aboutsummaryrefslogtreecommitdiffstats
path: root/common/key.c
blob: e71396893fd483dda9d5268bcae58008575531a2 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
/*-
 * Copyright (c) 1991, 1993, 1994
 *	The Regents of the University of California.  All rights reserved.
 * Copyright (c) 1991, 1993, 1994, 1995, 1996
 *	Keith Bostic.  All rights reserved.
 *
 * See the LICENSE file for redistribution information.
 */

#include "config.h"

#include <sys/types.h>
#include <sys/queue.h>
#include <sys/time.h>

#include <bitstring.h>
#include <ctype.h>
#include <errno.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <unistd.h>

#include "common.h"
#include "../vi/vi.h"

static int	v_event_append(SCR *, EVENT *);
static int	v_event_grow(SCR *, int);
static int	v_key_cmp(const void *, const void *);
static void	v_keyval(SCR *, int, scr_keyval_t);
static void	v_sync(SCR *, int);

/*
 * !!!
 * Historic vi always used:
 *
 *	^D: autoindent deletion
 *	^H: last character deletion
 *	^W: last word deletion
 *	^Q: quote the next character (if not used in flow control).
 *	^V: quote the next character
 *
 * regardless of the user's choices for these characters.  The user's erase
 * and kill characters worked in addition to these characters.  Nvi wires
 * down the above characters, but in addition permits the VEOF, VERASE, VKILL
 * and VWERASE characters described by the user's termios structure.
 *
 * Ex was not consistent with this scheme, as it historically ran in tty
 * cooked mode.  This meant that the scroll command and autoindent erase
 * characters were mapped to the user's EOF character, and the character
 * and word deletion characters were the user's tty character and word
 * deletion characters.  This implementation makes it all consistent, as
 * described above for vi.
 *
 * !!!
 * This means that all screens share a special key set.
 */
KEYLIST keylist[] = {
	{K_BACKSLASH,	  '\\'},	/*  \ */
	{K_CARAT,	   '^'},	/*  ^ */
	{K_CNTRLD,	'\004'},	/* ^D */
	{K_CNTRLR,	'\022'},	/* ^R */
	{K_CNTRLT,	'\024'},	/* ^T */
	{K_CNTRLZ,	'\032'},	/* ^Z */
	{K_COLON,	   ':'},	/*  : */
	{K_CR,		  '\r'},	/* \r */
	{K_ESCAPE,	'\033'},	/* ^[ */
	{K_FORMFEED,	  '\f'},	/* \f */
	{K_HEXCHAR,	'\030'},	/* ^X */
	{K_NL,		  '\n'},	/* \n */
	{K_RIGHTBRACE,	   '}'},	/*  } */
	{K_RIGHTPAREN,	   ')'},	/*  ) */
	{K_TAB,		  '\t'},	/* \t */
	{K_VERASE,	  '\b'},	/* \b */
	{K_VKILL,	'\025'},	/* ^U */
	{K_VLNEXT,	'\021'},	/* ^Q */
	{K_VLNEXT,	'\026'},	/* ^V */
	{K_VWERASE,	'\027'},	/* ^W */
	{K_ZERO,	   '0'},	/*  0 */

#define	ADDITIONAL_CHARACTERS	4
	{K_NOTUSED, 0},			/* VEOF, VERASE, VKILL, VWERASE */
	{K_NOTUSED, 0},
	{K_NOTUSED, 0},
	{K_NOTUSED, 0},
};
static int nkeylist =
    (sizeof(keylist) / sizeof(keylist[0])) - ADDITIONAL_CHARACTERS;

/*
 * v_key_init --
 *	Initialize the special key lookup table.
 *
 * PUBLIC: int v_key_init(SCR *);
 */
int
v_key_init(SCR *sp)
{
	int ch;
	GS *gp;
	KEYLIST *kp;
	int cnt;

	gp = sp->gp;

	v_key_ilookup(sp);

	v_keyval(sp, K_CNTRLD, KEY_VEOF);
	v_keyval(sp, K_VERASE, KEY_VERASE);
	v_keyval(sp, K_VKILL, KEY_VKILL);
	v_keyval(sp, K_VWERASE, KEY_VWERASE);

	/* Sort the special key list. */
	qsort(keylist, nkeylist, sizeof(keylist[0]), v_key_cmp);

