/* 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/. */
//! 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 layout;
#[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::{Point2D, Rect, Size2D, TypedScale, TypedSize2D};
use fnv::FnvHashMap;
use fxhash::{FxHashMap, FxHashSet};
use gfx::font;
use gfx::font_cache_thread::FontCacheThread;
use gfx::font_context;
use gfx_traits::{node_id_from_scroll_id, Epoch};
use histogram::Histogram;
use ipc_channel::ipc::{self, IpcReceiver, IpcSender};
use ipc_channel::router::ROUTER;
use layout::animation;
use layout::construct::ConstructionResult;
use layout::context::malloc_size_of_persistent_local_context;
use layout::context::LayoutContext;
use layout::context::RegisteredPainter;
use layout::context::RegisteredPainters;
use layout::display_list::items::{OpaqueNode, WebRenderImageInfo};
use layout::display_list::{IndexableText, ToLayout, WebRenderDisplayListConverter};
use layout::flow::{Flow, GetBaseFlow, ImmutableFlowUtils, MutableOwnedFlowUtils};
use layout::flow_ref::FlowRef;
use layout::incremental::{RelayoutMode, SpecialRestyleDamage};
use layout::layout_debug;
use layout::parallel;
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,
};
use layout::sequential;
use layout::traversal::{
ComputeStackingRelativePositions, PreorderFlowTraversal, RecalcStyleAndConstructFlows,
};
use layout::wrapper::LayoutNodeLayoutData;
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::{BrowsingContextId, MonitoredComponentId, TopLevelBrowsingContextId};
use msg::constellation_msg::{LayoutHangAnnotation, MonitoredComponentType, PipelineId};
use net_traits::image_cache::{ImageCache, UsePlaceholder};
use parking_lot::RwLock;
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, Reflow};
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_layout_interface::wrapper_traits::LayoutNode;
use script_traits::Painter;
use script_traits::{ConstellationControlMsg, LayoutControlMsg, LayoutMsg as ConstellationMsg};
use script_traits::{DrawAPaintImageResult, IFrameSizeMsg, PaintWorkletError, WindowSizeType};
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::MaxRect;
use servo_url::ServoUrl;
use std::borrow::ToOwned;
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::{ShowSubtree, ShowSubtreeDataAndPrimaryValues, TDocument, TElement, TNode};
use style::driver;
use style::error_reporting::RustLogReporter;
use style::global_style_data::{GLOBAL_STYLE_DATA, STYLE_THREAD_POOL};
use style::invalidation::element::restyle_hints::RestyleHint;
use style::logical_geometry::LogicalPoint;
use style::media_queries::{Device, MediaList, MediaType};
use style::properties::PropertyId;
use style::selector_parser::SnapshotMap;
use style::servo::restyle_damage::ServoRestyleDamage;
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<Msg>,
/// The port on which we receive messages from the constellation.
pipeline_port: Receiver<LayoutControlMsg>,
/// 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<BackgroundHangMonitor>,
/// The channel on which messages can be sent to the constellation.
constellation_chan: IpcSender<ConstellationMsg>,
/// The channel on which messages can be sent to the script thread.
script_chan: IpcSender<ConstellationControlMsg>,
/// 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,
/// Reference to the script thread image cache.
image_cache: Arc<dyn ImageCache>,
/// Public interface to the font cache thread.
font_cache_thread: FontCacheThread,
/// Is this the first reflow in this LayoutThread?
first_reflow: Cell<bool>,
/// Flag to indicate whether to use parallel operations
parallel_flag: bool,
/// 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<u32>,
/// A channel on which new animations that have been triggered by style recalculation can be
/// sent.
new_animations_sender: Sender<Animation>,
/// Receives newly-discovered animations.
new_animations_receiver: Receiver<Animation>,
/// The number of Web fonts that have been requested but not yet loaded.
outstanding_web_fonts: Arc<AtomicUsize>,
/// The root of the flow tree.
root_flow: RefCell<Option<FlowRef>>,
/// The document-specific shared lock used for author-origin stylesheets
document_shared_lock: Option<SharedRwLock>,
/// The list of currently-running animations.
