contrib/less/tags.c

   1 /*
   2  * Copyright (C) 1984-2012  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 *tags = "tags";
  18
  19 static int total;
  20 static int curseq;
  21
  22 extern int linenums;
  23 extern int sigs;
  24
  25 enum tag_result {
  26         TAG_FOUND,
  27         TAG_NOFILE,
  28         TAG_NOTAG,
  29         TAG_NOTYPE,
  30         TAG_INTR
  31 };
  32
  33 /*
  34  * Tag type
  35  */
  36 enum {
  37         T_CTAGS,        /* 'tags': standard and extended format (ctags) */
  38         T_CTAGS_X,      /* stdin: cross reference format (ctags) */
  39         T_GTAGS,        /* 'GTAGS': function defenition (global) */
  40         T_GRTAGS,       /* 'GRTAGS': function reference (global) */
  41         T_GSYMS,        /* 'GSYMS': other symbols (global) */
  42         T_GPATH         /* 'GPATH': path name (global) */
  43 };
  44
  45 static enum tag_result findctag();
  46 static enum tag_result findgtag();
  47 static char *nextgtag();
  48 static char *prevgtag();
  49 static POSITION ctagsearch();
  50 static POSITION gtagsearch();
  51 static int getentry();
  52
  53 /*
  54  * The list of tags generated by the last findgtag() call.
  55  *
  56  * Use either pattern or line number.
  57  * findgtag() always uses line number, so pattern is always NULL.
  58  * findctag() uses either pattern (in which case line number is 0),
  59  * or line number (in which case pattern is NULL).
  60  */
  61 struct taglist {
  62         struct tag *tl_first;
  63         struct tag *tl_last;
  64 };
  65 #define TAG_END  ((struct tag *) &taglist)
  66 static struct taglist taglist = { TAG_END, TAG_END };
  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 static struct tag *curtag;
  75
  76 #define TAG_INS(tp) \
  77         (tp)->next = TAG_END; \
  78         (tp)->prev = taglist.tl_last; \
  79         taglist.tl_last->next = (tp); \
  80         taglist.tl_last = (tp);
  81
  82 #define TAG_RM(tp) \
  83         (tp)->next->prev = (tp)->prev; \
  84         (tp)->prev->next = (tp)->next;
  85
  86 /*
  87  * Delete tag structures.
  88  */
  89         public void
  90 cleantags()
  91 {
  92         register struct tag *tp;
  93
  94         /*
  95          * Delete any existing tag list.
  96          * {{ Ideally, we wouldn't do this until after we know that we
  97          *    can load some other tag information. }}
  98          */
  99         while ((tp = taglist.tl_first) != TAG_END)
 100         {
 101                 TAG_RM(tp);
 102                 free(tp);
 103         }
 104         curtag = NULL;
 105         total = curseq = 0;
 106 }
 107
 108 /*
 109  * Create a new tag entry.
 110  */
 111         static struct tag *
 112 maketagent(name, file, linenum, pattern, endline)
 113         char *name;
 114         char *file;
 115         LINENUM linenum;
 116         char *pattern;
 117         int endline;
 118 {
 119         register struct tag *tp;
 120
 121         tp = (struct tag *) ecalloc(sizeof(struct tag), 1);
 122         tp->tag_file = (char *) ecalloc(strlen(file) + 1, sizeof(char));
 123         strcpy(tp->tag_file, file);
 124         tp->tag_linenum = linenum;
 125         tp->tag_endline = endline;
 126         if (pattern == NULL)
 127                 tp->tag_pattern = NULL;
 128         else
 129         {
 130                 tp->tag_pattern = (char *) ecalloc(strlen(pattern) + 1, sizeof(char));
 131                 strcpy(tp->tag_pattern, pattern);
 132         }
 133         return (tp);
 134 }
 135
 136 /*
 137  * Get tag mode.
 138  */
 139         public int
 140 gettagtype()
 141 {
 142         int f;
 143
 144         if (strcmp(tags, "GTAGS") == 0)
 145                 return T_GTAGS;
 146         if (strcmp(tags, "GRTAGS") == 0)
 147                 return T_GRTAGS;
 148         if (strcmp(tags, "GSYMS") == 0)
 149                 return T_GSYMS;
 150         if (strcmp(tags, "GPATH") == 0)
 151                 return T_GPATH;
 152         if (strcmp(tags, "-") == 0)
 153                 return T_CTAGS_X;
 154         f = open(tags, OPEN_READ);
 155         if (f >= 0)
 156         {
 157                 close(f);
 158                 return T_CTAGS;
 159         }
 160         return T_GTAGS;
 161 }
 162
 163 /*
 164  * Find tags in tag file.
