diff --git a/mozilla/rdf/src/nsRDFDataModel.cpp b/mozilla/rdf/src/nsRDFDataModel.cpp
index 3d60a905a09..f98c1fa33bb 100644
--- a/mozilla/rdf/src/nsRDFDataModel.cpp
+++ b/mozilla/rdf/src/nsRDFDataModel.cpp
@@ -1,4 +1,4 @@
-/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
  *
  * The contents of this file are subject to the Netscape Public License
  * Version 1.0 (the "NPL"); you may not use this file except in
diff --git a/mozilla/rdf/src/nsRDFDataModelItem.cpp b/mozilla/rdf/src/nsRDFDataModelItem.cpp
index 30d2e2914ba..ea7cf6941d6 100644
--- a/mozilla/rdf/src/nsRDFDataModelItem.cpp
+++ b/mozilla/rdf/src/nsRDFDataModelItem.cpp
@@ -20,6 +20,10 @@
 #include "nsRDFDataModelItem.h"
 #include "rdf-int.h"
 
+static NS_DEFINE_IID(kISupportsIID,    NS_ISUPPORTS_IID);
+static NS_DEFINE_IID(kIDMItemIID,      NS_IDMITEM_IID);
+static NS_DEFINE_IID(kIRDFResourceIID, NS_IDMITEM_IID);
+
 ////////////////////////////////////////////////////////////////////////
 
 nsRDFDataModelItem::nsRDFDataModelItem(nsRDFDataModel& model, RDF_Resource resource)
@@ -44,8 +48,27 @@ nsRDFDataModelItem::~nsRDFDataModelItem(void)
 NS_IMPL_ADDREF(nsRDFDataModelItem);
 NS_IMPL_RELEASE(nsRDFDataModelItem);
 
-static NS_DEFINE_IID(kIDMItemIID, NS_IDMITEM_IID);
-NS_IMPL_QUERY_INTERFACE(nsRDFDataModelItem, kIDMItemIID);
+NS_IMETHODIMP
+nsRDFDataModelItem::QueryInterface(const nsIID& iid, void** result)
+{
+    if (! result)
+        return NS_ERROR_NULL_POINTER;
+
+    *result = NULL;
+    if (iid.Equals(kIDMItemIID) ||
+        iid.Equals(kISupportsIID)) {
+        *result = static_cast<nsIDMItem*>(this);
+        AddRef();
+        return NS_OK;
+    }
+    else if (iid.Equals(kIRDFResourceIID)) {
+        *result = static_cast<nsIRDFResource*>(this);
+        AddRef();
+        return NS_OK;
+    }
+    return NS_ERROR_NO_INTERFACE;
+}
+
 
 ////////////////////////////////////////////////////////////////////////
 // nsIDMItem interface
@@ -120,7 +143,20 @@ nsRDFDataModelItem::GetIntPropertyValue(PRInt32& value, const nsString& itemProp
     return NS_ERROR_NOT_IMPLEMENTED;
 }
 
+
 ////////////////////////////////////////////////////////////////////////
+// nsIRDFResource interface
+
+NS_IMETHODIMP
+nsRDFDataModelItem::GetResource(RDF_Resource& resource /* out */) const
+{
+    resource = mResource;
+    return NS_OK;
+}
+
+
+////////////////////////////////////////////////////////////////////////
+// Implementation methods
 
 void
 nsRDFDataModelItem::InvalidateCachedSubtreeSize(void)
@@ -204,7 +240,7 @@ nsRDFDataModelItem::Open(void)
         // Arcs are outbound, that is, from a parent to it's
         // child. Find all targets whose source is "me".
         cursor = RDF_GetTargets(mDataModel.GetDB(),
-                                GetResource(),
+                                mResource,
                                 mDataModel.GetArcProperty(),
                                 RDF_RESOURCE_TYPE,
                                 PR_TRUE);
@@ -213,7 +249,7 @@ nsRDFDataModelItem::Open(void)
         // Arcs are inbound, that is, from a child to it's
         // parent. Find all sources whose target is "me".
         cursor = RDF_GetSources(mDataModel.GetDB(),
-                                GetResource(),
+                                mResource,
                                 mDataModel.GetArcProperty(),
                                 RDF_RESOURCE_TYPE,
                                 PR_TRUE);
diff --git a/mozilla/rdf/src/nsRDFDataModelItem.h b/mozilla/rdf/src/nsRDFDataModelItem.h
index 57dcca4ede6..fe6ba4b386f 100644
--- a/mozilla/rdf/src/nsRDFDataModelItem.h
+++ b/mozilla/rdf/src/nsRDFDataModelItem.h
@@ -21,13 +21,14 @@
 
