contrib/less/tags.c

   1 /*
   2  * Copyright (C) 1984-2022  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 char ztags[] = "tags";
  18 public 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 LESSPARAMS((char *tag));
  48 static enum tag_result findgtag LESSPARAMS((char *tag, int type));
  49 static char *nextgtag(VOID_PARAM);
  50 static char *prevgtag(VOID_PARAM);
  51 static POSITION ctagsearch(VOID_PARAM);
  52 static POSITION gtagsearch(VOID_PARAM);
  53 static int getentry LESSPARAMS((char *buf, char **tag, char **file, 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         char 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  */
  91         public void
  92 cleantags(VOID_PARAM)
  93 {
  94         struct tag *tp;
  95
  96         /*
  97          * Delete any existing tag list.
  98          * {{ Ideally, we wouldn't do this until after we know that we
  99          *    can load some other tag information. }}
 100          */
 101         while ((tp = taglist.tl_first) != TAG_END)
 102         {
 103                 TAG_RM(tp);
 104                 free(tp->tag_file);
 105                 free(tp->tag_pattern);
 106                 free(tp);
 107         }
 108         curtag = NULL;
 109         total = curseq = 0;
 110 }
 111
 112 /*
 113  * Create a new tag entry.
 114  */
 115         static struct tag *
 116 maketagent(name, file, linenum, pattern, endline)
 117         char *name;
 118         char *file;
 119         LINENUM linenum;
 120         char *pattern;
 121         int endline;
 122 {
 123         struct tag *tp;
 124
 125         tp = (struct tag *) ecalloc(sizeof(struct tag), 1);
 126         tp->tag_file = (char *) ecalloc(strlen(file) + 1, sizeof(char));
 127         strcpy(tp->tag_file, file);
 128         tp->tag_linenum = linenum;
 129         tp->tag_endline = endline;
 130         if (pattern == NULL)
 131                 tp->tag_pattern = NULL;
 132         else
 133         {
 134                 tp->tag_pattern = (char *) ecalloc(strlen(pattern) + 1, sizeof(char));
 135                 strcpy(tp->tag_pattern, pattern);
 136         }
 137         return (tp);
 138 }
 139
 140 /*
 141  * Get tag mode.
 142  */
 143         public int
 144 gettagtype(VOID_PARAM)
 145 {
 146         int f;
 147
 148         if (strcmp(tags, "GTAGS") == 0)
 149                 return T_GTAGS;
 150         if (strcmp(tags, "GRTAGS") == 0)
 151                 return T_GRTAGS;
 152         if (strcmp(tags, "GSYMS") == 0)
 153                 return T_GSYMS;
 154         if (strcmp(tags, "GPATH") == 0)
 155                 return T_GPATH;
 156         if (strcmp(tags, "-") == 0)
 157                 return T_CTAGS_X;
 158         f = open(tags, OPEN_READ);
 159         if (f >= 0)
 160         {
 161                 close(f);
 162                 return T_CTAGS;
 163         }
 164         return T_GTAGS;
 165 }
 166
 167 /*
 168  * Find tags in tag file.
 169  * Find a tag in the "tags" file.
 170  * Sets "tag_file" to the name of the file containing the tag,
 171  * and "tagpattern" to the search pattern which should be used
 172  * to find the tag.
 173  */
 174         public void
 175 findtag(tag)
 176         char *tag;
 177 {
 178         int type = gettagtype();
 179         enum tag_result result;
 180
 181         if (type == T_CTAGS)
 182                 result = findctag(tag);
 183         else
 184                 result = findgtag(tag, type);
 185         switch (result)
 186         {
 187         case TAG_FOUND:
 188         case TAG_INTR:
 189                 break;
 190         case TAG_NOFILE:
 191                 error("No tags file", NULL_PARG);
 192                 break;
 193         case TAG_NOTAG:
 194                 error("No such tag in tags file", NULL_PARG);
 195                 break;
 196         case TAG_NOTYPE:
 197                 error("unknown tag type", NULL_PARG);
 198                 break;
 199         }
 200 }
 201
 202 /*
 203  * Search for a tag.
 204  */
 205         public POSITION
 206 tagsearch(VOID_PARAM)
 207 {
 208         if (curtag == NULL)
 209                 return (NULL_POSITION);  /* No gtags loaded! */
 210         if (curtag->tag_linenum != 0)
 211                 return gtagsearch();
 212         else
 213                 return ctagsearch();
 214 }
 215
 216 /*
 217  * Go to the next tag.
