xref: /openbsd-src/usr.bin/less/command.c (revision 46035553bfdd96e63c94e32da0210227ec2e3cf1)
1 /*
2  * Copyright (C) 1984-2012  Mark Nudelman
3  * Modified for use with illumos by Garrett D'Amore.
4  * Copyright 2014 Garrett D'Amore <garrett@damore.org>
5  *
6  * You may distribute under the terms of either the GNU General Public
7  * License or the Less License, as specified in the README file.
8  *
9  * For more information, see the README file.
10  */
11 
12 /*
13  * User-level command processor.
14  */
15 
16 #include "cmd.h"
17 #include "less.h"
18 #include "option.h"
19 #include "position.h"
20 
21 extern int erase_char, erase2_char, kill_char;
22 extern int quit_if_one_screen;
23 extern int less_is_more;
24 extern int squished;
25 extern int sc_width;
26 extern int sc_height;
27 extern int swindow;
28 extern int jump_sline;
29 extern int quitting;
30 extern int wscroll;
31 extern int top_scroll;
32 extern int ignore_eoi;
33 extern int secure;
34 extern int hshift;
35 extern int show_attn;
36 extern off_t highest_hilite;
37 extern char *every_first_cmd;
38 extern char *curr_altfilename;
39 extern char version[];
40 extern struct scrpos initial_scrpos;
41 extern IFILE curr_ifile;
42 extern void *ml_search;
43 extern void *ml_examine;
44 extern void *ml_shell;
45 extern char *editor;
46 extern char *editproto;
47 extern int screen_trashed;	/* The screen has been overwritten */
48 extern int shift_count;
49 extern int oldbot;
50 extern int forw_prompt;
51 
52 static int mca;			/* The multicharacter command (action) */
53 static int search_type;		/* The previous type of search */
54 static off_t number;		/* The number typed by the user */
55 static long fraction;		/* The fractional part of the number */
56 static struct loption *curropt;
57 static int opt_lower;
58 static int optflag;
59 static int optgetname;
60 static off_t bottompos;
61 static int save_hshift;
62 static int pipec;
63 
64 struct ungot {
65 	struct ungot *ug_next;
66 	int ug_char;
67 };
68 static struct ungot *ungot = NULL;
69 static int unget_end = 0;
70 
71 static void multi_search(char *, int);
72 
73 /*
74  * Move the cursor to start of prompt line before executing a command.
75  * This looks nicer if the command takes a long time before
76  * updating the screen.
77  */
78 static void
79 cmd_exec(void)
80 {
81 	clear_attn();
82 	clear_bot();
83 	flush(0);
84 }
85 
86 /*
87  * Set up the display to start a new multi-character command.
88  */
89 static void
90 start_mca(int action, const char *prompt, void *mlist, int cmdflags)
91 {
92 	mca = action;
93 	clear_bot();
94 	clear_cmd();
95 	cmd_putstr((char *)prompt);
96 	set_mlist(mlist, cmdflags);
97 }
98 
99 int
100 in_mca(void)
101 {
102 	return (mca != 0 && mca != A_PREFIX);
103 }
104 
105 /*
106  * Set up the display to start a new search command.
107  */
108 static void
109 mca_search(void)
110 {
111 	if (search_type & SRCH_FILTER)
112 		mca = A_FILTER;
113 	else if (search_type & SRCH_FORW)
114 		mca = A_F_SEARCH;
115 	else
116 		mca = A_B_SEARCH;
117 
118 	clear_bot();
119 	clear_cmd();
120 
121 	if (search_type & SRCH_NO_MATCH)
122 		cmd_putstr("Non-match ");
123 	if (search_type & SRCH_FIRST_FILE)
124 		cmd_putstr("First-file ");
125 	if (search_type & SRCH_PAST_EOF)
126 		cmd_putstr("EOF-ignore ");
127 	if (search_type & SRCH_NO_MOVE)
128 		cmd_putstr("Keep-pos ");
129 	if (search_type & SRCH_NO_REGEX)
130 		cmd_putstr("Regex-off ");
131 
132 	if (search_type & SRCH_FILTER)
133 		cmd_putstr("&/");
134 	else if (search_type & SRCH_FORW)
135 		cmd_putstr("/");
136 	else
137 		cmd_putstr("?");
138 	set_mlist(ml_search, 0);
139 }
140 
141 /*
142  * Set up the display to start a new toggle-option command.
143  */
144 static void
145 mca_opt_toggle(void)
146 {
147 	int no_prompt;
148 	int flag;
149 	char *dash;
150 
151 	no_prompt = (optflag & OPT_NO_PROMPT);
152 	flag = (optflag & ~OPT_NO_PROMPT);
153 	dash = (flag == OPT_NO_TOGGLE) ? "_" : "-";
154 
155 	mca = A_OPT_TOGGLE;
156 	clear_bot();
157 	clear_cmd();
158 	cmd_putstr(dash);
159 	if (optgetname)
160 		cmd_putstr(dash);
161 	if (no_prompt)
162 		cmd_putstr("(P)");
163 	switch (flag) {
164 	case OPT_UNSET:
165 		cmd_putstr("+");
166 		break;
167 	case OPT_SET:
168 		cmd_putstr("!");
169 		break;
170 	}
171 	set_mlist(NULL, 0);
172 }
173 
174 /*
175  * Execute a multicharacter command.
176  */
177 static void
178 exec_mca(void)
179 {
180 	char *cbuf;
181 
182 	cmd_exec();
183 	cbuf = get_cmdbuf();
184 
185 	switch (mca) {
186 	case A_F_SEARCH:
187 	case A_B_SEARCH:
188 		multi_search(cbuf, (int)number);
189 		break;
190 	case A_FILTER:
191 		search_type ^= SRCH_NO_MATCH;
192 		set_filter_pattern(cbuf, search_type);
193 		break;
194 	case A_FIRSTCMD:
195 		/*
196 		 * Skip leading spaces or + signs in the string.