 #include "rdf.h"
 #include "nsIDMItem.h"
+#include "nsIRDFResource.h"
 #include "nsVector.h"
 
 class nsRDFDataModel;
 
 ////////////////////////////////////////////////////////////////////////
 
-class nsRDFDataModelItem : public nsIDMItem {
+class nsRDFDataModelItem : public nsIDMItem, public nsIRDFResource {
 private:
     nsRDFDataModel&     mDataModel;
     RDF_Resource        mResource;
@@ -76,15 +77,17 @@ public:
     NS_IMETHOD GetIntPropertyValue(PRInt32& value, const nsString& itemProperty) const;
 
     ////////////////////////////////////////////////////////////////////////
+    // nsIRDFResource interface
+
+    NS_IMETHOD GetResource(RDF_Resource& resource /* out */) const;
+
+    ////////////////////////////////////////////////////////////////////////
+    // Implementation methods
     
     nsRDFDataModel& GetDataModel(void) const {
         return mDataModel;
     }
 
-    RDF_Resource GetResource(void) const {
-        return mResource;
-    }
-
     PRBool IsOpen(void) const {
         return mOpen;
     }
diff --git a/mozilla/rdf/src/nsRDFTreeColumn.cpp b/mozilla/rdf/src/nsRDFTreeColumn.cpp
index de6609f8f52..5772392042f 100644
--- a/mozilla/rdf/src/nsRDFTreeColumn.cpp
+++ b/mozilla/rdf/src/nsRDFTreeColumn.cpp
@@ -21,8 +21,10 @@
 #include "nsIDMWidget.h"
 #include "nsIDataModel.h"
 
-static NS_DEFINE_IID(kIDataModelIID, NS_IDATAMODEL_IID);
-static NS_DEFINE_IID(kITreeColumnIID, NS_ITREECOLUMN_IID);
+static NS_DEFINE_IID(kISupportsIID,    NS_ISUPPORTS_IID);
+static NS_DEFINE_IID(kIDataModelIID,   NS_IDATAMODEL_IID);
+static NS_DEFINE_IID(kITreeColumnIID,  NS_ITREECOLUMN_IID);
+static NS_DEFINE_IID(kIRDFResourceIID, NS_IRDFRESOURCE_IID);
 
 const PRUint32 nsRDFTreeColumn::kDefaultWidth = 64; // XXX
 
@@ -51,7 +53,27 @@ nsRDFTreeColumn::~nsRDFTreeColumn(void)
 
 NS_IMPL_ADDREF(nsRDFTreeColumn);
 NS_IMPL_RELEASE(nsRDFTreeColumn);
-NS_IMPL_QUERY_INTERFACE(nsRDFTreeColumn, kITreeColumnIID);
+
+NS_IMETHODIMP
+nsRDFTreeColumn::QueryInterface(const nsIID& iid, void** result)
+{
+    if (! result)
+        return NS_ERROR_NULL_POINTER;
+
+    *result = NULL;
+    if (iid.Equals(kITreeColumnIID) ||
+        iid.Equals(kISupportsIID)) {
+        *result = static_cast<nsITreeColumn*>(this);
+        AddRef();
+        return NS_OK;
+    }
+    else if (iid.Equals(kIRDFResourceIID)) {
+        *result = static_cast<nsIRDFResource*>(this);
+        AddRef();
+        return NS_OK;
+    }
+    return NS_ERROR_NO_INTERFACE;
+}
 
 
 ////////////////////////////////////////////////////////////////////////
@@ -98,6 +120,18 @@ nsRDFTreeColumn::SetPixelWidth(PRUint32 newWidth)
 
 
 ////////////////////////////////////////////////////////////////////////
+// nsIRDFResource interface
+
+NS_IMETHODIMP
+nsRDFTreeColumn::GetResource(RDF_Resource& result) const
+{
+    result = mProperty;
+    return NS_OK;
+}
+
+
+////////////////////////////////////////////////////////////////////////
+// Implementation methods
 
 void
 nsRDFTreeColumn::SetVisibility(PRBool visible)
diff --git a/mozilla/rdf/src/nsRDFTreeColumn.h b/mozilla/rdf/src/nsRDFTreeColumn.h
index 9f4be76e6ee..0748e1d86f9 100644
--- a/mozilla/rdf/src/nsRDFTreeColumn.h
+++ b/mozilla/rdf/src/nsRDFTreeColumn.h
@@ -21,11 +21,12 @@
 
