By modeling it as a separate layer that behaves somewhat specially.
See https://github.com/w3c/csswg-drafts/issues/6872.
The remaining revert-layer tests that we fail are because either we
don't implement a feature (like @property) or because it's used in
keyframes (where revert is a bit unspecified and we have existing
issues with it).
Differential Revision: https://phabricator.services.mozilla.com/D133373
This patch looks bigger than it is, but it's mostly because
of plumbing.
To implement revert-layer we need not only the cascade origin of the
declaration, but the whole cascade level, plus also the layer order.
In order to do this, encapsulate these two things inside a 32-bit
`CascadePriority` struct and plumb it through the rule tree and so on.
This allows us to remove the packing and unpacking of CascadeLevel,
though I kept the ShadowCascadeOrder limit for now in case we need to
reintroduce it.
Fix `!important` behavior of layers while at it (implementing it in
`CascadeLevel::cmp`, spec quote included since it was tricky to find)
since some revert-layer tests were depending on it.
The style attribute test is failing now, but follow-up commit fixes
it, see spec issue.
In terms of the actual keyword implementation, it's sort of
straight-forward: We implement revert and revert-layer in a shared
way, by storing the cascade priority that reverted it.
Differential Revision: https://phabricator.services.mozilla.com/D133372
This patch computes the author-specified properties during the CSS cascade, and
removes the complex rule-tree-based implementation that tries to do the cascade
again.
This changes behavior in two ways, one of them which is not observable to
content, I believe:
* revert now re-enables the native styling. This was brought up in
https://github.com/w3c/csswg-drafts/issues/4777 and I think it is a bug-fix.
This is observable to content, and I'm adding a test for it.
* We don't look at inherited styles from our ancestors when `inherit` is
specified in a non-author stylesheet. This was introduced for bug 452969 but
we don't seem to inherit background anymore for file controls or such. It
seems back then file controls used to have a text-field.
I audited forms.css and ua.css and we don't explicitly inherit
padding / border / background-color into any nested form control.
We keep the distinction between border/background and padding, because the later
has some callers. I think we should try to align with Chromium in the long run
and remove the padding bit.
We need to give an appearance to the range-thumb and such so that we can assert
that we don't call HasAuthorSpecifiedRules on non-themed stuff. I used a new
internal value for that.
Differential Revision: https://phabricator.services.mozilla.com/D67722
This patch computes the author-specified properties during the CSS cascade, and
removes the complex rule-tree-based implementation that tries to do the cascade
again.
This changes behavior in two ways, one of them which is not observable to
content, I believe:
* revert now re-enables the native styling. This was brought up in
https://github.com/w3c/csswg-drafts/issues/4777 and I think it is a bug-fix.
This is observable to content, and I'm adding a test for it.
* We don't look at inherited styles from our ancestors when `inherit` is
specified in a non-author stylesheet. This was introduced for bug 452969 but
we don't seem to inherit background anymore for file controls or such. It
seems back then file controls used to have a text-field.
I audited forms.css and ua.css and we don't explicitly inherit
padding / border / background-color into any nested form control.
We keep the distinction between border/background and padding, because the later
has some callers. I think we should try to align with Chromium in the long run
and remove the padding bit.
We need to give an appearance to the range-thumb and such so that we can assert
that we don't call HasAuthorSpecifiedRules on non-themed stuff. I used a new
internal value for that.
Differential Revision: https://phabricator.services.mozilla.com/D67722
This assert was wrong. The assert may fire if we resurrect the node from a
different thread and insert a kid fast enough.
We allow resurrecting nodes (bumping the nodes from zero to one) to avoid
allocation churn.
In particular, while the thread dropping the node gets to read the children (so
after the fetch_sub from the refcount, but before the read() of the children),
another thread could plausibly bumped the refcount back, and added a children.
This is a very big edge case of course, but I'm kinda sad I hadn't realized
before.
Differential Revision: https://phabricator.services.mozilla.com/D63286
There were two issues with the existing code that we use to determine whether a
widget is styled or not.
First, it was using `color == Color::transparent()` instead of
`color.is_transparent()` to check for transparent backgrounds. That is not sound
as `Color::transparent()` is the literal value `rgba(0, 0, 0, 0)`, not the
`transparent` keyword, so the equality check would fail.
The other issue is that this function was early-returning false if that check
was returning false. It is a bug for this function to early-return false, as it
makes the result of the function dependent of the order of the declarations.
Differential Revision: https://phabricator.services.mozilla.com/D62060
This needs https://github.com/eqrion/cbindgen/pull/362, but I expect it to be
uncontroversial. I'll add a patch to this bug when it's merged to update it.
cbindgen historically didn't include these, but it turns out to be pretty useful
to generate constants for the style crate (since the binding crate is
`servo/ports/geckolib`).
