Fix FS#11829 - %?xx<....> Crashes on targets where the %xx feature ta…

…g isnt avilable. rather hacky fix though better than crashing.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@28890 a1c6a512-1295-4272-9138-f99709370657

lib/skin_parser/skin_parser.c

@@ -969,37 +969,55 @@ static int skin_parse_conditional(struct skin_element* element, const char** doc
     cursor = bookmark;
 #endif
     /* Parsing the children */
-    element->children = skin_alloc_children(children);
-    if (!element->children)
-        return 0;
-    element->children_count = children;
-
-    for(i = 0; i < children; i++)
+
+    /* Feature tags could end up having 0 children which breaks
+     * the render in dangerous ways. Minor hack, but insert an empty
+     * child.  (e.g %?xx<foo> when xx isnt available ) */
+    
+    if (children == 0)
     {
-        element->children[i] = skin_parse_code_as_arg(&cursor);
-        if (element->children[i] == NULL)
-            return 0;
-        skip_whitespace(&cursor);
+		const char* emptyline= "";
+		children = 1;
+		element->children = skin_alloc_children(children);
+		if (!element->children)
+			return 0;
+		element->children_count = children;
+		element->children[0] = skin_parse_code_as_arg(&emptyline);
+	}
+	else
+	{	
+		element->children = skin_alloc_children(children);
+		if (!element->children)
+			return 0;
+		element->children_count = children;
+
+		for(i = 0; i < children; i++)
+		{
+			element->children[i] = skin_parse_code_as_arg(&cursor);
+			if (element->children[i] == NULL)
+				return 0;
+			skip_whitespace(&cursor);
 #ifdef ROCKBOX
-        if ((element->tag->flags&FEATURE_TAG) && feature_available)
-            cursor = conditional_end;
+			if ((element->tag->flags&FEATURE_TAG) && feature_available)
+				cursor = conditional_end;
 #endif
 
-        if(i < children - 1 && *cursor != ENUMLISTSEPARATESYM)
-        {
-            skin_error(SEPARATOR_EXPECTED, cursor);
-            return 0;
-        }
-        else if(i == children - 1 && *cursor != ENUMLISTCLOSESYM)
-        {
-            skin_error(CLOSE_EXPECTED, cursor);
-            return 0;
-        }
-        else
-        {
-            cursor++;
-        }
-    }
+			if(i < children - 1 && *cursor != ENUMLISTSEPARATESYM)
+			{
+				skin_error(SEPARATOR_EXPECTED, cursor);
+				return 0;
+			}
+			else if(i == children - 1 && *cursor != ENUMLISTCLOSESYM)
+			{
+				skin_error(CLOSE_EXPECTED, cursor);
+				return 0;
+			}
+			else
+			{
+				cursor++;
+			}
+		}
+	}
     *document = cursor;
 
     return 1;