+struct tree_stack_entry {
+ struct tree_stack_entry *prev; /* Entry below this in the stack */
+ unsigned long lineno; /* Line number to restore */
+ char *name; /* Position of name in opt_path */
+};
+
+/* The top of the path stack. */
+static struct tree_stack_entry *tree_stack = NULL;
+unsigned long tree_lineno = 0;
+
+static void
+pop_tree_stack_entry(void)
+{
+ struct tree_stack_entry *entry = tree_stack;
+
+ tree_lineno = entry->lineno;
+ entry->name[0] = 0;
+ tree_stack = entry->prev;
+ free(entry);
+}
+
+static void
+push_tree_stack_entry(char *name, unsigned long lineno)
+{
+ struct tree_stack_entry *entry = calloc(1, sizeof(*entry));
+ size_t pathlen = strlen(opt_path);
+
+ if (!entry)
+ return;
+
+ entry->prev = tree_stack;
+ entry->name = opt_path + pathlen;
+ tree_stack = entry;
+
+ if (!string_format_from(opt_path, &pathlen, "%s/", name)) {
+ pop_tree_stack_entry();
+ return;
+ }
+
+ /* Move the current line to the first tree entry. */
+ tree_lineno = 1;
+ entry->lineno = lineno;
+}
+