: &mut FlowRef) { let mut traversal = traversal::FlowTreeVerification; layout_root.traverse_preorder(&mut traversal); } #[cfg(not(debug))] fn verify_flow_tree(&self, _: &mut FlowRef) { } fn process_content_box_request<'a>(&'a self, requested_node: TrustedNodeAddress, layout_root: &mut FlowRef, rw_data: &mut RWGuard<'a>) { // FIXME(pcwalton): This has not been updated to handle the stacking context relative // stuff. So the position is wrong in most cases. let requested_node: OpaqueNode = OpaqueNodeMethods::from_script_node(requested_node); let mut iterator = UnioningFragmentBorderBoxIterator::new(requested_node); sequential::iterate_through_flow_tree_fragment_border_boxes(layout_root, &mut iterator); rw_data.content_box_response = match iterator.rect { Some(rect) => rect, None => Rect::zero() }; } fn process_content_boxes_request<'a>(&'a self, requested_node: TrustedNodeAddress, layout_root: &mut FlowRef, rw_data: &mut RWGuard<'a>) { // FIXME(pcwalton): This has not been updated to handle the stacking context relative // stuff. So the position is wrong in most cases. let requested_node: OpaqueNode = OpaqueNodeMethods::from_script_node(requested_node); let mut iterator = CollectingFragmentBorderBoxIterator::new(requested_node); sequential::iterate_through_flow_tree_fragment_border_boxes(layout_root, &mut iterator); rw_data.content_boxes_response = iterator.rects; } fn build_display_list_for_reflow<'a>(&'a self, data: &Reflow, layout_root: &mut FlowRef, shared_layout_context: &mut SharedLayoutContext, rw_data: &mut LayoutTaskData) { let writing_mode = flow::base(&**layout_root).writing_mode; profile(time::ProfilerCategory::LayoutDispListBuild, self.profiler_metadata(), self.time_profiler_chan.clone(), || { shared_layout_context.dirty = flow::base(&**layout_root).position.to_physical(writing_mode, rw_data.screen_size); flow::mut_base(&mut **layout_root).stacking_relative_position = LogicalPoint::zero(writing_mode).to_physical(writing_mode, rw_data.screen_size); flow::mut_base(&mut **layout_root).clip = ClippingRegion::from_rect(&data.page_clip_rect); match rw_data.parallel_traversal { None => { sequential::build_display_list_for_subtree(layout_root, shared_layout_context); } Some(ref mut traversal) => { parallel::build_display_list_for_subtree(layout_root, self.profiler_metadata(), self.time_profiler_chan.clone(), shared_layout_context, traversal); } } debug!("Done building display list."); let root_background_color = get_root_flow_background_color(&mut **layout_root); let root_size = { let root_flow = flow::base(&**layout_root); root_flow.position.size.to_physical(root_flow.writing_mode) }; let mut display_list = box DisplayList::new(); flow::mut_base(&mut **layout_root).display_list_building_result .add_to(&mut *display_list); let paint_layer = Arc::new(PaintLayer::new(layout_root.layer_id(0), root_background_color, ScrollPolicy::Scrollable)); let origin = Rect(Point2D(Au(0), Au(0)), root_size); if opts::get().dump_display_list { println!("#### start printing display list."); display_list.print_items(String::from_str("#")); } let stacking_context = Arc::new(StackingContext::new(display_list, &origin, &origin, 0, &Matrix2D::identity(), filter::T::new(Vec::new()), mix_blend_mode::T::normal, Some(paint_layer))); rw_data.stacking_context = Some(stacking_context.clone()); debug!("Layout done!"); self.paint_chan.send(PaintMsg::PaintInit(stacking_context)); }); } /// The high-level routine that performs layout tasks. fn handle_reflow<'a>(&'a self, data: &ScriptReflow, possibly_locked_rw_data: &mut Option>) { // 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 mut node: LayoutJS = unsafe { LayoutJS::from_trusted_node_address(data.document_root) }; let node: &mut LayoutNode = unsafe { transmute(&mut node) }; debug!