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servo/components/layout_thread/lib.rs
Josh Matthews c890c9143c Make script thread initiate requests for images needed by layout. 
In support of this goal, the layout thread collects information about
CSS images that are missing image data and hands it off to the script
thread after layout completes. The script thread stores a list of
nodes that will need to be reflowed after the associated network
request is complete. The script thread ensures that the nodes are
not GCed while a request is ongoing, which the layout thread is
incapable of guaranteeing.

The image cache's API has also been redesigned in support of this
work. No network requests are made by the new image cache, since it
does not possess the document-specific information necessary to
initiate them. Instead, there is now a single, synchronous
query operation that optionally reserves a slot when a cache
entry for a URL cannot be found. This reserved slot is then
the responsibility of the queryer to populate with the contents
of the network response for the URL once it is complete. Any
subsequent queries for the same URL will be informed that the
response is pending until that occurs.

The changes to layout also remove the synchronous image loading
code path, which means that reftests now test the same code
that non-test binaries execute. The decision to take a screenshot
now considers whether there are any outstanding image
requests for layout in order to avoid intermittent failures in
reftests that use CSS images.
2017-02-22 14:19:35 -05:00

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/* 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)]
extern crate app_units;
extern crate euclid;
extern crate fnv;
extern crate gfx;
extern crate gfx_traits;
extern crate heapsize;
extern crate ipc_channel;
#[macro_use]
extern crate layout;
extern crate layout_traits;
#[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_config;
extern crate servo_geometry;
extern crate servo_url;
extern crate style;
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;
use layout::context::heap_size_of_persistent_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_node_scroll_root_id_request, process_offset_parent_query};
use layout::sequential;
use layout::traversal::{ComputeAbsolutePositions, RecalcStyleAndConstructFlows};
use layout::webrender_helpers::WebRenderDisplayListConverter;
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::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::rpc::TextIndexResponse;
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_config::opts;
use servo_config::prefs::PREFS;
use servo_config::resource_files::read_resource_file;
use servo_geometry::max_rect;
use servo_url::ServoUrl;
use std::borrow::ToOwned;
use std::collections::HashMap;
use std::hash::BuildHasherDefault;
use std::mem as std_mem;
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 std::thread;
use style::animation::Animation;
use style::context::{QuirksMode, ReflowGoal, SharedStyleContext, ThreadLocalStyleContextCreationInfo};
use style::data::StoredRestyleHint;
use style::dom::{ShowSubtree, ShowSubtreeDataAndPrimaryValues, 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::properties::ComputedValues;
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 style::traversal::{DomTraversal, TraversalDriver};
/// 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 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>,
/// 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: 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 `servo_config::opts`, but we'd
// rather limit the dependency on that module here.
layout_threads: usize,
/// Which quirks mode are we rendering the document in?
quirks_mode: Option<QuirksMode>
}
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: Option<IpcSender<()>>,
webrender_api_sender: webrender_traits::RenderApiSender,
layout_threads: usize) {
thread::Builder::new().name(format!("LayoutThread {:?}", id)).spawn(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);
}
if let Some(content_process_shutdown_chan) = content_process_shutdown_chan {
let _ = content_process_shutdown_chan.send(());
}
}).expect("Thread spawning failed");
}
}
/// 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 configuration =
rayon::Configuration::new().set_num_threads(layout_threads);
let parallel_traversal = rayon::ThreadPool::new(configuration).ok();
debug!("Possible layout Threads: {}", layout_threads);
// 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 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,
font_cache_receiver: font_cache_receiver,
font_cache_sender: ipc_font_cache_sender,
parallel_traversal: parallel_traversal,
parallel_flag: true,
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: None,
content_boxes_response: Vec::new(),
client_rect_response: Rect::zero(),
hit_test_response: (None, false),
scroll_root_id_response: None,
scroll_area_response: Rect::zero(),
overflow_response: NodeOverflowResponse(None),
resolved_style_response: String::new(),
offset_parent_response: OffsetParentResponse::empty(),
margin_style_response: MarginStyleResponse::empty(),
stacking_context_scroll_offsets: HashMap::new(),
text_index_response: TextIndexResponse(None),
pending_images: vec![],
})),
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,
quirks_mode: None,
}
}
/// 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(&self,
rw_data: &LayoutThreadData,
screen_size_changed: bool,
goal: ReflowGoal)
-> LayoutContext {
let thread_local_style_context_creation_data =
ThreadLocalStyleContextCreationInfo::new(self.new_animations_sender.clone());
LayoutContext {
style_context: SharedStyleContext {
viewport_size: self.viewport_size.clone(),
screen_size_changed: screen_size_changed,
stylist: rw_data.stylist.clone(),
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(thread_local_style_context_creation_data),
timer: self.timer.clone(),
quirks_mode: self.quirks_mode.unwrap(),
// FIXME(bz): This isn't really right, but it's no more wrong
// than what we used to do. See
// https://github.com/servo/servo/issues/14773 for fixing it
// properly.
