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File: [cvsweb.bsd.lv] / mandoc / tag.c (download)

Revision 1.37, Tue Apr 26 11:38:38 2022 UTC (23 months ago) by schwarze
Branch: MAIN
Changes since 1.36: +17 -4 lines

If a node is tagged explicitly, skip implicit tagging for that node.
Apart from making sense in the first place, this fixes an assertion
failure that happened when the calculated implicit tag did not match
the string value of the first child of the node,

Bug found by tb@ using afl(1).

/* $Id: tag.c,v 1.37 2022/04/26 11:38:38 schwarze Exp $ */
/*
 * Copyright (c) 2015, 2016, 2018, 2019, 2020, 2022
 *               Ingo Schwarze <schwarze@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 * Functions to tag syntax tree nodes.
 * For internal use by mandoc(1) validation modules only.
 */
#include "config.h"

#include <sys/types.h>

#include <assert.h>
#include <limits.h>
#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>

#include "mandoc_aux.h"
#include "mandoc_ohash.h"
#include "roff.h"
#include "mdoc.h"
#include "roff_int.h"
#include "tag.h"

struct tag_entry {
	struct roff_node **nodes;
	size_t	 maxnodes;
	size_t	 nnodes;
	int	 prio;
	char	 s[];
};

static void		 tag_move_href(struct roff_man *,
				struct roff_node *, const char *);
static void		 tag_move_id(struct roff_node *);

static struct ohash	 tag_data;


/*
 * Set up the ohash table to collect nodes
 * where various marked-up terms are documented.
 */
void
tag_alloc(void)
{
	mandoc_ohash_init(&tag_data, 4, offsetof(struct tag_entry, s));
}

void
tag_free(void)
{
	struct tag_entry	*entry;
	unsigned int		 slot;

	if (tag_data.info.free == NULL)
		return;
	entry = ohash_first(&tag_data, &slot);
	while (entry != NULL) {
		free(entry->nodes);
		free(entry);
		entry = ohash_next(&tag_data, &slot);
	}
	ohash_delete(&tag_data);
	tag_data.info.free = NULL;
}

/*
 * Set a node where a term is defined,
 * unless the term is already defined at a lower priority.
 */
void
tag_put(const char *s, int prio, struct roff_node *n)
{
	struct tag_entry	*entry;
	struct roff_node	*nold;
	const char		*se;
	size_t			 len;
	unsigned int		 slot;

	assert(prio <= TAG_FALLBACK);

	/*
	 * If the node is already tagged, the existing tag is
	 * explicit and we are now about to add an implicit tag.
	 * Don't do that; just skip implicit tagging if the author
	 * specified an explicit tag.
	 */

	if (n->flags & NODE_ID)
		return;

	/* Determine the implicit tag. */

	if (s == NULL) {
		if (n->child == NULL || n->child->type != ROFFT_TEXT)
			return;
		s = n->child->string;
		switch (s[0]) {
		case '-':
			s++;
			break;
		case '\\':
			switch (s[1]) {
			case '&':
			case '-':
			case 'e':
				s += 2;
				break;
			default:
				break;
			}
			break;
		default:
			break;
		}
	}

	/*
	 * Skip whitespace and escapes and whatever follows,
	 * and if there is any, downgrade the priority.
	 */

	len = strcspn(s, " \t\\");
	if (len == 0)
		return;

	se = s + len;
	if (*se != '\0' && prio < TAG_WEAK)
		prio = TAG_WEAK;

	slot = ohash_qlookupi(&tag_data, s, &se);
	entry = ohash_find(&tag_data, slot);

	/* Build a new entry. */

	if (entry == NULL) {
		entry = mandoc_malloc(sizeof(*entry) + len + 1);
		memcpy(entry->s, s, len);
		entry->s[len] = '\0';
		entry->nodes = NULL;
		entry->maxnodes = entry->nnodes = 0;
		ohash_insert(&tag_data, slot, entry);
	}

	/*
	 * Lower priority numbers take precedence.
	 * If a better entry is already present, ignore the new one.
	 */

	else if (entry->prio < prio)
		return;

	/*
	 * If the existing entry is worse, clear it.
	 * In addition, a tag with priority TAG_FALLBACK
	 * is only used if the tag occurs exactly once.
	 */

	else if (entry->prio > prio || prio == TAG_FALLBACK) {
		while (entry->nnodes > 0) {
			nold = entry->nodes[--entry->nnodes];
			nold->flags &= ~NODE_ID;
			free(nold->tag);
			nold->tag = NULL;
		}
		if (prio == TAG_FALLBACK) {
			entry->prio = TAG_DELETE;
			return;
		}
	}

