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Date:: Wed Mar 10 21:40:20 2021 UTC
Message:: fix out of bound access in the minibuffer code
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1 /*
2  * Copyright (c) 2021 Omar Polo <op@omarpolo.com>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 /*
18  * Ncurses UI for telescope.
19  *
20  *
21  * Text wrapping
22  * =============
23  *
24  * There's a simple text wrapping algorithm.
25  *
26  * 1. if it's a line in a pre-formatted block:
27  *    a. hard wrap.
28  *    b. repeat
29  * 2. there is enough room for the next word?
30  *    a. yes: render it
31  *    b. no: break the current line.
32  *       i.  while there isn't enough space to draw the current
33  *           word, hard-wrap it
34  *       ii. draw the remainder of the current word (can be the
35  *           the entirely)
36  * 3. render the spaces after the word
37  *    a. but if there is not enough room break the line and
38  *       forget them
39  * 4. repeat
40  *
41  *
42  * Text scrolling
43  * ==============
44  *
45  * ncurses allows you to scroll a window, but when a line goes out of
46  * the visible area it's forgotten.  We keep a list of formatted lines
47  * (``visual lines'') that we know fits in the window, and draw them.
48  * This way is easy to scroll: just call wscrl and then render the
49  * first/last line!
50  *
51  * This means that on every resize we have to clear our list of lines
52  * and re-render everything.  A clever approach would be to do this
53  * ``on-demand''.
54  *
55  * TODO: make the text formatting on-demand.
56  *
57  */
58 
59 #include <telescope.h>
60 
61 #include <ctype.h>
62 #include <curses.h>
63 #include <event.h>
64 #include <locale.h>
65 #include <signal.h>
66 #include <stdarg.h>
67 #include <stdlib.h>
68 #include <string.h>
69 #include <unistd.h>
70 
71 #define TAB_CURRENT	0x1
72 
73 #define MIN(a, b) ((a) < (b) ? (a) : (b))
74 #define MAX(a, b) ((a) > (b) ? (a) : (b))
75 
76 struct kmap;
77 
78 static struct event	stdioev, winchev;
79 
80 static int		 kbd(const char*);
81 static void		 kmap_define_key(struct kmap*, const char*, void(*)(struct tab*));
82 static void		 load_default_keys(void);
83 static int		 push_line(struct tab*, const struct line*, const char*, size_t);
84 static void		 empty_vlist(struct tab*);
85 static void		 restore_cursor(struct tab *);
86 
87 static void		 cmd_previous_line(struct tab*);
88 static void		 cmd_next_line(struct tab*);
89 static void		 cmd_forward_char(struct tab*);
90 static void		 cmd_backward_char(struct tab*);
91 static void		 cmd_redraw(struct tab*);
92 static void		 cmd_scroll_line_down(struct tab*);
93 static void		 cmd_scroll_line_up(struct tab*);
94 static void		 cmd_scroll_up(struct tab*);
95 static void		 cmd_scroll_down(struct tab*);
96 static void		 cmd_kill_telescope(struct tab*);
97 static void		 cmd_push_button(struct tab*);
98 static void		 cmd_execute_extended_command(struct tab*);
99 
100 static void		 global_key_unbound(void);
101 
102 static void		 cmd_mini_del(struct tab*);
103 static void		 cmd_mini_forward_char(struct tab*);
104 static void		 cmd_mini_backward_char(struct tab*);
105 static void		 cmd_mini_move_end_of_line(struct tab*);
106 static void		 cmd_mini_move_beginning_of_line(struct tab*);
107 static void		 cmd_mini_kill_line(struct tab*);
108 static void		 cmd_mini_abort();
109 static void		 cmd_mini_complete_and_exit();
110 
111 static void		 eecmd_self_insert(void);
112 static void		 eecmd_select(void);
113 
114 static struct line	*nth_line(struct tab*, size_t);
115 static struct tab	*current_tab(void);
116 static void		 dispatch_stdio(int, short, void*);
117 static void		 handle_clear_minibuf(int, short, void*);
118 static void		 handle_resize(int, short, void*);
119 static int		 word_bourdaries(const char*, const char*, const char**, const char**);
120 static void		 wrap_text(struct tab*, const char*, struct line*);
121 static int		 hardwrap_text(struct tab*, struct line*);
122 static int		 wrap_page(struct tab*);
123 static void		 print_line(struct line*);