 218  */
 219         public char *
 220 nexttag(n)
 221         int n;
 222 {
 223         char *tagfile = (char *) NULL;
 224
 225         while (n-- > 0)
 226                 tagfile = nextgtag();
 227         return tagfile;
 228 }
 229
 230 /*
 231  * Go to the previous tag.
 232  */
 233         public char *
 234 prevtag(n)
 235         int n;
 236 {
 237         char *tagfile = (char *) NULL;
 238
 239         while (n-- > 0)
 240                 tagfile = prevgtag();
 241         return tagfile;
 242 }
 243
 244 /*
 245  * Return the total number of tags.
 246  */
 247         public int
 248 ntags(VOID_PARAM)
 249 {
 250         return total;
 251 }
 252
 253 /*
 254  * Return the sequence number of current tag.
 255  */
 256         public int
 257 curr_tag(VOID_PARAM)
 258 {
 259         return curseq;
 260 }
 261
 262 /*****************************************************************************
 263  * ctags
 264  */
 265
 266 /*
 267  * Find tags in the "tags" file.
 268  * Sets curtag to the first tag entry.
 269  */
 270         static enum tag_result
 271 findctag(tag)
 272         char *tag;
 273 {
 274         char *p;
 275         char *q;
 276         FILE *f;
 277         int taglen;
 278         LINENUM taglinenum;
 279         char *tagfile;
 280         char *tagpattern;
 281         int tagendline;
 282         int search_char;
 283         int err;
 284         char tline[TAGLINE_SIZE];
 285         struct tag *tp;
 286
 287         p = shell_unquote(tags);
 288         f = fopen(p, "r");
 289         free(p);
 290         if (f == NULL)
 291                 return TAG_NOFILE;
 292
 293         cleantags();
 294         total = 0;
 295         taglen = (int) strlen(tag);
 296
 297         /*
 298          * Search the tags file for the desired tag.
 299          */
 300         while (fgets(tline, sizeof(tline), f) != NULL)
 301         {
 302                 if (tline[0] == '!')
 303                         /* Skip header of extended format. */
 304                         continue;
 305                 if (strncmp(tag, tline, taglen) != 0 || !WHITESP(tline[taglen]))
 306                         continue;
 307
 308                 /*
 309                  * Found it.
 310                  * The line contains the tag, the filename and the
 311                  * location in the file, separated by white space.
 312                  * The location is either a decimal line number,
 313                  * or a search pattern surrounded by a pair of delimiters.
 314                  * Parse the line and extract these parts.
 315                  */
 316                 tagpattern = NULL;
 317
 318                 /*
 319                  * Skip over the whitespace after the tag name.
 320                  */
 321                 p = skipsp(tline+taglen);
 322                 if (*p == '\0')
 323                         /* File name is missing! */
 324                         continue;
 325
 326                 /*
 327                  * Save the file name.
 328                  * Skip over the whitespace after the file name.
 329                  */
 330                 tagfile = p;
 331                 while (!WHITESP(*p) && *p != '\0')
 332                         p++;
 333                 *p++ = '\0';
 334                 p = skipsp(p);
 335                 if (*p == '\0')
 336                         /* Pattern is missing! */
 337                         continue;
 338
 339                 /*
 340                  * First see if it is a line number.
 341                  */
 342                 tagendline = 0;
 343                 taglinenum = getnum(&p, 0, &err);
 344                 if (err)
 345                 {
 346                         /*
 347                          * No, it must be a pattern.
 348                          * Delete the initial "^" (if present) and
 349                          * the final "$" from the pattern.
 350                          * Delete any backslash in the pattern.
 351                          */
 352                         taglinenum = 0;
 353                         search_char = *p++;
 354                         if (*p == '^')
 355                                 p++;
 356                         tagpattern = q = p;
 357                         while (*p != search_char && *p != '\0')
 358                         {
 359                                 if (*p == '\\')
 360                                         p++;
 361                                 if (q != p)
 362                                 {
 363                                         *q++ = *p++;
 364                                 } else
 365                                 {
 366                                         q++;
 367                                         p++;
 368                                 }
 369                         }
 370                         tagendline = (q[-1] == '$');
 371                         if (tagendline)
 372                                 q--;
 373                         *q = '\0';
 374                 }
 375                 tp = maketagent(tag, tagfile, taglinenum, tagpattern, tagendline);
 376                 TAG_INS(tp);
 377                 total++;
 378         }
 379         fclose(f);
 380         if (total == 0)
 381                 return TAG_NOTAG;
 382         curtag = taglist.tl_first;
 383         curseq = 1;
 384         return TAG_FOUND;
 385 }
 386
 387 /*
 388  * Edit current tagged file.
