/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
//! The layout thread. Performs layout on the DOM, builds display lists and sends them to be
//! painted.
#![feature(box_syntax)]
#![feature(mpsc_select)]
#![feature(plugin)]
#![feature(proc_macro)]
#![plugin(plugins)]
extern crate app_units;
extern crate core;
extern crate euclid;
extern crate fnv;
extern crate gfx;
extern crate gfx_traits;
extern crate heapsize;
#[macro_use] extern crate heapsize_derive;
extern crate ipc_channel;
#[macro_use]
extern crate layout;
extern crate layout_traits;
#[allow(unused_extern_crates)]
#[macro_use]
extern crate lazy_static;
#[macro_use]
extern crate log;
extern crate msg;
extern crate net_traits;
extern crate parking_lot;
#[macro_use]
extern crate profile_traits;
extern crate rayon;
extern crate script;
extern crate script_layout_interface;
extern crate script_traits;
extern crate selectors;
extern crate serde_json;
extern crate servo_url;
extern crate style;
extern crate util;
extern crate webrender_traits;
use app_units::Au;
use euclid::point::Point2D;
use euclid::rect::Rect;
use euclid::scale_factor::ScaleFactor;
use euclid::size::Size2D;
use fnv::FnvHasher;
use gfx::display_list::{ClippingRegion, OpaqueNode};
use gfx::display_list::WebRenderImageInfo;
use gfx::font;
use gfx::font_cache_thread::FontCacheThread;
use gfx::font_context;
use gfx_traits::{Epoch, FragmentType, ScrollRootId};
use heapsize::HeapSizeOf;
use ipc_channel::ipc::{self, IpcReceiver, IpcSender};
use ipc_channel::router::ROUTER;
use layout::animation;
use layout::construct::ConstructionResult;
use layout::context::{LayoutContext, SharedLayoutContext, heap_size_of_local_context};
use layout::display_list_builder::ToGfxColor;
use layout::flow::{self, Flow, ImmutableFlowUtils, MutableFlowUtils, MutableOwnedFlowUtils};
use layout::flow_ref::FlowRef;
use layout::incremental::{LayoutDamageComputation, REFLOW_ENTIRE_DOCUMENT};
use layout::layout_debug;
use layout::parallel;
use layout::query::{LayoutRPCImpl, LayoutThreadData, process_content_box_request, process_content_boxes_request};
use layout::query::{process_margin_style_query, process_node_overflow_request, process_resolved_style_request};
use layout::query::{process_node_geometry_request, process_node_scroll_area_request};
use layout::query::process_offset_parent_query;
use layout::sequential;
use layout::traversal::{ComputeAbsolutePositions, RecalcStyleAndConstructFlows};
use layout::webrender_helpers::{WebRenderDisplayListConverter, WebRenderFrameBuilder};
use layout::wrapper::LayoutNodeLayoutData;
use layout::wrapper::drop_style_and_layout_data;
use layout_traits::LayoutThreadFactory;
use msg::constellation_msg::{FrameId, PipelineId};
use net_traits::image_cache_thread::{ImageCacheChan, ImageCacheResult, ImageCacheThread};
use net_traits::image_cache_thread::UsePlaceholder;
use parking_lot::RwLock;
use profile_traits::mem::{self, Report, ReportKind, ReportsChan};
use profile_traits::time::{self, TimerMetadata, profile};
use profile_traits::time::{TimerMetadataFrameType, TimerMetadataReflowType};
use script::layout_wrapper::{ServoLayoutElement, ServoLayoutDocument, ServoLayoutNode};
use script_layout_interface::message::{Msg, NewLayoutThreadInfo, Reflow, ReflowQueryType, ScriptReflow};
use script_layout_interface::reporter::CSSErrorReporter;
use script_layout_interface::rpc::{LayoutRPC, MarginStyleResponse, NodeOverflowResponse, OffsetParentResponse};
use script_layout_interface::wrapper_traits::LayoutNode;
use script_traits::{ConstellationControlMsg, LayoutControlMsg, LayoutMsg as ConstellationMsg};
use script_traits::{StackingContextScrollState, UntrustedNodeAddress};
use selectors::Element;
use servo_url::ServoUrl;
use std::borrow::ToOwned;
use std::collections::HashMap;
use std::hash::BuildHasherDefault;
use std::ops::{Deref, DerefMut};
use std::process;
use std::sync::{Arc, Mutex, MutexGuard};
use std::sync::atomic::{AtomicUsize, Ordering};
use std::sync::mpsc::{Receiver, Sender, channel};
use style::animation::Animation;
use style::context::{LocalStyleContextCreationInfo, ReflowGoal, SharedStyleContext};
use style::data::StoredRestyleHint;
use style::dom::{StylingMode, TElement, TNode};
use style::error_reporting::{ParseErrorReporter, StdoutErrorReporter};
use style::logical_geometry::LogicalPoint;
use style::media_queries::{Device, MediaType};
use style::parser::ParserContextExtraData;
use style::servo::restyle_damage::{REFLOW, REFLOW_OUT_OF_FLOW, REPAINT, REPOSITION, STORE_OVERFLOW};
use style::stylesheets::{Origin, Stylesheet, UserAgentStylesheets};
use style::stylist::Stylist;
use style::thread_state;
use style::timer::Timer;
use util::geometry::max_rect;
use util::opts;
use util::prefs::PREFS;
use util::resource_files::read_resource_file;
use util::thread;
/// Information needed by the layout thread.
pub struct LayoutThread {
/// The ID of the pipeline that we belong to.
