It calls Element::get_attribute which takes a StringView. Ultimately,
this should be taking a FlyString, but to help in porting away from
DeprecatedString, just leave a FIXME for that for now.
It already delegates to a function which accepts a StringView, so there
is no advantage here in taking a FlyString. Ideally, both of these
functions should be taking a 'FlyString const&', so leave a FIXME for
that. In the meantime, this should help in porting away from
DeprecatedString.
There are an unfortunate number of DeprecatedString conversions required
here, but these should all fall away and look much more pretty again
when other places are also ported away from DeprecatedString.
Leaves only the Element IDL interface left :^)
This implements automatic slottable assignment by way of hooking into
the element attribute change steps. When the `name` attribute of a slot
or the `slot` attribute of a slottable changes, assignment is performed.
A slottable is either a DOM element or a DOM text node. They may be
assigned to slots (HTMLSlotElement) either automatically or manually.
Automatic assignment occurs by matching a slot's `name` attribute to
a slottable's `slot` attribute. Manual assignment occurs by using the
slot's (not yet implemented) `assign` API.
This commit does not perform the above assignments. It just sets up the
slottable concept via IDL and hooks the slottable mixin into the element
and text nodes.
This is similar to the run activation behavior in that elements may
define these steps themselves. HTMLSlotElement is one such element. The
existing (ad-hoc) Element::attribute_changed() method is not sufficient
there as the steps require knowledge of the attribute's old value and
its namespace, which this extension provides.
Unlike the run activation behavior, we store these steps in a list. An
element may end up defining multiple attribute change steps. For example
all DOM elements must define steps to handle the "slot" attribute, and
HTMLSlotElement must define steps to handle the "name" attribute.
This is a `<display-inside>` keyword added by the MathML spec, and has
the rough meaning of "display in the default way". It enables the
standard layout rules for each MathML element (and is ignored for
anything that isn't a MathML element).
I believe we'll need an actual MathML formatting context to do the
layout correctly, but we can at least support a couple of elements that
behave the same as HTML ones.
This should allow us to add a Element::attribute which returns an
Optional<String>. Eventually all callers should be ported to switch from
the DeprecatedString version, but in the meantime, this should allow us
to port some more IDL interfaces away from DeprecatedString.
Which for now will just call the DeprecatedString version of this
function. This is intended to be used in porting code over to using the
new String equivalent with the end goal of removing the DeprecatedString
version of this function.
This allows us to port a whole heap of IDL interfaces from
DeprecatedString to String.
Currently, every public DOM::Element method which changes an attribute
fires this handler itself. This was missed in commit 720f7ba, so any
user of that API would not fire the internal handler.
To fix this, and prevent any missing invocations in the future, invoke
the handler from from Attr::handle_attribute_changes. This method is
reached for all attribute changes, including adding/removing attributes.
This ensures the handler will always be fired, and reduces the footprint
of this ad-hoc behavior.
Note that our ad-hoc handler is not the "attribute change steps" noted
by the spec. Those are overridden only by a couple of specific elements,
e.g. HTMLSlotElement. However, we could easily make our ad-hoc handler
hook into those steps in the future.
We now have functions for parsing integers in a spec-compliant way. This
patch replaces the `to_int` call with a call to the spec-compliant
`Web::HTML::parse_integer` function.
This is intended to annotate conversions from unknown floating-point
values to CSSPixels, and make it more obvious the fp value will be
rounded to the nearest fixed-point value.
In general it is not safe to convert any arbitrary floating-point value
to CSSPixels. CSSPixels has a resolution of 0.015625, which for small
values (e.g. scale factors between 0 and 1), can produce bad results
if converted to CSSPixels then scaled back up. In the worst case values
can underflow to zero and produce incorrect results.
Instead of calling to_lowercase() on two strings for every step while
iterating over the HTMLCollection returned by getElementsByTagName(),
we now cache the lowercased tag name beforehand and reuse it.
2.4x speed-up on WebKit/PerformanceTests/DOM/DOMDivWalk.html
Stop worrying about tiny OOMs. Work towards #20449.
While going through these, I also changed the function signature in many
places where returning ThrowCompletionOr<T> is no longer necessary.
is_scroll_container() returns true for "overflow: hidden" which allows
programmable scrolling while is_scrollable() returns true only for
"overflow: scroll" and "overflow: auto" which allow scrolling only by
user interactions.
The `clip_shrink` optimization in `paint_background()` now also
correctly uses DevicePixels, instead of reducing a DevicePixel rect by
a CSSPixels amount.
This change makes tree builder omit elements with "display: contents"
from the layout tree during construction. Their child elements are
instead directly appended to the parent element in layout tree.
The main missing features are rootMargin, proper nested browsing
context support and content clip/clip-path support.
This makes images appear on some sites, such as YouTube and
howstuffworks.com.
