xref: /freebsd/contrib/less/cmdbuf.c (revision d5fc25e5d6c52b306312784663ccad85923a9c76)
1 /*
2  * Copyright (C) 1984-2008  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 #if CMD_HISTORY
666 	curr_mlist = (struct mlist *) mlist;
667 	curr_cmdflags = cmdflags;
668 
669 	/* Make sure the next up-arrow moves to the last string in the mlist. */
670 	if (curr_mlist != NULL)
671 		curr_mlist->curr_mp = curr_mlist;
672 #endif
673 }
674 
675 #if CMD_HISTORY
676 /*
677  * Move up or down in the currently selected command history list.
678  */
679 	static int
680 cmd_updown(action)
681 	int action;
682 {
683 	char *s;
684 
685 	if (curr_mlist == NULL)
686 	{
687 		/*
688 		 * The current command has no history list.
689 		 */
690 		bell();
691 		return (CC_OK);
692 	}
693 	cmd_home();
694 	clear_eol();
695 	/*
696 	 * Move curr_mp to the next/prev entry.
697 	 */
698 	if (action == EC_UP)
699 		curr_mlist->curr_mp = curr_mlist->curr_mp->prev;
700 	else
701 		curr_mlist->curr_mp = curr_mlist->curr_mp->next;
702 	/*
703 	 * Copy the entry into cmdbuf and echo it on the screen.
704 	 */
705 	s = curr_mlist->curr_mp->string;
706 	if (s == NULL)
707 		s = "";
708 	strcpy(cmdbuf, s);
709 	for (cp = cmdbuf;  *cp != '\0';  )
710 		cmd_right();
711 	return (CC_OK);
712 }
713 #endif
714 
715 /*
716  * Add a string to a history list.
717  */
718 	public void
719 cmd_addhist(mlist, cmd)
720 	struct mlist *mlist;
721 	char *cmd;
722 {
723 #if CMD_HISTORY
724 	struct mlist *ml;
725 
726 	/*
727 	 * Don't save a trivial command.
728 	 */
729 	if (strlen(cmd) == 0)
730 		return;
731 
732 	/*
733 	 * Save the command unless it's a duplicate of the
734 	 * last command in the history.
735 	 */
736 	ml = mlist->prev;
737 	if (ml == mlist || strcmp(ml->string, cmd) != 0)
738 	{
739 		/*
740 		 * Did not find command in history.
741 		 * Save the command and put it at the end of the history list.
742 		 */
743 		ml = (struct mlist *) ecalloc(1, sizeof(struct mlist));
744 		ml->string = save(cmd);
745 		ml->next = mlist;
746 		ml->prev = mlist->prev;
747 		mlist->prev->next = ml;
748 		mlist->prev = ml;
749 	}
750 	/*
751 	 * Point to the cmd just after the just-accepted command.
752 	 * Thus, an UPARROW will always retrieve the previous command.
753 	 */
754 	mlist->curr_mp = ml->next;
755 #endif
756 }
757 
758 /*
759  * Accept the command in the command buffer.
760  * Add it to the currently selected history list.
761  */
762 	public void
763 cmd_accept()
764 {
765 #if CMD_HISTORY
766 	/*
767 	 * Nothing to do if there is no currently selected history list.
768 	 */
769 	if (curr_mlist == NULL)
770 		return;
771 	cmd_addhist(curr_mlist, cmdbuf);
772 	curr_mlist->modified = 1;
773 #endif
774 }
775 
776 /*
777  * Try to perform a line-edit function on the command buffer,
778  * using a specified char as a line-editing command.
779  * Returns:
780  *	CC_PASS	The char does not invoke a line edit function.
781  *	CC_OK	Line edit function done.
782  *	CC_QUIT	The char requests the current command to be aborted.
783  */
784 	static int
785 cmd_edit(c)
786 	int c;
787 {
788 	int action;
789 	int flags;
790 
791 #if TAB_COMPLETE_FILENAME
792 #define	not_in_completion()	in_completion = 0
793 #else
794 #define	not_in_completion()
795 #endif
796 
797 	/*
798 	 * See if the char is indeed a line-editing command.
799 	 */
800 	flags = 0;
801 #if CMD_HISTORY
802 	if (curr_mlist == NULL)
803 		/*
804 		 * No current history; don't accept history manipulation cmds.
