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Date:: Wed Jul 14 14:05:35 2021 UTC
Message:: refactor struct vline the new `meta.data' field will be useful for holding completions data.
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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  * Text scrolling
21  * ==============
22  *
23  * ncurses allows you to scroll a window, but when a line goes out of
24  * the visible area it's forgotten.  We keep a list of formatted lines
25  * (``visual lines'') that we know fits in the window, and draw them.
26  *
27  * This means that on every resize we have to clear our list of lines
28  * and re-render everything.  A clever approach would be to do this
29  * ``on-demand'', but it's still missing.
30  *
31  */
32 
33 #include <assert.h>
34 #include <curses.h>
35 #include <event.h>
36 #include <locale.h>
37 #include <signal.h>
38 #include <stdarg.h>
39 #include <stdlib.h>
40 #include <string.h>
41 #include <unistd.h>
42 
43 #include "defaults.h"
44 #include "minibuffer.h"
45 #include "telescope.h"
46 #include "ui.h"
47 #include "utf8.h"
48 
49 static struct event	stdioev, winchev;
50 
51 static void		 restore_curs_x(struct buffer *);
52 
53 static struct vline	*nth_line(struct buffer*, size_t);
54 static int		 readkey(void);
55 static void		 dispatch_stdio(int, short, void*);
56 static void		 handle_clear_echoarea(int, short, void*);
57 static void		 handle_resize(int, short, void*);
58 static void		 handle_resize_nodelay(int, short, void*);
59 static int		 wrap_page(struct buffer*, int);
60 static void		 print_vline(int, int, WINDOW*, struct vline*);
61 static void		 redraw_tabline(void);
62 static void		 redraw_window(WINDOW*, int, int, int, struct buffer*);
63 static void		 redraw_help(void);
64 static void		 redraw_body(struct tab*);
65 static void		 redraw_modeline(struct tab*);
66 static void		 redraw_minibuffer(void);
67 static void		 do_redraw_echoarea(void);
68 static void		 do_redraw_minibuffer(void);
69 static void		 do_redraw_minibuffer_compl(void);
70 static void		 place_cursor(int);
71 static void		 redraw_tab(struct tab*);
72 static void		 emit_help_item(char*, void*);
73 static void		 rec_compute_help(struct kmap*, char*, size_t);
74 static void		 recompute_help(void);
75 static void		 update_loading_anim(int, short, void*);
76 static void		 stop_loading_anim(struct tab*);
77 
78 static int		 too_small;
79 static int		 x_offset;
80 
81 struct thiskey thiskey;
82 
83 static struct event	resizeev;
84 static struct timeval	resize_timer = { 0, 250000 };
85 
86 static WINDOW	*tabline, *body, *modeline, *echoarea, *minibuffer;
87 
88 int			 body_lines, body_cols;
89 
90 static WINDOW		*help;
91 static struct buffer	 helpwin;
92 static int		 help_lines, help_cols;
93 
94 static int		 side_window;
95 
96 static struct event	clechoev;
97 static struct timeval	clechoev_timer = { 5, 0 };
98 static struct timeval	loadingev_timer = { 0, 250000 };
99 
100 static uint32_t		 tab_counter;
101 
102 static char	keybuf[64];
103 
104 struct kmap global_map,
105 	minibuffer_map,
106 	*current_map,
107 	*base_map;
108 
109 int in_minibuffer;
110 
111 static inline void
112 update_x_offset(void)
113 {
114 	if (olivetti_mode && fill_column < body_cols)
115 		x_offset = (body_cols - fill_column)/2;
116 	else
117 		x_offset = 0;
118 }
119 
120 void
121 save_excursion(struct excursion *place, struct buffer *buffer)
122 {
123 	place->curs_x = buffer->curs_x;
124 	place->curs_y = buffer->curs_y;
125 	place->line_off = buffer->line_off;
126 	place->current_line = buffer->current_line;
127 	place->cpoff = buffer->cpoff;
128 }
129 
130 void
131 restore_excursion(struct excursion *place, struct buffer *buffer)
132 {
133 	buffer->curs_x = place->curs_x;
134 	buffer->curs_y = place->curs_y;
135 	buffer->line_off = place->line_off;
136 	buffer->current_line = place->current_line;
137 	buffer->cpoff = place->cpoff;
138 }
139 
140 static void
141 restore_curs_x(struct buffer *buffer)
142 {
143 	struct vline	*vl;
144 	const char	*prfx;
