1 /*
2 * Copyright (C) 1984-2024 Mark Nudelman
3 *
4 * You may distribute under the terms of either the GNU General Public
5 * License or the Less License, as specified in the README file.
6 *
7 * For more information, see the README file.
8 */
9
10
11 #include "less.h"
12
13 #define WHITESP(c) ((c)==' ' || (c)=='\t')
14
15 #if TAGS
16
17 public constant char ztags[] = "tags";
18 public constant char *tags = ztags;
19
20 static int total;
21 static int curseq;
22
23 extern int linenums;
24 extern int sigs;
25 extern int ctldisp;
26
27 enum tag_result {
28 TAG_FOUND,
29 TAG_NOFILE,
30 TAG_NOTAG,
31 TAG_NOTYPE,
32 TAG_INTR
33 };
34
35 /*
36 * Tag type
37 */
38 enum {
39 T_CTAGS, /* 'tags': standard and extended format (ctags) */
40 T_CTAGS_X, /* stdin: cross reference format (ctags) */
41 T_GTAGS, /* 'GTAGS': function definition (global) */
42 T_GRTAGS, /* 'GRTAGS': function reference (global) */
43 T_GSYMS, /* 'GSYMS': other symbols (global) */
44 T_GPATH /* 'GPATH': path name (global) */
45 };
46
47 static enum tag_result findctag(constant char *tag);
48 static enum tag_result findgtag(constant char *tag, int type);
49 static constant char *nextgtag(void);
50 static constant char *prevgtag(void);
51 static POSITION ctagsearch(void);
52 static POSITION gtagsearch(void);
53 static int getentry(char *buf, constant char **tag, constant char **file, constant char **line);
54
55 /*
56 * The list of tags generated by the last findgtag() call.
57 *
58 * Use either pattern or line number.
59 * findgtag() always uses line number, so pattern is always NULL.
60 * findctag() uses either pattern (in which case line number is 0),
61 * or line number (in which case pattern is NULL).
62 */
63 struct taglist {
64 struct tag *tl_first;
65 struct tag *tl_last;
66 };
67 struct tag {
68 struct tag *next, *prev; /* List links */
69 char *tag_file; /* Source file containing the tag */
70 LINENUM tag_linenum; /* Appropriate line number in source file */
71 char *tag_pattern; /* Pattern used to find the tag */
72 lbool tag_endline; /* True if the pattern includes '$' */
73 };
74 #define TAG_END ((struct tag *) &taglist)
75 static struct taglist taglist = { TAG_END, TAG_END };
76 static struct tag *curtag;
77
78 #define TAG_INS(tp) \
79 (tp)->next = TAG_END; \
80 (tp)->prev = taglist.tl_last; \
81 taglist.tl_last->next = (tp); \
82 taglist.tl_last = (tp);
83
84 #define TAG_RM(tp) \
85 (tp)->next->prev = (tp)->prev; \
86 (tp)->prev->next = (tp)->next;
87
88 /*
89 * Delete tag structures.
90 */
cleantags(void)91 public void cleantags(void)
92 {
93 struct tag *tp;
94
95 /*
96 * Delete any existing tag list.
97 * {{ Ideally, we wouldn't do this until after we know that we
98 * can load some other tag information. }}
99 */
100 while ((tp = taglist.tl_first) != TAG_END)
101 {
102 TAG_RM(tp);
103 free(tp->tag_file);
104 free(tp->tag_pattern);
105 free(tp);
106 }
107 curtag = NULL;
108 total = curseq = 0;
109 }
110
111 /*
112 * Create a new tag entry.
113 */
maketagent(constant char * file,LINENUM linenum,constant char * pattern,lbool endline)114 static struct tag * maketagent(constant char *file, LINENUM linenum, constant char *pattern, lbool endline)
115 {
116 struct tag *tp;
117
118 tp = (struct tag *) ecalloc(sizeof(struct tag), 1);
119 tp->tag_file = (char *) ecalloc(strlen(file) + 1, sizeof(char));
120 strcpy(tp->tag_file, file);
121 tp->tag_linenum = linenum;
122 tp->tag_endline = endline;
123 if (pattern == NULL)
124 tp->tag_pattern = NULL;
125 else
126 {
127 tp->tag_pattern = (char *) ecalloc(strlen(pattern) + 1, sizeof(char));
128 strcpy(tp->tag_pattern, pattern);
129 }
130 return (tp);
131 }
132
133 /*
134 * Get tag mode.