197 		 */
198 		while (*cbuf == '+' || *cbuf == ' ')
199 			cbuf++;
200 		free(every_first_cmd);
201 		if (*cbuf == '\0')
202 			every_first_cmd = NULL;
203 		else
204 			every_first_cmd = estrdup(cbuf);
205 		break;
206 	case A_OPT_TOGGLE:
207 		toggle_option(curropt, opt_lower, cbuf, optflag);
208 		curropt = NULL;
209 		break;
210 	case A_F_BRACKET:
211 		match_brac(cbuf[0], cbuf[1], 1, (int)number);
212 		break;
213 	case A_B_BRACKET:
214 		match_brac(cbuf[1], cbuf[0], 0, (int)number);
215 		break;
216 	case A_EXAMINE:
217 		if (secure)
218 			break;
219 
220 		/* POSIX behavior, but possibly generally useful */
221 		if (strlen(cbuf) == 0) {
222 			reopen_curr_ifile();
223 			jump_back(1);
224 			break;
225 		}
226 		/* POSIX behavior - probably not generally useful */
227 		if (less_is_more && (strcmp(cbuf, "#") == 0)) {
228 			if (ntags()) {
229 				error("No previous file", NULL);
230 				break;
231 			}
232 			if (edit_prev(1)) {
233 				error("No previous file", NULL);
234 			} else {
235 				jump_back(1);
236 			}
237 			break;
238 		}
239 		edit_list(cbuf);
240 		/* If tag structure is loaded then clean it up. */
241 		cleantags();
242 		break;
243 	case A_PIPE:
244 		if (secure)
245 			break;
246 		(void) pipe_mark(pipec, cbuf);
247 		error("|done", NULL);
248 		break;
249 	}
250 }
251 
252 /*
253  * Is a character an erase or kill char?
254  */
255 static int
256 is_erase_char(int c)
257 {
258 	return (c == erase_char || c == erase2_char || c == kill_char);
259 }
260 
261 /*
262  * Handle the first char of an option (after the initial dash).
263  */
264 static int
265 mca_opt_first_char(int c)
266 {
267 	int flag = (optflag & ~OPT_NO_PROMPT);
268 	if (flag == OPT_NO_TOGGLE) {
269 		switch (c) {
270 		case '_':
271 			/* "__" = long option name. */
272 			optgetname = TRUE;
273 			mca_opt_toggle();
274 			return (MCA_MORE);
275 		}
276 	} else {
277 		switch (c) {
278 		case '+':
279 			/* "-+" = UNSET. */
280 			optflag = (flag == OPT_UNSET) ? OPT_TOGGLE : OPT_UNSET;
281 			mca_opt_toggle();
282 			return (MCA_MORE);
283 		case '!':
284 			/* "-!" = SET */
285 			optflag = (flag == OPT_SET) ? OPT_TOGGLE : OPT_SET;
286 			mca_opt_toggle();
287 			return (MCA_MORE);
288 		case CONTROL('P'):
289 			optflag ^= OPT_NO_PROMPT;
290 			mca_opt_toggle();
291 			return (MCA_MORE);
292 		case '-':
293 			/* "--" = long option name. */
294 			optgetname = TRUE;
295 			mca_opt_toggle();
296 			return (MCA_MORE);
297 		}
298 	}
299 	/* Char was not handled here. */
300 	return (NO_MCA);
301 }
302 
303 /*
304  * Add a char to a long option name.
305  * See if we've got a match for an option name yet.
306  * If so, display the complete name and stop
307  * accepting chars until user hits RETURN.
308  */
309 static int
310 mca_opt_nonfirst_char(int c)
311 {
312 	char *p;
313 	char *oname;
314 
315 	if (curropt != NULL) {
316 		/*
317 		 * Already have a match for the name.
318 		 * Don't accept anything but erase/kill.
319 		 */
320 		if (is_erase_char(c))
321 			return (MCA_DONE);
322 		return (MCA_MORE);
323 	}
324 	/*
325 	 * Add char to cmd buffer and try to match
326 	 * the option name.
327 	 */
328 	if (cmd_char(c) == CC_QUIT)
329 		return (MCA_DONE);
330 	p = get_cmdbuf();
331 	opt_lower = islower(p[0]);
332 	curropt = findopt_name(&p, &oname, NULL);
333 	if (curropt != NULL) {
334 		/*
335 		 * Got a match.
336 		 * Remember the option and
337 		 * display the full option name.
338 		 */
339 		cmd_reset();
340 		mca_opt_toggle();
341 		for (p = oname; *p != '\0'; p++) {
342 			c = *p;
343 			if (!opt_lower && islower(c))
344 				c = toupper(c);
345 			if (cmd_char(c) != CC_OK)
346 				return (MCA_DONE);
347 		}
348 	}
349 	return (MCA_MORE);
350 }
351 
352 /*
353  * Handle a char of an option toggle command.
354  */
355 static int
356 mca_opt_char(int c)
357 {
358 	PARG parg;
359 
360 	/*
361 	 * This may be a short option (single char),
362 	 * or one char of a long option name,
363 	 * or one char of the option parameter.
364 	 */
365 	if (curropt == NULL && len_cmdbuf() == 0) {
366 		int ret = mca_opt_first_char(c);
367 		if (ret != NO_MCA)
368 			return (ret);
369 	}
370 	if (optgetname) {
371 		/* We're getting a long option name.  */
372 		if (c != '\n' && c != '\r')
373 			return (mca_opt_nonfirst_char(c));
374 		if (curropt == NULL) {
375 			parg.p_string = get_cmdbuf();
376 			error("There is no --%s option", &parg);
377 			return (MCA_DONE);
378 		}
379 		optgetname = FALSE;
380 		cmd_reset();
381 	} else {
382 		if (is_erase_char(c))
383 			return (NO_MCA);
384 		if (curropt != NULL)
385 			/* We're getting the option parameter. */
386 			return (NO_MCA);
387 		curropt = findopt(c);
388 		if (curropt == NULL) {
389 			parg.p_string = propt(c);
390 			error("There is no %s option", &parg);
391 			return (MCA_DONE);
392 		}
393 	}
394 	/*
395 	 * If the option which was entered does not take a
396 	 * parameter, toggle the option immediately,
397 	 * so user doesn't have to hit RETURN.
