Prep for rasterizing each Navigable independently, where children must
paint before their parents — the event loop needs to walk documents in
an order where every child comes after its container. The HTML spec
already mandates such an order for the "docs" list: each document
appears after its container, with siblings in shadow-including tree
order.
Maintain m_documents in that sorted order, re-sorting lazily when a
document is registered or its navigable is reassigned.
In `::spin_processing_tasks_with_source_until()`, we would first take a
set of tasks based on a filter, and then run them one by one. If there
was more than one task matched and put in that vector, they could
interfere with each other's runnability by making later tasks
permanently unrunnable.
The `::take_tasks_matching()` API is a footgun - remove it in favor of
an API that takes tasks one by one, performing the runnability check
just in time.
Avoid expensive cross-hierarchy dynamic_cast from JS::Object to
UniversalGlobalScopeMixin on every microtask checkpoint.
Since UniversalGlobalScopeMixin is not in the JS::Object
inheritance chain, as<UniversalGlobalScopeMixin>(JS::Object&)
falls through to dynamic_cast, which is very costly. Profiling
showed this taking ~14% of total CPU time.
Add EnvironmentSettingsObject::universal_global_scope() backed
by a pointer cached eagerly during initialization.
This moves normal/double/triple click checking into WebContent, the
client only has to send a click count in order to activate a double
or triple click in the content. This means that the AppKit UI will no
longer fire multiple double clicks when clicking in place more than 3
times. This matches the behavior of other browsers on macOS.
We will now also fire the click event regardless of whether a dblclick
event will follow, as the spec requires.
The microtask queue is a pure FIFO (enqueue at back, dequeue from
front) but was using a Vector, making every dequeue O(n) due to
element shifting.
Replace it with AK::Queue which has O(1) dequeue. This makes a huge
difference when processing large numbers of microtasks, e.g. during
async-heavy JavaScript workloads where each `await` generates a
microtask.
Also add a for_each() method to AK::Queue so the GC can visit the
queued tasks.
Before, we could re-enter into this method and it would clear the skip
flag once the innermost call would finish. Instead, remember what the
flag's original value was and restore that.
Layout may have been invalidated by previous rendering steps (e.g. view
transitions). Re-run layout before intersection observations since they
need up-to-date geometry.
Replace the Window::scroll_by(0, 0) call at the end of
Document::update_layout() with a dedicated
Navigable::clamp_viewport_scroll_offset() that directly clamps the
viewport scroll offset to valid bounds.
The old approach re-entered layout from within layout, since scroll_by()
would trigger another layout update. The new approach is called from the
event loop's rendering steps, after layout is complete.
As FontFaces are added or removed from a FontFaceSet, and as they load
or fail, the FontFaceSet moves them between a few different lists, and
updates its loading/loaded status. In the spec, this is how the
FontFaceSet.[[ReadyPromise]] gets fulfilled: When the document has
finished loading and FontFaceSet.[[LoadingFonts]] is empty, it resolves
the promise.
To support this, FontFace now keeps a set of FontFaceSets that it is
contained in.
This lets us remove the non-spec resolve_ready_promise() call in
EventLoop which was sometimes triggering before any fonts had attempted
to load.
As noted, there's a spec issue with the ready promise: If nothing
modifies the document's fonts, then it would never resolve. My ad-hoc
fix is to also switch the FontFaceSet to the loaded state if it is
empty, which appears to solve the issues but is not ideal.
present() now snapshots the PaintingSurface into an ImmutableBitmap
and publishes it to the ExternalContentSource, so the rendering thread
never touches the live GPU surface — eliminating the data race
described in the ExternalContentSource commit (problem 1).
Canvas elements are registered with Page and presented once per frame
from the event loop, rather than on every individual draw call in
CRC2D::did_draw(). A dirty flag on HTMLCanvasElement ensures the
snapshot is only taken when content has actually changed, and makes
the present() call in CanvasPaintable::paint() a no-op when the
surface has already been snapshotted for the current frame.
The HTML event loop spec explicitly provides guidance for reentrancy in
the "perform a microtask checkpoint" algorithm, so we cannot VERIFY
for empty execution context before this early exit (as much as we'd
like to).
https://html.spec.whatwg.org/multipage/webappapis.html#perform-a-microtask-checkpoint
See the microtask-checkpoint-reentrancy-via-responsexml-script test for
an example of how this can happen from user scripts.
Dispatching scroll events could cause new scroll events to get lined up
and added to `m_pending_scroll_events`. The spec then asks us to empty
out that list, removing those newly added events.
Prevent doing that by emptying out the list before iterating over the
events. Fixes part of the WPT test `html/webappapis/scripting/event-
loops/new-scroll-event-dispatched-at-next-updating-rendering-time.html`.