id: PipelineId,
/// The URL of the pipeline that we belong to.
url: ServoUrl,
/// 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 image cache
image_cache_receiver: Receiver<ImageCacheResult>,
/// The channel on which the image cache can send messages to ourself.
image_cache_sender: ImageCacheChan,
/// 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<()>,
/// 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: time::ProfilerChan,
/// The channel on which messages can be sent to the memory profiler.
mem_profiler_chan: mem::ProfilerChan,
/// The channel on which messages can be sent to the image cache.
image_cache_thread: ImageCacheThread,
/// Public interface to the font cache thread.
font_cache_thread: FontCacheThread,
/// Is this the first reflow in this LayoutThread?
first_reflow: bool,
/// The workers that we use for parallel operation.
parallel_traversal: Option<rayon::ThreadPool>,
/// Starts at zero, and increased by one every time a layout completes.
/// This can be used to easily check for invalid stale data.
generation: 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: Option<FlowRef>,
/// The list of currently-running animations.
running_animations: Arc<RwLock<HashMap<OpaqueNode, Vec<Animation>>>>,
/// The list of animations that have expired since the last style recalculation.
expired_animations: Arc<RwLock<HashMap<OpaqueNode, Vec<Animation>>>>,
/// A counter for epoch messages
epoch: 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>>,
/// The CSS error reporter for all CSS loaded in this layout thread
error_reporter: CSSErrorReporter,
webrender_image_cache: Arc<RwLock<HashMap<(ServoUrl, UsePlaceholder),
WebRenderImageInfo,
BuildHasherDefault<FnvHasher>>>>,
// Webrender interface.
webrender_api: webrender_traits::RenderApi,
/// The timer object to control the timing of the animations. This should
/// only be a test-mode timer during testing for animations.
timer: Timer,
// Number of layout threads. This is copied from `util::opts`, but we'd
// rather limit the dependency on that module here.
layout_threads: usize,
}
impl LayoutThreadFactory for LayoutThread {
type Message = Msg;
/// Spawns a new layout thread.
fn create(id: PipelineId,
top_level_frame_id: Option<FrameId>,
url: ServoUrl,
is_iframe: bool,
chan: (Sender<Msg>, Receiver<Msg>),
pipeline_port: IpcReceiver<LayoutControlMsg>,
constellation_chan: IpcSender<ConstellationMsg>,
script_chan: IpcSender<ConstellationControlMsg>,
image_cache_thread: ImageCacheThread,
font_cache_thread: FontCacheThread,
time_profiler_chan: time::ProfilerChan,
mem_profiler_chan: mem::ProfilerChan,
content_process_shutdown_chan: IpcSender<()>,
webrender_api_sender: webrender_traits::RenderApiSender,
layout_threads: usize) {
thread::spawn_named(format!("LayoutThread {:?}", id),
move || {
thread_state::initialize(thread_state::LAYOUT);
if let Some(top_level_frame_id) = top_level_frame_id {
FrameId::install(top_level_frame_id);
}
{ // Ensures layout thread is destroyed before we send shutdown message
let sender = chan.0;
let layout = LayoutThread::new(id,
url,
is_iframe,
chan.1,
pipeline_port,
constellation_chan,
script_chan,
image_cache_thread,
font_cache_thread,
time_profiler_chan,
mem_profiler_chan.clone(),
webrender_api_sender,
layout_threads);
let reporter_name = format!("layout-reporter-{}", id);
mem_profiler_chan.run_with_memory_reporting(|| {
layout.start();
}, reporter_name, sender, Msg::CollectReports);
}
let _ = content_process_shutdown_chan.send(());
});
}
}
/// 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),
}
}
/// If no reflow has ever been triggered, this will keep the lock, locked
/// (and saved in `possibly_locked_rw_data`). If it has been, the lock will
/// be unlocked.
fn block(&mut self, rw_data: RWGuard<'b>) {
match rw_data {
RWGuard::Used(x) => drop(x),
RWGuard::Held(x) => *self.possibly_locked_rw_data = Some(x),
}
}
}
fn add_font_face_rules(stylesheet: &Stylesheet,
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, |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, |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,
url: ServoUrl,
is_iframe: bool,
port: Receiver<Msg>,
pipeline_port: IpcReceiver<LayoutControlMsg>,
constellation_chan: IpcSender<ConstellationMsg>,
script_chan: IpcSender<ConstellationControlMsg>,
image_cache_thread: ImageCacheThread,
font_cache_thread: FontCacheThread,
time_profiler_chan: time::ProfilerChan,
mem_profiler_chan: mem::ProfilerChan,
webrender_api_sender: webrender_traits::RenderApiSender,
layout_threads: usize)
-> LayoutThread {
let device = Device::new(
MediaType::Screen,
opts::get().initial_window_size.to_f32() * ScaleFactor::new(1.0));
let parallel_traversal = if layout_threads != 1 {
let configuration =
rayon::Configuration::new().set_num_threads(layout_threads);
rayon::ThreadPool::new(configuration).ok()
} else {
None
};
// Create the channel on which new animations can be sent.
let (new_animations_sender, new_animations_receiver) = channel();
// Proxy IPC messages from the pipeline to the layout thread.
let pipeline_receiver = ROUTER.route_ipc_receiver_to_new_mpsc_receiver(pipeline_port);
// Ask the router to proxy IPC messages from the image cache thread to the layout thread.
