/* 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 https://mozilla.org/MPL/2.0/. */ // Work around https://github.com/rust-lang/rust/issues/62132 #![recursion_limit = "128"] //! The layout thread. Performs layout on the DOM, builds display lists and sends them to be //! painted. #[macro_use] extern crate crossbeam_channel; #[macro_use] extern crate html5ever; #[macro_use] extern crate lazy_static; #[macro_use] extern crate log; #[macro_use] extern crate profile_traits; mod dom_wrapper; use crate::dom_wrapper::drop_style_and_layout_data; use crate::dom_wrapper::{ServoLayoutDocument, ServoLayoutElement, ServoLayoutNode}; use app_units::Au; use crossbeam_channel::{unbounded, Receiver, Sender}; use embedder_traits::resources::{self, Resource}; use euclid::{default::Size2D as UntypedSize2D, Point2D, Rect, Scale, Size2D}; use fnv::FnvHashMap; use fxhash::FxHashMap; use gfx::font_cache_thread::FontCacheThread; use gfx::font_context; use gfx_traits::{node_id_from_scroll_id, Epoch}; use ipc_channel::ipc::{self, IpcReceiver, IpcSender}; use ipc_channel::router::ROUTER; use layout::context::LayoutContext; use layout::display_list::DisplayListBuilder; use layout::query::{ process_content_box_request, process_content_boxes_request, LayoutRPCImpl, LayoutThreadData, }; use layout::query::{process_element_inner_text_query, process_node_geometry_request}; use layout::query::{process_node_scroll_area_request, process_node_scroll_id_request}; use layout::query::{ process_offset_parent_query, process_resolved_style_request, process_style_query, process_text_index_request, }; use layout::traversal::RecalcStyle; use layout::BoxTreeRoot; use layout_traits::LayoutThreadFactory; use libc::c_void; use malloc_size_of::{MallocSizeOf, MallocSizeOfOps}; use metrics::{PaintTimeMetrics, ProfilerMetadataFactory, ProgressiveWebMetric}; use msg::constellation_msg::{ BackgroundHangMonitor, BackgroundHangMonitorRegister, HangAnnotation, }; use msg::constellation_msg::{LayoutHangAnnotation, MonitoredComponentType, PipelineId}; use msg::constellation_msg::{MonitoredComponentId, TopLevelBrowsingContextId}; use net_traits::image_cache::ImageCache; use profile_traits::mem::{self as profile_mem, Report, ReportKind, ReportsChan}; use profile_traits::time::{self as profile_time, profile, TimerMetadata}; use profile_traits::time::{TimerMetadataFrameType, TimerMetadataReflowType}; use script_layout_interface::message::{LayoutThreadInit, Msg, NodesFromPointQueryType}; use script_layout_interface::message::{QueryMsg, ReflowComplete, ReflowGoal, ScriptReflow}; use script_layout_interface::rpc::TextIndexResponse; use script_layout_interface::rpc::{LayoutRPC, OffsetParentResponse, StyleResponse}; use script_traits::Painter; use script_traits::{ConstellationControlMsg, LayoutControlMsg, LayoutMsg as ConstellationMsg}; use script_traits::{DrawAPaintImageResult, PaintWorkletError}; use script_traits::{ScrollState, UntrustedNodeAddress}; use selectors::Element; use servo_arc::Arc as ServoArc; use servo_atoms::Atom; use servo_config::opts; use servo_config::pref; use servo_geometry::DeviceIndependentPixel; use servo_url::ServoUrl; use std::cell::{Cell, RefCell}; use std::collections::HashMap; use std::ops::{Deref, DerefMut}; use std::process; use std::sync::atomic::{AtomicBool, AtomicUsize, Ordering}; use std::sync::{Arc, Mutex, MutexGuard}; use std::thread; use std::time::Duration; use style::animation::Animation; use style::context::{QuirksMode, RegisteredSpeculativePainter, RegisteredSpeculativePainters}; use style::context::{SharedStyleContext, ThreadLocalStyleContextCreationInfo}; use style::dom::{TDocument, TElement, TNode}; use style::driver; use style::error_reporting::RustLogReporter; use style::global_style_data::GLOBAL_STYLE_DATA; use style::invalidation::element::restyle_hints::RestyleHint; use style::media_queries::{Device, MediaList, MediaType}; use style::properties::PropertyId; use style::selector_parser::SnapshotMap; use style::shared_lock::{SharedRwLock, SharedRwLockReadGuard, StylesheetGuards}; use style::stylesheets::{ DocumentStyleSheet, Origin, Stylesheet, StylesheetInDocument, UserAgentStylesheets, }; use style::stylist::Stylist; use style::thread_state::{self, ThreadState}; use style::timer::Timer; use style::traversal::DomTraversal; use style::traversal_flags::TraversalFlags; use style_traits::CSSPixel; use style_traits::DevicePixel; use style_traits::SpeculativePainter; /// Information needed by the layout thread. pub struct LayoutThread { /// The ID of the pipeline that we belong to. id: PipelineId, /// The ID of the top-level browsing context that we belong to. top_level_browsing_context_id: TopLevelBrowsingContextId, /// The URL of the pipeline that we belong to. url: ServoUrl, /// Performs CSS selector matching and style resolution. stylist: Stylist, /// Is the current reflow of an iframe, as opposed to a root window? is_iframe: bool, /// The port on which we receive messages from the script thread. port: Receiver, /// The port on which we receive messages from the constellation. pipeline_port: Receiver, /// The port on which we receive messages from the font cache thread. font_cache_receiver: Receiver<()>, /// The channel on which the font cache can send messages to us. font_cache_sender: IpcSender<()>, /// A means of communication with the background hang monitor. background_hang_monitor: Box, /// The