135 */
gettagtype(void)136 public int gettagtype(void)
137 {
138 int f;
139
140 if (strcmp(tags, "GTAGS") == 0)
141 return T_GTAGS;
142 if (strcmp(tags, "GRTAGS") == 0)
143 return T_GRTAGS;
144 if (strcmp(tags, "GSYMS") == 0)
145 return T_GSYMS;
146 if (strcmp(tags, "GPATH") == 0)
147 return T_GPATH;
148 if (strcmp(tags, "-") == 0)
149 return T_CTAGS_X;
150 f = open(tags, OPEN_READ);
151 if (f >= 0)
152 {
153 close(f);
154 return T_CTAGS;
155 }
156 return T_GTAGS;
157 }
158
159 /*
160 * Find tags in tag file.
161 * Find a tag in the "tags" file.
162 * Sets "tag_file" to the name of the file containing the tag,
163 * and "tagpattern" to the search pattern which should be used
164 * to find the tag.
165 */
findtag(constant char * tag)166 public void findtag(constant char *tag)
167 {
168 int type = gettagtype();
169 enum tag_result result;
170
171 if (type == T_CTAGS)
172 result = findctag(tag);
173 else
174 result = findgtag(tag, type);
175 switch (result)
176 {
177 case TAG_FOUND:
178 case TAG_INTR:
179 break;
180 case TAG_NOFILE:
181 error("No tags file", NULL_PARG);
182 break;
183 case TAG_NOTAG:
184 error("No such tag in tags file", NULL_PARG);
185 break;
186 case TAG_NOTYPE:
187 error("unknown tag type", NULL_PARG);
188 break;
189 }
190 }
191
192 /*
193 * Search for a tag.
194 */
tagsearch(void)195 public POSITION tagsearch(void)
196 {
197 if (curtag == NULL)
198 return (NULL_POSITION); /* No gtags loaded! */
199 if (curtag->tag_linenum != 0)
200 return gtagsearch();
201 else
202 return ctagsearch();
203 }
204
205 /*
206 * Go to the next tag.
207 */
nexttag(int n)208 public constant char * nexttag(int n)
209 {
210 constant char *tagfile = (char *) NULL;
211
212 while (n-- > 0)
213 tagfile = nextgtag();
214 return tagfile;
215 }
216
217 /*
218 * Go to the previous tag.
219 */
prevtag(int n)220 public constant char * prevtag(int n)
221 {
222 constant char *tagfile = (char *) NULL;
223
224 while (n-- > 0)
225 tagfile = prevgtag();
226 return tagfile;
227 }
228
229 /*
230 * Return the total number of tags.
231 */
ntags(void)232 public int ntags(void)
233 {
234 return total;
235 }
236
237 /*
238 * Return the sequence number of current tag.
239 */
curr_tag(void)240 public int curr_tag(void)
241 {
242 return curseq;
243 }
244
245 /*****************************************************************************
246 * ctags
247 */
248
249 /*
250 * Find tags in the "tags" file.
251 * Sets curtag to the first tag entry.
252 */
findctag(constant char * tag)253 static enum tag_result findctag(constant char *tag)
254 {
255 char *p;
256 char *q;
257 FILE *f;
258 size_t taglen;
259 LINENUM taglinenum;
260 char *tagfile;
261 char *tagpattern;
262 lbool tagendline;
263 int search_char;
264 lbool err;
265 char tline[TAGLINE_SIZE];
266 struct tag *tp;
267
268 p = shell_unquote(tags);
269 f = fopen(p, "r");
270 free(p);
271 if (f == NULL)
272 return TAG_NOFILE;
273
274 cleantags();
275 total = 0;
276 taglen = strlen(tag);
277
278 /*
279 * Search the tags file for the desired tag.
280 */
281 while (fgets(tline, sizeof(tline), f) != NULL)
282 {
283 if (tline[0] == '!')
284 /* Skip header of extended format. */
285 continue;
286 if (strncmp(tag, tline, taglen) != 0 || !WHITESP(tline[taglen]))
287 continue;
288
289 /*
290 * Found it.
291 * The line contains the tag, the filename and the
292 * location in the file, separated by white space.
293 * The location is either a decimal line number,
294 * or a search pattern surrounded by a pair of delimiters.
295 * Parse the line and extract these parts.