124 static void		 redraw_tabline(void);
125 static void		 redraw_modeline(struct tab*);
126 static void		 redraw_minibuffer(void);
127 static void		 redraw_tab(struct tab*);
128 static void		 message(const char*, ...) __attribute__((format(printf, 1, 2)));
129 static void		 start_loading_anim(struct tab*);
130 static void		 update_loading_anim(int, short, void*);
131 static void		 stop_loading_anim(struct tab*);
132 static void		 load_url_in_tab(struct tab*, const char*);
133 static void		 enter_minibuffer(void(*)(void), void(*)(void), void(*)(void));
134 static void		 exit_minibuffer(void);
135 static void		 new_tab(void);
136 
137 static struct { int meta, key; } thiskey;
138 
139 static WINDOW	*tabline, *body, *modeline, *minibuf;
140 static int	 body_lines, body_cols;
141 
142 static struct event	clminibufev;
143 static int		clminibufev_set;
144 static struct timeval	clminibufev_timer = { 5, 0 };
145 static struct timeval	loadingev_timer = { 0, 250000 };
146 
147 static uint32_t		 tab_counter;
148 
149 struct ui_state {
150 	int			curs_x;
151 	int			curs_y;
152 	size_t			line_off;
153 	size_t			line_max;
154 
155 	short			loading_anim;
156 	short			loading_anim_step;
157 	struct event		loadingev;
158 
159 	TAILQ_HEAD(, line)	head;
160 };
161 
162 #define CTRL(n)	((n)&0x1F)
163 
164 struct keytable {
165 	char	*p;
166 	int	 k;
167 } keytable[] = {
168 	{ "<up>",	KEY_UP },
169 	{ "<down>",	KEY_DOWN },
170 	{ "<left>",	KEY_LEFT },
171 	{ "<right>",	KEY_RIGHT },
172 	{ "<prior>",	KEY_PPAGE },
173 	{ "<next>",	KEY_NPAGE },
174 	{ "<home>",	KEY_HOME },
175 	{ "<end>",	KEY_END },
176 	/* ... */
177 	{ "del",	KEY_BACKSPACE },
178 	{ "esc",	27 },
179 	{ "space",	' ' },
180 	{ "spc",	' ' },
181 	{ "enter",	CTRL('m') },
182 	{ "ret",	CTRL('m' )},
183 	{ "tab",	CTRL('i') },
184 	/* ... */
185 	{ NULL, 0 },
186 };
187 
188 struct kmap {
189 	TAILQ_HEAD(map, keymap)	m;
190 	void			(*unhandled_input)(void);
191 };
192 
193 struct kmap global_map,
194 	minibuffer_map,
195 	*current_map,
196 	*base_map;
197 
198 struct keymap {
199 	int			 meta;
200 	int			 key;
201 	struct kmap		 map;
202 	void			(*fn)(struct tab*);
203 
204 	TAILQ_ENTRY(keymap)	 keymaps;
205 };
206 
207 static int	in_minibuffer;
208 
209 static struct {
210 	char	*curmesg;
211 
212 	char	 buf[1025];
213 	size_t	 off, len;
214 	char	 prompt[16];
215 	void	 (*donefn)(void);
216 	void	 (*abortfn)(void);
217 } ministate;
218 
219 static int
220 kbd(const char *key)
221 {
222 	struct keytable *t;
223 
224 	for (t = keytable; t->p != NULL; ++t) {
225 		if (has_prefix(key, t->p))
226 			return t->k;
227 	}
228 
229         return *key;
230 }
231 
232 static const char *
233 unkbd(int k)
234 {
235 	struct keytable *t;
236 
237 	for (t = keytable; t->p != NULL; ++t) {
238 		if (k == t->k)
239 			return t->p;
240 	}
241 
242 	return NULL;
243 }
244 
245 static void
246 kmap_define_key(struct kmap *map, const char *key, void (*fn)(struct tab*))
247 {
248 	int ctrl, meta, k;
249 	struct keymap	*entry;
250 
251 again:
252 	if ((ctrl = has_prefix(key, "C-")))
253 		key += 2;
254 	if ((meta = has_prefix(key, "M-")))
255 		key += 2;
256 	if (*key == '\0')
257 		_exit(1);
258 	k = kbd(key);
259 
260 	if (ctrl)
261 		k = CTRL(k);
262 
263 	/* skip key & spaces */
264 	while (*key != '\0' && !isspace(*key))
265 		++key;
266 	while (*key != '\0' && isspace(*key))
267 		++key;
268 
269 	TAILQ_FOREACH(entry, &map->m, keymaps) {
270 		if (entry->meta == meta && entry->key == k) {
271 			if (*key == '\0') {
272 				entry->fn = fn;
273 				return;
274 			}
275 			map = &entry->map;
276 			goto again;
277 		}
278 	}
279 
280 	if ((entry = calloc(1, sizeof(*entry))) == NULL)
281 		abort();
282 
283 	entry->meta = meta;
284 	entry->key = k;
285 	TAILQ_INIT(&entry->map.m);
286 
287 	if (TAILQ_EMPTY(&map->m))
288 		TAILQ_INSERT_HEAD(&map->m, entry, keymaps);
289 	else
290 		TAILQ_INSERT_TAIL(&map->m, entry, keymaps);
291 
292         if (*key != '\0') {
293 		map = &entry->map;
294 		goto again;
295 	}
296 
297 	entry->fn = fn;
298 }
299 
300 static inline void
301 global_set_key(const char *key, void (*fn)(struct tab*))
