[libxml2] Pointer dereferenced before null check

[Daniel Veillard <veillard src gnome org>]

commit 91309d3a1d45aa70aa223b1e3ef1b23ab1c0cf36
Author: Daniel Veillard <veillard redhat com>
Date:   Mon Oct 6 20:07:19 2014 +0800

    Pointer dereferenced before null check
    
    For https://bugzilla.gnome.org/show_bug.cgi?id=707027
    
    A few pointer dereference before NULL check fixed.
    Removed a useless test

 xmlreader.c |   17 +++++++++++++----
 1 files changed, 13 insertions(+), 4 deletions(-)
---
diff --git a/xmlreader.c b/xmlreader.c
index 2607a70..f19e123 100644
--- a/xmlreader.c
+++ b/xmlreader.c
@@ -286,7 +286,10 @@ static void
 xmlTextReaderFreeProp(xmlTextReaderPtr reader, xmlAttrPtr cur) {
     xmlDictPtr dict;
 
-    dict = reader->ctxt->dict;
+    if ((reader != NULL) && (reader->ctxt != NULL))
+       dict = reader->ctxt->dict;
+    else
+        dict = NULL;
     if (cur == NULL) return;
 
     if ((__xmlRegisterCallbacks) && (xmlDeregisterNodeDefaultValue))
@@ -323,7 +326,7 @@ xmlTextReaderFreeProp(xmlTextReaderPtr reader, xmlAttrPtr cur) {
 static void
 xmlTextReaderFreePropList(xmlTextReaderPtr reader, xmlAttrPtr cur) {
     xmlAttrPtr next;
-    if (cur == NULL) return;
+
     while (cur != NULL) {
         next = cur->next;
         xmlTextReaderFreeProp(reader, cur);
@@ -344,7 +347,10 @@ xmlTextReaderFreeNodeList(xmlTextReaderPtr reader, xmlNodePtr cur) {
     xmlNodePtr next;
     xmlDictPtr dict;
 
-    dict = reader->ctxt->dict;
+    if ((reader != NULL) && (reader->ctxt != NULL))
+       dict = reader->ctxt->dict;
+    else
+        dict = NULL;
     if (cur == NULL) return;
     if (cur->type == XML_NAMESPACE_DECL) {
        xmlFreeNsList((xmlNsPtr) cur);
@@ -421,7 +427,10 @@ static void
 xmlTextReaderFreeNode(xmlTextReaderPtr reader, xmlNodePtr cur) {
     xmlDictPtr dict;
 
-    dict = reader->ctxt->dict;
+    if ((reader != NULL) && (reader->ctxt != NULL))
+       dict = reader->ctxt->dict;
+    else
+        dict = NULL;
     if (cur->type == XML_DTD_NODE) {
        xmlFreeDtd((xmlDtdPtr) cur);
        return;