let (ipc_image_cache_sender, ipc_image_cache_receiver) = ipc::channel().unwrap();
let image_cache_receiver =
ROUTER.route_ipc_receiver_to_new_mpsc_receiver(ipc_image_cache_receiver);
// 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_mpsc_receiver(ipc_font_cache_receiver);
let stylist = Arc::new(Stylist::new(device));
let outstanding_web_fonts_counter = Arc::new(AtomicUsize::new(0));
for stylesheet in &*UA_STYLESHEETS.user_or_user_agent_stylesheets {
add_font_face_rules(stylesheet,
&stylist.device,
&font_cache_thread,
&ipc_font_cache_sender,
&outstanding_web_fonts_counter);
}
LayoutThread {
id: id,
url: url,
is_iframe: is_iframe,
port: port,
pipeline_port: pipeline_receiver,
script_chan: script_chan.clone(),
constellation_chan: constellation_chan.clone(),
time_profiler_chan: time_profiler_chan,
mem_profiler_chan: mem_profiler_chan,
image_cache_thread: image_cache_thread,
font_cache_thread: font_cache_thread,
first_reflow: true,
image_cache_receiver: image_cache_receiver,
image_cache_sender: ImageCacheChan(ipc_image_cache_sender),
font_cache_receiver: font_cache_receiver,
font_cache_sender: ipc_font_cache_sender,
parallel_traversal: parallel_traversal,
generation: 0,
new_animations_sender: new_animations_sender,
new_animations_receiver: new_animations_receiver,
outstanding_web_fonts: outstanding_web_fonts_counter,
root_flow: None,
running_animations: Arc::new(RwLock::new(HashMap::new())),
expired_animations: Arc::new(RwLock::new(HashMap::new())),
epoch: Epoch(0),
viewport_size: Size2D::new(Au(0), Au(0)),
webrender_api: webrender_api_sender.create_api(),
rw_data: Arc::new(Mutex::new(
LayoutThreadData {
constellation_chan: constellation_chan,
display_list: None,
stylist: stylist,
content_box_response: Rect::zero(),
content_boxes_response: Vec::new(),
client_rect_response: Rect::zero(),
hit_test_response: (None, false),
scroll_area_response: Rect::zero(),
overflow_response: NodeOverflowResponse(None),
resolved_style_response: None,
offset_parent_response: OffsetParentResponse::empty(),
margin_style_response: MarginStyleResponse::empty(),
stacking_context_scroll_offsets: HashMap::new(),
})),
error_reporter: CSSErrorReporter {
pipelineid: id,
script_chan: Arc::new(Mutex::new(script_chan)),
},
webrender_image_cache:
Arc::new(RwLock::new(HashMap::with_hasher(Default::default()))),
timer:
if PREFS.get("layout.animations.test.enabled")
.as_boolean().unwrap_or(false) {
Timer::test_mode()
} else {
Timer::new()
},
layout_threads: layout_threads,
}
}
/// 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_shared_layout_context(&self,
rw_data: &LayoutThreadData,
screen_size_changed: bool,
goal: ReflowGoal)
-> SharedLayoutContext {
let local_style_context_creation_data = LocalStyleContextCreationInfo::new(self.new_animations_sender.clone());
SharedLayoutContext {
style_context: SharedStyleContext {
viewport_size: self.viewport_size.clone(),
screen_size_changed: screen_size_changed,
stylist: rw_data.stylist.clone(),
generation: self.generation,
goal: goal,
running_animations: self.running_animations.clone(),
expired_animations: self.expired_animations.clone(),
error_reporter: self.error_reporter.clone(),
local_context_creation_data: Mutex::new(local_style_context_creation_data),
timer: self.timer.clone(),
},
image_cache_thread: Mutex::new(self.image_cache_thread.clone()),
image_cache_sender: Mutex::new(self.image_cache_sender.clone()),
font_cache_thread: Mutex::new(self.font_cache_thread.clone()),
webrender_image_cache: self.webrender_image_cache.clone(),
}
}
/// 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),
FromImageCache,
FromFontCache,
}
let request = {
let port_from_script = &self.port;
let port_from_pipeline = &self.pipeline_port;
let port_from_image_cache = &self.image_cache_receiver;
let port_from_font_cache = &self.font_cache_receiver;
select! {
msg = port_from_pipeline.recv() => {
Request::FromPipeline(msg.unwrap())
},
msg = port_from_script.recv() => {
Request::FromScript(msg.unwrap())
},
msg = port_from_image_cache.recv() => {
msg.unwrap();
Request::FromImageCache
},
msg = port_from_font_cache.recv() => {
msg.unwrap();
Request::FromFontCache
}
}
};
match request {
Request::FromPipeline(LayoutControlMsg::SetStackingContextScrollStates(
new_scroll_states)) => {
self.handle_request_helper(Msg::SetStackingContextScrollStates(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::FromScript(msg) => {
self.handle_request_helper(msg, possibly_locked_rw_data)
},
Request::FromImageCache => {
self.repaint(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
},
}
}
/// Repaint the scene, without performing style matching. This is typically
/// used when an image arrives asynchronously and triggers a relayout and
/// repaint.