("layout: received layout request for: {}", self.url.serialize()); if log_enabled!(log::DEBUG) { node.dump(); } let mut rw_data = self.lock_rw_data(possibly_locked_rw_data); { // Reset the image cache. let mut local_image_cache = rw_data.local_image_cache.lock().unwrap(); local_image_cache.next_round(self.make_on_image_available_cb()); } // TODO: Calculate the "actual viewport": // http://www.w3.org/TR/css-device-adapt/#actual-viewport let viewport_size = data.window_size.initial_viewport; let old_screen_size = rw_data.screen_size; let current_screen_size = Size2D(Au::from_frac32_px(viewport_size.width.get()), Au::from_frac32_px(viewport_size.height.get())); rw_data.screen_size = current_screen_size; // Handle conditions where the entire flow tree is invalid. let screen_size_changed = current_screen_size != old_screen_size; if screen_size_changed { let device = Device::new(MediaType::Screen, data.window_size.initial_viewport); rw_data.stylist.set_device(device); } // If the entire flow tree is invalid, then it will be reflowed anyhow. let needs_dirtying = rw_data.stylist.update(); let needs_reflow = screen_size_changed && !needs_dirtying; unsafe { if needs_dirtying { LayoutTask::dirty_all_nodes(node); } } if needs_reflow { match self.try_get_layout_root(*node) { None => {} Some(mut flow) => { LayoutTask::reflow_all_nodes(&mut *flow); } } } // Create a layout context for use throughout the following passes. let mut shared_layout_context = self.build_shared_layout_context(&*rw_data, screen_size_changed, Some(&node), &self.url); // Recalculate CSS styles and rebuild flows and fragments. profile(time::ProfilerCategory::LayoutStyleRecalc, self.profiler_metadata(), self.time_profiler_chan.clone(), || { // Perform CSS selector matching and flow construction. let rw_data = &mut *rw_data; match rw_data.parallel_traversal { None => { sequential::traverse_dom_preorder(*node, &shared_layout_context); } Some(ref mut traversal) => { parallel::traverse_dom_preorder(*node, &shared_layout_context, traversal); } } }); // Retrieve the (possibly rebuilt) root flow. rw_data.root_flow = Some(self.get_layout_root((*node).clone())); // Kick off animations if any were triggered. animation::process_new_animations(&mut *rw_data, self.id); // Perform post-style recalculation layout passes. self.perform_post_style_recalc_layout_passes(&data.reflow_info, &mut rw_data, &mut shared_layout_context); 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::NoQuery => {} } // 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(()).unwrap(); let ScriptControlChan(ref chan) = data.script_chan; chan.send(ConstellationControlMsg::ReflowComplete(self.id, data.id)).unwrap(); } fn tick_all_animations<'a>(&'a self, possibly_locked_rw_data: &mut Option>) { let mut rw_data = self.lock_rw_data(possibly_locked_rw_data); animation::tick_all_animations(self, &mut rw_data) } pub fn tick_animation<'a>(&'a self, animation: Animation, rw_data: &mut LayoutTaskData) { let reflow_info = Reflow { goal: ReflowGoal::ForDisplay, page_clip_rect: MAX_RECT, }; // Perform an abbreviated style recalc that operates without access to the DOM. let mut layout_context = self.build_shared_layout_context(&*rw_data, false, None, &self.url); let mut root_flow = (*rw_data.root_flow.as_ref().unwrap()).clone(); profile(time::ProfilerCategory::LayoutStyleRecalc, self.profiler_metadata(), self.time_profiler_chan.clone(), || animation::recalc_style_for_animation(root_flow.deref_mut(), &animation)); self.perform_post_style_recalc_layout_passes(&reflow_info, &mut *rw_data, &mut layout_context); } fn perform_post_style_recalc_layout_passes<'a>(&'a self, data: &Reflow, rw_data: &mut LayoutTaskData, layout_context: &mut SharedLayoutContext) { let mut