	/* Initialize the fast lookup table. */
	for (kp = keylist, cnt = nkeylist; cnt--; ++kp)
		gp->special_key[kp->ch] = kp->value;

	/* Find a non-printable character to use as a message separator. */
	for (ch = 1; ch <= UCHAR_MAX; ++ch)
		if (!isprint(ch)) {
			gp->noprint = ch;
			break;
		}
	if (ch != gp->noprint) {
		msgq(sp, M_ERR, "079|No non-printable character found");
		return (1);
	}
	return (0);
}

/*
 * v_keyval --
 *	Set key values.
 *
 * We've left some open slots in the keylist table, and if these values exist,
 * we put them into place.  Note, they may reset (or duplicate) values already
 * in the table, so we check for that first.
 */
static void
v_keyval(SCR *sp, int val, scr_keyval_t name)
{
	KEYLIST *kp;
	CHAR_T ch;
	int dne;

	/* Get the key's value from the screen. */
	if (sp->gp->scr_keyval(sp, name, &ch, &dne))
		return;
	if (dne)
		return;

	/* Check for duplication. */
	for (kp = keylist; kp->value != K_NOTUSED; ++kp)
		if (kp->ch == ch) {
			kp->value = val;
			return;
		}

	/* Add a new entry. */
	if (kp->value == K_NOTUSED) {
		keylist[nkeylist].ch = ch;
		keylist[nkeylist].value = val;
		++nkeylist;
	}
}

/*
 * v_key_ilookup --
 *	Build the fast-lookup key display array.
 *
 * PUBLIC: void v_key_ilookup(SCR *);
 */
void
v_key_ilookup(SCR *sp)
{
	UCHAR_T ch;
	char *p, *t;
	GS *gp;
	size_t len;

	for (gp = sp->gp, ch = 0;; ++ch) {
		for (p = gp->cname[ch].name, t = v_key_name(sp, ch),
		    len = gp->cname[ch].len = sp->clen; len--;)
			*p++ = *t++;
		if (ch == MAX_FAST_KEY)
			break;
	}
}

/*
 * v_key_len --
 *	Return the length of the string that will display the key.
 *	This routine is the backup for the KEY_LEN() macro.
 *
 * PUBLIC: size_t v_key_len(SCR *, ARG_CHAR_T);
 */
size_t
v_key_len(SCR *sp, ARG_CHAR_T ch)
{
	(void)v_key_name(sp, ch);
	return (sp->clen);
}

/*
 * v_key_name --
 *	Return the string that will display the key.  This routine
 *	is the backup for the KEY_NAME() macro.
 *
 * PUBLIC: char *v_key_name(SCR *, ARG_CHAR_T);
 */
char *
v_key_name(SCR *sp, ARG_CHAR_T ach)
{
	static const char hexdigit[] = "0123456789abcdef";
	static const char octdigit[] = "01234567";
	int ch;
	size_t len;
	char *chp;

	/*
	 * Cache the last checked character.  It won't be a problem
	 * since nvi will rescan the mapping when settings changed.
	 */
	if (ach && sp->lastc == ach)
		return (sp->cname);
	sp->lastc = ach;

#ifdef USE_WIDECHAR
	len = wctomb(sp->cname, ach);
	if (len > MB_CUR_MAX)
#endif
		sp->cname[(len = 1)-1] = (u_char)ach;

	ch = (u_char)sp->cname[0];
	sp->cname[len] = '\0';

	/* See if the character was explicitly declared printable or not. */
	if ((chp = O_STR(sp, O_PRINT)) != NULL)
		if (strstr(chp, sp->cname) != NULL)
			goto done;
	if ((chp = O_STR(sp, O_NOPRINT)) != NULL)
		if (strstr(chp, sp->cname) != NULL)
			goto nopr;