805 		 */
806 		flags |= EC_NOHISTORY;
807 #endif
808 #if TAB_COMPLETE_FILENAME
809 	if (curr_mlist == ml_search)
810 		/*
811 		 * In a search command; don't accept file-completion cmds.
812 		 */
813 		flags |= EC_NOCOMPLETE;
814 #endif
815 
816 	action = editchar(c, flags);
817 
818 	switch (action)
819 	{
820 	case EC_RIGHT:
821 		not_in_completion();
822 		return (cmd_right());
823 	case EC_LEFT:
824 		not_in_completion();
825 		return (cmd_left());
826 	case EC_W_RIGHT:
827 		not_in_completion();
828 		while (*cp != '\0' && *cp != ' ')
829 			cmd_right();
830 		while (*cp == ' ')
831 			cmd_right();
832 		return (CC_OK);
833 	case EC_W_LEFT:
834 		not_in_completion();
835 		while (cp > cmdbuf && cp[-1] == ' ')
836 			cmd_left();
837 		while (cp > cmdbuf && cp[-1] != ' ')
838 			cmd_left();
839 		return (CC_OK);
840 	case EC_HOME:
841 		not_in_completion();
842 		cmd_offset = 0;
843 		cmd_home();
844 		cmd_repaint(cp);
845 		return (CC_OK);
846 	case EC_END:
847 		not_in_completion();
848 		while (*cp != '\0')
849 			cmd_right();
850 		return (CC_OK);
851 	case EC_INSERT:
852 		not_in_completion();
853 		return (CC_OK);
854 	case EC_BACKSPACE:
855 		not_in_completion();
856 		return (cmd_erase());
857 	case EC_LINEKILL:
858 		not_in_completion();
859 		return (cmd_kill());
860 	case EC_W_BACKSPACE:
861 		not_in_completion();
862 		return (cmd_werase());
863 	case EC_DELETE:
864 		not_in_completion();
865 		return (cmd_delete());
866 	case EC_W_DELETE:
867 		not_in_completion();
868 		return (cmd_wdelete());
869 	case EC_LITERAL:
870 		literal = 1;
871 		return (CC_OK);
872 #if CMD_HISTORY
873 	case EC_UP:
874 	case EC_DOWN:
875 		not_in_completion();
876 		return (cmd_updown(action));
877 #endif
878 #if TAB_COMPLETE_FILENAME
879 	case EC_F_COMPLETE:
880 	case EC_B_COMPLETE:
881 	case EC_EXPAND:
882 		return (cmd_complete(action));
883 #endif
884 	case EC_NOACTION:
885 		return (CC_OK);
886 	default:
887 		not_in_completion();
888 		return (CC_PASS);
889 	}
890 }
891 
892 #if TAB_COMPLETE_FILENAME
893 /*
894  * Insert a string into the command buffer, at the current position.
895  */
896 	static int
897 cmd_istr(str)
898 	char *str;
899 {
900 	char *s;
901 	int action;
902 	char *endline = str + strlen(str);
903 
904 	for (s = str;  *s != '\0';  )
905 	{
906 		char *os = s;
907 		step_char(&s, +1, endline);
908 		action = cmd_ichar(os, s - os);
909 		if (action != CC_OK)
910 		{
911 			bell();
912 			return (action);
913 		}
914 	}
915 	return (CC_OK);
916 }
917 
918 /*
919  * Find the beginning and end of the "current" word.
920  * This is the word which the cursor (cp) is inside or at the end of.
921  * Return pointer to the beginning of the word and put the
922  * cursor at the end of the word.
923  */
924 	static char *
925 delimit_word()
926 {
927 	char *word;
928 #if SPACES_IN_FILENAMES
929 	char *p;
930 	int delim_quoted = 0;
931 	int meta_quoted = 0;
932 	char *esc = get_meta_escape();
933 	int esclen = strlen(esc);
934 #endif
935 
936 	/*
937 	 * Move cursor to end of word.
938 	 */
939 	if (*cp != ' ' && *cp != '\0')
940 	{
941 		/*
942 		 * Cursor is on a nonspace.
943 		 * Move cursor right to the next space.
944 		 */
945 		while (*cp != ' ' && *cp != '\0')
946 			cmd_right();
947 	} else if (cp > cmdbuf && cp[-1] != ' ')
948 	{
949 		/*
950 		 * Cursor is on a space, and char to the left is a nonspace.
