xref: /openbsd/usr.bin/less/command.c (revision 3d8817e4)
1 /*
2  * Copyright (C) 1984-2002  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  * User-level command processor.
14  */
15 
16 #include "less.h"
17 #if MSDOS_COMPILER==WIN32C
18 #include <windows.h>
19 #endif
20 #include "position.h"
21 #include "option.h"
22 #include "cmd.h"
23 
24 extern int erase_char, kill_char;
25 extern int sigs;
26 extern int quit_at_eof;
27 extern int quit_if_one_screen;
28 extern int squished;
29 extern int hit_eof;
30 extern int sc_width;
31 extern int sc_height;
32 extern int swindow;
33 extern int jump_sline;
34 extern int quitting;
35 extern int wscroll;
36 extern int nohelp;
37 extern int top_scroll;
38 extern int ignore_eoi;
39 extern int secure;
40 extern int hshift;
41 extern int show_attn;
42 extern char *every_first_cmd;
43 extern char *curr_altfilename;
44 extern char version[];
45 extern struct scrpos initial_scrpos;
46 extern IFILE curr_ifile;
47 extern void constant *ml_search;
48 extern void constant *ml_examine;
49 #if SHELL_ESCAPE || PIPEC
50 extern void constant *ml_shell;
51 #endif
52 #if EDITOR
53 extern char *editor;
54 extern char *editproto;
55 #endif
56 extern int screen_trashed;	/* The screen has been overwritten */
57 extern int shift_count;
58 extern int be_helpful;
59 
60 static char ungot[UNGOT_SIZE];
61 static char *ungotp = NULL;
62 #if SHELL_ESCAPE
63 static char *shellcmd = NULL;	/* For holding last shell command for "!!" */
64 #endif
65 static int mca;			/* The multicharacter command (action) */
66 static int search_type;		/* The previous type of search */
67 static LINENUM number;		/* The number typed by the user */
68 static char optchar;
69 static int optflag;
70 static int optgetname;
71 static POSITION bottompos;
72 static char *help_prompt;
73 #if PIPEC
74 static char pipec;
75 #endif
76 
77 static void multi_search();
78 
79 /*
80  * Move the cursor to lower left before executing a command.
81  * This looks nicer if the command takes a long time before
82  * updating the screen.
83  */
84 	static void
85 cmd_exec()
86 {
87 	clear_attn();
88 	lower_left();
89 	flush();
90 }
91 
92 /*
93  * Set up the display to start a new multi-character command.
94  */
95 	static void
96 start_mca(action, prompt, mlist, cmdflags)
97 	int action;
98 	char *prompt;
99 	void *mlist;
100 	int cmdflags;
101 {
102 	mca = action;
103 	clear_cmd();
104 	cmd_putstr(prompt);
105 	set_mlist(mlist, cmdflags);
106 }
107 
108 	public int
109 in_mca()
110 {
111 	return (mca != 0 && mca != A_PREFIX);
112 }
113 
114 /*
115  * Set up the display to start a new search command.
116  */
117 	static void
118 mca_search()
119 {
120 	if (search_type & SRCH_FORW)
121 		mca = A_F_SEARCH;
122 	else
123 		mca = A_B_SEARCH;
124 
125 	clear_cmd();
126 
127 	if (search_type & SRCH_NO_MATCH)
128 		cmd_putstr("Non-match ");
129 	if (search_type & SRCH_FIRST_FILE)
130 		cmd_putstr("First-file ");
131 	if (search_type & SRCH_PAST_EOF)
132 		cmd_putstr("EOF-ignore ");
133 	if (search_type & SRCH_NO_MOVE)
134 		cmd_putstr("Keep-pos ");
135 	if (search_type & SRCH_NO_REGEX)
136 		cmd_putstr("Regex-off ");
137 
138 	if (search_type & SRCH_FORW)
139 		cmd_putstr("/");
140 	else
141 		cmd_putstr("?");
142 	set_mlist(ml_search, 0);
143 }
144 
145 /*
146  * Set up the display to start a new toggle-option command.
147  */
148 	static void
149 mca_opt_toggle()
150 {
151 	int no_prompt;
152 	int flag;
153 	char *dash;
154 
155 	no_prompt = (optflag & OPT_NO_PROMPT);
156 	flag = (optflag & ~OPT_NO_PROMPT);
157 	dash = (flag == OPT_NO_TOGGLE) ? "_" : "-";
158 
159 	mca = A_OPT_TOGGLE;
160 	clear_cmd();
161 	cmd_putstr(dash);
162 #if GNU_OPTIONS
163 	if (optgetname)
164 		cmd_putstr(dash);
165 #endif
166 	if (no_prompt)
167 		cmd_putstr("(P)");
168 	switch (flag)
169 	{
170 	case OPT_UNSET:
171 		cmd_putstr("+");
172 		break;
173 	case OPT_SET:
174 		cmd_putstr("!");
175 		break;
176 	}
177 	set_mlist(NULL, 0);
178 }
179 
180 /*
181  * Execute a multicharacter command.
182  */
183 	static void
184 exec_mca()
185 {
186 	register char *cbuf;
187 
188 	cmd_exec();
189 	cbuf = get_cmdbuf();
190 
191 	switch (mca)
192 	{
193 	case A_F_SEARCH:
194 	case A_B_SEARCH:
195 		multi_search(cbuf, (int) number);
196 		break;
197 	case A_FIRSTCMD:
198 		/*
199 		 * Skip leading spaces or + signs in the string.