running_animations: ServoArc<RwLock<FxHashMap<OpaqueNode, Vec<Animation>>>>,
/// The list of animations that have expired since the last style recalculation.
expired_animations: ServoArc<RwLock<FxHashMap<OpaqueNode, Vec<Animation>>>>,
/// A counter for epoch messages
epoch: Cell<Epoch>,
/// The size of the viewport. This may be different from the size of the screen due to viewport
/// constraints.
viewport_size: Size2D<Au>,
/// 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<Mutex<LayoutThreadData>>,
webrender_image_cache: Arc<RwLock<FnvHashMap<(ServoUrl, UsePlaceholder), WebRenderImageInfo>>>,
/// 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,
/// The time a layout query has waited before serviced by layout thread.
layout_query_waiting_time: Histogram,
/// The sizes of all iframes encountered during the last layout operation.
last_iframe_sizes: RefCell<HashMap<BrowsingContextId, TypedSize2D<f32, CSSPixel>>>,
/// Flag that indicates if LayoutThread is busy handling a request.
busy: Arc<AtomicBool>,
}
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<Msg>, Receiver<Msg>),
pipeline_port: IpcReceiver<LayoutControlMsg>,
background_hang_monitor_register: Box<BackgroundHangMonitorRegister>,
constellation_chan: IpcSender<ConstellationMsg>,
script_chan: IpcSender<ConstellationControlMsg>,
image_cache: Arc<dyn ImageCache>,
font_cache_thread: FontCacheThread,
time_profiler_chan: profile_time::ProfilerChan,
mem_profiler_chan: profile_mem::ProfilerChan,
content_process_shutdown_chan: Option<IpcSender<()>>,
webrender_api_sender: webrender_api::RenderApiSender,
webrender_document: webrender_api::DocumentId,
paint_time_metrics: PaintTimeMetrics,
busy: Arc<AtomicBool>,
) {
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,
image_cache.clone(),
font_cache_thread,
time_profiler_chan,
mem_profiler_chan.clone(),
webrender_api_sender,
webrender_document,
paint_time_metrics,
busy,
);
let reporter_name = format!("layout-reporter-{}", id);
mem_profiler_chan.run_with_memory_reporting(
|| {
layout.start();
},
reporter_name,
sender,
Msg::CollectReports,
);
}
if let Some(content_process_shutdown_chan) = content_process_shutdown_chan {
let _ = content_process_shutdown_chan.send(());
}
})
.expect("Thread spawning failed");
}
}
struct ScriptReflowResult {
script_reflow: ScriptReflow,
result: RefCell<Option<ReflowComplete>>,
}
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<Mutex<LayoutThreadData>>,
possibly_locked_rw_data: &'a mut Option<MutexGuard<'b, LayoutThreadData>>,
}
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<AtomicUsize>,
) {
if opts::get().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<Msg>,
pipeline_port: IpcReceiver<LayoutControlMsg>,
background_hang_monitor: Box<BackgroundHangMonitor>,
constellation_chan: IpcSender<ConstellationMsg>,
script_chan: IpcSender<ConstellationControlMsg>,
image_cache: Arc<dyn ImageCache>,
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<AtomicBool>,
) -> 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(),
opts::get().initial_window_size.to_f32() * TypedScale::new(1.0),
TypedScale::new(opts::get().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,
constellation_chan: constellation_chan.clone(),
time_profiler_chan: time_profiler_chan,
mem_profiler_chan: mem_profiler_chan,
registered_painters: RegisteredPaintersImpl(Default::default()),
image_cache: image_cache.clone(),
font_cache_thread: font_cache_thread,
first_reflow: Cell::new(true),
font_cache_receiver: font_cache_receiver,
font_cache_sender: ipc_font_cache_sender,
parallel_flag: true,
generation: Cell::new(0),
new_animations_sender: new_animations_sender,
new_animations_receiver: new_animations_receiver,
outstanding_web_fonts: Arc::new(AtomicUsize::new(0)),
root_flow: RefCell::new(None),
document_shared_lock: None,
running_animations: ServoArc::new(RwLock::new(Default::default())),
expired_animations: ServoArc::new(RwLock::new(Default::default())),
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,
indexable_text: IndexableText::default(),
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(),
})),
webrender_image_cache: Arc::new(RwLock::new(FnvHashMap::default())),
timer: if pref!(layout.animations.test.enabled) {
Timer::test_mode()
} else {
Timer::new()
},
paint_time_metrics: paint_time_metrics,
layout_query_waiting_time: Histogram::new(),
