1 /*
2 * Copyright (C) 1984-2025 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_width;
28 extern int sc_height;
29 extern int jump_sline;
30 extern int less_is_more;
31 extern int header_lines;
32 extern int utf_mode;
33 extern IFILE curr_ifile;
34 #if OSC8_LINK
35 extern char *osc8_path;
36 #endif
37 #if EDITOR
38 extern constant char *editor;
39 extern constant char *editproto;
40 #endif
41
42 /*
43 * Prototypes for the three flavors of prompts.
44 * These strings are expanded by pr_expand().
45 */
46 static constant char s_proto[] =
47 "?n?f%f .?m(%T %i of %m) ..?e(END) ?x- Next\\: %x..%t";
48 static constant char m_proto[] =
49 "?n?f%f .?m(%T %i of %m) ..?e(END) ?x- Next\\: %x.:?pB%pB\\%:byte %bB?s/%s...%t";
50 static constant char M_proto[] =
51 "?f%f .?n?m(%T %i of %m) ..?ltlines %lt-%lb?L/%L. :byte %bB?s/%s. .?e(END) ?x- Next\\: %x.:?pB%pB\\%..?c (column %c).%t";
52 static constant char e_proto[] =
53 "?f%f .?m(%T %i of %m) .?ltlines %lt-%lb?L/%L. .byte %bB?s/%s. ?e(END) :?pB%pB\\%..?c (column %c).%t";
54 static constant char h_proto[] =
55 "HELP -- ?eEND -- Press g to see it again:Press RETURN for more., or q when done";
56 static constant char w_proto[] =
57 "Waiting for data";
58 static constant char more_proto[] =
59 "--More--(?eEND ?x- Next\\: %x.:?pB%pB\\%:byte %bB?s/%s...%t)";
60
61 public char *prproto[3];
62 public char constant *eqproto = e_proto;
63 public char constant *hproto = h_proto;
64 public char constant *wproto = w_proto;
65
66 static char message[PROMPT_SIZE];
67 static char *mp;
68 static int longest_line;
69
70 /*
71 * Initialize the prompt prototype strings.
72 */
init_prompt(void)73 public void init_prompt(void)
74 {
75 prproto[0] = save(s_proto);
76 prproto[1] = save(less_is_more ? more_proto : m_proto);
77 prproto[2] = save(M_proto);
78 eqproto = save(e_proto);
79 hproto = save(h_proto);
80 wproto = save(w_proto);
81 }
82
83 /*
84 * Get width of longest line currently on screen.
85 * Calling longest_line_width() is expensive, so we cache its value here
86 * in case it is called more than once per prompt expansion.
87 */
pr_longest_line(void)88 static int pr_longest_line(void)
89 {
90 if (longest_line < 0)
91 longest_line = longest_line_width();
92 return longest_line;
93 }
94
95 /*
96 * Append a string to the end of the message.
97 * nprt means the character *may* be nonprintable
98 * and should be converted to printable form.
99 */
ap_estr(constant char * s,lbool nprt)100 static void ap_estr(constant char *s, lbool nprt)
101 {
102 constant char *es = s + strlen(s);
103 while (*s != '\0')
104 {
105 LWCHAR ch = step_charc(&s, +1, es);
106 constant char *ps;
107 char ubuf[MAX_UTF_CHAR_LEN+1];
108 size_t plen;
109
110 if (nprt)
111 {
112 ps = utf_mode ? prutfchar(ch) : prchar(ch);
113 } else
114 {
115 char *up = ubuf;
116 put_wchar(&up, ch);
117 *up = '\0';
118 ps = ubuf;
119 }
120 plen = strlen(ps);
121 if (mp + plen >= message + PROMPT_SIZE)
122 break;
123 strcpy(mp, ps);
124 mp += plen;
125 }
126 *mp = '\0';
127 }
128
ap_str(constant char * s)129 static void ap_str(constant char *s)
130 {
131 ap_estr(s, FALSE);
132 }
133
134 /*
135 * Append a character to the end of the message.
136 */
ap_char(char c)137 static void ap_char(char c)
138 {
139 if (mp + 1 >= message + PROMPT_SIZE)
140 return;
141 *mp++ = c;
142 *mp = '\0';
143 }
144
145 /*
146 * Append a POSITION (as a decimal integer) to the end of the message.
