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/*
27 *	Author: David B. Golub, Carnegie Mellon University
28 *	Date:	7/90
29 */
30
31#include <sys/cdefs.h>
32__FBSDID("$FreeBSD$");
33
34#include <sys/param.h>
35#include <sys/systm.h>
36#include <sys/cons.h>
37
38#include <ddb/ddb.h>
39#include <ddb/db_output.h>
40
41/*
42 * Character input and editing.
43 */
44
45/*
46 * We don't track output position while editing input,
47 * since input always ends with a new-line.  We just
48 * reset the line position at the end.
49 */
50static char *	db_lbuf_start;	/* start of input line buffer */
51static char *	db_lbuf_end;	/* end of input line buffer */
52static char *	db_lc;		/* current character */
53static char *	db_le;		/* one past last character */
54
55/*
56 * Simple input line history support.
57 */
58static char	db_lhistory[2048];
59static int	db_lhistlsize, db_lhistidx, db_lhistcur;
60static int	db_lhist_nlines;
61
62#define	CTRL(c)		((c) & 0x1f)
63#define	BLANK		' '
64#define	BACKUP		'\b'
65
66static int	cnmaygetc(void);
67static void	db_delete(int n, int bwd);
68static int	db_inputchar(int c);
69static void	db_putnchars(int c, int count);
70static void	db_putstring(char *s, int count);
71
72static void
73db_putstring(s, count)
74	char	*s;
75	int	count;
76{
77	while (--count >= 0)
78	    cnputc(*s++);
79}
80
81static void
82db_putnchars(c, count)
83	int	c;
84	int	count;
85{
86	while (--count >= 0)
87	    cnputc(c);
88}
89
90/*
91 * Delete N characters, forward or backward
92 */
93#define	DEL_FWD		0
94#define	DEL_BWD		1
95static void
96db_delete(n, bwd)
97	int	n;
98	int	bwd;
99{
100	register char *p;
101
102	if (bwd) {
103	    db_lc -= n;
104	    db_putnchars(BACKUP, n);
105	}
106	for (p = db_lc; p < db_le-n; p++) {
107	    *p = *(p+n);
108	    cnputc(*p);
109	}
110	db_putnchars(BLANK, n);
111	db_putnchars(BACKUP, db_le - db_lc);
112	db_le -= n;
113}
114
115/* returns TRUE at end-of-line */
116static int
117db_inputchar(c)
118	int	c;
119{
120	static int escstate;
121
122	if (escstate == 1) {
123		/* ESC seen, look for [ or O */
124		if (c == '[' || c == 'O')
125			escstate++;
126		else
127			escstate = 0; /* re-init state machine */
128		return (0);
129	} else if (escstate == 2) {
130		escstate = 0;
131		/*
132		 * If a valid cursor key has been found, translate
133		 * into an emacs-style control key, and fall through.
134		 * Otherwise, drop off.
135		 */
136		switch (c) {
137		case 'A':	/* up */
138			c = CTRL('p');
139			break;
140		case 'B':	/* down */
141			c = CTRL('n');
142			break;
143		case 'C':	/* right */
144			c = CTRL('f');
145			break;
146		case 'D':	/* left */
147			c = CTRL('b');
148			break;
149		default:
150			return (0);
151		}
152	}
153
154	switch (c) {
155	    case CTRL('['):
156		escstate = 1;
157		break;
158	    case CTRL('b'):
159		/* back up one character */
160		if (db_lc > db_lbuf_start) {
161		    cnputc(BACKUP);
162		    db_lc--;
163		}
164		break;
165	    case CTRL('f'):
166		/* forward one character */
167		if (db_lc < db_le) {
168		    cnputc(*db_lc);
169		    db_lc++;
170		}
171		break;
172	    case CTRL('a'):
173		/* beginning of line */
174		while (db_lc > db_lbuf_start) {
175		    cnputc(BACKUP);
176		    db_lc--;
177		}
178		break;
179	    case CTRL('e'):
180		/* end of line */
181		while (db_lc < db_le) {
182		    cnputc(*db_lc);
183		    db_lc++;
184		}
185		break;
186	    case CTRL('h'):
187	    case 0177:
188		/* erase previous character */
189		if (db_lc > db_lbuf_start)
190		    db_delete(1, DEL_BWD);
191		break;
192	    case CTRL('d'):
193		/* erase next character */
194		if (db_lc < db_le)
195		    db_delete(1, DEL_FWD);
196		break;
197	    case CTRL('u'):
198		/* kill entire line: */
199		/* at first, delete to beginning of line */
200		if (db_lc > db_lbuf_start)
201		    db_delete(db_lc - db_lbuf_start, DEL_BWD);
202		/* FALLTHROUGH */
203	    case CTRL('k'):
204		/* delete to end of line */
205		if (db_lc < db_le)
206		    db_delete(db_le - db_lc, DEL_FWD);
207		break;
208	    case CTRL('t'):
209		/* twiddle last 2 characters */
210		if (db_lc >= db_lbuf_start + 2) {
211		    c = db_lc[-2];
212		    db_lc[-2] = db_lc[-1];
213		    db_lc[-1] = c;
214		    cnputc(BACKUP);
215		    cnputc(BACKUP);
216		    cnputc(db_lc[-2]);
217		    cnputc(db_lc[-1]);
218		}
219		break;
220	    case CTRL('r'):
221		db_putstring("^R\n", 3);
222	    redraw:
223		if (db_le > db_lbuf_start) {
224		    db_putstring(db_lbuf_start, db_le - db_lbuf_start);
225		    db_putnchars(BACKUP, db_le - db_lc);
226		}
227		break;
228	    case CTRL('p'):
229		/* Make previous history line the active one. */
230		if (db_lhistcur >= 0) {
231		    bcopy(db_lhistory + db_lhistcur * db_lhistlsize,
232			  db_lbuf_start, db_lhistlsize);
233		    db_lhistcur--;
234		    goto hist_redraw;
235		}
236		break;
237	    case CTRL('n'):
238		/* Make next history line the active one. */
239		if (db_lhistcur < db_lhistidx - 1) {
240		    db_lhistcur += 2;
241		    bcopy(db_lhistory + db_lhistcur * db_lhistlsize,
242			  db_lbuf_start, db_lhistlsize);
243		} else {
244		    /*
245		     * ^N through tail of history, reset the
246		     * buffer to zero length.
