This is a monster patch that turns all EventTargets into GC-allocated
PlatformObjects. Their C++ wrapper classes are removed, and the LibJS
garbage collector is now responsible for their lifetimes.
There's a fair amount of hacks and band-aids in this patch, and we'll
have a lot of cleanup to do after this.
We were hanging on to element inline style, even after the style
attribute was removed. This made inline style sticky and impossible to
remove. This patch fixes that. :^)
Use the new CSS::property_affects_layout() helper to figure out if we
actually need to perform a full relayout after recomputing style.
There are three tiers of required invalidation after an element receives
new style: none, repaint only, or full relayout.
This avoids the need to rebuild the layout tree (and perform layout on
it) when trivial properties like "color" etc are changed.
Let's make it very clear that these are *computed* values, and not at
all the specified values. The specified values are currently discarded
by the CSS cascade algorithm.
Build the final custom property map right away instead of first making
a temporary pointer-only map. We also precompute the final needed
capacity for the map to avoid incremental rehashing.
getClientRects supposed to return a list of bounding DOMRect
for each box fragment of Element's layout, but most elements have
only one box fragment, so implementing it with getBoundingClientRect
is useful.
Previously we would re-run the entire CSS selector machinery for each
property resolved. Instead of doing that, we now resolve a final set of
custom property key/value pairs at the start of the cascade.
Instead of making each Layout::Node compute style for itself, we now
compute it in TreeBuilder before even calling create_layout_node().
For non-element DOM nodes, we create the style and layout tree node
in TreeBuilder. This allows us to move create_layout_node() from
DOM::Node to DOM::Element.
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).
Resolved style is a spec concept that refers to the weird mix of
computed style and used style reflected by getComputedStyle().
The purpose of this class is to produce the *computed* style for a given
element, so let's call it StyleComputer.
This also moves getElementsByTagName to ParentNode to remove the code
duplication between Document and Element. This additionally fixes a bug
where getElementsByTagName did not check if the element was a
descendant, meaning it would also include the context element if the
condition matched.
The previous implementation was about a half implementation and was
tied to Element::innerHTML. This separates it and puts it into
HTMLDocumentParser, as this is in the parsing section of the spec.
This provides a near finished HTML fragment serialisation algorithm,
bar namespaces in attributes and the `is` value.
This roughly models the "queue an element task" algorithm from the spec.
For safety, this captures a strong reference to the element, and then
bundles that with a callback into a HTML::Task (that we then queue up.)
This is three small, related changes:
1. Element::has_attribute() now returns true if the attribute exists but
has no value. (eg, `<div foo />` -> `has_attribute("foo")`)
2. SelectorEngine::matches_attribute() now makes sure there is a first
segment before comparing it, fixing a crash.
3. CSS::Parser now converts attribute names in attribute selectors to
lowercase, to match the expectations of the rest of the system.
Converting to lowercase is not always correct, depending on language,
but since we only currently support HTML, and that expects them to be
case-insensitive, it is fine for now.
