contrib/less-4/tags.c

   1 /*
   2  * Copyright (C) 1984-2007  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 about less, or for information on how to
   8  * contact the author, see the README file.
   9  */
  10
  11
  12 #include "less.h"
  13
  14 #define WHITESP(c)      ((c)==' ' || (c)=='\t')
  15
  16 #if TAGS
  17
  18 public char *tags = "tags";
  19
  20 static int total;
  21 static int curseq;
  22
  23 extern int linenums;
  24 extern int sigs;
  25
  26 enum tag_result {
  27         TAG_FOUND,
  28         TAG_NOFILE,
  29         TAG_NOTAG,
  30         TAG_NOTYPE,
  31         TAG_INTR
  32 };
  33
  34 /*
  35  * Tag type
  36  */
  37 enum {
  38         T_CTAGS,        /* 'tags': standard and extended format (ctags) */
  39         T_CTAGS_X,      /* stdin: cross reference format (ctags) */
  40         T_GTAGS,        /* 'GTAGS': function defenition (global) */
  41         T_GRTAGS,       /* 'GRTAGS': function reference (global) */
  42         T_GSYMS,        /* 'GSYMS': other symbols (global) */
  43         T_GPATH         /* 'GPATH': path name (global) */
  44 };
  45
  46 static enum tag_result findctag();
  47 static enum tag_result findgtag();
  48 static char *nextgtag();
  49 static char *prevgtag();
  50 static POSITION ctagsearch();
  51 static POSITION gtagsearch();
  52 static int getentry();
  53
  54 /*
  55  * The list of tags generated by the last findgtag() call.
  56  *
  57  * Use either pattern or line number.
  58  * findgtag() always uses line number, so pattern is always NULL.
  59  * findctag() uses either pattern (in which case line number is 0),
  60  * or line number (in which case pattern is NULL).
  61  */
  62 struct taglist {
  63         struct tag *tl_first;
  64         struct tag *tl_last;
  65 };
  66 #define TAG_END  ((struct tag *) &taglist)
  67 static struct taglist taglist = { TAG_END, TAG_END };
  68 struct tag {
  69         struct tag *next, *prev; /* List links */
  70         char *tag_file;         /* Source file containing the tag */
  71         LINENUM tag_linenum;    /* Appropriate line number in source file */
  72         char *tag_pattern;      /* Pattern used to find the tag */
  73         char tag_endline;       /* True if the pattern includes '$' */
  74 };
  75 static struct tag *curtag;
  76
  77 #define TAG_INS(tp) \
  78         (tp)->next = TAG_END; \
  79         (tp)->prev = taglist.tl_last; \
  80         taglist.tl_last->next = (tp); \
  81         taglist.tl_last = (tp);
  82
  83 #define TAG_RM(tp) \
  84         (tp)->next->prev = (tp)->prev; \
  85         (tp)->prev->next = (tp)->next;
  86
  87 /*
  88  * Delete tag structures.
  89  */
  90         public void
  91 cleantags()
  92 {
  93         register 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);
 104         }
 105         curtag = NULL;
 106         total = curseq = 0;
 107 }
 108
 109 /*
 110  * Create a new tag entry.
 111  */
 112         static struct tag *
 113 maketagent(name, file, linenum, pattern, endline)
 114         char *name;
 115         char *file;
 116         LINENUM linenum;
 117         char *pattern;
 118         int endline;
 119 {
 120         register struct tag *tp;
 121
 122         tp = (struct tag *) ecalloc(sizeof(struct tag), 1);
 123         tp->tag_file = (char *) ecalloc(strlen(file) + 1, sizeof(char));
 124         strcpy(tp->tag_file, file);
 125         tp->tag_linenum = linenum;
 126         tp->tag_endline = endline;
 127         if (pattern == NULL)
 128                 tp->tag_pattern = NULL;
 129         else
 130         {
 131                 tp->tag_pattern = (char *) ecalloc(strlen(pattern) + 1, sizeof(char));
 132                 strcpy(tp->tag_pattern, pattern);
 133         }
 134         return (tp);
 135 }
 136
 137 /*
 138  * Get tag mode.
 139  */
 140         public int
 141 gettagtype()
 142 {
 143         int f;
 144
 145         if (strcmp(tags, "GTAGS") == 0)
 146                 return T_GTAGS;
 147         if (strcmp(tags, "GRTAGS") == 0)
 148                 return T_GRTAGS;
 149         if (strcmp(tags, "GSYMS") == 0)
 150                 return T_GSYMS;
 151         if (strcmp(tags, "GPATH") == 0)
 152                 return T_GPATH;
 153         if (strcmp(tags, "-") == 0)
 154                 return T_CTAGS_X;
 155         f = open(tags, OPEN_READ);
 156         if (f >= 0)
 157         {
 158                 close(f);
 159                 return T_CTAGS;
 160         }
 161         return T_GTAGS;
 162 }
 163
 164 /*
 165  * Find tags in tag file.
