style: Will-change should only create stacking contexts / containing blocks / etc if the property it'd change would apply

As per https://drafts.csswg.org/css-will-change/#will-change.

> If any non-initial value of a property would cause the element to
> generate a containing block for absolutely positioned elements,
> specifying that property in will-change must cause the element to
> generate a containing block for absolutely positioned elements.

But in this case the transform property wouldn't apply to the element so
there's no reason to create a stacking-context.

Differential Revision: https://phabricator.services.mozilla.com/D114121
This commit is contained in:
Oriol Brufau 2023-05-17 00:44:00 +02:00
parent 60867bbe7e
commit 1cc44bd065
6 changed files with 49 additions and 58 deletions

View file

@ -48,7 +48,6 @@ ${helpers.single_keyword(
engines="gecko servo-2013 servo-2020"
animation_value_type="discrete"
gecko_enum_prefix="StylePositionProperty"
flags="CREATES_STACKING_CONTEXT ABSPOS_CB"
spec="https://drafts.csswg.org/css-position/#position-property"
servo_restyle_damage="rebuild_and_reflow"
>
@ -330,7 +329,7 @@ ${helpers.predefined_type(
engines="gecko servo-2013 servo-2020",
extra_prefixes=transform_extra_prefixes,
animation_value_type="ComputedValue",
flags="CREATES_STACKING_CONTEXT FIXPOS_CB CAN_ANIMATE_ON_COMPOSITOR",
flags="CAN_ANIMATE_ON_COMPOSITOR",
spec="https://drafts.csswg.org/css-transforms/#propdef-transform",
servo_restyle_damage="reflow_out_of_flow",
)}
@ -342,7 +341,7 @@ ${helpers.predefined_type(
engines="gecko servo-2013",
animation_value_type="ComputedValue",
boxed=True,
flags="CREATES_STACKING_CONTEXT FIXPOS_CB CAN_ANIMATE_ON_COMPOSITOR",
flags="CAN_ANIMATE_ON_COMPOSITOR",
gecko_pref="layout.css.individual-transform.enabled",
spec="https://drafts.csswg.org/css-transforms-2/#individual-transforms",
servo_restyle_damage = "reflow_out_of_flow",
@ -355,7 +354,7 @@ ${helpers.predefined_type(
engines="gecko servo-2013",
animation_value_type="ComputedValue",
boxed=True,
flags="CREATES_STACKING_CONTEXT FIXPOS_CB CAN_ANIMATE_ON_COMPOSITOR",
flags="CAN_ANIMATE_ON_COMPOSITOR",
gecko_pref="layout.css.individual-transform.enabled",
spec="https://drafts.csswg.org/css-transforms-2/#individual-transforms",
servo_restyle_damage = "reflow_out_of_flow",
@ -368,7 +367,7 @@ ${helpers.predefined_type(
engines="gecko servo-2013",
animation_value_type="ComputedValue",
boxed=True,
flags="CREATES_STACKING_CONTEXT FIXPOS_CB CAN_ANIMATE_ON_COMPOSITOR",
flags="CAN_ANIMATE_ON_COMPOSITOR",
gecko_pref="layout.css.individual-transform.enabled",
spec="https://drafts.csswg.org/css-transforms-2/#individual-transforms",
servo_restyle_damage="reflow_out_of_flow",
@ -382,7 +381,7 @@ ${helpers.predefined_type(
engines="gecko",
animation_value_type="ComputedValue",
gecko_pref="layout.css.motion-path.enabled",
flags="CREATES_STACKING_CONTEXT FIXPOS_CB CAN_ANIMATE_ON_COMPOSITOR",
flags="CAN_ANIMATE_ON_COMPOSITOR",
spec="https://drafts.fxtf.org/motion-1/#offset-path-property",
servo_restyle_damage="reflow_out_of_flow"
)}
@ -477,7 +476,6 @@ ${helpers.single_keyword(
"auto isolate",
engines="gecko",
spec="https://drafts.fxtf.org/compositing/#isolation",
flags="CREATES_STACKING_CONTEXT",
gecko_enum_prefix="StyleIsolation",
animation_value_type="discrete",
)}
@ -530,7 +528,6 @@ ${helpers.predefined_type(
gecko_ffi_name="mChildPerspective",
spec="https://drafts.csswg.org/css-transforms/#perspective",
extra_prefixes=transform_extra_prefixes,
flags="CREATES_STACKING_CONTEXT FIXPOS_CB",
animation_value_type="AnimatedPerspective",
servo_restyle_damage = "reflow_out_of_flow",
)}
@ -574,7 +571,6 @@ ${helpers.predefined_type(
engines="gecko servo-2013 servo-2020",
spec="https://drafts.csswg.org/css-transforms-2/#transform-style-property",
extra_prefixes=transform_extra_prefixes,
flags="CREATES_STACKING_CONTEXT FIXPOS_CB",
animation_value_type="discrete",
servo_restyle_damage = "reflow_out_of_flow",
)}
@ -598,7 +594,6 @@ ${helpers.predefined_type(
"specified::Contain::empty()",
engines="gecko",
animation_value_type="none",
flags="CREATES_STACKING_CONTEXT FIXPOS_CB",
spec="https://drafts.csswg.org/css-contain/#contain-property",
)}