302 {
303 	kmap_define_key(&global_map, key, fn);
304 }
305 
306 static inline void
307 minibuffer_set_key(const char *key, void (*fn)(struct tab*))
308 {
309 	kmap_define_key(&minibuffer_map, key, fn);
310 }
311 
312 static void
313 load_default_keys(void)
314 {
315 	/* === global map === */
316 
317 	/* emacs */
318 	global_set_key("C-p",		cmd_previous_line);
319 	global_set_key("C-n",		cmd_next_line);
320 	global_set_key("C-f",		cmd_forward_char);
321 	global_set_key("C-b",		cmd_backward_char);
322 
323 	global_set_key("M-v",		cmd_scroll_up);
324 	global_set_key("C-v",		cmd_scroll_down);
325 
326 	global_set_key("C-x C-c",	cmd_kill_telescope);
327 
328 	global_set_key("M-x",		cmd_execute_extended_command);
329 
330 	/* vi/vi-like */
331 	global_set_key("k",		cmd_previous_line);
332 	global_set_key("j",		cmd_next_line);
333 	global_set_key("l",		cmd_forward_char);
334 	global_set_key("h",		cmd_backward_char);
335 
336 	global_set_key("K",		cmd_scroll_line_up);
337 	global_set_key("J",		cmd_scroll_line_down);
338 
339 	/* tmp */
340 	global_set_key("q",		cmd_kill_telescope);
341 
342 	global_set_key(":",		cmd_execute_extended_command);
343 
344 	/* cua */
345 	global_set_key("<up>",		cmd_previous_line);
346 	global_set_key("<down>",	cmd_next_line);
347 	global_set_key("<right>",	cmd_forward_char);
348 	global_set_key("<left>",	cmd_backward_char);
349 	global_set_key("<prior>",	cmd_scroll_up);
350 	global_set_key("<next>",	cmd_scroll_down);
351 
352 	/* "ncurses standard" */
353 	global_set_key("C-l",		cmd_redraw);
354 
355 	/* global */
356 	global_set_key("C-m",		cmd_push_button);
357 
358 	/* === minibuffer map === */
359 	minibuffer_set_key("ret",		cmd_mini_complete_and_exit);
360 	minibuffer_set_key("C-g",		cmd_mini_abort);
361 	minibuffer_set_key("esc",		cmd_mini_abort);
362 	minibuffer_set_key("del",		cmd_mini_del);
363 
364 	minibuffer_set_key("C-f",		cmd_mini_forward_char);
365 	minibuffer_set_key("C-b",		cmd_mini_backward_char);
366 	minibuffer_set_key("C-e",		cmd_mini_move_end_of_line);
367 	minibuffer_set_key("C-a",		cmd_mini_move_beginning_of_line);
368 	minibuffer_set_key("<end>",		cmd_mini_move_end_of_line);
369 	minibuffer_set_key("<home>",		cmd_mini_move_beginning_of_line);
370 	minibuffer_set_key("C-k",		cmd_mini_kill_line);
371 }
372 
373 static int
374 push_line(struct tab *tab, const struct line *l, const char *buf, size_t len)
375 {
376 	struct line *vl;
377 
378 	tab->s->line_max++;
379 
380 	if ((vl = calloc(1, sizeof(*vl))) == NULL)
381 		return 0;
382 
383 	if (len != 0 && (vl->line = calloc(1, len+1)) == NULL) {
384 		free(vl);
385 		return 0;
386 	}
387 
388 	vl->type = l->type;
389 	if (len != 0)
390 		memcpy(vl->line, buf, len);
391 	vl->alt = l->alt;
392 
393 	if (TAILQ_EMPTY(&tab->s->head))
394 		TAILQ_INSERT_HEAD(&tab->s->head, vl, lines);
395 	else
396 		TAILQ_INSERT_TAIL(&tab->s->head, vl, lines);
397 	return 1;
398 }
399 
400 static void
401 empty_vlist(struct tab *tab)
402 {
403 	struct line *l, *t;
404 
405 	tab->s->line_max = 0;
406 
407 	TAILQ_FOREACH_SAFE(l, &tab->s->head, lines, t) {
408 		TAILQ_REMOVE(&tab->s->head, l, lines);
409 		free(l->line);
410 		/* l->alt references the original line! */
411 		free(l);
412 	}
413 }
414 
415 static void
416 restore_cursor(struct tab *tab)
417 {
418 	wmove(body, tab->s->curs_y, tab->s->curs_x);
419 }
420 
421 static void
422 cmd_previous_line(struct tab *tab)
423 {
424 	if (--tab->s->curs_y < 0) {
425 		tab->s->curs_y = 0;
426 		cmd_scroll_line_up(tab);
427 	}
428 
429 	restore_cursor(tab);
430 }
431 
432 static void
433 cmd_next_line(struct tab *tab)
434 {
435 	if (++tab->s->curs_y > body_lines-1) {
436 		tab->s->curs_y = body_lines-1;
437 		cmd_scroll_line_down(tab);
438 	}
439 
440 	restore_cursor(tab);
441 }
442 
443 static void
444 cmd_forward_char(struct tab *tab)
445 {
446 	tab->s->curs_x = MIN(body_cols-1, tab->s->curs_x+1);
447 	restore_cursor(tab);
448 }
449 
450 static void
451 cmd_backward_char(struct tab *tab)
452 {
453 	tab->s->curs_x = MAX(0, tab->s->curs_x-1);
454 	restore_cursor(tab);
455 }
456 
457 static void