channel on which messages can be sent to the script thread. script_chan: IpcSender, /// The channel on which messages can be sent to the time profiler. time_profiler_chan: profile_time::ProfilerChan, /// The channel on which messages can be sent to the memory profiler. mem_profiler_chan: profile_mem::ProfilerChan, /// Public interface to the font cache thread. font_cache_thread: FontCacheThread, /// Is this the first reflow in this LayoutThread? first_reflow: Cell, /// Starts at zero, and increased by one every time a layout completes. /// This can be used to easily check for invalid stale data. generation: Cell, /// A channel on which new animations that have been triggered by style recalculation can be /// sent. new_animations_sender: Sender, /// Receives newly-discovered animations. _new_animations_receiver: Receiver, /// The number of Web fonts that have been requested but not yet loaded. outstanding_web_fonts: Arc, /// The root of the box tree. box_tree_root: RefCell>, /// The root of the fragment tree. fragment_tree_root: RefCell>, /// The document-specific shared lock used for author-origin stylesheets document_shared_lock: Option, /// A counter for epoch messages epoch: Cell, /// The size of the viewport. This may be different from the size of the screen due to viewport /// constraints. viewport_size: UntypedSize2D, /// A mutex to allow for fast, read-only RPC of layout's internal data /// structures, while still letting the LayoutThread modify them. /// /// All the other elements of this struct are read-only. rw_data: Arc>, /// The executors for paint worklets. registered_painters: RegisteredPaintersImpl, /// Webrender interface. webrender_api: webrender_api::RenderApi, /// Webrender document. webrender_document: webrender_api::DocumentId, /// The timer object to control the timing of the animations. This should /// only be a test-mode timer during testing for animations. timer: Timer, /// Paint time metrics. paint_time_metrics: PaintTimeMetrics, /// Flag that indicates if LayoutThread is busy handling a request. busy: Arc, /// Load web fonts synchronously to avoid non-deterministic network-driven reflows. load_webfonts_synchronously: bool, /// The initial request size of the window initial_window_size: Size2D, /// The ratio of device pixels per px at the default scale. /// If unspecified, will use the platform default setting. device_pixels_per_px: Option, /// Emits notifications when there is a relayout. relayout_event: bool, } impl LayoutThreadFactory for LayoutThread { type Message = Msg; /// Spawns a new layout thread. fn create( id: PipelineId, top_level_browsing_context_id: TopLevelBrowsingContextId, url: ServoUrl, is_iframe: bool, chan: (Sender, Receiver), pipeline_port: IpcReceiver, background_hang_monitor_register: Box, constellation_chan: IpcSender, script_chan: IpcSender, _image_cache: Arc, font_cache_thread: FontCacheThread, time_profiler_chan: profile_time::ProfilerChan, mem_profiler_chan: profile_mem::ProfilerChan, webrender_api_sender: webrender_api::RenderApiSender, webrender_document: webrender_api::DocumentId, paint_time_metrics: PaintTimeMetrics, busy: Arc, load_webfonts_synchronously: bool, initial_window_size: Size2D, device_pixels_per_px: Option, _dump_display_list: bool, _dump_display_list_json: bool, _dump_style_tree: bool, _dump_rule_tree: bool, relayout_event: bool, _nonincremental_layout: bool, _trace_layout: bool, _dump_flow_tree: bool, ) { thread::Builder::new() .name(format!("LayoutThread {:?}", id)) .spawn(move || { thread_state::initialize(ThreadState::LAYOUT); // In order to get accurate crash reports, we install the top-level bc id. TopLevelBrowsingContextId::install(top_level_browsing_context_id); { // Ensures layout thread is destroyed before we send shutdown message let sender = chan.0; let background_hang_monitor = background_hang_monitor_register .register_component( MonitoredComponentId(id, MonitoredComponentType::Layout), Duration::from_millis(1000), Duration::from_millis(5000), ); let layout = LayoutThread::new( id, top_level_browsing_context_id, url, is_iframe, chan.1, pipeline_port, background_hang_monitor, constellation_chan, script_chan, font_cache_thread, time_profiler_chan, mem_profiler_chan.clone(), webrender_api_sender, webrender_document, paint_time_metrics, busy, load_webfonts_synchronously, initial_window_size, device_pixels_per_px, relayout_event, ); let reporter_name = format!("layout-reporter-{}", id); mem_profiler_chan.run_with_memory_reporting( || { layout.start(); }, reporter_name, sender, Msg::CollectReports, ); } }) .expect("Thread spawning failed"); } } struct ScriptReflowResult { script_reflow: ScriptReflow, result: RefCell>, } impl Deref for ScriptReflowResult { type Target = ScriptReflow; fn deref(&self) -> &ScriptReflow { &self.script_reflow } } impl DerefMut for ScriptReflowResult { fn deref_mut(&mut self) -> &mut Self::Target { &mut self.script_reflow } } impl ScriptReflowResult { fn new(script_reflow: ScriptReflow) -> ScriptReflowResult { ScriptReflowResult { script_reflow: script_reflow, result: RefCell::new(Some(Default::default())), } } } impl Drop for ScriptReflowResult { fn drop(&mut self) { self.script_reflow .script_join_chan .send(self.result.borrow_mut().take().unwrap()) .unwrap(); } } /// The `LayoutThread` `rw_data` lock must remain locked until the first reflow, /// as RPC calls don't make sense