296 */
297 tagpattern = NULL;
298
299 /*
300 * Skip over the whitespace after the tag name.
301 */
302 p = skipsp(tline+taglen);
303 if (*p == '\0')
304 /* File name is missing! */
305 continue;
306
307 /*
308 * Save the file name.
309 * Skip over the whitespace after the file name.
310 */
311 tagfile = p;
312 while (!WHITESP(*p) && *p != '\0')
313 p++;
314 *p++ = '\0';
315 p = skipsp(p);
316 if (*p == '\0')
317 /* Pattern is missing! */
318 continue;
319
320 /*
321 * First see if it is a line number.
322 */
323 tagendline = FALSE;
324 taglinenum = getnum(&p, 0, &err);
325 if (err)
326 {
327 /*
328 * No, it must be a pattern.
329 * Delete the initial "^" (if present) and
330 * the final "$" from the pattern.
331 * Delete any backslash in the pattern.
332 */
333 taglinenum = 0;
334 search_char = *p++;
335 if (*p == '^')
336 p++;
337 tagpattern = q = p;
338 while (*p != search_char && *p != '\0')
339 {
340 if (*p == '\\')
341 p++;
342 if (q != p)
343 {
344 *q++ = *p++;
345 } else
346 {
347 q++;
348 p++;
349 }
350 }
351 tagendline = (q[-1] == '$');
352 if (tagendline)
353 q--;
354 *q = '\0';
355 }
356 tp = maketagent(tagfile, taglinenum, tagpattern, tagendline);
357 TAG_INS(tp);
358 total++;
359 }
360 fclose(f);
361 if (total == 0)
362 return TAG_NOTAG;
363 curtag = taglist.tl_first;
364 curseq = 1;
365 return TAG_FOUND;
366 }
367
368 /*
369 * Edit current tagged file.
370 */
edit_tagfile(void)371 public int edit_tagfile(void)
372 {
373 if (curtag == NULL)
374 return (1);
375 return (edit(curtag->tag_file));
376 }
377
curtag_match(char constant * line,POSITION linepos)378 static int curtag_match(char constant *line, POSITION linepos)
379 {
380 /*
381 * Test the line to see if we have a match.
382 * Use strncmp because the pattern may be
383 * truncated (in the tags file) if it is too long.
384 * If tagendline is set, make sure we match all
385 * the way to end of line (no extra chars after the match).
386 */
387 size_t len = strlen(curtag->tag_pattern);
388 if (strncmp(curtag->tag_pattern, line, len) == 0 &&
389 (!curtag->tag_endline || line[len] == '\0' || line[len] == '\r'))
390 {
391 curtag->tag_linenum = find_linenum(linepos);
392 return 1;
393 }
394 return 0;
395 }
396
397 /*
398 * Search for a tag.
399 * This is a stripped-down version of search().
400 * We don't use search() for several reasons:
401 * - We don't want to blow away any search string we may have saved.
402 * - The various regular-expression functions (from different systems:
403 * regcmp vs. re_comp) behave differently in the presence of
404 * parentheses (which are almost always found in a tag).
405 */
ctagsearch(void)406 static POSITION ctagsearch(void)
407 {
408 POSITION pos, linepos;
409 LINENUM linenum;
410 size_t line_len;
411 constant char *line;
412 int found;
413
414 pos = ch_zero();
415 linenum = find_linenum(pos);
416
417 for (found = 0; !found;)
418 {
419 /*
420 * Get lines until we find a matching one or
421 * until we hit end-of-file.
422 */
423 if (ABORT_SIGS())
424 return (NULL_POSITION);
425
426 /*
427 * Read the next line, and save the
428 * starting position of that line in linepos.
429 */
430 linepos = pos;
431 pos = forw_raw_line(pos, &line, &line_len);
432 if (linenum != 0)
433 linenum++;
434
435 if (pos == NULL_POSITION)
436 {
437 /*
438 * We hit EOF without a match.
439 */
440 error("Tag not found", NULL_PARG);
441 return (NULL_POSITION);
442 }
443
444 /*
445 * If we're using line numbers, we might as well
446 * remember the information we have now (the position
447 * and line number of the current line).