458 cmd_redraw(struct tab *tab)
459 {
460 	handle_resize(0, 0, NULL);
461 }
462 
463 static void
464 cmd_scroll_line_up(struct tab *tab)
465 {
466 	struct line	*l;
467 
468 	if (tab->s->line_off == 0)
469 		return;
470 
471 	l = nth_line(tab, --tab->s->line_off);
472 	wscrl(body, -1);
473 	wmove(body, 0, 0);
474 	print_line(l);
475 }
476 
477 static void
478 cmd_scroll_line_down(struct tab *tab)
479 {
480 	struct line	*l;
481 	size_t		 n;
482 
483 	if (tab->s->line_max == 0 || tab->s->line_off == tab->s->line_max-1)
484 		return;
485 
486 	tab->s->line_off++;
487 	wscrl(body, 1);
488 
489 	if (tab->s->line_max - tab->s->line_off < body_lines)
490 		return;
491 
492 	l = nth_line(tab, tab->s->line_off + body_lines-1);
493 	wmove(body, body_lines-1, 0);
494 	print_line(l);
495 }
496 
497 static void
498 cmd_scroll_up(struct tab *tab)
499 {
500 	size_t off;
501 
502 	off = body_lines+1;
503 
504 	for (; off > 0; --off)
505 		cmd_scroll_line_up(tab);
506 }
507 
508 static void
509 cmd_scroll_down(struct tab *tab)
510 {
511 	ssize_t off;
512 
513 	off = tab->s->line_off + body_lines;
514 	off = MIN(tab->s->line_max, off);
515 
516 	for (; off >= 0; --off)
517 		cmd_scroll_line_down(tab);
518 }
519 
520 static void
521 cmd_kill_telescope(struct tab *tab)
522 {
523 	event_loopbreak();
524 }
525 
526 static void
527 cmd_push_button(struct tab *tab)
528 {
529 	struct line	*l;
530 	size_t		 nth;
531 
532 	nth = tab->s->line_off + tab->s->curs_y;
533 	if (nth > tab->s->line_max)
534 		return;
535 	l = nth_line(tab, nth);
536 	if (l->type != LINE_LINK)
537 		return;
538 
539 	load_url_in_tab(tab, l->alt);
540 }
541 
542 static void
543 cmd_execute_extended_command(struct tab *tab)
544 {
545 	size_t	 len;
546 
547 	enter_minibuffer(eecmd_self_insert, eecmd_select, exit_minibuffer);
548 
549 	len = sizeof(ministate.prompt);
550 	strlcpy(ministate.prompt, "", len);
551 
552 	if (thiskey.meta)
553 		strlcat(ministate.prompt, "M-", len);
554 
555 	strlcat(ministate.prompt, keyname(thiskey.key), len);
556 	strlcat(ministate.prompt, " ", len);
557 }
558 
559 static void
560 global_key_unbound(void)
561 {
562 	const char *keyname;
563 	char tmp[2] = {0, 0};
564 
565 	if ((keyname = unkbd(thiskey.key)) == NULL) {
566 		message("%s%c is undefined",
567 		    thiskey.meta ? "M-" : "",
568 		    thiskey.key);
569 		return;
570 	}
571 
572 	message("%s%s is undefined",
573 	    thiskey.meta ? "M-" : "",
574 	    keyname);
575 }
576 
577 static void
578 cmd_mini_del(struct tab *tab)
579 {
580 	if (ministate.len == 0 || ministate.off == 0)
581 		return;
582 
583 	memmove(&ministate.buf[ministate.off-1],
584 	    &ministate.buf[ministate.off],
585 	    ministate.len - ministate.off + 1);
586 	ministate.off--;
587 	ministate.len--;
588 }
589 
590 static void
591 cmd_mini_forward_char(struct tab *tab)
592 {
593 	if (ministate.off == ministate.len)
594 		return;
595 	ministate.off++;
596 }
597 
598 static void
599 cmd_mini_backward_char(struct tab *tab)
600 {
601 	if (ministate.off == 0)
602 		return;
603 	ministate.off--;
604 }
605 
606 static void
607 cmd_mini_move_end_of_line(struct tab *tab)
608 {
609 	ministate.off = ministate.len;
610 }
611 
612 static void
613 cmd_mini_move_beginning_of_line(struct tab *tab)
614 {
615 	ministate.off = 0;
616 }
617 
618 static void
619 cmd_mini_kill_line(struct tab *tab)
620 {
621         if (ministate.off == ministate.len)
622 		return;
623 	ministate.buf[ministate.off] = '\0';
624 	ministate.len -= ministate.off;
625 }
626 
627 static void
628 cmd_mini_abort(struct tab *tab)
629 {
630         ministate.abortfn();
631 }
632 
633 static void
634 cmd_mini_complete_and_exit(struct tab *tab)
635 {
636 	ministate.donefn();
637 }
638 
639 static void
640 eecmd_self_insert(void)
641 {
642 	if (thiskey.meta || isspace(thiskey.key) ||
643 	    !isgraph(thiskey.key)) {
644 		global_key_unbound();
645 		return;
646 	}
647 
648 	if (ministate.len == sizeof(ministate.buf) -1)
649 		return;
650 
651 	/* TODO: utf8 handling! */
652 
653 	memmove(&ministate.buf[ministate.off+1],
654 	    &ministate.buf[ministate.off],
655 	    ministate.len - ministate.off + 1);