200 		 */
201 		while (*cbuf == '+' || *cbuf == ' ')
202 			cbuf++;
203 		if (every_first_cmd != NULL)
204 			free(every_first_cmd);
205 		if (*cbuf == '\0')
206 			every_first_cmd = NULL;
207 		else
208 			every_first_cmd = save(cbuf);
209 		break;
210 	case A_OPT_TOGGLE:
211 		toggle_option(optchar, cbuf, optflag);
212 		optchar = '\0';
213 		break;
214 	case A_F_BRACKET:
215 		match_brac(cbuf[0], cbuf[1], 1, (int) number);
216 		break;
217 	case A_B_BRACKET:
218 		match_brac(cbuf[1], cbuf[0], 0, (int) number);
219 		break;
220 #if EXAMINE
221 	case A_EXAMINE:
222 		if (secure)
223 			break;
224 		edit_list(cbuf);
225 #if TAGS
226 		/* If tag structure is loaded then clean it up. */
227 		cleantags();
228 #endif
229 		break;
230 #endif
231 #if SHELL_ESCAPE
232 	case A_SHELL:
233 		/*
234 		 * !! just uses whatever is in shellcmd.
235 		 * Otherwise, copy cmdbuf to shellcmd,
236 		 * expanding any special characters ("%" or "#").
237 		 */
238 		if (*cbuf != '!')
239 		{
240 			if (shellcmd != NULL)
241 				free(shellcmd);
242 			shellcmd = fexpand(cbuf);
243 		}
244 
245 		if (secure)
246 			break;
247 		if (shellcmd == NULL)
248 			lsystem("", "!done");
249 		else
250 			lsystem(shellcmd, "!done");
251 		break;
252 #endif
253 #if PIPEC
254 	case A_PIPE:
255 		if (secure)
256 			break;
257 		(void) pipe_mark(pipec, cbuf);
258 		error("|done", NULL_PARG);
259 		break;
260 #endif
261 	}
262 }
263 
264 /*
265  * Add a character to a multi-character command.
266  */
267 	static int
268 mca_char(c)
269 	int c;
270 {
271 	char *p;
272 	int flag;
273 	char buf[3];
274 	PARG parg;
275 
276 	switch (mca)
277 	{
278 	case 0:
279 		/*
280 		 * Not in a multicharacter command.
281 		 */
282 		return (NO_MCA);
283 
284 	case A_PREFIX:
285 		/*
286 		 * In the prefix of a command.
287 		 * This not considered a multichar command
288 		 * (even tho it uses cmdbuf, etc.).
289 		 * It is handled in the commands() switch.
290 		 */
291 		return (NO_MCA);
292 
293 	case A_DIGIT:
294 		/*
295 		 * Entering digits of a number.
296 		 * Terminated by a non-digit.
297 		 */
298 		if ((c < '0' || c > '9') &&
299 		  editchar(c, EC_PEEK|EC_NOHISTORY|EC_NOCOMPLETE|EC_NORIGHTLEFT) == A_INVALID)
300 		{
301 			/*
302 			 * Not part of the number.
303 			 * Treat as a normal command character.
304 			 */
305 			number = cmd_int();
306 			mca = 0;
307 			cmd_accept();
308 			return (NO_MCA);
309 		}
310 		break;
311 
312 	case A_OPT_TOGGLE:
313 		/*
314 		 * Special case for the TOGGLE_OPTION command.
315 		 * If the option letter which was entered is a
316 		 * single-char option, execute the command immediately,
317 		 * so user doesn't have to hit RETURN.
318 		 * If the first char is + or -, this indicates
319 		 * OPT_UNSET or OPT_SET respectively, instead of OPT_TOGGLE.
320 		 * "--" begins inputting a long option name.
321 		 */
322 		if (optchar == '\0' && len_cmdbuf() == 0)
323 		{
324 			flag = (optflag & ~OPT_NO_PROMPT);
325 #if GNU_OPTIONS
326 			if (flag == OPT_NO_TOGGLE)
327 			{
328 				switch (c)
329 				{
330 				case '_':
331 					/* "__" = long option name. */
332 					optgetname = TRUE;
333 					mca_opt_toggle();
334 					return (MCA_MORE);
335 				}
336 			} else
337 #endif
338 			{
339 				switch (c)
340 				{
341 				case '+':
342 					/* "-+" = UNSET. */
343 					optflag = (flag == OPT_UNSET) ?
344 						OPT_TOGGLE : OPT_UNSET;
345 					mca_opt_toggle();
346 					return (MCA_MORE);
347 				case '!':
348 					/* "-!" = SET */
349 					optflag = (flag == OPT_SET) ?
350 						OPT_TOGGLE : OPT_SET;
351 					mca_opt_toggle();
352 					return (MCA_MORE);
353 				case CONTROL('P'):
354 					optflag ^= OPT_NO_PROMPT;
355 					mca_opt_toggle();
356 					return (MCA_MORE);
357 #if GNU_OPTIONS
358 				case '-':
359 					/* "--" = long option name. */
360 					optgetname = TRUE;
361 					mca_opt_toggle();
362 					return (MCA_MORE);
363 #endif
364 				}
365 			}
366 		}
367 #if GNU_OPTIONS
368 		if (optgetname)
369 		{
370 			/*
371 			 * We're getting a long option name.
372 			 * See if we've matched an option name yet.
373 			 * If so, display the complete name and stop
374 			 * accepting chars until user hits RETURN.
375 			 */
376 			struct loption *o;
377 			char *oname;
378 			int lc;
379 
380 			if (c == '\n' || c == '\r')
381 			{
382 				/*
383 				 * When the user hits RETURN, make sure
384 				 * we've matched an option name, then
385 				 * pretend he just entered the equivalent
386 				 * option letter.
387 				 */
388 				if (optchar == '\0')
389 				{
390 					parg.p_string = get_cmdbuf();
391 					error("There is no --%s option", &parg);
392 					return (MCA_DONE);
393 				}
394 				optgetname = FALSE;
395 				cmd_reset();
396 				c = optchar;
397 			} else
398 			{
399 				if (optchar != '\0')
400 				{
401 					/*
402 					 * Already have a match for the name.
403 					 * Don't accept anything but erase/kill.
