From 51307aaffd455bc5ce7ad03fd5f0862aa53712a2 Mon Sep 17 00:00:00 2001
From: "attinasi%netscape.com" <attinasi%netscape.com>
Date: Tue, 26 Sep 2000 21:00:32 +0000
Subject: [PATCH] Checking for null before deref: b=55358 r=a=buster

---
 layout/base/nsCSSFrameConstructor.cpp         | 24 ++++++++++++++-----
 .../html/style/src/nsCSSFrameConstructor.cpp  | 24 ++++++++++++++-----
 2 files changed, 36 insertions(+), 12 deletions(-)

diff --git a/layout/base/nsCSSFrameConstructor.cpp b/layout/base/nsCSSFrameConstructor.cpp
index 246f941368e..ce10d7d9709 100644
--- a/layout/base/nsCSSFrameConstructor.cpp
+++ b/layout/base/nsCSSFrameConstructor.cpp
@@ -7965,9 +7965,15 @@ FindPreviousAnonymousSibling(nsIPresShell* aPresShell,
   
   nsCOMPtr<nsIDocument> doc;
   aContainer->GetDocument(*getter_AddRefs(doc));
-  nsCOMPtr<nsIDOMDocumentXBL> xblDoc(do_QueryInterface(doc));
-  nsCOMPtr<nsIDOMElement> elt(do_QueryInterface(aContainer));
-  xblDoc->GetAnonymousNodes(elt, getter_AddRefs(nodeList));
+  NS_ASSERTION(doc, "null document from content element in FindPreviousAnonymousSibling");
+  if (doc) {
+    nsCOMPtr<nsIDOMDocumentXBL> xblDoc(do_QueryInterface(doc));
+    NS_ASSERTION(xblDoc, "null xblDoc for content element in FindPreviousAnonymousSibling");
+    if (xblDoc) {
+      nsCOMPtr<nsIDOMElement> elt(do_QueryInterface(aContainer));
+      xblDoc->GetAnonymousNodes(elt, getter_AddRefs(nodeList));
+    }
+  }
   if (nodeList) {
     PRUint32 ctr,listLength;
     nsCOMPtr<nsIDOMNode> node;
@@ -8031,9 +8037,15 @@ FindNextAnonymousSibling(nsIPresShell* aPresShell,
   
   nsCOMPtr<nsIDocument> doc;
   aContainer->GetDocument(*getter_AddRefs(doc));
-  nsCOMPtr<nsIDOMDocumentXBL> xblDoc(do_QueryInterface(doc));
-  nsCOMPtr<nsIDOMElement> elt(do_QueryInterface(aContainer));
-  xblDoc->GetAnonymousNodes(elt, getter_AddRefs(nodeList));
+  NS_ASSERTION(doc, "null document from content element in FindNextAnonymousSibling");
+  if (doc) {
+    nsCOMPtr<nsIDOMDocumentXBL> xblDoc(do_QueryInterface(doc));
+    NS_ASSERTION(xblDoc, "null xblDoc for content element in FindNextAnonymousSibling");
+    if (xblDoc) {
+      nsCOMPtr<nsIDOMElement> elt(do_QueryInterface(aContainer));
+      xblDoc->GetAnonymousNodes(elt, getter_AddRefs(nodeList));
+    }
+  }
   if (nodeList) {
     PRUint32 ctr,listLength;
     nsCOMPtr<nsIDOMNode> node;
diff --git a/layout/html/style/src/nsCSSFrameConstructor.cpp b/layout/html/style/src/nsCSSFrameConstructor.cpp
index 246f941368e..ce10d7d9709 100644
--- a/layout/html/style/src/nsCSSFrameConstructor.cpp
+++ b/layout/html/style/src/nsCSSFrameConstructor.cpp
@@ -7965,9 +7965,15 @@ FindPreviousAnonymousSibling(nsIPresShell* aPresShell,
   
   nsCOMPtr<nsIDocument> doc;
   aContainer->GetDocument(*getter_AddRefs(doc));
-  nsCOMPtr<nsIDOMDocumentXBL> xblDoc(do_QueryInterface(doc));
-  nsCOMPtr<nsIDOMElement> elt(do_QueryInterface(aContainer));
-  xblDoc->GetAnonymousNodes(elt, getter_AddRefs(nodeList));
+  NS_ASSERTION(doc, "null document from content element in FindPreviousAnonymousSibling");
+  if (doc) {
+    nsCOMPtr<nsIDOMDocumentXBL> xblDoc(do_QueryInterface(doc));
+    NS_ASSERTION(xblDoc, "null xblDoc for content element in FindPreviousAnonymousSibling");
+    if (xblDoc) {
+      nsCOMPtr<nsIDOMElement> elt(do_QueryInterface(aContainer));
+      xblDoc->GetAnonymousNodes(elt, getter_AddRefs(nodeList));
+    }
+  }
   if (nodeList) {
     PRUint32 ctr,listLength;
     nsCOMPtr<nsIDOMNode> node;
@@ -8031,9 +8037,15 @@ FindNextAnonymousSibling(nsIPresShell* aPresShell,
   
   nsCOMPtr<nsIDocument> doc;
   aContainer->GetDocument(*getter_AddRefs(doc));
-  nsCOMPtr<nsIDOMDocumentXBL> xblDoc(do_QueryInterface(doc));
-  nsCOMPtr<nsIDOMElement> elt(do_QueryInterface(aContainer));
-  xblDoc->GetAnonymousNodes(elt, getter_AddRefs(nodeList));
+  NS_ASSERTION(doc, "null document from content element in FindNextAnonymousSibling");
+  if (doc) {
+    nsCOMPtr<nsIDOMDocumentXBL> xblDoc(do_QueryInterface(doc));
+    NS_ASSERTION(xblDoc, "null xblDoc for content element in FindNextAnonymousSibling");
+    if (xblDoc) {
+      nsCOMPtr<nsIDOMElement> elt(do_QueryInterface(aContainer));
+      xblDoc->GetAnonymousNodes(elt, getter_AddRefs(nodeList));
+    }
+  }
   if (nodeList) {
     PRUint32 ctr,listLength;
     nsCOMPtr<nsIDOMNode> node;