398 	 */
399 	if ((optflag & ~OPT_NO_PROMPT) != OPT_TOGGLE ||
400 	    !opt_has_param(curropt)) {
401 		toggle_option(curropt, islower(c), "", optflag);
402 		return (MCA_DONE);
403 	}
404 	/*
405 	 * Display a prompt appropriate for the option parameter.
406 	 */
407 	start_mca(A_OPT_TOGGLE, opt_prompt(curropt), NULL, 0);
408 	return (MCA_MORE);
409 }
410 
411 /*
412  * Handle a char of a search command.
413  */
414 static int
415 mca_search_char(int c)
416 {
417 	int flag = 0;
418 
419 	/*
420 	 * Certain characters as the first char of
421 	 * the pattern have special meaning:
422 	 *	!  Toggle the NO_MATCH flag
423 	 *	*  Toggle the PAST_EOF flag
424 	 *	@  Toggle the FIRST_FILE flag
425 	 */
426 	if (len_cmdbuf() > 0)
427 		return (NO_MCA);
428 
429 	switch (c) {
430 	case CONTROL('E'): /* ignore END of file */
431 	case '*':
432 		if (mca != A_FILTER)
433 			flag = SRCH_PAST_EOF;
434 		break;
435 	case CONTROL('F'): /* FIRST file */
436 	case '@':
437 		if (mca != A_FILTER)
438 			flag = SRCH_FIRST_FILE;
439 		break;
440 	case CONTROL('K'): /* KEEP position */
441 		if (mca != A_FILTER)
442 			flag = SRCH_NO_MOVE;
443 		break;
444 	case CONTROL('R'): /* Don't use REGULAR EXPRESSIONS */
445 		flag = SRCH_NO_REGEX;
446 		break;
447 	case CONTROL('N'): /* NOT match */
448 	case '!':
449 		flag = SRCH_NO_MATCH;
450 		break;
451 	}
452 
453 	if (flag != 0) {
454 		search_type ^= flag;
455 		mca_search();
456 		return (MCA_MORE);
457 	}
458 	return (NO_MCA);
459 }
460 
461 /*
462  * Handle a character of a multi-character command.
463  */
464 static int
465 mca_char(int c)
466 {
467 	int ret;
468 
469 	switch (mca) {
470 	case 0:
471 		/*
472 		 * We're not in a multicharacter command.
473 		 */
474 		return (NO_MCA);
475 
476 	case A_PREFIX:
477 		/*
478 		 * In the prefix of a command.
479 		 * This not considered a multichar command
480 		 * (even tho it uses cmdbuf, etc.).
481 		 * It is handled in the commands() switch.
482 		 */
483 		return (NO_MCA);
484 
485 	case A_DIGIT:
486 		/*
487 		 * Entering digits of a number.
488 		 * Terminated by a non-digit.
489 		 */
490 		if (!((c >= '0' && c <= '9') || c == '.') && editchar(c,
491 		    EC_PEEK|EC_NOHISTORY|EC_NOCOMPLETE|EC_NORIGHTLEFT) ==
492 		    A_INVALID) {
493 			/*
494 			 * Not part of the number.
495 			 * End the number and treat this char
496 			 * as a normal command character.
497 			 */
498 			number = cmd_int(&fraction);
499 			mca = 0;
500 			cmd_accept();
501 			return (NO_MCA);
502 		}
503 		break;
504 
505 	case A_OPT_TOGGLE:
506 		ret = mca_opt_char(c);
507 		if (ret != NO_MCA)
508 			return (ret);
509 		break;
510 
511 	case A_F_SEARCH:
512 	case A_B_SEARCH:
513 	case A_FILTER:
514 		ret = mca_search_char(c);
515 		if (ret != NO_MCA)
516 			return (ret);
517 		break;
518 
519 	default:
520 		/* Other multicharacter command. */
521 		break;
522 	}
523 
524 	/*
525 	 * The multichar command is terminated by a newline.
526 	 */
527 	if (c == '\n' || c == '\r') {
528 		/*
529 		 * Execute the command.
530 		 */
531 		exec_mca();
532 		return (MCA_DONE);
533 	}
534 
535 	/*
536 	 * Append the char to the command buffer.
537 	 */
538 	if (cmd_char(c) == CC_QUIT)
539 		/*
540 		 * Abort the multi-char command.
541 		 */
542 		return (MCA_DONE);
543 
544 	if ((mca == A_F_BRACKET || mca == A_B_BRACKET) && len_cmdbuf() >= 2) {
545 		/*
546 		 * Special case for the bracket-matching commands.
547 		 * Execute the command after getting exactly two
548 		 * characters from the user.
549 		 */
550 		exec_mca();
551 		return (MCA_DONE);
552 	}
553 
554 	/*
555 	 * Need another character.
556 	 */
557 	return (MCA_MORE);
558 }
559 
560 /*
561  * Discard any buffered file data.
562  */
563 static void
564 clear_buffers(void)
565 {
566 	if (!(ch_getflags() & CH_CANSEEK))
567 		return;
568 	ch_flush();
569 	clr_linenum();
570 	clr_hilite();
571 }
572 
573 /*
574  * Make sure the screen is displayed.
575  */
576 static void
577 make_display(void)
578 {
579 	/*
580 	 * If nothing is displayed yet, display starting from initial_scrpos.
581 	 */
582 	if (empty_screen()) {
583 		if (initial_scrpos.pos == -1)
584 			/*
585 			 * {{ Maybe this should be:
586 			 *    jump_loc(ch_zero(), jump_sline);
587 			 *    but this behavior seems rather unexpected
588 			 *    on the first screen. }}
589 			 */
590 			jump_loc(ch_zero(), 1);
591 		else
592 			jump_loc(initial_scrpos.pos, initial_scrpos.ln);
593 	} else if (screen_trashed) {
594 		int save_top_scroll = top_scroll;
595 		int save_ignore_eoi = ignore_eoi;
596 		top_scroll = 1;
597 		ignore_eoi = 0;
598 		if (screen_trashed == 2) {
599 			/*
600 			 * Special case used by ignore_eoi: re-open the input
601 			 * file and jump to the end of the file.
