contrib/less-4/cmdbuf.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 /*
  13  * Functions which manipulate the command buffer.
  14  * Used only by command() and related functions.
  15  */
  16
  17 #include "less.h"
  18 #include "cmd.h"
  19 #include "charset.h"
  20 #if HAVE_STAT
  21 #include <sys/stat.h>
  22 #endif
  23
  24 extern int sc_width;
  25 extern int utf_mode;
  26
  27 static char cmdbuf[CMDBUF_SIZE]; /* Buffer for holding a multi-char command */
  28 static int cmd_col;             /* Current column of the cursor */
  29 static int prompt_col;          /* Column of cursor just after prompt */
  30 static char *cp;                /* Pointer into cmdbuf */
  31 static int cmd_offset;          /* Index into cmdbuf of first displayed char */
  32 static int literal;             /* Next input char should not be interpreted */
  33
  34 #if TAB_COMPLETE_FILENAME
  35 static int cmd_complete();
  36 /*
  37  * These variables are statics used by cmd_complete.
  38  */
  39 static int in_completion = 0;
  40 static char *tk_text;
  41 static char *tk_original;
  42 static char *tk_ipoint;
  43 static char *tk_trial;
  44 static struct textlist tk_tlist;
  45 #endif
  46
  47 static int cmd_left();
  48 static int cmd_right();
  49
  50 #if SPACES_IN_FILENAMES
  51 public char openquote = '"';
  52 public char closequote = '"';
  53 #endif
  54
  55 #if CMD_HISTORY
  56
  57 /* History file */
  58 #define HISTFILE_FIRST_LINE      ".less-history-file:"
  59 #define HISTFILE_SEARCH_SECTION  ".search"
  60 #define HISTFILE_SHELL_SECTION   ".shell"
  61
  62 /*
  63  * A mlist structure represents a command history.
  64  */
  65 struct mlist
  66 {
  67         struct mlist *next;
  68         struct mlist *prev;
  69         struct mlist *curr_mp;
  70         char *string;
  71         int modified;
  72 };
  73
  74 /*
  75  * These are the various command histories that exist.
  76  */
  77 struct mlist mlist_search =
  78         { &mlist_search,  &mlist_search,  &mlist_search,  NULL, 0 };
  79 public void * constant ml_search = (void *) &mlist_search;
  80
  81 struct mlist mlist_examine =
  82         { &mlist_examine, &mlist_examine, &mlist_examine, NULL, 0 };
  83 public void * constant ml_examine = (void *) &mlist_examine;
  84
  85 #if SHELL_ESCAPE || PIPEC
  86 struct mlist mlist_shell =
  87         { &mlist_shell,   &mlist_shell,   &mlist_shell,   NULL, 0 };
  88 public void * constant ml_shell = (void *) &mlist_shell;
  89 #endif
  90
  91 #else /* CMD_HISTORY */
  92
  93 /* If CMD_HISTORY is off, these are just flags. */
  94 public void * constant ml_search = (void *)1;
  95 public void * constant ml_examine = (void *)2;
  96 #if SHELL_ESCAPE || PIPEC
  97 public void * constant ml_shell = (void *)3;
  98 #endif
  99
 100 #endif /* CMD_HISTORY */
 101
 102 /*
 103  * History for the current command.
 104  */
 105 static struct mlist *curr_mlist = NULL;
 106 static int curr_cmdflags;
 107
 108 static char cmd_mbc_buf[MAX_UTF_CHAR_LEN];
 109 static int cmd_mbc_buf_len;
 110 static int cmd_mbc_buf_index;
 111
 112
 113 /*
 114  * Reset command buffer (to empty).
 115  */
 116         public void
 117 cmd_reset()
 118 {
 119         cp = cmdbuf;
 120         *cp = '\0';
 121         cmd_col = 0;
 122         cmd_offset = 0;
 123         literal = 0;
 124         cmd_mbc_buf_len = 0;
 125 }
 126
 127 /*
 128  * Clear command line.
 129  */
 130         public void
 131 clear_cmd()
 132 {
 133         cmd_col = prompt_col = 0;
 134         cmd_mbc_buf_len = 0;
 135 }
 136
 137 /*
 138  * Display a string, usually as a prompt for input into the command buffer.
 139  */
 140         public void
 141 cmd_putstr(s)
 142         char *s;
 143 {
 144         LWCHAR prev_ch = 0;
 145         LWCHAR ch;
 146         char *endline = s + strlen(s);
 147         while (*s != '\0')
 148         {
 149                 char *ns = s;
 150                 ch = step_char(&ns, +1, endline);
 151                 while (s < ns)
 152                         putchr(*s++);
 153                 if (!utf_mode)
 154                 {
 155                         cmd_col++;
 156                         prompt_col++;
 157                 } else if (!is_composing_char(ch) &&
 158                            !is_combining_char(prev_ch, ch))
 159                 {
 160                         int width = is_wide_char(ch) ? 2 : 1;
 161                         cmd_col += width;
 162                         prompt_col += width;
 163                 }
 164                 prev_ch = ch;
 165         }
 166 }
 167
 168 /*
 169  * How many characters are in the command buffer?
 170  */
 171         public int
 172 len_cmdbuf()
 173 {
 174         char *s = cmdbuf;
 175         char *endline = s + strlen(s);
 176         int len = 0;
 177
 178         while (*s != '\0')
 179         {
 180                 step_char(&s, +1, endline);
 181                 len++;
 182         }
 183         return (len);
 184 }
 185
 186 /*
 187  * Common part of cmd_step_right() and cmd_step_left().
