Previously, any SVG geometry attribute change would mark the entire
document layout tree as dirty, triggering a full layout pass even though
only the SVG subtree was affected. This made SVG geometry animations
unnecessarily expensive.
Fix this by stopping `needs_layout_update` propagation at the SVGSVGBox
boundary and tracking dirty SVG roots separately on the Document. When
`update_layout()` finds that only SVG roots need relayout (and the
document layout root is clean), it runs SVGFormattingContext on each
dirty SVG root in a fresh LayoutState and commits the results directly,
bypassing the full document layout pass entirely.
This results in a substantial performance improvement on pages with
animated SVGs, such as https://www.cloudflare.com/,
https://www.duolingo.com/, and our GC graph explorer page.
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>
This patch introduces a cookie cache in the WebContent process to reduce
blocking IPC calls when JS accesses document.cookie. The UI process now
maintains a cookie version counter per-domain in shared memory. When JS
reads document.cookie, we check whether we have a valid cached cookie by
comparing the current shared version to the last used version. If they
match, the cached cookie is returned without IPC.
This optimization is based on Chromium's shared versioning, in which it
was observed that 87% of document.cookie accesses were redundant. See:
https://blog.chromium.org/2024/06/introducing-shared-memory-versioning-to.html
Note that this cache only supports document.cookie, not HTTP Cookie
headers. HTTP cookies are attached to requests with varying URLs and
paths. The cookies that match the document URL might not match the
request URL, which we wouldn't know from WebContent. So attaching the
cached document cookie would be incorrect.
On https://twinings.co.uk, we see approximately 600 document.cookie
requests while the page loads. This patch reduces the time spent in
the document.cookie getter from ~45ms to 2-3ms.
This new API allows tests to inspect the stacking context tree structure
which is useful for verifying that stacking context invalidation and
rebuilding work correctly.
- Add WindowManagement to PolicyControlledFeature enum
- Add screen_count() virtual method to PageClient
- Store all screen rects in WebContent::PageClient, derive both
screen_rect() and screen_count() from stored data
- Implement screen_count() overrides in SVGPageClient and PageHost
- Replace FIXME stub in Screen.cpp with spec-compliant implementation
Ensure AccumulatedVisualContext stays synchronized when CSS transform
properties change.
AccumulatedVisualContext copies transform and perspective matrices from
the paintable tree at assignment time. When CSS properties that affect
these matrices change (transform, rotate, scale, translate, perspective,
transform-origin, perspective-origin), we must rebuild the
AccumulatedVisualContext tree to reflect the new values.
This adds a rebuild_accumulated_visual_contexts flag to style
invalidation that triggers a full rebuild during the next paint.
Note: The current invalidation strategy is inefficient - it rebuilds
the entire tree even for single-element transform changes. This could
be improved by patching the AccumulatedVisualContext node in-place with
updated matrices, but only when the transform doesn't transition
from/to none (which would change the tree structure). This optimization
is left for future work.
Previously, we registered `@property` rules during parsing, and treated
them the same as `CSS.registerProperty()` calls. This is not correct
for a couple of reasons: One, the spec wants us to distinguish between
those two sources of registered custom properties, with
`CSS.registerProperty()` calls taking precedence. Two, we never removed
the registered property when its `@property` was removed from the
document.
This commit deals with this by iterating active CSSPropertyRules to find
which ones currently apply, and storing those in a cache. This cache is
invalidated whenever the Document's style is invalidated, which happens
whenever a CSSRule is added or removed from the Document.
The attached test demonstrates this now working as it should.
Documents that have never been associated with a browsing context will
never become "fully active" so we shouldn't schedule tasks in them since
they'll never run.
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.
This works by generating random values using XorShift128PlusRNG at
compute time and then caching them on the document using the relevant
random-caching-key
The implementation here is a ad-hoc, but there's no clear spec for
exactly how to handle "critical subresources" blocking rendering.
For now, this is overly conservative but fixes ugly FOUC on some
websites like https://hey.com/
Before this change, we've been maintaining various StyleComputer caches
at the document level.
This made sense for old-school documents without shadow trees, since
all the style information was document-wide anyway. However, documents
with many shadow trees ended up suffering since any time you mutated
a style sheet inside a shadow tree, *all* style caches for the entire
document would get invalidated.
This was particularly expensive on Reddit, which has tons of shadow
trees with their own style elements. Every time we'd create one of their
custom elements, we'd invalidate the document-level "rule cache" and
have to rebuild it, taking about ~60ms each time (ouch).
This commit introduces a new object called StyleScope.
Every Document and ShadowRoot has its own StyleScope. Rule caches etc
are moved from StyleComputer to StyleScope.
Rule cache invalidation now happens at StyleScope level. As an example,
rule cache rebuilds now take ~1ms on Reddit instead of ~60ms.
This is largely a mechanical change, moving things around, but there's
one key detail to be aware of: due to the :host selector, which works
across the shadow DOM boundary and reaches from inside a shadow tree out
into the light tree, there are various places where we have to check
both the shadow tree's StyleScope *and* the document-level StyleScope
in order to get all rules that may apply.
We were doing this manually within `Document::update_layout()` and
`CSSStyleProperties::get_direct_property()` but we should do it for all
callers of `Document::update_style()`
Otherwise the layout tree will still contain the top layer element(s).
Fixes Steam Events & Announcements `<dialog>` modal visually not fully
disappearing upon removal.
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)
And make it a DOM::Node, not DOM::Element. This makes everything flow
much better, such as spec texts that explicitly mention "focused area"
as the fact that we don't necessarily need to traverse a tree of
elements, since a Node can be focusable as well.
Eventually this will need to be a struct with a separate "focused area"
and "DOM anchor", but this change will make it easier to achieve that.
This reverts 0e3487b9ab.
Back when I made that change, I thought we could make our StyleValue
classes match the typed-om definitions directly. However, they have
different requirements. Typed-om types need to be mutable and GCed,
whereas StyleValues are immutable and ideally wouldn't require a JS VM.
While I was already making such a cataclysmic change, I've moved it into
the StyleValues directory, because it *not* being there has bothered me
for a long time. 😅
This allows them to keep style sheets alive while loading fonts for
them. Fixes some GC crashes seen on the WPT WOFF2 tests after
66a19b8550 stopped FetchRecord leaks from
keeping various other things alive.
According to the spec, `ResizeObserver` needs to live for as long as
it's referenced from script or has observation targets. With this change
we make sure that `ResizeObserver` is unregistered from the `Document`
when it has no target.
Fixes GC leak that caused us to keep all resize observers alive until
document they belong to is destroyed.
`ShadowRoot` register itself in Document` from constructor and
unregister itself from `finalize()`. The problem is that `finalize()`
won't be invoked for as long as `ShadowRoot` is visited by
`Document`, leading to GC leaks.
