Bug 1897756. Implement parsing of CSS 'position-visibility' property. r=emilio

Differential Revision: https://phabricator.services.mozilla.com/D210910

devtools/server/actors/animation-type-longhand.js

@@ -144,6 +144,7 @@ exports.ANIMATION_TYPE_FOR_LONGHANDS = [
       "pointer-events",
       "position",
       "position-anchor",
+      "position-visibility",
       "print-color-adjust",
       "quotes",
       "resize",

dom/base/use_counter_metrics.yaml

@@ -107,7 +107,7 @@ use.counter:
     send_in_pings:
       - use-counters
 
-# Total of 2307 use counter metrics (excludes denominators).
+# Total of 2309 use counter metrics (excludes denominators).
 # Total of 354 'page' use counters.
 use.counter.page:
   svgsvgelement_getelementbyid:
@@ -15541,7 +15541,7 @@ use.counter.deprecated_ops.doc:
     send_in_pings:
       - use-counters
 
-# Total of 700 'CSS (page)' use counters.
+# Total of 701 'CSS (page)' use counters.
 use.counter.css.page:
   css_align_content:
     type: counter
@@ -17039,6 +17039,23 @@ use.counter.css.page:
     send_in_pings:
       - use-counters
 
+  css_position_visibility:
+    type: counter
+    description: >
+      Whether a page used the CSS property position-visibility.
+      Compare against `use.counter.top_level_content_documents_destroyed`
+      to calculate the rate.
+    bugs:
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1852098
+    data_reviews:
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1852098
+    notification_emails:
+      - dom-core@mozilla.com
+      - emilio@mozilla.com
+    expires: never
+    send_in_pings:
+      - use-counters
+
   css_print_color_adjust:
     type: counter
     description: >
@@ -27443,7 +27460,7 @@ use.counter.css.page:
     send_in_pings:
       - use-counters
 
-# Total of 700 'CSS (document)' use counters.
+# Total of 701 'CSS (document)' use counters.
 use.counter.css.doc:
   css_align_content:
     type: counter
@@ -28941,6 +28958,23 @@ use.counter.css.doc:
     send_in_pings:
       - use-counters
 
+  css_position_visibility:
+    type: counter
+    description: >
+      Whether a document used the CSS property position-visibility.
+      Compare against `use.counter.content_documents_destroyed`
+      to calculate the rate.
+    bugs:
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1852098
+    data_reviews:
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1852098
+    notification_emails:
+      - dom-core@mozilla.com
+      - emilio@mozilla.com
+    expires: never
+    send_in_pings:
+      - use-counters
+
   css_print_color_adjust:
     type: counter
     description: >

layout/style/ServoBindings.toml

@@ -623,6 +623,7 @@ cbindgen-types = [
     { gecko = "StyleAnchorName", servo = "crate::values::computed::position::AnchorName" },
     { gecko = "StyleAnchorScope", servo = "crate::values::computed::position::AnchorScope" },
     { gecko = "StylePositionAnchor", servo = "crate::values::computed::position::PositionAnchor" },
+    { gecko = "StylePositionVisibility", servo = "crate::values::computed::position::PositionVisibility" },
 ]
 
 mapped-generic-types = [

layout/style/nsStyleStruct.cpp

@@ -1052,6 +1052,7 @@ nsStylePosition::nsStylePosition()
       mMinHeight(StyleSize::Auto()),
       mMaxHeight(StyleMaxSize::None()),
       mPositionAnchor(StylePositionAnchor::Auto()),
+      mPositionVisibility(StylePositionVisibility::ALWAYS),
       mFlexBasis(StyleFlexBasis::Size(StyleSize::Auto())),
       mAspectRatio(StyleAspectRatio::Auto()),
       mGridAutoFlow(StyleGridAutoFlow::ROW),
@@ -1101,6 +1102,7 @@ nsStylePosition::nsStylePosition(const nsStylePosition& aSource)
       mMinHeight(aSource.mMinHeight),
       mMaxHeight(aSource.mMaxHeight),
       mPositionAnchor(aSource.mPositionAnchor),
+      mPositionVisibility(aSource.mPositionVisibility),
       mFlexBasis(aSource.mFlexBasis),
       mGridAutoColumns(aSource.mGridAutoColumns),
       mGridAutoRows(aSource.mGridAutoRows),
@@ -1285,6 +1287,10 @@ nsChangeHint nsStylePosition::CalcDifference(
     hint |= nsChangeHint_NeutralChange;
   }
 
+  if (mPositionVisibility != aNewData.mPositionVisibility) {
+    hint |= nsChangeHint_NeutralChange;
+  }
+
   if (mAspectRatio != aNewData.mAspectRatio) {
     hint |= nsChangeHint_ReflowHintsForISizeChange |
             nsChangeHint_ReflowHintsForBSizeChange;

layout/style/nsStyleStruct.h

@@ -748,6 +748,7 @@ struct MOZ_NEEDS_MEMMOVABLE_MEMBERS nsStylePosition {
   // 'auto' or a `<dashed-ident>` referencing an anchor positioning anchor
   // element.
   mozilla::StylePositionAnchor mPositionAnchor;
+  mozilla::StylePositionVisibility mPositionVisibility;
 
   mozilla::StyleFlexBasis mFlexBasis;
   StyleImplicitGridTracks mGridAutoColumns;