951 		 * We're already at the end of the word.
952 		 */
953 		;
954 #if 0
955 	} else
956 	{
957 		/*
958 		 * Cursor is on a space and char to the left is a space.
959 		 * Huh? There's no word here.
960 		 */
961 		return (NULL);
962 #endif
963 	}
964 	/*
965 	 * Find the beginning of the word which the cursor is in.
966 	 */
967 	if (cp == cmdbuf)
968 		return (NULL);
969 #if SPACES_IN_FILENAMES
970 	/*
971 	 * If we have an unbalanced quote (that is, an open quote
972 	 * without a corresponding close quote), we return everything
973 	 * from the open quote, including spaces.
974 	 */
975 	for (word = cmdbuf;  word < cp;  word++)
976 		if (*word != ' ')
977 			break;
978 	if (word >= cp)
979 		return (cp);
980 	for (p = cmdbuf;  p < cp;  p++)
981 	{
982 		if (meta_quoted)
983 		{
984 			meta_quoted = 0;
985 		} else if (esclen > 0 && p + esclen < cp &&
986 		           strncmp(p, esc, esclen) == 0)
987 		{
988 			meta_quoted = 1;
989 			p += esclen - 1;
990 		} else if (delim_quoted)
991 		{
992 			if (*p == closequote)
993 				delim_quoted = 0;
994 		} else /* (!delim_quoted) */
995 		{
996 			if (*p == openquote)
997 				delim_quoted = 1;
998 			else if (*p == ' ')
999 				word = p+1;
1000 		}
1001 	}
1002 #endif
1003 	return (word);
1004 }
1005 
1006 /*
1007  * Set things up to enter completion mode.
1008  * Expand the word under the cursor into a list of filenames
1009  * which start with that word, and set tk_text to that list.
1010  */
1011 	static void
1012 init_compl()
1013 {
1014 	char *word;
1015 	char c;
1016 
1017 	/*
1018 	 * Get rid of any previous tk_text.
1019 	 */
1020 	if (tk_text != NULL)
1021 	{
1022 		free(tk_text);
1023 		tk_text = NULL;
1024 	}
1025 	/*
1026 	 * Find the original (uncompleted) word in the command buffer.
1027 	 */
1028 	word = delimit_word();
1029 	if (word == NULL)
1030 		return;
1031 	/*
1032 	 * Set the insertion point to the point in the command buffer
1033 	 * where the original (uncompleted) word now sits.
1034 	 */
1035 	tk_ipoint = word;
1036 	/*
1037 	 * Save the original (uncompleted) word
1038 	 */
1039 	if (tk_original != NULL)
1040 		free(tk_original);
1041 	tk_original = (char *) ecalloc(cp-word+1, sizeof(char));
1042 	strncpy(tk_original, word, cp-word);
1043 	/*
1044 	 * Get the expanded filename.
1045 	 * This may result in a single filename, or
1046 	 * a blank-separated list of filenames.
1047 	 */
1048 	c = *cp;
1049 	*cp = '\0';
1050 	if (*word != openquote)
1051 	{
1052 		tk_text = fcomplete(word);
1053 	} else
1054 	{
1055 		char *qword = shell_quote(word+1);
1056 		if (qword == NULL)
1057 			tk_text = fcomplete(word+1);
1058 		else
1059 		{
1060 			tk_text = fcomplete(qword);
1061 			free(qword);
1062 		}
1063 	}
1064 	*cp = c;
1065 }
1066 
1067 /*
1068  * Return the next word in the current completion list.
1069  */
1070 	static char *
1071 next_compl(action, prev)
1072 	int action;
1073 	char *prev;
1074 {
1075 	switch (action)
1076 	{
1077 	case EC_F_COMPLETE:
1078 		return (forw_textlist(&tk_tlist, prev));
1079 	case EC_B_COMPLETE:
1080 		return (back_textlist(&tk_tlist, prev));
1081 	}
1082 	/* Cannot happen */
1083 	return ("?");
1084 }
1085 
1086 /*
1087  * Complete the filename before (or under) the cursor.
1088  * cmd_complete may be called multiple times.  The global in_completion
1089  * remembers whether this call is the first time (create the list),
1090  * or a subsequent time (step thru the list).
