db_input.c revision 48810 
1/*
2 * Mach Operating System
3 * Copyright (c) 1991,1990 Carnegie Mellon University
4 * All Rights Reserved.
5 *
6 * Permission to use, copy, modify and distribute this software and its
7 * documentation is hereby granted, provided that both the copyright
8 * notice and this permission notice appear in all copies of the
9 * software, derivative works or modified versions, and any portions
10 * thereof, and that both notices appear in supporting documentation.
11 *
12 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
13 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
14 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
15 *
16 * Carnegie Mellon requests users of this software to return to
17 *
18 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
19 *  School of Computer Science
20 *  Carnegie Mellon University
21 *  Pittsburgh PA 15213-3890
22 *
23 * any improvements or extensions that they make and grant Carnegie the
24 * rights to redistribute these changes.
25 *
26 *	$Id: db_input.c,v 1.23 1997/12/05 05:36:58 dyson Exp $
27 */
28
29/*
30 *	Author: David B. Golub, Carnegie Mellon University
31 *	Date:	7/90
32 */
33
34#include <sys/param.h>
35#include <sys/systm.h>
36
37#include <machine/cons.h>
38
39#include <ddb/ddb.h>
40#include <ddb/db_output.h>
41
42/*
43 * Character input and editing.
44 */
45
46/*
47 * We don't track output position while editing input,
48 * since input always ends with a new-line.  We just
49 * reset the line position at the end.
50 */
51static char *	db_lbuf_start;	/* start of input line buffer */
52static char *	db_lbuf_end;	/* end of input line buffer */
53static char *	db_lc;		/* current character */
54static char *	db_le;		/* one past last character */
55
56/*
57 * Simple input line history support.
58 */
59static char	db_lhistory[2048];
60static int	db_lhistlsize, db_lhistidx, db_lhistcur;
61static int	db_lhist_nlines;
62
63#define	CTRL(c)		((c) & 0x1f)
64#define	isspace(c)	((c) == ' ' || (c) == '\t')
65#define	BLANK		' '
66#define	BACKUP		'\b'
67
68static int	cnmaygetc __P((void));
69static void	db_delete __P((int n, int bwd));
70static int	db_inputchar __P((int c));
71static void	db_putnchars __P((int c, int count));
72static void	db_putstring __P((char *s, int count));
73
74void
75db_putstring(s, count)
76	char	*s;
77	int	count;
78{
79	while (--count >= 0)
80	    cnputc(*s++);
81}
82
83void
84db_putnchars(c, count)
85	int	c;
86	int	count;
87{
88	while (--count >= 0)
89	    cnputc(c);
90}
91
92/*
93 * Delete N characters, forward or backward
94 */
95#define	DEL_FWD		0
96#define	DEL_BWD		1
97void
98db_delete(n, bwd)
99	int	n;
100	int	bwd;
101{
102	register char *p;
103
104	if (bwd) {
105	    db_lc -= n;
106	    db_putnchars(BACKUP, n);
107	}
108	for (p = db_lc; p < db_le-n; p++) {
109	    *p = *(p+n);
110	    cnputc(*p);
111	}
112	db_putnchars(BLANK, n);
113	db_putnchars(BACKUP, db_le - db_lc);
114	db_le -= n;
115}
116
117/* returns TRUE at end-of-line */
118int
119db_inputchar(c)
120	int	c;
121{
122	static int escstate;
123
124	if (escstate == 1) {
125		/* ESC seen, look for [ or O */
126		if (c == '[' || c == 'O')
127			escstate++;
128		else
129			escstate = 0; /* re-init state machine */
130		return (0);
131	} else if (escstate == 2) {
132		escstate = 0;
133		/*
134		 * If a valid cursor key has been found, translate
135		 * into an emacs-style control key, and fall through.
136		 * Otherwise, drop off.
