1. Stop using GC::Root in member variables, since that usually creates
a realm leak.
2. Stop putting OrderedHashMap<FlyString, GC::Ptr> on the stack while
setting these up, since that won't protect the objects from GC.
If there are no :defined pseudo-class selectors anywhere in the
document, we don't have to invalidate style at all when an element's
custom element state changes.
Many times, attribute mutation doesn't necessitate a full style
invalidation on the element. However, the conditions are pretty
elaborate, so this first version has a lot of false positives.
We only need to invalidate style when any of these things apply:
1. The change may affect the match state of a selector somewhere.
2. The change may affect presentational hints applied to the element.
For (1) in this first version, we have a fixed list of attribute names
that may affect selectors. We also collect all names referenced by
attribute selectors anywhere in the document.
For (2), we add a new Element::is_presentational_hint() virtual that
tells us whether a given attribute name is a presentational hint.
This drastically reduces style work on many websites. As an example,
https://cnn.com/ is once again browseable.
When the `style` attribute changes, we only need to update style on the
element itself (unless there are [style] attribute selectors somewhere).
Descendants of the element don't need a full style update, a simple
inheritance propagation is enough.
We can now mark an element as needing an "inherited style update" rather
than a full "style update". This effectively means that the next style
update will visit the element and pull all of its inherited properties
from the relevant ancestor element.
This is now used for descendants of elements with animated style.
Before this change, StyleComputer would essentially take a DOM element,
find all the CSS rules that apply to it, and resolve the computed value
for each CSS property for that element.
This worked great, but it meant we had to do all the work of selector
matching and cascading every time.
To enable new optimizations, this change introduces a break in the
middle of this process where we've produced a "CascadedProperties".
This object contains the result of the cascade, before we've begun
turning cascaded values into computed values.
The cascaded properties are now stored with each element, which will
later allow us to do partial updates without re-running the full
StyleComputer machine. This will be particularly valuable for
re-implementing CSS inheritance, which is extremely heavy today.
Note that CSS animations and CSS transitions operate entirely on the
computed values, even though the cascade order would have you believe
they happen earlier. I'm not confident we have the right architecture
for this, but that's a separate issue.
There are some special values for CSS::Selector::PseudoElement::Type
which are after `KnownPseudoElementCount` and therefore not present in
various arrays of pseudo elements, this leads to some errors, if a type
after `KnownPseudoElementCount` is used without checking first. This
adds explicit checks to all usages
This change implements full support for the “A. Hidden Not Referenced”
step at https://w3c.github.io/accname/#step2A in the “Accessible Name
and Description Computation” spec — including handling all hidden nodes
that must be ignored, as well as handling hidden nodes that, for the
purposes of accessible-name computation, must not be ignored (due to
having aria-labelledby/aria-describedby references from other nodes).
Otherwise, without this change, not all cases of hidden nodes get
ignored as expected, while cases of nodes that are hidden but that have
aria-labelledby/aria-describedby references from other nodes get
unexpectedly ignored.
Previously any existing ElementInlineCSSStyleDeclaration would get
overwritten by e.setAttribute("style", ...), while it should be updated
instead.
This fixes 2 WPT subtests.
Resulting in a massive rename across almost everywhere! Alongside the
namespace change, we now have the following names:
* JS::NonnullGCPtr -> GC::Ref
* JS::GCPtr -> GC::Ptr
* JS::HeapFunction -> GC::Function
* JS::CellImpl -> GC::Cell
* JS::Handle -> GC::Root
We currently have 2 virtual methods to inform DOM::Element subclasses
when an attribute has changed, one of which is spec-compliant. This
patch removes the non-compliant variant.
Now that the heap has no knowledge about a JavaScript realm and is
purely for managing the memory of the heap, it does not make sense
to name this function to say that it is a non-realm variant.
The main motivation behind this is to remove JS specifics of the Realm
from the implementation of the Heap.
As a side effect of this change, this is a bit nicer to read than the
previous approach, and in my opinion, also makes it a little more clear
that this method is specific to a JavaScript Realm.
Instead of doing a forced layout synchronously whenever an element's
style is changed, use a zero-timer to do the forced relayout on next
event loop iteration.
This effectively coalesces a lot of layouts and makes many pages such
as GitHub spend way less time doing redundant layout work.
The StyleResolver can find the specified CSS values for the parent
element via the DOM. Forcing everyone to locate specified values for
their parent was completely unnecessary.
Layout nodes now only carry CSS computer values with them. The main
idea here is to give them only what they need to perform layout, and
leave the rest back in the DOM.
Otherwise fetching stuff via LayoutNode::style() will have stale values
since we were only updating the specified_style() here.
LayoutNode::specified_style() should eventually go away since there's
no need to carry those uncooked values around with the layout tree.
This patch adds a simple, naive & inefficient class for document-wide
style invalidation, e.g. after element attribute updates. During
construction it collects a HashMap of a document's elements and their
matching rules, during destruction it does the same and then compares
the results; dirtying all elements that have a different number or order
of matching rules afterwards.
Much room for improvement, but it solves the problem of stale element
styling after attribute updates for now :^)
Fixes#4404.
After you mark a node as needing new style, there's no situation in
which we don't want a style update to happen, so just take care of
scheduling it automatically.
Instead of invoking the CSS parser every time we compute the style for
an element that has a "style" attribute, we now cache the result of
parsing the inline style whenever the "style" attribute is set.
This is a nice boost to relayout performance since we no longer hit the
CSS parser at all.
Bring the names of various boxes closer to spec language. This should
hopefully make things easier to understand and hack on. :^)
Some notable changes:
- LayoutNode -> Layout::Node
- LayoutBox -> Layout::Box
- LayoutBlock -> Layout::BlockBox
- LayoutReplaced -> Layout::ReplacedBox
- LayoutDocument -> Layout::InitialContainingBlockBox
- LayoutText -> Layout::TextNode
- LayoutInline -> Layout::InlineNode
Note that this is not strictly a "box tree" as we also hang inline/text
nodes in the same tree, and they don't generate boxes. (Instead, they
contribute line box fragments to their containing block!)
Reading the property has a few warts (see FIXMEs in the included
tests), but with this the timestamps on http://45.33.8.238/
get localized :^)
Since the Date() constructor currently ignores all arguments,
they don't get localized correctly but are all set to the current
time, but hey, it's still progress from a certain point of view.
You can now cycle through focusable elements (currently only hyperlinks
are focusable) with the Tab key.
The focus outline is rendered in a new FocusOutline paint phase.
HTMLElement is the only interface that includes ElementContentEditable
in the HTML specification. This makes sense, as Element is also a base
class for elements in other specifications such as SVG,
which definitely shouldn't be editable.
Also adds a test for the attribute based on what Andreas did in the
video that added it.
LibWeb keeps growing and the Web namespace is filling up fast.
Let's put DOM stuff into Web::DOM, just like we already started doing
with SVG stuff in Web::SVG.