1091  */
1092 	static int
1093 cmd_complete(action)
1094 	int action;
1095 {
1096 	char *s;
1097 
1098 	if (!in_completion || action == EC_EXPAND)
1099 	{
1100 		/*
1101 		 * Expand the word under the cursor and
1102 		 * use the first word in the expansion
1103 		 * (or the entire expansion if we're doing EC_EXPAND).
1104 		 */
1105 		init_compl();
1106 		if (tk_text == NULL)
1107 		{
1108 			bell();
1109 			return (CC_OK);
1110 		}
1111 		if (action == EC_EXPAND)
1112 		{
1113 			/*
1114 			 * Use the whole list.
1115 			 */
1116 			tk_trial = tk_text;
1117 		} else
1118 		{
1119 			/*
1120 			 * Use the first filename in the list.
1121 			 */
1122 			in_completion = 1;
1123 			init_textlist(&tk_tlist, tk_text);
1124 			tk_trial = next_compl(action, (char*)NULL);
1125 		}
1126 	} else
1127 	{
1128 		/*
1129 		 * We already have a completion list.
1130 		 * Use the next/previous filename from the list.
1131 		 */
1132 		tk_trial = next_compl(action, tk_trial);
1133 	}
1134 
1135   	/*
1136   	 * Remove the original word, or the previous trial completion.
1137   	 */
1138 	while (cp > tk_ipoint)
1139 		(void) cmd_erase();
1140 
1141 	if (tk_trial == NULL)
1142 	{
1143 		/*
1144 		 * There are no more trial completions.
1145 		 * Insert the original (uncompleted) filename.
1146 		 */
1147 		in_completion = 0;
1148 		if (cmd_istr(tk_original) != CC_OK)
1149 			goto fail;
1150 	} else
1151 	{
1152 		/*
1153 		 * Insert trial completion.
1154 		 */
1155 		if (cmd_istr(tk_trial) != CC_OK)
1156 			goto fail;
1157 		/*
1158 		 * If it is a directory, append a slash.
1159 		 */
1160 		if (is_dir(tk_trial))
1161 		{
1162 			if (cp > cmdbuf && cp[-1] == closequote)
1163 				(void) cmd_erase();
1164 			s = lgetenv("LESSSEPARATOR");
1165 			if (s == NULL)
1166 				s = PATHNAME_SEP;
1167 			if (cmd_istr(s) != CC_OK)
1168 				goto fail;
1169 		}
1170 	}
1171 
1172 	return (CC_OK);
1173 
1174 fail:
1175 	in_completion = 0;
1176 	bell();
1177 	return (CC_OK);
1178 }
1179 
1180 #endif /* TAB_COMPLETE_FILENAME */
1181 
1182 /*
1183  * Process a single character of a multi-character command, such as
1184  * a number, or the pattern of a search command.
1185  * Returns:
1186  *	CC_OK		The char was accepted.
1187  *	CC_QUIT		The char requests the command to be aborted.
1188  *	CC_ERROR	The char could not be accepted due to an error.
1189  */
1190 	public int
1191 cmd_char(c)
1192 	int c;
1193 {
1194 	int action;
1195 	int len;
1196 
1197 	if (!utf_mode)
1198 	{
1199 		cmd_mbc_buf[0] = c;
1200 		len = 1;
1201 	} else
1202 	{
1203 		/* Perform strict validation in all possible cases.  */
1204 		if (cmd_mbc_buf_len == 0)
1205 		{
1206 		 retry:
1207 			cmd_mbc_buf_index = 1;
1208 			*cmd_mbc_buf = c;
1209 			if (IS_ASCII_OCTET(c))
1210 				cmd_mbc_buf_len = 1;
1211 			else if (IS_UTF8_LEAD(c))
1212 			{
1213 				cmd_mbc_buf_len = utf_len(c);
1214 				return (CC_OK);
1215 			} else
1216 			{
1217 				/* UTF8_INVALID or stray UTF8_TRAIL */
1218 				bell();
1219 				return (CC_ERROR);
1220 			}
1221 		} else if (IS_UTF8_TRAIL(c))
1222 		{
1223 			cmd_mbc_buf[cmd_mbc_buf_index++] = c;
1224 			if (cmd_mbc_buf_index < cmd_mbc_buf_len)
1225 				return (CC_OK);
1226 			if (!is_utf8_well_formed(cmd_mbc_buf))
1227 			{
1228 				/* complete, but not well formed (non-shortest form), sequence */
1229 				cmd_mbc_buf_len = 0;
1230 				bell();
1231 				return (CC_ERROR);
1232 			}
1233 		} else
1234 		{
1235 			/* Flush incomplete (truncated) sequence.  */
1236 			cmd_mbc_buf_len = 0;
1237 			bell();
1238 			/* Handle new char.  */
1239 			goto retry;
1240 		}
1241 
1242 		len = cmd_mbc_buf_len;
1243 		cmd_mbc_buf_len = 0;
1244 	}
1245 
1246 	if (literal)
1247 	{
1248 		/*
1249 		 * Insert the char, even if it is a line-editing char.