602 			 */
603 			reopen_curr_ifile();
604 			jump_forw();
605 		}
606 		repaint();
607 		top_scroll = save_top_scroll;
608 		ignore_eoi = save_ignore_eoi;
609 	}
610 }
611 
612 /*
613  * Display the appropriate prompt.
614  */
615 static void
616 prompt(void)
617 {
618 	const char *p;
619 
620 	if (ungot != NULL) {
621 		/*
622 		 * No prompt necessary if commands are from
623 		 * ungotten chars rather than from the user.
624 		 */
625 		return;
626 	}
627 
628 	/*
629 	 * Make sure the screen is displayed.
630 	 */
631 	make_display();
632 	bottompos = position(BOTTOM_PLUS_ONE);
633 
634 	/*
635 	 * If we've hit EOF on the last file and the -E flag is set, quit.
636 	 */
637 	if (get_quit_at_eof() == OPT_ONPLUS &&
638 	    eof_displayed() && !(ch_getflags() & CH_HELPFILE) &&
639 	    next_ifile(curr_ifile) == NULL)
640 		quit(QUIT_OK);
641 
642 	/*
643 	 * If the entire file is displayed and the -F flag is set, quit.
644 	 */
645 	if (quit_if_one_screen &&
646 	    entire_file_displayed() && !(ch_getflags() & CH_HELPFILE) &&
647 	    next_ifile(curr_ifile) == NULL)
648 		quit(QUIT_OK);
649 
650 	/*
651 	 * Select the proper prompt and display it.
652 	 */
653 	/*
654 	 * If the previous action was a forward movement,
655 	 * don't clear the bottom line of the display;
656 	 * just print the prompt since the forward movement guarantees
657 	 * that we're in the right position to display the prompt.
658 	 * Clearing the line could cause a problem: for example, if the last
659 	 * line displayed ended at the right screen edge without a newline,
660 	 * then clearing would clear the last displayed line rather than
661 	 * the prompt line.
662 	 */
663 	if (!forw_prompt)
664 		clear_bot();
665 	clear_cmd();
666 	forw_prompt = 0;
667 	p = prompt_string();
668 	if (is_filtering())
669 		putstr("& ");
670 	if (p == NULL || *p == '\0') {
671 		putchr(':');
672 	} else {
673 		at_enter(AT_STANDOUT);
674 		putstr(p);
675 		at_exit();
676 	}
677 	clear_eol();
678 }
679 
680 /*
681  * Display the less version message.
682  */
683 void
684 dispversion(void)
685 {
686 	PARG parg;
687 
688 	parg.p_string = version;
689 	error("less %s", &parg);
690 }
691 
692 /*
693  * Get command character.
694  * The character normally comes from the keyboard,
695  * but may come from ungotten characters
696  * (characters previously given to ungetcc or ungetsc).
697  */
698 int
699 getcc(void)
700 {
701 	if (unget_end) {
702 		/*
703 		 * We have just run out of ungotten chars.
704 		 */
705 		unget_end = 0;
706 		if (len_cmdbuf() == 0 || !empty_screen())
707 			return (getchr());
708 		/*
709 		 * Command is incomplete, so try to complete it.
710 		 */
711 		switch (mca) {
712 		case A_DIGIT:
713 			/*
714 			 * We have a number but no command.  Treat as #g.
715 			 */
716 			return ('g');
717 
718 		case A_F_SEARCH:
719 		case A_B_SEARCH:
720 			/*
721 			 * We have "/string" but no newline.  Add the \n.
722 			 */
723 			return ('\n');
724 
725 		default:
726 			/*
727 			 * Some other incomplete command.  Let user complete it.
728 			 */
729 			return (getchr());
730 		}
731 	}
732 
733 	if (ungot == NULL) {
734 		/*
735 		 * Normal case: no ungotten chars, so get one from the user.
736 		 */
737 		return (getchr());
738 	}
739 
740 	/*
741 	 * Return the next ungotten char.
742 	 */
743 	{
744 		struct ungot *ug = ungot;
745 		int c = ug->ug_char;
746 		ungot = ug->ug_next;
747 		free(ug);
748 		unget_end = (ungot == NULL);
749 		return (c);
750 	}
751 }
752 
753 /*
754  * "Unget" a command character.
755  * The next getcc() will return this character.
756  */
757 void
758 ungetcc(int c)
759 {
760 	struct ungot *ug = ecalloc(1, sizeof (struct ungot));
761 
762 	ug->ug_char = c;
763 	ug->ug_next = ungot;
764 	ungot = ug;
765 	unget_end = 0;
766 }
767 
768 /*
769  * Unget a whole string of command characters.
770  * The next sequence of getcc()'s will return this string.
771  */
772 void
773 ungetsc(char *s)
774 {
775 	char *p;
776 
777 	for (p = s + strlen(s) - 1; p >= s; p--)
778 		ungetcc(*p);
779 }
780 
781 /*
782  * Search for a pattern, possibly in multiple files.
783  * If SRCH_FIRST_FILE is set, begin searching at the first file.
784  * If SRCH_PAST_EOF is set, continue the search thru multiple files.
785  */
786 static void
787 multi_search(char *pattern, int n)
788 {
789 	int nomore;
790 	IFILE save_ifile;
791 	int changed_file;
792 
793 	changed_file = 0;
794 	save_ifile = save_curr_ifile();
795 
796 	if (search_type & SRCH_FIRST_FILE) {
797 		/*
798 		 * Start at the first (or last) file
799 		 * in the command line list.
800 		 */
801 		if (search_type & SRCH_FORW)
802 			nomore = edit_first();
803 		else
804 			nomore = edit_last();
805 		if (nomore) {
806 			unsave_ifile(save_ifile);
807 			return;
808 		}
809 		changed_file = 1;
810 		search_type &= ~SRCH_FIRST_FILE;
811 	}
812 
813 	for (;;) {
814 		n = search(search_type, pattern, n);
815 		/*
816 		 * The SRCH_NO_MOVE flag doesn't "stick": it gets cleared
817 		 * after being used once.  This allows "n" to work after
818 		 * using a /@@ search.
819 		 */
820 		search_type &= ~SRCH_NO_MOVE;
821 		if (n == 0) {
822 			/*
823 			 * Found it.