last_iframe_sizes: Default::default(),
busy: busy,
}
}
/// 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>,
script_initiated_layout: bool,
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: self.running_animations.clone(),
expired_animations: self.expired_animations.clone(),
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,
},
image_cache: self.image_cache.clone(),
font_cache_thread: Mutex::new(self.font_cache_thread.clone()),
webrender_image_cache: self.webrender_image_cache.clone(),
pending_images: if script_initiated_layout {
Some(Mutex::new(vec![]))
} else {
None
},
newly_transitioning_nodes: if script_initiated_layout {
Some(Mutex::new(vec![]))
} else {
None
},
registered_painters: &self.registered_painters,
}
}
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<dyn LayoutRPC + Send>)
.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(possibly_locked_rw_data),
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::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, possibly_locked_rw_data, 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, mut properties, painter) => {
debug!("Registering the painter");
let properties = properties
.drain(..)
.filter_map(|name| {
let id = PropertyId::parse_enabled_for_all_content(&*name).ok()?;
Some((name.clone(), id))
})
.filter(|&(_, ref id)| !id.is_shorthand())
.collect();
let registered_painter = RegisteredPainterImpl {
name: name.clone(),
properties,
painter,
};
self.registered_painters.0.insert(name, registered_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(self.running_animations.read().len());
},
}
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),
});
// The LayoutThread has data in Persistent TLS...
reports.push(Report {
path: path![formatted_url, "layout-thread", "local-context"],
kind: ReportKind::ExplicitJemallocHeapSize,
size: malloc_size_of_persistent_local_context(&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(),
info.content_process_shutdown_chan,
self.webrender_api.clone_sender(),
self.webrender_document,
info.paint_time_metrics,
info.layout_is_busy,
);
}
/// 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`"),
}
}
}
/// Shuts down the layout thread now. If there are any DOM nodes left, layout will now (safely)
/// crash.
fn exit_now(&mut self) {
// Drop the root flow explicitly to avoid holding style data, such as
// rule nodes. The `Stylist` checks when it is dropped that all rule
// nodes have been GCed, so we want drop anyone who holds them first.
let waiting_time_min = self.layout_query_waiting_time.minimum().unwrap_or(0);
let waiting_time_max = self.layout_query_waiting_time.maximum().unwrap_or(0);
let waiting_time_mean = self.layout_query_waiting_time.mean().unwrap_or(0);
let waiting_time_stddev = self.layout_query_waiting_time.stddev().unwrap_or(0);
debug!(
"layout: query waiting time: min: {}, max: {}, mean: {}, standard_deviation: {}",
waiting_time_min, waiting_time_max, waiting_time_mean, waiting_time_stddev
);
self.root_flow.borrow_mut().take();
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,
);
}
}
/// Advances the animation clock of the document.
fn handle_advance_clock_ms<'a, 'b>(
&mut self,
how_many_ms: i32,
possibly_locked_rw_data: &mut RwData<'a, 'b>,
tick_animations: bool,
) {
self.timer.increment(how_many_ms as f64 / 1000.0);
if tick_animations {
self.tick_all_animations(possibly_locked_rw_data);
}
}
/// 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);
}
fn try_get_layout_root<N: LayoutNode>(&self, node: N) -> Option<FlowRef> {
let result = node.mutate_layout_data()?.flow_construction_result.get();
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,
};
FlowRef::deref_mut(&mut flow).mark_as_root();
Some(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(layout_root: &mut dyn Flow, layout_context: &LayoutContext) {
let _scope = layout_debug_scope!("solve_constraints");
sequential::reflow(layout_root, layout_context, RelayoutMode::Incremental);
}
/// 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(
traversal: &rayon::ThreadPool,
layout_root: &mut dyn Flow,
profiler_metadata: Option<TimerMetadata>,
time_profiler_chan: profile_time::ProfilerChan,
layout_context: &LayoutContext,
) {
let _scope = layout_debug_scope!("solve_constraints_parallel");
// NOTE: this currently computes borders, so any pruning should separate that
// operation out.
