xref: /freebsd/contrib/less/prompt.c (revision c77c488926555ca344ae3a417544cf7a720e1de1)
1 /*
2  * Copyright (C) 1984-2024  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, see the README file.
8  */
9 
10 
11 /*
12  * Prompting and other messages.
13  * There are three flavors of prompts, SHORT, MEDIUM and LONG,
14  * selected by the -m/-M options.
15  * There is also the "equals message", printed by the = command.
16  * A prompt is a message composed of various pieces, such as the
17  * name of the file being viewed, the percentage into the file, etc.
18  */
19 
20 #include "less.h"
21 #include "position.h"
22 
23 extern int pr_type;
24 extern lbool new_file;
25 extern int linenums;
26 extern int hshift;
27 extern int sc_height;
28 extern int jump_sline;
29 extern int less_is_more;
30 extern int header_lines;
31 extern int utf_mode;
32 extern IFILE curr_ifile;
33 #if OSC8_LINK
34 extern char *osc8_path;
35 #endif
36 #if EDITOR
37 extern constant char *editor;
38 extern constant char *editproto;
39 #endif
40 
41 /*
42  * Prototypes for the three flavors of prompts.
43  * These strings are expanded by pr_expand().
44  */
45 static constant char s_proto[] =
46   "?n?f%f .?m(%T %i of %m) ..?e(END) ?x- Next\\: %x..%t";
47 static constant char m_proto[] =
48   "?n?f%f .?m(%T %i of %m) ..?e(END) ?x- Next\\: %x.:?pB%pB\\%:byte %bB?s/%s...%t";
49 static constant char M_proto[] =
50   "?f%f .?n?m(%T %i of %m) ..?ltlines %lt-%lb?L/%L. :byte %bB?s/%s. .?e(END) ?x- Next\\: %x.:?pB%pB\\%..%t";
51 static constant char e_proto[] =
52   "?f%f .?m(%T %i of %m) .?ltlines %lt-%lb?L/%L. .byte %bB?s/%s. ?e(END) :?pB%pB\\%..%t";
53 static constant char h_proto[] =
54   "HELP -- ?eEND -- Press g to see it again:Press RETURN for more., or q when done";
55 static constant char w_proto[] =
56   "Waiting for data";
57 static constant char more_proto[] =
58   "--More--(?eEND ?x- Next\\: %x.:?pB%pB\\%:byte %bB?s/%s...%t)";
59 
60 public char *prproto[3];
61 public char constant *eqproto = e_proto;
62 public char constant *hproto = h_proto;
63 public char constant *wproto = w_proto;
64 
65 static char message[PROMPT_SIZE];
66 static char *mp;
67 
68 /*
69  * Initialize the prompt prototype strings.
70  */
71 public void init_prompt(void)
72 {
73 	prproto[0] = save(s_proto);
74 	prproto[1] = save(less_is_more ? more_proto : m_proto);
75 	prproto[2] = save(M_proto);
76 	eqproto = save(e_proto);
77 	hproto = save(h_proto);
78 	wproto = save(w_proto);
79 }
80 
81 /*
82  * Append a string to the end of the message.
83  * nprt means the character *may* be nonprintable
84  * and should be converted to printable form.
85  */
86 static void ap_estr(constant char *s, lbool nprt)
87 {
88 	constant char *es = s + strlen(s);
89 	while (*s != '\0')
90 	{
91 		LWCHAR ch = step_charc(&s, +1, es);
92 		constant char *ps;
93 		char ubuf[MAX_UTF_CHAR_LEN+1];
94 		size_t plen;
95 
96 		if (nprt)
97 		{
98 			ps = utf_mode ? prutfchar(ch) : prchar(ch);
99 		} else
100 		{
101 			char *up = ubuf;
102 			put_wchar(&up, ch);
103 			*up = '\0';
104 			ps = ubuf;
105 		}
106 		plen = strlen(ps);
107 		if (mp + plen >= message + PROMPT_SIZE)
108 			break;
109 		strcpy(mp, ps);
110 		mp += plen;
111 	}
112 	*mp = '\0';
113 }
114 
115 static void ap_str(constant char *s)
116 {
117 	ap_estr(s, FALSE);
118 }
119 
120 /*
121  * Append a character to the end of the message.
122  */
123 static void ap_char(char c)
124 {
125 	if (mp + 1 >= message + PROMPT_SIZE)
126 		return;
127 	*mp++ = c;
128 	*mp = '\0';
129 }
130 
131 /*
132  * Append a POSITION (as a decimal integer) to the end of the message.
