From e3476d33ed811937c296711c79d2e2db1f9456ac Mon Sep 17 00:00:00 2001
From: Francis Dominic Fajardo <fofajardo@up.edu.ph>
Date: Tue, 22 Jul 2025 12:29:41 +0800
Subject: [PATCH] Issue #2828 - Part 12: Implement cascade layer
 SizeOfIncludingThis

---
 layout/style/CascadeLayerRuleProcessor.cpp |  5 ++--
 layout/style/RuleCascadeData.cpp           | 28 ++++++++++++++++++++++
 layout/style/RuleCascadeData.h             |  2 ++
 3 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/layout/style/CascadeLayerRuleProcessor.cpp b/layout/style/CascadeLayerRuleProcessor.cpp
index 897a010280..b5652b7423 100644
--- a/layout/style/CascadeLayerRuleProcessor.cpp
+++ b/layout/style/CascadeLayerRuleProcessor.cpp
@@ -223,8 +223,9 @@ CascadeLayerRuleProcessor::SizeOfExcludingThis(
   mozilla::MallocSizeOf aMallocSizeOf) const
 {
   size_t n = 0;
-  n += mCascade->SizeOfIncludingThis(aMallocSizeOf);
-  // FIXME: size of attached cascade layer is not included.
+  // The cascade layer owns the rule cascade, so we don't count it here.
+  // We do count the layer itself, though.
+  n += mLayer->SizeOfIncludingThis(aMallocSizeOf);
 
   return n;
 }
diff --git a/layout/style/RuleCascadeData.cpp b/layout/style/RuleCascadeData.cpp
index 465225d792..3a78e3e84e 100644
--- a/layout/style/RuleCascadeData.cpp
+++ b/layout/style/RuleCascadeData.cpp
@@ -1642,6 +1642,34 @@ CascadeLayer::~CascadeLayer()
   delete mData;
 }
 
+size_t
+CascadeLayer::SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const
+{
+  size_t n = aMallocSizeOf(this);
+  if (mData) {
+    n += mData->SizeOfIncludingThis(aMallocSizeOf);
+  }
+  n += mName.SizeOfExcludingThisIfUnshared(aMallocSizeOf);
+  n += mStyleRules.ShallowSizeOfExcludingThis(aMallocSizeOf);
+  // While we do create the child layers, they are not owned by us, so we
+  // don't count them. Their ownership is managed by the rule processor
+  // to which they are eventually attached (see nsCSSRuleProcessor).
+  n += mPreLayers.ShallowSizeOfExcludingThis(aMallocSizeOf);
+  n += mPostLayers.ShallowSizeOfExcludingThis(aMallocSizeOf);
+  n += mLayers.ShallowSizeOfExcludingThis(aMallocSizeOf);
+  for (auto iter = mLayers.ConstIter(); !iter.Done(); iter.Next()) {
+    // We don't own the CascadeLayer objects so we don't count them. We
+    // do care about the size of the keys' nsAString members' buffers though.
+    //
+    // Note that we depend on nsStringHashKey::GetKey() returning a reference,
+    // since otherwise aKey would be a copy of the string key and we would not
+    // be measuring the right object here.
+    n += iter.Key().SizeOfExcludingThisIfUnshared(aMallocSizeOf);
+  }
+
+  return n;
+}
+
 CascadeLayer*
 CascadeLayer::CreateNamedChildLayer(const nsTArray<nsString>& aPath)
 {
diff --git a/layout/style/RuleCascadeData.h b/layout/style/RuleCascadeData.h
index 1986377924..1a8b4efd07 100644
--- a/layout/style/RuleCascadeData.h
+++ b/layout/style/RuleCascadeData.h
@@ -336,6 +336,8 @@ struct CascadeLayer
                nsMediaQueryResultCacheKey& aCacheKey);
   ~CascadeLayer();
 
+  size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const;
+
   nsPresContext* mPresContext;
   nsString mName;
   bool mIsAnonymous;