 #include "nsString.h"
 #include "nsITreeColumn.h"
+#include "nsIRDFResource.h"
 #include "rdf.h"
 
 class nsRDFTreeDataModel;
 
-class nsRDFTreeColumn : public nsITreeColumn {
+class nsRDFTreeColumn : public nsITreeColumn, public nsIRDFResource {
 private:
     nsRDFTreeDataModel& mTree;
     nsString            mName;
@@ -63,14 +64,16 @@ public:
     NS_IMETHOD SetPixelWidth(PRUint32 newWidth);
 
     ////////////////////////////////////////////////////////////////////////
+    // nsIRDFResource interface
+
+    NS_IMETHOD GetResource(RDF_Resource& result /* out */) const;
+
+    ////////////////////////////////////////////////////////////////////////
+    // Implementation methods
 
     void SetVisibility(PRBool visible);
 
     PRBool IsVisible(void) const;
-
-    RDF_Resource GetProperty(void) const {
-        return mProperty;
-    }
 };
 
 #endif // nsRDFTreeColumn_h__
diff --git a/mozilla/rdf/src/nsRDFTreeDataModel.cpp b/mozilla/rdf/src/nsRDFTreeDataModel.cpp
index 8902aba1d5f..041a57e9bd6 100644
--- a/mozilla/rdf/src/nsRDFTreeDataModel.cpp
+++ b/mozilla/rdf/src/nsRDFTreeDataModel.cpp
@@ -21,9 +21,10 @@
 #include "nsRDFTreeDataModelItem.h"
 #include "rdf-int.h"
 
-static NS_DEFINE_IID(kISupportsIID, NS_ISUPPORTS_IID);
-static NS_DEFINE_IID(kIDataModelIID, NS_IDATAMODEL_IID);
+static NS_DEFINE_IID(kISupportsIID,      NS_ISUPPORTS_IID);
+static NS_DEFINE_IID(kIDataModelIID,     NS_IDATAMODEL_IID);
 static NS_DEFINE_IID(kITreeDataModelIID, NS_ITREEDATAMODEL_IID);
+static NS_DEFINE_IID(kIRDFResourceIID,   NS_IRDFRESOURCE_IID);
 
 
 ////////////////////////////////////////////////////////////////////////
@@ -80,7 +81,11 @@ nsRDFTreeDataModel::QueryInterface(const nsIID& iid, void** result)
 NS_IMETHODIMP
 nsRDFTreeDataModel::InitFromURL(const nsString& url)
 {
-    return nsRDFDataModel::InitFromURL(url);
+    nsresult res = nsRDFDataModel::InitFromURL(url);
+    if (NS_SUCCEEDED(res))
+        res = CreateColumns();
+
+    return res;
 }
 
 
@@ -170,12 +175,6 @@ nsRDFTreeDataModel::GetNthTreeItem(nsITreeDMItem*& pItem, PRUint32 n) const
     return NS_ERROR_NOT_IMPLEMENTED;
 }
 
-#ifdef DYNAMIC_CASTING
-#define DYNAMIC_CAST(__type, __pointer) dynamic_cast<__type>(__pointer)
-#else
-#define DYNAMIC_CAST(__type, __pointer) ((__type)(__pointer))
-#endif
-
 NS_IMETHODIMP
 nsRDFTreeDataModel::GetItemTextForColumn(nsString& nodeText,
                                          nsITreeDMItem* pItem,
@@ -185,34 +184,60 @@ nsRDFTreeDataModel::GetItemTextForColumn(nsString& nodeText,
     // HT_GetNodeData() does. Hopefully it's enough to do the job for
     // now.
 
