contrib/less/prompt.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 /*
  12  * Prompting and other messages.
  13  * There are three flavors of prompts, SHORT, MEDIUM and LONG,
  14  * selected by the -m/-M options.
  15  * There is also the "equals message", printed by the = command.
  16  * A prompt is a message composed of various pieces, such as the
  17  * name of the file being viewed, the percentage into the file, etc.
  18  */
  19
  20 #include "less.h"
  21 #include "position.h"
  22
  23 extern int pr_type;
  24 extern int new_file;
  25 extern int sc_width;
  26 extern int so_s_width, so_e_width;
  27 extern int linenums;
  28 extern int hshift;
  29 extern int sc_height;
  30 extern int jump_sline;
  31 extern int less_is_more;
  32 extern int header_lines;
  33 extern IFILE curr_ifile;
  34 #if EDITOR
  35 extern char *editor;
  36 extern char *editproto;
  37 #endif
  38
  39 /*
  40  * Prototypes for the three flavors of prompts.
  41  * These strings are expanded by pr_expand().
  42  */
  43 static constant char s_proto[] =
  44   "?n?f%f .?m(%T %i of %m) ..?e(END) ?x- Next\\: %x..%t";
  45 static constant char m_proto[] =
  46   "?n?f%f .?m(%T %i of %m) ..?e(END) ?x- Next\\: %x.:?pB%pB\\%:byte %bB?s/%s...%t";
  47 static constant char M_proto[] =
  48   "?f%f .?n?m(%T %i of %m) ..?ltlines %lt-%lb?L/%L. :byte %bB?s/%s. .?e(END) ?x- Next\\: %x.:?pB%pB\\%..%t";
  49 static constant char e_proto[] =
  50   "?f%f .?m(%T %i of %m) .?ltlines %lt-%lb?L/%L. .byte %bB?s/%s. ?e(END) :?pB%pB\\%..%t";
  51 static constant char h_proto[] =
  52   "HELP -- ?eEND -- Press g to see it again:Press RETURN for more., or q when done";
  53 static constant char w_proto[] =
  54   "Waiting for data";
  55 static constant char more_proto[] =
  56   "--More--(?eEND ?x- Next\\: %x.:?pB%pB\\%:byte %bB?s/%s...%t)";
  57
  58 public char *prproto[3];
  59 public char constant *eqproto = e_proto;
  60 public char constant *hproto = h_proto;
  61 public char constant *wproto = w_proto;
  62
  63 static char message[PROMPT_SIZE];
  64 static char *mp;
  65
  66 /*
  67  * Initialize the prompt prototype strings.
  68  */
  69         public void
  70 init_prompt(VOID_PARAM)
  71 {
  72         prproto[0] = save(s_proto);
  73         prproto[1] = save(less_is_more ? more_proto : m_proto);
  74         prproto[2] = save(M_proto);
  75         eqproto = save(e_proto);
  76         hproto = save(h_proto);
  77         wproto = save(w_proto);
  78 }
  79
  80 /*
  81  * Append a string to the end of the message.
  82  */
  83         static void
  84 ap_str(s)
  85         char *s;
  86 {
  87         int len;
  88
  89         len = (int) strlen(s);
  90         if (mp + len >= message + PROMPT_SIZE)
  91                 len = (int) (message + PROMPT_SIZE - mp - 1);
  92         strncpy(mp, s, len);
  93         mp += len;
  94         *mp = '\0';
  95 }
  96
  97 /*
  98  * Append a character to the end of the message.
  99  */
 100         static void
 101 ap_char(c)
 102         char c;
 103 {
 104         char buf[2];
 105
 106         buf[0] = c;
 107         buf[1] = '\0';
 108         ap_str(buf);
 109 }
 110
 111 /*
 112  * Append a POSITION (as a decimal integer) to the end of the message.
 113  */
 114         static void
 115 ap_pos(pos)
 116         POSITION pos;
 117 {
 118         char buf[INT_STRLEN_BOUND(pos) + 2];
 119
 120         postoa(pos, buf);
 121         ap_str(buf);
 122 }
 123
 124 /*
 125  * Append a line number to the end of the message.
 126  */
 127         static void
 128 ap_linenum(linenum)
 129         LINENUM linenum;
 130 {
 131         char buf[INT_STRLEN_BOUND(linenum) + 2];
 132
 133         linenumtoa(linenum, buf);
 134         ap_str(buf);
 135 }
 136
 137 /*
 138  * Append an integer to the end of the message.