 389  */
 390         public int
 391 edit_tagfile(VOID_PARAM)
 392 {
 393         if (curtag == NULL)
 394                 return (1);
 395         return (edit(curtag->tag_file));
 396 }
 397
 398         static int
 399 curtag_match(line, linepos)
 400         char constant *line;
 401         POSITION linepos;
 402 {
 403         /*
 404          * Test the line to see if we have a match.
 405          * Use strncmp because the pattern may be
 406          * truncated (in the tags file) if it is too long.
 407          * If tagendline is set, make sure we match all
 408          * the way to end of line (no extra chars after the match).
 409          */
 410         int len = (int) strlen(curtag->tag_pattern);
 411         if (strncmp(curtag->tag_pattern, line, len) == 0 &&
 412             (!curtag->tag_endline || line[len] == '\0' || line[len] == '\r'))
 413         {
 414                 curtag->tag_linenum = find_linenum(linepos);
 415                 return 1;
 416         }
 417         return 0;
 418 }
 419
 420 /*
 421  * Search for a tag.
 422  * This is a stripped-down version of search().
 423  * We don't use search() for several reasons:
 424  *   -  We don't want to blow away any search string we may have saved.
 425  *   -  The various regular-expression functions (from different systems:
 426  *      regcmp vs. re_comp) behave differently in the presence of
 427  *      parentheses (which are almost always found in a tag).
 428  */
 429         static POSITION
 430 ctagsearch(VOID_PARAM)
 431 {
 432         POSITION pos, linepos;
 433         LINENUM linenum;
 434         int line_len;
 435         char *line;
 436         int found;
 437
 438         pos = ch_zero();
 439         linenum = find_linenum(pos);
 440
 441         for (found = 0; !found;)
 442         {
 443                 /*
 444                  * Get lines until we find a matching one or
 445                  * until we hit end-of-file.
 446                  */
 447                 if (ABORT_SIGS())
 448                         return (NULL_POSITION);
 449
 450                 /*
 451                  * Read the next line, and save the
 452                  * starting position of that line in linepos.
 453                  */
 454                 linepos = pos;
 455                 pos = forw_raw_line(pos, &line, &line_len);
 456                 if (linenum != 0)
 457                         linenum++;
 458
 459                 if (pos == NULL_POSITION)
 460                 {
 461                         /*
 462                          * We hit EOF without a match.
 463                          */
 464                         error("Tag not found", NULL_PARG);
 465                         return (NULL_POSITION);
 466                 }
 467
 468                 /*
 469                  * If we're using line numbers, we might as well
 470                  * remember the information we have now (the position
 471                  * and line number of the current line).
 472                  */
 473                 if (linenums)
 474                         add_lnum(linenum, pos);
 475
 476                 if (ctldisp != OPT_ONPLUS)
 477                 {
 478                         if (curtag_match(line, linepos))
 479                                 found = 1;
 480                 } else
 481                 {
 482                         int cvt_ops = CVT_ANSI;
 483                         int cvt_len = cvt_length(line_len, cvt_ops);
 484                         int *chpos = cvt_alloc_chpos(cvt_len);
 485                         char *cline = (char *) ecalloc(1, cvt_len);
 486                         cvt_text(cline, line, chpos, &line_len, cvt_ops);
 487                         if (curtag_match(cline, linepos))
 488                                 found = 1;
 489                         free(chpos);
 490                         free(cline);
 491                 }
 492         }
 493
 494         return (linepos);
 495 }
 496
 497 /*******************************************************************************
 498  * gtags
 499  */
 500
 501 /*
 502  * Find tags in the GLOBAL's tag file.
 503  * The findgtag() will try and load information about the requested tag.
 504  * It does this by calling "global -x tag" and storing the parsed output
 505  * for future use by gtagsearch().
 506  * Sets curtag to the first tag entry.
 507  */
 508         static enum tag_result
 509 findgtag(tag, type)
 510         char *tag;              /* tag to load */
 511         int type;               /* tags type */
 512 {
 513         char buf[1024];
 514         FILE *fp;
 515         struct tag *tp;
 516
 517         if (type != T_CTAGS_X && tag == NULL)
 518                 return TAG_NOFILE;
 519
 520         cleantags();
 521         total = 0;
 522
 523         /*
 524          * If type == T_CTAGS_X then read ctags's -x format from stdin
 525          * else execute global(1) and read from it.