 188  */
 189         static char *
 190 cmd_step_common(p, ch, len, pwidth, bswidth)
 191         char *p;
 192         LWCHAR ch;
 193         int len;
 194         int *pwidth;
 195         int *bswidth;
 196 {
 197         char *pr;
 198
 199         if (len == 1)
 200         {
 201                 pr = prchar((int) ch);
 202                 if (pwidth != NULL || bswidth != NULL)
 203                 {
 204                         int len = strlen(pr);
 205                         if (pwidth != NULL)
 206                                 *pwidth = len;
 207                         if (bswidth != NULL)
 208                                 *bswidth = len;
 209                 }
 210         } else
 211         {
 212                 pr = prutfchar(ch);
 213                 if (pwidth != NULL || bswidth != NULL)
 214                 {
 215                         if (is_composing_char(ch))
 216                         {
 217                                 if (pwidth != NULL)
 218                                         *pwidth = 0;
 219                                 if (bswidth != NULL)
 220                                         *bswidth = 0;
 221                         } else if (is_ubin_char(ch))
 222                         {
 223                                 int len = strlen(pr);
 224                                 if (pwidth != NULL)
 225                                         *pwidth = len;
 226                                 if (bswidth != NULL)
 227                                         *bswidth = len;
 228                         } else
 229                         {
 230                                 LWCHAR prev_ch = step_char(&p, -1, cmdbuf);
 231                                 if (is_combining_char(prev_ch, ch))
 232                                 {
 233                                         if (pwidth != NULL)
 234                                                 *pwidth = 0;
 235                                         if (bswidth != NULL)
 236                                                 *bswidth = 0;
 237                                 } else
 238                                 {
 239                                         if (pwidth != NULL)
 240                                                 *pwidth = is_wide_char(ch)
 241                                                         ?       2
 242                                                         :       1;
 243                                         if (bswidth != NULL)
 244                                                 *bswidth = 1;
 245                                 }
 246                         }
 247                 }
 248         }
 249
 250         return (pr);
 251 }
 252
 253 /*
 254  * Step a pointer one character right in the command buffer.
 255  */
 256         static char *
 257 cmd_step_right(pp, pwidth, bswidth)
 258         char **pp;
 259         int *pwidth;
 260         int *bswidth;
 261 {
 262         char *p = *pp;
 263         LWCHAR ch = step_char(pp, +1, p + strlen(p));
 264
 265         return cmd_step_common(p, ch, *pp - p, pwidth, bswidth);
 266 }
 267
 268 /*
 269  * Step a pointer one character left in the command buffer.
 270  */
 271         static char *
 272 cmd_step_left(pp, pwidth, bswidth)
 273         char **pp;
 274         int *pwidth;
 275         int *bswidth;
 276 {
 277         char *p = *pp;
 278         LWCHAR ch = step_char(pp, -1, cmdbuf);
 279
 280         return cmd_step_common(*pp, ch, p - *pp, pwidth, bswidth);
 281 }
 282
 283 /*
 284  * Repaint the line from cp onwards.
 285  * Then position the cursor just after the char old_cp (a pointer into cmdbuf).
 286  */
 287         static void
 288 cmd_repaint(old_cp)
 289         char *old_cp;
 290 {
 291         /*
 292          * Repaint the line from the current position.
 293          */
 294         clear_eol();
 295         while (*cp != '\0')
 296         {
 297                 char *np = cp;
 298                 int width;
 299                 char *pr = cmd_step_right(&np, &width, NULL);
 300                 if (cmd_col + width >= sc_width)
 301                         break;
 302                 cp = np;
 303                 putstr(pr);
 304                 cmd_col += width;
 305         }
 306         while (*cp != '\0')
 307         {
 308                 char *np = cp;
 309                 int width;
 310                 char *pr = cmd_step_right(&np, &width, NULL);
 311                 if (width > 0)
 312                         break;
 313                 cp = np;
 314                 putstr(pr);
 315         }
 316
 317         /*
 318          * Back up the cursor to the correct position.
 319          */
 320         while (cp > old_cp)
 321                 cmd_left();
 322 }
 323
 324 /*
 325  * Put the cursor at "home" (just after the prompt),
 326  * and set cp to the corresponding char in cmdbuf.
 327  */
 328         static void
 329 cmd_home()
 330 {
 331         while (cmd_col > prompt_col)
 332         {
 333                 int width, bswidth;
 334
 335                 cmd_step_left(&cp, &width, &bswidth);
 336                 while (bswidth-- > 0)
 337                         putbs();
 338                 cmd_col -= width;
 339         }
 340
 341         cp = &cmdbuf[cmd_offset];
 342 }
 343
 344 /*
 345  * Shift the cmdbuf display left a half-screen.
 346  */
 347         static void
 348 cmd_lshift()
 349 {
 350         char *s;
 351         char *save_cp;
 352         int cols;
 353
 354         /*
 355          * Start at the first displayed char, count how far to the
 356          * right we'd have to move to reach the center of the screen.
 357          */
 358         s = cmdbuf + cmd_offset;
 359         cols = 0;
 360         while (cols < (sc_width - prompt_col) / 2 && *s != '\0')
 361         {
 362                 int width;
 363                 cmd_step_right(&s, &width, NULL);
 364                 cols += width;
 365         }
 366         while (*s != '\0')
 367         {
 368                 int width;
 369                 char *ns = s;
 370                 cmd_step_right(&ns, &width, NULL);
 371                 if (width > 0)
 372                         break;
 373                 s = ns;
 374         }
 375
 376         cmd_offset = s - cmdbuf;
 377         save_cp = cp;
 378         cmd_home();
 379         cmd_repaint(save_cp);
 380 }
 381
 382 /*
 383  * Shift the cmdbuf display right a half-screen.