656 	ministate.buf[ministate.off] = thiskey.key;
657 	ministate.off++;
658 	ministate.len++;
659 }
660 
661 static void
662 eecmd_select(void)
663 {
664 	exit_minibuffer();
665 	message("TODO: try to execute %s", ministate.buf);
666 }
667 
668 static struct line *
669 nth_line(struct tab *tab, size_t n)
670 {
671 	struct line	*l;
672 	size_t		 i;
673 
674 	i = 0;
675 	TAILQ_FOREACH(l, &tab->s->head, lines) {
676 		if (i == n)
677 			return l;
678 		i++;
679 	}
680 
681 	/* unreachable */
682 	abort();
683 }
684 
685 static struct tab *
686 current_tab(void)
687 {
688 	struct tab *t;
689 
690 	TAILQ_FOREACH(t, &tabshead, tabs) {
691 		if (t->flags & TAB_CURRENT)
692 			return t;
693 	}
694 
695 	/* unreachable */
696 	abort();
697 }
698 
699 static void
700 dispatch_stdio(int fd, short ev, void *d)
701 {
702 	struct keymap	*k;
703 
704 	thiskey.key = wgetch(body);
705 	if (thiskey.key == ERR)
706 		return;
707 	if (thiskey.key == 27) {
708 		/* TODO: make escape-time customizable */
709 
710 		thiskey.meta = 1;
711 		thiskey.key = wgetch(body);
712 		if (thiskey.key == ERR)
713 			thiskey.key = 27;
714 	} else
715 		thiskey.meta = 0;
716 
717 	TAILQ_FOREACH(k, &current_map->m, keymaps) {
718 		if (k->meta == thiskey.meta &&
719 		    k->key == thiskey.key) {
720 			if (k->fn == NULL)
721 				current_map = &k->map;
722 			else {
723 				current_map = base_map;
724 				k->fn(current_tab());
725 			}
726 			goto done;
727 		}
728 	}
729 
730 	current_map->unhandled_input();
731 	current_map = base_map;
732 
733 done:
734 	redraw_minibuffer();
735 	restore_cursor(current_tab());
736 	wrefresh(tabline);
737 	wrefresh(modeline);
738 
739 	if (in_minibuffer) {
740 		wrefresh(body);
741 		wrefresh(minibuf);
742 	} else {
743 		wrefresh(minibuf);
744 		wrefresh(body);
745 	}
746 }
747 
748 static void
749 handle_clear_minibuf(int fd, short ev, void *d)
750 {
751 	clminibufev_set = 0;
752 
753 	free(ministate.curmesg);
754 	ministate.curmesg = NULL;
755 
756 	redraw_minibuffer();
757 	if (in_minibuffer) {
758 		wrefresh(body);
759 		wrefresh(minibuf);
760 	} else {
761 		wrefresh(minibuf);
762 		wrefresh(body);
763 	}
764 }
765 
766 static void
767 handle_resize(int sig, short ev, void *d)
768 {
769 	struct tab	*tab;
770 
771 	endwin();
772 	refresh();
773 	clear();
774 
775 	/* move and resize the windows, in reverse order! */
776 
777 	mvwin(minibuf, LINES-1, 0);
778 	wresize(minibuf, 1, COLS);
779 
780 	mvwin(modeline, LINES-2, 0);
781 	wresize(modeline, 1, COLS);
782 
783 	wresize(body, LINES-3, COLS);
784 	body_lines = LINES-3;
785 	body_cols = COLS;
786 
787 	wresize(tabline, 1, COLS);
788 
789 	tab = current_tab();
790 
791 	wrap_page(tab);
792 	redraw_tab(tab);
793 }
794 
795 /*
796  * Helper function for wrap_text.  Find the end of the current word
797  * and the end of the separator after the word.
798  */
799 static int
800 word_boundaries(const char *s, const char *sep, const char **endword, const char **endspc)
801 {
802 	*endword = s;
803 	*endword = s;
804 
805 	if (*s == '\0')
806 		return 0;
807 
808 	/* find the end of the current world */
809 	for (; *s != '\0'; ++s) {
810 		if (strchr(sep, *s) != NULL)
811 			break;
812 	}
813 
814 	*endword = s;
815 
816 	/* find the end of the separator */
817 	for (; *s != '\0'; ++s) {
818 		if (strchr(sep, *s) == NULL)
819 			break;
820 	}
821 
822 	*endspc = s;
823 
824 	return 1;
825 }
826 
827 static inline int
828 emitline(struct tab *tab, size_t zero, size_t *off, const struct line *l,
829     const char **line)
830 {
831 	if (!push_line(tab, l, *line, *off - zero))
832 		return 0;
833 	*line += *off - zero;
834 	*off = zero;
835 	return 1;
836 }
837 
838 static inline void
839 emitstr(const char **s, size_t len, size_t *off)
840 {
841 	size_t i;
842 
843 	/* printw("%*s", ...) doesn't seem to respect the precision, so... */
844 	for (i = 0; i < len; ++i)
845 		addch((*s)[i]);
846 	*off += len;
847 	*s += len;
848 }
849 
850 /*
851  * Build a list of visual line by wrapping the given line, assuming
852  * that when printed will have a leading prefix prfx.