 139  */
 140         static void
 141 ap_int(num)
 142         int num;
 143 {
 144         char buf[INT_STRLEN_BOUND(num) + 2];
 145
 146         inttoa(num, buf);
 147         ap_str(buf);
 148 }
 149
 150 /*
 151  * Append a question mark to the end of the message.
 152  */
 153         static void
 154 ap_quest(VOID_PARAM)
 155 {
 156         ap_str("?");
 157 }
 158
 159 /*
 160  * Return the "current" byte offset in the file.
 161  */
 162         static POSITION
 163 curr_byte(where)
 164         int where;
 165 {
 166         POSITION pos;
 167
 168         pos = position(where);
 169         while (pos == NULL_POSITION && where >= 0 && where < sc_height-1)
 170                 pos = position(++where);
 171         if (pos == NULL_POSITION)
 172                 pos = ch_length();
 173         return (pos);
 174 }
 175
 176 /*
 177  * Return the value of a prototype conditional.
 178  * A prototype string may include conditionals which consist of a
 179  * question mark followed by a single letter.
 180  * Here we decode that letter and return the appropriate boolean value.
 181  */
 182         static int
 183 cond(c, where)
 184         char c;
 185         int where;
 186 {
 187         POSITION len;
 188
 189         switch (c)
 190         {
 191         case 'a': /* Anything in the message yet? */
 192                 return (mp > message);
 193         case 'b': /* Current byte offset known? */
 194                 return (curr_byte(where) != NULL_POSITION);
 195         case 'c':
 196                 return (hshift != 0);
 197         case 'e': /* At end of file? */
 198                 return (eof_displayed());
 199         case 'f': /* Filename known? */
 200         case 'g':
 201                 return (strcmp(get_filename(curr_ifile), "-") != 0);
 202         case 'l': /* Line number known? */
 203         case 'd': /* Same as l */
 204                 if (!linenums)
 205                         return 0;
 206                 return (currline(where) != 0);
 207         case 'L': /* Final line number known? */
 208         case 'D': /* Final page number known? */
 209                 return (linenums && ch_length() != NULL_POSITION);
 210         case 'm': /* More than one file? */
 211 #if TAGS
 212                 return (ntags() ? (ntags() > 1) : (nifile() > 1));
 213 #else
 214                 return (nifile() > 1);
 215 #endif
 216         case 'n': /* First prompt in a new file? */
 217 #if TAGS
 218                 return (ntags() ? 1 : new_file);
 219 #else
 220                 return (new_file);
 221 #endif
 222         case 'p': /* Percent into file (bytes) known? */
 223                 return (curr_byte(where) != NULL_POSITION &&
 224                                 ch_length() > 0);
 225         case 'P': /* Percent into file (lines) known? */
 226                 return (currline(where) != 0 &&
 227                                 (len = ch_length()) > 0 &&
 228                                 find_linenum(len) != 0);
 229         case 's': /* Size of file known? */
 230         case 'B':
 231                 return (ch_length() != NULL_POSITION);
 232         case 'x': /* Is there a "next" file? */
 233 #if TAGS
 234                 if (ntags())
 235                         return (0);
 236 #endif
 237                 return (next_ifile(curr_ifile) != NULL_IFILE);
 238         }
 239         return (0);
 240 }
 241
 242 /*
 243  * Decode a "percent" prototype character.
 244  * A prototype string may include various "percent" escapes;
 245  * that is, a percent sign followed by a single letter.
 246  * Here we decode that letter and take the appropriate action,
 247  * usually by appending something to the message being built.