404 					 */
405 					if (c == erase_char || c == kill_char)
406 						return (MCA_DONE);
407 					return (MCA_MORE);
408 				}
409 				/*
410 				 * Add char to cmd buffer and try to match
411 				 * the option name.
412 				 */
413 				if (cmd_char(c) == CC_QUIT)
414 					return (MCA_DONE);
415 				p = get_cmdbuf();
416 				lc = islower(p[0]);
417 				o = findopt_name(&p, &oname, NULL);
418 				if (o != NULL)
419 				{
420 					/*
421 					 * Got a match.
422 					 * Remember the option letter and
423 					 * display the full option name.
424 					 */
425 					optchar = o->oletter;
426 					if (!lc && islower(optchar))
427 						optchar = toupper(optchar);
428 					cmd_reset();
429 					mca_opt_toggle();
430 					for (p = oname;  *p != '\0';  p++)
431 					{
432 						c = *p;
433 						if (!lc && islower(c))
434 							c = toupper(c);
435 						if (cmd_char(c) != CC_OK)
436 							return (MCA_DONE);
437 					}
438 				}
439 				return (MCA_MORE);
440 			}
441 		} else
442 #endif
443 		{
444 			if (c == erase_char || c == kill_char)
445 				break;
446 			if (optchar != '\0')
447 				/* We already have the option letter. */
448 				break;
449 		}
450 
451 		optchar = c;
452 		if ((optflag & ~OPT_NO_PROMPT) != OPT_TOGGLE ||
453 		    single_char_option(c))
454 		{
455 			toggle_option(c, "", optflag);
456 			return (MCA_DONE);
457 		}
458 		/*
459 		 * Display a prompt appropriate for the option letter.
460 		 */
461 		if ((p = opt_prompt(c)) == NULL)
462 		{
463 			buf[0] = '-';
464 			buf[1] = c;
465 			buf[2] = '\0';
466 			p = buf;
467 		}
468 		start_mca(A_OPT_TOGGLE, p, (void*)NULL, 0);
469 		return (MCA_MORE);
470 
471 	case A_F_SEARCH:
472 	case A_B_SEARCH:
473 		/*
474 		 * Special case for search commands.
475 		 * Certain characters as the first char of
476 		 * the pattern have special meaning:
477 		 *	!  Toggle the NO_MATCH flag
478 		 *	*  Toggle the PAST_EOF flag
479 		 *	@  Toggle the FIRST_FILE flag
480 		 */
481 		if (len_cmdbuf() > 0)
482 			/*
483 			 * Only works for the first char of the pattern.
484 			 */
485 			break;
486 
487 		flag = 0;
488 		switch (c)
489 		{
490 		case CONTROL('E'): /* ignore END of file */
491 		case '*':
492 			flag = SRCH_PAST_EOF;
493 			break;
494 		case CONTROL('F'): /* FIRST file */
495 		case '@':
496 			flag = SRCH_FIRST_FILE;
497 			break;
498 		case CONTROL('K'): /* KEEP position */
499 			flag = SRCH_NO_MOVE;
500 			break;
501 		case CONTROL('R'): /* Don't use REGULAR EXPRESSIONS */
502 			flag = SRCH_NO_REGEX;
503 			break;
504 		case CONTROL('N'): /* NOT match */
505 		case '!':
506 			flag = SRCH_NO_MATCH;
507 			break;
508 		}
509 		if (flag != 0)
510 		{
511 			search_type ^= flag;
512 			mca_search();
513 			return (MCA_MORE);
514 		}
515 		break;
516 	}
517 
518 	/*
519 	 * Any other multicharacter command
520 	 * is terminated by a newline.
521 	 */
522 	if (c == '\n' || c == '\r')
523 	{
524 		/*
525 		 * Execute the command.
526 		 */
527 		exec_mca();
528 		return (MCA_DONE);
529 	}
530 
531 	/*
532 	 * Append the char to the command buffer.
533 	 */
534 	if (cmd_char(c) == CC_QUIT)
535 		/*
536 		 * Abort the multi-char command.
537 		 */
538 		return (MCA_DONE);
539 
540 	if ((mca == A_F_BRACKET || mca == A_B_BRACKET) && len_cmdbuf() >= 2)
541 	{
542 		/*
543 		 * Special case for the bracket-matching commands.
544 		 * Execute the command after getting exactly two
545 		 * characters from the user.
546 		 */
547 		exec_mca();
548 		return (MCA_DONE);
549 	}
550 
551 	/*
552 	 * Need another character.
553 	 */
554 	return (MCA_MORE);
555 }
556 
557 /*
558  * Make sure the screen is displayed.
559  */
560 	static void
561 make_display()
562 {
563 	/*
564 	 * If nothing is displayed yet, display starting from initial_scrpos.
565 	 */
566 	if (empty_screen())
567 	{
568 		if (initial_scrpos.pos == NULL_POSITION)
569 			/*
570 			 * {{ Maybe this should be:
571 			 *    jump_loc(ch_zero(), jump_sline);
572 			 *    but this behavior seems rather unexpected
573 			 *    on the first screen. }}
574 			 */
575 			jump_loc(ch_zero(), 1);
576 		else
577 			jump_loc(initial_scrpos.pos, initial_scrpos.ln);
578 	} else if (screen_trashed)
579 	{
580 		int save_top_scroll;
581 		save_top_scroll = top_scroll;
582 		top_scroll = 1;
583 		repaint();
584 		top_scroll = save_top_scroll;
585 	}
586 }
587 
588 /*
589  * Display the appropriate prompt.
590  */
591 	static void
592 prompt()
593 {
594 	register char *p;
595 
596 	if (ungotp != NULL && ungotp > ungot)
597 	{
598 		/*
599 		 * No prompt necessary if commands are from
600 		 * ungotten chars rather than from the user.
601 		 */
602 		return;
603 	}
604 
605 	/*
606 	 * Make sure the screen is displayed.