	/* Remember the new node. */

	if (entry->maxnodes == entry->nnodes) {
		entry->maxnodes += 4;
		entry->nodes = mandoc_reallocarray(entry->nodes,
		    entry->maxnodes, sizeof(*entry->nodes));
	}
	entry->nodes[entry->nnodes++] = n;
	entry->prio = prio;
	n->flags |= NODE_ID;
	if (n->child == NULL || n->child->string != s || *se != '\0') {
		assert(n->tag == NULL);
		n->tag = mandoc_strndup(s, len);
	}
}

int
tag_exists(const char *tag)
{
	return ohash_find(&tag_data, ohash_qlookup(&tag_data, tag)) != NULL;
}

/*
 * For in-line elements, move the link target
 * to the enclosing paragraph when appropriate.
 */
static void
tag_move_id(struct roff_node *n)
{
	struct roff_node *np;

	np = n;
	for (;;) {
		if (np->prev != NULL)
			np = np->prev;
		else if ((np = np->parent) == NULL)
			return;
		switch (np->tok) {
		case MDOC_It:
			switch (np->parent->parent->norm->Bl.type) {
			case LIST_column:
				/* Target the ROFFT_BLOCK = <tr>. */
				np = np->parent;
				break;
			case LIST_diag:
			case LIST_hang:
			case LIST_inset:
			case LIST_ohang:
			case LIST_tag:
				/* Target the ROFFT_HEAD = <dt>. */
				np = np->parent->head;
				break;
			default:
				/* Target the ROFF_BODY = <li>. */
				break;
			}
			/* FALLTHROUGH */
		case MDOC_Pp:	/* Target the ROFFT_ELEM = <p>. */
			if (np->tag == NULL) {
				np->tag = mandoc_strdup(n->tag == NULL ?
				    n->child->string : n->tag);
				np->flags |= NODE_ID;
				n->flags &= ~NODE_ID;
			}
			return;
		case MDOC_Sh:
		case MDOC_Ss:
		case MDOC_Bd:
		case MDOC_Bl:
		case MDOC_D1:
		case MDOC_Dl:
		case MDOC_Rs:
			/* Do not move past major blocks. */
			return;
		default:
			/*
			 * Move past in-line content and partial
			 * blocks, for example .It Xo or .It Bq Er.
			 */
			break;
		}
	}
}

/*
 * When a paragraph is tagged and starts with text,
 * move the permalink to the first few words.
 */
static void
tag_move_href(struct roff_man *man, struct roff_node *n, const char *tag)
{
	char	*cp;

	if (n == NULL || n->type != ROFFT_TEXT ||
	    *n->string == '\0' || *n->string == ' ')
		return;

	cp = n->string;
	while (cp != NULL && cp - n->string < 5)
		cp = strchr(cp + 1, ' ');

	/* If the first text node is longer, split it. */

	if (cp != NULL && cp[1] != '\0') {
		man->last = n;
		man->next = ROFF_NEXT_SIBLING;
		roff_word_alloc(man, n->line,
		    n->pos + (cp - n->string), cp + 1);
		man->last->flags = n->flags & ~NODE_LINE;
		*cp = '\0';
	}

	assert(n->tag == NULL);
	n->tag = mandoc_strdup(tag);
	n->flags |= NODE_HREF;
}

/*
 * When all tags have been set, decide where to put
 * the associated permalinks, and maybe move some tags
 * to the beginning of the respective paragraphs.
 */
void
tag_postprocess(struct roff_man *man, struct roff_node *n)
{
	if (n->flags & NODE_ID) {
		switch (n->tok) {
		case MDOC_Pp:
			tag_move_href(man, n->next, n->tag);
			break;
		case MDOC_Bd:
		case MDOC_D1:
		case MDOC_Dl:
			tag_move_href(man, n->child, n->tag);
			break;
		case MDOC_Bl:
			/* XXX No permalink for now. */
			break;
		default:
			if (n->type == ROFFT_ELEM || n->tok == MDOC_Fo)
				tag_move_id(n);
			if (n->tok != MDOC_Tg)
				n->flags |= NODE_HREF;
			else if ((n->flags & NODE_ID) == 0) {
				n->flags |= NODE_NOPRT;
				free(n->tag);
				n->tag = NULL;
			}
			break;
		}
	}
	for (n = n->child; n != NULL; n = n->next)
		tag_postprocess(man, n);
}