 384  */
 385         static void
 386 cmd_rshift()
 387 {
 388         char *s;
 389         char *save_cp;
 390         int cols;
 391
 392         /*
 393          * Start at the first displayed char, count how far to the
 394          * left we'd have to move to traverse a half-screen width
 395          * of displayed characters.
 396          */
 397         s = cmdbuf + cmd_offset;
 398         cols = 0;
 399         while (cols < (sc_width - prompt_col) / 2 && s > cmdbuf)
 400         {
 401                 int width;
 402                 cmd_step_left(&s, &width, NULL);
 403                 cols += width;
 404         }
 405
 406         cmd_offset = s - cmdbuf;
 407         save_cp = cp;
 408         cmd_home();
 409         cmd_repaint(save_cp);
 410 }
 411
 412 /*
 413  * Move cursor right one character.
 414  */
 415         static int
 416 cmd_right()
 417 {
 418         char *pr;
 419         char *ncp;
 420         int width;
 421
 422         if (*cp == '\0')
 423         {
 424                 /* Already at the end of the line. */
 425                 return (CC_OK);
 426         }
 427         ncp = cp;
 428         pr = cmd_step_right(&ncp, &width, NULL);
 429         if (cmd_col + width >= sc_width)
 430                 cmd_lshift();
 431         else if (cmd_col + width == sc_width - 1 && cp[1] != '\0')
 432                 cmd_lshift();
 433         cp = ncp;
 434         cmd_col += width;
 435         putstr(pr);
 436         while (*cp != '\0')
 437         {
 438                 pr = cmd_step_right(&ncp, &width, NULL);
 439                 if (width > 0)
 440                         break;
 441                 putstr(pr);
 442                 cp = ncp;
 443         }
 444         return (CC_OK);
 445 }
 446
 447 /*
 448  * Move cursor left one character.
 449  */
 450         static int
 451 cmd_left()
 452 {
 453         char *ncp;
 454         int width, bswidth;
 455
 456         if (cp <= cmdbuf)
 457         {
 458                 /* Already at the beginning of the line */
 459                 return (CC_OK);
 460         }
 461         ncp = cp;
 462         while (ncp > cmdbuf)
 463         {
 464                 cmd_step_left(&ncp, &width, &bswidth);
 465                 if (width > 0)
 466                         break;
 467         }
 468         if (cmd_col < prompt_col + width)
 469                 cmd_rshift();
 470         cp = ncp;
 471         cmd_col -= width;
 472         while (bswidth-- > 0)
 473                 putbs();
 474         return (CC_OK);
 475 }
 476
 477 /*
 478  * Insert a char into the command buffer, at the current position.
 479  */
 480         static int
 481 cmd_ichar(cs, clen)
 482         char *cs;
 483         int clen;
 484 {
 485         char *s;
 486
 487         if (strlen(cmdbuf) + clen >= sizeof(cmdbuf)-1)
 488         {
 489                 /* No room in the command buffer for another char. */
 490                 bell();
 491                 return (CC_ERROR);
 492         }
 493
 494         /*
 495          * Make room for the new character (shift the tail of the buffer right).
 496          */
 497         for (s = &cmdbuf[strlen(cmdbuf)];  s >= cp;  s--)
 498                 s[clen] = s[0];
 499         /*
 500          * Insert the character into the buffer.
 501          */
 502         for (s = cp;  s < cp + clen;  s++)
 503                 *s = *cs++;
 504         /*
 505          * Reprint the tail of the line from the inserted char.
 506          */
 507         cmd_repaint(cp);
 508         cmd_right();
 509         return (CC_OK);
 510 }
 511
 512 /*
 513  * Backspace in the command buffer.
 514  * Delete the char to the left of the cursor.
 515  */
 516         static int
 517 cmd_erase()
 518 {
 519         register char *s;
 520         int clen;
 521
 522         if (cp == cmdbuf)
 523         {
 524                 /*
 525                  * Backspace past beginning of the buffer:
 526                  * this usually means abort the command.
 527                  */
 528                 return (CC_QUIT);
 529         }
 530         /*
 531          * Move cursor left (to the char being erased).
 532          */
 533         s = cp;
 534         cmd_left();
 535         clen = s - cp;
 536
 537         /*
 538          * Remove the char from the buffer (shift the buffer left).
 539          */
 540         for (s = cp;  ;  s++)
 541         {
 542                 s[0] = s[clen];
 543                 if (s[0] == '\0')
 544                         break;
 545         }
 546
 547         /*
 548          * Repaint the buffer after the erased char.
 549          */
 550         cmd_repaint(cp);
 551
 552         /*
 553          * We say that erasing the entire command string causes us
 554          * to abort the current command, if CF_QUIT_ON_ERASE is set.
 555          */
 556         if ((curr_cmdflags & CF_QUIT_ON_ERASE) && cp == cmdbuf && *cp == '\0')
 557                 return (CC_QUIT);
 558         return (CC_OK);
 559 }
 560
 561 /*
 562  * Delete the char under the cursor.
 563  */
 564         static int
 565 cmd_delete()
 566 {
 567         if (*cp == '\0')
 568         {
 569                 /* At end of string; there is no char under the cursor. */
 570                 return (CC_OK);
 571         }
 572         /*
 573          * Move right, then use cmd_erase.