until then. Use this in combination with /// `LayoutThread::lock_rw_data` and `LayoutThread::return_rw_data`. pub enum RWGuard<'a> { /// If the lock was previously held, from when the thread started. Held(MutexGuard<'a, LayoutThreadData>), /// If the lock was just used, and has been returned since there has been /// a reflow already. Used(MutexGuard<'a, LayoutThreadData>), } impl<'a> Deref for RWGuard<'a> { type Target = LayoutThreadData; fn deref(&self) -> &LayoutThreadData { match *self { RWGuard::Held(ref x) => &**x, RWGuard::Used(ref x) => &**x, } } } impl<'a> DerefMut for RWGuard<'a> { fn deref_mut(&mut self) -> &mut LayoutThreadData { match *self { RWGuard::Held(ref mut x) => &mut **x, RWGuard::Used(ref mut x) => &mut **x, } } } struct RwData<'a, 'b: 'a> { rw_data: &'b Arc>, possibly_locked_rw_data: &'a mut Option>, } impl<'a, 'b: 'a> RwData<'a, 'b> { /// 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 `block`. fn lock(&mut self) -> RWGuard<'b> { match self.possibly_locked_rw_data.take() { None => RWGuard::Used(self.rw_data.lock().unwrap()), Some(x) => RWGuard::Held(x), } } } fn add_font_face_rules( stylesheet: &Stylesheet, guard: &SharedRwLockReadGuard, device: &Device, font_cache_thread: &FontCacheThread, font_cache_sender: &IpcSender<()>, outstanding_web_fonts_counter: &Arc, load_webfonts_synchronously: bool, ) { if load_webfonts_synchronously { let (sender, receiver) = ipc::channel().unwrap(); stylesheet.effective_font_face_rules(&device, guard, |rule| { if let Some(font_face) = rule.font_face() { let effective_sources = font_face.effective_sources(); font_cache_thread.add_web_font( font_face.family().clone(), effective_sources, sender.clone(), ); receiver.recv().unwrap(); } }) } else { stylesheet.effective_font_face_rules(&device, guard, |rule| { if let Some(font_face) = rule.font_face() { let effective_sources = font_face.effective_sources(); outstanding_web_fonts_counter.fetch_add(1, Ordering::SeqCst); font_cache_thread.add_web_font( font_face.family().clone(), effective_sources, (*font_cache_sender).clone(), ); } }) } } impl LayoutThread { /// Creates a new `LayoutThread` structure. fn new( id: PipelineId, top_level_browsing_context_id: TopLevelBrowsingContextId, url: ServoUrl, is_iframe: bool, port: Receiver, pipeline_port: IpcReceiver, background_hang_monitor: Box, constellation_chan: IpcSender, script_chan: IpcSender, font_cache_thread: FontCacheThread, time_profiler_chan: profile_time::ProfilerChan, mem_profiler_chan: profile_mem::ProfilerChan, webrender_api_sender: webrender_api::RenderApiSender, webrender_document: webrender_api::DocumentId, paint_time_metrics: PaintTimeMetrics, busy: Arc, load_webfonts_synchronously: bool, initial_window_size: Size2D, device_pixels_per_px: Option, relayout_event: bool, ) -> LayoutThread { // The device pixel ratio is incorrect (it does not have the hidpi value), // but it will be set correctly when the initial reflow takes place. let device = Device::new( MediaType::screen(), initial_window_size.to_f32() * Scale::new(1.0), Scale::new(device_pixels_per_px.unwrap_or(1.0)), ); // Create the channel on which new animations can be sent. let (new_animations_sender, new_animations_receiver) = unbounded(); // Proxy IPC messages from the pipeline to the layout thread. let pipeline_receiver = ROUTER.route_ipc_receiver_to_new_crossbeam_receiver(pipeline_port); // Ask the router to proxy IPC messages from the font cache thread to the layout thread. let (ipc_font_cache_sender, ipc_font_cache_receiver) = ipc::channel().unwrap(); let font_cache_receiver = ROUTER.route_ipc_receiver_to_new_crossbeam_receiver(ipc_font_cache_receiver); LayoutThread { id: id, top_level_browsing_context_id: top_level_browsing_context_id, url: url, is_iframe: is_iframe, port: port, pipeline_port: pipeline_receiver, script_chan: script_chan.clone(), background_hang_monitor, time_profiler_chan: time_profiler_chan, mem_profiler_chan: mem_profiler_chan, registered_painters: RegisteredPaintersImpl(Default::default()), font_cache_thread: font_cache_thread, first_reflow: Cell::new(true), font_cache_receiver: font_cache_receiver, font_cache_sender: ipc_font_cache_sender, generation: Cell::new(0), new_animations_sender: new_animations_sender, _new_animations_receiver: new_animations_receiver, outstanding_web_fonts: Arc::new(AtomicUsize::new(0)), box_tree_root: Default::default(), fragment_tree_root: Default::default(), document_shared_lock: None, epoch: Cell::new(Epoch(0)), viewport_size: Size2D::new(Au(0), Au(0)), webrender_api: webrender_api_sender.create_api(), webrender_document, stylist: Stylist::new(device, QuirksMode::NoQuirks), rw_data: Arc::new(Mutex::new(LayoutThreadData { constellation_chan: constellation_chan, display_list: None, content_box_response: None, content_boxes_response: Vec::new(), client_rect_response: Rect::zero(), scroll_id_response: None, scroll_area_response: Rect::zero(), resolved_style_response: String::new(), offset_parent_response: OffsetParentResponse::empty(), style_response: StyleResponse(None), scroll_offsets: HashMap::new(), text_index_response: TextIndexResponse(None), nodes_from_point_response: vec![], element_inner_text_response: String::new(), })), timer: if pref!