824 			 */
825 			unsave_ifile(save_ifile);
826 			return;
827 		}
828 
829 		if (n < 0)
830 			/*
831 			 * Some kind of error in the search.
832 			 * Error message has been printed by search().
833 			 */
834 			break;
835 
836 		if ((search_type & SRCH_PAST_EOF) == 0)
837 			/*
838 			 * We didn't find a match, but we're
839 			 * supposed to search only one file.
840 			 */
841 			break;
842 		/*
843 		 * Move on to the next file.
844 		 */
845 		if (search_type & SRCH_FORW)
846 			nomore = edit_next(1);
847 		else
848 			nomore = edit_prev(1);
849 		if (nomore)
850 			break;
851 		changed_file = 1;
852 	}
853 
854 	/*
855 	 * Didn't find it.
856 	 * Print an error message if we haven't already.
857 	 */
858 	if (n > 0)
859 		error("Pattern not found", NULL);
860 
861 	if (changed_file) {
862 		/*
863 		 * Restore the file we were originally viewing.
864 		 */
865 		reedit_ifile(save_ifile);
866 	} else {
867 		unsave_ifile(save_ifile);
868 	}
869 }
870 
871 /*
872  * Forward forever, or until a highlighted line appears.
873  */
874 static int
875 forw_loop(int until_hilite)
876 {
877 	off_t curr_len;
878 
879 	if (ch_getflags() & CH_HELPFILE)
880 		return (A_NOACTION);
881 
882 	cmd_exec();
883 	jump_forw();
884 	curr_len = ch_length();
885 	highest_hilite = until_hilite ? curr_len : -1;
886 	ignore_eoi = 1;
887 	while (!any_sigs()) {
888 		if (until_hilite && highest_hilite > curr_len) {
889 			ring_bell();
890 			break;
891 		}
892 		make_display();
893 		forward(1, 0, 0);
894 	}
895 	ignore_eoi = 0;
896 	ch_set_eof();
897 
898 	/*
899 	 * This gets us back in "F mode" after processing
900 	 * a non-abort signal (e.g. window-change).
901 	 */
902 	if (any_sigs() && !abort_sigs())
903 		return (until_hilite ? A_F_UNTIL_HILITE : A_F_FOREVER);
904 
905 	return (A_NOACTION);
906 }
907 
908 /*
909  * Main command processor.
910  * Accept and execute commands until a quit command.
911  */
912 void
913 commands(void)
914 {
915 	int c = 0;
916 	int action;
917 	char *cbuf;
918 	int newaction;
919 	int save_search_type;
920 	char *extra;
921 	char tbuf[2];
922 	PARG parg;
923 	IFILE old_ifile;
924 	IFILE new_ifile;
925 	char *tagfile;
926 
927 	search_type = SRCH_FORW;
928 	wscroll = (sc_height + 1) / 2;
929 	newaction = A_NOACTION;
930 
931 	for (;;) {
932 		mca = 0;
933 		cmd_accept();
934 		number = 0;
935 		curropt = NULL;
936 
937 		/*
938 		 * See if any signals need processing.
939 		 */
940 		if (any_sigs()) {
941 			psignals();
942 			if (quitting)
943 				quit(QUIT_SAVED_STATUS);
944 		}
945 
946 		/*
947 		 * Display prompt and accept a character.
948 		 */
949 		cmd_reset();
950 		prompt();
951 		if (any_sigs())
952 			continue;
953 		if (newaction == A_NOACTION)
954 			c = getcc();
955 
956 again:
957 		if (any_sigs())
958 			continue;
959 
960 		if (newaction != A_NOACTION) {
961 			action = newaction;
962 			newaction = A_NOACTION;
963 		} else {
964 			/*
965 			 * If we are in a multicharacter command, call mca_char.
966 			 * Otherwise we call fcmd_decode to determine the
967 			 * action to be performed.
968 			 */
969 			if (mca)
970 				switch (mca_char(c)) {
971 				case MCA_MORE:
972 					/*
973 					 * Need another character.
974 					 */
975 					c = getcc();
976 					goto again;
977 				case MCA_DONE:
978 					/*
979 					 * Command has been handled by mca_char.
980 					 * Start clean with a prompt.
981 					 */
982 					continue;
983 				case NO_MCA:
984 					/*
985 					 * Not a multi-char command
986 					 * (at least, not anymore).
987 					 */
988 					break;
989 				}
990 
991 			/*
992 			 * Decode the command character and decide what to do.
993 			 */
994 			if (mca) {
995 				/*
996 				 * We're in a multichar command.
997 				 * Add the character to the command buffer
998 				 * and display it on the screen.
999 				 * If the user backspaces past the start
1000 				 * of the line, abort the command.
1001 				 */
1002 				if (cmd_char(c) == CC_QUIT || len_cmdbuf() == 0)
1003 					continue;
1004 				cbuf = get_cmdbuf();
1005 			} else {
1006 				/*
1007 				 * Don't use cmd_char if we're starting fresh
1008 				 * at the beginning of a command, because we
1009 				 * don't want to echo the command until we know
1010 				 * it is a multichar command.  We also don't
1011 				 * want erase_char/kill_char to be treated
1012 				 * as line editing characters.
1013 				 */
1014 				tbuf[0] = (char)c;
1015 				tbuf[1] = '\0';
1016 				cbuf = tbuf;
1017 			}
1018 			extra = NULL;
1019 			action = fcmd_decode(cbuf, &extra);
1020 			/*
1021 			 * If an "extra" string was returned,
1022 			 * process it as a string of command characters.
1023 			 */
1024 			if (extra != NULL)
1025 				ungetsc(extra);
1026 		}
1027 		/*
1028 		 * Clear the cmdbuf string.
1029 		 * (But not if we're in the prefix of a command,
1030 		 * because the partial command string is kept there.)
1031 		 */
1032 		if (action != A_PREFIX)
1033 			cmd_reset();
1034 
1035 		switch (action) {
1036 		case A_DIGIT:
1037 			/*
1038 			 * First digit of a number.
1039 			 */
1040 			start_mca(A_DIGIT, ":", (void*)NULL, CF_QUIT_ON_ERASE);
1041 			goto again;
1042 
1043 		case A_F_WINDOW:
1044 			/*
1045 			 * Forward one window (and set the window size).