133  */
134 static void ap_pos(POSITION pos)
135 {
136 	char buf[INT_STRLEN_BOUND(pos) + 2];
137 
138 	postoa(pos, buf, 10);
139 	ap_str(buf);
140 }
141 
142 /*
143  * Append a line number to the end of the message.
144  */
145 static void ap_linenum(LINENUM linenum)
146 {
147 	char buf[INT_STRLEN_BOUND(linenum) + 2];
148 
149 	linenumtoa(linenum, buf, 10);
150 	ap_str(buf);
151 }
152 
153 /*
154  * Append an integer to the end of the message.
155  */
156 static void ap_int(int num)
157 {
158 	char buf[INT_STRLEN_BOUND(num) + 2];
159 
160 	inttoa(num, buf, 10);
161 	ap_str(buf);
162 }
163 
164 /*
165  * Append a question mark to the end of the message.
166  */
167 static void ap_quest(void)
168 {
169 	ap_str("?");
170 }
171 
172 /*
173  * Return the "current" byte offset in the file.
174  */
175 static POSITION curr_byte(int where)
176 {
177 	POSITION pos;
178 
179 	pos = position(where);
180 	while (pos == NULL_POSITION && where >= 0 && where < sc_height-1)
181 		pos = position(++where);
182 	if (pos == NULL_POSITION)
183 		pos = ch_length();
184 	return (pos);
185 }
186 
187 /*
188  * Return the value of a prototype conditional.
189  * A prototype string may include conditionals which consist of a
190  * question mark followed by a single letter.
191  * Here we decode that letter and return the appropriate boolean value.
192  */
193 static lbool cond(char c, int where)
194 {
195 	POSITION len;
196 
197 	switch (c)
198 	{
199 	case 'a': /* Anything in the message yet? */
200 		return (mp > message);
201 	case 'b': /* Current byte offset known? */
202 		return (curr_byte(where) != NULL_POSITION);
203 	case 'c':
204 		return (hshift != 0);
205 	case 'e': /* At end of file? */
206 		return (eof_displayed());
207 	case 'f': /* Filename known? */
208 	case 'g':
209 		return (strcmp(get_filename(curr_ifile), "-") != 0);
210 	case 'l': /* Line number known? */
211 	case 'd': /* Same as l */
212 		if (!linenums)
213 			return FALSE;
214 		return (currline(where) != 0);
215 	case 'L': /* Final line number known? */
216 	case 'D': /* Final page number known? */
217 		return (linenums && ch_length() != NULL_POSITION);
218 	case 'm': /* More than one file? */
219 #if TAGS
220 		return (ntags() ? (ntags() > 1) : (nifile() > 1));
221 #else
222 		return (nifile() > 1);
223 #endif
224 	case 'n': /* First prompt in a new file? */
225 #if TAGS
226 		return (ntags() ? TRUE : new_file ? TRUE : FALSE);
227 #else
228 		return (new_file ? TRUE : FALSE);
229 #endif
230 	case 'p': /* Percent into file (bytes) known? */
231 		return (curr_byte(where) != NULL_POSITION && ch_length() > 0);
232 	case 'P': /* Percent into file (lines) known? */
233 		return (currline(where) != 0 &&
234 				(len = ch_length()) > 0 &&
235 				find_linenum(len) != 0);
236 	case 's': /* Size of file known? */
237 	case 'B':
238 		return (ch_length() != NULL_POSITION);
239 	case 'x': /* Is there a "next" file? */
240 #if TAGS
241 		if (ntags())
242 			return (FALSE);
243 #endif
244 		return (next_ifile(curr_ifile) != NULL_IFILE);
245 	}
246 	return (FALSE);
247 }
248 
249 /*
250  * Decode a "percent" prototype character.
251  * A prototype string may include various "percent" escapes;
252  * that is, a percent sign followed by a single letter.
253  * Here we decode that letter and take the appropriate action,
254  * usually by appending something to the message being built.