 166  * Find a tag in the "tags" file.
 167  * Sets "tag_file" to the name of the file containing the tag,
 168  * and "tagpattern" to the search pattern which should be used
 169  * to find the tag.
 170  */
 171         public void
 172 findtag(tag)
 173         register char *tag;
 174 {
 175         int type = gettagtype();
 176         enum tag_result result;
 177
 178         if (type == T_CTAGS)
 179                 result = findctag(tag);
 180         else
 181                 result = findgtag(tag, type);
 182         switch (result)
 183         {
 184         case TAG_FOUND:
 185         case TAG_INTR:
 186                 break;
 187         case TAG_NOFILE:
 188                 error("No tags file", NULL_PARG);
 189                 break;
 190         case TAG_NOTAG:
 191                 error("No such tag in tags file", NULL_PARG);
 192                 break;
 193         case TAG_NOTYPE:
 194                 error("unknown tag type", NULL_PARG);
 195                 break;
 196         }
 197 }
 198
 199 /*
 200  * Search for a tag.
 201  */
 202         public POSITION
 203 tagsearch()
 204 {
 205         if (curtag == NULL)
 206                 return (NULL_POSITION);  /* No gtags loaded! */
 207         if (curtag->tag_linenum != 0)
 208                 return gtagsearch();
 209         else
 210                 return ctagsearch();
 211 }
 212
 213 /*
 214  * Go to the next tag.
 215  */
 216         public char *
 217 nexttag(n)
 218         int n;
 219 {
 220         char *tagfile = (char *) NULL;
 221
 222         while (n-- > 0)
 223                 tagfile = nextgtag();
 224         return tagfile;
 225 }
 226
 227 /*
 228  * Go to the previous tag.
 229  */
 230         public char *
 231 prevtag(n)
 232         int n;
 233 {
 234         char *tagfile = (char *) NULL;
 235
 236         while (n-- > 0)
 237                 tagfile = prevgtag();
 238         return tagfile;
 239 }
 240
 241 /*
 242  * Return the total number of tags.
 243  */
 244         public int
 245 ntags()
 246 {
 247         return total;
 248 }
 249
 250 /*
 251  * Return the sequence number of current tag.
 252  */
 253         public int
 254 curr_tag()
 255 {
 256         return curseq;
 257 }
 258
 259 /*****************************************************************************
 260  * ctags
 261  */
 262
 263 /*
 264  * Find tags in the "tags" file.
 265  * Sets curtag to the first tag entry.
 266  */
 267         static enum tag_result
 268 findctag(tag)
 269         register char *tag;
 270 {
 271         char *p;
 272         register FILE *f;
 273         register int taglen;
 274         LINENUM taglinenum;
 275         char *tagfile;
 276         char *tagpattern;
 277         int tagendline;
 278         int search_char;
 279         int err;
 280         char tline[TAGLINE_SIZE];
 281         struct tag *tp;
 282
 283         p = shell_unquote(tags);
 284         f = fopen(p, "r");
 285         free(p);
 286         if (f == NULL)
 287                 return TAG_NOFILE;
 288
 289         cleantags();
 290         total = 0;
 291         taglen = strlen(tag);
 292
 293         /*
 294          * Search the tags file for the desired tag.
 295          */
 296         while (fgets(tline, sizeof(tline), f) != NULL)
 297         {
 298                 if (tline[0] == '!')
 299                         /* Skip header of extended format. */
 300                         continue;
 301                 if (strncmp(tag, tline, taglen) != 0 || !WHITESP(tline[taglen]))
 302                         continue;
 303
 304                 /*
 305                  * Found it.
 306                  * The line contains the tag, the filename and the
 307                  * location in the file, separated by white space.
 308                  * The location is either a decimal line number,
 309                  * or a search pattern surrounded by a pair of delimiters.
 310                  * Parse the line and extract these parts.
 311                  */
 312                 tagpattern = NULL;
 313
 314                 /*
 315                  * Skip over the whitespace after the tag name.
 316                  */
 317                 p = skipsp(tline+taglen);
 318                 if (*p == '\0')
 319                         /* File name is missing! */
 320                         continue;
 321
 322                 /*
 323                  * Save the file name.
 324                  * Skip over the whitespace after the file name.