145 
146 	vl = buffer->current_line;
147 	if (vl == NULL || vl->line == NULL)
148 		buffer->curs_x = buffer->cpoff = 0;
149 	else
150 		buffer->curs_x = utf8_snwidth(vl->line, buffer->cpoff);
151 
152 	buffer->curs_x += x_offset;
153 
154 	if (vl != NULL) {
155 		prfx = line_prefixes[vl->parent->type].prfx1;
156 		buffer->curs_x += utf8_swidth(prfx);
157 	}
158 }
159 
160 void
161 global_key_unbound(void)
162 {
163 	message("%s is undefined", keybuf);
164 }
165 
166 static struct vline *
167 nth_line(struct buffer *buffer, size_t n)
168 {
169 	struct vline	*vl;
170 	size_t		 i;
171 
172 	i = 0;
173 	TAILQ_FOREACH(vl, &buffer->head, vlines) {
174 		if (i == n)
175 			return vl;
176 		i++;
177 	}
178 
179 	/* unreachable */
180 	abort();
181 }
182 
183 struct tab *
184 current_tab(void)
185 {
186 	struct tab *t;
187 
188 	TAILQ_FOREACH(t, &tabshead, tabs) {
189 		if (t->flags & TAB_CURRENT)
190 			return t;
191 	}
192 
193 	/* unreachable */
194 	abort();
195 }
196 
197 struct buffer *
198 current_buffer(void)
199 {
200 	if (in_minibuffer)
201 		return &ministate.buffer;
202 	return &current_tab()->buffer;
203 }
204 
205 static int
206 readkey(void)
207 {
208 	uint32_t state = 0;
209 
210 	if ((thiskey.key = wgetch(body)) == ERR)
211 		return 0;
212 
213 	thiskey.meta = thiskey.key == 27;
214 	if (thiskey.meta) {
215 		thiskey.key = wgetch(body);
216 		if (thiskey.key == ERR || thiskey.key == 27) {
217 			thiskey.meta = 0;
218 			thiskey.key = 27;
219 		}
220 	}
221 
222 	thiskey.cp = 0;
223 	if ((unsigned int)thiskey.key < UINT8_MAX) {
224 		while (1) {
225 			if (!utf8_decode(&state, &thiskey.cp, (uint8_t)thiskey.key))
226 				break;
227 			if ((thiskey.key = wgetch(body)) == ERR) {
228 				message("Error decoding user input");
229 				return 0;
230 			}
231 		}
232 	}
233 
234 	return 1;
235 }
236 
237 static void
238 dispatch_stdio(int fd, short ev, void *d)
239 {
240 	struct keymap	*k;
241 	const char	*keyname;
242 	char		 tmp[5] = {0};
243 
244 	/* TODO: schedule a redraw? */
245 	if (too_small)
246 		return;
247 
248 	if (!readkey())
249 		return;
250 
251 	if (keybuf[0] != '\0')
252 		strlcat(keybuf, " ", sizeof(keybuf));
253 	if (thiskey.meta)
254 		strlcat(keybuf, "M-", sizeof(keybuf));
255 	if (thiskey.cp != 0) {
256 		utf8_encode(thiskey.cp, tmp);
257 		strlcat(keybuf, tmp, sizeof(keybuf));
258 	} else if ((keyname = unkbd(thiskey.key)) != NULL) {
259 		strlcat(keybuf, keyname, sizeof(keybuf));
260 	} else {
261 		tmp[0] = thiskey.key;
262 		strlcat(keybuf, tmp, sizeof(keybuf));
263 	}
264 
265 	TAILQ_FOREACH(k, &current_map->m, keymaps) {
266 		if (k->meta == thiskey.meta &&
267 		    k->key == thiskey.key) {
268 			if (k->fn == NULL)
269 				current_map = &k->map;
270 			else {
271 				current_map = base_map;
272 				strlcpy(keybuf, "", sizeof(keybuf));
273 				k->fn(current_buffer());
274 			}
275 			goto done;
276 		}
277 	}
278 
279 	if (current_map->unhandled_input != NULL)
280 		current_map->unhandled_input();
281 	else
282 		global_key_unbound();
283 
284 	strlcpy(keybuf, "", sizeof(keybuf));
285 	current_map = base_map;
286 
287 done:
288 	if (side_window)
289 		recompute_help();
290 
291 	redraw_tab(current_tab());
292 }
293 
294 static void
295 handle_clear_echoarea(int fd, short ev, void *d)
296 {
297 	free(ministate.curmesg);
298 	ministate.curmesg = NULL;
299 
300 	redraw_minibuffer();
301 	place_cursor(0);
302 }
303 
304 static void
305 handle_resize(int sig, short ev, void *d)
306 {
307 	if (event_pending(&resizeev, EV_TIMEOUT, NULL)) {
308 		event_del(&resizeev);
309 	}
310 	evtimer_set(&resizeev, handle_resize_nodelay, NULL);
311 	evtimer_add(&resizeev, &resize_timer);
312 }
313 
314 static void
315 handle_resize_nodelay(int s, short ev, void *d)
316 {
317 	struct tab	*tab;
318 	int		 lines;
319 
320 	endwin();
321 	refresh();
322 	clear();
323 
324 	lines = LINES;
325 
326 	if ((too_small = lines < 15)) {
327 		erase();
328 		printw("Window too small.");
329 		refresh();
330 		return;
331 	}
332 
333 	/* move and resize the windows, in reverse order! */