255  */
256 static void protochar(char c, int where)
257 {
258 	POSITION pos;
259 	POSITION len;
260 	int n;
261 	LINENUM linenum;
262 	LINENUM last_linenum;
263 	IFILE h;
264 	char *s;
265 
266 #undef  PAGE_NUM
267 #define PAGE_NUM(linenum)  ((((linenum) - 1) / (sc_height - header_lines - 1)) + 1)
268 
269 	switch (c)
270 	{
271 	case 'b': /* Current byte offset */
272 		pos = curr_byte(where);
273 		if (pos != NULL_POSITION)
274 			ap_pos(pos);
275 		else
276 			ap_quest();
277 		break;
278 	case 'c':
279 		ap_int(hshift);
280 		break;
281 	case 'd': /* Current page number */
282 		linenum = currline(where);
283 		if (linenum > 0 && sc_height > header_lines + 1)
284 			ap_linenum(PAGE_NUM(linenum));
285 		else
286 			ap_quest();
287 		break;
288 	case 'D': /* Final page number */
289 		/* Find the page number of the last byte in the file (len-1). */
290 		len = ch_length();
291 		if (len == NULL_POSITION)
292 			ap_quest();
293 		else if (len == 0)
294 			/* An empty file has no pages. */
295 			ap_linenum(0);
296 		else
297 		{
298 			linenum = find_linenum(len - 1);
299 			if (linenum <= 0)
300 				ap_quest();
301 			else
302 				ap_linenum(PAGE_NUM(linenum));
303 		}
304 		break;
305 #if EDITOR
306 	case 'E': /* Editor name */
307 		ap_str(editor);
308 		break;
309 #endif
310 	case 'f': /* File name */
311 		ap_estr(get_filename(curr_ifile), TRUE);
312 		break;
313 	case 'F': /* Last component of file name */
314 		ap_estr(last_component(get_filename(curr_ifile)), TRUE);
315 		break;
316 	case 'g': /* Shell-escaped file name */
317 		s = shell_quote(get_filename(curr_ifile));
318 		ap_str(s);
319 		free(s);
320 		break;
321 	case 'i': /* Index into list of files */
322 #if TAGS
323 		if (ntags())
324 			ap_int(curr_tag());
325 		else
326 #endif
327 			ap_int(get_index(curr_ifile));
328 		break;
329 	case 'l': /* Current line number */
330 		linenum = currline(where);
331 		if (linenum != 0)
332 			ap_linenum(vlinenum(linenum));
333 		else
334 			ap_quest();
335 		break;
336 	case 'L': /* Final line number */
337 		len = ch_length();
338 		if (len == NULL_POSITION || len == ch_zero() ||
339 		    (linenum = find_linenum(len)) <= 0)
340 			ap_quest();
341 		else
342 			ap_linenum(vlinenum(linenum-1));
343 		break;
344 	case 'm': /* Number of files */
345 #if TAGS
346 		n = ntags();
347 		if (n)
348 			ap_int(n);
349 		else
350 #endif
351 			ap_int(nifile());
352 		break;
353 	case 'o': /* path (URI without protocol) of selected OSC8 link */
354 #if OSC8_LINK
355 		if (osc8_path != NULL)
356 			ap_str(osc8_path);
357 		else
358 #endif
359 			ap_quest();
360 		break;
361 	case 'p': /* Percent into file (bytes) */
362 		pos = curr_byte(where);
363 		len = ch_length();
364 		if (pos != NULL_POSITION && len > 0)
365 			ap_int(percentage(pos,len));
366 		else
367 			ap_quest();
368 		break;
369 	case 'P': /* Percent into file (lines) */
370 		linenum = currline(where);
371 		if (linenum == 0 ||
372 		    (len = ch_length()) == NULL_POSITION || len == ch_zero() ||
373 		    (last_linenum = find_linenum(len)) <= 0)
374 			ap_quest();
375 		else
376 			ap_int(percentage(linenum, last_linenum));
377 		break;
378 	case 's': /* Size of file */
379 	case 'B':
380 		len = ch_length();
381 		if (len != NULL_POSITION)
382 			ap_pos(len);
383 		else
384 			ap_quest();
385 		break;
386 	case 't': /* Truncate trailing spaces in the message */
387 		while (mp > message && mp[-1] == ' ')
388 			mp--;
389 		*mp = '\0';
390 		break;
391 	case 'T': /* Type of list */
392 #if TAGS
393 		if (ntags())
394 			ap_str("tag");
395 		else
396 #endif
397 			ap_str("file");
398 		break;
399 	case 'x': /* Name of next file */
400 		h = next_ifile(curr_ifile);
401 		if (h != NULL_IFILE)
402 			ap_str(get_filename(h));
403 		else
404 			ap_quest();
405 		break;
406 	}
407 }
408 
409 /*
410  * Skip a false conditional.
411  * When a false condition is found (either a false IF or the ELSE part
412  * of a true IF), this routine scans the prototype string to decide
413  * where to resume parsing the string.
414  * We must keep track of nested IFs and skip them properly.