parallel::reflow(
layout_root,
profiler_metadata,
time_profiler_chan,
layout_context,
traversal,
);
}
/// Computes the stacking-relative positions of all flows and, if the painting is dirty and the
/// reflow type need it, builds the display list.
fn compute_abs_pos_and_build_display_list(
&self,
data: &Reflow,
reflow_goal: &ReflowGoal,
document: Option<&ServoLayoutDocument>,
layout_root: &mut dyn Flow,
layout_context: &mut LayoutContext,
rw_data: &mut LayoutThreadData,
) {
let writing_mode = layout_root.base().writing_mode;
let (metadata, sender) = (self.profiler_metadata(), self.time_profiler_chan.clone());
profile(
profile_time::ProfilerCategory::LayoutDispListBuild,
metadata.clone(),
sender.clone(),
|| {
layout_root.mut_base().stacking_relative_position =
LogicalPoint::zero(writing_mode)
.to_physical(writing_mode, self.viewport_size)
.to_vector();
layout_root.mut_base().clip = data.page_clip_rect;
let traversal = ComputeStackingRelativePositions {
layout_context: layout_context,
};
traversal.traverse(layout_root);
if layout_root
.base()
.restyle_damage
.contains(ServoRestyleDamage::REPAINT) ||
rw_data.display_list.is_none()
{
if reflow_goal.needs_display_list() {
let mut build_state =
sequential::build_display_list_for_subtree(layout_root, layout_context);
debug!("Done building display list.");
let root_size = {
let root_flow = layout_root.base();
if self.stylist.viewport_constraints().is_some() {
root_flow.position.size.to_physical(root_flow.writing_mode)
} else {
root_flow.overflow.scroll.size
}
};
let origin = Rect::new(Point2D::new(Au(0), Au(0)), root_size).to_layout();
build_state.root_stacking_context.bounds = origin;
build_state.root_stacking_context.overflow = origin;
if !build_state.iframe_sizes.is_empty() {
// build_state.iframe_sizes is only used here, so its okay to replace
// it with an empty vector
let iframe_sizes =
std::mem::replace(&mut build_state.iframe_sizes, vec![]);
// Collect the last frame's iframe sizes to compute any differences.
// Every frame starts with a fresh collection so that any removed
// iframes do not linger.
let last_iframe_sizes = std::mem::replace(
&mut *self.last_iframe_sizes.borrow_mut(),
HashMap::default(),
);
let mut size_messages = vec![];
for new_size in iframe_sizes {
// Only notify the constellation about existing iframes
// that have a new size, or iframes that did not previously
// exist.
if let Some(old_size) = last_iframe_sizes.get(&new_size.id) {
if *old_size != new_size.size {
size_messages.push(IFrameSizeMsg {
data: new_size,
type_: WindowSizeType::Resize,
});
}
} else {
size_messages.push(IFrameSizeMsg {
data: new_size,
type_: WindowSizeType::Initial,
});
}
self.last_iframe_sizes
.borrow_mut()
.insert(new_size.id, new_size.size);
}
if !size_messages.is_empty() {
let msg = ConstellationMsg::IFrameSizes(size_messages);
if let Err(e) = self.constellation_chan.send(msg) {
warn!("Layout resize to constellation failed ({}).", e);
}
}
}
rw_data.indexable_text = std::mem::replace(
&mut build_state.indexable_text,
IndexableText::default(),
);
rw_data.display_list = Some(Arc::new(build_state.to_display_list()));
}
}
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 display_list = (*rw_data.display_list.as_ref().unwrap()).clone();
if opts::get().dump_display_list {
display_list.print();
}
if opts::get().dump_display_list_json {
println!("{}", serde_json::to_string_pretty(&display_list).unwrap());
}
debug!("Layout done!");
// TODO: Avoid the temporary conversion and build webrender sc/dl directly!