layout/style/test/property_database.js

@@ -13346,6 +13346,20 @@ if (IsCSSPropertyPrefEnabled("layout.css.anchor-positioning.enabled")) {
     other_values: ["--foo"],
     invalid_values: ["none", "--foo, auto", "auto, --bar", "foo"],
   };
+
+  gCSSProperties["position-visibility"] = {
+    domProp: "positionVisibility",
+    inherited: false,
+    type: CSS_TYPE_LONGHAND,
+    initial_values: ["always"],
+    other_values: ["anchors-valid", "anchors-visible", "no-overflow"],
+    invalid_values: [
+      "none",
+      "auto",
+      "always anchors-valid",
+      "anchors-visible always",
+    ],
+  };
 }
 
 if (false) {

servo/components/style/properties/data.py

@@ -591,6 +591,7 @@ class Longhand(Property):
                 "OverscrollBehavior",
                 "PageOrientation",
                 "Percentage",
+                "PositionVisibility",
                 "PrintColorAdjust",
                 "ForcedColorAdjust",
                 "Resize",

servo/components/style/properties/longhands/position.mako.rs

@@ -342,6 +342,18 @@ ${helpers.predefined_type(
     affects="layout",
 )}
 
+${helpers.predefined_type(
+    "position-visibility",
+    "PositionVisibility",
+    "computed::PositionVisibility::ALWAYS",
+    engines="gecko",
+    initial_specified_value="specified::PositionVisibility::ALWAYS",
+    animation_value_type="discrete",
+    gecko_pref="layout.css.anchor-positioning.enabled",
+    spec="https://drafts.csswg.org/css-anchor-position-1/#propdef-position-visibility",
+    affects="layout",
+)}
+
 ${helpers.single_keyword(
     "box-sizing",
     "content-box border-box",

servo/components/style/values/computed/mod.rs

@@ -91,6 +91,7 @@ pub use self::percentage::{NonNegativePercentage, Percentage};
 pub use self::position::AnchorName;
 pub use self::position::AnchorScope;
 pub use self::position::PositionAnchor;
+pub use self::position::PositionVisibility;
 pub use self::position::AspectRatio;
 pub use self::position::{
     GridAutoFlow, GridTemplateAreas, MasonryAutoFlow, Position, PositionOrAuto, ZIndex,

servo/components/style/values/computed/position.rs

@@ -14,7 +14,7 @@ use crate::values::generics::position::PositionComponent as GenericPositionCompo
 use crate::values::generics::position::PositionOrAuto as GenericPositionOrAuto;
 use crate::values::generics::position::ZIndex as GenericZIndex;
 pub use crate::values::specified::position::{GridAutoFlow, GridTemplateAreas, MasonryAutoFlow};
-pub use crate::values::specified::position::{AnchorName, AnchorScope, PositionAnchor};
+pub use crate::values::specified::position::{AnchorName, AnchorScope, PositionAnchor, PositionVisibility};
 use crate::Zero;
 use std::fmt::{self, Write};
 use style_traits::{CssWriter, ToCss};

servo/components/style/values/specified/mod.rs

@@ -84,6 +84,7 @@ pub use self::position::AspectRatio;
 pub use self::position::AnchorName;
 pub use self::position::AnchorScope;
 pub use self::position::PositionAnchor;
+pub use self::position::PositionVisibility;
 pub use self::position::{GridAutoFlow, GridTemplateAreas, Position, PositionOrAuto};
 pub use self::position::{MasonryAutoFlow, MasonryItemOrder, MasonryPlacement};
 pub use self::position::{PositionComponent, ZIndex};

servo/components/style/values/specified/position.rs

@@ -489,6 +489,52 @@ impl PositionAnchor {
     }
 }
 
+#[derive(
+    Clone,
+    Copy,
+    Debug,
+    Eq,
+    MallocSizeOf,
+    Parse,
+    PartialEq,
+    Serialize,
+    SpecifiedValueInfo,
+    ToComputedValue,
+    ToCss,
+    ToResolvedValue,
+    ToShmem,
+)]
+#[css(bitflags(single = "always", mixed = "anchors-valid,anchors-visible,no-overflow"))]
+#[repr(C)]
+/// Specified keyword values for the position-visibility property.
+pub struct PositionVisibility(u8);
+bitflags! {
+    impl PositionVisibility: u8 {
+        /// Element is displayed without regard for its anchors or its overflowing status.
+        const ALWAYS = 0;
+        /// anchors-valid
+        const ANCHORS_VALID = 1 << 0;
+        /// anchors-visible
+        const ANCHORS_VISIBLE = 1 << 1;
+        /// no-overflow
+        const NO_OVERFLOW = 1 << 2;
+    }
+}
+
+impl Default for PositionVisibility {
+    fn default() -> Self {
+        Self::ALWAYS
+    }
+}
+
+impl PositionVisibility {
+    #[inline]
+    /// Returns the initial value of position-visibility
+    pub fn always() -> Self {
+        Self::ALWAYS
+    }
+}
+
 /// Represents a side, either horizontal or vertical, of a CSS position.
 pub trait Side {
     /// Returns the start side.

servo/ports/geckolib/cbindgen.toml

@@ -112,6 +112,7 @@ include = [
   "DisplayMode",
   "Platform",
   "PositionAnchor",
+  "PositionVisibility",
   "GtkThemeFamily",
   "PrefersColorScheme",
   "PrefersContrast",