 526          */
 527         if (type == T_CTAGS_X)
 528         {
 529                 fp = stdin;
 530                 /* Set tag default because we cannot read stdin again. */
 531                 tags = ztags;
 532         } else
 533         {
 534 #if !HAVE_POPEN
 535                 return TAG_NOFILE;
 536 #else
 537                 char *command;
 538                 char *flag;
 539                 char *qtag;
 540                 char *cmd = lgetenv("LESSGLOBALTAGS");
 541
 542                 if (isnullenv(cmd))
 543                         return TAG_NOFILE;
 544                 /* Get suitable flag value for global(1). */
 545                 switch (type)
 546                 {
 547                 case T_GTAGS:
 548                         flag = "" ;
 549                         break;
 550                 case T_GRTAGS:
 551                         flag = "r";
 552                         break;
 553                 case T_GSYMS:
 554                         flag = "s";
 555                         break;
 556                 case T_GPATH:
 557                         flag = "P";
 558                         break;
 559                 default:
 560                         return TAG_NOTYPE;
 561                 }
 562
 563                 /* Get our data from global(1). */
 564                 qtag = shell_quote(tag);
 565                 if (qtag == NULL)
 566                         qtag = tag;
 567                 command = (char *) ecalloc(strlen(cmd) + strlen(flag) +
 568                                 strlen(qtag) + 5, sizeof(char));
 569                 sprintf(command, "%s -x%s %s", cmd, flag, qtag);
 570                 if (qtag != tag)
 571                         free(qtag);
 572                 fp = popen(command, "r");
 573                 free(command);
 574 #endif
 575         }
 576         if (fp != NULL)
 577         {
 578                 while (fgets(buf, sizeof(buf), fp))
 579                 {
 580                         char *name, *file, *line;
 581                         int len;
 582
 583                         if (sigs)
 584                         {
 585 #if HAVE_POPEN
 586                                 if (fp != stdin)
 587                                         pclose(fp);
 588 #endif
 589                                 return TAG_INTR;
 590                         }
 591                         len = (int) strlen(buf);
 592                         if (len > 0 && buf[len-1] == '\n')
 593                                 buf[len-1] = '\0';
 594                         else
 595                         {
 596                                 int c;
 597                                 do {
 598                                         c = fgetc(fp);
 599                                 } while (c != '\n' && c != EOF);
 600                         }
 601
 602                         if (getentry(buf, &name, &file, &line))
 603                         {
 604                                 /*
 605                                  * Couldn't parse this line for some reason.
 606                                  * We'll just pretend it never happened.
 607                                  */
 608                                 break;
 609                         }
 610
 611                         /* Make new entry and add to list. */
 612                         tp = maketagent(name, file, (LINENUM) atoi(line), NULL, 0);
 613                         TAG_INS(tp);
 614                         total++;
 615                 }
 616                 if (fp != stdin)
 617                 {
 618                         if (pclose(fp))
 619                         {
 620                                 curtag = NULL;
 621                                 total = curseq = 0;
 622                                 return TAG_NOFILE;
 623                         }
 624                 }
 625         }
 626
 627         /* Check to see if we found anything. */
 628         tp = taglist.tl_first;
 629         if (tp == TAG_END)
 630                 return TAG_NOTAG;
 631         curtag = tp;
 632         curseq = 1;
 633         return TAG_FOUND;
 634 }
 635
 636 static int circular = 0;        /* 1: circular tag structure */
 637
 638 /*
 639  * Return the filename required for the next gtag in the queue that was setup
 640  * by findgtag().  The next call to gtagsearch() will try to position at the
 641  * appropriate tag.
 642  */
 643         static char *
 644 nextgtag(VOID_PARAM)
 645 {
 646         struct tag *tp;
 647
 648         if (curtag == NULL)
 649                 /* No tag loaded */
 650                 return NULL;
 651
 652         tp = curtag->next;
 653         if (tp == TAG_END)
 654         {
 655                 if (!circular)
 656                         return NULL;
 657                 /* Wrapped around to the head of the queue */
 658                 curtag = taglist.tl_first;
 659                 curseq = 1;
 660         } else
 661         {
 662                 curtag = tp;
 663                 curseq++;
 664         }
 665         return (curtag->tag_file);
 666 }
 667
 668 /*
 669  * Return the filename required for the previous gtag in the queue that was
 670  * setup by findgtat().  The next call to gtagsearch() will try to position
 671  * at the appropriate tag.