607 	 */
608 	make_display();
609 	bottompos = position(BOTTOM_PLUS_ONE);
610 
611 	/*
612 	 * If the -E flag is set and we've hit EOF on the last file, quit.
613 	 */
614 	if ((quit_at_eof == OPT_ONPLUS || quit_if_one_screen) &&
615 	    hit_eof && next_ifile(curr_ifile) == NULL_IFILE)
616 		quit(QUIT_OK);
617 	quit_if_one_screen = FALSE;
618 #if 0 /* This doesn't work well because some "te"s clear the screen. */
619 	/*
620 	 * If the -e flag is set and we've hit EOF on the last file,
621 	 * and the file is squished (shorter than the screen), quit.
622 	 */
623 	if (quit_at_eof && squished &&
624 	    next_ifile(curr_ifile) == NULL_IFILE)
625 		quit(QUIT_OK);
626 #endif
627 
628 	/*
629 	 * Select the proper prompt and display it.
630 	 */
631 	clear_cmd();
632 	p = help_prompt ? help_prompt : pr_string();
633 	if (p == NULL)
634 		putchr(':');
635 	else
636 	{
637 		so_enter();
638 		putstr(p);
639 		if (be_helpful && !help_prompt && strlen(p) + 40 < sc_width)
640 			putstr(" [Press space to continue, 'q' to quit.]");
641 		so_exit();
642 	}
643 	help_prompt = NULL;
644 }
645 
646 /*
647  * Display the less version message.
648  */
649 	public void
650 dispversion()
651 {
652 	PARG parg;
653 
654 	parg.p_string = version;
655 	error("less %s", &parg);
656 }
657 
658 /*
659  * Get command character.
660  * The character normally comes from the keyboard,
661  * but may come from ungotten characters
662  * (characters previously given to ungetcc or ungetsc).
663  */
664 	public int
665 getcc()
666 {
667 	if (ungotp == NULL)
668 		/*
669 		 * Normal case: no ungotten chars, so get one from the user.
670 		 */
671 		return (getchr());
672 
673 	if (ungotp > ungot)
674 		/*
675 		 * Return the next ungotten char.
676 		 */
677 		return (*--ungotp);
678 
679 	/*
680 	 * We have just run out of ungotten chars.
681 	 */
682 	ungotp = NULL;
683 	if (len_cmdbuf() == 0 || !empty_screen())
684 		return (getchr());
685 	/*
686 	 * Command is incomplete, so try to complete it.
687 	 */
688 	switch (mca)
689 	{
690 	case A_DIGIT:
691 		/*
692 		 * We have a number but no command.  Treat as #g.
693 		 */
694 		return ('g');
695 
696 	case A_F_SEARCH:
697 	case A_B_SEARCH:
698 		/*
699 		 * We have "/string" but no newline.  Add the \n.
700 		 */
701 		return ('\n');
702 
703 	default:
704 		/*
705 		 * Some other incomplete command.  Let user complete it.
706 		 */
707 		return (getchr());
708 	}
709 }
710 
711 /*
712  * "Unget" a command character.
713  * The next getcc() will return this character.
714  */
715 	public void
716 ungetcc(c)
717 	int c;
718 {
719 	if (ungotp == NULL)
720 		ungotp = ungot;
721 	if (ungotp >= ungot + sizeof(ungot))
722 	{
723 		error("ungetcc overflow", NULL_PARG);
724 		quit(QUIT_ERROR);
725 	}
726 	*ungotp++ = c;
727 }
728 
729 /*
730  * Unget a whole string of command characters.
731  * The next sequence of getcc()'s will return this string.
732  */
733 	public void
734 ungetsc(s)
735 	char *s;
736 {
737 	register char *p;
738 
739 	for (p = s + strlen(s) - 1;  p >= s;  p--)
740 		ungetcc(*p);
741 }
742 
743 /*
744  * Search for a pattern, possibly in multiple files.
745  * If SRCH_FIRST_FILE is set, begin searching at the first file.
746  * If SRCH_PAST_EOF is set, continue the search thru multiple files.
747  */
748 	static void
749 multi_search(pattern, n)
750 	char *pattern;
751 	int n;
752 {
753 	register int nomore;
754 	IFILE save_ifile;
755 	int changed_file;
756 
757 	changed_file = 0;
758 	save_ifile = save_curr_ifile();
759 
760 	if (search_type & SRCH_FIRST_FILE)
761 	{
762 		/*
763 		 * Start at the first (or last) file
764 		 * in the command line list.
765 		 */
766 		if (search_type & SRCH_FORW)
767 			nomore = edit_first();
768 		else
769 			nomore = edit_last();
770 		if (nomore)
771 		{
772 			unsave_ifile(save_ifile);
773 			return;
774 		}
775 		changed_file = 1;
776 		search_type &= ~SRCH_FIRST_FILE;
777 	}
778 
779 	for (;;)
780 	{
781 		n = search(search_type, pattern, n);
782 		/*
783 		 * The SRCH_NO_MOVE flag doesn't "stick": it gets cleared
784 		 * after being used once.  This allows "n" to work after
785 		 * using a /@@ search.
786 		 */
787 		search_type &= ~SRCH_NO_MOVE;
788 		if (n == 0)
789 		{
790 			/*
791 			 * Found it.
792 			 */
793 			unsave_ifile(save_ifile);
794 			return;
795 		}
796 
797 		if (n < 0)
798 			/*
799 			 * Some kind of error in the search.
800 			 * Error message has been printed by search().
801 			 */
802 			break;
803 
804 		if ((search_type & SRCH_PAST_EOF) == 0)
805 			/*
806 			 * We didn't find a match, but we're
807 			 * supposed to search only one file.
808 			 */
809 			break;
810 		/*
811 		 * Move on to the next file.
