fix doctree leak

HTML like

<div>hello</div>
</body>
</html>
<div>hello</div>

currently causes the document tree to be a forest with
two root nodes.
To ensure we don't leak the first tree, an additional root node is
introduced to hold all document trees.

Catched by: Jeremy's valgrind logs
Reported by: corvid <corvid@lavabit.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/src/css.cc b/src/css.cc
index aa799002..e9a8eb56 100644
--- a/src/css.cc
+++ b/src/css.cc
@@ -150,7 +150,7 @@ bool CssSelector::match (Doctree *docTree, const DoctreeNode *node) {
                if (sel->match (node))
                   break;
 
-               node = node->parent;
+               node = docTree->parent (node);
             }
             break;
          default:
@@ -160,9 +160,9 @@ bool CssSelector::match (Doctree *docTree, const DoctreeNode *node) {
       comb = cs->combinator;
 
       if (comb == ADJACENT_SIBLING)
-         node = node->sibling;
+         node = docTree->sibling (node);
       else 
-         node = node->parent;
+         node = docTree->parent (node);
    }
 
    return true;