448 */
449 if (linenums)
450 add_lnum(linenum, pos);
451
452 if (ctldisp != OPT_ONPLUS)
453 {
454 if (curtag_match(line, linepos))
455 found = 1;
456 } else
457 {
458 int cvt_ops = CVT_ANSI;
459 size_t cvt_len = cvt_length(line_len, cvt_ops);
460 int *chpos = cvt_alloc_chpos(cvt_len);
461 char *cline = (char *) ecalloc(1, cvt_len);
462 cvt_text(cline, line, chpos, &line_len, cvt_ops);
463 if (curtag_match(cline, linepos))
464 found = 1;
465 free(chpos);
466 free(cline);
467 }
468 }
469
470 return (linepos);
471 }
472
473 /*******************************************************************************
474 * gtags
475 */
476
477 /*
478 * Find tags in the GLOBAL's tag file.
479 * The findgtag() will try and load information about the requested tag.
480 * It does this by calling "global -x tag" and storing the parsed output
481 * for future use by gtagsearch().
482 * Sets curtag to the first tag entry.
483 */
findgtag(constant char * tag,int type)484 static enum tag_result findgtag(constant char *tag, int type)
485 {
486 char buf[1024];
487 FILE *fp;
488 struct tag *tp;
489
490 if (type != T_CTAGS_X && tag == NULL)
491 return TAG_NOFILE;
492
493 cleantags();
494 total = 0;
495
496 /*
497 * If type == T_CTAGS_X then read ctags's -x format from stdin
498 * else execute global(1) and read from it.
499 */
500 if (type == T_CTAGS_X)
501 {
502 fp = stdin;
503 /* Set tag default because we cannot read stdin again. */
504 tags = ztags;
505 } else
506 {
507 #if !HAVE_POPEN
508 return TAG_NOFILE;
509 #else
510 char *command;
511 char *flag;
512 char *qtag;
513 constant char *cmd = lgetenv("LESSGLOBALTAGS");
514
515 if (isnullenv(cmd))
516 return TAG_NOFILE;
517 /* Get suitable flag value for global(1). */
518 switch (type)
519 {
520 case T_GTAGS:
521 flag = "" ;
522 break;
523 case T_GRTAGS:
524 flag = "r";
525 break;
526 case T_GSYMS:
527 flag = "s";
528 break;
529 case T_GPATH:
530 flag = "P";
531 break;
532 default:
533 return TAG_NOTYPE;
534 }
535
536 /* Get our data from global(1). */
537 qtag = shell_quote(tag);
538 if (qtag == NULL)
539 qtag = save(tag);
540 command = (char *) ecalloc(strlen(cmd) + strlen(flag) +
541 strlen(qtag) + 5, sizeof(char));
542 sprintf(command, "%s -x%s %s", cmd, flag, qtag);
543 free(qtag);
544 fp = popen(command, "r");
545 free(command);
546 #endif
547 }
548 if (fp != NULL)
549 {
550 while (fgets(buf, sizeof(buf), fp))
551 {
552 constant char *name;
553 constant char *file;
554 constant char *line;
555 size_t len;
556
557 if (sigs)
558 {
559 #if HAVE_POPEN
560 if (fp != stdin)
561 pclose(fp);
562 #endif
563 return TAG_INTR;
564 }
565 len = strlen(buf);
566 if (len > 0 && buf[len-1] == '\n')
567 buf[len-1] = '\0';
568 else
569 {
570 int c;
571 do {
572 c = fgetc(fp);
573 } while (c != '\n' && c != EOF);
574 }
575
576 if (getentry(buf, &name, &file, &line))
577 {
578 /*
579 * Couldn't parse this line for some reason.
580 * We'll just pretend it never happened.
581 */
582 break;
583 }
584
585 /* Make new entry and add to list. */
586 tp = maketagent(file, (LINENUM) atoi(line), NULL, FALSE);
587 TAG_INS(tp);
588 total++;
589 }
590 if (fp != stdin)
591 {
592 if (pclose(fp))
593 {
594 curtag = NULL;
595 total = curseq = 0;
596 return TAG_NOFILE;
597 }
598 }
599 }
600
601 /* Check to see if we found anything. */
602 tp = taglist.tl_first;
603 if (tp == TAG_END)
604 return TAG_NOTAG;
605 curtag = tp;
606 curseq = 1;
607 return TAG_FOUND;
608 }
609
610 static int circular = 0; /* 1: circular tag structure */
611
612 /*
613 * Return the filename required for the next gtag in the queue that was setup
614 * by findgtag(). The next call to gtagsearch() will try to position at the
615 * appropriate tag.
