The display list is an immutable data structure, so once it's created,
rasterization can be moved to a separate thread. This allows more room
for performing other tasks between processing HTML rendering tasks.
This change makes PaintingSurface, ImmutableBitmap, and GlyphRun atomic
ref-counted, as they are shared between the main and rendering threads
by being included in the display list.
With this change we maintain a data structure that maps ids to
corresponding elements. This allows us to avoid tree traversal in
getElementById() in all cases except ones when lookup happens for
unconnected elements.
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 full invalidation was just papering over earlier bugs in the
partial layout tree update code. The DOM mutations that happen here
should be enough to drive the necessary invalidation now.
Note that this is covered by a regression test added with the
invalidation.
Before this change, an element masked with 'mask-image: url(...)' would
show the mask, but 'mask: url(...)' would not. On e.g. dialogic.nl it
would show white boxes instead of the actual images in the top
navigation bar. We still do not support many of the other mask
properties, but with this change at least the masks show up in both
cases.
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 reduces the number of `.cpp` files that need to be recompiled when
one of the below header files changes as follows:
Painting/Command.h: 1030 -> 61
Painting/DisplayList.h: 1030 -> 60
Painting/DisplayListRecorder.h: 557 -> 59
This is required to store Content Security Policies, as their
Directives are implemented as subclasses with overridden virtual
functions. Thus, they cannot be stored as generic Directive classes, as
it'll lose the ability to call overridden functions when they are
copied.
Our existing coalescing mechanism for input events didn't prevent
multiple mousemove/mousewheel events from being processed between paint
cycles. Since handling these events can trigger style & layout updates
solely for hit-testing purposes, we might end up doing work that won't
be observable by a user and could be avoided by shceduling input events
processing to happen right before painting the next frame.
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.
This is the current name for this property in CSS-Text-4. We don't
implement it, but at least our "missing property" message can be about
one we haven't implemented instead of one that's redundant. :^)
Currently, this metadata is only provided on the insertion steps,
though I believe it would be useful to extend to the other cases
as well. This metadata can aid in making optimizations for these
steps by providing extra context into the type of change which
was made on the child.
To be properly compatible with calc(), the resolved() methods all need:
- A length resolution context
- To return an Optional, as the calculation might not be resolvable
A bonus of this is that we can get rid of the overloads of `resolved()`
as they now all behave the same way.
A downside is a scattering of `value_or()` wherever these are used. It
might be the case that all unresolvable calculations have been rejected
before this point, but I'm not confident, and so I'll leave it like
this for now.
We were previously crashing when invoking 'scroll to the fragment' on
such documents as it was unable to find the active document. This is
as a result of our AD-HOC implementation not setting up the document
fully to mark it is active before running the parser.
Fixes a crash on https://tweakers.net.
This is sub-optimal but let's rebuild the whole tree for now, since this
case gets quite complicated and there are more valuable things to chase
after first.
Thanks to Gingeh for the reduced test case!
We added these methods to propagate OOM errors at process startup, but
we longer fret about these tiny OOM failures. Requiring that these init
methods be called prohibits using these strings in processes that have
not set up a MainThreadVM. So let's just remove them and initialize the
strings in a sane manner.
In doing so, this also standardizes how we initialize strings whose C++
variable name differs from their string value. Instead of special-casing
these strings, we just include their string value in the x-macro list.
This change adds computation of ARIA roles for a number of SVG elements
for which, if the element meets the SVG spec criteria for inclusion in
the accessibility tree, the computed ARIA role should be
“graphics-symbol”, and should otherwise be “generic”.
This change also adds similar role computation for the SVG foreignObject
element (the role for which, if the element meets the SVG spec criteria
for inclusion in the accessibility tree, should be “group”, and should
otherwise be “generic”).
Many times, attribute mutation doesn't necessitate a full style
invalidation on the element. However, the conditions are pretty
elaborate, so this first version has a lot of false positives.
We only need to invalidate style when any of these things apply:
1. The change may affect the match state of a selector somewhere.
2. The change may affect presentational hints applied to the element.
For (1) in this first version, we have a fixed list of attribute names
that may affect selectors. We also collect all names referenced by
attribute selectors anywhere in the document.
For (2), we add a new Element::is_presentational_hint() virtual that
tells us whether a given attribute name is a presentational hint.
This drastically reduces style work on many websites. As an example,
https://cnn.com/ is once again browseable.
Before this change, StyleComputer would essentially take a DOM element,
find all the CSS rules that apply to it, and resolve the computed value
for each CSS property for that element.
This worked great, but it meant we had to do all the work of selector
matching and cascading every time.
To enable new optimizations, this change introduces a break in the
middle of this process where we've produced a "CascadedProperties".
This object contains the result of the cascade, before we've begun
turning cascaded values into computed values.
The cascaded properties are now stored with each element, which will
later allow us to do partial updates without re-running the full
StyleComputer machine. This will be particularly valuable for
re-implementing CSS inheritance, which is extremely heavy today.
Note that CSS animations and CSS transitions operate entirely on the
computed values, even though the cascade order would have you believe
they happen earlier. I'm not confident we have the right architecture
for this, but that's a separate issue.