 165  * Find a tag in the "tags" file.
 166  * Sets "tag_file" to the name of the file containing the tag,
 167  * and "tagpattern" to the search pattern which should be used
 168  * to find the tag.
 169  */
 170         public void
 171 findtag(tag)
 172         register char *tag;
 173 {
 174         int type = gettagtype();
 175         enum tag_result result;
 176
 177         if (type == T_CTAGS)
 178                 result = findctag(tag);
 179         else
 180                 result = findgtag(tag, type);
 181         switch (result)
 182         {
 183         case TAG_FOUND:
 184         case TAG_INTR:
 185                 break;
 186         case TAG_NOFILE:
 187                 error("No tags file", NULL_PARG);
 188                 break;
 189         case TAG_NOTAG:
 190                 error("No such tag in tags file", NULL_PARG);
 191                 break;
 192         case TAG_NOTYPE:
 193                 error("unknown tag type", NULL_PARG);
 194                 break;
 195         }
 196 }
 197
 198 /*
 199  * Search for a tag.
 200  */
 201         public POSITION
 202 tagsearch()
 203 {
 204         if (curtag == NULL)
 205                 return (NULL_POSITION);  /* No gtags loaded! */
 206         if (curtag->tag_linenum != 0)
 207                 return gtagsearch();
 208         else
 209                 return ctagsearch();
 210 }
 211
 212 /*
 213  * Go to the next tag.
 214  */
 215         public char *
 216 nexttag(n)
 217         int n;
 218 {
 219         char *tagfile = (char *) NULL;
 220
 221         while (n-- > 0)
 222                 tagfile = nextgtag();
 223         return tagfile;
 224 }
 225
 226 /*
 227  * Go to the previous tag.
 228  */
 229         public char *
 230 prevtag(n)
 231         int n;
 232 {
 233         char *tagfile = (char *) NULL;
 234
 235         while (n-- > 0)
 236                 tagfile = prevgtag();
 237         return tagfile;
 238 }
 239
 240 /*
 241  * Return the total number of tags.
 242  */
 243         public int
 244 ntags()
 245 {
 246         return total;
 247 }
 248
 249 /*
 250  * Return the sequence number of current tag.
 251  */
 252         public int
 253 curr_tag()
 254 {
 255         return curseq;
 256 }
 257
 258 /*****************************************************************************
 259  * ctags
 260  */
 261
 262 /*
 263  * Find tags in the "tags" file.
 264  * Sets curtag to the first tag entry.
 265  */
 266         static enum tag_result
 267 findctag(tag)
 268         register char *tag;
 269 {
 270         char *p;
 271         register FILE *f;
 272         register int taglen;
 273         LINENUM taglinenum;
 274         char *tagfile;
 275         char *tagpattern;
 276         int tagendline;
 277         int search_char;
 278         int err;
 279         char tline[TAGLINE_SIZE];
 280         struct tag *tp;
 281
 282         p = shell_unquote(tags);
 283         f = fopen(p, "r");
 284         free(p);
 285         if (f == NULL)
 286                 return TAG_NOFILE;
 287
 288         cleantags();
 289         total = 0;
 290         taglen = strlen(tag);
 291
 292         /*
 293          * Search the tags file for the desired tag.
 294          */
 295         while (fgets(tline, sizeof(tline), f) != NULL)
 296         {
 297                 if (tline[0] == '!')
 298                         /* Skip header of extended format. */
 299                         continue;
 300                 if (strncmp(tag, tline, taglen) != 0 || !WHITESP(tline[taglen]))
 301                         continue;
 302
 303                 /*
 304                  * Found it.
 305                  * The line contains the tag, the filename and the
 306                  * location in the file, separated by white space.
 307                  * The location is either a decimal line number,
 308                  * or a search pattern surrounded by a pair of delimiters.
 309                  * Parse the line and extract these parts.
 310                  */
 311                 tagpattern = NULL;
 312
 313                 /*
 314                  * Skip over the whitespace after the tag name.
 315                  */
 316                 p = skipsp(tline+taglen);
 317                 if (*p == '\0')
 318                         /* File name is missing! */
 319                         continue;
 320
 321                 /*
 322                  * Save the file name.
 323                  * Skip over the whitespace after the file name.