An alternative is to get a completely different cbindgen-generated header for
these, but that seems a bit wasteful. This generates the constants with the
Style prefix (so we'll get `StyleMAX_GRID_LINE` for example), which is very
ugly. But we probably want to eventually stop using the Style prefix and use a
namespace instead, plus it's trivial to do `auto kMaxLine = StyleMAX_GRID_LINE`,
for example, so it's probably not a huge deal.
Another alternative would be to use associated consts, which _are_ generated by
cbindgen. Something like:
```
struct GridConstants([u8; 0]);
impl GridConstants {
const MAX_GRID_LINE: i32 = 10000;
}
```
Which would yield something like:
```
static const int32 StyleGridConstants_MAX_GRID_LINE = 10000;
```
I'm not sure if you find it preferrable, but I'm also happy to change it in a
follow-up to use this.
We need to fix a few manual C++ function signature definitions to match the C++
declaration.
Differential Revision: https://phabricator.services.mozilla.com/D35197
This needs https://github.com/eqrion/cbindgen/pull/362, but I expect it to be
uncontroversial. I'll add a patch to this bug when it's merged to update it.
cbindgen historically didn't include these, but it turns out to be pretty useful
to generate constants for the style crate (since the binding crate is
`servo/ports/geckolib`).
An alternative is to get a completely different cbindgen-generated header for
these, but that seems a bit wasteful. This generates the constants with the
Style prefix (so we'll get `StyleMAX_GRID_LINE` for example), which is very
ugly. But we probably want to eventually stop using the Style prefix and use a
namespace instead, plus it's trivial to do `auto kMaxLine = StyleMAX_GRID_LINE`,
for example, so it's probably not a huge deal.
Another alternative would be to use associated consts, which _are_ generated by
cbindgen. Something like:
```
struct GridConstants([u8; 0]);
impl GridConstants {
const MAX_GRID_LINE: i32 = 10000;
}
```
Which would yield something like:
```
static const int32 StyleGridConstants_MAX_GRID_LINE = 10000;
```
I'm not sure if you find it preferrable, but I'm also happy to change it in a
follow-up to use this.
We need to fix a few manual C++ function signature definitions to match the C++
declaration.
Differential Revision: https://phabricator.services.mozilla.com/D35197
I need to profile this a bit more, but talos was pretty happy about this, and it
solves the known performance issues here such as the test-case from bug 1483963
for example. This also gets rid of a bunch of unsafe code which is nice.
This still keeps the same GC scheme, removing the key from the hashmap when
needed. I kept those as release assertions, but should probably be turned into
debug-only assertions.
Differential Revision: https://phabricator.services.mozilla.com/D6801
We cannot compile with just feature(gecko + debug_assertions), since that's how
debug rusttests get compiled and they don't have the refcount logging stuff.
We were getting away with it for the pre-existing usage of the style crate,
because it wasn't used during any test and presumably the linker didn't
complain. But servo_arc is definitely used in tests.
Differential Revision: https://phabricator.services.mozilla.com/D32691
The only fishy bit is the animation stuff. In particular, there are two places
where we just mint the revert behavior:
* When serializing web-animations keyframes (the custom properties stuff in
declaration_block.rs). That codepath is already not sound and I wanted to
get rid of it in bug 1501530, but what do I know.
* When getting an animation value from a property declaration. At that point
we no longer have the CSS rules that apply to the element to compute the
right revert value handy. It'd also use the wrong style anyway, I think,
given the way StyleBuilder::for_animation works.
We _could_ probably get them out of somewhere, but it seems like a whole lot
of code reinventing the wheel which is probably not useful, and that Blink
and WebKit just cannot implement either since they don't have a rule tree,
so it just doesn't seem worth the churn.
The custom properties code looks a bit different in order to minimize hash
lookups in the common case. FWIW, `revert` for custom properties doesn't seem
very useful either, but oh well.
Differential Revision: https://phabricator.services.mozilla.com/D21877
Without this change an assertion checking IsInStyleRefresh() in
EffectCompositor::PostRestyleForAnimation will be hit when we call
FindAnimationsForCompositor from RestyleManager::DoProcessPendingRestyles
that will be introduced in a subsequent commit in this series.
I wrote a crash test which causes an assertion in KeyframeEffect::CanThrottle()
without the subsequent commit, but we need more work in display item stuff to
make the assertion won't happen (bug 1508466).
Depends on D12367
Differential Revision: https://phabricator.services.mozilla.com/D12368