/// TODO: In the future we could detect if the image size hasn't changed
/// since last time and avoid performing a complete layout pass.
fn repaint<'a, 'b>(&mut self, possibly_locked_rw_data: &mut RwData<'a, 'b>) -> bool {
let mut rw_data = possibly_locked_rw_data.lock();
if let Some(mut root_flow) = self.root_flow.clone() {
let flow = flow::mut_base(FlowRef::deref_mut(&mut root_flow));
flow.restyle_damage.insert(REPAINT);
}
let reflow_info = Reflow {
goal: ReflowGoal::ForDisplay,
page_clip_rect: max_rect(),
};
let mut layout_context = self.build_shared_layout_context(&*rw_data,
false,
reflow_info.goal);
self.perform_post_style_recalc_layout_passes(&reflow_info,
None,
None,
&mut *rw_data,
&mut layout_context);
true
}
/// 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 {
match request {
Msg::AddStylesheet(style_info) => {
self.handle_add_stylesheet(style_info, possibly_locked_rw_data)
}
Msg::SetQuirksMode => self.handle_set_quirks_mode(possibly_locked_rw_data),
Msg::GetRPC(response_chan) => {
response_chan.send(box LayoutRPCImpl(self.rw_data.clone()) as
Box<LayoutRPC + Send>).unwrap();
},
Msg::Reflow(data) => {
profile(time::ProfilerCategory::LayoutPerform,
self.profiler_metadata(),
self.time_profiler_chan.clone(),
|| self.handle_reflow(&data, possibly_locked_rw_data));
},
Msg::TickAnimations => self.tick_all_animations(possibly_locked_rw_data),
Msg::ReflowWithNewlyLoadedWebFont => {
self.reflow_with_newly_loaded_web_font(possibly_locked_rw_data)
}
Msg::SetStackingContextScrollStates(new_scroll_states) => {
self.set_stacking_context_scroll_states(new_scroll_states,
possibly_locked_rw_data);
}
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).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::PrepareToExit(response_chan) => {
self.prepare_to_exit(response_chan);
return false
},
Msg::ExitNow => {
debug!("layout: ExitNow received");
self.exit_now();
return false
}
}
true
}
fn collect_reports<'a, 'b>(&self,
reports_chan: ReportsChan,
possibly_locked_rw_data: &mut RwData<'a, 'b>) {
let mut reports = vec![];
// 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.heap_size_of_children()),
});
let stylist = rw_data.stylist.as_ref();
reports.push(Report {
path: path![formatted_url, "layout-thread", "stylist"],
kind: ReportKind::ExplicitJemallocHeapSize,
size: stylist.heap_size_of_children(),
});
// The LayoutThread has a context in TLS...
reports.push(Report {
path: path![formatted_url, "layout-thread", "local-context"],
kind: ReportKind::ExplicitJemallocHeapSize,
size: heap_size_of_local_context(),
});
reports_chan.send(reports);
}
fn create_layout_thread(&self, info: NewLayoutThreadInfo) {
LayoutThread::create(info.id,
FrameId::installed(),
info.url.clone(),
info.is_parent,
info.layout_pair,
info.pipeline_port,
info.constellation_chan,
info.script_chan.clone(),
self.image_cache_thread.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(),
info.layout_threads);
}
/// 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 rayon threadpool if present.
let _ = self.parallel_traversal.take();
}
fn handle_add_stylesheet<'a, 'b>(&self,
stylesheet: Arc<Stylesheet>,
possibly_locked_rw_data: &mut RwData<'a, 'b>) {
// Find all font-face rules and notify the font cache of them.
// GWTODO: Need to handle unloading web fonts.
let rw_data = possibly_locked_rw_data.lock();
if stylesheet.is_effective_for_device(&rw_data.stylist.device) {
add_font_face_rules(&*stylesheet,
&rw_data.stylist.device,
&self.font_cache_thread,
&self.font_cache_sender,
&self.outstanding_web_fonts);
}
possibly_locked_rw_data.block(rw_data);
}
/// 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>(&self, possibly_locked_rw_data: &mut RwData<'a, 'b>) {
let mut rw_data = possibly_locked_rw_data.lock();
Arc::get_mut(&mut rw_data.stylist).unwrap().set_quirks_mode(true);
possibly_locked_rw_data.block(rw_data);
}
fn try_get_layout_root<N: LayoutNode>(&self, node: N) -> Option<FlowRef> {
let mut data = match node.mutate_layout_data() {
Some(x) => x,
None => return None,
};
let result = data.flow_construction_result.swap_out();
let mut flow = match result {
ConstructionResult::Flow(mut flow, abs_descendants) => {
// Note: Assuming that the root has display 'static' (as per
// CSS Section 9.3.1). Otherwise, if it were absolutely
// positioned, it would return a reference to itself in
// `abs_descendants` and would lead to a circular reference.
// Set Root as CB for any remaining absolute descendants.
flow.set_absolute_descendants(abs_descendants);
flow
}
_ => return None,
};
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 Flow,
shared_layout_context: &SharedLayoutContext) {
let _scope = layout_debug_scope!("solve_constraints");
sequential::traverse_flow_tree_preorder(layout_root, shared_layout_context);
}
/// Performs layout constraint solving in parallel.
///
/// This corresponds to `Reflow()` in Gecko and `layout()` in WebKit/Blink and should be
/// benchmarked against those two. It is marked `#[inline(never)]` to aid profiling.
