Guarding against freeing NULL pointers.

src/node.c

@@ -65,6 +65,7 @@ node * r3_tree_create(int cap) {
 }
 
 void r3_tree_free(node * tree) {
+    if (tree) {
         for (int i = 0 ; i < tree->edge_len ; i++ ) {
             if (tree->edges[i]) {
                 r3_edge_free(tree->edges[ i ]);
@@ -85,6 +86,7 @@ void r3_tree_free(node * tree) {
         zfree(tree);
         tree = NULL;
     }
+}
 
 
 
@@ -237,9 +239,11 @@ match_entry * match_entry_createl(char * path, int path_len) {
 }
 
 void match_entry_free(match_entry * entry) {
+    if (entry) {
         str_array_free(entry->vars);
         zfree(entry);
     }
+}
 
 
 
@@ -385,8 +389,10 @@ route * r3_route_create(char * path) {
 }
 
 void r3_route_free(route * route) {
+    if (route) {
         zfree(route);
     }
+}
 
 route * r3_route_createl(char * path, int path_len) {
     route * info = zmalloc(sizeof(route));