334 
335 	if (in_minibuffer == MB_COMPREAD) {
336 		mvwin(minibuffer, lines-10, 0);
337 		wresize(minibuffer, 10, COLS);
338 		lines -= 10;
339 
340 		wrap_page(&ministate.compl.buffer, COLS);
341 	}
342 
343 	mvwin(echoarea, --lines, 0);
344 	wresize(echoarea, 1, COLS);
345 
346 	mvwin(modeline, --lines, 0);
347 	wresize(modeline, 1, COLS);
348 
349 	body_lines = --lines;
350 	body_cols = COLS;
351 
352 	if (side_window) {
353 		help_cols = 0.3 * COLS;
354 		help_lines = lines;
355 		mvwin(help, 1, 0);
356 		wresize(help, help_lines, help_cols);
357 
358 		wrap_page(&helpwin, help_cols);
359 
360 		body_cols = COLS - help_cols - 1;
361 		mvwin(body, 1, help_cols);
362 	} else
363 		mvwin(body, 1, 0);
364 
365 	update_x_offset();
366 	wresize(body, body_lines, body_cols);
367 
368 	wresize(tabline, 1, COLS);
369 
370 	tab = current_tab();
371 
372 	wrap_page(&tab->buffer, body_cols);
373 	redraw_tab(tab);
374 }
375 
376 static int
377 wrap_page(struct buffer *buffer, int width)
378 {
379 	struct line		*l;
380 	const struct line	*top_orig, *orig;
381 	struct vline		*vl;
382 	int			 pre_width;
383 	const char		*prfx;
384 
385 	top_orig = buffer->top_line == NULL ? NULL : buffer->top_line->parent;
386 	orig = buffer->current_line == NULL ? NULL : buffer->current_line->parent;
387 
388 	buffer->top_line = NULL;
389 	buffer->current_line = NULL;
390 
391 	buffer->force_redraw = 1;
392 	buffer->curs_y = 0;
393 	buffer->line_off = 0;
394 
395 	empty_vlist(buffer);
396 
397 	TAILQ_FOREACH(l, &buffer->page.head, lines) {
398 		prfx = line_prefixes[l->type].prfx1;
399 		switch (l->type) {
400 		case LINE_TEXT:
401 		case LINE_LINK:
402 		case LINE_TITLE_1:
403 		case LINE_TITLE_2:
404 		case LINE_TITLE_3:
405 		case LINE_ITEM:
406 		case LINE_QUOTE:
407 		case LINE_PRE_START:
408 		case LINE_PRE_END:
409 			wrap_text(buffer, prfx, l, MIN(fill_column, width));
410 			break;
411 		case LINE_PRE_CONTENT:
412 			if (olivetti_mode)
413 				pre_width = MIN(fill_column, width);
414 			else
415 				pre_width = width;
416 			hardwrap_text(buffer, l, pre_width);
417 			break;
418 		case LINE_COMPL:
419 		case LINE_COMPL_CURRENT:
420 			wrap_one(buffer, prfx, l, width);
421 			break;
422 		}
423 
424 		if (top_orig == l && buffer->top_line == NULL) {
425 			buffer->line_off = buffer->line_max-1;
426 			buffer->top_line = TAILQ_LAST(&buffer->head, vhead);
427 
428 			while (1) {
429 				vl = TAILQ_PREV(buffer->top_line, vhead, vlines);
430 				if (vl == NULL || vl->parent != orig)
431 					break;
432 				buffer->top_line = vl;
433 				buffer->line_off--;
434 			}
435 		}
436 
437 		if (orig == l && buffer->current_line == NULL) {
438 			buffer->current_line = TAILQ_LAST(&buffer->head, vhead);
439 
440 			while (1) {
441 				vl = TAILQ_PREV(buffer->current_line, vhead, vlines);
442 				if (vl == NULL || vl->parent != orig)
443 					break;
444 				buffer->current_line = vl;
445 			}
446 		}
447 	}
448 
449         if (buffer->current_line == NULL)
450 		buffer->current_line = TAILQ_FIRST(&buffer->head);
451 
452 	if (buffer->top_line == NULL)
453 		buffer->top_line = buffer->current_line;
454 
455 	return 1;
456 }
457 
458 static void
459 print_vline(int off, int width, WINDOW *window, struct vline *vl)
460 {
461 	const char *text;
462 	const char *prfx;
463 	struct line_face *f;
464 	int i, left, x, y;
465 
466 	f = &line_faces[vl->parent->type];
467 
468 	/* unused, set by getyx */
469 	(void)y;
470 
471 	if (!vl->flags)
472 		prfx = line_prefixes[vl->parent->type].prfx1;
473 	else
474 		prfx = line_prefixes[vl->parent->type].prfx2;
475 
476 	text = vl->line;
477 	if (text == NULL)
478 		text = "";
479 
480 	wattr_on(window, body_face.left, NULL);
481 	for (i = 0; i < off; i++)
482 		waddch(window, ' ');
483 	wattr_off(window, body_face.left, NULL);
484 
485 	wattr_on(window, f->prefix, NULL);
486 	wprintw(window, "%s", prfx);
487 	wattr_off(window, f->prefix, NULL);
488 
489 	wattr_on(window, f->text, NULL);
490 	wprintw(window, "%s", text);
