xml: Make accessors NULL-resistant. Add fz_xml_find functions.

Find the first sibling, next sibling or first child matching tag name.

1 files changed, 36 insertions, 9 deletions

diff --git a/source/fitz/xml.c b/source/fitz/xml.c
index 5cdaa673..0d370331 100644
--- a/source/fitz/xml.c
+++ b/source/fitz/xml.c
@@ -123,50 +123,77 @@ void fz_debug_xml(fz_xml *item, int level)
 
 fz_xml *fz_xml_prev(fz_xml *item)
 {
-	return item->prev;
+	return item ? item->prev : NULL;
 }
 
 fz_xml *fz_xml_next(fz_xml *item)
 {
-	return item->next;
+	return item ? item->next : NULL;
 }
 
 fz_xml *fz_xml_up(fz_xml *item)
 {
-	return item->up;
+	return item ? item->up : NULL;
 }
 
 fz_xml *fz_xml_down(fz_xml *item)
 {
-	return item->down;
+	return item ? item->down : NULL;
 }
 
 char *fz_xml_text(fz_xml *item)
 {
-	return item->text;
+	return item ? item->text : NULL;
 }
 
 char *fz_xml_tag(fz_xml *item)
 {
-	if (item->name[0])
-		return item->name;
-	return NULL;
+	return item && item->name[0] ? item->name : NULL;
 }
 
 int fz_xml_is_tag(fz_xml *item, const char *name)
 {
-	return item->name && !strcmp(item->name, name);
+	if (!item)
+		return 0;
+	return !strcmp(item->name, name);
 }
 
 char *fz_xml_att(fz_xml *item, const char *name)
 {
 	struct attribute *att;
+	if (!item)
+		return NULL;
 	for (att = item->atts; att; att = att->next)
 		if (!strcmp(att->name, name))
 			return att->value;
 	return NULL;
 }
 
+fz_xml *fz_xml_find(fz_xml *item, const char *tag)
+{
+	while (item)
+	{
+		if (!strcmp(item->name, tag))
+			return item;
+		item = item->next;
+	}
+	return NULL;
+}
+
+fz_xml *fz_xml_find_next(fz_xml *item, const char *tag)
+{
+	if (item)
+		item = item->next;
+	return fz_xml_find(item, tag);
+}
+
+fz_xml *fz_xml_find_down(fz_xml *item, const char *tag)
+{
+	if (item)
+		item = item->down;
+	return fz_xml_find(item, tag);
+}
+
 static void xml_free_attribute(fz_context *ctx, struct attribute *att)
 {
 	while (att) {