 324                  */
 325                 tagfile = p;
 326                 while (!WHITESP(*p) && *p != '\0')
 327                         p++;
 328                 *p++ = '\0';
 329                 p = skipsp(p);
 330                 if (*p == '\0')
 331                         /* Pattern is missing! */
 332                         continue;
 333
 334                 /*
 335                  * First see if it is a line number.
 336                  */
 337                 tagendline = 0;
 338                 taglinenum = getnum(&p, 0, &err);
 339                 if (err)
 340                 {
 341                         /*
 342                          * No, it must be a pattern.
 343                          * Delete the initial "^" (if present) and
 344                          * the final "$" from the pattern.
 345                          * Delete any backslash in the pattern.
 346                          */
 347                         taglinenum = 0;
 348                         search_char = *p++;
 349                         if (*p == '^')
 350                                 p++;
 351                         tagpattern = p;
 352                         while (*p != search_char && *p != '\0')
 353                         {
 354                                 if (*p == '\\')
 355                                         p++;
 356                                 p++;
 357                         }
 358                         tagendline = (p[-1] == '$');
 359                         if (tagendline)
 360                                 p--;
 361                         *p = '\0';
 362                 }
 363                 tp = maketagent(tag, tagfile, taglinenum, tagpattern, tagendline);
 364                 TAG_INS(tp);
 365                 total++;
 366         }
 367         fclose(f);
 368         if (total == 0)
 369                 return TAG_NOTAG;
 370         curtag = taglist.tl_first;
 371         curseq = 1;
 372         return TAG_FOUND;
 373 }
 374
 375 /*
 376  * Edit current tagged file.
 377  */
 378         public int
 379 edit_tagfile()
 380 {
 381         if (curtag == NULL)
 382                 return (1);
 383         return (edit(curtag->tag_file));
 384 }
 385
 386 /*
 387  * Search for a tag.
 388  * This is a stripped-down version of search().
 389  * We don't use search() for several reasons:
 390  *   -  We don't want to blow away any search string we may have saved.
 391  *   -  The various regular-expression functions (from different systems:
 392  *      regcmp vs. re_comp) behave differently in the presence of
 393  *      parentheses (which are almost always found in a tag).
 394  */
 395         static POSITION
 396 ctagsearch()
 397 {
 398         POSITION pos, linepos;
 399         LINENUM linenum;
 400         int len;
 401         char *line;
 402
 403         pos = ch_zero();
 404         linenum = find_linenum(pos);
 405
 406         for (;;)
 407         {
 408                 /*
 409                  * Get lines until we find a matching one or
 410                  * until we hit end-of-file.
 411                  */
 412                 if (ABORT_SIGS())
 413                         return (NULL_POSITION);
 414
 415                 /*
 416                  * Read the next line, and save the
 417                  * starting position of that line in linepos.
 418                  */
 419                 linepos = pos;
 420                 pos = forw_raw_line(pos, &line, (int *)NULL);
 421                 if (linenum != 0)
 422                         linenum++;
 423
 424                 if (pos == NULL_POSITION)
 425                 {
 426                         /*
 427                          * We hit EOF without a match.
 428                          */
 429                         error("Tag not found", NULL_PARG);
 430                         return (NULL_POSITION);
 431                 }
 432
 433                 /*
 434                  * If we're using line numbers, we might as well
 435                  * remember the information we have now (the position
 436                  * and line number of the current line).
 437                  */
 438                 if (linenums)
 439                         add_lnum(linenum, pos);
 440
 441                 /*
 442                  * Test the line to see if we have a match.
 443                  * Use strncmp because the pattern may be
 444                  * truncated (in the tags file) if it is too long.
 445                  * If tagendline is set, make sure we match all
 446                  * the way to end of line (no extra chars after the match).
 447                  */
 448                 len = strlen(curtag->tag_pattern);
 449                 if (strncmp(curtag->tag_pattern, line, len) == 0 &&
 450                     (!curtag->tag_endline || line[len] == '\0' || line[len] == '\r'))
 451                 {
 452                         curtag->tag_linenum = find_linenum(linepos);
 453                         break;
 454                 }
 455         }
 456
 457         return (linepos);
 458 }
 459
 460 /*******************************************************************************
 461  * gtags
 462  */
 463
 464 /*
 465  * Find tags in the GLOBAL's tag file.
 466  * The findgtag() will try and load information about the requested tag.
 467  * It does this by calling "global -x tag" and storing the parsed output
 468  * for future use by gtagsearch().
 469  * Sets curtag to the first tag entry.