 574          */
 575         cmd_right();
 576         cmd_erase();
 577         return (CC_OK);
 578 }
 579
 580 /*
 581  * Delete the "word" to the left of the cursor.
 582  */
 583         static int
 584 cmd_werase()
 585 {
 586         if (cp > cmdbuf && cp[-1] == ' ')
 587         {
 588                 /*
 589                  * If the char left of cursor is a space,
 590                  * erase all the spaces left of cursor (to the first non-space).
 591                  */
 592                 while (cp > cmdbuf && cp[-1] == ' ')
 593                         (void) cmd_erase();
 594         } else
 595         {
 596                 /*
 597                  * If the char left of cursor is not a space,
 598                  * erase all the nonspaces left of cursor (the whole "word").
 599                  */
 600                 while (cp > cmdbuf && cp[-1] != ' ')
 601                         (void) cmd_erase();
 602         }
 603         return (CC_OK);
 604 }
 605
 606 /*
 607  * Delete the "word" under the cursor.
 608  */
 609         static int
 610 cmd_wdelete()
 611 {
 612         if (*cp == ' ')
 613         {
 614                 /*
 615                  * If the char under the cursor is a space,
 616                  * delete it and all the spaces right of cursor.
 617                  */
 618                 while (*cp == ' ')
 619                         (void) cmd_delete();
 620         } else
 621         {
 622                 /*
 623                  * If the char under the cursor is not a space,
 624                  * delete it and all nonspaces right of cursor (the whole word).
 625                  */
 626                 while (*cp != ' ' && *cp != '\0')
 627                         (void) cmd_delete();
 628         }
 629         return (CC_OK);
 630 }
 631
 632 /*
 633  * Delete all chars in the command buffer.
 634  */
 635         static int
 636 cmd_kill()
 637 {
 638         if (cmdbuf[0] == '\0')
 639         {
 640                 /* Buffer is already empty; abort the current command. */
 641                 return (CC_QUIT);
 642         }
 643         cmd_offset = 0;
 644         cmd_home();
 645         *cp = '\0';
 646         cmd_repaint(cp);
 647
 648         /*
 649          * We say that erasing the entire command string causes us
 650          * to abort the current command, if CF_QUIT_ON_ERASE is set.
 651          */
 652         if (curr_cmdflags & CF_QUIT_ON_ERASE)
 653                 return (CC_QUIT);
 654         return (CC_OK);
 655 }
 656
 657 /*
 658  * Select an mlist structure to be the current command history.
 659  */
 660         public void
 661 set_mlist(mlist, cmdflags)
 662         void *mlist;
 663         int cmdflags;
 664 {
 665         curr_mlist = (struct mlist *) mlist;
 666         curr_cmdflags = cmdflags;
 667
 668         /* Make sure the next up-arrow moves to the last string in the mlist. */
 669         if (curr_mlist != NULL)
 670                 curr_mlist->curr_mp = curr_mlist;
 671 }
 672
 673 #if CMD_HISTORY
 674 /*
 675  * Move up or down in the currently selected command history list.
 676  */
 677         static int
 678 cmd_updown(action)
 679         int action;
 680 {
 681         char *s;
 682
 683         if (curr_mlist == NULL)
 684         {
 685                 /*
 686                  * The current command has no history list.
 687                  */
 688                 bell();
 689                 return (CC_OK);
 690         }
 691         cmd_home();
 692         clear_eol();
 693         /*
 694          * Move curr_mp to the next/prev entry.
 695          */
 696         if (action == EC_UP)
 697                 curr_mlist->curr_mp = curr_mlist->curr_mp->prev;
 698         else
 699                 curr_mlist->curr_mp = curr_mlist->curr_mp->next;
 700         /*
 701          * Copy the entry into cmdbuf and echo it on the screen.
 702          */
 703         s = curr_mlist->curr_mp->string;
 704         if (s == NULL)
 705                 s = "";
 706         strcpy(cmdbuf, s);
 707         for (cp = cmdbuf;  *cp != '\0';  )
 708                 cmd_right();
 709         return (CC_OK);
 710 }
 711 #endif
 712
 713 /*
 714  * Add a string to a history list.
 715  */
 716         public void
 717 cmd_addhist(mlist, cmd)
 718         struct mlist *mlist;
 719         char *cmd;
 720 {
 721 #if CMD_HISTORY
 722         struct mlist *ml;
 723
 724         /*
 725          * Don't save a trivial command.
 726          */
 727         if (strlen(cmd) == 0)
 728                 return;
 729
 730         /*
 731          * Save the command unless it's a duplicate of the
 732          * last command in the history.
 733          */
 734         ml = mlist->prev;
 735         if (ml == mlist || strcmp(ml->string, cmd) != 0)
 736         {
 737                 /*
 738                  * Did not find command in history.
 739                  * Save the command and put it at the end of the history list.
 740                  */
 741                 ml = (struct mlist *) ecalloc(1, sizeof(struct mlist));
 742                 ml->string = save(cmd);
 743                 ml->next = mlist;
 744                 ml->prev = mlist->prev;
 745                 mlist->prev->next = ml;
 746                 mlist->prev = ml;
 747         }
 748         /*
 749          * Point to the cmd just after the just-accepted command.
 750          * Thus, an UPARROW will always retrieve the previous command.
 751          */
 752         mlist->curr_mp = ml->next;
 753 #endif
 754 }
 755
 756 /*
 757  * Accept the command in the command buffer.
