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Date:: Tue Jul 13 16:38:55 2021 UTC
Message:: handle gracefully really small windows (< 15 lines)
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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, 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		 place_cursor(int);
70 static void		 redraw_tab(struct tab*);
71 static void		 emit_help_item(char*, void*);
72 static void		 rec_compute_help(struct kmap*, char*, size_t);
73 static void		 recompute_help(void);
74 static void		 update_loading_anim(int, short, void*);
75 static void		 stop_loading_anim(struct tab*);
76 
77 static int		 too_small;
78 static int		 x_offset;
79 
80 struct thiskey thiskey;
81 
82 static struct event	resizeev;
83 static struct timeval	resize_timer = { 0, 250000 };
84 
85 static WINDOW	*tabline, *body, *modeline, *echoarea, *minibuffer;
86 
87 int			 body_lines, body_cols;
88 
89 static WINDOW		*help;
90 static struct buffer	 helpwin;
91 static int		 help_lines, help_cols;
92 
93 static int		 side_window;
94 
95 static struct event	clechoev;
96 static struct timeval	clechoev_timer = { 5, 0 };
97 static struct timeval	loadingev_timer = { 0, 250000 };
98 
99 static uint32_t		 tab_counter;
100 
101 static char	keybuf[64];
102 
103 struct kmap global_map,
104 	minibuffer_map,
105 	*current_map,
106 	*base_map;
107 
108 int in_minibuffer;
109 
110 static inline void
111 update_x_offset(void)
112 {
113 	if (olivetti_mode && fill_column < body_cols)
114 		x_offset = (body_cols - fill_column)/2;
115 	else
116 		x_offset = 0;
117 }
118 
119 void
120 save_excursion(struct excursion *place, struct buffer *buffer)
121 {
122 	place->curs_x = buffer->curs_x;
123 	place->curs_y = buffer->curs_y;
124 	place->line_off = buffer->line_off;
125 	place->current_line = buffer->current_line;
126 	place->cpoff = buffer->cpoff;
127 }
128 
129 void
130 restore_excursion(struct excursion *place, struct buffer *buffer)
131 {
132 	buffer->curs_x = place->curs_x;
133 	buffer->curs_y = place->curs_y;
134 	buffer->line_off = place->line_off;
135 	buffer->current_line = place->current_line;
136 	buffer->cpoff = place->cpoff;
137 }
138 
139 static void
140 restore_curs_x(struct buffer *buffer)
141 {
142 	struct vline	*vl;
143 	const char	*prfx;
144 
145 	vl = buffer->current_line;
146 	if (vl == NULL || vl->line == NULL)
147 		buffer->curs_x = buffer->cpoff = 0;
148 	else
149 		buffer->curs_x = utf8_snwidth(vl->line, buffer->cpoff);
150 
151 	buffer->curs_x += x_offset;
152 
153 	if (vl != NULL) {
154 		prfx = line_prefixes[vl->parent->type].prfx1;
155 		buffer->curs_x += utf8_swidth(prfx);
156 	}
157 }
158 
159 void
160 global_key_unbound(void)
161 {
162 	message("%s is undefined", keybuf);
163 }
164 
165 static struct vline *
166 nth_line(struct buffer *buffer, size_t n)
167 {
168 	struct vline	*vl;
169 	size_t		 i;
170 
171 	i = 0;
172 	TAILQ_FOREACH(vl, &buffer->head, vlines) {
173 		if (i == n)
174 			return vl;
175 		i++;
176 	}
177 
178 	/* unreachable */
179 	abort();
180 }
181 
182 struct tab *
183 current_tab(void)
184 {
185 	struct tab *t;
186 
187 	TAILQ_FOREACH(t, &tabshead, tabs) {
188 		if (t->flags & TAB_CURRENT)
189 			return t;
190 	}
191 
192 	/* unreachable */
193 	abort();
194 }
195 
196 struct buffer *
197 current_buffer(void)
198 {
199 	if (in_minibuffer)
200 		return &ministate.buffer;
201 	return &current_tab()->buffer;
202 }
203 
204 static int
205 readkey(void)
206 {
207 	uint32_t state = 0;
208 
209 	if ((thiskey.key = wgetch(body)) == ERR)
210 		return 0;
211 
212 	thiskey.meta = thiskey.key == 27;
