With this change, we now have ~1200 CellAllocators across both LibJS and
LibWeb in a normal WebContent instance.
This gives us a minimum heap size of 4.7 MiB in the scenario where we
only have one cell allocated per type. Of course, in practice there will
be many more of each type, so the effective overhead is quite a bit
smaller than that in practice.
I left a few types unconverted to this mechanism because I got tired of
doing this. :^)
This commit removes DeprecatedString's "null" state, and replaces all
its users with one of the following:
- A normal, empty DeprecatedString
- Optional<DeprecatedString>
Note that null states of DeprecatedFlyString/StringView/etc are *not*
affected by this commit. However, DeprecatedString::empty() is now
considered equal to a null StringView.
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 :^)
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.
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.
By deferring allocation of StaticNodeList objects until we know somebody
actually wants the MutationRecord, we avoid a *lot* of allocation work.
This shaves several seconds off of loading https://tc39.es/ecma262/
At least one other engine (WebKit) skips creating mutation records if
nobody is interested, so even if this is observable somehow, we would
at least match the behavior of a major engine.
JS::PrimitiveString::create uses `is_empty()` on DeprecatedString to
use the empty string cache on the VM. However, this also considers the
DeprecatedString null state to be empty, giving an empty string instead
of `null` for null DeprecatedStrings.
Note that as of this commit, there aren't any such throwers, and the
call site in Heap::allocate will drop exceptions on the floor. This
commit only serves to change the declaration of the overrides, make sure
they return an empty value, and to propagate OOM errors frm their base
initialize invocations.
This needs to happen before prototype/constructor intitialization can be
made lazy. Otherwise, GC could run during the C++ constructor and try to
collect the object currently being created.
DeprecatedFlyString relies heavily on DeprecatedString's StringImpl, so
let's rename it to A) match the name of DeprecatedString, B) write a new
FlyString class that is tied to String.
We have a new, improved string type coming up in AK (OOM aware, no null
state), and while it's going to use UTF-8, the name UTF8String is a
mouthful - so let's free up the String name by renaming the existing
class.
Making the old one have an annoying name will hopefully also help with
quick adoption :^)
These classes only needed Window to get at its realm. Pass a realm
directly to construct DOM and WebIDL classes.
This change importantly removes the guarantee that a Document will
always have a non-null Window object. Only Documents created by a
BrowsingContext will have a non-null Window object. Documents created by
for example, DocumentFragment, will not have a Window (soon).
This incremental commit leaves some workarounds in place to keep other
parts of the code building.