#[inline(never)]
fn solve_constraints_parallel(traversal: &rayon::ThreadPool,
layout_root: &mut Flow,
profiler_metadata: Option<TimerMetadata>,
time_profiler_chan: time::ProfilerChan,
shared_layout_context: &SharedLayoutContext) {
let _scope = layout_debug_scope!("solve_constraints_parallel");
// NOTE: this currently computes borders, so any pruning should separate that
// operation out.
parallel::traverse_flow_tree_preorder(layout_root,
profiler_metadata,
time_profiler_chan,
shared_layout_context,
traversal);
}
/// Computes the stacking-relative positions of all flows and, if the painting is dirty and the
/// reflow goal and query type need it, builds the display list.
fn compute_abs_pos_and_build_display_list(&mut self,
data: &Reflow,
query_type: Option<&ReflowQueryType>,
document: Option<&ServoLayoutDocument>,
layout_root: &mut Flow,
shared_layout_context: &mut SharedLayoutContext,
rw_data: &mut LayoutThreadData) {
let writing_mode = flow::base(layout_root).writing_mode;
let (metadata, sender) = (self.profiler_metadata(), self.time_profiler_chan.clone());
profile(time::ProfilerCategory::LayoutDispListBuild,
metadata.clone(),
sender.clone(),
|| {
flow::mut_base(layout_root).stacking_relative_position =
LogicalPoint::zero(writing_mode).to_physical(writing_mode,
self.viewport_size);
flow::mut_base(layout_root).clip =
ClippingRegion::from_rect(&data.page_clip_rect);
if flow::base(layout_root).restyle_damage.contains(REPOSITION) {
layout_root.traverse_preorder(&ComputeAbsolutePositions {
layout_context: shared_layout_context
});
}
if flow::base(layout_root).restyle_damage.contains(REPAINT) ||
rw_data.display_list.is_none() {
let display_list_needed = query_type.map(reflow_query_type_needs_display_list)
.unwrap_or(false);
match (data.goal, display_list_needed) {
(ReflowGoal::ForDisplay, _) | (ReflowGoal::ForScriptQuery, true) => {
let mut build_state =
sequential::build_display_list_for_subtree(layout_root,
shared_layout_context);
debug!("Done building display list.");
let root_size = {
let root_flow = flow::base(layout_root);
if rw_data.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);
build_state.root_stacking_context.bounds = origin;
build_state.root_stacking_context.overflow = origin;
rw_data.display_list = Some(Arc::new(build_state.to_display_list()));
}
(ReflowGoal::ForScriptQuery, false) => {}
}
}
if data.goal != ReflowGoal::ForDisplay {
// 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 pipeline_id = self.id.to_webrender();
let mut frame_builder = WebRenderFrameBuilder::new(pipeline_id);
let built_display_list = rw_data.display_list.as_ref().unwrap().convert_to_webrender(
&mut frame_builder);
let viewport_size = Size2D::new(self.viewport_size.width.to_f32_px(),
self.viewport_size.height.to_f32_px());
self.epoch.next();
let Epoch(epoch_number) = self.epoch;
self.webrender_api.set_root_display_list(
get_root_flow_background_color(layout_root),
webrender_traits::Epoch(epoch_number),
pipeline_id,
viewport_size,
built_display_list,
frame_builder.auxiliary_lists_builder.finalize());
});
}
/// The high-level routine that performs layout threads.
fn handle_reflow<'a, 'b>(&mut self,
data: &ScriptReflow,
possibly_locked_rw_data: &mut RwData<'a, 'b>) {
let document = unsafe { ServoLayoutNode::new(&data.document) };
let document = document.as_document().unwrap();
// FIXME(pcwalton): Combine `ReflowGoal` and `ReflowQueryType`. Then remove this assert.
debug_assert!((data.reflow_info.goal == ReflowGoal::ForDisplay &&
data.query_type == ReflowQueryType::NoQuery) ||
(data.reflow_info.goal == ReflowGoal::ForScriptQuery &&
data.query_type != ReflowQueryType::NoQuery));
let mut rw_data = possibly_locked_rw_data.lock();
let element: ServoLayoutElement = match document.root_node() {
None => {
// Since we cannot compute anything, give spec-required placeholders.
debug!("layout: No root node: bailing");
match data.query_type {
ReflowQueryType::ContentBoxQuery(_) => {
rw_data.content_box_response = Rect::zero();
},
ReflowQueryType::ContentBoxesQuery(_) => {
rw_data.content_boxes_response = Vec::new();
},
ReflowQueryType::HitTestQuery(..) => {
rw_data.hit_test_response = (None, false);
},
ReflowQueryType::NodeGeometryQuery(_) => {
rw_data.client_rect_response = Rect::zero();
},
ReflowQueryType::NodeScrollGeometryQuery(_) => {
rw_data.scroll_area_response = Rect::zero();
},
ReflowQueryType::NodeOverflowQuery(_) => {
rw_data.overflow_response = NodeOverflowResponse(None);
},
ReflowQueryType::ResolvedStyleQuery(_, _, _) => {
rw_data.resolved_style_response = None;
},
ReflowQueryType::OffsetParentQuery(_) => {
rw_data.offset_parent_response = OffsetParentResponse::empty();
},
ReflowQueryType::MarginStyleQuery(_) => {
rw_data.margin_style_response = MarginStyleResponse::empty();
},
ReflowQueryType::NoQuery => {}
}
return;
},
Some(x) => x.as_element().unwrap(),
};
debug!("layout: processing reflow request for: {:?} ({}) (query={:?})",
element, self.url, data.query_type);
if log_enabled!(log::LogLevel::Debug) {
element.as_node().dump();
}
let initial_viewport = data.window_size.initial_viewport;
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
let device = Device::new(MediaType::Screen, initial_viewport);
Arc::get_mut(&mut rw_data.stylist).unwrap().set_device(device, &data.document_stylesheets);
let constraints = rw_data.stylist.viewport_constraints().clone();
self.viewport_size = match constraints {
Some(ref 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))
}
None => current_screen_size,
};
// Handle conditions where the entire flow tree is invalid.