root_flow = (*rw_data.root_flow.as_ref().unwrap()).clone(); profile(time::ProfilerCategory::LayoutRestyleDamagePropagation, self.profiler_metadata(), self.time_profiler_chan.clone(), || { if opts::get().nonincremental_layout || root_flow.deref_mut() .compute_layout_damage() .contains(REFLOW_ENTIRE_DOCUMENT) { root_flow.deref_mut().reflow_entire_document() } }); // 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 root_flow); if opts::get().trace_layout { layout_debug::begin_trace(root_flow.clone()); } // Resolve generated content. profile(time::ProfilerCategory::LayoutGeneratedContent, self.profiler_metadata(), self.time_profiler_chan.clone(), || sequential::resolve_generated_content(&mut root_flow, &layout_context)); // Perform the primary layout passes over the flow tree to compute the locations of all // the boxes. profile(time::ProfilerCategory::LayoutMain, self.profiler_metadata(), self.time_profiler_chan.clone(), || { match rw_data.parallel_traversal { None => { // Sequential mode. self.solve_constraints(&mut root_flow, &layout_context) } Some(_) => { // Parallel mode. self.solve_constraints_parallel(rw_data, &mut root_flow, &mut *layout_context); } } }); // Build the display list if necessary, and send it to the painter. match data.goal { ReflowGoal::ForDisplay => { self.build_display_list_for_reflow(data, &mut root_flow, &mut *layout_context, rw_data); } ReflowGoal::ForScriptQuery => {} } self.first_reflow.set(false); if opts::get().trace_layout { layout_debug::end_trace(); } if opts::get().dump_flow_tree { root_flow.dump(); } rw_data.generation += 1; } unsafe fn dirty_all_nodes(node: &mut LayoutNode) { for node in node.traverse_preorder() { // TODO(cgaebel): mark nodes which are sensitive to media queries as // "changed": // > node.set_changed(true); node.set_dirty(true); node.set_dirty_siblings(true); node.set_dirty_descendants(true); } } fn reflow_all_nodes(flow: &mut Flow) { flow::mut_base(flow).restyle_damage.insert(REFLOW | REPAINT); for child in flow::child_iter(flow) { LayoutTask::reflow_all_nodes(child); } } /// 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. /// /// FIXME(pcwalton): Rewrite all of this. fn make_on_image_available_cb(&self) -> Box+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 box LayoutImageResponder { id: self.id.clone(), script_chan: self.script_chan.clone(), } as Box+Send> } /// Handles a message to destroy layout data. Layout data must be destroyed on *this* task /// because the struct type is transmuted to a different type on the script side. unsafe fn handle_reap_layout_data(&self, layout_data: LayoutData) { let layout_data_wrapper: LayoutDataWrapper = transmute(layout_data); layout_data_wrapper.remove_compositor_layers(self.constellation_chan.clone()); } /// Returns profiling information which is passed to the time profiler. fn profiler_metadata(&self) -> ProfilerMetadata { Some((&self.url, if self.is_iframe { TimerMetadataFrameType::IFrame } else { TimerMetadataFrameType::RootWindow }, if self.first_reflow.get() { TimerMetadataReflowType::FirstReflow } else { TimerMetadataReflowType::Incremental })) } } struct LayoutRPCImpl(Arc>); impl LayoutRPC for LayoutRPCImpl { // 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`. fn content_box(&self) -> ContentBoxResponse { let &LayoutRPCImpl(ref rw_data) = self; let rw_data = rw_data.lock().unwrap(); ContentBoxResponse(rw_data.content_box_response) } /// Requests the dimensions of all the content boxes, as in the `getClientRects()` call. fn content_boxes(&self) -> ContentBoxesResponse { let &LayoutRPCImpl(ref rw_data) = self; let rw_data = rw_data.lock().unwrap(); ContentBoxesResponse(rw_data.content_boxes_response.clone()) } /// Requests the node containing the point of interest. fn hit_test(&self, _: TrustedNodeAddress, point: Point2D) -> Result { let point = Point2D(Au::from_frac_px(point.x as f64), Au::from_frac_px(point.y as f64)); let resp = { let &LayoutRPCImpl(ref rw_data) = self; let rw_data = rw_data.lock().unwrap(); match rw_data.stacking_context { None => panic!