From a4e3731e4adb2ddeb7f07099ee99ebafd7b6b3b9 Mon Sep 17 00:00:00 2001
From: "bzbarsky%mit.edu"
 <bzbarsky%mit.edu@18797224-902f-48f8-a5cc-f745e15eee43>
Date: Wed, 1 Jun 2005 15:43:08 +0000
Subject: [PATCH] Fix memory leak if a viewmanager has a child viewmanager. 
 Bug 295656, r+sr=roc, a=shaver

git-svn-id: svn://10.0.0.236/trunk@173924 18797224-902f-48f8-a5cc-f745e15eee43
---
 mozilla/view/src/nsViewManager.cpp | 20 ++++++++++----------
 mozilla/view/src/nsViewManager.h   |  3 ++-
 2 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/mozilla/view/src/nsViewManager.cpp b/mozilla/view/src/nsViewManager.cpp
index a6a41e05e2e..b20892007b6 100644
--- a/mozilla/view/src/nsViewManager.cpp
+++ b/mozilla/view/src/nsViewManager.cpp
@@ -453,6 +453,7 @@ PRUint32 nsViewManager::gLastUserEventTime = 0;
 nsViewManager::nsViewManager()
   : mMouseLocation(NSCOORD_NONE, NSCOORD_NONE)
   , mDelayedResize(NSCOORD_NONE, NSCOORD_NONE)
+  , mRootViewManager(this)
 {
   if (gViewManagers == nsnull) {
     NS_ASSERTION(mVMCount == 0, "View Manager count is incorrect");
@@ -497,7 +498,7 @@ nsViewManager::~nsViewManager()
   
   if (!IsRootVM()) {
     // We have a strong ref to mRootViewManager
-    NS_IF_RELEASE(mRootViewManager);
+    NS_RELEASE(mRootViewManager);
   }
   
   mInvalidateEventQueue = nsnull;  
@@ -640,22 +641,21 @@ NS_IMETHODIMP nsViewManager::SetRootView(nsIView *aView)
 {
   nsView* view = NS_STATIC_CAST(nsView*, aView);
 
+  NS_PRECONDITION(!view || view->GetViewManager() == this,
+                  "Unexpected viewmanager on root view");
+  
   // Do NOT destroy the current root view. It's the caller's responsibility
   // to destroy it
   mRootView = view;
 
   if (mRootView) {
-    if (mRootViewManager && mRootViewManager != this) {
-      NS_RELEASE(mRootViewManager);
-    }
     nsView* parent = mRootView->GetParent();
     if (parent) {
+      // Calling InsertChild on |parent| will InvalidateHierarchy() on us, so
+      // no need to set mRootViewManager ourselves here.
       parent->InsertChild(mRootView, nsnull);
-      mRootViewManager = parent->GetViewManager()->RootViewManager();
-      NS_ASSERTION(mRootViewManager != this, "Something's wrong");
-      NS_ADDREF(mRootViewManager);
     } else {
-      mRootViewManager = this;
+      InvalidateHierarchy();
     }
 
     mRootView->SetZIndex(PR_FALSE, 0, PR_FALSE);
@@ -4447,8 +4447,8 @@ void
 nsViewManager::InvalidateHierarchy()
 {
   if (mRootView) {
-    if (mRootViewManager != this) {
-      NS_IF_RELEASE(mRootViewManager);
+    if (!IsRootVM()) {
+      NS_RELEASE(mRootViewManager);
     }
     nsView *parent = mRootView->GetParent();
     if (parent) {
diff --git a/mozilla/view/src/nsViewManager.h b/mozilla/view/src/nsViewManager.h
index d4df215c75b..82dde8f0f42 100644
--- a/mozilla/view/src/nsViewManager.h
+++ b/mozilla/view/src/nsViewManager.h
@@ -508,7 +508,8 @@ private:
   nsISupportsArray  *mCompositeListeners;
   nsCOMPtr<nsIFactory> mRegionFactory;
   nsView            *mRootView;
-  // mRootViewManager is a strong ref unless it equals |this|
+  // mRootViewManager is a strong ref unless it equals |this|.  It's
+  // never null (if we have no ancestors, it will be |this|).
   nsViewManager     *mRootViewManager;
   nsCOMPtr<nsIEventQueueService>  mEventQueueService;
   nsCOMPtr<nsIEventQueue>         mSynthMouseMoveEventQueue;