While right now this doesn't save much complexity, it will do once we
care about multiple background layers per node. Then, having a single
repeat value per layer will simplify things.
It also means we can remove the pseudo-property concept entirely! :^)
Use a simple heuristic to exclude uninteresting whitespace and
de-clutter the inspector's DOM tree.
Uninteresting whitespace is currently one of these:
- Non-rendered whitespace-only text nodes
- Rendered whitespace-only text nodes between block-level elements
This changes Web::Bindings::throw_dom_exception_if_needed() to return a
JS::ThrowCompletionOr instead of an Optional. This allows callers to
wrap the invocation with a TRY() macro instead of making a follow-up
call to should_return_empty(). Further, this removes all invocations to
vm.exception() in the generated bindings.
This allows supporting websites to use a light or dark theme to match
our desktop theme, without being limited to palette colors. This can be
overridden with the `WebContentServer::set_preferred_color_scheme()` IPC
call.
Rather than following the spec exactly and creating lowercase strings,
we can simply do a case-insensitive string comparison. The caveat is
that creating attributes must follow the spec by creating the attribute
name with a lowercase string.
This is similar to how Gecko avoids a reference cycle, where both the
NamedNodeMap and Attribute would otherwise store a strong reference to
their associated Element. Gecko manually clears stored raw references
when an Element is destroyed, whereas we use weak references to do so
automatically.
Attribute's ownerElement getter and setter are moved out of line to
avoid an #include cycle between Element and Attribute.
Note our Attribute class is what the spec refers to as just "Attr". The
main differences between the existing implementation and the spec are
just that the spec defines more fields.
Attributes can contain namespace URIs and prefixes. However, note that
these are not parsed in HTML documents unless the document content-type
is XML. So for now, these are initialized to null. Web pages are able to
set the namespace via JavaScript (setAttributeNS), so these fields may
be filled in when the corresponding APIs are implemented.
The main change to be aware of is that an attribute is a node. This has
implications on how attributes are stored in the Element class. Nodes
are non-copyable and non-movable because these constructors are deleted
by the EventTarget base class. This means attributes cannot be stored in
a Vector or HashMap as these containers assume copyability / movability.
So for now, the Vector holding attributes is changed to hold RefPtrs to
attributes instead. This might change when attribute storage is
implemented according to the spec (by way of NamedNodeMap).
I originally implemented this as something to use the new sequence
wrapper, however, after having a look at uses with grep.app, it's used
often, for example:
- Bootstrap 5 Dropdowns
- Polymer
- Angular
- Closure
Since style update is driven by Document, moving a node with dirty style
from one document to another means that we have to schedule a style
update in the new document.
If we had a scheduled update of either of these kind, make sure to
cancel it after performing an update. Otherwise we might do a redundant
second update with the same results.
This could happen if something schedules an async layout, and before it
can happen, something requires a sync layout, which we do right away.
A types which have special functions declared with "= default can be
trivially copied. Besides being good practice, the compiler might be
able generate copy and initialize code in a more optimized way.
Found By PVS-Studio: https://pvs-studio.com/en/docs/warnings/v832/
We now evaluate the conditions of `@media` rules at the same point in
the HTML event loop as evaluation of `MediaQueryList`s. This is not
strictly to spec, but since the spec doesn't actually say when to do
this, it seems to make the most sense. In any case, it works! :^)
The recursive style update function was written a bit strangely and
would only mark descendants of the style update root as not needing a
style update.
With this patch, all nodes in the subtree now have clean style after a
style update finishes.
Layout depends on style (and not the other way around), so if the
document has dirty style when we enter update_layout(), make sure we
call update_style() before proceeding with the layout work.
This has the pleasant effect of coalescing some redundant layouts.
'static' for a function means that the symbol shall not be made public
for the result of the current compilation unit. This does not make sense
in a header, especially not if it's a large function that is used in
more than one place and not that performance-sensitive.
There's a subtle difference here. A "block box" in the spec is a
block-level box, while a "block container" is a box whose children are
either all inline-level boxes in an IFC, or all block-level boxes
participating in a BFC.
Notably, an "inline-block" box is a "block container" but not a "block
box" since it is itself inline-level.
Until now, we've internally thought of the CSS "display" property as a
single-value property. In practice, "display" is a much more complex
property that comes in a number of configurations.
The most interesting one is the two-part format that describes the
outside and inside behavior of a box. Switching our own internal
representation towards this model will allow for much cleaner
abstractions around layout and the various formatting contexts.
Note that we don't *parse* two-part "display" yet, this is only about
changing the internal representation of the property.
Spec: https://drafts.csswg.org/css-display
Instead of doing layout synchronously whenever something changes,
we now use a basic event loop timer to defer and coalesce relayouts.
If you did something that requires a relayout of the page, make sure
to call Document::set_needs_layout() and it will get coalesced with all
the other layout updates.
There's lots of room for improvement here, but this already makes many
web pages significantly snappier. :^)
Also, note that this exposes a number of layout bugs where we have been
relying on multiple relayouts to calculate the correct dimensions for
things. Now that we only do a single layout in many cases, these kind of
problems are much more noticeable. That should also make them easier to
figure out and fix. :^)
This method provides the needed information to evaluate media queries.
Every feature in Media Queries Level 4 is present, either as code or as
a FIXME: https://www.w3.org/TR/mediaqueries-4/#media-descriptor-table
There's a draft Level 5 which I have ignored for now.
Some are unimplemented for now since we do not have access to the
requested information. Some require StyleValue types that we do not yet
support. Many are hard-coded for now since we do not (and may never)
support monochrome or text-only displays for Browser.
We now invoke DOM timer callbacks via HTML tasks. This brings callback
sequencing closer to the spec, although there are still many
imperfections in this area.
