tor-browser

commit b5aa6faa008b9aa0191c5671dafd558e86e3bb1b
parent 1e84ee418f199a3a1f3ea780299795e6dfa4b821
Author: Ting-Yu Lin <tlin@mozilla.com>
Date:   Tue, 25 Nov 2025 12:59:53 +0000

Bug 2001781 - Return nullptr from GetAbsoluteContainingBlock() when a frame is not an absolute container. r=dholbert,layout-reviewers

Differential Revision: https://phabricator.services.mozilla.com/D273941

Diffstat:
M
layout/generic/nsBlockFrame.cpp
 | 
3
+--
M
layout/generic/nsContainerFrame.cpp
 | 
7
+++----
M
layout/generic/nsGridContainerFrame.cpp
 | 
8
+++-----
M
layout/generic/nsIFrame.cpp
 | 
17
++++++++---------

4 files changed, 15 insertions(+), 20 deletions(-)
diff --git a/layout/generic/nsBlockFrame.cpp b/layout/generic/nsBlockFrame.cpp
@@ -1646,8 +1646,7 @@ void nsBlockFrame::Reflow(nsPresContext* aPresContext, ReflowOutput& aMetrics,
   // resetting the size. Because of this, we must not reflow our abs-pos
   // children in that situation --- what we think is our "new size" will not be
   // our real new size. This also happens to be more efficient.
-  AbsoluteContainingBlock* absoluteContainer =
-      IsAbsoluteContainer() ? GetAbsoluteContainingBlock() : nullptr;
+  auto* absoluteContainer = GetAbsoluteContainingBlock();
   if (absoluteContainer && absoluteContainer->PrepareAbsoluteFrames(this)) {
     bool haveInterrupt = aPresContext->HasPendingInterrupt();
     if (aReflowInput.WillReflowAgainForClearance() || haveInterrupt) {
diff --git a/layout/generic/nsContainerFrame.cpp b/layout/generic/nsContainerFrame.cpp
@@ -181,8 +181,8 @@ void nsContainerFrame::RemoveFrame(DestroyContext& aContext,
 }
 
 void nsContainerFrame::DestroyAbsoluteFrames(DestroyContext& aContext) {
-  if (IsAbsoluteContainer()) {
-    GetAbsoluteContainingBlock()->DestroyFrames(aContext);
+  if (auto* absCB = GetAbsoluteContainingBlock()) {
+    absCB->DestroyFrames(aContext);
     MarkAsNotAbsoluteContainingBlock();
   }
 }
@@ -846,8 +846,7 @@ void nsContainerFrame::ReflowAbsoluteFrames(nsPresContext* aPresContext,
                                             ReflowOutput& aDesiredSize,
                                             const ReflowInput& aReflowInput,
                                             nsReflowStatus& aStatus) {
-  AbsoluteContainingBlock* absoluteContainer =
-      IsAbsoluteContainer() ? GetAbsoluteContainingBlock() : nullptr;
+  auto* absoluteContainer = GetAbsoluteContainingBlock();
   if (absoluteContainer && absoluteContainer->PrepareAbsoluteFrames(this)) {
     // The containing block for the abs pos kids is formed by our padding edge.
     const auto wm = GetWritingMode();
diff --git a/layout/generic/nsGridContainerFrame.cpp b/layout/generic/nsGridContainerFrame.cpp
@@ -3276,10 +3276,9 @@ struct MOZ_STACK_CLASS nsGridContainerFrame::GridReflowInput {
       MOZ_ASSERT(mGridItems.Length() == len + 1, "can't find GridItemInfo");
     }
 
-    if (aGridContainerFrame->IsAbsoluteContainer()) {
+    if (auto* absCB = aGridContainerFrame->GetAbsoluteContainingBlock()) {
       // Prepare absolute frames before constructing GridItemInfo.
-      aGridContainerFrame->GetAbsoluteContainingBlock()->PrepareAbsoluteFrames(
-          aGridContainerFrame);
+      absCB->PrepareAbsoluteFrames(aGridContainerFrame);
     }
     // XXX NOTE: This is O(n^2) in the number of abs.pos. items. (bug 1252186)
     const nsFrameList& absPosChildren = aGridContainerFrame->GetChildList(
@@ -9304,8 +9303,7 @@ nscoord nsGridContainerFrame::ReflowChildren(GridReflowInput& aGridRI,
   aDesiredSize.mOverflowAreas.UnionWith(ocBounds);
   aStatus.MergeCompletionStatusFrom(ocStatus);
 
-  AbsoluteContainingBlock* absoluteContainer =
-      IsAbsoluteContainer() ? GetAbsoluteContainingBlock() : nullptr;
+  auto* absoluteContainer = GetAbsoluteContainingBlock();
   // We have prepared the absolute frames when initializing GridReflowInput.
   if (absoluteContainer && absoluteContainer->HasAbsoluteFrames()) {
     // 'gridOrigin' is the origin of the grid (the start of the first track),
diff --git a/layout/generic/nsIFrame.cpp b/layout/generic/nsIFrame.cpp
@@ -259,13 +259,14 @@ NS_DECLARE_FRAME_PROPERTY_DELETABLE(AbsoluteContainingBlockProperty,
                                     AbsoluteContainingBlock)
 
 bool nsIFrame::HasAbsolutelyPositionedChildren() const {
-  return IsAbsoluteContainer() &&
-         GetAbsoluteContainingBlock()->HasAbsoluteFrames();
+  const auto* absCB = GetAbsoluteContainingBlock();
+  return absCB && absCB->HasAbsoluteFrames();
 }
 
 AbsoluteContainingBlock* nsIFrame::GetAbsoluteContainingBlock() const {
-  NS_ASSERTION(IsAbsoluteContainer(),
-               "The frame is not marked as an abspos container correctly");
+  if (!IsAbsoluteContainer()) {
+    return nullptr;
+  }
   AbsoluteContainingBlock* absCB =
       GetProperty(AbsoluteContainingBlockProperty());
   NS_ASSERTION(absCB,
@@ -2039,8 +2040,7 @@ const nsFrameList& nsIFrame::GetChildList(ChildListID aListID) const {
 }
 
 void nsIFrame::GetChildLists(nsTArray<ChildList>* aLists) const {
-  if (IsAbsoluteContainer()) {
-    const auto* absCB = GetAbsoluteContainingBlock();
+  if (const auto* absCB = GetAbsoluteContainingBlock()) {
     const nsFrameList& absoluteList = absCB->GetChildList();
     absoluteList.AppendIfNonempty(aLists, GetAbsoluteListID());
     const nsFrameList& pushedAbsoluteList = absCB->GetPushedChildList();
@@ -4573,9 +4573,8 @@ void nsIFrame::BuildDisplayListForChild(nsDisplayListBuilder* aBuilder,
 
 void nsIFrame::MarkAbsoluteFramesForDisplayList(
     nsDisplayListBuilder* aBuilder) {
-  if (IsAbsoluteContainer()) {
-    aBuilder->MarkFramesForDisplayList(
-        this, GetAbsoluteContainingBlock()->GetChildList());
+  if (const auto* absCB = GetAbsoluteContainingBlock()) {
+    aBuilder->MarkFramesForDisplayList(this, absCB->GetChildList());
   }
 }