812 		 */
813 		if (search_type & SRCH_FORW)
814 			nomore = edit_next(1);
815 		else
816 			nomore = edit_prev(1);
817 		if (nomore)
818 			break;
819 		changed_file = 1;
820 	}
821 
822 	/*
823 	 * Didn't find it.
824 	 * Print an error message if we haven't already.
825 	 */
826 	if (n > 0)
827 		error("Pattern not found", NULL_PARG);
828 
829 	if (changed_file)
830 	{
831 		/*
832 		 * Restore the file we were originally viewing.
833 		 */
834 		reedit_ifile(save_ifile);
835 	}
836 }
837 
838 /*
839  * Main command processor.
840  * Accept and execute commands until a quit command.
841  */
842 	public void
843 commands()
844 {
845 	register int c;
846 	register int action;
847 	register char *cbuf;
848 	int newaction;
849 	int save_search_type;
850 	char *extra;
851 	char tbuf[2];
852 	PARG parg;
853 	IFILE old_ifile;
854 	IFILE new_ifile;
855 	char *tagfile;
856 
857 	search_type = SRCH_FORW;
858 	wscroll = (sc_height + 1) / 2;
859 	newaction = A_NOACTION;
860 
861 	for (;;)
862 	{
863 		mca = 0;
864 		cmd_accept();
865 		number = 0;
866 		optchar = '\0';
867 
868 		/*
869 		 * See if any signals need processing.
870 		 */
871 		if (sigs)
872 		{
873 			psignals();
874 			if (quitting)
875 				quit(QUIT_SAVED_STATUS);
876 		}
877 
878 		/*
879 		 * See if window size changed, for systems that don't
880 		 * generate SIGWINCH.
881 		 */
882 		check_winch();
883 
884 		/*
885 		 * Display prompt and accept a character.
886 		 */
887 		cmd_reset();
888 		prompt();
889 		if (sigs)
890 			continue;
891 		if (newaction == A_NOACTION)
892 			c = getcc();
893 
894 	again:
895 		if (sigs)
896 			continue;
897 
898 		if (newaction != A_NOACTION)
899 		{
900 			action = newaction;
901 			newaction = A_NOACTION;
902 		} else
903 		{
904 			/*
905 			 * If we are in a multicharacter command, call mca_char.
906 			 * Otherwise we call fcmd_decode to determine the
907 			 * action to be performed.
908 			 */
909 			if (mca)
910 				switch (mca_char(c))
911 				{
912 				case MCA_MORE:
913 					/*
914 					 * Need another character.
915 					 */
916 					c = getcc();
917 					goto again;
918 				case MCA_DONE:
919 					/*
920 					 * Command has been handled by mca_char.
921 					 * Start clean with a prompt.
922 					 */
923 					continue;
924 				case NO_MCA:
925 					/*
926 					 * Not a multi-char command
927 					 * (at least, not anymore).
928 					 */
929 					break;
930 				}
931 
932 			/*
933 			 * Decode the command character and decide what to do.
934 			 */
935 			if (mca)
936 			{
937 				/*
938 				 * We're in a multichar command.
939 				 * Add the character to the command buffer
940 				 * and display it on the screen.
941 				 * If the user backspaces past the start
942 				 * of the line, abort the command.
943 				 */
944 				if (cmd_char(c) == CC_QUIT || len_cmdbuf() == 0)
945 					continue;
946 				cbuf = get_cmdbuf();
947 			} else
948 			{
949 				/*
950 				 * Don't use cmd_char if we're starting fresh
951 				 * at the beginning of a command, because we
952 				 * don't want to echo the command until we know
953 				 * it is a multichar command.  We also don't
954 				 * want erase_char/kill_char to be treated
955 				 * as line editing characters.
956 				 */
957 				tbuf[0] = c;
958 				tbuf[1] = '\0';
959 				cbuf = tbuf;
960 			}
961 			extra = NULL;
962 			action = fcmd_decode(cbuf, &extra);
963 			/*
964 			 * If an "extra" string was returned,
965 			 * process it as a string of command characters.
966 			 */
967 			if (extra != NULL)
968 				ungetsc(extra);
969 		}
970 		/*
971 		 * Clear the cmdbuf string.
972 		 * (But not if we're in the prefix of a command,
973 		 * because the partial command string is kept there.)
974 		 */
975 		if (action != A_PREFIX)
976 			cmd_reset();
977 
978 		switch (action)
979 		{
980 		case A_DIGIT:
981 			/*
982 			 * First digit of a number.
983 			 */
984 			start_mca(A_DIGIT, ":", (void*)NULL, CF_QUIT_ON_ERASE);
985 			goto again;
986 
987 		case A_F_WINDOW:
988 			/*
989 			 * Forward one window (and set the window size).
990 			 */
991 			if (number > 0)
992 				swindow = (int) number;
993 			/* FALLTHRU */
994 		case A_F_SCREEN:
995 			/*
996 			 * Forward one screen.
997 			 */
998 			if (number <= 0)
999 				number = get_swindow();
1000 			cmd_exec();
1001 			if (show_attn)
1002 				set_attnpos(bottompos);
1003 			forward((int) number, 0, 1);
1004 			break;
1005 
1006 		case A_B_WINDOW:
1007 			/*
1008 			 * Backward one window (and set the window size).
1009 			 */
1010 			if (number > 0)
1011 				swindow = (int) number;
1012 			/* FALLTHRU */
1013 		case A_B_SCREEN:
1014 			/*
1015 			 * Backward one screen.
1016 			 */
1017 			if (number <= 0)
1018 				number = get_swindow();
1019 			cmd_exec();
1020 			backward((int) number, 0, 1);
1021 			break;
1022 
1023 		case A_F_LINE:
1024 			/*
1025 			 * Forward N (default 1) line.