 470  */
 471         static enum tag_result
 472 findgtag(tag, type)
 473         char *tag;              /* tag to load */
 474         int type;               /* tags type */
 475 {
 476         char buf[256];
 477         FILE *fp;
 478         struct tag *tp;
 479
 480         if (type != T_CTAGS_X && tag == NULL)
 481                 return TAG_NOFILE;
 482
 483         cleantags();
 484         total = 0;
 485
 486         /*
 487          * If type == T_CTAGS_X then read ctags's -x format from stdin
 488          * else execute global(1) and read from it.
 489          */
 490         if (type == T_CTAGS_X)
 491         {
 492                 fp = stdin;
 493                 /* Set tag default because we cannot read stdin again. */
 494                 tags = "tags";
 495         } else
 496         {
 497 #if !HAVE_POPEN
 498                 return TAG_NOFILE;
 499 #else
 500                 char *command;
 501                 char *flag;
 502                 char *qtag;
 503                 char *cmd = lgetenv("LESSGLOBALTAGS");
 504
 505                 if (cmd == NULL || *cmd == '\0')
 506                         return TAG_NOFILE;
 507                 /* Get suitable flag value for global(1). */
 508                 switch (type)
 509                 {
 510                 case T_GTAGS:
 511                         flag = "" ;
 512                         break;
 513                 case T_GRTAGS:
 514                         flag = "r";
 515                         break;
 516                 case T_GSYMS:
 517                         flag = "s";
 518                         break;
 519                 case T_GPATH:
 520                         flag = "P";
 521                         break;
 522                 default:
 523                         return TAG_NOTYPE;
 524                 }
 525
 526                 /* Get our data from global(1). */
 527                 qtag = shell_quote(tag);
 528                 if (qtag == NULL)
 529                         qtag = tag;
 530                 command = (char *) ecalloc(strlen(cmd) + strlen(flag) +
 531                                 strlen(qtag) + 5, sizeof(char));
 532                 sprintf(command, "%s -x%s %s", cmd, flag, qtag);
 533                 if (qtag != tag)
 534                         free(qtag);
 535                 fp = popen(command, "r");
 536                 free(command);
 537 #endif
 538         }
 539         if (fp != NULL)
 540         {
 541                 while (fgets(buf, sizeof(buf), fp))
 542                 {
 543                         char *name, *file, *line;
 544                         int len;
 545
 546                         if (sigs)
 547                         {
 548 #if HAVE_POPEN
 549                                 if (fp != stdin)
 550                                         pclose(fp);
 551 #endif
 552                                 return TAG_INTR;
 553                         }
 554                         len = strlen(buf);
 555                         if (len > 0 && buf[len-1] == '\n')
 556                                 buf[len-1] = '\0';
 557                         else
 558                         {
 559                                 int c;
 560                                 do {
 561                                         c = fgetc(fp);
 562                                 } while (c != '\n' && c != EOF);
 563                         }
 564
 565                         if (getentry(buf, &name, &file, &line))
 566                         {
 567                                 /*
 568                                  * Couldn't parse this line for some reason.
 569                                  * We'll just pretend it never happened.
 570                                  */
 571                                 break;
 572                         }
 573
 574                         /* Make new entry and add to list. */
 575                         tp = maketagent(name, file, (LINENUM) atoi(line), NULL, 0);
 576                         TAG_INS(tp);
 577                         total++;
 578                 }
 579                 if (fp != stdin)
 580                 {
 581                         if (pclose(fp))
 582                         {
 583                                 curtag = NULL;
 584                                 total = curseq = 0;
 585                                 return TAG_NOFILE;
 586                         }
 587                 }
 588         }
 589
 590         /* Check to see if we found anything. */
 591         tp = taglist.tl_first;
 592         if (tp == TAG_END)
 593                 return TAG_NOTAG;
 594         curtag = tp;
 595         curseq = 1;
 596         return TAG_FOUND;
 597 }
 598
 599 static int circular = 0;        /* 1: circular tag structure */
 600
 601 /*
 602  * Return the filename required for the next gtag in the queue that was setup
 603  * by findgtag().  The next call to gtagsearch() will try to position at the
 604  * appropriate tag.
 605  */
 606         static char *
 607 nextgtag()
 608 {
 609         struct tag *tp;
 610
 611         if (curtag == NULL)
 612                 /* No tag loaded */
 613                 return NULL;
 614
 615         tp = curtag->next;
 616         if (tp == TAG_END)
 617         {
 618                 if (!circular)
 619                         return NULL;
 620                 /* Wrapped around to the head of the queue */
 621                 curtag = taglist.tl_first;
 622                 curseq = 1;
 623         } else
 624         {
 625                 curtag = tp;
 626                 curseq++;
 627         }
 628         return (curtag->tag_file);
 629 }
 630
 631 /*
 632  * Return the filename required for the previous gtag in the queue that was
 633  * setup by findgtat().  The next call to gtagsearch() will try to position
 634  * at the appropriate tag.