	/*
	 * Historical (ARPA standard) mappings.  Printable characters are left
	 * alone.  Control characters less than 0x20 are represented as '^'
	 * followed by the character offset from the '@' character in the ASCII
	 * character set.  Del (0x7f) is represented as '^' followed by '?'.
	 *
	 * XXX
	 * The following code depends on the current locale being identical to
	 * the ASCII map from 0x40 to 0x5f (since 0x1f + 0x40 == 0x5f).  I'm
	 * told that this is a reasonable assumption...
	 *
	 * XXX
	 * The code prints non-printable wide characters in 4 or 5 digits
	 * Unicode escape sequences, so only supports plane 0 to 15.
	 */
	if (CAN_PRINT(sp, ach))
		goto done;
nopr:	if (iscntrl(ch) && (ch < 0x20 || ch == 0x7f)) {
		sp->cname[0] = '^';
		sp->cname[1] = ch == 0x7f ? '?' : '@' + ch;
		len = 2;
		goto done;
	}
#ifdef USE_WIDECHAR
	if (INTISWIDE(ach)) {
		int uc = -1;

		if (!strcmp(codeset(), "UTF-8"))
			uc = decode_utf8(sp->cname);
#ifdef USE_ICONV
		else {
			char buf[sizeof(sp->cname)] = "";
			size_t left = sizeof(sp->cname);
			char *in = sp->cname;
			char *out = buf;
			iconv(sp->conv.id[IC_IE_TO_UTF16],
			    (iconv_src_t)&in, &len, &out, &left);
			iconv(sp->conv.id[IC_IE_TO_UTF16],
			    NULL, NULL, NULL, NULL);
			uc = decode_utf16(buf, 1);
		}
#endif
		if (uc >= 0) {
			len = snprintf(sp->cname, sizeof(sp->cname),
			    uc < 0x10000 ? "\\u%04x" : "\\U%05X", uc);
			goto done;
		}
	}
#endif
	if (O_ISSET(sp, O_OCTAL)) {
		sp->cname[0] = '\\';
		sp->cname[1] = octdigit[(ch & 0300) >> 6];
		sp->cname[2] = octdigit[(ch &  070) >> 3];
		sp->cname[3] = octdigit[ ch &   07      ];
	} else {
		sp->cname[0] = '\\';
		sp->cname[1] = 'x';
		sp->cname[2] = hexdigit[(ch & 0xf0) >> 4];
		sp->cname[3] = hexdigit[ ch & 0x0f      ];
	}
	len = 4;
done:	sp->cname[sp->clen = len] = '\0';
	return (sp->cname);
}

/*
 * v_key_val --
 *	Fill in the value for a key.  This routine is the backup
 *	for the KEY_VAL() macro.
 *
 * PUBLIC: e_key_t v_key_val(SCR *, ARG_CHAR_T);
 */
e_key_t
v_key_val(SCR *sp, ARG_CHAR_T ch)
{
	KEYLIST k, *kp;

	k.ch = ch;
	kp = bsearch(&k, keylist, nkeylist, sizeof(keylist[0]), v_key_cmp);
	return (kp == NULL ? K_NOTUSED : kp->value);
}

/*
 * v_event_push --
 *	Push events/keys onto the front of the buffer.
 *
 * There is a single input buffer in ex/vi.  Characters are put onto the
 * end of the buffer by the terminal input routines, and pushed onto the
 * front of the buffer by various other functions in ex/vi.  Each key has
 * an associated flag value, which indicates if it has already been quoted,
 * and if it is the result of a mapping or an abbreviation.
 *
 * PUBLIC: int v_event_push(SCR *, EVENT *, CHAR_T *, size_t, u_int);
 */
int
v_event_push(SCR *sp,
	EVENT *p_evp,			/* Push event. */
	CHAR_T *p_s,			/* Push characters. */
	size_t nitems,			/* Number of items to push. */
	u_int flags)			/* CH_* flags. */
{
	EVENT *evp;
	GS *gp;
	size_t total;

	/* If we have room, stuff the items into the buffer. */
	gp = sp->gp;
	if (nitems <= gp->i_next ||
	    (gp->i_event != NULL && gp->i_cnt == 0 && nitems <= gp->i_nelem)) {
		if (gp->i_cnt != 0)
			gp->i_next -= nitems;
		goto copy;
	}

	/*
	 * If there are currently items in the queue, shift them up,
	 * leaving some extra room.  Get enough space plus a little
	 * extra.
	 */
#define	TERM_PUSH_SHIFT	30
	total = gp->i_cnt + gp->i_next + nitems + TERM_PUSH_SHIFT;
	if (total >= gp->i_nelem && v_event_grow(sp, MAX(total, 64)))
		return (1);
	if (gp->i_cnt)
		memmove(gp->i_event + TERM_PUSH_SHIFT + nitems,
		    gp->i_event + gp->i_next, gp->i_cnt * sizeof(EVENT));
	gp->i_next = TERM_PUSH_SHIFT;