415  */
416 static constant char * skipcond(constant char *p)
417 {
418 	int iflevel;
419 
420 	/*
421 	 * We came in here after processing a ? or :,
422 	 * so we start nested one level deep.
423 	 */
424 	iflevel = 1;
425 
426 	for (;;) switch (*++p)
427 	{
428 	case '?':
429 		/*
430 		 * Start of a nested IF.
431 		 */
432 		iflevel++;
433 		break;
434 	case ':':
435 		/*
436 		 * Else.
437 		 * If this matches the IF we came in here with,
438 		 * then we're done.
439 		 */
440 		if (iflevel == 1)
441 			return (p);
442 		break;
443 	case '.':
444 		/*
445 		 * Endif.
446 		 * If this matches the IF we came in here with,
447 		 * then we're done.
448 		 */
449 		if (--iflevel == 0)
450 			return (p);
451 		break;
452 	case '\\':
453 		/*
454 		 * Backslash escapes the next character.
455 		 */
456 		if (p[1] != '\0')
457 			++p;
458 		break;
459 	case '\0':
460 		/*
461 		 * Whoops.  Hit end of string.
462 		 * This is a malformed conditional, but just treat it
463 		 * as if all active conditionals ends here.
464 		 */
465 		return (p-1);
466 	}
467 	/*NOTREACHED*/
468 }
469 
470 /*
471  * Decode a char that represents a position on the screen.
472  */
473 static constant char * wherechar(char constant *p, int *wp)
474 {
475 	switch (*p)
476 	{
477 	case 'b': case 'd': case 'l': case 'p': case 'P':
478 		switch (*++p)
479 		{
480 		case 't':   *wp = TOP;                  break;
481 		case 'm':   *wp = MIDDLE;               break;
482 		case 'b':   *wp = BOTTOM;               break;
483 		case 'B':   *wp = BOTTOM_PLUS_ONE;      break;
484 		case 'j':   *wp = sindex_from_sline(jump_sline); break;
485 		default:    *wp = TOP;  p--;            break;
486 		}
487 	}
488 	return (p);
489 }
490 
491 /*
492  * Construct a message based on a prototype string.
493  */
494 public constant char * pr_expand(constant char *proto)
495 {
496 	constant char *p;
497 	char c;
498 	int where;
499 
500 	mp = message;
501 
502 	if (*proto == '\0')
503 		return ("");
504 
505 	for (p = proto;  *p != '\0';  p++)
506 	{
507 		switch (*p)
508 		{
509 		default: /* Just put the character in the message */
510 			ap_char(*p);
511 			break;
512 		case '\\': /* Backslash escapes the next character */
513 			if (p[1] != '\0')
514 				ap_char(*++p);
515 			break;
516 		case '?': /* Conditional (IF) */
517 			if ((c = *++p) == '\0')
518 				--p;
519 			else
520 			{
521 				where = 0;
522 				p = wherechar(p, &where);
523 				if (!cond(c, where))
524 					p = skipcond(p);
525 			}
526 			break;
527 		case ':': /* ELSE */
528 			p = skipcond(p);
529 			break;
530 		case '.': /* ENDIF */
531 			break;
532 		case '%': /* Percent escape */
533 			if ((c = *++p) == '\0')
534 				--p;
535 			else
536 			{
537 				where = 0;
538 				p = wherechar(p, &where);
539 				protochar(c, where);
540 			}
541 			break;
542 		}
543 	}
544 
545 	if (mp == message)
546 		return ("");
547 	return (message);
548 }
549 
550 /*
551  * Return a message suitable for printing by the "=" command.
552  */
553 public constant char * eq_message(void)
554 {
555 	return (pr_expand(eqproto));
556 }
557 
558 /*
559  * Return a prompt.
560  * This depends on the prompt type (SHORT, MEDIUM, LONG), etc.
561  * If we can't come up with an appropriate prompt, return NULL
562  * and the caller will prompt with a colon.
563  */
564 public constant char * pr_string(void)
565 {
566 	constant char *prompt;
567 	int type;
568 
569 	type = (!less_is_more) ? pr_type : pr_type ? 0 : 1;
570 	prompt = pr_expand((ch_getflags() & CH_HELPFILE) ?
571 				hproto : prproto[type]);
572 	new_file = FALSE;
573 	return (prompt);
574 }
575 
576 /*
577  * Return a message suitable for printing while waiting in the F command.
578  */
579 public constant char * wait_message(void)
580 {
581 	return (pr_expand(wproto));
582 }
583