 635  */
 636         static char *
 637 prevgtag()
 638 {
 639         struct tag *tp;
 640
 641         if (curtag == NULL)
 642                 /* No tag loaded */
 643                 return NULL;
 644
 645         tp = curtag->prev;
 646         if (tp == TAG_END)
 647         {
 648                 if (!circular)
 649                         return NULL;
 650                 /* Wrapped around to the tail of the queue */
 651                 curtag = taglist.tl_last;
 652                 curseq = total;
 653         } else
 654         {
 655                 curtag = tp;
 656                 curseq--;
 657         }
 658         return (curtag->tag_file);
 659 }
 660
 661 /*
 662  * Position the current file at at what is hopefully the tag that was chosen
 663  * using either findtag() or one of nextgtag() and prevgtag().  Returns -1
 664  * if it was unable to position at the tag, 0 if successful.
 665  */
 666         static POSITION
 667 gtagsearch()
 668 {
 669         if (curtag == NULL)
 670                 return (NULL_POSITION);  /* No gtags loaded! */
 671         return (find_pos(curtag->tag_linenum));
 672 }
 673
 674 /*
 675  * The getentry() parses both standard and extended ctags -x format.
 676  *
 677  * [standard format]
 678  * <tag>   <lineno>  <file>         <image>
 679  * +------------------------------------------------
 680  * |main     30      main.c         main(argc, argv)
 681  * |func     21      subr.c         func(arg)
 682  *
 683  * The following commands write this format.
 684  *      o Traditinal Ctags with -x option
 685  *      o Global with -x option
 686  *              See <http://www.gnu.org/software/global/global.html>
 687  *
 688  * [extended format]
 689  * <tag>   <type>  <lineno>   <file>        <image>
 690  * +----------------------------------------------------------
 691  * |main     function 30      main.c         main(argc, argv)
 692  * |func     function 21      subr.c         func(arg)
 693  *
 694  * The following commands write this format.
 695  *      o Exuberant Ctags with -x option
 696  *              See <http://ctags.sourceforge.net>
 697  *
 698  * Returns 0 on success, -1 on error.
 699  * The tag, file, and line will each be NUL-terminated pointers
 700  * into buf.
 701  */
 702         static int
 703 getentry(buf, tag, file, line)
 704         char *buf;      /* standard or extended ctags -x format data */
 705         char **tag;     /* name of the tag we actually found */
 706         char **file;    /* file in which to find this tag */
 707         char **line;    /* line number of file where this tag is found */
 708 {
 709         char *p = buf;
 710
 711         for (*tag = p;  *p && !IS_SPACE(*p);  p++)      /* tag name */
 712                 ;
 713         if (*p == 0)
 714                 return (-1);
 715         *p++ = 0;
 716         for ( ;  *p && IS_SPACE(*p);  p++)              /* (skip blanks) */
 717                 ;
 718         if (*p == 0)
 719                 return (-1);
 720         /*
 721          * If the second part begin with other than digit,
 722          * it is assumed tag type. Skip it.
 723          */
 724         if (!IS_DIGIT(*p))
 725         {
 726                 for ( ;  *p && !IS_SPACE(*p);  p++)     /* (skip tag type) */
 727                         ;
 728                 for (;  *p && IS_SPACE(*p);  p++)       /* (skip blanks) */
 729                         ;
 730         }
 731         if (!IS_DIGIT(*p))
 732                 return (-1);
 733         *line = p;                                      /* line number */
 734         for (*line = p;  *p && !IS_SPACE(*p);  p++)
 735                 ;
 736         if (*p == 0)
 737                 return (-1);
 738         *p++ = 0;
 739         for ( ; *p && IS_SPACE(*p);  p++)               /* (skip blanks) */
 740                 ;
 741         if (*p == 0)
 742                 return (-1);
 743         *file = p;                                      /* file name */
 744         for (*file = p;  *p && !IS_SPACE(*p);  p++)
 745                 ;
 746         if (*p == 0)
 747                 return (-1);
 748         *p = 0;
 749
 750         /* value check */
 751         if (strlen(*tag) && strlen(*line) && strlen(*file) && atoi(*line) > 0)
 752                 return (0);
 753         return (-1);
 754 }
 755
 756 #endif