View file

@ -13,7 +13,7 @@ ${helpers.predefined_type(
"1.0",
engines="gecko servo-2013 servo-2020",
animation_value_type="ComputedValue",
flags="CREATES_STACKING_CONTEXT CAN_ANIMATE_ON_COMPOSITOR",
flags="CAN_ANIMATE_ON_COMPOSITOR",
spec="https://drafts.csswg.org/css-color/#transparency",
servo_restyle_damage = "reflow_out_of_flow",
)}
@ -56,7 +56,6 @@ ${helpers.predefined_type(
animation_value_type="AnimatedFilterList",
vector_animation_type="with_zero",
extra_prefixes="webkit",
flags="CREATES_STACKING_CONTEXT FIXPOS_CB",
spec="https://drafts.fxtf.org/filters/#propdef-filter",
)}
@ -71,7 +70,6 @@ ${helpers.predefined_type(
separator="Space",
animation_value_type="AnimatedFilterList",
vector_animation_type="with_zero",
flags="CREATES_STACKING_CONTEXT FIXPOS_CB",
gecko_pref="layout.css.backdrop-filter.enabled",
spec="https://drafts.fxtf.org/filter-effects-2/#propdef-backdrop-filter",
)}
@ -84,6 +82,5 @@ ${helpers.single_keyword(
engines="gecko servo-2013 servo-2020",
gecko_enum_prefix="StyleBlend",
animation_value_type="discrete",
flags="CREATES_STACKING_CONTEXT",
spec="https://drafts.fxtf.org/compositing/#propdef-mix-blend-mode",
)}

View file

@ -60,7 +60,6 @@ ${helpers.predefined_type(
"computed::ZIndex::auto()",
engines="gecko servo-2013 servo-2020",
spec="https://www.w3.org/TR/CSS2/visuren.html#z-index",
flags="CREATES_STACKING_CONTEXT",
animation_value_type="ComputedValue",
)}

View file

@ -81,7 +81,6 @@ ${helpers.predefined_type(
"generics::basic_shape::ClipPath::None",
engines="gecko",
animation_value_type="basic_shape::ClipPath",
flags="CREATES_STACKING_CONTEXT",
spec="https://drafts.fxtf.org/css-masking/#propdef-clip-path",
)}
@ -183,7 +182,6 @@ ${helpers.predefined_type(
vector=True,
extra_prefixes="webkit",
animation_value_type="discrete",
flags="CREATES_STACKING_CONTEXT",
)}
${helpers.predefined_type(

View file

@ -1068,28 +1068,20 @@ impl CSSWideKeyword {
bitflags! {
/// A set of flags for properties.
pub struct PropertyFlags: u16 {
/// This property requires a stacking context.
const CREATES_STACKING_CONTEXT = 1 << 0;
/// This property has values that can establish a containing block for
/// fixed positioned and absolutely positioned elements.
const FIXPOS_CB = 1 << 1;
/// This property has values that can establish a containing block for
/// absolutely positioned elements.
const ABSPOS_CB = 1 << 2;
/// This longhand property applies to ::first-letter.
const APPLIES_TO_FIRST_LETTER = 1 << 3;
const APPLIES_TO_FIRST_LETTER = 1 << 1;
/// This longhand property applies to ::first-line.
const APPLIES_TO_FIRST_LINE = 1 << 4;
const APPLIES_TO_FIRST_LINE = 1 << 2;
/// This longhand property applies to ::placeholder.
const APPLIES_TO_PLACEHOLDER = 1 << 5;
const APPLIES_TO_PLACEHOLDER = 1 << 3;
/// This longhand property applies to ::cue.
const APPLIES_TO_CUE = 1 << 6;
const APPLIES_TO_CUE = 1 << 4;
/// This longhand property applies to ::marker.
const APPLIES_TO_MARKER = 1 << 7;
const APPLIES_TO_MARKER = 1 << 5;
/// This property is a legacy shorthand.
///
/// https://drafts.csswg.org/css-cascade/#legacy-shorthand
const IS_LEGACY_SHORTHAND = 1 << 8;
const IS_LEGACY_SHORTHAND = 1 << 6;
/* The following flags are currently not used in Rust code, they
* only need to be listed in corresponding properties so that

