This enum type used to contain the result of parsing
one CSS source declaration (`name: value;`) and expanding shorthands.
Enum types are as big as the biggest of their variant (plus discriminant),
which was quite big because some shorthands
expand to many longhand properties.
This type was returned through many functions and methods,
wrapped and rewrapped in `Result` with different error types.
This presumably caused significant `memmove` traffic.
Instead, we now allocate an `ArrayVec` on the stack
and pass `&mut` references to it for various functions to push into it.
This type is also very big, but we never move it.
We still use an intermediate data structure because we sometimes decide
after shorthand expansion that a declaration is invalid after all
and that we’re gonna drop it.
Only later do we push to a `PropertyDeclarationBlock`,
with an entire `ArrayVec` or nothing.
In future work we can try to avoid a large stack-allocated array,
and instead writing directly to the heap allocation
of the `Vec` inside `PropertyDeclarationBlock`.
However this is tricky:
we need to preserve this "all or nothing" aspect
of parsing one source declaration,
and at the same time we want to make it as little error-prone as possible
for the various call sites.
`PropertyDeclarationBlock` curently does property deduplication
incrementally: as each `PropertyDeclaration` is pushed,
we check if an existing declaration of the same property exists
and if so overwrite it.
To get rid of the stack allocated array we’d need to somehow
deduplicate separately after pushing multiple `PropertyDeclaration`.
We need another flag that represents allow-negative-number for SMIL, so
this enum will also comprise the another parsing mode that allows negative number.
Styling was correct because of the explicit dirtiness, but still not fun.
Some things, like dynamic updates to with things like [style~="color"] ~ foo
selectors, were pretty broken, because we didn't take snapshots of those
attributes.
* `LonghandId` and `ShorthandId` are C-like enums
* `Atom` is used for the name of custom properties.
* `PropertyDeclarationId` is the identifier for `PropertyDeclaration`,
after parsing and shorthand expansion. (Longhand or custom property.)
* `PropertyId` represents any CSS property, e.g. in CSSOM.
(Longhand, shorthand, or custom.)
Using these instead of strings avoids some memory allocations and copies.
Add lots of Arc’s in style, and prepare for using DOMRefCell
<!-- Please describe your changes on the following line: -->
`DOMRefCell` usage is not there year because of thread-safety questions, but I have this much already that I’d like to land before it bitrots.
r? @emilio
---
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- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [ ] These changes fix #__ (github issue number if applicable).
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- [ ] There are tests for these changes OR
- [x] These changes do not require new tests because refactor
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This reverts commit 1637b0ba8a.
* As far as I know, `fn` pointers don’t necessarily inline well
* Upcoming commits are gonna change this mapping to be less trivial,
so this would at least need a new `fn` declaration, making this
less of a simplification.
csstext
- [x] These changes fix#4431.
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy --faster` reports one error for the `css_properties_accessors!` macro not having a spec link
```
$ git log -1 --format=oneline
91fb9bf1d3 fixup! implement cssText
$ ./mach build -d
Compiling style v0.0.1 (file:///Users/greg/servo/components/style)
Compiling gfx v0.0.1 (file:///Users/greg/servo/components/gfx)
Compiling script v0.0.1 (file:///Users/greg/servo/components/script)
Compiling layout_traits v0.0.1 (file:///Users/greg/servo/components/layout_traits)
Compiling compositing v0.0.1 (file:///Users/greg/servo/components/compositing)
Compiling glutin_app v0.0.1 (file:///Users/greg/servo/ports/glutin)
Compiling constellation v0.0.1 (file:///Users/greg/servo/components/constellation)
Compiling layout v0.0.1 (file:///Users/greg/servo/components/layout)
Compiling servo v0.0.1 (file:///Users/greg/servo/components/servo)
Build completed in 0:05:11.475584
$ ./mach test-tidy --faster
Checking files for tidiness...
./components/script/dom/cssstyledeclaration.rs:386: method declared in webidl is missing a comment with a specification link
Progress: 100% (12/12)
```
- [x] There are tests for these changes. More CSSOM tests pass, but others fail that probably shouldn't:
* `./mach test-css tests/wpt/css-tests/cssom-1_dev/html/index-002.htm` and a bunch of the other tests in `/css-tests/cssom-1_dev/html/ crash when run individually
* `./mach test-css tests/wpt/css-tests/cssom-1_dev/html/cssom-cssText-serialize.htm` fails to strip a trailing semicolon (`left: 10px` vs `left: 10px;`)
* `./mach test-css tests/wpt/css-tests/cssom-1_dev/html/index-001.htm` shared shorthand values aren't coalesced (`margin: 20px` vs. `margin: 20px 20px 20px 20px`)
* `./mach test-css tests/wpt/css-tests/cssom-1_dev/html/cssstyledeclaration-csstext.htm` also crashes and fails for `color: red;` vs. `color: RED;`, preserving declaration insertion order, whitespace in the value, and setting an unknown style property.
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