 758  * Add it to the currently selected history list.
 759  */
 760         public void
 761 cmd_accept()
 762 {
 763 #if CMD_HISTORY
 764         /*
 765          * Nothing to do if there is no currently selected history list.
 766          */
 767         if (curr_mlist == NULL)
 768                 return;
 769         cmd_addhist(curr_mlist, cmdbuf);
 770         curr_mlist->modified = 1;
 771 #endif
 772 }
 773
 774 /*
 775  * Try to perform a line-edit function on the command buffer,
 776  * using a specified char as a line-editing command.
 777  * Returns:
 778  *      CC_PASS The char does not invoke a line edit function.
 779  *      CC_OK   Line edit function done.
 780  *      CC_QUIT The char requests the current command to be aborted.
 781  */
 782         static int
 783 cmd_edit(c)
 784         int c;
 785 {
 786         int action;
 787         int flags;
 788
 789 #if TAB_COMPLETE_FILENAME
 790 #define not_in_completion()     in_completion = 0
 791 #else
 792 #define not_in_completion()
 793 #endif
 794
 795         /*
 796          * See if the char is indeed a line-editing command.
 797          */
 798         flags = 0;
 799 #if CMD_HISTORY
 800         if (curr_mlist == NULL)
 801                 /*
 802                  * No current history; don't accept history manipulation cmds.
 803                  */
 804                 flags |= EC_NOHISTORY;
 805 #endif
 806 #if TAB_COMPLETE_FILENAME
 807         if (curr_mlist == ml_search)
 808                 /*
 809                  * In a search command; don't accept file-completion cmds.
 810                  */
 811                 flags |= EC_NOCOMPLETE;
 812 #endif
 813
 814         action = editchar(c, flags);
 815
 816         switch (action)
 817         {
 818         case EC_RIGHT:
 819                 not_in_completion();
 820                 return (cmd_right());
 821         case EC_LEFT:
 822                 not_in_completion();
 823                 return (cmd_left());
 824         case EC_W_RIGHT:
 825                 not_in_completion();
 826                 while (*cp != '\0' && *cp != ' ')
 827                         cmd_right();
 828                 while (*cp == ' ')
 829                         cmd_right();
 830                 return (CC_OK);
 831         case EC_W_LEFT:
 832                 not_in_completion();
 833                 while (cp > cmdbuf && cp[-1] == ' ')
 834                         cmd_left();
 835                 while (cp > cmdbuf && cp[-1] != ' ')
 836                         cmd_left();
 837                 return (CC_OK);
 838         case EC_HOME:
 839                 not_in_completion();
 840                 cmd_offset = 0;
 841                 cmd_home();
 842                 cmd_repaint(cp);
 843                 return (CC_OK);
 844         case EC_END:
 845                 not_in_completion();
 846                 while (*cp != '\0')
 847                         cmd_right();
 848                 return (CC_OK);
 849         case EC_INSERT:
 850                 not_in_completion();
 851                 return (CC_OK);
 852         case EC_BACKSPACE:
 853                 not_in_completion();
 854                 return (cmd_erase());
 855         case EC_LINEKILL:
 856                 not_in_completion();
 857                 return (cmd_kill());
 858         case EC_W_BACKSPACE:
 859                 not_in_completion();
 860                 return (cmd_werase());
 861         case EC_DELETE:
 862                 not_in_completion();
 863                 return (cmd_delete());
 864         case EC_W_DELETE:
 865                 not_in_completion();
 866                 return (cmd_wdelete());
 867         case EC_LITERAL:
 868                 literal = 1;
 869                 return (CC_OK);
 870 #if CMD_HISTORY
 871         case EC_UP:
 872         case EC_DOWN:
 873                 not_in_completion();
 874                 return (cmd_updown(action));
 875 #endif
 876 #if TAB_COMPLETE_FILENAME
 877         case EC_F_COMPLETE:
 878         case EC_B_COMPLETE:
 879         case EC_EXPAND:
 880                 return (cmd_complete(action));
 881 #endif
 882         case EC_NOACTION:
 883                 return (CC_OK);
 884         default:
 885                 not_in_completion();
 886                 return (CC_PASS);
 887         }
 888 }
 889
 890 #if TAB_COMPLETE_FILENAME
 891 /*
 892  * Insert a string into the command buffer, at the current position.
 893  */
 894         static int
 895 cmd_istr(str)
 896         char *str;
 897 {
 898         char *s;
 899         int action;
 900         char *endline = str + strlen(str);
 901
 902         for (s = str;  *s != '\0';  )
 903         {
 904                 char *os = s;
 905                 step_char(&s, +1, endline);
 906                 action = cmd_ichar(os, s - os);
 907                 if (action != CC_OK)
 908                 {
 909                         bell();
 910                         return (action);
 911                 }
 912         }
 913         return (CC_OK);
 914 }
 915
 916 /*
 917  * Find the beginning and end of the "current" word.
 918  * This is the word which the cursor (cp) is inside or at the end of.
 919  * Return pointer to the beginning of the word and put the
 920  * cursor at the end of the word.
 921  */
 922         static char *
 923 delimit_word()
 924 {
 925         char *word;
 926 #if SPACES_IN_FILENAMES
 927         char *p;
 928         int delim_quoted = 0;
 929         int meta_quoted = 0;
 930         char *esc = get_meta_escape();
 931         int esclen = strlen(esc);
 932 #endif
 933
 934         /*
 935          * Move cursor to end of word.