default_computed_values: Arc::new(ComputedValues::initial_values().clone()),
},
image_cache_thread: Mutex::new(self.image_cache_thread.clone()),
font_cache_thread: Mutex::new(self.font_cache_thread.clone()),
webrender_image_cache: self.webrender_image_cache.clone(),
pending_images: Mutex::new(vec![]),
}
}
/// 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,
}
let request = {
let port_from_script = &self.port;
let port_from_pipeline = &self.pipeline_port;
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_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::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
},
}
}
/// 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 data in Persistent TLS...
reports.push(Report {
path: path![formatted_url, "layout-thread", "local-context"],
kind: ReportKind::ExplicitJemallocHeapSize,
size: heap_size_of_persistent_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,
layout_context: &LayoutContext) {
let _scope = layout_debug_scope!("solve_constraints");
sequential::traverse_flow_tree_preorder(layout_root, 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,
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::traverse_flow_tree_preorder(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 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,
layout_context: &mut LayoutContext,
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: 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,
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;
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![]);
let msg = ConstellationMsg::FrameSizes(iframe_sizes);
if let Err(e) = self.constellation_chan.send(msg) {
warn!("Layout resize to constellation failed ({}).", e);
}
}
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 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());
self.epoch.next();
let Epoch(epoch_number) = self.epoch;
let viewport_size = webrender_traits::LayoutSize::from_untyped(&viewport_size);
self.webrender_api.set_root_display_list(
Some(get_root_flow_background_color(layout_root)),
webrender_traits::Epoch(epoch_number),
viewport_size,
builder,
true);
self.webrender_api.generate_frame(None);
});
}
/// 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();
self.quirks_mode = Some(document.quirks_mode());
// 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));
// Parallelize if there's more than 750 objects based on rzambre's suggestion
// https://github.com/servo/servo/issues/10110
self.parallel_flag = self.layout_threads > 1 && 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();
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 = None;
},
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::NodeScrollRootIdQuery(_) => {
rw_data.scroll_root_id_response = None;
},
ReflowQueryType::ResolvedStyleQuery(_, _, _) => {
rw_data.resolved_style_response = String::new();
},
ReflowQueryType::OffsetParentQuery(_) => {
rw_data.offset_parent_response = OffsetParentResponse::empty();
},
ReflowQueryType::MarginStyleQuery(_) => {
rw_data.margin_style_response = MarginStyleResponse::empty();
},
ReflowQueryType::TextIndexQuery(..) => {
rw_data.text_index_response = TextIndexResponse(None);
}
ReflowQueryType::NoQuery => {}
}
return;
},
Some(x) => x.as_element().unwrap(),
};
debug!("layout: processing reflow request for: {:?} ({}) (query={:?})",
element, self.url, data.query_type);
debug!("{:?}", ShowSubtree(element.as_node()));
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 § 6
let device = Device::new(MediaType::Screen, initial_viewport);
Arc::get_mut(&mut rw_data.stylist).unwrap().set_device(device, &data.document_stylesheets);
self.viewport_size =
rw_data.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))
});
// 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) = rw_data.stylist.viewport_constraints() {
// let the constellation know about the viewport constraints
rw_data.constellation_chan
.send(ConstellationMsg::ViewportConstrained(self.id, constraints.clone()))
.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();
if let Some(mut d) = element.mutate_data() {
if d.has_styles() {
d.ensure_restyle().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 {
if let Some(mut d) = element.mutate_data() {
if d.has_styles() {
d.ensure_restyle().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: {} (needs dirtying? {:?})", restyles.len(), needs_dirtying);
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.has_current_styles());
let mut restyle_data = style_data.ensure_restyle();
// Stash the data on the element for processing by the style system.
restyle_data.hint = restyle.hint.into();
restyle_data.damage = restyle.damage;
if let Some(s) = restyle.snapshot {
restyle_data.snapshot.ensure(move || s);
}
debug!("Noting restyle for {:?}: {:?}", el, restyle_data);
}
}
// Create a layout context for use throughout the following passes.