247		     */
248		    *db_lbuf_start = '\0';
249		    db_lhistcur = db_lhistidx;
250		}
251
252	    hist_redraw:
253		db_putnchars(BACKUP, db_lc - db_lbuf_start);
254		db_putnchars(BLANK, db_le - db_lbuf_start);
255		db_putnchars(BACKUP, db_le - db_lbuf_start);
256		db_le = strchr(db_lbuf_start, '\0');
257		if (db_le[-1] == '\r' || db_le[-1] == '\n')
258		    *--db_le = '\0';
259		db_lc = db_le;
260		goto redraw;
261
262	    case -1:
263		/*
264		 * eek! the console returned eof.
265		 * probably that means we HAVE no console.. we should try bail
266		 * XXX
267		 */
268		c = '\r';
269	    case '\n':
270		/* FALLTHROUGH */
271	    case '\r':
272		*db_le++ = c;
273		return (1);
274	    default:
275		if (db_le == db_lbuf_end) {
276		    cnputc('\007');
277		}
278		else if (c >= ' ' && c <= '~') {
279		    register char *p;
280
281		    for (p = db_le; p > db_lc; p--)
282			*p = *(p-1);
283		    *db_lc++ = c;
284		    db_le++;
285		    cnputc(c);
286		    db_putstring(db_lc, db_le - db_lc);
287		    db_putnchars(BACKUP, db_le - db_lc);
288		}
289		break;
290	}
291	return (0);
292}
293
294static int
295cnmaygetc()
296{
297	return (-1);
298}
299
300int
301db_readline(lstart, lsize)
302	char *	lstart;
303	int	lsize;
304{
305
306	if (lsize < 2)
307		return (0);
308	if (lsize != db_lhistlsize) {
309		/*
310		 * (Re)initialize input line history.  Throw away any
311		 * existing history.
312		 */
313		db_lhist_nlines = sizeof(db_lhistory) / lsize;
314		db_lhistlsize = lsize;
315		db_lhistidx = -1;
316	}
317	db_lhistcur = db_lhistidx;
318
319	db_force_whitespace();	/* synch output position */
320
321	db_lbuf_start = lstart;
322	db_lbuf_end   = lstart + lsize - 2;	/* Will append NL and NUL. */
323	db_lc = lstart;
324	db_le = lstart;
325
326	while (!db_inputchar(cngetc()))
327	    continue;
328
329	db_capture_write(lstart, db_le - db_lbuf_start);
330	db_printf("\n");	/* synch output position */
331	*db_le = 0;
332
333	if (db_le - db_lbuf_start > 1) {
334	    /* Maintain input line history for non-empty lines. */
335	    if (++db_lhistidx == db_lhist_nlines) {
336		/* Rotate history. */
337		bcopy(db_lhistory + db_lhistlsize, db_lhistory,
338		      db_lhistlsize * (db_lhist_nlines - 1));
339		db_lhistidx--;
340	    }
341	    bcopy(lstart, db_lhistory + db_lhistidx * db_lhistlsize,
342		  db_lhistlsize);
343	}
344
345	return (db_le - db_lbuf_start);
346}
347
348void
349db_check_interrupt(void)
350{
351	register int	c;
352
353	c = cnmaygetc();
354	switch (c) {
355	    case -1:		/* no character */
356		return;
357
358	    case CTRL('c'):
359		db_error((char *)0);
360		/*NOTREACHED*/
361
362	    case CTRL('s'):
363		do {
364		    c = cnmaygetc();
365		    if (c == CTRL('c'))
366			db_error((char *)0);
367		} while (c != CTRL('q'));
368		break;
369
370	    default:
371		/* drop on floor */
372		break;
373	}
374}
375