(layout.animations.test.enabled) { Timer::test_mode() } else { Timer::new() }, paint_time_metrics: paint_time_metrics, busy, load_webfonts_synchronously, initial_window_size, device_pixels_per_px, relayout_event, } } /// Starts listening on the port. fn start(mut self) { let rw_data = self.rw_data.clone(); let mut possibly_locked_rw_data = Some(rw_data.lock().unwrap()); let mut rw_data = RwData { rw_data: &rw_data, possibly_locked_rw_data: &mut possibly_locked_rw_data, }; while self.handle_request(&mut rw_data) { // Loop indefinitely. } } // Create a layout context for use in building display lists, hit testing, &c. fn build_layout_context<'a>( &'a self, guards: StylesheetGuards<'a>, snapshot_map: &'a SnapshotMap, ) -> LayoutContext<'a> { let thread_local_style_context_creation_data = ThreadLocalStyleContextCreationInfo::new(self.new_animations_sender.clone()); LayoutContext { id: self.id, style_context: SharedStyleContext { stylist: &self.stylist, options: GLOBAL_STYLE_DATA.options.clone(), guards, visited_styles_enabled: false, running_animations: Default::default(), expired_animations: Default::default(), registered_speculative_painters: &self.registered_painters, local_context_creation_data: Mutex::new(thread_local_style_context_creation_data), timer: self.timer.clone(), traversal_flags: TraversalFlags::empty(), snapshot_map: snapshot_map, }, font_cache_thread: Mutex::new(self.font_cache_thread.clone()), } } fn notify_activity_to_hang_monitor(&self, request: &Msg) { let hang_annotation = match request { Msg::AddStylesheet(..) => LayoutHangAnnotation::AddStylesheet, Msg::RemoveStylesheet(..) => LayoutHangAnnotation::RemoveStylesheet, Msg::SetQuirksMode(..) => LayoutHangAnnotation::SetQuirksMode, Msg::Reflow(..) => LayoutHangAnnotation::Reflow, Msg::GetRPC(..) => LayoutHangAnnotation::GetRPC, Msg::TickAnimations => LayoutHangAnnotation::TickAnimations, Msg::AdvanceClockMs(..) => LayoutHangAnnotation::AdvanceClockMs, Msg::ReapStyleAndLayoutData(..) => LayoutHangAnnotation::ReapStyleAndLayoutData, Msg::CollectReports(..) => LayoutHangAnnotation::CollectReports, Msg::PrepareToExit(..) => LayoutHangAnnotation::PrepareToExit, Msg::ExitNow => LayoutHangAnnotation::ExitNow, Msg::GetCurrentEpoch(..) => LayoutHangAnnotation::GetCurrentEpoch, Msg::GetWebFontLoadState(..) => LayoutHangAnnotation::GetWebFontLoadState, Msg::CreateLayoutThread(..) => LayoutHangAnnotation::CreateLayoutThread, Msg::SetFinalUrl(..) => LayoutHangAnnotation::SetFinalUrl, Msg::SetScrollStates(..) => LayoutHangAnnotation::SetScrollStates, Msg::UpdateScrollStateFromScript(..) => { LayoutHangAnnotation::UpdateScrollStateFromScript }, Msg::RegisterPaint(..) => LayoutHangAnnotation::RegisterPaint, Msg::SetNavigationStart(..) => LayoutHangAnnotation::SetNavigationStart, Msg::GetRunningAnimations(..) => LayoutHangAnnotation::GetRunningAnimations, }; self.background_hang_monitor .notify_activity(HangAnnotation::Layout(hang_annotation)); } /// Receives and dispatches messages from the script and constellation threads fn handle_request<'a, 'b>(&mut self, possibly_locked_rw_data: &mut RwData<'a, 'b>) -> bool { enum Request { FromPipeline(LayoutControlMsg), FromScript(Msg), FromFontCache, } // Notify the background-hang-monitor we are waiting for an event. self.background_hang_monitor.notify_wait(); let request = select! { recv(self.pipeline_port) -> msg => Request::FromPipeline(msg.unwrap()), recv(self.port) -> msg => Request::FromScript(msg.unwrap()), recv(self.font_cache_receiver) -> msg => { msg.unwrap(); Request::FromFontCache } }; self.busy.store(true, Ordering::Relaxed); let result = match request { Request::FromPipeline(LayoutControlMsg::SetScrollStates(new_scroll_states)) => self .handle_request_helper( Msg::SetScrollStates(new_scroll_states), possibly_locked_rw_data, ), Request::FromPipeline(LayoutControlMsg::TickAnimations) => { self.handle_request_helper(Msg::TickAnimations, possibly_locked_rw_data) }, Request::FromPipeline(LayoutControlMsg::GetCurrentEpoch(sender)) => { self.handle_request_helper(Msg::GetCurrentEpoch(sender), possibly_locked_rw_data) }, Request::FromPipeline(LayoutControlMsg::GetWebFontLoadState(sender)) => self .handle_request_helper(Msg::GetWebFontLoadState(sender), possibly_locked_rw_data), Request::FromPipeline(LayoutControlMsg::ExitNow) => { self.handle_request_helper(Msg::ExitNow, possibly_locked_rw_data) }, Request::FromPipeline(LayoutControlMsg::PaintMetric(epoch, paint_time)) => { self.paint_time_metrics.maybe_set_metric(epoch, paint_time); true }, Request::FromScript(msg) => self.handle_request_helper(msg, possibly_locked_rw_data), Request::FromFontCache => { let _rw_data = possibly_locked_rw_data.lock(); self.outstanding_web_fonts.fetch_sub(1, Ordering::SeqCst); font_context::invalidate_font_caches(); self.script_chan .send(ConstellationControlMsg::WebFontLoaded(self.id)) .unwrap(); true }, }; self.busy.store(false, Ordering::Relaxed); result } /// Receives and dispatches messages from other threads. fn handle_request_helper<'a, 'b>( &mut self, request: Msg, possibly_locked_rw_data: &mut RwData<'a, 'b>, ) -> bool { self.notify_activity_to_hang_monitor(&request); match request { Msg::AddStylesheet(stylesheet, before_stylesheet) => { let guard = stylesheet.shared_lock.read(); self.handle_add_stylesheet(&stylesheet, &guard); match before_stylesheet { Some(insertion_point) => self.stylist.insert_stylesheet_before( DocumentStyleSheet(stylesheet.clone()), DocumentStyleSheet(insertion_point), &guard, ), None => self .stylist .append_stylesheet(DocumentStyleSheet(stylesheet.clone()), &guard), } }, Msg::RemoveStylesheet(stylesheet) => { let guard = stylesheet.shared_lock.read(); self.stylist .remove_stylesheet(DocumentStyleSheet(stylesheet.clone()), &guard); }, Msg::SetQuirksMode(mode) => self.handle_set_quirks_mode(mode), Msg::GetRPC(response_chan) => { response_chan .send(Box::new(LayoutRPCImpl(self.rw_data.clone())) as Box) .unwrap(); }, Msg::Reflow(data) => { let mut data = ScriptReflowResult::new(data); profile( profile_time::ProfilerCategory::LayoutPerform, self.profiler_metadata(), self.time_profiler_chan.clone(), || self.handle_reflow(&mut data, possibly_locked_rw_data), ); }, Msg::TickAnimations => self.tick_all_animations(), Msg::SetScrollStates(new_scroll_states) => { self.set_scroll_states(new_scroll_states, possibly_locked_rw_data); }, Msg::UpdateScrollStateFromScript(state) => { let mut rw_data = possibly_locked_rw_data.lock(); rw_data .scroll_offsets .insert(state.scroll_id, state.scroll_offset); let point = Point2D::new(-state.scroll_offset.x, -state.scroll_offset.y); let mut txn = webrender_api::Transaction::new(); txn.scroll_node_with_id( webrender_api::units::LayoutPoint::from_untyped(point), state.scroll_id, webrender_api::ScrollClamping::ToContentBounds, ); self.webrender_api .send_transaction(self.webrender_document, txn); }, Msg::ReapStyleAndLayoutData(dead_data) => unsafe { drop_style_and_layout_data(dead_data) }, Msg::CollectReports(reports_chan) => { self.collect_reports(reports_chan, possibly_locked_rw_data); }, Msg::GetCurrentEpoch(sender) => { let _rw_data = possibly_locked_rw_data.lock(); sender.send(self.epoch.get()).unwrap(); }, Msg::AdvanceClockMs(how_many, do_tick) => { self.handle_advance_clock_ms(how_many, do_tick); }, Msg::GetWebFontLoadState(sender) => { let _rw_data = possibly_locked_rw_data.lock(); let outstanding_web_fonts = self.outstanding_web_fonts.load(Ordering::SeqCst); sender.send(outstanding_web_fonts != 0).unwrap(); }, Msg::CreateLayoutThread(info) => self.create_layout_thread(info), Msg::SetFinalUrl(final_url) => { self.url = final_url; }, Msg::RegisterPaint(_name, _properties, _painter) => {}, Msg::PrepareToExit(response_chan) => { self.prepare_to_exit(response_chan); return false; }, // Receiving the Exit message at this stage only happens when layout is undergoing a "force exit". Msg::ExitNow => { debug!("layout: ExitNow received"); self.exit_now(); return false; }, Msg::SetNavigationStart(time) => { self.paint_time_metrics.set_navigation_start(time); }, Msg::GetRunningAnimations(sender) => { let _ = sender.send(0); }, } true } fn collect_reports<'a, 'b>( &self, reports_chan: ReportsChan, possibly_locked_rw_data: &mut RwData<'a, 'b>, ) { let mut reports = vec![]; // Servo uses vanilla jemalloc, which doesn't have a // malloc_enclosing_size_of function. let mut ops = MallocSizeOfOps::new(servo_allocator::usable_size, None, None); // FIXME(njn): Just measuring the display tree for now. let rw_data = possibly_locked_rw_data.lock(); let display_list = rw_data.display_list.as_ref(); let formatted_url = &format!("url({})", self.url); reports.push(Report { path: path![formatted_url, "layout-thread", "display-list"], kind: ReportKind::ExplicitJemallocHeapSize, size: display_list.map_or(0, |sc| sc.size_of(&mut ops)), }); reports.push(Report { path: path![formatted_url, "layout-thread", "stylist"], kind: ReportKind::ExplicitJemallocHeapSize, size: self.stylist.size_of(&mut ops), }); reports_chan.send(reports); } fn create_layout_thread(&self, info: LayoutThreadInit) { LayoutThread::create( info.id, self.top_level_browsing_context_id, info.url.clone(), info.is_parent, info.layout_pair, info.pipeline_port, info.background_hang_monitor_register, info.constellation_chan, info.script_chan.clone(), info.image_cache.clone(), self.font_cache_thread.clone(), self.time_profiler_chan.clone(), self.mem_profiler_chan.clone(), self.webrender_api.clone_sender(), self.webrender_document, info.paint_time_metrics, info.layout_is_busy, self.load_webfonts_synchronously, self.initial_window_size, self.device_pixels_per_px, false, // dump_display_list false, // dump_display_list_json false, // dump_style_tree false, // dump_rule_tree self.relayout_event, true, // nonincremental_layout false, // trace_layout false, // dump_flow_tree ); } /// Enters a quiescent state in which no new messages will be processed until an `ExitNow` is /// received. A pong is immediately sent on the given response channel. fn prepare_to_exit(&mut self, response_chan: Sender<()>) { response_chan.send(()).unwrap(); loop { match self.port.recv().unwrap() { Msg::ReapStyleAndLayoutData(dead_data) => unsafe { drop_style_and_layout_data(dead_data) }, Msg::ExitNow => { debug!("layout thread is exiting..."); self.exit_now(); break; }, Msg::CollectReports(_) => { // Just ignore these messages at this point. }, _ => panic!