-    // XXX may need to turn off the dynamic_cast stuff...
-    nsRDFTreeDataModelItem* item =
-        DYNAMIC_CAST(nsRDFTreeDataModelItem*, pItem);
+    nsresult res = NS_OK;
+    nsIRDFResource* itemRsrc = NULL;
+    nsIRDFResource* columnRsrc = NULL;
 
-    PR_ASSERT(item);
-    if (! item)
-        return NS_ERROR_UNEXPECTED; // XXX
+    do {
+        if (NS_FAILED(pItem->QueryInterface(kIRDFResourceIID, (void**) &itemRsrc))) {
+            res = NS_ERROR_INVALID_ARG;
+            PR_ASSERT(0);
+            break;
+        }
 
-    nsRDFTreeColumn* column =
-        DYNAMIC_CAST(nsRDFTreeColumn*, pColumn);
+        if (NS_FAILED(pColumn->QueryInterface(kIRDFResourceIID, (void**) &columnRsrc))) {
+            res = NS_ERROR_INVALID_ARG;
+            PR_ASSERT(0);
+            break;
+        }
 
-    PR_ASSERT(column);
-    if (! column)
-        return NS_ERROR_UNEXPECTED; // XXX
+        RDF_Resource item;
+        if (NS_FAILED(itemRsrc->GetResource(item))) {
+            res = NS_ERROR_UNEXPECTED;
+            PR_ASSERT(0);
+            break;
+        }
+
+        RDF_Resource property;
+        if (NS_FAILED(columnRsrc->GetResource(property))) {
+            res = NS_ERROR_UNEXPECTED;
+            PR_ASSERT(0);
+            break;
+        }
     
-    const char* result =
-        (const char*) RDF_GetSlotValue(GetDB(),
-                                       item->GetResource(),   // resource
-                                       column->GetProperty(), // property
-                                       RDF_STRING_TYPE,
-                                       PR_FALSE,
-                                       PR_TRUE);
+        const char* result =
+            (const char*) RDF_GetSlotValue(GetDB(),
+                                           item,
+                                           property, // property
+                                           RDF_STRING_TYPE,
+                                           PR_FALSE,
+                                           PR_TRUE);
 
-    PR_ASSERT(result);
-    if (! result)
-        return NS_ERROR_NULL_POINTER;
+        if (! result) {
+            res = NS_ERROR_UNEXPECTED;
+            PR_ASSERT(0);
+            break;
+        }
+
+        nodeText = result;
+    } while (0);
+
+    if (columnRsrc)
+        columnRsrc->Release();
+
+    if (itemRsrc)
+        itemRsrc->Release();
 
-    nodeText = result;
     return NS_OK;
 }
 
@@ -220,23 +245,27 @@ nsRDFTreeDataModel::GetItemTextForColumn(nsString& nodeText,
 ////////////////////////////////////////////////////////////////////////
 // nsRDFTreeDataModel implementation methods
 
-void
+nsresult
 nsRDFTreeDataModel::CreateColumns(void)
 {
     // This mostly came over from HT_NewView()
     nsRDFDataModelItem* root = GetRoot();
     PR_ASSERT(root);
     if (! root)
-        return;
+        return NS_ERROR_NULL_POINTER; // XXX need something better here
+
+    RDF_Resource rootResource;
+    if (NS_FAILED(root->GetResource(rootResource)))
+        return NS_ERROR_UNEXPECTED;
 
     RDF_Cursor cursor;
-    cursor = RDF_GetTargets(GetDB(), root->GetResource(),
+    cursor = RDF_GetTargets(GetDB(), rootResource,
                             gNavCenter->RDF_Column,
                             RDF_RESOURCE_TYPE, PR_TRUE);
 
     PR_ASSERT(cursor != NULL);
     if (cursor == NULL)
-        return;
+        return NS_ERROR_UNEXPECTED; // XXX need something better here
 
     RDF_Resource r;
     while ((r = static_cast<RDF_Resource>(RDF_NextValue(cursor))) != NULL) {
@@ -270,6 +299,8 @@ nsRDFTreeDataModel::CreateColumns(void)
         mColumns.Add(column);
     }	
     RDF_DisposeCursor(cursor);
+
+    return NS_OK;
 }
 
 void
diff --git a/mozilla/rdf/src/nsRDFTreeDataModel.h b/mozilla/rdf/src/nsRDFTreeDataModel.h
index 3dd27eb6dfc..d76995a13bd 100644
--- a/mozilla/rdf/src/nsRDFTreeDataModel.h
+++ b/mozilla/rdf/src/nsRDFTreeDataModel.h
@@ -84,7 +84,7 @@ public:
 private:
     nsVector       mColumns;
 
-    void CreateColumns(void);
+    nsresult CreateColumns(void);
 };