491 	wattr_off(window, f->text, NULL);
492 
493 	getyx(window, y, x);
494 
495 	left = width - x;
496 
497 	wattr_on(window, f->trail, NULL);
498 	for (i = 0; i < left - off; ++i)
499 		waddch(window, ' ');
500 	wattr_off(window, f->trail, NULL);
501 
502 	wattr_on(window, body_face.right, NULL);
503 	for (i = 0; i < off; i++)
504 		waddch(window, ' ');
505 	wattr_off(window, body_face.right, NULL);
506 
507 }
508 
509 static void
510 redraw_tabline(void)
511 {
512 	struct tab	*tab;
513 	size_t		 toskip, ots, tabwidth, space, x;
514 	int		 current, y, truncated;
515 	const char	*title;
516 	char		 buf[25];
517 
518 	x = 0;
519 
520 	/* unused, but setted by a getyx */
521 	(void)y;
522 
523 	tabwidth = sizeof(buf)+1;
524 	space = COLS-2;
525 
526 	toskip = 0;
527 	TAILQ_FOREACH(tab, &tabshead, tabs) {
528 		toskip++;
529 		if (tab->flags & TAB_CURRENT)
530 			break;
531 	}
532 
533 	if (toskip * tabwidth < space)
534 		toskip = 0;
535 	else {
536 		ots = toskip;
537 		toskip--;
538                 while (toskip != 0 &&
539 		    (ots - toskip+1) * tabwidth < space)
540 			toskip--;
541 	}
542 
543 	werase(tabline);
544 	wattr_on(tabline, tab_face.background, NULL);
545 	wprintw(tabline, toskip == 0 ? " " : "<");
546 	wattr_off(tabline, tab_face.background, NULL);
547 
548 	truncated = 0;
549 	TAILQ_FOREACH(tab, &tabshead, tabs) {
550 		if (truncated)
551 			break;
552 		if (toskip != 0) {
553 			toskip--;
554 			continue;
555 		}
556 
557 		getyx(tabline, y, x);
558 		if (x + sizeof(buf)+2 >= (size_t)COLS)
559 			truncated = 1;
560 
561 		current = tab->flags & TAB_CURRENT;
562 
563 		if (*(title = tab->buffer.page.title) == '\0')
564 			title = tab->hist_cur->h;
565 
566 		if (tab->flags & TAB_URGENT)
567 			strlcpy(buf, "!", sizeof(buf));
568 		else
569 			strlcpy(buf, " ", sizeof(buf));
570 
571                 if (strlcat(buf, title, sizeof(buf)) >= sizeof(buf)) {
572 			/* truncation happens */
573 			strlcpy(&buf[sizeof(buf)-4], "...", 4);
574 		} else {
575 			/* pad with spaces */
576 			while (strlcat(buf, "    ", sizeof(buf)) < sizeof(buf))
577 				/* nop */ ;
578 		}
579 
580 		if (current)
581 			wattr_on(tabline, tab_face.current, NULL);
582 		else
583 			wattr_on(tabline, tab_face.tab, NULL);
584 
585 		wprintw(tabline, "%s", buf);
586 		if (TAILQ_NEXT(tab, tabs) != NULL)
587 			wprintw(tabline, " ");
588 
589 		if (current)
590 			wattr_off(tabline, tab_face.current, NULL);
591 		else
592 			wattr_off(tabline, tab_face.tab, NULL);
593 	}
594 
595 	wattr_on(tabline, tab_face.background, NULL);
596 	for (; x < (size_t)COLS; ++x)
597 		waddch(tabline, ' ');
598 	if (truncated)
599 		mvwprintw(tabline, 0, COLS-1, ">");
600 	wattr_off(tabline, tab_face.background, NULL);
601 }
602 
603 /*
604  * Compute the first visible line around vl.  Try to search forward
605  * until the end of the buffer; if a visible line is not found, search
606  * backward.  Return NULL if no viable line was found.
607  */
608 struct vline *
609 adjust_line(struct vline *vl, struct buffer *buffer)
610 {
611 	struct vline *t;
612 
613 	if (vl == NULL)
614 		return NULL;
615 
616 	if (!(vl->parent->flags & L_HIDDEN))
617 		return vl;
618 
619 	/* search forward */
620 	for (t = vl;
621 	     t != NULL && t->parent->flags & L_HIDDEN;
622 	     t = TAILQ_NEXT(t, vlines))
623 		;		/* nop */
624 
625 	if (t != NULL)
626 		return t;
627 
628 	/* search backward */
629 	for (t = vl;
630 	     t != NULL && t->parent->flags & L_HIDDEN;
631 	     t = TAILQ_PREV(t, vhead, vlines))
632 		;		/* nop */
633 
634 	return t;
635 }
636 
637 static void
638 redraw_window(WINDOW *win, int off, int height, int width, struct buffer *buffer)
639 {
640         struct vline	*vl;
641 	int		 l, onscreen;
642 
643 	restore_curs_x(buffer);
644 
645 	/*
646 	 * TODO: ignoring buffer->force_update and always
647 	 * re-rendering.  In theory we can recompute the y position
648 	 * without a re-render, and optimize here.  It's not the only
649 	 * optimisation possible here, wscrl wolud also be an
650 	 * interesting one.
