Previously, we would just assign the UnresolvedStyleValue to each
longhand, which was completely wrong but happened to work if it was a
ShorthandStyleValue (because that's basically a list of "set property X
to Y", and doesn't care which property it's the value of).
For example, the included `var-in-margin-shorthand.html` test would:
1. Set `margin-top` to `var(--a) 10px`
2. Resolve it to `margin-top: 5px 10px`
3. Reject that as invalid
What now happens is:
1. Set `margin-top` to a PendingSubstitutionValue
2. Resolve `margin` to `5px 10px`
3. Expand that out into its longhands
4. `margin-top` is `5px` 🎉
In order to support this, `for_each_property_expanding_shorthands()` now
runs the callback for the shorthand too if it's an unresolved or
pending-substitution value. This is so that we can store those in the
CascadedProperties until they can be resolved - otherwise, by the time
we want to resolve them, we don't have them any more.
`cascade_declarations()` has an unfortunate hack: it tracks, for each
declaration, which properties have already been given values, so that
it can avoid overwriting an actual value with a pending one. This is
necessary because of the unfortunate way that CSSStyleProperties holds
expanded longhands, and not just the original declarations. The spec
disagrees with itself about this, but we do need to do that expansion
for `element.style` to work correctly. This HashTable is unfortunate
but it does solve the problem until a better solution can be found.
We already have fast path for built-in iterators that skips `next()`
lookup and iteration result object allocation applied for `for..of` and
`for..in` loops. This change extends it to `iterator_step()` to cover
`Array.from()`, `[...arr]` and many other cases.
Makes following function go 2.35x faster on my computer:
```js
(function f() {
let arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
for (let i = 0; i < 1000000; i++) {
let [a, ...rest] = arr;
}
})();
```
Before this change, we were going through the chain of base classes for
each IDL interface object and having them set the prototype to their
prototype.
Instead of doing that, reorder things so that we set the right prototype
immediately in Foo::initialize(), and then don't bother in all the base
class overrides.
This knocks off a ~1% profile item on Speedometer 3.
"Functional" as in "it's a function token" and not "it works", because
the behaviour for these is unimplemented. :^)
This is modeled after the pseudo-class parsing, but with some changes
based on things I don't like about that implementation. I've
implemented the `<pt-name-selector>` parameter used by view-transitions
for now, but nothing else.
The upcoming generated types will match those for pseudo-classes: A
PseudoElementSelector type, that then holds a PseudoElement enum
defining what it is. That enum will be at the top level in the Web::CSS
namespace.
In order to keep the diffs clearer, this commit renames and moves the
types, and then a following one will replace the handwritten enum with
a generated one.
12c6ac78e2 with fixed mistake when cache
slot is copied instead of being referenced:
```cpp
auto cache =
box.cached_intrinsic_sizes().min_content_height.ensure(width);
```
while it should've been:
```cpp
auto& cache =
box.cached_intrinsic_sizes().min_content_height.ensure(width);
```
This change moves intrinsic sizes cache from
LayoutState, which is local to current layout run,
to layout nodes, so it could be reused between
layout runs. This optimization is possible because
we can guarantee that these measurements will
remain unchanged unless the style of the element
or any of its descendants changes.
For now, invalidation is implemented simply by
resetting cache on whole ancestors chain once we
figured that element needs layout update.
The case when layout is invalidated by DOM's
structural changes is covered by layout tree
invalidation that drops intrinsic sizes cache
along with layout nodes.
I measured improvement on couple websites:
- Mail list on GMail 28ms -> 6ms
- GitHub large code page 47ms -> 36ms
- Discord chat history 15ms -> 8ms
(Time does not include `commit()`)
This reduces the number of `.cpp` files that need to be recompiled when
one of the below header files changes as follows:
CSS/ComputedProperties.h: 1113 -> 49
CSS/ComputedValues.h: 1120 -> 209
This is not really a context, but more of a set of parameters for
creating a Parser. So, treat it as such: Rename it to ParsingParams,
and store its values and methods directly in the Parser instead of
keeping the ParsingContext around.
This has a nice side-effect of not including DOM/Document.h everywhere
that needs a Parser.
It is possible to skip inherited style recalculation for children if
parent's recalculation does not cause any changes.
Improves performance on Github where we could avoid dozens of inherited
style calculations that do not produce any visible changes.
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.
Lazily coercing might have made sense in the past, but since hashing
and comparing requires the `PropertyKey` to be coerced, and since a
`PropertyKey` will be used to index into a hashmap 99% of the time,
which will hash the `PropertyKey` and use it in comparisons, the
extra complexity and branching produced by lazily coercing has
become more trouble than it is worth.
Remove the lazy coercions, which then also neatly allows us to
switch to a `Variant`-based implementation.
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
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.