616 */
nextgtag(void)617 static constant char * nextgtag(void)
618 {
619 struct tag *tp;
620
621 if (curtag == NULL)
622 /* No tag loaded */
623 return NULL;
624
625 tp = curtag->next;
626 if (tp == TAG_END)
627 {
628 if (!circular)
629 return NULL;
630 /* Wrapped around to the head of the queue */
631 curtag = taglist.tl_first;
632 curseq = 1;
633 } else
634 {
635 curtag = tp;
636 curseq++;
637 }
638 return (curtag->tag_file);
639 }
640
641 /*
642 * Return the filename required for the previous gtag in the queue that was
643 * setup by findgtat(). The next call to gtagsearch() will try to position
644 * at the appropriate tag.
645 */
prevgtag(void)646 static constant char * prevgtag(void)
647 {
648 struct tag *tp;
649
650 if (curtag == NULL)
651 /* No tag loaded */
652 return NULL;
653
654 tp = curtag->prev;
655 if (tp == TAG_END)
656 {
657 if (!circular)
658 return NULL;
659 /* Wrapped around to the tail of the queue */
660 curtag = taglist.tl_last;
661 curseq = total;
662 } else
663 {
664 curtag = tp;
665 curseq--;
666 }
667 return (curtag->tag_file);
668 }
669
670 /*
671 * Position the current file at at what is hopefully the tag that was chosen
672 * using either findtag() or one of nextgtag() and prevgtag(). Returns -1
673 * if it was unable to position at the tag, 0 if successful.
674 */
gtagsearch(void)675 static POSITION gtagsearch(void)
676 {
677 if (curtag == NULL)
678 return (NULL_POSITION); /* No gtags loaded! */
679 return (find_pos(curtag->tag_linenum));
680 }
681
682 /*
683 * The getentry() parses both standard and extended ctags -x format.
684 *
685 * [standard format]
686 * <tag> <lineno> <file> <image>
687 * +------------------------------------------------
688 * |main 30 main.c main(argc, argv)
689 * |func 21 subr.c func(arg)
690 *
691 * The following commands write this format.
692 * o Traditional Ctags with -x option
693 * o Global with -x option
694 * See <http://www.gnu.org/software/global/global.html>
695 *
696 * [extended format]
697 * <tag> <type> <lineno> <file> <image>
698 * +----------------------------------------------------------
699 * |main function 30 main.c main(argc, argv)
700 * |func function 21 subr.c func(arg)
701 *
702 * The following commands write this format.
703 * o Exuberant Ctags with -x option
704 * See <http://ctags.sourceforge.net>
705 *
706 * Returns 0 on success, -1 on error.
707 * The tag, file, and line will each be NUL-terminated pointers
708 * into buf.
709 */
getentry(char * buf,constant char ** tag,constant char ** file,constant char ** line)710 static int getentry(char *buf, constant char **tag, constant char **file, constant char **line)
711 {
712 char *p = buf;
713
714 for (*tag = p; *p && !IS_SPACE(*p); p++) /* tag name */
715 ;
716 if (*p == 0)
717 return (-1);
718 *p++ = 0;
719 for ( ; *p && IS_SPACE(*p); p++) /* (skip blanks) */
720 ;
721 if (*p == 0)
722 return (-1);
723 /*
724 * If the second part begin with other than digit,
725 * it is assumed tag type. Skip it.
726 */
727 if (!IS_DIGIT(*p))
728 {
729 for ( ; *p && !IS_SPACE(*p); p++) /* (skip tag type) */
730 ;
731 for (; *p && IS_SPACE(*p); p++) /* (skip blanks) */
732 ;
733 }
734 if (!IS_DIGIT(*p))
735 return (-1);
736 *line = p; /* line number */
737 for (*line = p; *p && !IS_SPACE(*p); p++)
738 ;
739 if (*p == 0)
740 return (-1);
741 *p++ = 0;
742 for ( ; *p && IS_SPACE(*p); p++) /* (skip blanks) */
743 ;
744 if (*p == 0)
745 return (-1);
746 *file = p; /* file name */
747 for (*file = p; *p && !IS_SPACE(*p); p++)
748 ;
749 if (*p == 0)
750 return (-1);
751 *p = 0;
752
753 /* value check */
754 if (strlen(*tag) && strlen(*line) && strlen(*file) && atoi(*line) > 0)
755 return (0);
756 return (-1);
757 }
758
759 #endif
760