 248  */
 249         static void
 250 protochar(c, where, iseditproto)
 251         int c;
 252         int where;
 253         int iseditproto;
 254 {
 255         POSITION pos;
 256         POSITION len;
 257         int n;
 258         LINENUM linenum;
 259         LINENUM last_linenum;
 260         IFILE h;
 261         char *s;
 262
 263 #undef  PAGE_NUM
 264 #define PAGE_NUM(linenum)  ((((linenum) - 1) / (sc_height - header_lines - 1)) + 1)
 265
 266         switch (c)
 267         {
 268         case 'b': /* Current byte offset */
 269                 pos = curr_byte(where);
 270                 if (pos != NULL_POSITION)
 271                         ap_pos(pos);
 272                 else
 273                         ap_quest();
 274                 break;
 275         case 'c':
 276                 ap_int(hshift);
 277                 break;
 278         case 'd': /* Current page number */
 279                 linenum = currline(where);
 280                 if (linenum > 0 && sc_height > header_lines + 1)
 281                         ap_linenum(PAGE_NUM(linenum));
 282                 else
 283                         ap_quest();
 284                 break;
 285         case 'D': /* Final page number */
 286                 /* Find the page number of the last byte in the file (len-1). */
 287                 len = ch_length();
 288                 if (len == NULL_POSITION)
 289                         ap_quest();
 290                 else if (len == 0)
 291                         /* An empty file has no pages. */
 292                         ap_linenum(0);
 293                 else
 294                 {
 295                         linenum = find_linenum(len - 1);
 296                         if (linenum <= 0)
 297                                 ap_quest();
 298                         else
 299                                 ap_linenum(PAGE_NUM(linenum));
 300                 }
 301                 break;
 302 #if EDITOR
 303         case 'E': /* Editor name */
 304                 ap_str(editor);
 305                 break;
 306 #endif
 307         case 'f': /* File name */
 308                 ap_str(get_filename(curr_ifile));
 309                 break;
 310         case 'F': /* Last component of file name */
 311                 ap_str(last_component(get_filename(curr_ifile)));
 312                 break;
 313         case 'g': /* Shell-escaped file name */
 314                 s = shell_quote(get_filename(curr_ifile));
 315                 ap_str(s);
 316                 free(s);
 317                 break;
 318         case 'i': /* Index into list of files */
 319 #if TAGS
 320                 if (ntags())
 321                         ap_int(curr_tag());
 322                 else
 323 #endif
 324                         ap_int(get_index(curr_ifile));
 325                 break;
 326         case 'l': /* Current line number */
 327                 linenum = currline(where);
 328                 if (linenum != 0)
 329                         ap_linenum(vlinenum(linenum));
 330                 else
 331                         ap_quest();
 332                 break;
 333         case 'L': /* Final line number */
 334                 len = ch_length();
 335                 if (len == NULL_POSITION || len == ch_zero() ||
 336                     (linenum = find_linenum(len)) <= 0)
 337                         ap_quest();
 338                 else
 339                         ap_linenum(vlinenum(linenum-1));
 340                 break;
 341         case 'm': /* Number of files */
 342 #if TAGS
 343                 n = ntags();
 344                 if (n)
 345                         ap_int(n);
 346                 else
 347 #endif
 348                         ap_int(nifile());
 349                 break;
 350         case 'p': /* Percent into file (bytes) */
 351                 pos = curr_byte(where);
 352                 len = ch_length();
 353                 if (pos != NULL_POSITION && len > 0)
 354                         ap_int(percentage(pos,len));
 355                 else
 356                         ap_quest();
 357                 break;
 358         case 'P': /* Percent into file (lines) */
 359                 linenum = currline(where);
 360                 if (linenum == 0 ||
 361                     (len = ch_length()) == NULL_POSITION || len == ch_zero() ||
 362                     (last_linenum = find_linenum(len)) <= 0)
 363                         ap_quest();
 364                 else
 365                         ap_int(percentage(linenum, last_linenum));
 366                 break;
 367         case 's': /* Size of file */
 368         case 'B':
 369                 len = ch_length();
 370                 if (len != NULL_POSITION)
 371                         ap_pos(len);
 372                 else
 373                         ap_quest();
 374                 break;
 375         case 't': /* Truncate trailing spaces in the message */
 376                 while (mp > message && mp[-1] == ' ')
 377                         mp--;
 378                 *mp = '\0';
 379                 break;
 380         case 'T': /* Type of list */
 381 #if TAGS
 382                 if (ntags())
 383                         ap_str("tag");
 384                 else
 385 #endif
 386                         ap_str("file");
 387                 break;
 388         case 'x': /* Name of next file */
 389                 h = next_ifile(curr_ifile);
 390                 if (h != NULL_IFILE)
 391                         ap_str(get_filename(h));
 392                 else
 393                         ap_quest();
 394                 break;
 395         }
 396 }
 397
 398 /*
 399  * Skip a false conditional.
 400  * When a false condition is found (either a false IF or the ELSE part
 401  * of a true IF), this routine scans the prototype string to decide
 402  * where to resume parsing the string.
 403  * We must keep track of nested IFs and skip them properly.
 404  */
 405         static constant char *
 406 skipcond(p)
 407         constant char *p;
 408 {
 409         int iflevel;
 410
 411         /*
 412          * We came in here after processing a ? or :,
 413          * so we start nested one level deep.
 414          */
 415         iflevel = 1;
 416
 417         for (;;) switch (*++p)
 418         {
 419         case '?':
 420                 /*
 421                  * Start of a nested IF.