let builder = rw_data
.display_list
.as_ref()
.unwrap()
.convert_to_webrender(self.id);
let viewport_size = Size2D::new(
self.viewport_size.width.to_f32_px(),
self.viewport_size.height.to_f32_px(),
);
let mut epoch = self.epoch.get();
epoch.next();
self.epoch.set(epoch);
let viewport_size = webrender_api::LayoutSize::from_untyped(&viewport_size);
// 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, &*display_list);
let mut txn = webrender_api::Transaction::new();
txn.set_display_list(
webrender_api::Epoch(epoch.0),
Some(get_root_flow_background_color(layout_root)),
viewport_size,
builder.finalize(),
true,
);
txn.generate_frame();
self.webrender_api
.send_transaction(self.webrender_document, txn);
},
);
}
/// 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();
// Parallelize if there's more than 750 objects based on rzambre's suggestion
// https://github.com/servo/servo/issues/10110
self.parallel_flag = data.dom_count > 750;
debug!("layout: received layout request for: {}", self.url);
debug!("Number of objects in DOM: {}", data.dom_count);
debug!("layout: parallel? {}", self.parallel_flag);
let mut rw_data = possibly_locked_rw_data.lock();
// Record the time that layout query has been waited.
let now = time::precise_time_ns();
if let ReflowGoal::LayoutQuery(_, timestamp) = data.reflow_goal {
self.layout_query_waiting_time
.increment(now - timestamp)
.expect("layout: wrong layout query timestamp");
};
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,
};
debug!(
"layout: processing reflow request for: {:?} ({}) (query={:?})",
element, self.url, data.reflow_goal
);
trace!("{:?}", ShowSubtree(element.as_node()));
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| {
debug!("Viewport constraints: {:?}", constraints);
// other rules are evaluated against the actual viewport
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() {
debug!("First reflow, rebuilding user and UA rules");
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 {
debug!("Doc sheets changed, flushing author sheets too");
self.stylist
.force_stylesheet_origins_dirty(Origin::Author.into());
}
}
if viewport_size_changed {
if let Some(mut flow) = self.try_get_layout_root(element.as_node()) {
LayoutThread::reflow_all_nodes(FlowRef::deref_mut(&mut flow));
}
}
debug!(
"Shadow roots in document {:?}",
document.shadow_roots().len()
);
// 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();
debug!("Draining restyles: {}", restyles.len());
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(), true, &map);
let (thread_pool, num_threads) = if self.parallel_flag {
(
STYLE_THREAD_POOL.style_thread_pool.as_ref(),
STYLE_THREAD_POOL.num_threads,
)
} else {
(None, 1)
};
let traversal = RecalcStyleAndConstructFlows::new(layout_context);
let token = {
let shared =
<RecalcStyleAndConstructFlows as DomTraversal<ServoLayoutElement>>::shared_context(
&traversal,
);
RecalcStyleAndConstructFlows::pre_traverse(element, shared)
};
if token.should_traverse() {
// Recalculate CSS styles and rebuild flows and fragments.
profile(
profile_time::ProfilerCategory::LayoutStyleRecalc,
self.profiler_metadata(),
self.time_profiler_chan.clone(),
|| {
// Perform CSS selector matching and flow construction.
driver::traverse_dom::<ServoLayoutElement, RecalcStyleAndConstructFlows>(
&traversal,
token,
thread_pool,
);
},
);
// TODO(pcwalton): Measure energy usage of text shaping, perhaps?
let text_shaping_time =
font::get_and_reset_text_shaping_performance_counter() / num_threads;
profile_time::send_profile_data(
profile_time::ProfilerCategory::LayoutTextShaping,
self.profiler_metadata(),
&self.time_profiler_chan,
0,
text_shaping_time as u64,
0,
0,
);
// Retrieve the (possibly rebuilt) root flow.