853  *
854  * TODO: it considers each byte one cell on the screen!
855  */
856 static void
857 wrap_text(struct tab *tab, const char *prfx, struct line *l)
858 {
859 	size_t		 zero, off, len, split;
860 	const char	*endword, *endspc, *line, *linestart;
861 
862 	zero = strlen(prfx);
863 	off = zero;
864 	line = l->line;
865 	linestart = l->line;
866 
867 	while (word_boundaries(line, " \t-", &endword, &endspc)) {
868 		len = endword - line;
869 		if (off + len >= body_cols) {
870 			emitline(tab, zero, &off, l, &linestart);
871 			while (len >= body_cols) {
872 				/* hard wrap */
873 				emitline(tab, zero, &off, l, &linestart);
874 				len -= body_cols-1;
875 				line += body_cols-1;
876 			}
877 
878 			if (len != 0)
879 				off += len;
880 		} else
881 			off += len;
882 
883 		/* print the spaces iff not at bol */
884 		len = endspc - endword;
885 		/* line = endspc; */
886 		if (off != zero) {
887 			if (off + len >= body_cols) {
888 				emitline(tab, zero, &off, l, &linestart);
889 				linestart = endspc;
890 			} else
891 				off += len;
892 		}
893 
894 		line = endspc;
895 	}
896 
897 	emitline(tab, zero, &off, l, &linestart);
898 }
899 
900 static int
901 hardwrap_text(struct tab *tab, struct line *l)
902 {
903 	size_t		 off, len;
904 	const char	*linestart;
905 
906         len = strlen(l->line);
907 	off = 0;
908 	linestart = l->line;
909 
910 	while (len >= COLS) {
911 		len -= COLS-1;
912 		off = COLS-1;
913 		if (!emitline(tab, 0, &off, l, &linestart))
914 			return 0;
915 	}
916 
917 	if (len != 0)
918 		return emitline(tab, 0, &len, l, &linestart);
919 
920 	return 1;
921 }
922 
923 static int
924 wrap_page(struct tab *tab)
925 {
926 	struct line	*l;
927 
928 	empty_vlist(tab);
929 
930 	TAILQ_FOREACH(l, &tab->page.head, lines) {
931 		switch (l->type) {
932 		case LINE_TEXT:
933 			wrap_text(tab, "", l);
934 			break;
935 		case LINE_LINK:
936 			wrap_text(tab, "=> ", l);
937 			break;
938 		case LINE_TITLE_1:
939 			wrap_text(tab, "# ", l);
940 			break;
941 		case LINE_TITLE_2:
942 			wrap_text(tab, "## ", l);
943 			break;
944 		case LINE_TITLE_3:
945 			wrap_text(tab, "### ", l);
946 			break;
947 		case LINE_ITEM:
948 			wrap_text(tab, "* ", l);
949 			break;
950 		case LINE_QUOTE:
951 			wrap_text(tab, "> ", l);
952 			break;
953 		case LINE_PRE_START:
954 		case LINE_PRE_END:
955                         push_line(tab, l, NULL, 0);
956 			break;
957 		case LINE_PRE_CONTENT:
958                         hardwrap_text(tab, l);
959 			break;
960 		}
961 	}
962 	return 1;
963 }
964 
965 static inline void
966 print_line(struct line *l)
967 {
968 	const char *text = l->line;
969 
970 	if (text == NULL)
971 		text = "";
972 
973 	switch (l->type) {
974 	case LINE_TEXT:
975 		wprintw(body, "%s", text);
976 		break;
977 	case LINE_LINK:
978 		wattron(body, A_UNDERLINE);
979 		wprintw(body, "=> %s", text);
980 		wattroff(body, A_UNDERLINE);
981 		return;
982 	case LINE_TITLE_1:
983 		wattron(body, A_BOLD);
984 		wprintw(body, "# %s", text);
985 		wattroff(body, A_BOLD);
986 		return;
987 	case LINE_TITLE_2:
988 		wattron(body, A_BOLD);
989 		wprintw(body, "## %s", text);
990 		wattroff(body, A_BOLD);
991 		return;
992 	case LINE_TITLE_3:
993 		wattron(body, A_BOLD);
994 		wprintw(body, "### %s", text);
995 		wattroff(body, A_BOLD);
996 		return;
997 	case LINE_ITEM:
998 		wprintw(body, "* %s", text);
999 		return;
1000 	case LINE_QUOTE:
1001 		wattron(body, A_DIM);
1002 		wprintw(body, "> %s", text);
1003 		wattroff(body, A_DIM);
1004 		return;
1005 	case LINE_PRE_START:
1006 	case LINE_PRE_END:
1007 		wprintw(body, "```");
1008 		return;
1009 	case LINE_PRE_CONTENT:
1010 		wprintw(body, "%s", text);
1011 		return;
1012 	}
1013 }
1014 
1015 static void
1016 redraw_tabline(void)
1017 {
1018 	wclear(tabline);
1019 	wbkgd(tabline, A_REVERSE);
1020 	mvwprintw(tabline, 0, 0, "TODO: tabs here");
1021 }
1022 
1023 static void
1024 redraw_modeline(struct tab *tab)
1025 {
1026 	int		 x, y, max_x, max_y;
1027 	const char	*mode = "text/gemini-mode";
1028 	const char	*spin = "-\\|/";
1029 
1030 	wclear(modeline);
1031 	wattron(modeline, A_REVERSE);
1032 	wmove(modeline, 0, 0);
1033 
1034 	wprintw(modeline, "-%c %s %s ",
1035 	    spin[tab->s->loading_anim_step], mode, tab->urlstr);
1036 	getyx(modeline, y, x);
1037 	getmaxyx(modeline, max_y, max_x);
1038 
1039 	(void)y;
1040 	(void)max_y;
1041 
1042 	for (; x < max_x; ++x)
1043 		waddstr(modeline, "-");
1044 }
1045 
1046 static void
1047 redraw_minibuffer(void)
1048 {
1049 	size_t skip = 0, off = 0;
1050 
1051 	wclear(minibuf);
1052 	if (!in_minibuffer)
1053 		goto message;
1054 
1055 	off = strlen(ministate.prompt);
1056 
1057 	while (ministate.off - skip > COLS / 2) {
1058 		skip += MIN(ministate.off/4, 1);
1059 	}
1060 
1061 	mvwprintw(minibuf, 0, 0, "%s%s", ministate.prompt,
1062 	    ministate.buf + skip);
1063 
1064 message:
1065 	if (ministate.curmesg != NULL) {
1066 		if (in_minibuffer)
1067 			wprintw(minibuf, "  [%s]", ministate.curmesg);
1068 		else
1069 			wprintw(minibuf, "%s", ministate.curmesg);
1070 	}
1071 
1072 	wmove(minibuf, 0, off + ministate.off - skip);
1073 }
1074 
1075 static void
1076 redraw_tab(struct tab *tab)
1077 {
1078 	struct line	*l;
1079 	int		 line;
1080 
1081 	werase(body);
1082 
1083 	tab->s->line_off = MIN(tab->s->line_max, tab->s->line_off);
1084 	if (TAILQ_EMPTY(&tab->s->head))
1085 		return;
1086 
1087 	line = 0;
1088 	l = nth_line(tab, tab->s->line_off);
1089 	for (; l != NULL; l = TAILQ_NEXT(l, lines)) {
1090 		wmove(body, line, 0);
1091 		print_line(l);
1092 		line++;
1093 		if (line == body_lines)
1094 			break;
1095 	}
1096 
1097 	redraw_tabline();
1098 	redraw_modeline(tab);
1099 	redraw_minibuffer();
1100 
1101 	restore_cursor(tab);
1102 	wrefresh(tabline);
1103 	wrefresh(modeline);
1104 
1105 	if (in_minibuffer) {
1106 		wrefresh(body);
1107 		wrefresh(minibuf);
1108 	} else {
1109 		wrefresh(minibuf);
1110 		wrefresh(body);
1111 	}
1112 }
1113 
1114 static void
1115 message(const char *fmt, ...)
1116 {
1117 	va_list ap;
1118 
1119 	if (clminibufev_set)
1120 		evtimer_del(&clminibufev);
1121 	evtimer_set(&clminibufev, handle_clear_minibuf, NULL);
1122 	evtimer_add(&clminibufev, &clminibufev_timer);
1123 	clminibufev_set = 1;
1124 
1125 	va_start(ap, fmt);
1126 	/* TODO: what to do if the allocation fails here? */
1127 	if (vasprintf(&ministate.curmesg, fmt, ap) == -1)
1128 		ministate.curmesg = NULL;
1129 	va_end(ap);
1130 
1131 	redraw_minibuffer();
1132 
1133 	if (in_minibuffer) {
1134 		wrefresh(body);
1135 		wrefresh(minibuf);
1136 	} else {
1137 		wrefresh(minibuf);
1138 		wrefresh(body);
1139 	}
1140 }
1141 
1142 static void
1143 start_loading_anim(struct tab *tab)
1144 {
1145 	if (tab->s->loading_anim)
1146 		return;
1147 	tab->s->loading_anim = 1;
1148 	evtimer_set(&tab->s->loadingev, update_loading_anim, tab);
1149 	evtimer_add(&tab->s->loadingev, &loadingev_timer);
1150 }
1151 
1152 static void
1153 update_loading_anim(int fd, short ev, void *d)
1154 {
1155 	struct tab	*tab = d;
1156 
1157 	tab->s->loading_anim_step = (tab->s->loading_anim_step+1)%4;
1158 
1159 	redraw_modeline(tab);
1160 	wrefresh(modeline);
1161 
1162 	wrefresh(body);
1163 	if (in_minibuffer)
1164 		wrefresh(minibuf);
1165 
1166 	evtimer_add(&tab->s->loadingev, &loadingev_timer);