 325                  */
 326                 tagfile = p;
 327                 while (!WHITESP(*p) && *p != '\0')
 328                         p++;
 329                 *p++ = '\0';
 330                 p = skipsp(p);
 331                 if (*p == '\0')
 332                         /* Pattern is missing! */
 333                         continue;
 334
 335                 /*
 336                  * First see if it is a line number.
 337                  */
 338                 tagendline = 0;
 339                 taglinenum = getnum(&p, 0, &err);
 340                 if (err)
 341                 {
 342                         /*
 343                          * No, it must be a pattern.
 344                          * Delete the initial "^" (if present) and
 345                          * the final "$" from the pattern.
 346                          * Delete any backslash in the pattern.
 347                          */
 348                         taglinenum = 0;
 349                         search_char = *p++;
 350                         if (*p == '^')
 351                                 p++;
 352                         tagpattern = p;
 353                         while (*p != search_char && *p != '\0')
 354                         {
 355                                 if (*p == '\\')
 356                                         p++;
 357                                 p++;
 358                         }
 359                         tagendline = (p[-1] == '$');
 360                         if (tagendline)
 361                                 p--;
 362                         *p = '\0';
 363                 }
 364                 tp = maketagent(tag, tagfile, taglinenum, tagpattern, tagendline);
 365                 TAG_INS(tp);
 366                 total++;
 367         }
 368         fclose(f);
 369         if (total == 0)
 370                 return TAG_NOTAG;
 371         curtag = taglist.tl_first;
 372         curseq = 1;
 373         return TAG_FOUND;
 374 }
 375
 376 /*
 377  * Edit current tagged file.
 378  */
 379         public int
 380 edit_tagfile()
 381 {
 382         if (curtag == NULL)
 383                 return (1);
 384         return (edit(curtag->tag_file));
 385 }
 386
 387 /*
 388  * Search for a tag.
 389  * This is a stripped-down version of search().
 390  * We don't use search() for several reasons:
 391  *   -  We don't want to blow away any search string we may have saved.
 392  *   -  The various regular-expression functions (from different systems:
 393  *      regcmp vs. re_comp) behave differently in the presence of
 394  *      parentheses (which are almost always found in a tag).
 395  */
 396         static POSITION
 397 ctagsearch()
 398 {
 399         POSITION pos, linepos;
 400         LINENUM linenum;
 401         int len;
 402         char *line;
 403
 404         pos = ch_zero();
 405         linenum = find_linenum(pos);
 406
 407         for (;;)
 408         {
 409                 /*
 410                  * Get lines until we find a matching one or
 411                  * until we hit end-of-file.
 412                  */
 413                 if (ABORT_SIGS())
 414                         return (NULL_POSITION);
 415
 416                 /*
 417                  * Read the next line, and save the
 418                  * starting position of that line in linepos.
 419                  */
 420                 linepos = pos;
 421                 pos = forw_raw_line(pos, &line, (int *)NULL);
 422                 if (linenum != 0)
 423                         linenum++;
 424
 425                 if (pos == NULL_POSITION)
 426                 {
 427                         /*
 428                          * We hit EOF without a match.
 429                          */
 430                         error("Tag not found", NULL_PARG);
 431                         return (NULL_POSITION);
 432                 }
 433
 434                 /*
 435                  * If we're using line numbers, we might as well
 436                  * remember the information we have now (the position
 437                  * and line number of the current line).
 438                  */
 439                 if (linenums)
 440                         add_lnum(linenum, pos);
 441
 442                 /*
 443                  * Test the line to see if we have a match.
 444                  * Use strncmp because the pattern may be
 445                  * truncated (in the tags file) if it is too long.
 446                  * If tagendline is set, make sure we match all
 447                  * the way to end of line (no extra chars after the match).
 448                  */
 449                 len = strlen(curtag->tag_pattern);
 450                 if (strncmp(curtag->tag_pattern, line, len) == 0 &&
 451                     (!curtag->tag_endline || line[len] == '\0' || line[len] == '\r'))
 452                 {
 453                         curtag->tag_linenum = find_linenum(linepos);
 454                         break;
 455                 }
 456         }
 457
 458         return (linepos);
 459 }
 460
 461 /*******************************************************************************
 462  * gtags
 463  */
 464
 465 /*
 466  * Find tags in the GLOBAL's tag file.
 467  * The findgtag() will try and load information about the requested tag.
 468  * It does this by calling "global -x tag" and storing the parsed output
 469  * for future use by gtagsearch().
 470  * Sets curtag to the first tag entry.