let mut layout_context = self.build_layout_context(&*rw_data,
viewport_size_changed,
data.reflow_info.goal);
// NB: Type inference falls apart here for some reason, so we need to be very verbose. :-(
let traversal_driver = if self.parallel_flag && self.parallel_traversal.is_some() {
TraversalDriver::Parallel
} else {
TraversalDriver::Sequential
};
let traversal = RecalcStyleAndConstructFlows::new(layout_context, traversal_driver);
let dom_depth = Some(0); // This is always the root node.
let token = {
let stylist = &<RecalcStyleAndConstructFlows as
DomTraversal<ServoLayoutElement>>::shared_context(&traversal).stylist;
<RecalcStyleAndConstructFlows as
DomTraversal<ServoLayoutElement>>::pre_traverse(element, stylist, /* skip_root = */ false)
};
if token.should_traverse() {
// 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.
if traversal_driver.is_parallel() {
let pool = self.parallel_traversal.as_mut().unwrap();
// Parallel mode
parallel::traverse_dom::<ServoLayoutElement, RecalcStyleAndConstructFlows>(
&traversal, element, dom_depth, token, pool);
} else {
// Sequential mode
sequential::traverse_dom::<ServoLayoutElement, RecalcStyleAndConstructFlows>(
&traversal, element, token);
}
});
// 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());
}
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();
}
// 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.
self.perform_post_style_recalc_layout_passes(&data.reflow_info,
Some(&data.query_type),
Some(&document),
&mut rw_data,
&mut layout_context);
self.respond_to_query_if_necessary(&data.query_type,
&mut *rw_data,
&mut layout_context);
}
fn respond_to_query_if_necessary(&mut self,
query_type: &ReflowQueryType,
rw_data: &mut LayoutThreadData,
context: &mut LayoutContext) {
rw_data.pending_images =
std_mem::replace(&mut context.pending_images.lock().unwrap(), vec![]);
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 mut 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(&mut translated_point,
&client_point,
&rw_data.stacking_context_scroll_offsets);
rw_data.hit_test_response = (result.last().cloned(), update_cursor);
},
ReflowQueryType::TextIndexQuery(node, mouse_x, mouse_y) => {
let node = unsafe { ServoLayoutNode::new(&node) };
let opaque_node = node.opaque();
let client_point = Point2D::new(Au::from_px(mouse_x),
Au::from_px(mouse_y));
rw_data.text_index_response =
TextIndexResponse(rw_data.display_list
.as_ref()
.expect("Tried to hit test with no display list")
.text_index(opaque_node,
&client_point,
&rw_data.stacking_context_scroll_offsets));
},
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::NodeScrollRootIdQuery(node) => {
let node = unsafe { ServoLayoutNode::new(&node) };
rw_data.scroll_root_id_response = Some(process_node_scroll_root_id_request(node));
},
ReflowQueryType::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);
},
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) {
if opts::get().relayout_event {
println!("**** pipeline={}\tForDisplay\tSpecial\tAnimationTick", self.id);
}
let reflow_info = Reflow {
goal: ReflowGoal::ForDisplay,
page_clip_rect: max_rect(),
};
let mut layout_context = self.build_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);
let mut pending_images = layout_context.pending_images.lock().unwrap();
if pending_images.len() > 0 {
//XXXjdm we drop all the images on the floor, but there's no guarantee that
// the node references are valid since the script thread isn't paused.
// need to figure out what to do here!
pending_images.truncate(0);
}
}
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_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,
context: &mut LayoutContext) {
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), &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();
if let (true, Some(traversal)) = (self.parallel_flag, self.parallel_traversal.as_mut()) {
// Parallel mode.
LayoutThread::solve_constraints_parallel(traversal,
FlowRef::deref_mut(&mut root_flow),
profiler_metadata,
self.time_profiler_chan.clone(),
&*context);
} else {
//Sequential mode
LayoutThread::solve_constraints(FlowRef::deref_mut(&mut root_flow), &context)
}
});
}
profile(time::ProfilerCategory::LayoutStoreOverflow,
self.profiler_metadata(),
self.time_profiler_chan.clone(),
|| {
sequential::store_overflow(context,
FlowRef::deref_mut(&mut root_flow) as &mut Flow);
});
self.perform_post_main_layout_passes(data,
query_type,
document,
rw_data,
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 LayoutContext) {
// 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(),
None,
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(),
None, 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(..) | ReflowQueryType::TextIndexQuery(..) => true,
ReflowQueryType::ContentBoxQuery(_) | ReflowQueryType::ContentBoxesQuery(_) |
ReflowQueryType::NodeGeometryQuery(_) | ReflowQueryType::NodeScrollGeometryQuery(_) |
ReflowQueryType::NodeOverflowQuery(_) | ReflowQueryType::NodeScrollRootIdQuery(_) |
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);
}
}
};
}
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