1250 		 */
1251 		literal = 0;
1252 		return (cmd_ichar(cmd_mbc_buf, len));
1253 	}
1254 
1255 	/*
1256 	 * See if it is a line-editing character.
1257 	 */
1258 	if (in_mca() && len == 1)
1259 	{
1260 		action = cmd_edit(c);
1261 		switch (action)
1262 		{
1263 		case CC_OK:
1264 		case CC_QUIT:
1265 			return (action);
1266 		case CC_PASS:
1267 			break;
1268 		}
1269 	}
1270 
1271 	/*
1272 	 * Insert the char into the command buffer.
1273 	 */
1274 	return (cmd_ichar(cmd_mbc_buf, len));
1275 }
1276 
1277 /*
1278  * Return the number currently in the command buffer.
1279  */
1280 	public LINENUM
1281 cmd_int(frac)
1282 	long *frac;
1283 {
1284 	char *p;
1285 	LINENUM n = 0;
1286 	int err;
1287 
1288 	for (p = cmdbuf;  *p >= '0' && *p <= '9';  p++)
1289 		n = (n * 10) + (*p - '0');
1290 	*frac = 0;
1291 	if (*p++ == '.')
1292 	{
1293 		*frac = getfraction(&p, NULL, &err);
1294 		/* {{ do something if err is set? }} */
1295 	}
1296 	return (n);
1297 }
1298 
1299 /*
1300  * Return a pointer to the command buffer.
1301  */
1302 	public char *
1303 get_cmdbuf()
1304 {
1305 	return (cmdbuf);
1306 }
1307 
1308 #if CMD_HISTORY
1309 /*
1310  * Return the last (most recent) string in the current command history.
1311  */
1312 	public char *
1313 cmd_lastpattern()
1314 {
1315 	if (curr_mlist == NULL)
1316 		return (NULL);
1317 	return (curr_mlist->curr_mp->prev->string);
1318 }
1319 #endif
1320 
1321 #if CMD_HISTORY
1322 /*
1323  * Get the name of the history file.
1324  */
1325 	static char *
1326 histfile_name()
1327 {
1328 	char *home;
1329 	char *name;
1330 	int len;
1331 
1332 	/* See if filename is explicitly specified by $LESSHISTFILE. */
1333 	name = lgetenv("LESSHISTFILE");
1334 	if (name != NULL && *name != '\0')
1335 	{
1336 		if (strcmp(name, "-") == 0 || strcmp(name, "/dev/null") == 0)
1337 			/* $LESSHISTFILE == "-" means don't use a history file. */
1338 			return (NULL);
1339 		return (save(name));
1340 	}
1341 
1342 	/* Otherwise, file is in $HOME. */
1343 	home = lgetenv("HOME");
1344 	if (home == NULL || *home == '\0')
1345 	{
1346 #if OS2
1347 		home = lgetenv("INIT");
1348 		if (home == NULL || *home == '\0')
1349 #endif
1350 			return (NULL);
1351 	}
1352 	len = strlen(home) + strlen(LESSHISTFILE) + 2;
1353 	name = (char *) ecalloc(len, sizeof(char));
1354 	SNPRINTF2(name, len, "%s/%s", home, LESSHISTFILE);
1355 	return (name);
1356 }
1357 #endif /* CMD_HISTORY */
1358 
1359 /*
1360  * Initialize history from a .lesshist file.
