style: Move all origin-specific cascade data to PerOriginCascadeData
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This is a preliminary refactoring in preparation for only rebuilding cascade data for origins that have a change. https://bugzilla.mozilla.org/show_bug.cgi?id=1382925
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set_list_style_type() for gecko needs an additional argument 'Device' [1], and
making list-style-type animtable makes AnimatedProperty::update() call the
set_list_style_type(). To avoid introducing the Device argument to the setter in
servo, this patch makes simply PropertyAnimation conditional build.
(Whereas in stylo, we don't use the setter for animation, we use clone_xx()
instead.)
[1] https://hg.mozilla.org/mozilla-central/file/1d042bcb2632/servo/components/style/properties/properties.mako.rs#l2667
When display style is changed from 'none' to other in animation-only restyle
we need to resolve descendant elements' style that were in the display:none
subtree.
Three possible ways to resolve the descendant elements' style;
1) Traversing unstyled elements in animation-only restyle
We can't simply traverse unstyled elements in the animation-only restyle
since when we decided to traverse the unstyled elements we don't know yet
the elements will be initially styled or are in display:none subtree. It
will result that the new elements are styled in animation-only restyle,
it's undesirable.
2) Creating a SequentialTask and resolve the descendants' style with
ServoStyleSet::StyleNewSubtree()
We can't resolve the descendants' styles with ServoStyleSet::StyleNewSubtree()
in SequentialTask since at the moment we are still in servo traversal (i.e.
sInServoTraversal is true). That means AutoSetInServoTraversal fails
in PrepareAndTraverseSubtree().
3) Creating a SequentialTask and set restyle subtree hint and defer descendants'
restyle in a subsequent normal traversal
Note that, when we process throttled animations flush, we don't process
normal traversal so the descendants will not be traversed until normal
restyle happens but it will not be a big problem since it's really rare
that user clicks display animation element just at the right moment when
display property changes from none to other. Also, if it will be really
a problem, we should process *only* transform animations on the compositor,
it's ideally right thing to do. Display property never runs on the
compositor.
This patch takes the third approach.
The alias is left there temporarilly and will be removed completely in a later commit where
also components/style/gecko/generated/structs_{debug|release}.rs are re-generated (they still
use the old alias).
When a transition update is needed during restyling, `get_after_change_style` is
called to re-cascade without transition rules, and this style is then used for
primary styling instead of the style just computed.
`get_after_change_style` used to ignore visited styles, so this meant that if a
transition update was needed, visited styles were effectively dropped.
To fix the crash here, we pass through the existing visited styles when
re-cascading as part of `get_after_change_style`.
MozReview-Commit-ID: 4HBQAdeJ38B
I've wanted to change the threshold a couple of times, and adding in a
10-minute opt rebuild cycle is always a bit de-motivating.
I'm making this option gecko-only because it's pretty niche, and adding
support in servo would require threading it through all the options
stuff. We can add support for it there if we ever need it.
MozReview-Commit-ID: HYlJpS3usP4
Before this change, the `ComputedStyle` struct that is part of permanent style
data per element holds 2 `StrongRuleNode`s (unvisited and visited) and 2
`Arc<ComputedValues>` (unvisited and visited).
Both rule nodes and the visited values don't actually need to be here. This
patch moves these 3 to new temporary storage in `CascadeInputs` on
`CurrentElementInfo` during the match and cascade process. Rule nodes are
pushed down inside the `ComputedValues` for later access after the cascade.
(Visited values were already available there.)
The permanent style data per element now has just the `Arc<ComputedValues>` for
itself and eager pseudo-elements (plus the `RestyleHint`).
MozReview-Commit-ID: 3wq52ERMpdi
In the patch after this, the existing `ComputedStyle` type is renamed and
repurposed as temporary storage of inputs for the cascade. To make it a bit
easier to follow what code is new, this patch starts by copying `ComputedStyle`
to context.rs without changes.
MozReview-Commit-ID: 41COA5rEoz7
This commit also removes the old restyle_hints module and splits it into
multiple modules under components/style/invalidation/element/.
The basic approach is to walk down the tree using compound selectors as needed,
in order to do as little selector-matching as possible.
Bug: 1368240
MozReview-Commit-ID: 2YO8fKFygZI
Stylist accessors
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Add accessor methods for the `device` and `ruleset` fields in the `Stylist` struct.
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This slims down SharedStyleContext, in preparation for a few things.
First, I would like to eventually move the stylist to the document in Servo, in
order for it to hold the StyleSheetSet.
Also, this gets rid of a fair amount of overhead while creating it in stylo.
Fixes bug 1363245.
I've chosen this approach mainly because there's no other good way to guarantee
the model is correct than holding the snapshots alive until a style refresh.
What I tried before this (storing them in a sort of "immutable element data") is
a pain, since we call into style from the frame constructor and other content
notifications, which makes keeping track of which snapshots should be cleared an
which shouldn't an insane task.
Ideally we'd have a single entry-point for style, but that's not the case right
now, and changing that requires pretty non-trivial changes to the frame
constructor.
MozReview-Commit-ID: FF1KWZv2iBM
Signed-off-by: Emilio Cobos Álvarez <emilio@crisal.io>
1. We need to call get_after_change_style, which is the computed styles
without transition rules, while process_animations.
2. If we have after-change style, we may replace the new computed values with
after-change style, according to whether we really need to update
transitions.
3. There are some cases we don't update transitions, so we need to early
return. might_needs_transitions_update() will check it first and it
will filter out most common cases.
4. needs_transitions_update() will check each property and existing running
transitions to make sure we really don't need to update transitions.
The logic of this function is similar with that of
nsTransitionManager::DoUpdateTransitions().
MozReview-Commit-ID: 2ccdPjgrxKz
I wanted to add an environmental variable to disable the style sharing
cache for gecko, but the current pattern involves lazy_static!, which
involves an atomic operation on lookup, which is a bit hot to do each
time we try to share styles. This makes that work happen once per
process.