("layout: unexpected message received after `PrepareToExitMsg`"), } } } fn exit_now(&mut self) { self.background_hang_monitor.unregister(); } fn handle_add_stylesheet(&self, stylesheet: &Stylesheet, guard: &SharedRwLockReadGuard) { // Find all font-face rules and notify the font cache of them. // GWTODO: Need to handle unloading web fonts. if stylesheet.is_effective_for_device(self.stylist.device(), &guard) { add_font_face_rules( &*stylesheet, &guard, self.stylist.device(), &self.font_cache_thread, &self.font_cache_sender, &self.outstanding_web_fonts, self.load_webfonts_synchronously, ); } } /// Advances the animation clock of the document. fn handle_advance_clock_ms<'a, 'b>(&mut self, how_many_ms: i32, tick_animations: bool) { self.timer.increment(how_many_ms as f64 / 1000.0); if tick_animations { self.tick_all_animations(); } } /// Sets quirks mode for the document, causing the quirks mode stylesheet to be used. fn handle_set_quirks_mode<'a, 'b>(&mut self, quirks_mode: QuirksMode) { self.stylist.set_quirks_mode(quirks_mode); } /// The high-level routine that performs layout threads. fn handle_reflow<'a, 'b>( &mut self, data: &mut ScriptReflowResult, possibly_locked_rw_data: &mut RwData<'a, 'b>, ) { let document = unsafe { ServoLayoutNode::new(&data.document) }; let document = document.as_document().unwrap(); let mut rw_data = possibly_locked_rw_data.lock(); let element = match document.root_element() { None => { // Since we cannot compute anything, give spec-required placeholders. debug!("layout: No root node: bailing"); match data.reflow_goal { ReflowGoal::LayoutQuery(ref query_msg, _) => match query_msg { &QueryMsg::ContentBoxQuery(_) => { rw_data.content_box_response = None; }, &QueryMsg::ContentBoxesQuery(_) => { rw_data.content_boxes_response = Vec::new(); }, &QueryMsg::NodesFromPointQuery(..) => { rw_data.nodes_from_point_response = Vec::new(); }, &QueryMsg::NodeGeometryQuery(_) => { rw_data.client_rect_response = Rect::zero(); }, &QueryMsg::NodeScrollGeometryQuery(_) => { rw_data.scroll_area_response = Rect::zero(); }, &QueryMsg::NodeScrollIdQuery(_) => { rw_data.scroll_id_response = None; }, &QueryMsg::ResolvedStyleQuery(_, _, _) => { rw_data.resolved_style_response = String::new(); }, &QueryMsg::OffsetParentQuery(_) => { rw_data.offset_parent_response = OffsetParentResponse::empty(); }, &QueryMsg::StyleQuery(_) => { rw_data.style_response = StyleResponse(None); }, &QueryMsg::TextIndexQuery(..) => { rw_data.text_index_response = TextIndexResponse(None); }, &QueryMsg::ElementInnerTextQuery(_) => { rw_data.element_inner_text_response = String::new(); }, }, ReflowGoal::Full | ReflowGoal::TickAnimations => {}, } return; }, Some(x) => x, }; let initial_viewport = data.window_size.initial_viewport; let device_pixel_ratio = data.window_size.device_pixel_ratio; let old_viewport_size = self.viewport_size; let current_screen_size = Size2D::new( Au::from_f32_px(initial_viewport.width), Au::from_f32_px(initial_viewport.height), ); // Calculate the actual viewport as per DEVICE-ADAPT ยง 6 // If the entire flow tree is invalid, then it will be reflowed anyhow. let document_shared_lock = document.style_shared_lock(); self.document_shared_lock = Some(document_shared_lock.clone()); let author_guard = document_shared_lock.read(); let ua_stylesheets = &*UA_STYLESHEETS; let ua_or_user_guard = ua_stylesheets.shared_lock.read(); let guards = StylesheetGuards { author: &author_guard, ua_or_user: &ua_or_user_guard, }; let had_used_viewport_units = self.stylist.device().used_viewport_units(); let device = Device::new(MediaType::screen(), initial_viewport, device_pixel_ratio); let sheet_origins_affected_by_device_change = self.stylist.set_device(device, &guards); self.stylist .force_stylesheet_origins_dirty(sheet_origins_affected_by_device_change); self.viewport_size = self.stylist .viewport_constraints() .map_or(current_screen_size, |constraints| { Size2D::new( Au::from_f32_px(constraints.size.width), Au::from_f32_px(constraints.size.height), ) }); let viewport_size_changed = self.viewport_size != old_viewport_size; if viewport_size_changed { if let Some(constraints) = self.stylist.viewport_constraints() { // let the constellation know about the viewport constraints rw_data .constellation_chan .send(ConstellationMsg::ViewportConstrained( self.id, constraints.clone(), )) .unwrap(); } if had_used_viewport_units { if let Some(mut data) = element.mutate_data() { data.hint.insert(RestyleHint::recascade_subtree()); } } } if self.first_reflow.get() { for stylesheet in &ua_stylesheets.user_or_user_agent_stylesheets { self.stylist .append_stylesheet(stylesheet.clone(), &ua_or_user_guard); self.handle_add_stylesheet(&stylesheet.0, &ua_or_user_guard); } if self.stylist.quirks_mode() != QuirksMode::NoQuirks { self.stylist.append_stylesheet( ua_stylesheets.quirks_mode_stylesheet.clone(), &ua_or_user_guard, ); self.handle_add_stylesheet( &ua_stylesheets.quirks_mode_stylesheet.0, &ua_or_user_guard, ); } } if data.stylesheets_changed { self.stylist .force_stylesheet_origins_dirty(Origin::Author.into()); } // Flush shadow roots stylesheets if dirty. document.flush_shadow_roots_stylesheets( &self.stylist.device(), document.quirks_mode(), guards.author.clone(), ); let restyles = document.drain_pending_restyles(); let mut map = SnapshotMap::new(); let elements_with_snapshot: Vec<_> = restyles .iter() .filter(|r| r.1.snapshot.is_some()) .map(|r| r.0) .collect(); for (el, restyle) in restyles { // Propagate the descendant bit up the ancestors. Do this before // the restyle calculation so that we can also do it for new // unstyled nodes, which the descendants bit helps us find. if let Some(parent) = el.parent_element() { unsafe { parent.note_dirty_descendant() }; } // If we haven't styled this node yet, we don't need to track a // restyle. let style_data = match el.get_data() { Some(d) => d, None => { unsafe { el.unset_snapshot_flags() }; continue; }, }; if let Some(s) = restyle.snapshot { unsafe { el.set_has_snapshot() }; map.insert(el.as_node().opaque(), s); } let mut style_data = style_data.borrow_mut(); // Stash the data on the element for processing by the style system. style_data.hint.insert(restyle.hint.into()); style_data.damage = restyle.damage; debug!