*self.root_flow.borrow_mut() = self.try_get_layout_root(element.as_node());
}
for element in elements_with_snapshot {
unsafe { element.unset_snapshot_flags() }
}
layout_context = traversal.destroy();
if opts::get().dump_style_tree {
println!("{:?}", ShowSubtreeDataAndPrimaryValues(element.as_node()));
}
if opts::get().dump_rule_tree {
layout_context
.style_context
.stylist
.rule_tree()
.dump_stdout(&guards);
}
// 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(mut root_flow) = self.root_flow.borrow().clone() {
self.perform_post_style_recalc_layout_passes(
&mut root_flow,
&data.reflow_info,
&data.reflow_goal,
Some(&document),
&mut rw_data,
&mut layout_context,
FxHashSet::default(),
);
}
self.first_reflow.set(false);
self.respond_to_query_if_necessary(
&data.reflow_goal,
&mut *rw_data,
&mut layout_context,
data.result.borrow_mut().as_mut().unwrap(),
);
}
fn respond_to_query_if_necessary(
&self,
reflow_goal: &ReflowGoal,
rw_data: &mut LayoutThreadData,
context: &mut LayoutContext,
reflow_result: &mut ReflowComplete,
) {
let pending_images = match context.pending_images {
Some(ref pending) => std::mem::replace(&mut *pending.lock().unwrap(), vec![]),
None => vec![],
};
reflow_result.pending_images = pending_images;
let newly_transitioning_nodes = match context.newly_transitioning_nodes {
Some(ref nodes) => std::mem::replace(&mut *nodes.lock().unwrap(), vec![]),
None => vec![],
};
reflow_result.newly_transitioning_nodes = newly_transitioning_nodes;
let mut root_flow = match self.root_flow.borrow().clone() {
Some(root_flow) => root_flow,
None => return,
};
let root_flow = FlowRef::deref_mut(&mut root_flow);
match *reflow_goal {
ReflowGoal::LayoutQuery(ref querymsg, _) => match querymsg {
&QueryMsg::ContentBoxQuery(node) => {
rw_data.content_box_response = process_content_box_request(node, root_flow);
},
&QueryMsg::ContentBoxesQuery(node) => {
rw_data.content_boxes_response = process_content_boxes_request(node, root_flow);
},
&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 =
TextIndexResponse(rw_data.indexable_text.text_index(node, point_in_node));
},
&QueryMsg::NodeGeometryQuery(node) => {
rw_data.client_rect_response = process_node_geometry_request(node, root_flow);
},
&QueryMsg::NodeScrollGeometryQuery(node) => {
rw_data.scroll_area_response =
process_node_scroll_area_request(node, root_flow);
},
&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, root_flow);
},
&QueryMsg::OffsetParentQuery(node) => {
rw_data.offset_parent_response = process_offset_parent_query(node, root_flow);
},
&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::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, &rw_data.indexable_text);
},
},
ReflowGoal::Full | ReflowGoal::TickAnimations => {},
}
}
fn set_scroll_states<'a, 'b>(
&mut self,
new_scroll_states: Vec<ScrollState>,
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, possibly_locked_rw_data: &mut RwData<'a, 'b>) {
let mut rw_data = possibly_locked_rw_data.lock();
self.tick_animations(&mut rw_data);
}
fn tick_animations(&mut self, rw_data: &mut LayoutThreadData) {
if opts::get().relayout_event {
println!(
"**** pipeline={}\tForDisplay\tSpecial\tAnimationTick",
self.id
);
}
if let Some(mut root_flow) = self.root_flow.borrow().clone() {
let reflow_info = Reflow {
page_clip_rect: Rect::max_rect(),
};
// Unwrap here should not panic since self.root_flow 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,
};
let snapshots = SnapshotMap::new();
let mut layout_context = self.build_layout_context(guards, false, &snapshots);
let invalid_nodes = {
// Perform an abbreviated style recalc that operates without access to the DOM.
