style: Remove damage_handled, and use a reconstructed_ancestor bit instead.

Reviewed-By: bholley
Bug: 1368236
MozReview-Commit-ID: 8KK0YfhiS2

components/layout_thread/lib.rs

@@ -111,9 +111,9 @@ use std::thread;
 use style::animation::Animation;
 use style::context::{QuirksMode, ReflowGoal, SharedStyleContext};
 use style::context::{StyleSystemOptions, ThreadLocalStyleContextCreationInfo};
-use style::data::StoredRestyleHint;
 use style::dom::{ShowSubtree, ShowSubtreeDataAndPrimaryValues, TElement, TNode};
 use style::error_reporting::{NullReporter, RustLogReporter};
+use style::invalidation::element::restyle_hints::RestyleHint;
 use style::logical_geometry::LogicalPoint;
 use style::media_queries::{Device, MediaList, MediaType};
 use style::selector_parser::SnapshotMap;
@@ -1119,7 +1119,7 @@ impl LayoutThread {
                         let el = node.as_element().unwrap();
                         if let Some(mut d) = element.mutate_data() {
                             if d.has_styles() {
-                                d.ensure_restyle().hint.insert(StoredRestyleHint::subtree());
+                                d.ensure_restyle().hint.insert(RestyleHint::restyle_subtree());
                             }
                         }
                         if let Some(p) = el.parent_element() {
@@ -1155,7 +1155,7 @@ impl LayoutThread {
         if needs_dirtying {
             if let Some(mut d) = element.mutate_data() {
                 if d.has_styles() {
-                    d.ensure_restyle().hint.insert(StoredRestyleHint::subtree());
+                    d.ensure_restyle().hint.insert(RestyleHint::restyle_subtree());
                 }
             }
         }

components/style/data.rs

@@ -357,19 +357,12 @@ pub struct RestyleData {
     /// for this element, its children, and its descendants.
     pub hint: RestyleHint,
 
+    /// Whether we reframed/reconstructed any ancestor or self.
+    pub reconstructed_ancestor: bool,
+
     /// The restyle damage, indicating what kind of layout changes are required
     /// afte restyling.
     pub damage: RestyleDamage,
-
-    /// The restyle damage that has already been handled by our ancestors, and does
-    /// not need to be applied again at this element. Only non-empty during the
-    /// traversal, once ancestor damage has been calculated.
-    ///
-    /// Note that this optimization mostly makes sense in terms of Gecko's top-down
-    /// frame constructor and change list processing model. We don't bother with it
-    /// for Servo for now.
-    #[cfg(feature = "gecko")]
-    pub damage_handled: RestyleDamage,
 }
 
 impl RestyleData {
@@ -377,28 +370,6 @@ impl RestyleData {
     pub fn has_invalidations(&self) -> bool {
         self.hint.has_self_invalidations()
     }
-
-    /// Returns damage handled.
-    #[cfg(feature = "gecko")]
-    pub fn damage_handled(&self) -> RestyleDamage {
-        self.damage_handled
-    }
-
-    /// Returns damage handled (always empty for servo).
-    #[cfg(feature = "servo")]
-    pub fn damage_handled(&self) -> RestyleDamage {
-        RestyleDamage::empty()
-    }
-
-    /// Sets damage handled.
-    #[cfg(feature = "gecko")]
-    pub fn set_damage_handled(&mut self, d: RestyleDamage) {
-        self.damage_handled = d;
-    }
-
-    /// Sets damage handled. No-op for Servo.
-    #[cfg(feature = "servo")]
-    pub fn set_damage_handled(&mut self, _: RestyleDamage) {}
 }
 
 /// Style system data associated with an Element.

components/style/matching.rs

@@ -697,8 +697,8 @@ trait PrivateMatchMethods: TElement {
         // for followup work to make the optimization here more optimal by considering
         // each bit individually.
         let skip_applying_damage =
-            restyle.damage_handled.contains(RestyleDamage::reconstruct()) ||
-            restyle.damage.contains(RestyleDamage::reconstruct());
+            restyle.damage.contains(RestyleDamage::reconstruct()) ||
+            restyle.reconstructed_ancestor;
 
         let difference = self.compute_style_difference(&old_values,
                                                        &new_values,

components/style/traversal.rs

@@ -297,8 +297,8 @@ pub trait DomTraversal<E: TElement> : Sync {
             if let Some(parent) = el.traversal_parent() {
                 let parent_data = parent.borrow_data().unwrap();
                 let going_to_reframe = parent_data.get_restyle().map_or(false, |r| {
-                    (r.damage | r.damage_handled())
-                        .contains(RestyleDamage::reconstruct())
+                    r.reconstructed_ancestor ||
+                    r.damage.contains(RestyleDamage::reconstruct())
                 });
 
                 let mut is_before_or_after_pseudo = false;
@@ -730,14 +730,16 @@ pub fn recalc_style_at<E, D>(traversal: &D,
                                           DontLog) &&
         (has_dirty_descendants_for_this_restyle ||
          !propagated_hint.is_empty()) {
-        let damage_handled = data.get_restyle().map_or(RestyleDamage::empty(), |r| {
-            r.damage_handled() | r.damage.handled_for_descendants()
+        let reconstructed_ancestor = data.get_restyle().map_or(false, |r| {
+            r.reconstructed_ancestor ||
+            r.damage.contains(RestyleDamage::reconstruct())
         });
-
-        preprocess_children::<E, D>(context,
+        preprocess_children::<E, D>(
+            context,
             element,
             propagated_hint,
-                                    damage_handled);
+            reconstructed_ancestor,
+        )
     }
 
     // If we are in a restyle for reconstruction, drop the existing restyle
@@ -840,11 +842,14 @@ fn compute_style<E, D>(_traversal: &D,
     }
 }
 
-fn preprocess_children<E, D>(context: &mut StyleContext<E>,
+fn preprocess_children<E, D>(
+    context: &mut StyleContext<E>,
     element: E,
     propagated_hint: RestyleHint,
-                             damage_handled: RestyleDamage)
-    where E: TElement,
+    reconstructed_ancestor: bool,
+)
+where
+    E: TElement,
     D: DomTraversal<E>,
 {
     trace!("preprocess_children: {:?}", element);
@@ -880,9 +885,7 @@ fn preprocess_children<E, D>(context: &mut StyleContext<E>,
         // If the child doesn't have pre-existing RestyleData and we don't have
         // any reason to create one, avoid the useless allocation and move on to
         // the next child.
-        if propagated_hint.is_empty() &&
-            damage_handled.is_empty() &&
-            !child_data.has_restyle() {
+        if !reconstructed_ancestor && propagated_hint.is_empty() && !child_data.has_restyle() {
             continue;
         }
 
@@ -890,10 +893,8 @@ fn preprocess_children<E, D>(context: &mut StyleContext<E>,
 
         // Propagate the parent restyle hint, that may make us restyle the whole
         // subtree.
+        restyle_data.reconstructed_ancestor = reconstructed_ancestor;
         restyle_data.hint.insert(propagated_hint);
-
-        // Store the damage already handled by ancestors.
-        restyle_data.set_damage_handled(damage_handled);
     }
 }