 936          */
 937         if (*cp != ' ' && *cp != '\0')
 938         {
 939                 /*
 940                  * Cursor is on a nonspace.
 941                  * Move cursor right to the next space.
 942                  */
 943                 while (*cp != ' ' && *cp != '\0')
 944                         cmd_right();
 945         } else if (cp > cmdbuf && cp[-1] != ' ')
 946         {
 947                 /*
 948                  * Cursor is on a space, and char to the left is a nonspace.
 949                  * We're already at the end of the word.
 950                  */
 951                 ;
 952 #if 0
 953         } else
 954         {
 955                 /*
 956                  * Cursor is on a space and char to the left is a space.
 957                  * Huh? There's no word here.
 958                  */
 959                 return (NULL);
 960 #endif
 961         }
 962         /*
 963          * Find the beginning of the word which the cursor is in.
 964          */
 965         if (cp == cmdbuf)
 966                 return (NULL);
 967 #if SPACES_IN_FILENAMES
 968         /*
 969          * If we have an unbalanced quote (that is, an open quote
 970          * without a corresponding close quote), we return everything
 971          * from the open quote, including spaces.
 972          */
 973         for (word = cmdbuf;  word < cp;  word++)
 974                 if (*word != ' ')
 975                         break;
 976         if (word >= cp)
 977                 return (cp);
 978         for (p = cmdbuf;  p < cp;  p++)
 979         {
 980                 if (meta_quoted)
 981                 {
 982                         meta_quoted = 0;
 983                 } else if (esclen > 0 && p + esclen < cp &&
 984                            strncmp(p, esc, esclen) == 0)
 985                 {
 986                         meta_quoted = 1;
 987                         p += esclen - 1;
 988                 } else if (delim_quoted)
 989                 {
 990                         if (*p == closequote)
 991                                 delim_quoted = 0;
 992                 } else /* (!delim_quoted) */
 993                 {
 994                         if (*p == openquote)
 995                                 delim_quoted = 1;
 996                         else if (*p == ' ')
 997                                 word = p+1;
 998                 }
 999         }
1000 #endif
1001         return (word);
1002 }
1003
1004 /*
1005  * Set things up to enter completion mode.
1006  * Expand the word under the cursor into a list of filenames
1007  * which start with that word, and set tk_text to that list.
1008  */
1009         static void
1010 init_compl()
1011 {
1012         char *word;
1013         char c;
1014
1015         /*
1016          * Get rid of any previous tk_text.
1017          */
1018         if (tk_text != NULL)
1019         {
1020                 free(tk_text);
1021                 tk_text = NULL;
1022         }
1023         /*
1024          * Find the original (uncompleted) word in the command buffer.
1025          */
1026         word = delimit_word();
1027         if (word == NULL)
1028                 return;
1029         /*
1030          * Set the insertion point to the point in the command buffer
1031          * where the original (uncompleted) word now sits.
1032          */
1033         tk_ipoint = word;
1034         /*
1035          * Save the original (uncompleted) word
1036          */
1037         if (tk_original != NULL)
1038                 free(tk_original);
1039         tk_original = (char *) ecalloc(cp-word+1, sizeof(char));
1040         strncpy(tk_original, word, cp-word);
1041         /*
1042          * Get the expanded filename.
1043          * This may result in a single filename, or
1044          * a blank-separated list of filenames.
1045          */
1046         c = *cp;
1047         *cp = '\0';
1048         if (*word != openquote)
1049         {
1050                 tk_text = fcomplete(word);
1051         } else
1052         {
1053                 char *qword = shell_quote(word+1);
1054                 if (qword == NULL)
1055                         tk_text = fcomplete(word+1);
1056                 else
1057                 {
1058                         tk_text = fcomplete(qword);
1059                         free(qword);
1060                 }
1061         }
1062         *cp = c;
1063 }
1064
1065 /*
1066  * Return the next word in the current completion list.
1067  */
1068         static char *
1069 next_compl(action, prev)
1070         int action;
1071         char *prev;
1072 {
1073         switch (action)
1074         {
1075         case EC_F_COMPLETE:
1076                 return (forw_textlist(&tk_tlist, prev));
1077         case EC_B_COMPLETE:
1078                 return (back_textlist(&tk_tlist, prev));
1079         }
1080         /* Cannot happen */
1081         return ("?");
1082 }
1083
1084 /*
1085  * Complete the filename before (or under) the cursor.
1086  * cmd_complete may be called multiple times.  The global in_completion
1087  * remembers whether this call is the first time (create the list),
1088  * or a subsequent time (step thru the list).
1089  */
1090         static int
1091 cmd_complete(action)
1092         int action;
1093 {
1094         char *s;
1095
1096         if (!in_completion || action == EC_EXPAND)
1097         {
1098                 /*
1099                  * Expand the word under the cursor and
1100                  * use the first word in the expansion
1101                  * (or the entire expansion if we're doing EC_EXPAND).
1102                  */
1103                 init_compl();
1104                 if (tk_text == NULL)
1105                 {
1106                         bell();
1107                         return (CC_OK);
1108                 }
1109                 if (action == EC_EXPAND)
1110                 {
1111                         /*
1112                          * Use the whole list.
1113                          */
1114                         tk_trial = tk_text;
1115                 } else
1116                 {
1117                         /*
1118                          * Use the first filename in the list.
1119                          */
1120                         in_completion = 1;
1121                         init_textlist(&tk_tlist, tk_text);
1122                         tk_trial = next_compl(action, (char*)NULL);
1123                 }
1124         } else
1125         {
1126                 /*
1127                  * We already have a completion list.