	/* Put the new items into the queue. */
copy:	gp->i_cnt += nitems;
	for (evp = gp->i_event + gp->i_next; nitems--; ++evp) {
		if (p_evp != NULL)
			*evp = *p_evp++;
		else {
			evp->e_event = E_CHARACTER;
			evp->e_c = *p_s++;
			evp->e_value = KEY_VAL(sp, evp->e_c);
			F_INIT(&evp->e_ch, flags);
		}
	}
	return (0);
}

/*
 * v_event_append --
 *	Append events onto the tail of the buffer.
 */
static int
v_event_append(SCR *sp, EVENT *argp)
{
	CHAR_T *s;			/* Characters. */
	EVENT *evp;
	GS *gp;
	size_t nevents;			/* Number of events. */

	/* Grow the buffer as necessary. */
	nevents = argp->e_event == E_STRING ? argp->e_len : 1;
	gp = sp->gp;
	if (gp->i_event == NULL ||
	    nevents > gp->i_nelem - (gp->i_next + gp->i_cnt))
		v_event_grow(sp, MAX(nevents, 64));
	evp = gp->i_event + gp->i_next + gp->i_cnt;
	gp->i_cnt += nevents;

	/* Transform strings of characters into single events. */
	if (argp->e_event == E_STRING)
		for (s = argp->e_csp; nevents--; ++evp) {
			evp->e_event = E_CHARACTER;
			evp->e_c = *s++;
			evp->e_value = KEY_VAL(sp, evp->e_c);
			evp->e_flags = 0;
		}
	else
		*evp = *argp;
	return (0);
}

/* Remove events from the queue. */
#define	QREM(len) do {							\
	if ((gp->i_cnt -= len) == 0)					\
		gp->i_next = 0;						\
	else								\
		gp->i_next += len;					\
} while (0)