147 */
ap_pos(POSITION pos)148 static void ap_pos(POSITION pos)
149 {
150 char buf[INT_STRLEN_BOUND(pos) + 2];
151
152 postoa(pos, buf, 10);
153 ap_str(buf);
154 }
155
156 /*
157 * Append a line number to the end of the message.
158 */
ap_linenum(LINENUM linenum)159 static void ap_linenum(LINENUM linenum)
160 {
161 char buf[INT_STRLEN_BOUND(linenum) + 2];
162
163 linenumtoa(linenum, buf, 10);
164 ap_str(buf);
165 }
166
167 /*
168 * Append an integer to the end of the message.
169 */
ap_int(int num)170 static void ap_int(int num)
171 {
172 char buf[INT_STRLEN_BOUND(num) + 2];
173
174 inttoa(num, buf, 10);
175 ap_str(buf);
176 }
177
178 /*
179 * Append a question mark to the end of the message.
180 */
ap_quest(void)181 static void ap_quest(void)
182 {
183 ap_str("?");
184 }
185
186 /*
187 * Return the "current" byte offset in the file.
188 */
curr_byte(int where)189 static POSITION curr_byte(int where)
190 {
191 POSITION pos;
192
193 pos = position(where);
194 while (pos == NULL_POSITION && where >= 0 && where < sc_height-1)
195 pos = position(++where);
196 if (pos == NULL_POSITION)
197 pos = ch_length();
198 return (pos);
199 }
200
201 /*
202 * Return the value of a prototype conditional.
203 * A prototype string may include conditionals which consist of a
204 * question mark followed by a single letter.
205 * Here we decode that letter and return the appropriate boolean value.
206 */
cond(char c,int where)207 static lbool cond(char c, int where)
208 {
209 POSITION len;
210
211 switch (c)
212 {
213 case 'a': /* Anything in the message yet? */
214 return (mp > message);
215 case 'b': /* Current byte offset known? */
216 return (curr_byte(where) != NULL_POSITION);
217 case 'c':
218 return (hshift != 0);
219 case 'e': /* At end of file? */
220 return (eof_displayed(FALSE));
221 case 'f': /* Filename known? */
222 case 'g':
223 return (strcmp(get_filename(curr_ifile), "-") != 0);
224 case 'l': /* Line number known? */
225 case 'd': /* Same as l */
226 if (!linenums)
227 return FALSE;
228 return (currline(where) != 0);
229 case 'L': /* Final line number known? */
230 case 'D': /* Final page number known? */
231 return (linenums && ch_length() != NULL_POSITION);
232 case 'm': /* More than one file? */
233 #if TAGS
234 return (ntags() ? (ntags() > 1) : (nifile() > 1));
235 #else
236 return (nifile() > 1);
237 #endif
238 case 'n': /* First prompt in a new file? */
239 #if TAGS
240 return (ntags() ? TRUE : new_file ? TRUE : FALSE);
241 #else
242 return (new_file ? TRUE : FALSE);
243 #endif
244 case 'p': /* Percent into file (bytes) known? */
245 return (curr_byte(where) != NULL_POSITION && ch_length() > 0);
246 case 'P': /* Percent into file (lines) known? */
247 return (currline(where) != 0 &&
248 (len = ch_length()) > 0 &&
249 find_linenum(len) != 0);
250 case 'Q': /* Any on-screen line truncated? */
251 return (hshift + sc_width < pr_longest_line());
252 case 's': /* Size of file known? */
253 case 'B':
254 return (ch_length() != NULL_POSITION);
255 case 'x': /* Is there a "next" file? */
256 #if TAGS
257 if (ntags())
258 return (FALSE);
259 #endif
260 return (next_ifile(curr_ifile) != NULL_IFILE);
261 }
262 return (FALSE);
263 }
264
265 /*
266 * Decode a "percent" prototype character.
267 * A prototype string may include various "percent" escapes;
268 * that is, a percent sign followed by a single letter.
269 * Here we decode that letter and take the appropriate action,
270 * usually by appending something to the message being built.