let mut needs_dirtying = false;
let viewport_size_changed = self.viewport_size != old_viewport_size;
if viewport_size_changed {
if let Some(constraints) = constraints {
// let the constellation know about the viewport constraints
rw_data.constellation_chan
.send(ConstellationMsg::ViewportConstrained(self.id, constraints))
.unwrap();
}
if data.document_stylesheets.iter().any(|sheet| sheet.dirty_on_viewport_size_change()) {
let mut iter = element.as_node().traverse_preorder();
let mut next = iter.next();
while let Some(node) = next {
if node.needs_dirty_on_viewport_size_changed() {
let el = node.as_element().unwrap();
el.mutate_data().map(|mut d| d.restyle()
.map(|mut r| r.hint.insert(&StoredRestyleHint::subtree())));
if let Some(p) = el.parent_element() {
unsafe { p.note_dirty_descendant() };
}
next = iter.next_skipping_children();
} else {
next = iter.next();
}
}
}
}
// If the entire flow tree is invalid, then it will be reflowed anyhow.
needs_dirtying |= Arc::get_mut(&mut rw_data.stylist).unwrap().update(&data.document_stylesheets,
Some(&*UA_STYLESHEETS),
data.stylesheets_changed);
let needs_reflow = viewport_size_changed && !needs_dirtying;
if needs_dirtying {
element.mutate_data().map(|mut d| d.restyle().map(|mut r| r.hint.insert(&StoredRestyleHint::subtree())));
}
if needs_reflow {
if let Some(mut flow) = self.try_get_layout_root(element.as_node()) {
LayoutThread::reflow_all_nodes(FlowRef::deref_mut(&mut flow));
}
}
let restyles = document.drain_pending_restyles();
debug!("Draining restyles: {}", restyles.len());
if !needs_dirtying {
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 mut data = match el.mutate_layout_data() {
Some(d) => d,
None => continue,
};
let mut style_data = &mut data.base.style_data;
debug_assert!(!style_data.is_restyle());
let mut restyle_data = match style_data.restyle() {
Some(d) => d,
None => continue,
};
// Stash the data on the element for processing by the style system.
restyle_data.hint = restyle.hint.into();
restyle_data.damage = restyle.damage;
restyle_data.snapshot = restyle.snapshot;
debug!("Noting restyle for {:?}: {:?}", el, restyle_data);
}
}
// Create a layout context for use throughout the following passes.
let mut shared_layout_context = self.build_shared_layout_context(&*rw_data,
viewport_size_changed,
data.reflow_info.goal);
if element.styling_mode() != StylingMode::Stop {
// Recalculate CSS styles and rebuild flows and fragments.
profile(time::ProfilerCategory::LayoutStyleRecalc,
self.profiler_metadata(),
self.time_profiler_chan.clone(),
|| {
// Perform CSS selector matching and flow construction.
match self.parallel_traversal {
None => {
sequential::traverse_dom::<ServoLayoutNode, RecalcStyleAndConstructFlows>(
element.as_node(), &shared_layout_context);
}
Some(ref mut traversal) => {
parallel::traverse_dom::<ServoLayoutNode, RecalcStyleAndConstructFlows>(
element.as_node(), &shared_layout_context, traversal);
}
}
});
// TODO(pcwalton): Measure energy usage of text shaping, perhaps?
let text_shaping_time =
(font::get_and_reset_text_shaping_performance_counter() as u64) /
(self.layout_threads as u64);
time::send_profile_data(time::ProfilerCategory::LayoutTextShaping,
self.profiler_metadata(),
self.time_profiler_chan.clone(),
0,
text_shaping_time,
0,
0);
// Retrieve the (possibly rebuilt) root flow.
self.root_flow = self.try_get_layout_root(element.as_node());
}
if opts::get().dump_style_tree {
element.as_node().dump_style();
}
if opts::get().dump_rule_tree {
shared_layout_context.style_context.stylist.rule_tree.dump_stdout();
}
// GC the rule tree if some heuristics are met.
unsafe { shared_layout_context.style_context.stylist.rule_tree.maybe_gc(); }
// Perform post-style recalculation layout passes.