/*
 * v_event_get --
 *	Return the next event.
 *
 * !!!
 * The flag EC_NODIGIT probably needs some explanation.  First, the idea of
 * mapping keys is that one or more keystrokes act like a function key.
 * What's going on is that vi is reading a number, and the character following
 * the number may or may not be mapped (EC_MAPCOMMAND).  For example, if the
 * user is entering the z command, a valid command is "z40+", and we don't want
 * to map the '+', i.e. if '+' is mapped to "xxx", we don't want to change it
 * into "z40xxx".  However, if the user enters "35x", we want to put all of the
 * characters through the mapping code.
 *
 * Historical practice is a bit muddled here.  (Surprise!)  It always permitted
 * mapping digits as long as they weren't the first character of the map, e.g.
 * ":map ^A1 xxx" was okay.  It also permitted the mapping of the digits 1-9
 * (the digit 0 was a special case as it doesn't indicate the start of a count)
 * as the first character of the map, but then ignored those mappings.  While
 * it's probably stupid to map digits, vi isn't your mother.
 *
 * The way this works is that the EC_MAPNODIGIT causes term_key to return the
 * end-of-digit without "looking" at the next character, i.e. leaving it as the
 * user entered it.  Presumably, the next term_key call will tell us how the
 * user wants it handled.
 *
 * There is one more complication.  Users might map keys to digits, and, as
 * it's described above, the commands:
 *
 *	:map g 1G
 *	d2g
 *
 * would return the keys "d2<end-of-digits>1G", when the user probably wanted
 * "d21<end-of-digits>G".  So, if a map starts off with a digit we continue as
 * before, otherwise, we pretend we haven't mapped the character, and return
 * <end-of-digits>.
 *
 * Now that that's out of the way, let's talk about Energizer Bunny macros.
 * It's easy to create macros that expand to a loop, e.g. map x 3x.  It's
 * fairly easy to detect this example, because it's all internal to term_key.
 * If we're expanding a macro and it gets big enough, at some point we can
 * assume it's looping and kill it.  The examples that are tough are the ones
 * where the parser is involved, e.g. map x "ayyx"byy.  We do an expansion
 * on 'x', and get "ayyx"byy.  We then return the first 4 characters, and then
 * find the looping macro again.  There is no way that we can detect this
 * without doing a full parse of the command, because the character that might
 * cause the loop (in this case 'x') may be a literal character, e.g. the map
 * map x "ayy"xyy"byy is perfectly legal and won't cause a loop.
 *
 * Historic vi tried to detect looping macros by disallowing obvious cases in
 * the map command, maps that that ended with the same letter as they started
 * (which wrongly disallowed "map x 'x"), and detecting macros that expanded
 * too many times before keys were returned to the command parser.  It didn't
 * get many (most?) of the tricky cases right, however, and it was certainly
 * possible to create macros that ran forever.  And, even if it did figure out
 * what was going on, the user was usually tossed into ex mode.  Finally, any
 * changes made before vi realized that the macro was recursing were left in
 * place.  We recover gracefully, but the only recourse the user has in an
 * infinite macro loop is to interrupt.
 *
 * !!!
 * It is historic practice that mapping characters to themselves as the first
 * part of the mapped string was legal, and did not cause infinite loops, i.e.
 * ":map! { {^M^T" and ":map n nz." were known to work.  The initial, matching
 * characters were returned instead of being remapped.
 *
 * !!!
 * It is also historic practice that the macro "map ] ]]^" caused a single ]
 * keypress to behave as the command ]] (the ^ got the map past the vi check
 * for "tail recursion").  Conversely, the mapping "map n nn^" went recursive.
 * What happened was that, in the historic vi, maps were expanded as the keys
 * were retrieved, but not all at once and not centrally.  So, the keypress ]
 * pushed ]]^ on the stack, and then the first ] from the stack was passed to
 * the ]] command code.  The ]] command then retrieved a key without entering
 * the mapping code.  This could bite us anytime a user has a map that depends
 * on secondary keys NOT being mapped.  I can't see any possible way to make
 * this work in here without the complete abandonment of Rationality Itself.
 *
 * XXX
 * The final issue is recovery.  It would be possible to undo all of the work
 * that was done by the macro if we entered a record into the log so that we
 * knew when the macro started, and, in fact, this might be worth doing at some
 * point.  Given that this might make the log grow unacceptably (consider that
 * cursor keys are done with maps), for now we leave any changes made in place.
 *
 * PUBLIC: int v_event_get(SCR *, EVENT *, int, u_int32_t);
 */
int
v_event_get(SCR *sp, EVENT *argp, int timeout, u_int32_t flags)
{
	EVENT *evp, ev;
	GS *gp;
	SEQ *qp;
	int init_nomap, ispartial, istimeout, remap_cnt;

	gp = sp->gp;

	/* If simply checking for interrupts, argp may be NULL. */
	if (argp == NULL)
		argp = &ev;

retry:	istimeout = remap_cnt = 0;

	/*
	 * If the queue isn't empty and we're timing out for characters,
	 * return immediately.
	 */
	if (gp->i_cnt != 0 && LF_ISSET(EC_TIMEOUT))
		return (0);

	/*
	 * If the queue is empty, we're checking for interrupts, or we're
	 * timing out for characters, get more events.
	 */
	if (gp->i_cnt == 0 || LF_ISSET(EC_INTERRUPT | EC_TIMEOUT)) {
		/*
		 * If we're reading new characters, check any scripting
		 * windows for input.
		 */
		if (F_ISSET(gp, G_SCRWIN) && sscr_input(sp))
			return (1);
loop:		if (gp->scr_event(sp, argp,
		    LF_ISSET(EC_INTERRUPT | EC_QUOTED | EC_RAW), timeout))
			return (1);
		switch (argp->e_event) {
		case E_ERR:
		case E_SIGHUP:
		case E_SIGTERM:
			/*
			 * Fatal conditions cause the file to be synced to
			 * disk immediately.
			 */
			v_sync(sp, RCV_ENDSESSION | RCV_PRESERVE |
			    (argp->e_event == E_SIGTERM ? 0: RCV_EMAIL));
			return (1);
		case E_TIMEOUT:
			istimeout = 1;
			break;
		case E_INTERRUPT:
			/* Set the global interrupt flag. */
			F_SET(sp->gp, G_INTERRUPTED);