1046 			 */
1047 			if (number > 0)
1048 				swindow = (int)number;
1049 			/* FALLTHRU */
1050 		case A_F_SCREEN:
1051 			/*
1052 			 * Forward one screen.
1053 			 */
1054 			if (number <= 0)
1055 				number = get_swindow();
1056 			cmd_exec();
1057 			if (show_attn)
1058 				set_attnpos(bottompos);
1059 			forward((int)number, 0, 1);
1060 			break;
1061 
1062 		case A_B_WINDOW:
1063 			/*
1064 			 * Backward one window (and set the window size).
1065 			 */
1066 			if (number > 0)
1067 				swindow = (int)number;
1068 			/* FALLTHRU */
1069 		case A_B_SCREEN:
1070 			/*
1071 			 * Backward one screen.
1072 			 */
1073 			if (number <= 0)
1074 				number = get_swindow();
1075 			cmd_exec();
1076 			backward((int)number, 0, 1);
1077 			break;
1078 
1079 		case A_F_LINE:
1080 			/*
1081 			 * Forward N (default 1) line.
1082 			 */
1083 			if (number <= 0)
1084 				number = 1;
1085 			cmd_exec();
1086 			if (show_attn == OPT_ONPLUS && number > 1)
1087 				set_attnpos(bottompos);
1088 			forward((int)number, 0, 0);
1089 			break;
1090 
1091 		case A_B_LINE:
1092 			/*
1093 			 * Backward N (default 1) line.
1094 			 */
1095 			if (number <= 0)
1096 				number = 1;
1097 			cmd_exec();
1098 			backward((int)number, 0, 0);
1099 			break;
1100 
1101 		case A_F_SKIP:
1102 			/*
1103 			 * Skip ahead one screen, and then number lines.
1104 			 */
1105 			if (number <= 0) {
1106 				number = get_swindow();
1107 			} else {
1108 				number += get_swindow();
1109 			}
1110 			cmd_exec();
1111 			if (show_attn == OPT_ONPLUS)
1112 				set_attnpos(bottompos);
1113 			forward((int)number, 0, 1);
1114 			break;
1115 
1116 		case A_FF_LINE:
1117 			/*
1118 			 * Force forward N (default 1) line.
1119 			 */
1120 			if (number <= 0)
1121 				number = 1;
1122 			cmd_exec();
1123 			if (show_attn == OPT_ONPLUS && number > 1)
1124 				set_attnpos(bottompos);
1125 			forward((int)number, 1, 0);
1126 			break;
1127 
1128 		case A_BF_LINE:
1129 			/*
1130 			 * Force backward N (default 1) line.
1131 			 */
1132 			if (number <= 0)
1133 				number = 1;
1134 			cmd_exec();
1135 			backward((int)number, 1, 0);
1136 			break;
1137 
1138 		case A_FF_SCREEN:
1139 			/*
1140 			 * Force forward one screen.
1141 			 */
1142 			if (number <= 0)
1143 				number = get_swindow();
1144 			cmd_exec();
1145 			if (show_attn == OPT_ONPLUS)
1146 				set_attnpos(bottompos);
1147 			forward((int)number, 1, 0);
1148 			break;
1149 
1150 		case A_F_FOREVER:
1151 			/*
1152 			 * Forward forever, ignoring EOF.
1153 			 */
1154 			newaction = forw_loop(0);
1155 			break;
1156 
1157 		case A_F_UNTIL_HILITE:
1158 			newaction = forw_loop(1);
1159 			break;
1160 
1161 		case A_F_SCROLL:
1162 			/*
1163 			 * Forward N lines
1164 			 * (default same as last 'd' or 'u' command).
1165 			 */
1166 			if (number > 0)
1167 				wscroll = (int)number;
1168 			cmd_exec();
1169 			if (show_attn == OPT_ONPLUS)
1170 				set_attnpos(bottompos);
1171 			forward(wscroll, 0, 0);
1172 			break;
1173 
1174 		case A_B_SCROLL:
1175 			/*
1176 			 * Forward N lines
1177 			 * (default same as last 'd' or 'u' command).
1178 			 */
1179 			if (number > 0)
1180 				wscroll = (int)number;
1181 			cmd_exec();
1182 			backward(wscroll, 0, 0);
1183 			break;
1184 
1185 		case A_FREPAINT:
1186 			/*
1187 			 * Flush buffers, then repaint screen.
1188 			 * Don't flush the buffers on a pipe!
1189 			 */
1190 			clear_buffers();
1191 			/* FALLTHRU */
1192 		case A_REPAINT:
1193 			/*
1194 			 * Repaint screen.
1195 			 */
1196 			cmd_exec();
1197 			repaint();
1198 			break;
1199 
1200 		case A_GOLINE:
1201 			/*
1202 			 * Go to line N, default beginning of file.
1203 			 */
1204 			if (number <= 0)
1205 				number = 1;
1206 			cmd_exec();
1207 			jump_back(number);
1208 			break;
1209 
1210 		case A_PERCENT:
1211 			/*
1212 			 * Go to a specified percentage into the file.
1213 			 */
1214 			if (number < 0) {
1215 				number = 0;
1216 				fraction = 0;
1217 			}
1218 			if (number > 100) {
1219 				number = 100;
1220 				fraction = 0;
1221 			}
1222 			cmd_exec();
1223 			jump_percent((int)number, fraction);
1224 			break;
1225 
1226 		case A_GOEND:
1227 			/*
1228 			 * Go to line N, default end of file.
1229 			 */
1230 			cmd_exec();
1231 			if (number <= 0)
1232 				jump_forw();
1233 			else
1234 				jump_back(number);
1235 			break;
1236 
1237 		case A_GOPOS:
1238 			/*
1239 			 * Go to a specified byte position in the file.
1240 			 */
1241 			cmd_exec();
1242 			if (number < 0)
1243 				number = 0;
1244 			jump_line_loc((off_t) number, jump_sline);
1245 			break;
1246 
1247 		case A_STAT:
1248 			/*
1249 			 * Print file name, etc.
