part of fix for 122693 display problems when deleting messages in threaded view r/sr=sspitzer, a=sspitzer

mailnews/base/src/nsMsgThreadedDBView.cpp

@@ -571,6 +571,35 @@ nsresult nsMsgThreadedDBView::OnNewHeader(nsMsgKey newKey, nsMsgKey aParentKey,
   return rv;
 }
 
+
+NS_IMETHODIMP nsMsgThreadedDBView::OnParentChanged (nsMsgKey aKeyChanged, nsMsgKey oldParent, nsMsgKey newParent, nsIDBChangeListener *aInstigator)
+{
+  // we need to adjust the level of the hdr whose parent changed, and invalidate that row,
+  // iff we're in threaded mode.
+  if (m_viewFlags & nsMsgViewFlagsType::kThreadedDisplay)
+  {
+    nsMsgViewIndex parentIndex = FindViewIndex(newParent);
+    if (parentIndex != nsMsgViewIndex_None)
+    {
+      nsMsgViewIndex childIndex = FindViewIndex(aKeyChanged);
+      if (childIndex != nsMsgViewIndex_None)
+      {
+        PRInt32 levelChanged = m_levels[childIndex];
+        m_levels[childIndex] = m_levels[parentIndex] + 1;
+        for (nsMsgViewIndex viewIndex = childIndex + 1; viewIndex < GetSize() && m_levels[viewIndex] > levelChanged;  viewIndex++)
+        {
+          m_levels[viewIndex] = m_levels[viewIndex] - 1;
+          NoteChange(viewIndex, 1, nsMsgViewNotificationCode::changed);
+        }
+        NoteChange(childIndex, 1, nsMsgViewNotificationCode::changed);
+      }
+    }
+
+  }
+  return NS_OK;
+}
+
+
 nsMsgViewIndex nsMsgThreadedDBView::GetInsertInfoForNewHdr(nsIMsgDBHdr *newHdr, nsMsgViewIndex parentIndex, PRInt32 targetLevel)
 {
   PRInt32 viewSize = GetSize();

mailnews/base/src/nsMsgThreadedDBView.h

@@ -57,6 +57,8 @@ public:
   NS_IMETHOD GetViewType(nsMsgViewTypeValue *aViewType);
   NS_IMETHOD GetSupportsThreading(PRBool *aResult);
 
+	NS_IMETHOD OnParentChanged (nsMsgKey aKeyChanged, nsMsgKey oldParent, nsMsgKey newParent, nsIDBChangeListener *aInstigator);
+
 protected:
   virtual const char * GetViewName(void) {return "ThreadedDBView"; }
   nsresult InitThreadedView(PRInt32 *pCount);

mailnews/db/msgdb/src/nsMsgThread.cpp

@@ -578,10 +578,8 @@ nsresult nsMsgThread::ReparentChildrenOf(nsMsgKey oldParent, nsMsgKey newParent,
           
           curHdr->SetThreadParent(newParent);
           curHdr->GetMessageKey(&curKey);
-#ifdef NEEDED // I don't think we care anymore
           if (announcer)
             announcer->NotifyParentChangedAll(curKey, oldParent, newParent, nsnull);
-#endif
           // if the old parent was the root of the thread, then only the first child gets 
           // promoted to root, and other children become children of the new root.
           if (newParent == nsMsgKey_None)