1361  */
1362 	public void
1363 init_cmdhist()
1364 {
1365 #if CMD_HISTORY
1366 	struct mlist *ml = NULL;
1367 	char line[CMDBUF_SIZE];
1368 	char *filename;
1369 	FILE *f;
1370 	char *p;
1371 
1372 	filename = histfile_name();
1373 	if (filename == NULL)
1374 		return;
1375 	f = fopen(filename, "r");
1376 	free(filename);
1377 	if (f == NULL)
1378 		return;
1379 	if (fgets(line, sizeof(line), f) == NULL ||
1380 	    strncmp(line, HISTFILE_FIRST_LINE, strlen(HISTFILE_FIRST_LINE)) != 0)
1381 	{
1382 		fclose(f);
1383 		return;
1384 	}
1385 	while (fgets(line, sizeof(line), f) != NULL)
1386 	{
1387 		for (p = line;  *p != '\0';  p++)
1388 		{
1389 			if (*p == '\n' || *p == '\r')
1390 			{
1391 				*p = '\0';
1392 				break;
1393 			}
1394 		}
1395 		if (strcmp(line, HISTFILE_SEARCH_SECTION) == 0)
1396 			ml = &mlist_search;
1397 		else if (strcmp(line, HISTFILE_SHELL_SECTION) == 0)
1398 		{
1399 #if SHELL_ESCAPE || PIPEC
1400 			ml = &mlist_shell;
1401 #else
1402 			ml = NULL;
1403 #endif
1404 		} else if (*line == '"')
1405 		{
1406 			if (ml != NULL)
1407 				cmd_addhist(ml, line+1);
1408 		}
1409 	}
1410 	fclose(f);
1411 #endif /* CMD_HISTORY */
1412 }
1413 
1414 /*
1415  *
1416  */
1417 #if CMD_HISTORY
1418 	static void
1419 save_mlist(ml, f)
1420 	struct mlist *ml;
1421 	FILE *f;
1422 {
1423 	int histsize = 0;
1424 	int n;
1425 	char *s;
1426 
1427 	s = lgetenv("LESSHISTSIZE");
1428 	if (s != NULL)
1429 		histsize = atoi(s);
1430 	if (histsize == 0)
1431 		histsize = 100;
1432 
1433 	ml = ml->prev;
1434 	for (n = 0;  n < histsize;  n++)
1435 	{
1436 		if (ml->string == NULL)
1437 			break;
1438 		ml = ml->prev;
1439 	}
1440 	for (ml = ml->next;  ml->string != NULL;  ml = ml->next)
1441 		fprintf(f, "\"%s\n", ml->string);
1442 }
1443 #endif /* CMD_HISTORY */
1444 
1445 /*
1446  *
1447  */
1448 	public void
1449 save_cmdhist()
1450 {
1451 #if CMD_HISTORY
1452 	char *filename;
1453 	FILE *f;
1454 	int modified = 0;
1455 
1456 	filename = histfile_name();
1457 	if (filename == NULL)
1458 		return;
1459 	if (mlist_search.modified)
1460 		modified = 1;
1461 #if SHELL_ESCAPE || PIPEC
1462 	if (mlist_shell.modified)
1463 		modified = 1;
1464 #endif
1465 	if (!modified)
1466 		return;
1467 	f = fopen(filename, "w");
1468 	free(filename);
1469 	if (f == NULL)
1470 		return;
1471 #if HAVE_FCHMOD
1472 {
1473 	/* Make history file readable only by owner. */
1474 	int do_chmod = 1;
1475 #if HAVE_STAT
1476 	struct stat statbuf;
1477 	int r = fstat(fileno(f), &statbuf);
1478 	if (r < 0 || !S_ISREG(statbuf.st_mode))
1479 		/* Don't chmod if not a regular file. */
1480 		do_chmod = 0;
1481 #endif
1482 	if (do_chmod)
1483 		fchmod(fileno(f), 0600);
1484 }
1485 #endif
1486 
1487 	fprintf(f, "%s\n", HISTFILE_FIRST_LINE);
1488 
1489 	fprintf(f, "%s\n", HISTFILE_SEARCH_SECTION);
1490 	save_mlist(&mlist_search, f);
1491 
1492 #if SHELL_ESCAPE || PIPEC
1493 	fprintf(f, "%s\n", HISTFILE_SHELL_SECTION);
1494 	save_mlist(&mlist_shell, f);
1495 #endif
1496 
1497 	fclose(f);
1498 #endif /* CMD_HISTORY */
1499 }
1500