651 	 */
652 
653 again:
654 	werase(win);
655 	buffer->curs_y = 0;
656 
657 	if (TAILQ_EMPTY(&buffer->head))
658 		goto end;
659 
660 	if (buffer->top_line == NULL)
661 		buffer->top_line = TAILQ_FIRST(&buffer->head);
662 
663 	buffer->top_line = adjust_line(buffer->top_line, buffer);
664 	if (buffer->top_line == NULL)
665 		goto end;
666 
667 	buffer->current_line = adjust_line(buffer->current_line, buffer);
668 
669 	l = 0;
670 	onscreen = 0;
671 	for (vl = buffer->top_line; vl != NULL; vl = TAILQ_NEXT(vl, vlines)) {
672 		if (vl->parent->flags & L_HIDDEN)
673 			continue;
674 
675 		wmove(win, l, 0);
676 		print_vline(off, width, win, vl);
677 
678 		if (vl == buffer->current_line)
679 			onscreen = 1;
680 
681 		if (!onscreen)
682 			buffer->curs_y++;
683 
684 		l++;
685 		if (l == height)
686 			break;
687 	}
688 
689 	if (!onscreen) {
690 		for (; vl != NULL; vl = TAILQ_NEXT(vl, vlines)) {
691 			if (vl == buffer->current_line)
692 				break;
693 			if (vl->parent->flags & L_HIDDEN)
694 				continue;
695 			buffer->line_off++;
696 			buffer->top_line = TAILQ_NEXT(buffer->top_line, vlines);
697 		}
698 
699 		if (vl != NULL)
700 			goto again;
701 	}
702 
703 	buffer->last_line_off = buffer->line_off;
704 	buffer->force_redraw = 0;
705 end:
706 	wmove(win, buffer->curs_y, buffer->curs_x);
707 }
708 
709 static void
710 redraw_help(void)
711 {
712 	redraw_window(help, 0, help_lines, help_cols, &helpwin);
713 }
714 
715 static void
716 redraw_body(struct tab *tab)
717 {
718 	static struct tab *last_tab;
719 
720 	if (last_tab != tab)
721 		tab->buffer.force_redraw =1;
722 	last_tab = tab;
723 
724 	redraw_window(body, x_offset, body_lines, body_cols, &tab->buffer);
725 }
726 
727 static inline char
728 trust_status_char(enum trust_state ts)
729 {
730 	switch (ts) {
731 	case TS_UNKNOWN:	return 'u';
732 	case TS_UNTRUSTED:	return '!';
733 	case TS_TEMP_TRUSTED:	return '!';
734 	case TS_TRUSTED:	return 'v';
735 	case TS_VERIFIED:	return 'V';
736 	default:		return 'X';
737 	}
738 }
739 
740 static void
741 redraw_modeline(struct tab *tab)
742 {
743 	double		 pct;
744 	int		 x, y, max_x, max_y;
745 	const char	*mode = tab->buffer.page.name;
746 	const char	*spin = "-\\|/";
747 
748 	werase(modeline);
749 	wattr_on(modeline, modeline_face.background, NULL);
750 	wmove(modeline, 0, 0);
751 
752 	wprintw(modeline, "-%c%c %s ",
753 	    spin[tab->loading_anim_step],
754 	    trust_status_char(tab->trust),
755 	    mode == NULL ? "(none)" : mode);
756 
757 	pct = (tab->buffer.line_off + tab->buffer.curs_y) * 100.0
758 		/ tab->buffer.line_max;
759 
760 	if (tab->buffer.line_max <= (size_t)body_lines)
761                 wprintw(modeline, "All ");
762 	else if (tab->buffer.line_off == 0)
763                 wprintw(modeline, "Top ");
764 	else if (tab->buffer.line_off + body_lines >= tab->buffer.line_max)
765 		wprintw(modeline, "Bottom ");
766 	else
767 		wprintw(modeline, "%.0f%% ", pct);
768 
769 	wprintw(modeline, "%d/%d %s ",
770 	    tab->buffer.line_off + tab->buffer.curs_y,
771 	    tab->buffer.line_max,
772 	    tab->hist_cur->h);
773 
774 	getyx(modeline, y, x);
775 	getmaxyx(modeline, max_y, max_x);
776 
777 	(void)y;
778 	(void)max_y;
779 
780 	for (; x < max_x; ++x)
781 		waddstr(modeline, "-");
782 
783 	wattr_off(modeline, modeline_face.background, NULL);
784 }
785 
786 static void
787 redraw_minibuffer(void)
788 {
789 	wattr_on(echoarea, minibuffer_face.background, NULL);
790 	werase(echoarea);
791 
792 	if (in_minibuffer)
793 		do_redraw_minibuffer();
794 	else
795 		do_redraw_echoarea();
796 
797 	if (in_minibuffer == MB_COMPREAD)
798 		do_redraw_minibuffer_compl();
799 
800 	wattr_off(echoarea, minibuffer_face.background, NULL);
801 }
802 
803 static void
804 do_redraw_echoarea(void)
805 {
806 	struct tab *tab;
807 
808 	if (ministate.curmesg != NULL)
809                 wprintw(echoarea, "%s", ministate.curmesg);
810 	else if (*keybuf != '\0')
811 		waddstr(echoarea, keybuf);
812 	else {
813 		/* If nothing else, show the URL at point */
814 		tab = current_tab();
815 		if (tab->buffer.current_line != NULL &&
816 		    tab->buffer.current_line->parent->type == LINE_LINK)