 471  */
 472         static enum tag_result
 473 findgtag(tag, type)
 474         char *tag;              /* tag to load */
 475         int type;               /* tags type */
 476 {
 477         char buf[256];
 478         FILE *fp;
 479         struct tag *tp;
 480
 481         if (type != T_CTAGS_X && tag == NULL)
 482                 return TAG_NOFILE;
 483
 484         cleantags();
 485         total = 0;
 486
 487         /*
 488          * If type == T_CTAGS_X then read ctags's -x format from stdin
 489          * else execute global(1) and read from it.
 490          */
 491         if (type == T_CTAGS_X)
 492         {
 493                 fp = stdin;
 494                 /* Set tag default because we cannot read stdin again. */
 495                 tags = "tags";
 496         } else
 497         {
 498 #if !HAVE_POPEN
 499                 return TAG_NOFILE;
 500 #else
 501                 char *command;
 502                 char *flag;
 503                 char *qtag;
 504                 char *cmd = lgetenv("LESSGLOBALTAGS");
 505
 506                 if (cmd == NULL || *cmd == '\0')
 507                         return TAG_NOFILE;
 508                 /* Get suitable flag value for global(1). */
 509                 switch (type)
 510                 {
 511                 case T_GTAGS:
 512                         flag = "" ;
 513                         break;
 514                 case T_GRTAGS:
 515                         flag = "r";
 516                         break;
 517                 case T_GSYMS:
 518                         flag = "s";
 519                         break;
 520                 case T_GPATH:
 521                         flag = "P";
 522                         break;
 523                 default:
 524                         return TAG_NOTYPE;
 525                 }
 526
 527                 /* Get our data from global(1). */
 528                 qtag = shell_quote(tag);
 529                 if (qtag == NULL)
 530                         qtag = tag;
 531                 command = (char *) ecalloc(strlen(cmd) + strlen(flag) +
 532                                 strlen(qtag) + 5, sizeof(char));
 533                 sprintf(command, "%s -x%s %s", cmd, flag, qtag);
 534                 if (qtag != tag)
 535                         free(qtag);
 536                 fp = popen(command, "r");
 537                 free(command);
 538 #endif
 539         }
 540         if (fp != NULL)
 541         {
 542                 while (fgets(buf, sizeof(buf), fp))
 543                 {
 544                         char *name, *file, *line;
 545                         int len;
 546
 547                         if (sigs)
 548                         {
 549 #if HAVE_POPEN
 550                                 if (fp != stdin)
 551                                         pclose(fp);
 552 #endif
 553                                 return TAG_INTR;
 554                         }
 555                         len = strlen(buf);
 556                         if (len > 0 && buf[len-1] == '\n')
 557                                 buf[len-1] = '\0';
 558                         else
 559                         {
 560                                 int c;
 561                                 do {
 562                                         c = fgetc(fp);
 563                                 } while (c != '\n' && c != EOF);
 564                         }
 565
 566                         if (getentry(buf, &name, &file, &line))
 567                         {
 568                                 /*
 569                                  * Couldn't parse this line for some reason.
 570                                  * We'll just pretend it never happened.
 571                                  */
 572                                 break;
 573                         }
 574
 575                         /* Make new entry and add to list. */
 576                         tp = maketagent(name, file, (LINENUM) atoi(line), NULL, 0);
 577                         TAG_INS(tp);
 578                         total++;
 579                 }
 580                 if (fp != stdin)
 581                 {
 582                         if (pclose(fp))
 583                         {
 584                                 curtag = NULL;
 585                                 total = curseq = 0;
 586                                 return TAG_NOFILE;
 587                         }
 588                 }
 589         }
 590
 591         /* Check to see if we found anything. */
 592         tp = taglist.tl_first;
 593         if (tp == TAG_END)
 594                 return TAG_NOTAG;
 595         curtag = tp;
 596         curseq = 1;
 597         return TAG_FOUND;
 598 }
 599
 600 static int circular = 0;        /* 1: circular tag structure */
 601
 602 /*
 603  * Return the filename required for the next gtag in the queue that was setup
 604  * by findgtag().  The next call to gtagsearch() will try to position at the
 605  * appropriate tag.
 606  */
 607         static char *
 608 nextgtag()
 609 {
 610         struct tag *tp;
 611
 612         if (curtag == NULL)
 613                 /* No tag loaded */
 614                 return NULL;
 615
 616         tp = curtag->next;
 617         if (tp == TAG_END)
 618         {
 619                 if (!circular)
 620                         return NULL;
 621                 /* Wrapped around to the head of the queue */
 622                 curtag = taglist.tl_first;
 623                 curseq = 1;
 624         } else
 625         {
 626                 curtag = tp;
 627                 curseq++;
 628         }
 629         return (curtag->tag_file);
 630 }
 631
 632 /*
 633  * Return the filename required for the previous gtag in the queue that was
 634  * setup by findgtat().  The next call to gtagsearch() will try to position
 635  * at the appropriate tag.
