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script: Remove note_rendering_opportunity and rendering_opportunity (#34575)

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A rendering opportunity is now unconditionally triggered by handling IPC
messages in the `ScriptThread`, unless animations are running in which
case it's driven by the compositor. We can now remove calls to
`note_rendering_opportunity` and `rendering_opportunity`.

There is one tricky case, which is when a promise completion during a
microtask checkpoint dirties the page again. In this case we need to
trigger a new rendering opportunity, unless animations are running.  In
a followup change, when not driven by the compositor, rendering
opportunities will be driven by a timed task, meaning we can remove this
workaround.

Signed-off-by: Martin Robinson <mrobinson@igalia.com>
This commit is contained in:
Martin Robinson 2024-12-12 09:43:58 +01:00 • committed by GitHub
parent 7fcde1f7a3
commit 2bcee38e52
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6 changed files with 63 additions and 66 deletions
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95
components/script/script_thread.rs
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@ -457,9 +457,6 @@ unsafe_no_jsmanaged_fields!(TaskQueue<MainThreadScriptMsg>);
pub struct ScriptThread {
/// <https://html.spec.whatwg.org/multipage/#last-render-opportunity-time>
last_render_opportunity_time: DomRefCell<Option<Instant>>,
/// Used to batch rendering opportunities
#[no_trace]
update_the_rendering_task_queued_for_pipeline: DomRefCell<HashSet<PipelineId>>,
/// The documents for pipelines managed by this thread
documents: DomRefCell<DocumentCollection>,
/// The window proxies known by this thread
@ -806,12 +803,6 @@ impl ScriptThreadFactory for ScriptThread {
}
impl ScriptThread {
pub fn note_rendering_opportunity(pipeline_id: PipelineId) {
with_script_thread(|script_thread| {
script_thread.rendering_opportunity(pipeline_id);
})
}
pub fn runtime_handle() -> ParentRuntime {
with_optional_script_thread(|script_thread| {
script_thread.unwrap().js_runtime.prepare_for_new_child()
@ -1200,7 +1191,6 @@ impl ScriptThread {
ScriptThread {
documents: DomRefCell::new(DocumentCollection::default()),
last_render_opportunity_time: Default::default(),
update_the_rendering_task_queued_for_pipeline: Default::default(),
window_proxies: DomRefCell::new(HashMapTracedValues::new()),
incomplete_loads: DomRefCell::new(vec![]),
incomplete_parser_contexts: IncompleteParserContexts(RefCell::new(vec![])),
@ -1509,9 +1499,7 @@ impl ScriptThread {
/// Attempt to update the rendering and then do a microtask checkpoint if rendering was actually
/// updated.
pub(crate) fn update_the_rendering(&self, requested_by_compositor: bool, can_gc: CanGc) {
self.update_the_rendering_task_queued_for_pipeline
.borrow_mut()
.clear();
*self.last_render_opportunity_time.borrow_mut() = Some(Instant::now());
if !self.can_continue_running_inner() {
return;
@ -1560,11 +1548,11 @@ impl ScriptThread {
// Note: the spec reads: "for doc in docs" at each step
// whereas this runs all steps per doc in docs.
for pipeline_id in documents_in_order {
for pipeline_id in documents_in_order.iter() {
let document = self
.documents
.borrow()
.find_document(pipeline_id)
.find_document(*pipeline_id)
.expect("Got pipeline for Document not managed by this ScriptThread.");
// TODO(#31581): The steps in the "Revealing the document" section need to be implemente
@ -1573,7 +1561,7 @@ impl ScriptThread {
// TODO: Should this be broken and to match the specification more closely? For instance see
// https://html.spec.whatwg.org/multipage/#flush-autofocus-candidates.
self.process_pending_compositor_events(pipeline_id, can_gc);
self.process_pending_compositor_events(*pipeline_id, can_gc);
// TODO(#31665): Implement the "run the scroll steps" from
// https://drafts.csswg.org/cssom-view/#document-run-the-scroll-steps.
@ -1644,48 +1632,50 @@ impl ScriptThread {
// https://drafts.csswg.org/css-position-4/#process-top-layer-removals.
}
// Perform a microtask checkpoint as the specifications says that *update the rendering* should be
// run in a task and a microtask checkpoint is always done when running tasks.
// Perform a microtask checkpoint as the specifications says that *update the rendering*
// should be run in a task and a microtask checkpoint is always done when running tasks.
self.perform_a_microtask_checkpoint(can_gc);