			/*
			 * If the caller was interested in interrupts, return
			 * immediately.
			 */
			if (LF_ISSET(EC_INTERRUPT))
				return (0);
			goto append;
		default:
append:			if (v_event_append(sp, argp))
				return (1);
			break;
		}
	}

	/*
	 * If the caller was only interested in interrupts or timeouts, return
	 * immediately.  (We may have gotten characters, and that's okay, they
	 * were queued up for later use.)
	 */
	if (LF_ISSET(EC_INTERRUPT | EC_TIMEOUT))
		return (0);
	 
newmap:	evp = &gp->i_event[gp->i_next];

	/* 
	 * If the next event in the queue isn't a character event, return
	 * it, we're done.
	 */
	if (evp->e_event != E_CHARACTER) {
		*argp = *evp;
		QREM(1);
		return (0);
	}
	
	/*
	 * If the key isn't mappable because:
	 *
	 *	+ ... the timeout has expired
	 *	+ ... it's not a mappable key
	 *	+ ... neither the command or input map flags are set
	 *	+ ... there are no maps that can apply to it
	 *
	 * return it forthwith.
	 */
	if (istimeout || F_ISSET(&evp->e_ch, CH_NOMAP) ||
	    !LF_ISSET(EC_MAPCOMMAND | EC_MAPINPUT) ||
	    ((evp->e_c & ~MAX_BIT_SEQ) == 0 &&
	    !bit_test(gp->seqb, evp->e_c)))
		goto nomap;

	/* Search the map. */
	qp = seq_find(sp, NULL, evp, NULL, gp->i_cnt,
	    LF_ISSET(EC_MAPCOMMAND) ? SEQ_COMMAND : SEQ_INPUT, &ispartial);

	/*
	 * If get a partial match, get more characters and retry the map.
	 * If time out without further characters, return the characters
	 * unmapped.
	 *
	 * !!!
	 * <escape> characters are a problem.  Cursor keys start with <escape>
	 * characters, so there's almost always a map in place that begins with
	 * an <escape> character.  If we timeout <escape> keys in the same way
	 * that we timeout other keys, the user will get a noticeable pause as
	 * they enter <escape> to terminate input mode.  If key timeout is set
	 * for a slow link, users will get an even longer pause.  Nvi used to
	 * simply timeout <escape> characters at 1/10th of a second, but this
	 * loses over PPP links where the latency is greater than 100Ms.
	 */
	if (ispartial) {
		if (O_ISSET(sp, O_TIMEOUT))
			timeout = (evp->e_value == K_ESCAPE ?
			    O_VAL(sp, O_ESCAPETIME) :
			    O_VAL(sp, O_KEYTIME)) * 100;
		else
			timeout = 0;
		goto loop;
	}

	/* If no map, return the character. */
	if (qp == NULL) {
nomap:		if (!ISDIGIT(evp->e_c) && LF_ISSET(EC_MAPNODIGIT))
			goto not_digit;
		*argp = *evp;
		QREM(1);
		return (0);
	}

	/*
	 * If looking for the end of a digit string, and the first character
	 * of the map is it, pretend we haven't seen the character.
	 */
	if (LF_ISSET(EC_MAPNODIGIT) &&
	    qp->output != NULL && !ISDIGIT(qp->output[0])) {
not_digit:	argp->e_c = CH_NOT_DIGIT;
		argp->e_value = K_NOTUSED;
		argp->e_event = E_CHARACTER;
		F_INIT(&argp->e_ch, 0);
		return (0);
	}

	/* Find out if the initial segments are identical. */
	init_nomap = !e_memcmp(qp->output, &gp->i_event[gp->i_next], qp->ilen);

	/* Delete the mapped characters from the queue. */
	QREM(qp->ilen);

	/* If keys mapped to nothing, go get more. */
	if (qp->output == NULL)
		goto retry;

	/* If remapping characters... */
	if (O_ISSET(sp, O_REMAP)) {
		/*
		 * Periodically check for interrupts.  Always check the first
		 * time through, because it's possible to set up a map that
		 * will return a character every time, but will expand to more,
		 * e.g. "map! a aaaa" will always return a 'a', but we'll never
		 * get anywhere useful.
		 */
		if ((++remap_cnt == 1 || remap_cnt % 10 == 0) &&
		    (gp->scr_event(sp, &ev,
		    EC_INTERRUPT, 0) || ev.e_event == E_INTERRUPT)) {
			F_SET(sp->gp, G_INTERRUPTED);
			argp->e_event = E_INTERRUPT;
			return (0);
		}