1128                  * Use the next/previous filename from the list.
1129                  */
1130                 tk_trial = next_compl(action, tk_trial);
1131         }
1132
1133         /*
1134          * Remove the original word, or the previous trial completion.
1135          */
1136         while (cp > tk_ipoint)
1137                 (void) cmd_erase();
1138
1139         if (tk_trial == NULL)
1140         {
1141                 /*
1142                  * There are no more trial completions.
1143                  * Insert the original (uncompleted) filename.
1144                  */
1145                 in_completion = 0;
1146                 if (cmd_istr(tk_original) != CC_OK)
1147                         goto fail;
1148         } else
1149         {
1150                 /*
1151                  * Insert trial completion.
1152                  */
1153                 if (cmd_istr(tk_trial) != CC_OK)
1154                         goto fail;
1155                 /*
1156                  * If it is a directory, append a slash.
1157                  */
1158                 if (is_dir(tk_trial))
1159                 {
1160                         if (cp > cmdbuf && cp[-1] == closequote)
1161                                 (void) cmd_erase();
1162                         s = lgetenv("LESSSEPARATOR");
1163                         if (s == NULL)
1164                                 s = PATHNAME_SEP;
1165                         if (cmd_istr(s) != CC_OK)
1166                                 goto fail;
1167                 }
1168         }
1169
1170         return (CC_OK);
1171
1172 fail:
1173         in_completion = 0;
1174         bell();
1175         return (CC_OK);
1176 }
1177
1178 #endif /* TAB_COMPLETE_FILENAME */
1179
1180 /*
1181  * Process a single character of a multi-character command, such as
1182  * a number, or the pattern of a search command.
1183  * Returns:
1184  *      CC_OK           The char was accepted.
1185  *      CC_QUIT         The char requests the command to be aborted.
1186  *      CC_ERROR        The char could not be accepted due to an error.
1187  */
1188         public int
1189 cmd_char(c)
1190         int c;
1191 {
1192         int action;
1193         int len;
1194
1195         if (!utf_mode)
1196         {
1197                 cmd_mbc_buf[0] = c;
1198                 len = 1;
1199         } else
1200         {
1201                 /* Perform strict validation in all possible cases.  */
1202                 if (cmd_mbc_buf_len == 0)
1203                 {
1204                  retry:
1205                         cmd_mbc_buf_index = 1;
1206                         *cmd_mbc_buf = c;
1207                         if (IS_ASCII_OCTET(c))
1208                                 cmd_mbc_buf_len = 1;
1209                         else if (IS_UTF8_LEAD(c))
1210                         {
1211                                 cmd_mbc_buf_len = utf_len(c);
1212                                 return (CC_OK);
1213                         } else
1214                         {
1215                                 /* UTF8_INVALID or stray UTF8_TRAIL */
1216                                 bell();
1217                                 return (CC_ERROR);
1218                         }
1219                 } else if (IS_UTF8_TRAIL(c))
1220                 {
1221                         cmd_mbc_buf[cmd_mbc_buf_index++] = c;
1222                         if (cmd_mbc_buf_index < cmd_mbc_buf_len)
1223                                 return (CC_OK);
1224                         if (!is_utf8_well_formed(cmd_mbc_buf))
1225                         {
1226                                 /* complete, but not well formed (non-shortest form), sequence */
1227                                 cmd_mbc_buf_len = 0;
1228                                 bell();
1229                                 return (CC_ERROR);
1230                         }
1231                 } else
1232                 {
1233                         /* Flush incomplete (truncated) sequence.  */
1234                         cmd_mbc_buf_len = 0;
1235                         bell();
1236                         /* Handle new char.  */
1237                         goto retry;
1238                 }
1239
1240                 len = cmd_mbc_buf_len;
1241                 cmd_mbc_buf_len = 0;
1242         }
1243
1244         if (literal)
1245         {
1246                 /*
1247                  * Insert the char, even if it is a line-editing char.
1248                  */
1249                 literal = 0;
1250                 return (cmd_ichar(cmd_mbc_buf, len));
1251         }
1252
1253         /*
1254          * See if it is a line-editing character.
1255          */
1256         if (in_mca() && len == 1)
1257         {
1258                 action = cmd_edit(c);
1259                 switch (action)
1260                 {
1261                 case CC_OK:
1262                 case CC_QUIT:
1263                         return (action);
1264                 case CC_PASS:
1265                         break;
1266                 }
1267         }
1268
1269         /*
1270          * Insert the char into the command buffer.
1271          */
1272         return (cmd_ichar(cmd_mbc_buf, len));
1273 }
1274
1275 /*
1276  * Return the number currently in the command buffer.
1277  */
1278         public LINENUM
1279 cmd_int(frac)
1280         long *frac;
1281 {
1282         char *p;
1283         LINENUM n = 0;
1284         int err;
1285
1286         for (p = cmdbuf;  *p >= '0' && *p <= '9';  p++)
1287                 n = (n * 10) + (*p - '0');
1288         *frac = 0;
1289         if (*p++ == '.')
1290         {
1291                 *frac = getfraction(&p, NULL, &err);
1292                 /* {{ do something if err is set? }} */
1293         }
1294         return (n);
1295 }
1296
1297 /*
1298  * Return a pointer to the command buffer.
1299  */
1300         public char *
1301 get_cmdbuf()
1302 {
1303         return (cmdbuf);
1304 }
1305
1306 /*
1307  * Return the last (most recent) string in the current command history.