("no root stacking context!"), Some(ref stacking_context) => { let mut result = Vec::new(); stacking_context.hit_test(point, &mut result, true); if !result.is_empty() { Some(HitTestResponse(result[0].node.to_untrusted_node_address())) } else { None } } } }; if resp.is_some() { return Ok(resp.unwrap()); } Err(()) } fn mouse_over(&self, _: TrustedNodeAddress, point: Point2D) -> Result { let mut mouse_over_list: Vec = vec!(); let point = Point2D(Au::from_frac_px(point.x as f64), Au::from_frac_px(point.y as f64)); { let &LayoutRPCImpl(ref rw_data) = self; let rw_data = rw_data.lock().unwrap(); match rw_data.stacking_context { None => panic!("no root stacking context!"), Some(ref stacking_context) => { stacking_context.hit_test(point, &mut mouse_over_list, false); } } // Compute the new cursor. let cursor = if !mouse_over_list.is_empty() { mouse_over_list[0].pointing.unwrap() } else { Cursor::DefaultCursor }; let ConstellationChan(ref constellation_chan) = rw_data.constellation_chan; constellation_chan.send(ConstellationMsg::SetCursor(cursor)).unwrap(); } if mouse_over_list.is_empty() { Err(()) } else { let response_list = mouse_over_list.iter() .map(|metadata| metadata.node.to_untrusted_node_address()) .collect(); Ok(MouseOverResponse(response_list)) } } } struct UnioningFragmentBorderBoxIterator { node_address: OpaqueNode, rect: Option>, } impl UnioningFragmentBorderBoxIterator { fn new(node_address: OpaqueNode) -> UnioningFragmentBorderBoxIterator { UnioningFragmentBorderBoxIterator { node_address: node_address, rect: None } } } impl FragmentBorderBoxIterator for UnioningFragmentBorderBoxIterator { fn process(&mut self, _: &Fragment, border_box: &Rect) { self.rect = match self.rect { Some(rect) => { Some(rect.union(border_box)) } None => { Some(*border_box) } }; } fn should_process(&mut self, fragment: &Fragment) -> bool { self.node_address == fragment.node } } struct CollectingFragmentBorderBoxIterator { node_address: OpaqueNode, rects: Vec>, } impl CollectingFragmentBorderBoxIterator { fn new(node_address: OpaqueNode) -> CollectingFragmentBorderBoxIterator { CollectingFragmentBorderBoxIterator { node_address: node_address, rects: Vec::new(), } } } impl FragmentBorderBoxIterator for CollectingFragmentBorderBoxIterator { fn process(&mut self, _: &Fragment, border_box: &Rect) { self.rects.push(*border_box); } fn should_process(&mut self, fragment: &Fragment) -> bool { self.node_address == fragment.node } } // 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 // element (http://dev.w3.org/csswg/css-backgrounds/#special-backgrounds) if // it is non-transparent. The phrase in the spec "If the canvas background // is not opaque, what shows through is UA-dependent." is handled by rust-layers // clearing the frame buffer to white. This ensures that setting a background // color on an iframe element, while the iframe content itself has a default // transparent background color is handled correctly. fn get_root_flow_background_color(flow: &mut Flow) -> AzColor { if !flow.is_block_like() { return color::transparent_black() } let block_flow = flow.as_block(); let kid = match block_flow.base.children.iter_mut().next() { None => return color::transparent_black(), Some(kid) => kid, }; if !kid.is_block_like() { return color::transparent_black() } let kid_block_flow = kid.as_block(); kid_block_flow.fragment .style .resolve_color(kid_block_flow.fragment.style.get_background().background_color) .to_gfx_color() }