tor-browser

commit 718cc9cec13a37bfc4c1fbfa8333dc086d2f8512
parent 18b3d129d06daf968131a3c8416413f2e2fd3366
Author: Emilio Cobos Álvarez <emilio@crisal.io>
Date:   Wed, 29 Oct 2025 13:00:04 +0000

Bug 1997040 - Make DepthOrderedFrameList insertion not scan the whole array. r=jfkthame,layout-reviewers

Differential Revision: https://phabricator.services.mozilla.com/D270483

Diffstat:
M
layout/base/DepthOrderedFrameList.cpp
 | 
19
++++++++-----------
M
layout/base/DepthOrderedFrameList.h
 | 
9
+++++++--

2 files changed, 15 insertions(+), 13 deletions(-)
diff --git a/layout/base/DepthOrderedFrameList.cpp b/layout/base/DepthOrderedFrameList.cpp
@@ -13,19 +13,16 @@ namespace mozilla {
 
 void DepthOrderedFrameList::Add(nsIFrame* aFrame) {
   // Is this root already scheduled for reflow?
-  // FIXME: This could possibly be changed to a uniqueness assertion, with some
-  // work in ResizeReflowIgnoreOverride (and maybe others?)
-  // FIXME(emilio): Should probably reuse the traversal for insertion.
-  if (Contains(aFrame)) {
-    // We don't expect frame to change depths.
-    MOZ_ASSERT(aFrame->GetDepthInFrameTree() ==
-               mList[mList.IndexOf(aFrame)].mDepth);
+  FrameAndDepth entry{aFrame, aFrame->GetDepthInFrameTree()};
+  auto index = mList.IndexOfFirstElementGt(
+      entry, FrameAndDepth::CompareByReverseDepth{});
+  if (MOZ_UNLIKELY(index > 0 && mList[index - 1].mFrame == aFrame)) {
+    // FIXME: This could possibly be changed to a uniqueness assertion, with
+    // some work in ResizeReflowIgnoreOverride (and maybe others?)
+    MOZ_ASSERT(mList[index - 1].mDepth == entry.mDepth);
     return;
   }
-
-  mList.InsertElementSorted(
-      FrameAndDepth{aFrame, aFrame->GetDepthInFrameTree()},
-      FrameAndDepth::CompareByReverseDepth{});
+  mList.InsertElementAt(index, std::move(entry));
 }
 
 void DepthOrderedFrameList::Remove(nsIFrame* aFrame) {
diff --git a/layout/base/DepthOrderedFrameList.h b/layout/base/DepthOrderedFrameList.h
@@ -52,11 +52,16 @@ class DepthOrderedFrameList {
     class CompareByReverseDepth {
      public:
       bool Equals(const FrameAndDepth& aA, const FrameAndDepth& aB) const {
-        return aA.mDepth == aB.mDepth;
+        return aA.mFrame == aB.mFrame;
       }
       bool LessThan(const FrameAndDepth& aA, const FrameAndDepth& aB) const {
         // Reverse depth! So '>' instead of '<'.
-        return aA.mDepth > aB.mDepth;
+        if (aA.mDepth != aB.mDepth) {
+          return aA.mDepth > aB.mDepth;
+        }
+        // Untie with the frame pointer, so that all frames have a unique
+        // position in the sorted list.
+        return uintptr_t(aA.mFrame) < uintptr_t(aB.mFrame);
       }
     };
   };