let animations = self.running_animations.read();
profile(
profile_time::ProfilerCategory::LayoutStyleRecalc,
self.profiler_metadata(),
self.time_profiler_chan.clone(),
|| {
animation::recalc_style_for_animations::<ServoLayoutElement>(
&layout_context,
FlowRef::deref_mut(&mut root_flow),
&animations,
)
},
)
};
self.perform_post_style_recalc_layout_passes(
&mut root_flow,
&reflow_info,
&ReflowGoal::TickAnimations,
None,
&mut *rw_data,
&mut layout_context,
invalid_nodes,
);
assert!(layout_context.pending_images.is_none());
assert!(layout_context.newly_transitioning_nodes.is_none());
}
}
fn perform_post_style_recalc_layout_passes(
&self,
root_flow: &mut FlowRef,
data: &Reflow,
reflow_goal: &ReflowGoal,
document: Option<&ServoLayoutDocument>,
rw_data: &mut LayoutThreadData,
context: &mut LayoutContext,
invalid_nodes: FxHashSet<OpaqueNode>,
) {
{
let mut newly_transitioning_nodes = context
.newly_transitioning_nodes
.as_ref()
.map(|nodes| nodes.lock().unwrap());
let newly_transitioning_nodes =
newly_transitioning_nodes.as_mut().map(|nodes| &mut **nodes);
// Kick off animations if any were triggered, expire completed ones.
animation::update_animation_state::<ServoLayoutElement>(
&self.constellation_chan,
&self.script_chan,
&mut *self.running_animations.write(),
&mut *self.expired_animations.write(),
invalid_nodes,
newly_transitioning_nodes,
&self.new_animations_receiver,
self.id,
&self.timer,
);
}
profile(
profile_time::ProfilerCategory::LayoutRestyleDamagePropagation,
self.profiler_metadata(),
self.time_profiler_chan.clone(),
|| {
// Call `compute_layout_damage` even in non-incremental mode, because it sets flags
// that are needed in both incremental and non-incremental traversals.
let damage = FlowRef::deref_mut(root_flow).compute_layout_damage();
if opts::get().nonincremental_layout ||
damage.contains(SpecialRestyleDamage::REFLOW_ENTIRE_DOCUMENT)
{
FlowRef::deref_mut(root_flow).reflow_entire_document()
}
},
);
if opts::get().trace_layout {
layout_debug::begin_trace(root_flow.clone());
}
// Resolve generated content.
profile(
profile_time::ProfilerCategory::LayoutGeneratedContent,
self.profiler_metadata(),
self.time_profiler_chan.clone(),
|| sequential::resolve_generated_content(FlowRef::deref_mut(root_flow), &context),
);
// Guess float placement.
profile(
profile_time::ProfilerCategory::LayoutFloatPlacementSpeculation,
self.profiler_metadata(),
self.time_profiler_chan.clone(),
|| sequential::guess_float_placement(FlowRef::deref_mut(root_flow)),
);
// Perform the primary layout passes over the flow tree to compute the locations of all
// the boxes.
if root_flow
.base()
.restyle_damage
.intersects(ServoRestyleDamage::REFLOW | ServoRestyleDamage::REFLOW_OUT_OF_FLOW)
{
profile(
profile_time::ProfilerCategory::LayoutMain,
self.profiler_metadata(),
self.time_profiler_chan.clone(),
|| {
let profiler_metadata = self.profiler_metadata();
let thread_pool = if self.parallel_flag {
STYLE_THREAD_POOL.style_thread_pool.as_ref()
} else {
None
};
if let Some(pool) = thread_pool {
// Parallel mode.
LayoutThread::solve_constraints_parallel(
pool,
FlowRef::deref_mut(root_flow),
profiler_metadata,
self.time_profiler_chan.clone(),
&*context,
);
} else {
//Sequential mode
LayoutThread::solve_constraints(FlowRef::deref_mut(root_flow), &context)
}
},
);
}
profile(
profile_time::ProfilerCategory::LayoutStoreOverflow,
self.profiler_metadata(),
self.time_profiler_chan.clone(),
|| {
sequential::store_overflow(context, FlowRef::deref_mut(root_flow) as &mut dyn Flow);
},
);
self.perform_post_main_layout_passes(
data,
root_flow,
reflow_goal,
document,
rw_data,
context,
);
}
fn perform_post_main_layout_passes(
&self,
data: &Reflow,
mut root_flow: &mut FlowRef,
reflow_goal: &ReflowGoal,
document: Option<&ServoLayoutDocument>,
rw_data: &mut LayoutThreadData,
layout_context: &mut LayoutContext,
) {
// Build the display list if necessary, and send it to the painter.