 672  */
 673         static char *
 674 prevgtag(VOID_PARAM)
 675 {
 676         struct tag *tp;
 677
 678         if (curtag == NULL)
 679                 /* No tag loaded */
 680                 return NULL;
 681
 682         tp = curtag->prev;
 683         if (tp == TAG_END)
 684         {
 685                 if (!circular)
 686                         return NULL;
 687                 /* Wrapped around to the tail of the queue */
 688                 curtag = taglist.tl_last;
 689                 curseq = total;
 690         } else
 691         {
 692                 curtag = tp;
 693                 curseq--;
 694         }
 695         return (curtag->tag_file);
 696 }
 697
 698 /*
 699  * Position the current file at at what is hopefully the tag that was chosen
 700  * using either findtag() or one of nextgtag() and prevgtag().  Returns -1
 701  * if it was unable to position at the tag, 0 if successful.
 702  */
 703         static POSITION
 704 gtagsearch(VOID_PARAM)
 705 {
 706         if (curtag == NULL)
 707                 return (NULL_POSITION);  /* No gtags loaded! */
 708         return (find_pos(curtag->tag_linenum));
 709 }
 710
 711 /*
 712  * The getentry() parses both standard and extended ctags -x format.
 713  *
 714  * [standard format]
 715  * <tag>   <lineno>  <file>         <image>
 716  * +------------------------------------------------
 717  * |main     30      main.c         main(argc, argv)
 718  * |func     21      subr.c         func(arg)
 719  *
 720  * The following commands write this format.
 721  *      o Traditinal Ctags with -x option
 722  *      o Global with -x option
 723  *              See <http://www.gnu.org/software/global/global.html>
 724  *
 725  * [extended format]
 726  * <tag>   <type>  <lineno>   <file>        <image>
 727  * +----------------------------------------------------------
 728  * |main     function 30      main.c         main(argc, argv)
 729  * |func     function 21      subr.c         func(arg)
 730  *
 731  * The following commands write this format.
 732  *      o Exuberant Ctags with -x option
 733  *              See <http://ctags.sourceforge.net>
 734  *
 735  * Returns 0 on success, -1 on error.
 736  * The tag, file, and line will each be NUL-terminated pointers
 737  * into buf.
 738  */
 739         static int
 740 getentry(buf, tag, file, line)
 741         char *buf;      /* standard or extended ctags -x format data */
 742         char **tag;     /* name of the tag we actually found */
 743         char **file;    /* file in which to find this tag */
 744         char **line;    /* line number of file where this tag is found */
 745 {
 746         char *p = buf;
 747
 748         for (*tag = p;  *p && !IS_SPACE(*p);  p++)      /* tag name */
 749                 ;
 750         if (*p == 0)
 751                 return (-1);
 752         *p++ = 0;
 753         for ( ;  *p && IS_SPACE(*p);  p++)              /* (skip blanks) */
 754                 ;
 755         if (*p == 0)
 756                 return (-1);
 757         /*
 758          * If the second part begin with other than digit,
 759          * it is assumed tag type. Skip it.
 760          */
 761         if (!IS_DIGIT(*p))
 762         {
 763                 for ( ;  *p && !IS_SPACE(*p);  p++)     /* (skip tag type) */
 764                         ;
 765                 for (;  *p && IS_SPACE(*p);  p++)       /* (skip blanks) */
 766                         ;
 767         }
 768         if (!IS_DIGIT(*p))
 769                 return (-1);
 770         *line = p;                                      /* line number */
 771         for (*line = p;  *p && !IS_SPACE(*p);  p++)
 772                 ;
 773         if (*p == 0)
 774                 return (-1);
 775         *p++ = 0;
 776         for ( ; *p && IS_SPACE(*p);  p++)               /* (skip blanks) */
 777                 ;
 778         if (*p == 0)
 779                 return (-1);
 780         *file = p;                                      /* file name */
 781         for (*file = p;  *p && !IS_SPACE(*p);  p++)
 782                 ;
 783         if (*p == 0)
 784                 return (-1);
 785         *p = 0;
 786
 787         /* value check */
 788         if (strlen(*tag) && strlen(*line) && strlen(*file) && atoi(*line) > 0)
 789                 return (0);
 790         return (-1);
 791 }
 792
 793 #endif