1026 			 */
1027 			if (number <= 0)
1028 				number = 1;
1029 			cmd_exec();
1030 			if (show_attn == OPT_ONPLUS && number > 1)
1031 				set_attnpos(bottompos);
1032 			forward((int) number, 0, 0);
1033 			break;
1034 
1035 		case A_B_LINE:
1036 			/*
1037 			 * Backward N (default 1) line.
1038 			 */
1039 			if (number <= 0)
1040 				number = 1;
1041 			cmd_exec();
1042 			backward((int) number, 0, 0);
1043 			break;
1044 
1045 		case A_FF_LINE:
1046 			/*
1047 			 * Force forward N (default 1) line.
1048 			 */
1049 			if (number <= 0)
1050 				number = 1;
1051 			cmd_exec();
1052 			if (show_attn == OPT_ONPLUS && number > 1)
1053 				set_attnpos(bottompos);
1054 			forward((int) number, 1, 0);
1055 			break;
1056 
1057 		case A_BF_LINE:
1058 			/*
1059 			 * Force backward N (default 1) line.
1060 			 */
1061 			if (number <= 0)
1062 				number = 1;
1063 			cmd_exec();
1064 			backward((int) number, 1, 0);
1065 			break;
1066 
1067 		case A_FF_SCREEN:
1068 			/*
1069 			 * Force forward one screen.
1070 			 */
1071 			if (number <= 0)
1072 				number = get_swindow();
1073 			cmd_exec();
1074 			if (show_attn == OPT_ONPLUS)
1075 				set_attnpos(bottompos);
1076 			forward((int) number, 1, 0);
1077 			break;
1078 
1079 		case A_F_FOREVER:
1080 			/*
1081 			 * Forward forever, ignoring EOF.
1082 			 */
1083 			cmd_exec();
1084 			jump_forw();
1085 			ignore_eoi = 1;
1086 			hit_eof = 0;
1087 			while (!sigs)
1088 				forward(1, 0, 0);
1089 			ignore_eoi = 0;
1090 			/*
1091 			 * This gets us back in "F mode" after processing
1092 			 * a non-abort signal (e.g. window-change).
1093 			 */
1094 			if (sigs && !ABORT_SIGS())
1095 				newaction = A_F_FOREVER;
1096 			break;
1097 
1098 		case A_F_SCROLL:
1099 			/*
1100 			 * Forward N lines
1101 			 * (default same as last 'd' or 'u' command).
1102 			 */
1103 			if (number > 0)
1104 				wscroll = (int) number;
1105 			cmd_exec();
1106 			if (show_attn == OPT_ONPLUS)
1107 				set_attnpos(bottompos);
1108 			forward(wscroll, 0, 0);
1109 			break;
1110 
1111 		case A_B_SCROLL:
1112 			/*
1113 			 * Forward N lines
1114 			 * (default same as last 'd' or 'u' command).
1115 			 */
1116 			if (number > 0)
1117 				wscroll = (int) number;
1118 			cmd_exec();
1119 			backward(wscroll, 0, 0);
1120 			break;
1121 
1122 		case A_FREPAINT:
1123 			/*
1124 			 * Flush buffers, then repaint screen.
1125 			 * Don't flush the buffers on a pipe!
1126 			 */
1127 			if (ch_getflags() & CH_CANSEEK)
1128 			{
1129 				ch_flush();
1130 				clr_linenum();
1131 #if HILITE_SEARCH
1132 				clr_hilite();
1133 #endif
1134 			}
1135 			/* FALLTHRU */
1136 		case A_REPAINT:
1137 			/*
1138 			 * Repaint screen.
1139 			 */
1140 			cmd_exec();
1141 			repaint();
1142 			break;
1143 
1144 		case A_GOLINE:
1145 			/*
1146 			 * Go to line N, default beginning of file.
1147 			 */
1148 			if (number <= 0)
1149 				number = 1;
1150 			cmd_exec();
1151 			jump_back(number);
1152 			break;
1153 
1154 		case A_PERCENT:
1155 			/*
1156 			 * Go to a specified percentage into the file.
1157 			 */
1158 			if (number < 0)
1159 				number = 0;
1160 			if (number > 100)
1161 				number = 100;
1162 			cmd_exec();
1163 			jump_percent((int) number);
1164 			break;
1165 
1166 		case A_GOEND:
1167 			/*
1168 			 * Go to line N, default end of file.
1169 			 */
1170 			cmd_exec();
1171 			if (number <= 0)
1172 				jump_forw();
1173 			else
1174 				jump_back(number);
1175 			break;
1176 
1177 		case A_GOPOS:
1178 			/*
1179 			 * Go to a specified byte position in the file.
1180 			 */
1181 			cmd_exec();
1182 			if (number < 0)
1183 				number = 0;
1184 			jump_line_loc((POSITION) number, jump_sline);
1185 			break;
1186 
1187 		case A_STAT:
1188 			/*
1189 			 * Print file name, etc.
1190 			 */
1191 			cmd_exec();
1192 			parg.p_string = eq_message();
1193 			error("%s", &parg);
1194 			break;
1195 
1196 		case A_VERSION:
1197 			/*
1198 			 * Print version number, without the "@(#)".
1199 			 */
1200 			cmd_exec();
1201 			dispversion();
1202 			break;
1203 
1204 		case A_QUIT:
1205 			/*
1206 			 * Exit.
1207 			 */
1208 			if (extra != NULL)
1209 				quit(*extra);
1210 			quit(QUIT_OK);
1211 			break;
1212 
1213 /*
1214  * Define abbreviation for a commonly used sequence below.
1215  */
1216 #define	DO_SEARCH()	if (number <= 0) number = 1;	\
1217 			mca_search();			\
1218 			cmd_exec();			\
1219 			multi_search((char *)NULL, (int) number);
1220 
1221 
1222 		case A_F_SEARCH:
1223 			/*
1224 			 * Search forward for a pattern.
1225 			 * Get the first char of the pattern.