 422                  */
 423                 iflevel++;
 424                 break;
 425         case ':':
 426                 /*
 427                  * Else.
 428                  * If this matches the IF we came in here with,
 429                  * then we're done.
 430                  */
 431                 if (iflevel == 1)
 432                         return (p);
 433                 break;
 434         case '.':
 435                 /*
 436                  * Endif.
 437                  * If this matches the IF we came in here with,
 438                  * then we're done.
 439                  */
 440                 if (--iflevel == 0)
 441                         return (p);
 442                 break;
 443         case '\\':
 444                 /*
 445                  * Backslash escapes the next character.
 446                  */
 447                 ++p;
 448                 break;
 449         case '\0':
 450                 /*
 451                  * Whoops.  Hit end of string.
 452                  * This is a malformed conditional, but just treat it
 453                  * as if all active conditionals ends here.
 454                  */
 455                 return (p-1);
 456         }
 457         /*NOTREACHED*/
 458 }
 459
 460 /*
 461  * Decode a char that represents a position on the screen.
 462  */
 463         static constant char *
 464 wherechar(p, wp)
 465         char constant *p;
 466         int *wp;
 467 {
 468         switch (*p)
 469         {
 470         case 'b': case 'd': case 'l': case 'p': case 'P':
 471                 switch (*++p)
 472                 {
 473                 case 't':   *wp = TOP;                  break;
 474                 case 'm':   *wp = MIDDLE;               break;
 475                 case 'b':   *wp = BOTTOM;               break;
 476                 case 'B':   *wp = BOTTOM_PLUS_ONE;      break;
 477                 case 'j':   *wp = sindex_from_sline(jump_sline); break;
 478                 default:    *wp = TOP;  p--;            break;
 479                 }
 480         }
 481         return (p);
 482 }
 483
 484 /*
 485  * Construct a message based on a prototype string.
 486  */
 487         public char *
 488 pr_expand(proto)
 489         constant char *proto;
 490 {
 491         constant char *p;
 492         int c;
 493         int where;
 494
 495         mp = message;
 496
 497         if (*proto == '\0')
 498                 return ("");
 499
 500         for (p = proto;  *p != '\0';  p++)
 501         {
 502                 switch (*p)
 503                 {
 504                 default: /* Just put the character in the message */
 505                         ap_char(*p);
 506                         break;
 507                 case '\\': /* Backslash escapes the next character */
 508                         p++;
 509                         ap_char(*p);
 510                         break;
 511                 case '?': /* Conditional (IF) */
 512                         if ((c = *++p) == '\0')
 513                                 --p;
 514                         else
 515                         {
 516                                 where = 0;
 517                                 p = wherechar(p, &where);
 518                                 if (!cond(c, where))
 519                                         p = skipcond(p);
 520                         }
 521                         break;
 522                 case ':': /* ELSE */
 523                         p = skipcond(p);
 524                         break;
 525                 case '.': /* ENDIF */
 526                         break;
 527                 case '%': /* Percent escape */
 528                         if ((c = *++p) == '\0')
 529                                 --p;
 530                         else
 531                         {
 532                                 where = 0;
 533                                 p = wherechar(p, &where);
 534                                 protochar(c, where,
 535 #if EDITOR
 536                                         (proto == editproto));
 537 #else
 538                                         0);
 539 #endif
 540
 541                         }
 542                         break;
 543                 }
 544         }
 545
 546         if (mp == message)
 547                 return ("");
 548         return (message);
 549 }
 550
 551 /*
 552  * Return a message suitable for printing by the "=" command.
 553  */
 554         public char *
 555 eq_message(VOID_PARAM)
 556 {
 557         return (pr_expand(eqproto));
 558 }
 559
 560 /*
 561  * Return a prompt.
 562  * This depends on the prompt type (SHORT, MEDIUM, LONG), etc.
 563  * If we can't come up with an appropriate prompt, return NULL
 564  * and the caller will prompt with a colon.
 565  */
 566         public char *
 567 pr_string(VOID_PARAM)
 568 {
 569         char *prompt;
 570         int type;
 571
 572         type = (!less_is_more) ? pr_type : pr_type ? 0 : 1;
 573         prompt = pr_expand((ch_getflags() & CH_HELPFILE) ?
 574                                 hproto : prproto[type]);
 575         new_file = 0;
 576         return (prompt);
 577 }
 578
 579 /*
 580  * Return a message suitable for printing while waiting in the F command.
 581  */
 582         public char *
 583 wait_message(VOID_PARAM)
 584 {
 585         return (pr_expand(wproto));
 586 }