// If there are pending reflows, they were probably caused by the execution of
// the microtask checkpoint above and we should spin the event loop one more
// time to resolve them.
self.schedule_rendering_opportunity_if_necessary();
}
/// <https://html.spec.whatwg.org/multipage/#event-loop-processing-model:rendering-opportunity>
fn rendering_opportunity(&self, pipeline_id: PipelineId) {
*self.last_render_opportunity_time.borrow_mut() = Some(Instant::now());
// Note: the pipeline should be a navigable with a rendering opportunity,
// and we should use this opportunity to queue one task for each navigable with
// an opportunity in this script-thread.
let Some(document) = self.documents.borrow().find_document(pipeline_id) else {
warn!("Trying to update the rendering for closed pipeline {pipeline_id}.");
return;
};
let window = document.window();
let task_manager = window.task_manager();
let rendering_task_source = task_manager.rendering_task_source();
let canceller = task_manager.task_canceller(TaskSourceName::Rendering);
if !self
.update_the_rendering_task_queued_for_pipeline
.borrow_mut()
.insert(pipeline_id)
{
// If there are any pending reflows and we are not having rendering opportunities
// driven by the compositor, then schedule the next rendering opportunity.
//
// TODO: This is a workaround until rendering opportunities can be triggered from a
// timer in the script thread.
fn schedule_rendering_opportunity_if_necessary(&self) {
// If any Document has active animations of rAFs, then we should be receiving
// regular rendering opportunities from the compositor (or fake animation frame
// ticks). In this case, don't schedule an opportunity, just wait for the next
// one.
if self.documents.borrow().iter().any(|(_, document)| {
document.animations().running_animation_count() != 0 ||
document.has_active_request_animation_frame_callbacks()
}) {
return;
}
let Some((_, document)) = self.documents.borrow().iter().find(|(_, document)| {
!document.window().reflows_suppressed() && document.needs_reflow().is_some()
}) else {
return;
};
// Queues a task to update the rendering.
// <https://html.spec.whatwg.org/multipage/#event-loop-processing-model:queue-a-global-task>
//
// Note: The specification says to queue a task using the navigable's active
// window, but then updates the rendering for all documents.
let _ = rendering_task_source.queue_with_canceller(
task!(update_the_rendering: move || {
// This task is empty because any new IPC messages in the ScriptThread trigger a
// rendering update, unless animations are running, in which case updates are driven
// by the compositor.
}),
&canceller,
);
//
// This task is empty because any new IPC messages in the ScriptThread trigger a
// rendering update when animations are not running.
let rendering_task_source = document.window().task_manager().rendering_task_source();
let _ =
rendering_task_source.queue_unconditionally(task!(update_the_rendering: move || { }));
}
/// Handle incoming messages from other tasks and the task queue.
@ -1932,9 +1922,6 @@ impl ScriptThread {
for document in docs.iter() {
let _realm = enter_realm(&**document);
document.maybe_queue_document_completion();
// Document load is a rendering opportunity.
ScriptThread::note_rendering_opportunity(document.window().pipeline_id());
}
docs.clear();
}
@ -2847,7 +2834,6 @@ impl ScriptThread {
self.profile_event(ScriptThreadEventCategory::Resize, Some(id), || {
let window = self.documents.borrow().find_window(id);
if let Some(ref window) = window {
self.rendering_opportunity(id);
window.add_resize_event(size, size_type);
return;
}
@ -3390,12 +3376,6 @@ impl ScriptThread {
// TODO: This should only dirty nodes that are waiting for a web font to finish loading!
document.dirty_all_nodes();
// This is required because the handlers added to the promise exposed at
// `document.fonts.ready` are run by the event loop only when it performs a microtask
// checkpoint. Without the call below, this never happens and the promise is 'stuck' waiting
// to be resolved until another event forces a microtask checkpoint.
self.rendering_opportunity(pipeline_id);
}
/// Handles a worklet being loaded by triggering a relayout of the page. Does nothing if the
@ -3872,7 +3852,6 @@ impl ScriptThread {
warn!("Compositor event sent to closed pipeline {pipeline_id}.");
return;
};
self.rendering_opportunity(pipeline_id);
document.note_pending_compositor_event(event);
}