1226 			 */
1227 			search_type = SRCH_FORW;
1228 			if (number <= 0)
1229 				number = 1;
1230 			mca_search();
1231 			c = getcc();
1232 			goto again;
1233 
1234 		case A_B_SEARCH:
1235 			/*
1236 			 * Search backward for a pattern.
1237 			 * Get the first char of the pattern.
1238 			 */
1239 			search_type = SRCH_BACK;
1240 			if (number <= 0)
1241 				number = 1;
1242 			mca_search();
1243 			c = getcc();
1244 			goto again;
1245 
1246 		case A_AGAIN_SEARCH:
1247 			/*
1248 			 * Repeat previous search.
1249 			 */
1250 			DO_SEARCH();
1251 			break;
1252 
1253 		case A_T_AGAIN_SEARCH:
1254 			/*
1255 			 * Repeat previous search, multiple files.
1256 			 */
1257 			search_type |= SRCH_PAST_EOF;
1258 			DO_SEARCH();
1259 			break;
1260 
1261 		case A_REVERSE_SEARCH:
1262 			/*
1263 			 * Repeat previous search, in reverse direction.
1264 			 */
1265 			save_search_type = search_type;
1266 			search_type = SRCH_REVERSE(search_type);
1267 			DO_SEARCH();
1268 			search_type = save_search_type;
1269 			break;
1270 
1271 		case A_T_REVERSE_SEARCH:
1272 			/*
1273 			 * Repeat previous search,
1274 			 * multiple files in reverse direction.
1275 			 */
1276 			save_search_type = search_type;
1277 			search_type = SRCH_REVERSE(search_type);
1278 			search_type |= SRCH_PAST_EOF;
1279 			DO_SEARCH();
1280 			search_type = save_search_type;
1281 			break;
1282 
1283 		case A_UNDO_SEARCH:
1284 			undo_search();
1285 			break;
1286 
1287 		case A_HELP:
1288 			/*
1289 			 * Help.
1290 			 */
1291 			if (nohelp)
1292 			{
1293 				bell();
1294 				break;
1295 			}
1296 			clear_bot();
1297 			putstr(" help");
1298 			cmd_exec();
1299 			help(0);
1300 			break;
1301 
1302 		case A_EXAMINE:
1303 #if EXAMINE
1304 			/*
1305 			 * Edit a new file.  Get the filename.
1306 			 */
1307 			if (secure)
1308 			{
1309 				error("Command not available", NULL_PARG);
1310 				break;
1311 			}
1312 			start_mca(A_EXAMINE, "Examine: ", ml_examine, 0);
1313 			c = getcc();
1314 			goto again;
1315 #else
1316 			error("Command not available", NULL_PARG);
1317 			break;
1318 #endif
1319 
1320 		case A_VISUAL:
1321 			/*
1322 			 * Invoke an editor on the input file.
1323 			 */
1324 #if EDITOR
1325 			if (secure)
1326 			{
1327 				error("Command not available", NULL_PARG);
1328 				break;
1329 			}
1330 			if (strcmp(get_filename(curr_ifile), "-") == 0)
1331 			{
1332 				error("Cannot edit standard input", NULL_PARG);
1333 				break;
1334 			}
1335 			if (curr_altfilename != NULL)
1336 			{
1337 				error("Cannot edit file processed with LESSOPEN",
1338 					NULL_PARG);
1339 				break;
1340 			}
1341 			start_mca(A_SHELL, "!", ml_shell, 0);
1342 			/*
1343 			 * Expand the editor prototype string
1344 			 * and pass it to the system to execute.
1345 			 * (Make sure the screen is displayed so the
1346 			 * expansion of "+%lm" works.)
1347 			 */
1348 			make_display();
1349 			cmd_exec();
1350 			lsystem(pr_expand(editproto, 0), (char*)NULL);
1351 			break;
1352 #else
1353 			error("Command not available", NULL_PARG);
1354 			break;
1355 #endif
1356 
1357 		case A_NEXT_FILE:
1358 			/*
1359 			 * Examine next file.
1360 			 */
1361 #if TAGS
1362 			if (ntags())
1363 			{
1364 				error("No next file", NULL_PARG);
1365 				break;
1366 			}
1367 #endif
1368 			if (number <= 0)
1369 				number = 1;
1370 			if (edit_next((int) number))
1371 			{
1372 				if (quit_at_eof && hit_eof)
1373 					quit(QUIT_OK);
1374 				parg.p_string = (number > 1) ? "(N-th) " : "";
1375 				error("No %snext file", &parg);
1376 			}
1377 			break;
1378 
1379 		case A_PREV_FILE:
1380 			/*
1381 			 * Examine previous file.
1382 			 */
1383 #if TAGS
1384 			if (ntags())
1385 			{
1386 				error("No previous file", NULL_PARG);
1387 				break;
1388 			}
1389 #endif
1390 			if (number <= 0)
1391 				number = 1;
1392 			if (edit_prev((int) number))
1393 			{
1394 				parg.p_string = (number > 1) ? "(N-th) " : "";
1395 				error("No %sprevious file", &parg);
1396 			}
1397 			break;
1398 
1399 		case A_NEXT_TAG:
1400 #if TAGS
1401 			if (number <= 0)
1402 				number = 1;
1403 			tagfile = nexttag((int) number);
1404 			if (tagfile == NULL)
1405 			{
1406 				error("No next tag", NULL_PARG);
1407 				break;
1408 			}
1409 			if (edit(tagfile) == 0)
1410 			{
1411 				POSITION pos = tagsearch();
1412 				if (pos != NULL_POSITION)
1413 					jump_loc(pos, jump_sline);
1414 			}
1415 #else
1416 			error("Command not available", NULL_PARG);
1417 #endif
1418 			break;
1419 
1420 		case A_PREV_TAG:
1421 #if TAGS
1422 			if (number <= 0)
1423 				number = 1;
1424 			tagfile = prevtag((int) number);
1425 			if (tagfile == NULL)
1426 			{
1427 				error("No previous tag", NULL_PARG);
1428 				break;
1429 			}
1430 			if (edit(tagfile) == 0)
1431 			{
1432 				POSITION pos = tagsearch();
1433 				if (pos != NULL_POSITION)
1434 					jump_loc(pos, jump_sline);
1435 			}
1436 #else
1437 			error("Command not available", NULL_PARG);
1438 #endif
1439 			break;
1440 
1441 		case A_INDEX_FILE:
1442 			/*
1443 			 * Examine a particular file.