1250 			 */
1251 			if (ch_getflags() & CH_HELPFILE)
1252 				break;
1253 			cmd_exec();
1254 			parg.p_string = eq_message();
1255 			error("%s", &parg);
1256 			break;
1257 
1258 		case A_VERSION:
1259 			/*
1260 			 * Print version number, without the "@(#)".
1261 			 */
1262 			cmd_exec();
1263 			dispversion();
1264 			break;
1265 
1266 		case A_QUIT:
1267 			/*
1268 			 * Exit.
1269 			 */
1270 			if (curr_ifile != NULL &&
1271 			    ch_getflags() & CH_HELPFILE) {
1272 				/*
1273 				 * Quit while viewing the help file
1274 				 * just means return to viewing the
1275 				 * previous file.
1276 				 */
1277 				hshift = save_hshift;
1278 				if (edit_prev(1) == 0)
1279 					break;
1280 			}
1281 			if (extra != NULL)
1282 				quit(*extra);
1283 			quit(QUIT_OK);
1284 			break;
1285 
1286 /*
1287  * Define abbreviation for a commonly used sequence below.
1288  */
1289 #define	DO_SEARCH() \
1290 			if (number <= 0) number = 1;	\
1291 			mca_search();			\
1292 			cmd_exec();			\
1293 			multi_search(NULL, (int)number);
1294 
1295 
1296 		case A_F_SEARCH:
1297 			/*
1298 			 * Search forward for a pattern.
1299 			 * Get the first char of the pattern.
1300 			 */
1301 			search_type = SRCH_FORW;
1302 			if (number <= 0)
1303 				number = 1;
1304 			mca_search();
1305 			c = getcc();
1306 			goto again;
1307 
1308 		case A_B_SEARCH:
1309 			/*
1310 			 * Search backward for a pattern.
1311 			 * Get the first char of the pattern.
1312 			 */
1313 			search_type = SRCH_BACK;
1314 			if (number <= 0)
1315 				number = 1;
1316 			mca_search();
1317 			c = getcc();
1318 			goto again;
1319 
1320 		case A_FILTER:
1321 			search_type = SRCH_FORW | SRCH_FILTER;
1322 			mca_search();
1323 			c = getcc();
1324 			goto again;
1325 
1326 		case A_AGAIN_SEARCH:
1327 			/*
1328 			 * Repeat previous search.
1329 			 */
1330 			DO_SEARCH();
1331 			break;
1332 
1333 		case A_T_AGAIN_SEARCH:
1334 			/*
1335 			 * Repeat previous search, multiple files.
1336 			 */
1337 			search_type |= SRCH_PAST_EOF;
1338 			DO_SEARCH();
1339 			break;
1340 
1341 		case A_REVERSE_SEARCH:
1342 			/*
1343 			 * Repeat previous search, in reverse direction.
1344 			 */
1345 			save_search_type = search_type;
1346 			search_type = SRCH_REVERSE(search_type);
1347 			DO_SEARCH();
1348 			search_type = save_search_type;
1349 			break;
1350 
1351 		case A_T_REVERSE_SEARCH:
1352 			/*
1353 			 * Repeat previous search,
1354 			 * multiple files in reverse direction.
1355 			 */
1356 			save_search_type = search_type;
1357 			search_type = SRCH_REVERSE(search_type);
1358 			search_type |= SRCH_PAST_EOF;
1359 			DO_SEARCH();
1360 			search_type = save_search_type;
1361 			break;
1362 
1363 		case A_UNDO_SEARCH:
1364 			undo_search();
1365 			break;
1366 
1367 		case A_HELP:
1368 			/*
1369 			 * Help.
1370 			 */
1371 			if (ch_getflags() & CH_HELPFILE)
1372 				break;
1373 			if (ungot != NULL || unget_end) {
1374 				error(less_is_more
1375 				    ? "Invalid option -p h"
1376 				    : "Invalid option ++h",
1377 				    NULL);
1378 				break;
1379 			}
1380 			cmd_exec();
1381 			save_hshift = hshift;
1382 			hshift = 0;
1383 			(void) edit(helpfile());
1384 			break;
1385 
1386 		case A_EXAMINE:
1387 			/*
1388 			 * Edit a new file.  Get the filename.
1389 			 */
1390 			if (secure) {
1391 				error("Command not available", NULL);
1392 				break;
1393 			}
1394 			start_mca(A_EXAMINE, "Examine: ", ml_examine, 0);
1395 			c = getcc();
1396 			goto again;
1397 
1398 		case A_VISUAL:
1399 			/*
1400 			 * Invoke an editor on the input file.
1401 			 */
1402 			if (secure) {
1403 				error("Command not available", NULL);
1404 				break;
1405 			}
1406 			if (ch_getflags() & CH_HELPFILE)
1407 				break;
1408 			if (strcmp(get_filename(curr_ifile), "-") == 0) {
1409 				error("Cannot edit standard input", NULL);
1410 				break;
1411 			}
1412 			if (curr_altfilename != NULL) {
1413 				error("WARNING: This file was viewed via "
1414 				    "LESSOPEN", NULL);
1415 			}
1416 			/*
1417 			 * Expand the editor prototype string
1418 			 * and pass it to the system to execute.
1419 			 * (Make sure the screen is displayed so the
1420 			 * expansion of "+%lm" works.)
1421 			 */
1422 			make_display();
1423 			cmd_exec();
1424 			lsystem(pr_expand(editproto, 0), NULL);
1425 			break;
1426 
1427 		case A_NEXT_FILE:
1428 			/*
1429 			 * Examine next file.
1430 			 */
1431 			if (ntags()) {
1432 				error("No next file", NULL);
1433 				break;
1434 			}
1435 			if (number <= 0)
1436 				number = 1;
1437 			if (edit_next((int)number)) {
1438 				if (get_quit_at_eof() && eof_displayed() &&
1439 				    !(ch_getflags() & CH_HELPFILE))
1440 					quit(QUIT_OK);
1441 				parg.p_string = (number > 1) ? "(N-th) " : "";
1442 				error("No %snext file", &parg);
1443 			}
1444 			break;
1445 
1446 		case A_PREV_FILE:
1447 			/*
1448 			 * Examine previous file.