View file

@ -6,7 +6,7 @@
use crate::custom_properties::Name as CustomPropertyName;
use crate::parser::{Parse, ParserContext};
use crate::properties::{LonghandId, PropertyDeclarationId, PropertyFlags};
use crate::properties::{LonghandId, PropertyDeclarationId};
use crate::properties::{PropertyId, ShorthandId};
use crate::values::generics::box_::AnimationIterationCount as GenericAnimationIterationCount;
use crate::values::generics::box_::Perspective as GenericPerspective;
@ -1086,44 +1086,54 @@ bitflags! {
/// The change bits that we care about.
#[derive(Default, MallocSizeOf, SpecifiedValueInfo, ToComputedValue, ToResolvedValue, ToShmem)]
#[repr(C)]
pub struct WillChangeBits: u8 {
/// Whether the stacking context will change.
const STACKING_CONTEXT = 1 << 0;
/// Whether `transform` will change.
pub struct WillChangeBits: u16 {
/// Whether a property which can create a stacking context **on any
/// box** will change.
const STACKING_CONTEXT_UNCONDITIONAL = 1 << 0;
/// Whether `transform` or related properties will change.
const TRANSFORM = 1 << 1;
/// Whether `scroll-position` will change.
const SCROLL = 1 << 2;
/// Whether `contain` will change.
const CONTAIN = 1 << 3;
/// Whether `opacity` will change.
const OPACITY = 1 << 3;
/// Fixed pos containing block.
const FIXPOS_CB = 1 << 4;
/// Abs pos containing block.
const ABSPOS_CB = 1 << 5;
const OPACITY = 1 << 4;
/// Whether `perspective` will change.
const PERSPECTIVE = 1 << 5;
/// Whether `z-index` will change.
const Z_INDEX = 1 << 6;
/// Whether any property which creates a containing block for non-svg
/// text frames will change.
const FIXPOS_CB_NON_SVG = 1 << 7;
/// Whether the position property will change.
const POSITION = 1 << 8;
}
}
fn change_bits_for_longhand(longhand: LonghandId) -> WillChangeBits {
let mut flags = match longhand {
match longhand {
LonghandId::Opacity => WillChangeBits::OPACITY,
LonghandId::Transform => WillChangeBits::TRANSFORM,
#[cfg(feature = "gecko")]
LonghandId::Translate | LonghandId::Rotate | LonghandId::Scale | LonghandId::OffsetPath => {
WillChangeBits::TRANSFORM
LonghandId::Contain => WillChangeBits::CONTAIN,
LonghandId::Perspective => WillChangeBits::PERSPECTIVE,
LonghandId::Position => {
WillChangeBits::STACKING_CONTEXT_UNCONDITIONAL | WillChangeBits::POSITION
},
LonghandId::ZIndex => WillChangeBits::Z_INDEX,
LonghandId::Transform |
LonghandId::TransformStyle |
LonghandId::Translate |
LonghandId::Rotate |
LonghandId::Scale |
LonghandId::OffsetPath => WillChangeBits::TRANSFORM,
LonghandId::BackdropFilter | LonghandId::Filter => {
WillChangeBits::STACKING_CONTEXT_UNCONDITIONAL | WillChangeBits::FIXPOS_CB_NON_SVG
},
LonghandId::MixBlendMode |
LonghandId::Isolation |
LonghandId::MaskImage |
LonghandId::ClipPath => WillChangeBits::STACKING_CONTEXT_UNCONDITIONAL,
_ => WillChangeBits::empty(),
};
let property_flags = longhand.flags();
if property_flags.contains(PropertyFlags::CREATES_STACKING_CONTEXT) {
flags |= WillChangeBits::STACKING_CONTEXT;
}
if property_flags.contains(PropertyFlags::FIXPOS_CB) {
flags |= WillChangeBits::FIXPOS_CB;
}
if property_flags.contains(PropertyFlags::ABSPOS_CB) {
flags |= WillChangeBits::ABSPOS_CB;
}
flags
}
fn change_bits_for_maybe_property(ident: &str, context: &ParserContext) -> WillChangeBits {