 636  */
 637         static char *
 638 prevgtag()
 639 {
 640         struct tag *tp;
 641
 642         if (curtag == NULL)
 643                 /* No tag loaded */
 644                 return NULL;
 645
 646         tp = curtag->prev;
 647         if (tp == TAG_END)
 648         {
 649                 if (!circular)
 650                         return NULL;
 651                 /* Wrapped around to the tail of the queue */
 652                 curtag = taglist.tl_last;
 653                 curseq = total;
 654         } else
 655         {
 656                 curtag = tp;
 657                 curseq--;
 658         }
 659         return (curtag->tag_file);
 660 }
 661
 662 /*
 663  * Position the current file at at what is hopefully the tag that was chosen
 664  * using either findtag() or one of nextgtag() and prevgtag().  Returns -1
 665  * if it was unable to position at the tag, 0 if succesful.
 666  */
 667         static POSITION
 668 gtagsearch()
 669 {
 670         if (curtag == NULL)
 671                 return (NULL_POSITION);  /* No gtags loaded! */
 672         return (find_pos(curtag->tag_linenum));
 673 }
 674
 675 /*
 676  * The getentry() parses both standard and extended ctags -x format.
 677  *
 678  * [standard format]
 679  * <tag>   <lineno>  <file>         <image>
 680  * +------------------------------------------------
 681  * |main     30      main.c         main(argc, argv)
 682  * |func     21      subr.c         func(arg)
 683  *
 684  * The following commands write this format.
 685  *      o Traditinal Ctags with -x option
 686  *      o Global with -x option
 687  *              See <http://www.gnu.org/software/global/global.html>
 688  *
 689  * [extended format]
 690  * <tag>   <type>  <lineno>   <file>        <image>
 691  * +----------------------------------------------------------
 692  * |main     function 30      main.c         main(argc, argv)
 693  * |func     function 21      subr.c         func(arg)
 694  *
 695  * The following commands write this format.
 696  *      o Exuberant Ctags with -x option
 697  *              See <http://ctags.sourceforge.net>
 698  *
 699  * Returns 0 on success, -1 on error.
 700  * The tag, file, and line will each be NUL-terminated pointers
 701  * into buf.
 702  */
 703         static int
 704 getentry(buf, tag, file, line)
 705         char *buf;      /* standard or extended ctags -x format data */
 706         char **tag;     /* name of the tag we actually found */
 707         char **file;    /* file in which to find this tag */
 708         char **line;    /* line number of file where this tag is found */
 709 {
 710         char *p = buf;
 711
 712         for (*tag = p;  *p && !IS_SPACE(*p);  p++)      /* tag name */
 713                 ;
 714         if (*p == 0)
 715                 return (-1);
 716         *p++ = 0;
 717         for ( ;  *p && IS_SPACE(*p);  p++)              /* (skip blanks) */
 718                 ;
 719         if (*p == 0)
 720                 return (-1);
 721         /*
 722          * If the second part begin with other than digit,
 723          * it is assumed tag type. Skip it.
 724          */
 725         if (!IS_DIGIT(*p))
 726         {
 727                 for ( ;  *p && !IS_SPACE(*p);  p++)     /* (skip tag type) */
 728                         ;
 729                 for (;  *p && IS_SPACE(*p);  p++)       /* (skip blanks) */
 730                         ;
 731         }
 732         if (!IS_DIGIT(*p))
 733                 return (-1);
 734         *line = p;                                      /* line number */
 735         for (*line = p;  *p && !IS_SPACE(*p);  p++)
 736                 ;
 737         if (*p == 0)
 738                 return (-1);
 739         *p++ = 0;
 740         for ( ; *p && IS_SPACE(*p);  p++)               /* (skip blanks) */
 741                 ;
 742         if (*p == 0)
 743                 return (-1);
 744         *file = p;                                      /* file name */
 745         for (*file = p;  *p && !IS_SPACE(*p);  p++)
 746                 ;
 747         if (*p == 0)
 748                 return (-1);
 749         *p = 0;
 750
 751         /* value check */
 752         if (strlen(*tag) && strlen(*line) && strlen(*file) && atoi(*line) > 0)
 753                 return (0);
 754         return (-1);
 755 }
 756
 757 #endif