self.perform_post_style_recalc_layout_passes(&data.reflow_info,
Some(&data.query_type),
Some(&document),
&mut rw_data,
&mut shared_layout_context);
self.respond_to_query_if_necessary(&data.query_type,
&mut *rw_data,
&mut shared_layout_context);
}
fn respond_to_query_if_necessary(&mut self,
query_type: &ReflowQueryType,
rw_data: &mut LayoutThreadData,
shared_layout_context: &mut SharedLayoutContext) {
let mut root_flow = match self.root_flow.clone() {
Some(root_flow) => root_flow,
None => return,
};
let root_flow = FlowRef::deref_mut(&mut root_flow);
match *query_type {
ReflowQueryType::ContentBoxQuery(node) => {
let node = unsafe { ServoLayoutNode::new(&node) };
rw_data.content_box_response = process_content_box_request(node, root_flow);
},
ReflowQueryType::ContentBoxesQuery(node) => {
let node = unsafe { ServoLayoutNode::new(&node) };
rw_data.content_boxes_response = process_content_boxes_request(node, root_flow);
},
ReflowQueryType::HitTestQuery(translated_point, client_point, update_cursor) => {
let translated_point = Point2D::new(Au::from_f32_px(translated_point.x),
Au::from_f32_px(translated_point.y));
let client_point = Point2D::new(Au::from_f32_px(client_point.x),
Au::from_f32_px(client_point.y));
let result = rw_data.display_list
.as_ref()
.expect("Tried to hit test with no display list")
.hit_test(&translated_point,
&client_point,
&rw_data.stacking_context_scroll_offsets);
rw_data.hit_test_response = (result.last().cloned(), update_cursor);
},
ReflowQueryType::NodeGeometryQuery(node) => {
let node = unsafe { ServoLayoutNode::new(&node) };
rw_data.client_rect_response = process_node_geometry_request(node, root_flow);
},
ReflowQueryType::NodeScrollGeometryQuery(node) => {
let node = unsafe { ServoLayoutNode::new(&node) };
rw_data.scroll_area_response = process_node_scroll_area_request(node, root_flow);
},
ReflowQueryType::NodeOverflowQuery(node) => {
let node = unsafe { ServoLayoutNode::new(&node) };
rw_data.overflow_response = process_node_overflow_request(node);
},
ReflowQueryType::ResolvedStyleQuery(node, ref pseudo, ref property) => {
let node = unsafe { ServoLayoutNode::new(&node) };
let layout_context = LayoutContext::new(&shared_layout_context);
rw_data.resolved_style_response =
process_resolved_style_request(node,
&layout_context,
pseudo,
property,
root_flow);
},
ReflowQueryType::OffsetParentQuery(node) => {
let node = unsafe { ServoLayoutNode::new(&node) };
rw_data.offset_parent_response = process_offset_parent_query(node, root_flow);
},
ReflowQueryType::MarginStyleQuery(node) => {
let node = unsafe { ServoLayoutNode::new(&node) };
rw_data.margin_style_response = process_margin_style_query(node);
},
ReflowQueryType::NoQuery => {}
}
}
fn set_stacking_context_scroll_states<'a, 'b>(
&mut self,
new_scroll_states: Vec<StackingContextScrollState>,
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_scroll_state in &new_scroll_states {
let offset = new_scroll_state.scroll_offset;
layout_scroll_states.insert(new_scroll_state.scroll_root_id, offset);
if new_scroll_state.scroll_root_id == ScrollRootId::root() {
script_scroll_states.push((UntrustedNodeAddress::from_id(0), offset))
} else if !new_scroll_state.scroll_root_id.is_special() &&
new_scroll_state.scroll_root_id.fragment_type() == FragmentType::FragmentBody {
let id = new_scroll_state.scroll_root_id.id();
script_scroll_states.push((UntrustedNodeAddress::from_id(id), offset))
}
}
let _ = self.script_chan
.send(ConstellationControlMsg::SetScrollState(self.id, script_scroll_states));
rw_data.stacking_context_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) {
let reflow_info = Reflow {
goal: ReflowGoal::ForDisplay,
page_clip_rect: max_rect(),
};
let mut layout_context = self.build_shared_layout_context(&*rw_data,
false,
reflow_info.goal);
if let Some(mut root_flow) = self.root_flow.clone() {
// Perform an abbreviated style recalc that operates without access to the DOM.
let animations = self.running_animations.read();
profile(time::ProfilerCategory::LayoutStyleRecalc,
self.profiler_metadata(),
self.time_profiler_chan.clone(),
|| {
animation::recalc_style_for_animations(&layout_context,
FlowRef::deref_mut(&mut root_flow),
&animations)
});
}
self.perform_post_style_recalc_layout_passes(&reflow_info,
None,
None,
&mut *rw_data,
&mut layout_context);
}
fn reflow_with_newly_loaded_web_font<'a, 'b>(&mut self, possibly_locked_rw_data: &mut RwData<'a, 'b>) {
let mut rw_data = possibly_locked_rw_data.lock();
font_context::invalidate_font_caches();
let reflow_info = Reflow {
goal: ReflowGoal::ForDisplay,
page_clip_rect: max_rect(),
};
let mut layout_context = self.build_shared_layout_context(&*rw_data,
false,
reflow_info.goal);
// No need to do a style recalc here.
if self.root_flow.is_none() {
return
}
self.perform_post_style_recalc_layout_passes(&reflow_info,
None,
None,
&mut *rw_data,
&mut layout_context);
}
fn perform_post_style_recalc_layout_passes(&mut self,
data: &Reflow,
query_type: Option<&ReflowQueryType>,
document: Option<&ServoLayoutDocument>,
rw_data: &mut LayoutThreadData,
layout_context: &mut SharedLayoutContext) {
if let Some(mut root_flow) = self.root_flow.clone() {
// Kick off animations if any were triggered, expire completed ones.
animation::update_animation_state(&self.constellation_chan,
&self.script_chan,
&mut *self.running_animations.write(),
&mut *self.expired_animations.write(),
&self.new_animations_receiver,
self.id,
&self.timer);
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(&mut root_flow).compute_layout_damage();
if opts::get().nonincremental_layout || damage.contains(REFLOW_ENTIRE_DOCUMENT) {
FlowRef::deref_mut(&mut root_flow).reflow_entire_document()
}
});
if opts::get().trace_layout {
layout_debug::begin_trace(root_flow.clone());
}
// Resolve generated content.
profile(time::ProfilerCategory::LayoutGeneratedContent,
self.profiler_metadata(),
self.time_profiler_chan.clone(),
|| sequential::resolve_generated_content(FlowRef::deref_mut(&mut root_flow), &layout_context));
// Guess float placement.
profile(time::ProfilerCategory::LayoutFloatPlacementSpeculation,
self.profiler_metadata(),
self.time_profiler_chan.clone(),
|| sequential::guess_float_placement(FlowRef::deref_mut(&mut root_flow)));
// Perform the primary layout passes over the flow tree to compute the locations of all
// the boxes.
if flow::base(&*root_flow).restyle_damage.intersects(REFLOW | REFLOW_OUT_OF_FLOW) {
profile(time::ProfilerCategory::LayoutMain,
self.profiler_metadata(),
self.time_profiler_chan.clone(),
|| {
let profiler_metadata = self.profiler_metadata();
match self.parallel_traversal {
None => {
// Sequential mode.