When triple clicking on text, we should select the entire paragraph, or
entire line in <input>s and <textarea>s. If the mouse button is held
down and the user starts dragging, the selection expands with additional
paragraphs or lines.
This expands on the work of Kai Wildberger (PR #7681) but was adjusted
for the work that happened previously to support double click + drag
moves and includes triple click support for our Qt UI.
Co-authored-by: Kai Wildberger <kiawildberger@gmail.com>
Now that we don't always honor requests to add tasks to a queue, we
can't rely on "last added task" as the place to find the task's ID.
Fortunately we can just get it from the task itself.
Font computation and loading is distinct enough from style computation
that it makes more sense to have this in it's own class.
This will be useful later when we move the font loading process to
`ComputedProperties` in order to respect animated values.
With this commit, all PlaybackManager can do is autoplay a file from
start to finish, with no pausing or seeking functionality.
All audio playback functionality has been removed from HTMLMediaElement
and HTMLAudioElement in anticipation of PlaybackManager taking that
over, for both audio-only and audio/video.
Adds pinch event handling that adjusts the VisualViewport scale and
offset. VisualViewport's (offset, scale) is then used to construct a
transformation matrix which is applied before display list execution.
This also fixes a bug in the view transitions code that was
required to get the imported test to pass. The code for setting
the initial containing block size just did not set the right thing,
since doing so would trigger an error later on.
That later error resulted from walking up the tree, without
considering that the document element has a parent that is not
itself an element. (and then doing element things to it)
The faux position we created here is adjusted by the device pixel ratio
later on, which would invoke integer overflow on screens with a DPR
greater than 1.
Instead of creating special data for a mouse move event, let's just add
an explicit leave event handler.
Making navigables responsible for backing store allocation will allow us
to have separate backing stores for iframes and run paint updates for
them independently, which is a step toward isolating them into separate
processes.
Another nice side effect is that now Skia backend context is ready by
the time backing stores are allocated, so we will be able to get rid of
BackingStore class in the upcoming changes and allocate PaintingSurface
directly.
This list we are iterating over is removed from when there are
no more GC references to an ESO. This may be triggered by a GC
allocation. Since
UniversalGlobalScopeMixin::notify_about_rejected_promises performs
GC allocations (by, for example, allocating a GC function), it
is not safe to simply iterate over this list.
Fix this by taking a strong reference to all registered ESOs by
copying them across to a RootVector before iteration.
Fixes: #4652
Instead, collect a list of all the elements with content-visibility:auto
after layout.
This way we can skip the tree traversal when updating the rendering.
This was previously eating up ~300 µs of the 60fps frame budget on
our GitHub repo pages (and even more on large pages).
similar-origin window agents have the [[CanBlock]] flag set to false.
Achieve this by hooking up JS's concept with an agent to HTML::Agent.
For now, this is only hooked up to the similar-origin window agent
case but should be extended to the other agent types in the future.
Our existing coalescing mechanism for input events didn't prevent
multiple mousemove/mousewheel events from being processed between paint
cycles. Since handling these events can trigger style & layout updates
solely for hit-testing purposes, we might end up doing work that won't
be observable by a user and could be avoided by shceduling input events
processing to happen right before painting the next frame.
Before this change, `m_needs_repaint` was reset in
`Document::record_display_list()` only when the cached display list was
absent. This meant that if the last triggered repaint used the cached
display list, we would keep repainting indefinitely until the display
list was invalidated (We schedule a task that checks if repainting is
required 60/s).
This change also moves `m_needs_repaint` from Document to
TraversableNavigable as we only ever need to repaint a document that
belongs to traversable.
Previously, we were generating timestamps relative to the current time
of the monotonic clock. We now generate timestamps relative to the
event loop's last render opportunity time, per the spec.
For example, running `alert(1)` will pause the event loop, during which
time no JavaScript should execute. This patch extends this disruption to
microtasks. This avoids a crash inside the microtask executor, which
asserts the JS execution context stack is empty.
This makes us behave the same as Firefox in the following page:
<script>
queueMicrotask(() => {
console.log("inside microtask");
});
alert("hi");
</script>
Before the aforementioned assertion was added, we would execute that
microtask before showing the alert. Firefox does not do this, and now
we don't either.
This makes it more convenient to use the 'relvant agent' concept,
instead of the awkward dynamic casts we needed to do for every call
site.
mutation_observers is also changed to hold a GC::Root instead of raw
GC::Ptr. Somehow this was not causing problems before, but trips up CI
after these changes.
Instead of collecting all documents in a big vector and then filtering
the vector (twice!) with remove_all_matching(), we now pass a filter
callback to documents_in_this_event_loop_matching() and avoid all the
extra shuffling work.
Saw this stuff hogging ~20% of CPU time when profiling a WebContent
process in the middle of a WPT run.