271 */
protochar(char c,int where)272 static void protochar(char c, int where)
273 {
274 POSITION pos;
275 POSITION len;
276 LINENUM linenum;
277 LINENUM last_linenum;
278 IFILE h;
279 char *s;
280
281 #undef PAGE_NUM
282 #define PAGE_NUM(linenum) ((((linenum) - 1) / (sc_height - header_lines - 1)) + 1)
283
284 switch (c)
285 {
286 case 'b': /* Current byte offset */
287 pos = curr_byte(where);
288 if (pos != NULL_POSITION)
289 ap_pos(pos);
290 else
291 ap_quest();
292 break;
293 case 'c':
294 ap_int(hshift+1);
295 break;
296 case 'C':
297 ap_int(hshift + sc_width);
298 break;
299 case 'd': /* Current page number */
300 linenum = currline(where);
301 if (linenum > 0 && sc_height > header_lines + 1)
302 ap_linenum(PAGE_NUM(linenum));
303 else
304 ap_quest();
305 break;
306 case 'D': /* Final page number */
307 /* Find the page number of the last byte in the file (len-1). */
308 len = ch_length();
309 if (len == NULL_POSITION)
310 ap_quest();
311 else if (len == 0)
312 /* An empty file has no pages. */
313 ap_linenum(0);
314 else
315 {
316 linenum = find_linenum(len - 1);
317 if (linenum <= 0)
318 ap_quest();
319 else
320 ap_linenum(PAGE_NUM(linenum));
321 }
322 break;
323 #if EDITOR
324 case 'E': /* Editor name */
325 ap_str(editor);
326 break;
327 #endif
328 case 'f': /* File name */
329 ap_estr(get_filename(curr_ifile), TRUE);
330 break;
331 case 'F': /* Last component of file name */
332 ap_estr(last_component(get_filename(curr_ifile)), TRUE);
333 break;
334 case 'g': /* Shell-escaped file name */
335 s = shell_quote(get_filename(curr_ifile));
336 ap_str(s);
337 free(s);
338 break;
339 case 'i': /* Index into list of files */
340 #if TAGS
341 if (ntags())
342 ap_int(curr_tag());
343 else
344 #endif
345 ap_int(get_index(curr_ifile));
346 break;
347 case 'l': /* Current line number */
348 linenum = currline(where);
349 if (linenum != 0)
350 ap_linenum(vlinenum(linenum));
351 else
352 ap_quest();
353 break;
354 case 'L': /* Final line number */
355 len = ch_length();
356 if (len == NULL_POSITION || len == ch_zero() ||
357 (linenum = find_linenum(len)) <= 0)
358 ap_quest();
359 else
360 ap_linenum(vlinenum(linenum-1));
361 break;
362 case 'm': { /* Number of files */
363 #if TAGS
364 int n = ntags();
365 if (n)
366 ap_int(n);
367 else
368 #endif
369 ap_int(nifile());
370 break; }
371 case 'o': /* path (URI without protocol) of selected OSC8 link */
372 #if OSC8_LINK
373 if (osc8_path != NULL)
374 ap_str(osc8_path);
375 else
376 #endif
377 ap_quest();
378 break;
379 case 'p': /* Percent into file (bytes) */
380 pos = curr_byte(where);
381 len = ch_length();
382 if (pos != NULL_POSITION && len > 0)
383 ap_int(percentage(pos,len));
384 else
385 ap_quest();
386 break;
387 case 'P': /* Percent into file (lines) */
388 linenum = currline(where);
389 if (linenum == 0 ||
390 (len = ch_length()) == NULL_POSITION || len == ch_zero() ||
391 (last_linenum = find_linenum(len)) <= 0)
392 ap_quest();
393 else
394 ap_int(percentage(linenum, last_linenum));
395 break;
396 case 'Q': /* Percent shifted horizontally */
397 ap_int(percentage(hshift + sc_width, pr_longest_line()));
398 break;
399 case 's': /* Size of file */
400 case 'B':
401 len = ch_length();
402 if (len != NULL_POSITION)
403 ap_pos(len);
404 else
405 ap_quest();
406 break;
407 case 't': /* Truncate trailing spaces in the message */
408 while (mp > message && mp[-1] == ' ')
409 mp--;
410 *mp = '\0';
411 break;
412 case 'T': /* Type of list */
413 #if TAGS
414 if (ntags())
415 ap_str("tag");
416 else
417 #endif
418 ap_str("file");
419 break;
420 case 'W': /* Width of longest line on screen */
421 ap_int(pr_longest_line());
422 break;
423 case 'x': /* Name of next file */
424 h = next_ifile(curr_ifile);
425 if (h != NULL_IFILE)
426 ap_str(get_filename(h));
427 else
428 ap_quest();
429 break;
430 }
431 }
432
433 /*
434 * Skip a false conditional.