817 			waddstr(echoarea,
818 			    tab->buffer.current_line->parent->meta.alt);
819 	}
820 }
821 
822 static void
823 do_redraw_minibuffer(void)
824 {
825 	size_t		 off_y, off_x = 0;
826 	const char	*start, *c;
827 
828 	/* unused, set by getyx */
829 	(void)off_y;
830 
831 	mvwprintw(echoarea, 0, 0, "%s", ministate.prompt);
832 	if (ministate.hist_cur != NULL)
833 		wprintw(echoarea, "(%zu/%zu) ",
834 		    ministate.hist_off + 1,
835 		    ministate.history->len);
836 
837 	getyx(echoarea, off_y, off_x);
838 
839 	start = ministate.hist_cur != NULL
840 		? ministate.hist_cur->h
841 		: ministate.buf;
842 	c = utf8_nth(ministate.buffer.current_line->line,
843 	    ministate.buffer.cpoff);
844 	while (utf8_swidth_between(start, c) > (size_t)COLS/2) {
845 		start = utf8_next_cp(start);
846 	}
847 
848 	waddstr(echoarea, start);
849 
850 	if (ministate.curmesg != NULL)
851 		wprintw(echoarea, " [%s]", ministate.curmesg);
852 
853 	wmove(echoarea, 0, off_x + utf8_swidth_between(start, c));
854 }
855 
856 static void
857 do_redraw_minibuffer_compl(void)
858 {
859 	redraw_window(minibuffer, 0, 10, body_cols,
860 	    &ministate.compl.buffer);
861 }
862 
863 /*
864  * Place the cursor in the right ncurses window.  If soft is 1, use
865  * wnoutrefresh (which shouldn't cause any I/O); otherwise use
866  * wrefresh.
867  */
868 static void
869 place_cursor(int soft)
870 {
871 	int (*touch)(WINDOW *);
872 
873 	if (soft)
874 		touch = wnoutrefresh;
875 	else
876 		touch = wrefresh;
877 
878 	if (in_minibuffer) {
879 		touch(body);
880 		touch(echoarea);
881 	} else {
882 		touch(echoarea);
883 		touch(body);
884 	}
885 }
886 
887 static void
888 redraw_tab(struct tab *tab)
889 {
890 	if (too_small)
891 		return;
892 
893 	if (side_window) {
894 		redraw_help();
895 		wnoutrefresh(help);
896 	}
897 
898 	redraw_tabline();
899 	redraw_body(tab);
900 	redraw_modeline(tab);
901 	redraw_minibuffer();
902 
903 	wnoutrefresh(tabline);
904 	wnoutrefresh(modeline);
905 
906 	if (in_minibuffer == MB_COMPREAD)
907 		wnoutrefresh(minibuffer);
908 
909 	place_cursor(1);
910 
911 	doupdate();
912 }
913 
914 static void
915 emit_help_item(char *prfx, void *fn)
916 {
917 	struct line	*l;
918 	struct cmd	*cmd;
919 
920 	for (cmd = cmds; cmd->cmd != NULL; ++cmd) {
921 		if (fn == cmd->fn)
922 			break;
923 	}
924 	assert(cmd != NULL);
925 
926 	if ((l = calloc(1, sizeof(*l))) == NULL)
927 		abort();
928 
929 	l->type = LINE_TEXT;
930 	l->meta.alt = NULL;
931 
932 	asprintf(&l->line, "%s %s", prfx, cmd->cmd);
933 
934 	if (TAILQ_EMPTY(&helpwin.page.head))
935 		TAILQ_INSERT_HEAD(&helpwin.page.head, l, lines);
936 	else
937 		TAILQ_INSERT_TAIL(&helpwin.page.head, l, lines);
938 }
939 
940 static void
941 rec_compute_help(struct kmap *keymap, char *prfx, size_t len)
942 {
943 	struct keymap	*k;
944 	char		 p[32];
945 	const char	*kn;
946 
947 	TAILQ_FOREACH(k, &keymap->m, keymaps) {
948 		strlcpy(p, prfx, sizeof(p));
949 		if (*p != '\0')
950 			strlcat(p, " ", sizeof(p));
951 		if (k->meta)
952 			strlcat(p, "M-", sizeof(p));
953 		if ((kn = unkbd(k->key)) != NULL)
954 			strlcat(p, kn, sizeof(p));
955 		else
956 			strlcat(p, keyname(k->key), sizeof(p));
957 
958 		if (k->fn == NULL)
959 			rec_compute_help(&k->map, p, sizeof(p));
960 		else
961 			emit_help_item(p, k->fn);
962 	}
963 }
964 
965 static void
966 recompute_help(void)
967 {
968 	char	p[32] = { 0 };
969 
970 	empty_vlist(&helpwin);
971 	empty_linelist(&helpwin);
972 	rec_compute_help(current_map, p, sizeof(p));
973 	wrap_page(&helpwin, help_cols);
974 }
975 
976 void
977 vmessage(const char *fmt, va_list ap)
978 {
979 	if (evtimer_pending(&clechoev, NULL))
980 		evtimer_del(&clechoev);
981 
982 	free(ministate.curmesg);
983 	ministate.curmesg = NULL;
984 
985 	if (fmt != NULL) {
986 		evtimer_set(&clechoev, handle_clear_echoarea, NULL);
987 		evtimer_add(&clechoev, &clechoev_timer);
988 
989 		/* TODO: what to do if the allocation fails here? */
990 		if (vasprintf(&ministate.curmesg, fmt, ap) == -1)
991 			ministate.curmesg = NULL;
992 	}
993 
994 	redraw_minibuffer();
995         place_cursor(0);
996 }
997 
998 void
999 message(const char *fmt, ...)