137		 */
138		switch (c) {
139		case 'A':	/* up */
140			c = CTRL('p');
141			break;
142		case 'B':	/* down */
143			c = CTRL('n');
144			break;
145		case 'C':	/* right */
146			c = CTRL('f');
147			break;
148		case 'D':	/* left */
149			c = CTRL('b');
150			break;
151		default:
152			return (0);
153		}
154	}
155
156	switch (c) {
157	    case CTRL('['):
158		escstate = 1;
159		break;
160	    case CTRL('b'):
161		/* back up one character */
162		if (db_lc > db_lbuf_start) {
163		    cnputc(BACKUP);
164		    db_lc--;
165		}
166		break;
167	    case CTRL('f'):
168		/* forward one character */
169		if (db_lc < db_le) {
170		    cnputc(*db_lc);
171		    db_lc++;
172		}
173		break;
174	    case CTRL('a'):
175		/* beginning of line */
176		while (db_lc > db_lbuf_start) {
177		    cnputc(BACKUP);
178		    db_lc--;
179		}
180		break;
181	    case CTRL('e'):
182		/* end of line */
183		while (db_lc < db_le) {
184		    cnputc(*db_lc);
185		    db_lc++;
186		}
187		break;
188	    case CTRL('h'):
189	    case 0177:
190		/* erase previous character */
191		if (db_lc > db_lbuf_start)
192		    db_delete(1, DEL_BWD);
193		break;
194	    case CTRL('d'):
195		/* erase next character */
196		if (db_lc < db_le)
197		    db_delete(1, DEL_FWD);
198		break;
199	    case CTRL('k'):
200		/* delete to end of line */
201		if (db_lc < db_le)
202		    db_delete(db_le - db_lc, DEL_FWD);
203		break;
204	    case CTRL('t'):
205		/* twiddle last 2 characters */
206		if (db_lc >= db_lbuf_start + 2) {
207		    c = db_lc[-2];
208		    db_lc[-2] = db_lc[-1];
209		    db_lc[-1] = c;
210		    cnputc(BACKUP);
211		    cnputc(BACKUP);
212		    cnputc(db_lc[-2]);
213		    cnputc(db_lc[-1]);
214		}
215		break;
216	    case CTRL('r'):
217		db_putstring("^R\n", 3);
218	    redraw:
219		if (db_le > db_lbuf_start) {
220		    db_putstring(db_lbuf_start, db_le - db_lbuf_start);
221		    db_putnchars(BACKUP, db_le - db_lc);
222		}
223		break;
224	    case CTRL('p'):
225		/* Make previous history line the active one. */
226		if (db_lhistcur >= 0) {
227		    bcopy(db_lhistory + db_lhistcur * db_lhistlsize,
228			  db_lbuf_start, db_lhistlsize);
229		    db_lhistcur--;
230		    goto hist_redraw;
231		}
232		break;
233	    case CTRL('n'):
234		/* Make next history line the active one. */
235		if (db_lhistcur < db_lhistidx - 1) {
236		    db_lhistcur += 2;
237		    bcopy(db_lhistory + db_lhistcur * db_lhistlsize,
238			  db_lbuf_start, db_lhistlsize);
239		} else {
240		    /*
241		     * ^N through tail of history, reset the
242		     * buffer to zero length.
243		     */
244		    *db_lbuf_start = '\0';
245		    db_lhistcur = db_lhistidx;
246		}
247
248	    hist_redraw:
249		db_putnchars(BACKUP, db_le - db_lbuf_start);
250		db_putnchars(BLANK, db_le - db_lbuf_start);
251		db_putnchars(BACKUP, db_le - db_lbuf_start);
252		db_le = index(db_lbuf_start, '\0');
253		if (db_le[-1] == '\r' || db_le[-1] == '\n')
254		    *--db_le = '\0';
255		db_lc = db_le;
256		goto redraw;
257
258	    case -1:
259		/*
260		 * eek! the console returned eof.
261		 * probably that means we HAVE no console.. we should try bail
262		 * XXX
263		 */
264		c = '\r';
265	    case '\n':
266	    case '\r':
267		*db_le++ = c;
268		return (1);
269	    default:
270		if (db_le == db_lbuf_end) {
271		    cnputc('\007');
272		}
273		else if (c >= ' ' && c <= '~') {
274		    register char *p;
275
276		    for (p = db_le; p > db_lc; p--)
277			*p = *(p-1);
278		    *db_lc++ = c;
279		    db_le++;
280		    cnputc(c);
281		    db_putstring(db_lc, db_le - db_lc);
282		    db_putnchars(BACKUP, db_le - db_lc);
283		}
284		break;
285	}
286	return (0);
287}
288
289int
290cnmaygetc()
291{
292	return (-1);
293}
294
295int
296db_readline(lstart, lsize)
297	char *	lstart;
298	int	lsize;
299{
300	if (lsize != db_lhistlsize) {
301		/*
302		 * (Re)initialize input line history.  Throw away any
303		 * existing history.
304		 */
305		db_lhist_nlines = sizeof(db_lhistory) / lsize;
306		db_lhistlsize = lsize;
307		db_lhistidx = -1;
308	}
309	db_lhistcur = db_lhistidx;
310
311	db_force_whitespace();	/* synch output position */
312
313	db_lbuf_start = lstart;
314	db_lbuf_end   = lstart + lsize;
315	db_lc = lstart;
316	db_le = lstart;
317
318	while (!db_inputchar(cngetc()))
319	    continue;
320
321	db_printf("\n");	/* synch output position */
322	*db_le = 0;
323
324	if (db_le - db_lbuf_start > 1) {
325	    /* Maintain input line history for non-empty lines. */
326	    if (++db_lhistidx == db_lhist_nlines) {
327		/* Rotate history. */
328		ovbcopy(db_lhistory + db_lhistlsize, db_lhistory,
329			db_lhistlsize * (db_lhist_nlines - 1));
330		db_lhistidx--;
331	    }
332	    bcopy(lstart, db_lhistory + db_lhistidx * db_lhistlsize,
333		  db_lhistlsize);
334	}
335
336	return (db_le - db_lbuf_start);
337}
338
339void
340db_check_interrupt()
341{
342	register int	c;
343
344	c = cnmaygetc();
345	switch (c) {
346	    case -1:		/* no character */
347		return;
348
349	    case CTRL('c'):
350		db_error((char *)0);
351		/*NOTREACHED*/
352
353	    case CTRL('s'):
354		do {
355		    c = cnmaygetc();
356		    if (c == CTRL('c'))
357			db_error((char *)0);
358		} while (c != CTRL('q'));
359		break;
360
361	    default:
362		/* drop on floor */
363		break;
364	}
365}
366
367/* called from kdb_trap in db_interface.c */
368void
369cnpollc (flag)
370	int flag;
371{
372}
373