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Avoid recursive calls in etags
* lib-src/etags.c (stack_entry): New struct. (push_node, pop_node, put_entry): New functions. (free_tree, add_node, invalidate_nodes, put_entries): Re-implement in a non-recursive way, to avoid stack overflow. (Bug#5847)
This commit is contained in:
Eli Zaretskii
parent
6f125aa3de
commit
6d8144a2ab
1 changed files with 227 additions and 65 deletions
292
lib-src/etags.c
292
lib-src/etags.c
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@ -2005,20 +2005,81 @@ pfnote (char *name, bool is_func, char *linestart, int linelen, int lno,
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add_node (np, &nodehead);
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}
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/*
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* Utility functions and data to avoid recursion.
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*/
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typedef struct stack_entry {
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node *np;
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struct stack_entry *next;
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} stkentry;
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static void
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push_node (node *np, stkentry **stack_top)
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{
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if (np)
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{
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stkentry *new = xnew (1, stkentry);
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new->np = np;
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new->next = *stack_top;
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*stack_top = new;
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}
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}
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static node *
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pop_node (stkentry **stack_top)
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{
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node *ret = NULL;
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if (*stack_top)
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{
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stkentry *old_start = *stack_top;
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ret = (*stack_top)->np;
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*stack_top = (*stack_top)->next;
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free (old_start);
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}
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return ret;
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}
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/*
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* free_tree ()
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* recurse on left children, iterate on right children.
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* emulate recursion on left children, iterate on right children.
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*/
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static void
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free_tree (register node *np)
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{
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stkentry *stack = NULL;
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while (np)
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{
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register node *node_right = np->right;
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free_tree (np->left);
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register node *node_right;
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/* Descent on left children. */
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while (np->left)
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{
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push_node (np, &stack);
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np = np->left;
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}
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/* Free node without left children. */
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node_right = np->right;
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free (np->name);
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free (np->regex);
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free (np);
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if (!node_right)
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{
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/* Backtrack to find a node with right children, while freeing nodes
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that don't have right children. */
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while (node_right == NULL && (np = pop_node (&stack)) != NULL)
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{
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node_right = np->right;
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free (np->name);
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free (np->regex);
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free (np);
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}
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}
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/* Free right children. */
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np = node_right;
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}
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}
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@ -2050,9 +2111,9 @@ free_fdesc (register fdesc *fdp)
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static void
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add_node (node *np, node **cur_node_p)
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{
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register int dif;
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register node *cur_node = *cur_node_p;
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node *cur_node = *cur_node_p;
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/* Make the first node. */
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if (cur_node == NULL)
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{
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*cur_node_p = np;
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@ -2074,51 +2135,77 @@ add_node (node *np, node **cur_node_p)
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last_node->right = np;
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last_node = np;
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}
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else if (cur_node->fdp == np->fdp)
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{
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/* Scanning the list we found the head of a sublist which is
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good for us. Let's scan this sublist. */
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add_node (np, &cur_node->right);
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}
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else
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/* The head of this sublist is not good for us. Let's try the
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next one. */
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add_node (np, &cur_node->left);
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{
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while (cur_node->fdp != np->fdp)
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{
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if (cur_node->left == NULL)
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break;
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/* The head of this sublist is not good for us. Let's try the
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next one. */
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cur_node = cur_node->left;
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}
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if (cur_node->left)
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{
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/* Scanning the list we found the head of a sublist which is
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good for us. Let's scan this sublist. */
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if (cur_node->right)
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{
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cur_node = cur_node->right;
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while (cur_node->right)
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cur_node = cur_node->right;
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}
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/* Make a new node in this sublist. */
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cur_node->right = np;
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}
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else
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{
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/* Make a new sublist. */
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cur_node->left = np;
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}
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last_node = np;
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}
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} /* if ETAGS mode */
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else
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{
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/* Ctags Mode */
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dif = strcmp (np->name, cur_node->name);
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register int dif;
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node **next_node = &cur_node;
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/*
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* If this tag name matches an existing one, then
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* do not add the node, but maybe print a warning.
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*/
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if (no_duplicates && !dif)
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while ((cur_node = *next_node) != NULL)
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{
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if (np->fdp == cur_node->fdp)
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dif = strcmp (np->name, cur_node->name);
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/*
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* If this tag name matches an existing one, then
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* do not add the node, but maybe print a warning.