("Noting restyle for {:?}: {:?}", el, style_data); } self.stylist.flush(&guards, Some(element), Some(&map)); // Create a layout context for use throughout the following passes. let mut layout_context = self.build_layout_context(guards.clone(), &map); let traversal = RecalcStyle::new(layout_context); let token = { let shared = DomTraversal::::shared_context(&traversal); RecalcStyle::pre_traverse(element, shared) }; if token.should_traverse() { driver::traverse_dom(&traversal, token, None); let shared = DomTraversal::::shared_context(&traversal); let box_tree = BoxTreeRoot::construct(shared, document.root_element().unwrap().as_node()); let fragment_tree = box_tree.layout(Size2D::new( self.viewport_size.width.to_f32_px(), self.viewport_size.height.to_f32_px(), )); *self.box_tree_root.borrow_mut() = Some(box_tree); *self.fragment_tree_root.borrow_mut() = Some(fragment_tree); } for element in elements_with_snapshot { unsafe { element.unset_snapshot_flags() } } layout_context = traversal.destroy(); // GC the rule tree if some heuristics are met. unsafe { layout_context.style_context.stylist.rule_tree().maybe_gc(); } // Perform post-style recalculation layout passes. if let Some(root) = &*self.fragment_tree_root.borrow() { self.perform_post_style_recalc_layout_passes(root, &data.reflow_goal, Some(&document)); } self.first_reflow.set(false); self.respond_to_query_if_necessary(&data.reflow_goal, &mut *rw_data, &mut layout_context); } fn respond_to_query_if_necessary( &self, reflow_goal: &ReflowGoal, rw_data: &mut LayoutThreadData, context: &mut LayoutContext, ) { match *reflow_goal { ReflowGoal::LayoutQuery(ref querymsg, _) => match querymsg { &QueryMsg::ContentBoxQuery(node) => { rw_data.content_box_response = process_content_box_request(node); }, &QueryMsg::ContentBoxesQuery(node) => { rw_data.content_boxes_response = process_content_boxes_request(node); }, &QueryMsg::TextIndexQuery(node, point_in_node) => { let point_in_node = Point2D::new( Au::from_f32_px(point_in_node.x), Au::from_f32_px(point_in_node.y), ); rw_data.text_index_response = process_text_index_request(node, point_in_node); }, &QueryMsg::NodeGeometryQuery(node) => { rw_data.client_rect_response = process_node_geometry_request(node); }, &QueryMsg::NodeScrollGeometryQuery(node) => { rw_data.scroll_area_response = process_node_scroll_area_request(node); }, &QueryMsg::NodeScrollIdQuery(node) => { let node = unsafe { ServoLayoutNode::new(&node) }; rw_data.scroll_id_response = Some(process_node_scroll_id_request(self.id, node)); }, &QueryMsg::ResolvedStyleQuery(node, ref pseudo, ref property) => { let node = unsafe { ServoLayoutNode::new(&node) }; rw_data.resolved_style_response = process_resolved_style_request(context, node, pseudo, property); }, &QueryMsg::OffsetParentQuery(node) => { rw_data.offset_parent_response = process_offset_parent_query(node); }, &QueryMsg::StyleQuery(node) => { let node = unsafe { ServoLayoutNode::new(&node) }; rw_data.style_response = process_style_query(node); }, &QueryMsg::NodesFromPointQuery(client_point, ref reflow_goal) => { let mut flags = match reflow_goal { &NodesFromPointQueryType::Topmost => webrender_api::HitTestFlags::empty(), &NodesFromPointQueryType::All => webrender_api::HitTestFlags::FIND_ALL, }; // The point we get is not relative to the entire WebRender scene, but to this // particular pipeline, so we need to tell WebRender about that. flags.insert(webrender_api::HitTestFlags::POINT_RELATIVE_TO_PIPELINE_VIEWPORT); let client_point = webrender_api::units::WorldPoint::from_untyped(client_point); let results = self.webrender_api.hit_test( self.webrender_document, Some(self.id.to_webrender()), client_point, flags, ); rw_data.nodes_from_point_response = results .items .iter() .map(|item| UntrustedNodeAddress(item.tag.0 as *const c_void)) .collect() }, &QueryMsg::ElementInnerTextQuery(node) => { let node = unsafe { ServoLayoutNode::new(&node) }; rw_data.element_inner_text_response = process_element_inner_text_query(node); }, }, ReflowGoal::Full | ReflowGoal::TickAnimations => {}, } } fn set_scroll_states<'a, 'b>( &mut self, new_scroll_states: Vec, possibly_locked_rw_data: &mut RwData<'a, 'b>, ) { let mut rw_data = possibly_locked_rw_data.lock(); let mut script_scroll_states = vec![]; let mut layout_scroll_states = HashMap::new(); for new_state in &new_scroll_states { let offset = new_state.scroll_offset; layout_scroll_states.insert(new_state.scroll_id, offset); if new_state.scroll_id.is_root() { script_scroll_states.push((UntrustedNodeAddress::from_id(0), offset)) } else if let Some(node_id) = node_id_from_scroll_id(new_state.scroll_id.0 as usize) { script_scroll_states.push((UntrustedNodeAddress::from_id(node_id), offset)) } } let _ = self .script_chan .send(ConstellationControlMsg::SetScrollState( self.id, script_scroll_states, )); rw_data.scroll_offsets = layout_scroll_states } fn tick_all_animations<'a, 'b>(&mut self) { self.tick_animations(); } fn tick_animations(&mut self) { if self.relayout_event { println!