LayoutThread::solve_constraints(FlowRef::deref_mut(&mut root_flow), &layout_context)
}
Some(ref mut parallel) => {
// Parallel mode.
LayoutThread::solve_constraints_parallel(parallel,
FlowRef::deref_mut(&mut root_flow),
profiler_metadata,
self.time_profiler_chan.clone(),
&*layout_context);
}
}
});
}
profile(time::ProfilerCategory::LayoutStoreOverflow,
self.profiler_metadata(),
self.time_profiler_chan.clone(),
|| {
let layout_context = LayoutContext::new(&*layout_context);
sequential::store_overflow(&layout_context,
FlowRef::deref_mut(&mut root_flow) as &mut Flow);
});
self.perform_post_main_layout_passes(data,
query_type,
document,
rw_data,
layout_context);
}
}
fn perform_post_main_layout_passes(&mut self,
data: &Reflow,
query_type: Option<&ReflowQueryType>,
document: Option<&ServoLayoutDocument>,
rw_data: &mut LayoutThreadData,
layout_context: &mut SharedLayoutContext) {
// Build the display list if necessary, and send it to the painter.
if let Some(mut root_flow) = self.root_flow.clone() {
self.compute_abs_pos_and_build_display_list(data,
query_type,
document,
FlowRef::deref_mut(&mut root_flow),
&mut *layout_context,
rw_data);
self.first_reflow = false;
if opts::get().trace_layout {
layout_debug::end_trace(self.generation);
}
if opts::get().dump_flow_tree {
root_flow.print("Post layout flow tree".to_owned());
}
self.generation += 1;
}
}
fn reflow_all_nodes(flow: &mut Flow) {
debug!("reflowing all nodes!");
flow::mut_base(flow).restyle_damage.insert(REPAINT | STORE_OVERFLOW | REFLOW);
for child in flow::child_iter_mut(flow) {
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 {
TimerMetadataReflowType::FirstReflow
} else {
TimerMetadataReflowType::Incremental
},
})
}
}
// The default computed value for background-color is transparent (see
// http://dev.w3.org/csswg/css-backgrounds/#background-color). However, we
// need to propagate the background color from the root HTML/Body
// element (http://dev.w3.org/csswg/css-backgrounds/#special-backgrounds) if
// it is non-transparent. The phrase in the spec "If the canvas background
// is not opaque, what shows through is UA-dependent." is handled by rust-layers
// clearing the frame buffer to white. This ensures that setting a background
// color on an iframe element, while the iframe content itself has a default
// transparent background color is handled correctly.
fn get_root_flow_background_color(flow: &mut Flow) -> webrender_traits::ColorF {
let transparent = webrender_traits::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();
kid_block_flow.fragment
.style
.resolve_color(kid_block_flow.fragment.style.get_background().background_color)
.to_gfx_color()
}
fn get_ua_stylesheets() -> Result<UserAgentStylesheets, &'static str> {
fn parse_ua_stylesheet(filename: &'static str) -> Result<Stylesheet, &'static str> {
let res = try!(read_resource_file(filename).map_err(|_| filename));
Ok(Stylesheet::from_bytes(
&res,
ServoUrl::parse(&format!("chrome://resources/{:?}", filename)).unwrap(),
None,
None,
Origin::UserAgent,
Default::default(),
Box::new(StdoutErrorReporter),
ParserContextExtraData::default()))
}
let mut user_or_user_agent_stylesheets = vec!();
// FIXME: presentational-hints.css should be at author origin with zero specificity.
// (Does it make a difference?)
for &filename in &["user-agent.css", "servo.css", "presentational-hints.css"] {
user_or_user_agent_stylesheets.push(try!(parse_ua_stylesheet(filename)));
}
for &(ref contents, ref url) in &opts::get().user_stylesheets {
user_or_user_agent_stylesheets.push(Stylesheet::from_bytes(
&contents, url.clone(), None, None, Origin::User, Default::default(),
Box::new(StdoutErrorReporter), ParserContextExtraData::default()));
}
let quirks_mode_stylesheet = try!(parse_ua_stylesheet("quirks-mode.css"));
Ok(UserAgentStylesheets {
user_or_user_agent_stylesheets: user_or_user_agent_stylesheets,
quirks_mode_stylesheet: quirks_mode_stylesheet,
})
}
/// Returns true if the given reflow query type needs a full, up-to-date display list to be present
/// or false if it only needs stacking-relative positions.
fn reflow_query_type_needs_display_list(query_type: &ReflowQueryType) -> bool {
match *query_type {
ReflowQueryType::HitTestQuery(..) => true,
ReflowQueryType::ContentBoxQuery(_) | ReflowQueryType::ContentBoxesQuery(_) |
ReflowQueryType::NodeGeometryQuery(_) | ReflowQueryType::NodeScrollGeometryQuery(_) |
ReflowQueryType::NodeOverflowQuery(_) | ReflowQueryType::ResolvedStyleQuery(..) |
ReflowQueryType::OffsetParentQuery(_) | ReflowQueryType::MarginStyleQuery(_) |
ReflowQueryType::NoQuery => false,
}
}
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);
}
}
};
}