tor-browser

commit b2460cab5357c8310c4d9e0bc031155982288f5d
parent 36d8a4108e1f0be382e56a30894f0355b9c36ed1
Author: Emilio Cobos Álvarez <emilio@crisal.io>
Date:   Tue, 30 Sep 2025 15:53:54 +0000

Bug 1991706 - Introduce position-fallback origin. r=layout-anchor-positioning-reviewers,dshin

As per https://drafts.csswg.org/css-anchor-position-1/#position-fallback-origin

We'll use this to resolve @position-try in the blocked bug.

Differential Revision: https://phabricator.services.mozilla.com/D266852

Diffstat:
M
dom/chrome-webidl/InspectorUtils.webidl
 | 
1
+
M
layout/inspector/InspectorUtils.cpp
 | 
2
++
M
servo/components/style/rule_tree/level.rs
 | 
5
+++++
M
servo/ports/geckolib/glue.rs
 | 
2
++

4 files changed, 10 insertions(+), 0 deletions(-)
diff --git a/dom/chrome-webidl/InspectorUtils.webidl b/dom/chrome-webidl/InspectorUtils.webidl
@@ -154,6 +154,7 @@ enum DeclarationOrigin {
   "user-agent",
   "pres-hints",
   "style-attribute",
+  "position-fallback",
   "animations",
   "transitions",
   "smil",
diff --git a/layout/inspector/InspectorUtils.cpp b/layout/inspector/InspectorUtils.cpp
@@ -424,6 +424,8 @@ static void GetCSSRulesFromComputedValues(
             return DeclarationOrigin::User;
           case StyleMatchingDeclarationBlockOrigin::UserAgent:
             return DeclarationOrigin::User_agent;
+          case StyleMatchingDeclarationBlockOrigin::PositionFallback:
+            return DeclarationOrigin::Position_fallback;
           case StyleMatchingDeclarationBlockOrigin::Animations:
             return DeclarationOrigin::Animations;
           case StyleMatchingDeclarationBlockOrigin::Transitions:
diff --git a/servo/components/style/rule_tree/level.rs b/servo/components/style/rule_tree/level.rs
@@ -50,6 +50,8 @@ pub enum CascadeLevel {
         ///    https://drafts.csswg.org/css-scoping/#shadow-cascading
         shadow_cascade_order: ShadowCascadeOrder,
     },
+    /// https://drafts.csswg.org/css-anchor-position-1/#position-fallback-origin
+    PositionFallback,
     /// SVG SMIL animations.
     SMILOverride,
     /// CSS animations and script-generated animations.
@@ -80,6 +82,7 @@ impl CascadeLevel {
                 shadow_cascade_order: -shadow_cascade_order,
             },
             Self::PresHints
+            | Self::PositionFallback
             | Self::SMILOverride
             | Self::Animations
             | Self::AuthorImportant { .. }
@@ -100,6 +103,7 @@ impl CascadeLevel {
                 shadow_cascade_order: -shadow_cascade_order,
             },
             Self::PresHints
+            | Self::PositionFallback
             | Self::SMILOverride
             | Self::Animations
             | Self::AuthorNormal { .. }
@@ -165,6 +169,7 @@ impl CascadeLevel {
             Self::UAImportant | Self::UANormal => Origin::UserAgent,
             Self::UserImportant | Self::UserNormal => Origin::User,
             Self::PresHints
+            | Self::PositionFallback { .. }
             | Self::AuthorNormal { .. }
             | Self::AuthorImportant { .. }
             | Self::SMILOverride
diff --git a/servo/ports/geckolib/glue.rs b/servo/ports/geckolib/glue.rs
@@ -4713,6 +4713,7 @@ pub enum MatchingDeclarationBlockOrigin {
     User,
     Author,
     PresHints,
+    PositionFallback,
     Animations,
     Transitions,
     SMIL,
@@ -4758,6 +4759,7 @@ pub extern "C" fn Servo_ComputedValues_GetMatchingDeclarations(
             CascadeLevel::AuthorNormal { .. } | CascadeLevel::AuthorImportant { .. } => {
                 MatchingDeclarationBlockOrigin::Author
             },
+            CascadeLevel::PositionFallback => MatchingDeclarationBlockOrigin::PositionFallback,
             CascadeLevel::PresHints => MatchingDeclarationBlockOrigin::PresHints,
             CascadeLevel::Animations => MatchingDeclarationBlockOrigin::Animations,
             CascadeLevel::Transitions => MatchingDeclarationBlockOrigin::Transitions,