From 63da1ccbd0af26b4edaa6fc9f04775564cbb6a56 Mon Sep 17 00:00:00 2001
From: "bzbarsky%mit.edu"
 <bzbarsky%mit.edu@18797224-902f-48f8-a5cc-f745e15eee43>
Date: Thu, 1 Sep 2005 02:40:12 +0000
Subject: [PATCH] Make sure to null out the weak parent ptr in session history
 entries as needed.  Bug 305181, r=bryner, sr=jst

git-svn-id: svn://10.0.0.236/trunk@179451 18797224-902f-48f8-a5cc-f745e15eee43
---
 mozilla/docshell/shistory/src/nsSHEntry.cpp | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/mozilla/docshell/shistory/src/nsSHEntry.cpp b/mozilla/docshell/shistory/src/nsSHEntry.cpp
index e7a1dbce12c..361ca62a568 100644
--- a/mozilla/docshell/shistory/src/nsSHEntry.cpp
+++ b/mozilla/docshell/shistory/src/nsSHEntry.cpp
@@ -99,8 +99,20 @@ nsSHEntry::nsSHEntry(const nsSHEntry &other)
 {
 }
 
+PR_STATIC_CALLBACK(PRBool)
+ClearParentPtr(nsISHEntry* aEntry, void* /* aData */)
+{
+  if (aEntry) {
+    aEntry->SetParent(nsnull);
+  }
+  return PR_TRUE;
+}
+
 nsSHEntry::~nsSHEntry()
 {
+  // Since we never really remove kids from SHEntrys, we need to null
+  // out the mParent pointers on all our kids.
+  mChildren.EnumerateForwards(ClearParentPtr, nsnull);
   mChildren.Clear();
   RemoveDocumentObserver();
   if (mContentViewer)
@@ -469,6 +481,15 @@ nsSHEntry::AddChild(nsISHEntry * aChild, PRInt32 aOffset)
   //
   NS_ASSERTION(aOffset < (mChildren.Count()+1023), "Large frames array!\n");
 
+  if (aOffset < mChildren.Count()) {
+    nsISHEntry* oldChild = mChildren.ObjectAt(aOffset);
+    if (oldChild && oldChild != aChild) {
+      NS_ERROR("Adding child where we already have a child?  "
+               "This will likely misbehave");
+      oldChild->SetParent(nsnull);
+    }
+  }
+  
   // This implicitly extends the array to include aOffset
   mChildren.ReplaceObjectAt(aChild, aOffset);