435 * When a false condition is found (either a false IF or the ELSE part
436 * of a true IF), this routine scans the prototype string to decide
437 * where to resume parsing the string.
438 * We must keep track of nested IFs and skip them properly.
439 */
skipcond(constant char * p)440 static constant char * skipcond(constant char *p)
441 {
442 int iflevel;
443
444 /*
445 * We came in here after processing a ? or :,
446 * so we start nested one level deep.
447 */
448 iflevel = 1;
449
450 for (;;) switch (*++p)
451 {
452 case '?':
453 /*
454 * Start of a nested IF.
455 */
456 iflevel++;
457 break;
458 case ':':
459 /*
460 * Else.
461 * If this matches the IF we came in here with,
462 * then we're done.
463 */
464 if (iflevel == 1)
465 return (p);
466 break;
467 case '.':
468 /*
469 * Endif.
470 * If this matches the IF we came in here with,
471 * then we're done.
472 */
473 if (--iflevel == 0)
474 return (p);
475 break;
476 case '\\':
477 /*
478 * Backslash escapes the next character.
479 */
480 if (p[1] != '\0')
481 ++p;
482 break;
483 case '\0':
484 /*
485 * Whoops. Hit end of string.
486 * This is a malformed conditional, but just treat it
487 * as if all active conditionals ends here.
488 */
489 return (p-1);
490 }
491 /*NOTREACHED*/
492 }
493
494 /*
495 * Decode a char that represents a position on the screen.
496 */
wherechar(char constant * p,int * wp)497 static constant char * wherechar(char constant *p, int *wp)
498 {
499 switch (*p)
500 {
501 case 'b': case 'd': case 'l': case 'p': case 'P':
502 switch (*++p)
503 {
504 case 't': *wp = TOP; break;
505 case 'm': *wp = MIDDLE; break;
506 case 'b': *wp = BOTTOM; break;
507 case 'B': *wp = BOTTOM_PLUS_ONE; break;
508 case 'j': *wp = sindex_from_sline(jump_sline); break;
509 default: *wp = TOP; p--; break;
510 }
511 }
512 return (p);
513 }
514
515 /*
516 * Construct a message based on a prototype string.
517 */
pr_expand(constant char * proto)518 public constant char * pr_expand(constant char *proto)
519 {
520 constant char *p;
521 char c;
522 int where;
523
524 if (*proto == '\0')
525 return ("");
526
527 mp = message;
528 longest_line = -1;
529
530 for (p = proto; *p != '\0'; p++)
531 {
532 switch (*p)
533 {
534 default: /* Just put the character in the message */
535 ap_char(*p);
536 break;
537 case '\\': /* Backslash escapes the next character */
538 if (p[1] != '\0')
539 ap_char(*++p);
540 break;
541 case '?': /* Conditional (IF) */
542 if ((c = *++p) == '\0')
543 --p;
544 else
545 {
546 where = 0;
547 p = wherechar(p, &where);
548 if (!cond(c, where))
549 p = skipcond(p);
550 }
551 break;
552 case ':': /* ELSE */
553 p = skipcond(p);
554 break;
555 case '.': /* ENDIF */
556 break;
557 case '%': /* Percent escape */
558 if ((c = *++p) == '\0')
559 --p;
560 else
561 {
562 where = 0;
563 p = wherechar(p, &where);
564 protochar(c, where);
565 }
566 break;
567 }
568 }
569
570 if (mp == message)
571 return ("");
572 return (message);
573 }
574
575 /*
576 * Return a message suitable for printing by the "=" command.
577 */
eq_message(void)578 public constant char * eq_message(void)
579 {
580 return (pr_expand(eqproto));
581 }
582
583 /*
584 * Return a prompt.
585 * This depends on the prompt type (SHORT, MEDIUM, LONG), etc.
586 * If we can't come up with an appropriate prompt, return NULL
587 * and the caller will prompt with a colon.
588 */
pr_string(void)589 public constant char * pr_string(void)
590 {
591 constant char *prompt;
592 int type;
593
594 type = (!less_is_more) ? pr_type : pr_type ? 0 : 1;
595 prompt = pr_expand((ch_getflags() & CH_HELPFILE) ?
596 hproto : prproto[type]);
597 new_file = FALSE;
598 return (prompt);
599 }
600
601 /*
602 * Return a message suitable for printing while waiting in the F command.
603 */
wait_message(void)604 public constant char * wait_message(void)
605 {
606 return (pr_expand(wproto));
607 }
608