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*/
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if (!dif && no_duplicates)
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{
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if (!no_warnings)
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if (np->fdp == cur_node->fdp)
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{
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fprintf (stderr, "Duplicate entry in file %s, line %d: %s\n",
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np->fdp->infname, lineno, np->name);
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fprintf (stderr, "Second entry ignored\n");
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if (!no_warnings)
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{
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fprintf (stderr,
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"Duplicate entry in file %s, line %d: %s\n",
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np->fdp->infname, lineno, np->name);
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fprintf (stderr, "Second entry ignored\n");
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}
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}
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else if (!cur_node->been_warned && !no_warnings)
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{
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fprintf
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(stderr,
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"Duplicate entry in files %s and %s: %s (Warning only)\n",
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np->fdp->infname, cur_node->fdp->infname, np->name);
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cur_node->been_warned = true;
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}
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return;
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}
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else if (!cur_node->been_warned && !no_warnings)
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{
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fprintf
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(stderr,
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"Duplicate entry in files %s and %s: %s (Warning only)\n",
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np->fdp->infname, cur_node->fdp->infname, np->name);
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cur_node->been_warned = true;
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}
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return;
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else
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next_node = dif < 0 ? &cur_node->left : &cur_node->right;
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}
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/* Actually add the node */
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add_node (np, dif < 0 ? &cur_node->left : &cur_node->right);
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*next_node = np;
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last_node = np;
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} /* if CTAGS mode */
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}
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@ -2131,31 +2218,65 @@ static void
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invalidate_nodes (fdesc *badfdp, node **npp)
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{
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node *np = *npp;
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stkentry *stack = NULL;
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if (np == NULL)
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return;
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if (CTAGS)
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{
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if (np->left != NULL)
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invalidate_nodes (badfdp, &np->left);
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if (np->fdp == badfdp)
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np->valid = false;
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if (np->right != NULL)
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invalidate_nodes (badfdp, &np->right);
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while (np)
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{
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/* Push all the left children on the stack. */
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while (np->left != NULL)
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{
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push_node (np->left, &stack);
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np = np->left;
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}
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/* Invalidate this node. */
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if (np->fdp == badfdp)
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np->valid = false;
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if (!np->right)
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{
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/* Pop nodes from stack, invalidating them, until we find one
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with a right child. */
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do {
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np = pop_node (&stack);
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if (np->fdp == badfdp)
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np->valid = false;
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} while (np && np->right == NULL);
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}
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/* Process the right child, if any. */
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if (np)
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np = np->right;
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}
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}
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else
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{
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assert (np->fdp != NULL);
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if (np->fdp == badfdp)
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node super_root, *np_parent;
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super_root.left = np;
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super_root.fdp = (fdesc *)-1;
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np = &super_root;
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while (np)
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{
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*npp = np->left; /* detach the sublist from the list */
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np->left = NULL; /* isolate it */
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free_tree (np); /* free it */
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invalidate_nodes (badfdp, npp);
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/* Descent on left children until node with BADFP. */
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while (np && np->fdp != badfdp)
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{
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assert (np->fdp != NULL);
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np_parent = np;
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np = np->left;
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}
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if (np)
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{
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np_parent->left = np->left; /* detach subtree from the tree */
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np->left = NULL; /* isolate it */
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free_tree (np); /* free it */
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np = np_parent->left; /* continue with rest of tree */
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}
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}
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else
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invalidate_nodes (badfdp, &np->left);
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*npp = super_root.left;
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}
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}
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@ -2200,20 +2321,13 @@ total_size_of_entries (register node *np)
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}
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static void
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put_entries (register node *np)
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put_entry (register node *np)
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{
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register char *sp;
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static fdesc *fdp = NULL;
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if (np == NULL)
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return;
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/* Output subentries that precede this one */
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if (CTAGS)
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put_entries (np->left);
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/* Output this entry */
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if (np->valid)
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if (np && np->valid)
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{
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if (!CTAGS)
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{
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@ -2277,11 +2391,59 @@ put_entries (register node *np)
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}
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}
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} /* if this node contains a valid tag */
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}
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/* Output subentries that follow this one */
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put_entries (np->right);
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if (!CTAGS)
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put_entries (np->left);
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static void
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put_entries (register node *np)
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{
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stkentry *stack = NULL;
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if (np == NULL)
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return;
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if (CTAGS)
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{
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while (np)
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{
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/* Stack subentries that precede this one. */
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while (np->left)
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{
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push_node (np, &stack);
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np = np->left;
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}
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/* Output this subentry. */
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put_entry (np);
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/* Stack subentries that follow this one. */
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if (!np->right)
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{
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/* Output subentries that precede the next one. */
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do {
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np = pop_node (&stack);
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put_entry (np);
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} while (np && np->right == NULL);
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}
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if (np)
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np = np->right;
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}
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}
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else
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{
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push_node (np, &stack);
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while ((np = pop_node (&stack)) != NULL)
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{
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/* Output this subentry. */
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put_entry (np);
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while (np->right)
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{
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/* Output subentries that follow this one. */
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put_entry (np->right);
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/* Stack subentries from the following files. */
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push_node (np->left, &stack);
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np = np->right;
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}
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push_node (np->left, &stack);
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}
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}
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}
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