		/*
		 * If an initial part of the characters mapped, they are not
		 * further remapped -- return the first one.  Push the rest
		 * of the characters, or all of the characters if no initial
		 * part mapped, back on the queue.
		 */
		if (init_nomap) {
			if (v_event_push(sp, NULL, qp->output + qp->ilen,
			    qp->olen - qp->ilen, CH_MAPPED))
				return (1);
			if (v_event_push(sp, NULL,
			    qp->output, qp->ilen, CH_NOMAP | CH_MAPPED))
				return (1);
			evp = &gp->i_event[gp->i_next];
			goto nomap;
		}
		if (v_event_push(sp, NULL, qp->output, qp->olen, CH_MAPPED))
			return (1);
		goto newmap;
	}

	/* Else, push the characters on the queue and return one. */
	if (v_event_push(sp, NULL, qp->output, qp->olen, CH_MAPPED | CH_NOMAP))
		return (1);

	goto nomap;
}

/*
 * v_sync --
 *	Walk the screen lists, sync'ing files to their backup copies.
 */
static void
v_sync(SCR *sp, int flags)
{
	GS *gp;

	gp = sp->gp;
	TAILQ_FOREACH(sp, gp->dq, q)
		rcv_sync(sp, flags);
	TAILQ_FOREACH(sp, gp->hq, q)
		rcv_sync(sp, flags);
}

/*
 * v_event_err --
 *	Unexpected event.
 *
 * PUBLIC: void v_event_err(SCR *, EVENT *);
 */
void
v_event_err(SCR *sp, EVENT *evp)
{
	switch (evp->e_event) {
	case E_CHARACTER:
		msgq(sp, M_ERR, "276|Unexpected character event");
		break;
	case E_EOF:
		msgq(sp, M_ERR, "277|Unexpected end-of-file event");
		break;
	case E_INTERRUPT:
		msgq(sp, M_ERR, "279|Unexpected interrupt event");
		break;
	case E_REPAINT:
		msgq(sp, M_ERR, "281|Unexpected repaint event");
		break;
	case E_STRING:
		msgq(sp, M_ERR, "285|Unexpected string event");
		break;
	case E_TIMEOUT:
		msgq(sp, M_ERR, "286|Unexpected timeout event");
		break;
	case E_WRESIZE:
		msgq(sp, M_ERR, "316|Unexpected resize event");
		break;

	/*
	 * Theoretically, none of these can occur, as they're handled at the
	 * top editor level.
	 */
	case E_ERR:
	case E_SIGHUP:
	case E_SIGTERM:
	default:
		abort();
	}

	/* Free any allocated memory. */
	free(evp->e_asp);
}

/*
 * v_event_flush --
 *	Flush any flagged keys, returning if any keys were flushed.
 *
 * PUBLIC: int v_event_flush(SCR *, u_int);
 */
int
v_event_flush(SCR *sp, u_int flags)
{
	GS *gp;
	int rval;

	for (rval = 0, gp = sp->gp; gp->i_cnt != 0 &&
	    F_ISSET(&gp->i_event[gp->i_next].e_ch, flags); rval = 1)
		QREM(1);
	return (rval);
}

/*
 * v_event_grow --
 *	Grow the terminal queue.
 */
static int
v_event_grow(SCR *sp, int add)
{
	GS *gp;
	size_t new_nelem, olen;

	gp = sp->gp;
	new_nelem = gp->i_nelem + add;
	olen = gp->i_nelem * sizeof(gp->i_event[0]);
	BINC_RET(sp, EVENT, gp->i_event, olen, new_nelem * sizeof(gp->i_event[0]));
	gp->i_nelem = olen / sizeof(gp->i_event[0]);
	return (0);
}

/*
 * v_key_cmp --
 *	Compare two keys for sorting.
 */
static int
v_key_cmp(const void *ap, const void *bp)
{
	return (((KEYLIST *)ap)->ch - ((KEYLIST *)bp)->ch);
}