1000 {
1001 	va_list ap;
1002 
1003 	va_start(ap, fmt);
1004 	vmessage(fmt, ap);
1005 	va_end(ap);
1006 }
1007 
1008 void
1009 start_loading_anim(struct tab *tab)
1010 {
1011 	if (tab->loading_anim)
1012 		return;
1013 	tab->loading_anim = 1;
1014 	evtimer_set(&tab->loadingev, update_loading_anim, tab);
1015 	evtimer_add(&tab->loadingev, &loadingev_timer);
1016 }
1017 
1018 static void
1019 update_loading_anim(int fd, short ev, void *d)
1020 {
1021 	struct tab	*tab = d;
1022 
1023 	tab->loading_anim_step = (tab->loading_anim_step+1)%4;
1024 
1025 	if (tab->flags & TAB_CURRENT) {
1026 		redraw_modeline(tab);
1027 		wrefresh(modeline);
1028 		wrefresh(body);
1029 		if (in_minibuffer)
1030 			wrefresh(echoarea);
1031 	}
1032 
1033 	evtimer_add(&tab->loadingev, &loadingev_timer);
1034 }
1035 
1036 static void
1037 stop_loading_anim(struct tab *tab)
1038 {
1039 	if (!tab->loading_anim)
1040 		return;
1041 	evtimer_del(&tab->loadingev);
1042 	tab->loading_anim = 0;
1043 	tab->loading_anim_step = 0;
1044 
1045 	if (!(tab->flags & TAB_CURRENT))
1046 		return;
1047 
1048 	redraw_modeline(tab);
1049 
1050 	wrefresh(modeline);
1051 	wrefresh(body);
1052 	if (in_minibuffer)
1053 		wrefresh(echoarea);
1054 }
1055 
1056 void
1057 load_url_in_tab(struct tab *tab, const char *url)
1058 {
1059 	message("Loading %s...", url);
1060 	start_loading_anim(tab);
1061 	load_url(tab, url);
1062 
1063 	tab->buffer.curs_x = 0;
1064 	tab->buffer.curs_y = 0;
1065 	redraw_tab(tab);
1066 }
1067 
1068 void
1069 switch_to_tab(struct tab *tab)
1070 {
1071 	struct tab	*t;
1072 
1073 	TAILQ_FOREACH(t, &tabshead, tabs) {
1074 		t->flags &= ~TAB_CURRENT;
1075 	}
1076 
1077 	tab->flags |= TAB_CURRENT;
1078 	tab->flags &= ~TAB_URGENT;
1079 }
1080 
1081 unsigned int
1082 tab_new_id(void)
1083 {
1084 	return tab_counter++;
1085 }
1086 
1087 struct tab *
1088 new_tab(const char *url)
1089 {
1090 	struct tab	*tab;
1091 
1092 	if ((tab = calloc(1, sizeof(*tab))) == NULL) {
1093 		event_loopbreak();
1094 		return NULL;
1095 	}
1096 	tab->fd = -1;
1097 
1098 	TAILQ_INIT(&tab->hist.head);
1099 
1100 	TAILQ_INIT(&tab->buffer.head);
1101 
1102 	tab->id = tab_new_id();
1103 	switch_to_tab(tab);
1104 
1105 	if (TAILQ_EMPTY(&tabshead))
1106 		TAILQ_INSERT_HEAD(&tabshead, tab, tabs);
1107 	else
1108 		TAILQ_INSERT_TAIL(&tabshead, tab, tabs);
1109 
1110 	load_url_in_tab(tab, url);
1111 	return tab;
1112 }
1113 
1114 int
1115 ui_init()
1116 {
1117 	setlocale(LC_ALL, "");
1118 
1119 	TAILQ_INIT(&eecmd_history.head);
1120 	TAILQ_INIT(&ir_history.head);
1121 	TAILQ_INIT(&lu_history.head);
1122 
1123 	ministate.line.type = LINE_TEXT;
1124 	ministate.vline.parent = &ministate.line;
1125 	ministate.buffer.current_line = &ministate.vline;
1126 
1127 	/* initialize help window */
1128 	TAILQ_INIT(&helpwin.head);
1129 
1130 	base_map = &global_map;
1131 	current_map = &global_map;
1132 
1133 	initscr();
1134 
1135 	if (enable_colors) {
1136 		if (has_colors()) {
1137 			start_color();
1138 			use_default_colors();
1139 		} else
1140 			enable_colors = 0;
1141 	}
1142 
1143 	config_apply_style();
1144 
1145 	raw();
1146 	noecho();
1147 	nonl();