self.compute_abs_pos_and_build_display_list(
data,
reflow_goal,
document,
FlowRef::deref_mut(&mut root_flow),
&mut *layout_context,
rw_data,
);
if opts::get().trace_layout {
layout_debug::end_trace(self.generation.get());
}
if opts::get().dump_flow_tree {
root_flow.print("Post layout flow tree".to_owned());
}
self.generation.set(self.generation.get() + 1);
}
fn reflow_all_nodes(flow: &mut dyn Flow) {
debug!("reflowing all nodes!");
flow.mut_base().restyle_damage.insert(
ServoRestyleDamage::REPAINT |
ServoRestyleDamage::STORE_OVERFLOW |
ServoRestyleDamage::REFLOW |
ServoRestyleDamage::REPOSITION,
);
for child in flow.mut_base().child_iter_mut() {
LayoutThread::reflow_all_nodes(child);
}
}
/// Returns profiling information which is passed to the time profiler.
fn profiler_metadata(&self) -> Option<TimerMetadata> {
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<TimerMetadata> {
self.profiler_metadata()
}
}
// 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 dyn Flow) -> webrender_api::ColorF {
let transparent = webrender_api::ColorF {
r: 0.0,
g: 0.0,
b: 0.0,
a: 0.0,
};
if !flow.is_block_like() {
return transparent;
}
let block_flow = flow.as_mut_block();
let kid = match block_flow.base.children.iter_mut().next() {
None => return transparent,
Some(kid) => kid,
};
if !kid.is_block_like() {
return transparent;
}
let kid_block_flow = kid.as_block();
let color = kid_block_flow.fragment.style.resolve_color(
kid_block_flow
.fragment
.style
.get_background()
.background_color,
);
webrender_api::ColorF::new(
color.red_f32(),
color.green_f32(),
color.blue_f32(),
color.alpha_f32(),
)
}
fn get_ua_stylesheets() -> Result<UserAgentStylesheets, &'static str> {
fn parse_ua_stylesheet(
shared_lock: &SharedRwLock,
filename: &str,
content: &[u8],
) -> Result<DocumentStyleSheet, &'static str> {
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<dyn Painter>,
name: Atom,
// FIXME: Should be a PrecomputedHashMap.
properties: FxHashMap<Atom, PropertyId>,
}
impl SpeculativePainter for RegisteredPainterImpl {
fn speculatively_draw_a_paint_image(
&self,
properties: Vec<(Atom, String)>,
arguments: Vec<String>,
) {
self.painter
.speculatively_draw_a_paint_image(properties, arguments);
}
}
impl RegisteredSpeculativePainter for RegisteredPainterImpl {
fn properties(&self) -> &FxHashMap<Atom, PropertyId> {
&self.properties
}
fn name(&self) -> Atom {
self.name.clone()
}
}
impl Painter for RegisteredPainterImpl {
fn draw_a_paint_image(
&self,
size: TypedSize2D<f32, CSSPixel>,
device_pixel_ratio: TypedScale<f32, CSSPixel, DevicePixel>,
properties: Vec<(Atom, String)>,
arguments: Vec<String>,
) -> Result<DrawAPaintImageResult, PaintWorkletError> {
self.painter
.draw_a_paint_image(size, device_pixel_ratio, properties, arguments)
}
}
impl RegisteredPainter for RegisteredPainterImpl {}
struct RegisteredPaintersImpl(FnvHashMap<Atom, RegisteredPainterImpl>);
impl RegisteredSpeculativePainters for RegisteredPaintersImpl {
fn get(&self, name: &Atom) -> Option<&dyn RegisteredSpeculativePainter> {
self.0
.get(&name)
.map(|painter| painter as &dyn RegisteredSpeculativePainter)
}
}
impl RegisteredPainters for RegisteredPaintersImpl {
fn get(&self, name: &Atom) -> Option<&dyn RegisteredPainter> {
self.0
.get(&name)
.map(|painter| painter as &dyn RegisteredPainter)
}
}