1444 			 */
1445 			if (number <= 0)
1446 				number = 1;
1447 			if (edit_index((int) number))
1448 				error("No such file", NULL_PARG);
1449 			break;
1450 
1451 		case A_REMOVE_FILE:
1452 			old_ifile = curr_ifile;
1453 			new_ifile = getoff_ifile(curr_ifile);
1454 			if (new_ifile == NULL_IFILE)
1455 			{
1456 				bell();
1457 				break;
1458 			}
1459 			if (edit_ifile(new_ifile) != 0)
1460 			{
1461 				reedit_ifile(old_ifile);
1462 				break;
1463 			}
1464 			del_ifile(old_ifile);
1465 			break;
1466 
1467 		case A_OPT_TOGGLE:
1468 			optflag = OPT_TOGGLE;
1469 			optgetname = FALSE;
1470 			mca_opt_toggle();
1471 			c = getcc();
1472 			goto again;
1473 
1474 		case A_DISP_OPTION:
1475 			/*
1476 			 * Report a flag setting.
1477 			 */
1478 			optflag = OPT_NO_TOGGLE;
1479 			optgetname = FALSE;
1480 			mca_opt_toggle();
1481 			c = getcc();
1482 			goto again;
1483 
1484 		case A_FIRSTCMD:
1485 			/*
1486 			 * Set an initial command for new files.
1487 			 */
1488 			start_mca(A_FIRSTCMD, "+", (void*)NULL, 0);
1489 			c = getcc();
1490 			goto again;
1491 
1492 		case A_SHELL:
1493 			/*
1494 			 * Shell escape.
1495 			 */
1496 #if SHELL_ESCAPE
1497 			if (secure)
1498 			{
1499 				error("Command not available", NULL_PARG);
1500 				break;
1501 			}
1502 			start_mca(A_SHELL, "!", ml_shell, 0);
1503 			c = getcc();
1504 			goto again;
1505 #else
1506 			error("Command not available", NULL_PARG);
1507 			break;
1508 #endif
1509 
1510 		case A_SETMARK:
1511 			/*
1512 			 * Set a mark.
1513 			 */
1514 			start_mca(A_SETMARK, "mark: ", (void*)NULL, 0);
1515 			c = getcc();
1516 			if (c == erase_char || c == kill_char ||
1517 			    c == '\n' || c == '\r')
1518 				break;
1519 			setmark(c);
1520 			break;
1521 
1522 		case A_GOMARK:
1523 			/*
1524 			 * Go to a mark.
1525 			 */
1526 			start_mca(A_GOMARK, "goto mark: ", (void*)NULL, 0);
1527 			c = getcc();
1528 			if (c == erase_char || c == kill_char ||
1529 			    c == '\n' || c == '\r')
1530 				break;
1531 			gomark(c);
1532 			break;
1533 
1534 		case A_PIPE:
1535 #if PIPEC
1536 			if (secure)
1537 			{
1538 				error("Command not available", NULL_PARG);
1539 				break;
1540 			}
1541 			start_mca(A_PIPE, "|mark: ", (void*)NULL, 0);
1542 			c = getcc();
1543 			if (c == erase_char || c == kill_char)
1544 				break;
1545 			if (c == '\n' || c == '\r')
1546 				c = '.';
1547 			if (badmark(c))
1548 				break;
1549 			pipec = c;
1550 			start_mca(A_PIPE, "!", ml_shell, 0);
1551 			c = getcc();
1552 			goto again;
1553 #else
1554 			error("Command not available", NULL_PARG);
1555 			break;
1556 #endif
1557 
1558 		case A_B_BRACKET:
1559 		case A_F_BRACKET:
1560 			start_mca(action, "Brackets: ", (void*)NULL, 0);
1561 			c = getcc();
1562 			goto again;
1563 
1564 		case A_LSHIFT:
1565 			if (number > 0)
1566 				shift_count = number;
1567 			else
1568 				number = (shift_count > 0) ?
1569 					shift_count : sc_width / 2;
1570 			if (number > hshift)
1571 				number = hshift;
1572 			hshift -= number;
1573 			screen_trashed = 1;
1574 			break;
1575 
1576 		case A_RSHIFT:
1577 			if (number > 0)
1578 				shift_count = number;
1579 			else
1580 				number = (shift_count > 0) ?
1581 					shift_count : sc_width / 2;
1582 			hshift += number;
1583 			screen_trashed = 1;
1584 			break;
1585 
1586 		case A_PREFIX:
1587 			/*
1588 			 * The command is incomplete (more chars are needed).
1589 			 * Display the current char, so the user knows
1590 			 * what's going on, and get another character.
1591 			 */
1592 			if (mca != A_PREFIX)
1593 			{
1594 				cmd_reset();
1595 				start_mca(A_PREFIX, " ", (void*)NULL,
1596 					CF_QUIT_ON_ERASE);
1597 				(void) cmd_char(c);
1598 			}
1599 			c = getcc();
1600 			goto again;
1601 
1602 		case A_NOACTION:
1603 			break;
1604 
1605 		default:
1606 			if (be_helpful)
1607 				help_prompt = "[Press 'h' for instructions.]";
1608 			else
1609 				bell();
1610 			break;
1611 		}
1612 	}
1613 }
1614