1449 			 */
1450 			if (ntags()) {
1451 				error("No previous file", NULL);
1452 				break;
1453 			}
1454 			if (number <= 0)
1455 				number = 1;
1456 			if (edit_prev((int)number)) {
1457 				parg.p_string = (number > 1) ? "(N-th) " : "";
1458 				error("No %sprevious file", &parg);
1459 			}
1460 			break;
1461 
1462 		case A_NEXT_TAG:
1463 			if (number <= 0)
1464 				number = 1;
1465 			cmd_exec();
1466 			tagfile = nexttag((int)number);
1467 			if (tagfile == NULL) {
1468 				error("No next tag", NULL);
1469 				break;
1470 			}
1471 			if (edit(tagfile) == 0) {
1472 				off_t pos = tagsearch();
1473 				if (pos != -1)
1474 					jump_loc(pos, jump_sline);
1475 			}
1476 			break;
1477 
1478 		case A_PREV_TAG:
1479 			if (number <= 0)
1480 				number = 1;
1481 			tagfile = prevtag((int)number);
1482 			if (tagfile == NULL) {
1483 				error("No previous tag", NULL);
1484 				break;
1485 			}
1486 			if (edit(tagfile) == 0) {
1487 				off_t pos = tagsearch();
1488 				if (pos != -1)
1489 					jump_loc(pos, jump_sline);
1490 			}
1491 			break;
1492 
1493 		case A_INDEX_FILE:
1494 			/*
1495 			 * Examine a particular file.
1496 			 */
1497 			if (number <= 0)
1498 				number = 1;
1499 			if (edit_index((int)number))
1500 				error("No such file", NULL);
1501 			break;
1502 
1503 		case A_REMOVE_FILE:
1504 			if (ch_getflags() & CH_HELPFILE)
1505 				break;
1506 			old_ifile = curr_ifile;
1507 			new_ifile = getoff_ifile(curr_ifile);
1508 			if (new_ifile == NULL) {
1509 				ring_bell();
1510 				break;
1511 			}
1512 			if (edit_ifile(new_ifile) != 0) {
1513 				reedit_ifile(old_ifile);
1514 				break;
1515 			}
1516 			del_ifile(old_ifile);
1517 			break;
1518 
1519 		case A_OPT_TOGGLE:
1520 			optflag = OPT_TOGGLE;
1521 			optgetname = FALSE;
1522 			mca_opt_toggle();
1523 			c = getcc();
1524 			goto again;
1525 
1526 		case A_DISP_OPTION:
1527 			/*
1528 			 * Report a flag setting.
1529 			 */
1530 			optflag = OPT_NO_TOGGLE;
1531 			optgetname = FALSE;
1532 			mca_opt_toggle();
1533 			c = getcc();
1534 			goto again;
1535 
1536 		case A_FIRSTCMD:
1537 			/*
1538 			 * Set an initial command for new files.
1539 			 */
1540 			start_mca(A_FIRSTCMD, "+", NULL, 0);
1541 			c = getcc();
1542 			goto again;
1543 
1544 		case A_SETMARK:
1545 			/*
1546 			 * Set a mark.
1547 			 */
1548 			if (ch_getflags() & CH_HELPFILE)
1549 				break;
1550 			start_mca(A_SETMARK, "mark: ", (void*)NULL, 0);
1551 			c = getcc();
1552 			if (c == erase_char || c == erase2_char ||
1553 			    c == kill_char || c == '\n' || c == '\r')
1554 				break;
1555 			setmark(c);
1556 			break;
1557 
1558 		case A_GOMARK:
1559 			/*
1560 			 * Go to a mark.
1561 			 */
1562 			start_mca(A_GOMARK, "goto mark: ", (void*)NULL, 0);
1563 			c = getcc();
1564 			if (c == erase_char || c == erase2_char ||
1565 			    c == kill_char || c == '\n' || c == '\r')
1566 				break;
1567 			cmd_exec();
1568 			gomark(c);
1569 			break;
1570 
1571 		case A_PIPE:
1572 			if (secure) {
1573 				error("Command not available", NULL);
1574 				break;
1575 			}
1576 			start_mca(A_PIPE, "|mark: ", (void*)NULL, 0);
1577 			c = getcc();
1578 			if (c == erase_char || c == erase2_char ||
1579 			    c == kill_char)
1580 				break;
1581 			if (c == '\n' || c == '\r')
1582 				c = '.';
1583 			if (badmark(c))
1584 				break;
1585 			pipec = c;
1586 			start_mca(A_PIPE, "!", ml_shell, 0);
1587 			c = getcc();
1588 			goto again;
1589 
1590 		case A_B_BRACKET:
1591 		case A_F_BRACKET:
1592 			start_mca(action, "Brackets: ", (void*)NULL, 0);
1593 			c = getcc();
1594 			goto again;
1595 
1596 		case A_LSHIFT:
1597 			if (number > 0)
1598 				shift_count = number;
1599 			else
1600 				number = (shift_count > 0) ?
1601 				    shift_count : sc_width / 2;
1602 			if (number > hshift)
1603 				number = hshift;
1604 			hshift -= number;
1605 			screen_trashed = 1;
1606 			break;
1607 
1608 		case A_RSHIFT:
1609 			if (number > 0)
1610 				shift_count = number;
1611 			else
1612 				number = (shift_count > 0) ?
1613 				    shift_count : sc_width / 2;
1614 			hshift += number;
1615 			screen_trashed = 1;
1616 			break;
1617 
1618 		case A_PREFIX:
1619 			/*
1620 			 * The command is incomplete (more chars are needed).
1621 			 * Display the current char, so the user knows
1622 			 * what's going on, and get another character.
1623 			 */
1624 			if (mca != A_PREFIX) {
1625 				cmd_reset();
1626 				start_mca(A_PREFIX, " ", (void*)NULL,
1627 				    CF_QUIT_ON_ERASE);
1628 				(void) cmd_char(c);
1629 			}
1630 			c = getcc();
1631 			goto again;
1632 
1633 		case A_NOACTION:
1634 			break;
1635 
1636 		default:
1637 			ring_bell();
1638 			break;
1639 		}
1640 	}
1641 }
1642