1148 	intrflush(stdscr, FALSE);
1149 
1150 	if ((tabline = newwin(1, COLS, 0, 0)) == NULL)
1151 		return 0;
1152 	if ((body = newwin(LINES - 3, COLS, 1, 0)) == NULL)
1153 		return 0;
1154 	if ((modeline = newwin(1, COLS, LINES-2, 0)) == NULL)
1155 		return 0;
1156 	if ((echoarea = newwin(1, COLS, LINES-1, 0)) == NULL)
1157 		return 0;
1158 	if ((minibuffer = newwin(1, COLS, LINES-1, 0)) == NULL)
1159 		return 0;
1160 	if ((help = newwin(1, 1, 1, 0)) == NULL)
1161 		return 0;
1162 
1163 	body_lines = LINES-3;
1164 	body_cols = COLS;
1165 
1166 	wbkgd(body, body_face.body);
1167 	wbkgd(echoarea, minibuffer_face.background);
1168 
1169 	update_x_offset();
1170 
1171 	keypad(body, TRUE);
1172 	scrollok(body, FALSE);
1173 
1174 	/* non-blocking input */
1175 	wtimeout(body, 0);
1176 
1177 	mvwprintw(body, 0, 0, "");
1178 
1179 	event_set(&stdioev, 0, EV_READ | EV_PERSIST, dispatch_stdio, NULL);
1180 	event_add(&stdioev, NULL);
1181 
1182 	signal_set(&winchev, SIGWINCH, handle_resize, NULL);
1183 	signal_add(&winchev, NULL);
1184 
1185 	return 1;
1186 }
1187 
1188 void
1189 ui_on_tab_loaded(struct tab *tab)
1190 {
1191 	stop_loading_anim(tab);
1192 	message("Loaded %s", tab->hist_cur->h);
1193 
1194 	redraw_tabline();
1195 	wrefresh(tabline);
1196 	place_cursor(0);
1197 }
1198 
1199 void
1200 ui_on_tab_refresh(struct tab *tab)
1201 {
1202 	wrap_page(&tab->buffer, body_cols);
1203 	if (tab->flags & TAB_CURRENT)
1204 		redraw_tab(tab);
1205 	else
1206 		tab->flags |= TAB_URGENT;
1207 }
1208 
1209 const char *
1210 ui_keyname(int k)
1211 {
1212 	return keyname(k);
1213 }
1214 
1215 void
1216 ui_toggle_side_window(void)
1217 {
1218 	side_window = !side_window;
1219 	if (side_window)
1220 		recompute_help();
1221 
1222 	/*
1223 	 * ugly hack, but otherwise the window doesn't get updated
1224 	 * until I call handle_resize a second time (i.e. C-l).  I
1225 	 * will be happy to know why something like this is needed.
1226 	 */
1227 	handle_resize_nodelay(0, 0, NULL);
1228 	handle_resize_nodelay(0, 0, NULL);
1229 }
1230 
1231 void
1232 ui_schedule_redraw(void)
1233 {
1234 	struct timeval tv = {0, 0};
1235 
1236 	if (event_pending(&resizeev, EV_TIMEOUT, NULL))
1237 		event_del(&resizeev);
1238 
1239 	evtimer_set(&resizeev, handle_resize_nodelay, NULL);
1240 	evtimer_add(&resizeev, &tv);
1241 }
1242 
1243 void
1244 ui_require_input(struct tab *tab, int hide)
1245 {
1246 	/* TODO: hard-switching to another tab is ugly */
1247 	switch_to_tab(tab);
1248 
1249 	enter_minibuffer(ir_self_insert, ir_select, exit_minibuffer,
1250 	    &ir_history, NULL, NULL);
1251 	strlcpy(ministate.prompt, "Input required: ",
1252 	    sizeof(ministate.prompt));
1253 	redraw_tab(tab);
1254 }
1255 
1256 void
1257 ui_yornp(const char *prompt, void (*fn)(int, struct tab *),
1258     struct tab *data)
1259 {
1260 	yornp(prompt, fn, data);
1261 	redraw_tab(current_tab());
1262 }
1263 
1264 void
1265 ui_read(const char *prompt, void (*fn)(const char*, struct tab *),
1266     struct tab *data)
1267 {
1268 	completing_read(prompt, fn, data);
1269 	redraw_tab(current_tab());
1270 }
1271 
1272 void
1273 ui_end(void)
1274 {
1275 	endwin();
1276 }