1308  */
1309         public char *
1310 cmd_lastpattern()
1311 {
1312         if (curr_mlist == NULL)
1313                 return (NULL);
1314         return (curr_mlist->curr_mp->prev->string);
1315 }
1316
1317 #if CMD_HISTORY
1318 /*
1319  * Get the name of the history file.
1320  */
1321         static char *
1322 histfile_name()
1323 {
1324         char *home;
1325         char *name;
1326         int len;
1327
1328         /* See if filename is explicitly specified by $LESSHISTFILE. */
1329         name = lgetenv("LESSHISTFILE");
1330         if (name != NULL && *name != '\0')
1331         {
1332                 if (strcmp(name, "-") == 0 || strcmp(name, "/dev/null") == 0)
1333                         /* $LESSHISTFILE == "-" means don't use a history file. */
1334                         return (NULL);
1335                 return (save(name));
1336         }
1337
1338         /* Otherwise, file is in $HOME. */
1339         home = lgetenv("HOME");
1340         if (home == NULL || *home == '\0')
1341         {
1342 #if OS2
1343                 home = lgetenv("INIT");
1344                 if (home == NULL || *home == '\0')
1345 #endif
1346                         return (NULL);
1347         }
1348         len = strlen(home) + strlen(LESSHISTFILE) + 2;
1349         name = (char *) ecalloc(len, sizeof(char));
1350         SNPRINTF2(name, len, "%s/%s", home, LESSHISTFILE);
1351         return (name);
1352 }
1353 #endif /* CMD_HISTORY */
1354
1355 /*
1356  * Initialize history from a .lesshist file.
1357  */
1358         public void
1359 init_cmdhist()
1360 {
1361 #if CMD_HISTORY
1362         struct mlist *ml = NULL;
1363         char line[CMDBUF_SIZE];
1364         char *filename;
1365         FILE *f;
1366         char *p;
1367
1368         filename = histfile_name();
1369         if (filename == NULL)
1370                 return;
1371         f = fopen(filename, "r");
1372         free(filename);
1373         if (f == NULL)
1374                 return;
1375         if (fgets(line, sizeof(line), f) == NULL ||
1376             strncmp(line, HISTFILE_FIRST_LINE, strlen(HISTFILE_FIRST_LINE)) != 0)
1377         {
1378                 fclose(f);
1379                 return;
1380         }
1381         while (fgets(line, sizeof(line), f) != NULL)
1382         {
1383                 for (p = line;  *p != '\0';  p++)
1384                 {
1385                         if (*p == '\n' || *p == '\r')
1386                         {
1387                                 *p = '\0';
1388                                 break;
1389                         }
1390                 }
1391                 if (strcmp(line, HISTFILE_SEARCH_SECTION) == 0)
1392                         ml = &mlist_search;
1393                 else if (strcmp(line, HISTFILE_SHELL_SECTION) == 0)
1394                 {
1395 #if SHELL_ESCAPE || PIPEC
1396                         ml = &mlist_shell;
1397 #else
1398                         ml = NULL;
1399 #endif
1400                 } else if (*line == '"')
1401                 {
1402                         if (ml != NULL)
1403                                 cmd_addhist(ml, line+1);
1404                 }
1405         }
1406         fclose(f);
1407 #endif /* CMD_HISTORY */
1408 }
1409
1410 /*
1411  *
1412  */
1413 #if CMD_HISTORY
1414         static void
1415 save_mlist(ml, f)
1416         struct mlist *ml;
1417         FILE *f;
1418 {
1419         int histsize = 0;
1420         int n;
1421         char *s;
1422
1423         s = lgetenv("LESSHISTSIZE");
1424         if (s != NULL)
1425                 histsize = atoi(s);
1426         if (histsize == 0)
1427                 histsize = 100;
1428
1429         ml = ml->prev;
1430         for (n = 0;  n < histsize;  n++)
1431         {
1432                 if (ml->string == NULL)
1433                         break;
1434                 ml = ml->prev;
1435         }
1436         for (ml = ml->next;  ml->string != NULL;  ml = ml->next)
1437                 fprintf(f, "\"%s\n", ml->string);
1438 }
1439 #endif /* CMD_HISTORY */
1440
1441 /*
1442  *
1443  */
1444         public void
1445 save_cmdhist()
1446 {
1447 #if CMD_HISTORY
1448         char *filename;
1449         FILE *f;
1450         int modified = 0;
1451
1452         filename = histfile_name();
1453         if (filename == NULL)
1454                 return;
1455         if (mlist_search.modified)
1456                 modified = 1;
1457 #if SHELL_ESCAPE || PIPEC
1458         if (mlist_shell.modified)
1459                 modified = 1;
1460 #endif
1461         if (!modified)
1462                 return;
1463         f = fopen(filename, "w");
1464         free(filename);
1465         if (f == NULL)
1466                 return;
1467 #if HAVE_FCHMOD
1468         /* Make history file readable only by owner. */
1469         fchmod(fileno(f), 0600);
1470 #endif
1471
1472         fprintf(f, "%s\n", HISTFILE_FIRST_LINE);
1473
1474         fprintf(f, "%s\n", HISTFILE_SEARCH_SECTION);
1475         save_mlist(&mlist_search, f);
1476
1477 #if SHELL_ESCAPE || PIPEC
1478         fprintf(f, "%s\n", HISTFILE_SHELL_SECTION);
1479         save_mlist(&mlist_shell, f);
1480 #endif
1481
1482         fclose(f);
1483 #endif /* CMD_HISTORY */
1484 }