1167 }
1168 
1169 static void
1170 stop_loading_anim(struct tab *tab)
1171 {
1172 	if (!tab->s->loading_anim)
1173 		return;
1174 	evtimer_del(&tab->s->loadingev);
1175 	tab->s->loading_anim = 0;
1176 	tab->s->loading_anim_step = 0;
1177 
1178 	redraw_modeline(tab);
1179 
1180 	wrefresh(modeline);
1181 	wrefresh(body);
1182 	if (in_minibuffer)
1183 		wrefresh(minibuf);
1184 }
1185 
1186 static void
1187 load_url_in_tab(struct tab *tab, const char *url)
1188 {
1189 	empty_vlist(tab);
1190 	message("Loading %s...", url);
1191 	start_loading_anim(tab);
1192 	load_url(tab, url);
1193 
1194 	tab->s->curs_x = 0;
1195 	tab->s->curs_y = 0;
1196 	redraw_tab(tab);
1197 }
1198 
1199 static void
1200 enter_minibuffer(void (*self_insert_fn)(void), void (*donefn)(void),
1201     void (*abortfn)(void))
1202 {
1203 	in_minibuffer = 1;
1204 	base_map = &minibuffer_map;
1205 	current_map = &minibuffer_map;
1206 
1207 	base_map->unhandled_input = self_insert_fn;
1208 
1209 	ministate.donefn = donefn;
1210 	ministate.abortfn = abortfn;
1211 	memset(ministate.buf, 0, sizeof(ministate.buf));
1212         ministate.off = 0;
1213 	strlcpy(ministate.buf, "", sizeof(ministate.prompt));
1214 }
1215 
1216 static void
1217 exit_minibuffer(void)
1218 {
1219 	wclear(minibuf);
1220 
1221 	in_minibuffer = 0;
1222 	base_map = &global_map;
1223 	current_map = &global_map;
1224 }
1225 
1226 static void
1227 new_tab(void)
1228 {
1229 	struct tab	*tab, *t;
1230 	const char	*url = "about:new";
1231 
1232 	if ((tab = calloc(1, sizeof(*tab))) == NULL)
1233 		goto err;
1234 
1235 	if ((tab->s = calloc(1, sizeof(*t->s))) == NULL)
1236 		goto err;
1237 
1238 	TAILQ_INIT(&tab->s->head);
1239 	TAILQ_FOREACH(t, &tabshead, tabs) {
1240 		t->flags &= ~TAB_CURRENT;
1241 	}
1242 
1243 	tab->id = tab_counter++;
1244 	tab->flags = TAB_CURRENT;
1245 
1246 	if (TAILQ_EMPTY(&tabshead))
1247 		TAILQ_INSERT_HEAD(&tabshead, tab, tabs);
1248 	else
1249 		TAILQ_INSERT_TAIL(&tabshead, tab, tabs);
1250 
1251 	load_url_in_tab(tab, url);
1252 	return;
1253 
1254 err:
1255 	event_loopbreak();
1256 }
1257 
1258 int
1259 ui_init(void)
1260 {
1261 	setlocale(LC_ALL, "");
1262 
1263 	TAILQ_INIT(&global_map.m);
1264 	global_map.unhandled_input = global_key_unbound;
1265 
1266 	TAILQ_INIT(&minibuffer_map.m);
1267 
1268 	base_map = &global_map;
1269 	current_map = &global_map;
1270 	load_default_keys();
1271 
1272 	initscr();
1273 	raw();
1274 	noecho();
1275 
1276 	nonl();
1277 	intrflush(stdscr, FALSE);
1278 
1279 	if ((tabline = newwin(1, COLS, 0, 0)) == NULL)
1280 		return 0;
1281 	if ((body = newwin(LINES - 3, COLS, 1, 0)) == NULL)
1282 		return 0;
1283 	if ((modeline = newwin(1, COLS, LINES-2, 0)) == NULL)
1284 		return 0;
1285 	if ((minibuf = newwin(1, COLS, LINES-1, 0)) == NULL)
1286 		return 0;
1287 
1288 	body_lines = LINES-3;
1289 	body_cols = COLS;
1290 
1291 	keypad(body, TRUE);
1292 	scrollok(body, TRUE);
1293 
1294 	/* non-blocking input */
1295 	wtimeout(body, 0);
1296 
1297 	mvwprintw(body, 0, 0, "");
1298 
1299 	event_set(&stdioev, 0, EV_READ | EV_PERSIST, dispatch_stdio, NULL);
1300 	event_add(&stdioev, NULL);
1301 
1302 	signal_set(&winchev, SIGWINCH, handle_resize, NULL);
1303 	signal_add(&winchev, NULL);
1304 
1305 	new_tab();
1306 
1307 	return 1;
1308 }
1309 
1310 void
1311 ui_on_tab_loaded(struct tab *tab)
1312 {
1313 	stop_loading_anim(tab);
1314 	message("Loaded %s", tab->urlstr);
1315 }
1316 
1317 void
1318 ui_on_tab_refresh(struct tab *tab)
1319 {
1320 	if (!(tab->flags & TAB_CURRENT))
1321 		return;
1322 
1323 	wrap_page(tab);
1324 	redraw_tab(tab);
1325 }
1326 
1327 void
1328 ui_end(void)
1329 {
1330 	endwin();
1331 }