( "**** pipeline={}\tForDisplay\tSpecial\tAnimationTick", self.id ); } if let Some(root) = &*self.fragment_tree_root.borrow() { // Unwrap here should not panic since self.fragment_tree_root is only ever set to Some(_) // in handle_reflow() where self.document_shared_lock is as well. let author_shared_lock = self.document_shared_lock.clone().unwrap(); let author_guard = author_shared_lock.read(); let ua_or_user_guard = UA_STYLESHEETS.shared_lock.read(); let _guards = StylesheetGuards { author: &author_guard, ua_or_user: &ua_or_user_guard, }; self.perform_post_style_recalc_layout_passes(root, &ReflowGoal::TickAnimations, None); } } fn perform_post_style_recalc_layout_passes( &self, fragment_tree: &layout::FragmentTreeRoot, reflow_goal: &ReflowGoal, document: Option<&ServoLayoutDocument>, ) { if !reflow_goal.needs_display() { // Defer the paint step until the next ForDisplay. // // We need to tell the document about this so it doesn't // incorrectly suppress reflows. See #13131. document .expect("No document in a non-display reflow?") .needs_paint_from_layout(); return; } if let Some(document) = document { document.will_paint(); } let viewport_size = webrender_api::units::LayoutSize::from_untyped(Size2D::new( self.viewport_size.width.to_f32_px(), self.viewport_size.height.to_f32_px(), )); let mut display_list = DisplayListBuilder::new(self.id.to_webrender(), viewport_size); let is_contentful = fragment_tree.build_display_list(&mut display_list, self.id, viewport_size); debug!("Layout done!"); let mut epoch = self.epoch.get(); epoch.next(); self.epoch.set(epoch); // Observe notifications about rendered frames if needed right before // sending the display list to WebRender in order to set time related // Progressive Web Metrics. self.paint_time_metrics .maybe_observe_paint_time(self, epoch, is_contentful.0); let mut txn = webrender_api::Transaction::new(); txn.set_display_list( webrender_api::Epoch(epoch.0), None, viewport_size, display_list.wr.finalize(), true, ); txn.generate_frame(); self.webrender_api .send_transaction(self.webrender_document, txn); self.generation.set(self.generation.get() + 1); } /// Returns profiling information which is passed to the time profiler. fn profiler_metadata(&self) -> Option { Some(TimerMetadata { url: self.url.to_string(), iframe: if self.is_iframe { TimerMetadataFrameType::IFrame } else { TimerMetadataFrameType::RootWindow }, incremental: if self.first_reflow.get() { TimerMetadataReflowType::FirstReflow } else { TimerMetadataReflowType::Incremental }, }) } } impl ProfilerMetadataFactory for LayoutThread { fn new_metadata(&self) -> Option { self.profiler_metadata() } } fn get_ua_stylesheets() -> Result { fn parse_ua_stylesheet( shared_lock: &SharedRwLock, filename: &str, content: &[u8], ) -> Result { Ok(DocumentStyleSheet(ServoArc::new(Stylesheet::from_bytes( content, ServoUrl::parse(&format!("chrome://resources/{:?}", filename)).unwrap(), None, None, Origin::UserAgent, MediaList::empty(), shared_lock.clone(), None, None, QuirksMode::NoQuirks, )))) } let shared_lock = &GLOBAL_STYLE_DATA.shared_lock; // FIXME: presentational-hints.css should be at author origin with zero specificity. // (Does it make a difference?) let mut user_or_user_agent_stylesheets = vec![ parse_ua_stylesheet( &shared_lock, "user-agent.css", &resources::read_bytes(Resource::UserAgentCSS), )?, parse_ua_stylesheet( &shared_lock, "servo.css", &resources::read_bytes(Resource::ServoCSS), )?, parse_ua_stylesheet( &shared_lock, "presentational-hints.css", &resources::read_bytes(Resource::PresentationalHintsCSS), )?, ]; for &(ref contents, ref url) in &opts::get().user_stylesheets { user_or_user_agent_stylesheets.push(DocumentStyleSheet(ServoArc::new( Stylesheet::from_bytes( &contents, url.clone(), None, None, Origin::User, MediaList::empty(), shared_lock.clone(), None, Some(&RustLogReporter), QuirksMode::NoQuirks, ), ))); } let quirks_mode_stylesheet = parse_ua_stylesheet( &shared_lock, "quirks-mode.css", &resources::read_bytes(Resource::QuirksModeCSS), )?; Ok(UserAgentStylesheets { shared_lock: shared_lock.clone(), user_or_user_agent_stylesheets: user_or_user_agent_stylesheets, quirks_mode_stylesheet: quirks_mode_stylesheet, }) } lazy_static! { static ref UA_STYLESHEETS: UserAgentStylesheets = { match get_ua_stylesheets() { Ok(stylesheets) => stylesheets, Err(filename) => { error!("Failed to load UA stylesheet {}!", filename); process::exit(1); }, } }; } struct RegisteredPainterImpl { painter: Box, name: Atom, // FIXME: Should be a PrecomputedHashMap. properties: FxHashMap, } impl SpeculativePainter for RegisteredPainterImpl { fn speculatively_draw_a_paint_image( &self, properties: Vec<(Atom, String)>, arguments: Vec, ) { self.painter .speculatively_draw_a_paint_image(properties, arguments); } } impl RegisteredSpeculativePainter for RegisteredPainterImpl { fn properties(&self) -> &FxHashMap { &self.properties } fn name(&self) -> Atom { self.name.clone() } } impl Painter for RegisteredPainterImpl { fn draw_a_paint_image( &self, size: Size2D, device_pixel_ratio: Scale, properties: Vec<(Atom, String)>, arguments: Vec, ) -> Result { self.painter .draw_a_paint_image(size, device_pixel_ratio, properties, arguments) } } struct RegisteredPaintersImpl(FnvHashMap); impl RegisteredSpeculativePainters for RegisteredPaintersImpl { fn get(&self, name: &Atom) -> Option<&dyn RegisteredSpeculativePainter> { self.0 .get(&name) .map(|painter| painter as &dyn RegisteredSpeculativePainter) } }