213 	if (thiskey.meta) {
214 		thiskey.key = wgetch(body);
215 		if (thiskey.key == ERR || thiskey.key == 27) {
216 			thiskey.meta = 0;
217 			thiskey.key = 27;
218 		}
219 	}
220 
221 	thiskey.cp = 0;
222 	if ((unsigned int)thiskey.key < UINT8_MAX) {
223 		while (1) {
224 			if (!utf8_decode(&state, &thiskey.cp, (uint8_t)thiskey.key))
225 				break;
226 			if ((thiskey.key = wgetch(body)) == ERR) {
227 				message("Error decoding user input");
228 				return 0;
229 			}
230 		}
231 	}
232 
233 	return 1;
234 }
235 
236 static void
237 dispatch_stdio(int fd, short ev, void *d)
238 {
239 	struct keymap	*k;
240 	const char	*keyname;
241 	char		 tmp[5] = {0};
242 
243 	/* TODO: schedule a redraw? */
244 	if (too_small)
245 		return;
246 
247 	if (!readkey())
248 		return;
249 
250 	if (keybuf[0] != '\0')
251 		strlcat(keybuf, " ", sizeof(keybuf));
252 	if (thiskey.meta)
253 		strlcat(keybuf, "M-", sizeof(keybuf));
254 	if (thiskey.cp != 0) {
255 		utf8_encode(thiskey.cp, tmp);
256 		strlcat(keybuf, tmp, sizeof(keybuf));
257 	} else {
258 		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 
266 	TAILQ_FOREACH(k, &current_map->m, keymaps) {
267 		if (k->meta == thiskey.meta &&
268 		    k->key == thiskey.key) {
269 			if (k->fn == NULL)
270 				current_map = &k->map;
271 			else {
272 				current_map = base_map;
273 				strlcpy(keybuf, "", sizeof(keybuf));
274 				k->fn(current_buffer());
275 			}
276 			goto done;
277 		}
278 	}
279 
280 	if (current_map->unhandled_input != NULL)
281 		current_map->unhandled_input();
282 	else
283 		global_key_unbound();
284 
285 	strlcpy(keybuf, "", sizeof(keybuf));
286 	current_map = base_map;
287 
288 done:
289 	if (side_window)
290 		recompute_help();
291 
292 	redraw_tab(current_tab());
293 }
294 
295 static void
296 handle_clear_echoarea(int fd, short ev, void *d)
297 {
298 	free(ministate.curmesg);
299 	ministate.curmesg = NULL;
300 
301 	redraw_minibuffer();
302 	place_cursor(0);
303 }
304 
305 static void
306 handle_resize(int sig, short ev, void *d)
307 {
308 	if (event_pending(&resizeev, EV_TIMEOUT, NULL)) {
309 		event_del(&resizeev);
310 	}
311 	evtimer_set(&resizeev, handle_resize_nodelay, NULL);
312 	evtimer_add(&resizeev, &resize_timer);
313 }
314 
315 static void
316 handle_resize_nodelay(int s, short ev, void *d)
317 {
318 	struct tab	*tab;
319 	int		 lines;
320 
321 	endwin();
322 	refresh();
323 	clear();
324 
325 	lines = LINES;
326 
327 	if ((too_small = lines < 15)) {
328 		erase();
329 		printw("Window too small.");
330 		refresh();
331 		return;
332 	}
333 
334 	/* move and resize the windows, in reverse order! */
335 
336 	mvwin(echoarea, --lines, 0);
337 	wresize(echoarea, 1, COLS);
338 
339 	mvwin(modeline, --lines, 0);
340 	wresize(modeline, 1, COLS);
341 
342 	body_lines = --lines;
343 	body_cols = COLS;
344 
345 	if (side_window) {
346 		help_cols = 0.3 * COLS;
347 		help_lines = lines;
348 		mvwin(help, 1, 0);
349 		wresize(help, help_lines, help_cols);
350 
351 		wrap_page(&helpwin, help_cols);
352 
353 		body_cols = COLS - help_cols - 1;
354 		mvwin(body, 1, help_cols);
355 	} else
356 		mvwin(body, 1, 0);
357 
358 	update_x_offset();
359 	wresize(body, body_lines, body_cols);
360 
361 	wresize(tabline, 1, COLS);
362 
363 	tab = current_tab();
364 
365 	wrap_page(&tab->buffer, body_cols);
366 	redraw_tab(tab);
367 }
368 
369 static int
370 wrap_page(struct buffer *buffer, int width)
371 {
372 	struct line		*l;
373 	const struct line	*top_orig, *orig;
374 	struct vline		*vl;
375 	int			 pre_width;
376 	const char		*prfx;
377 
378 	top_orig = buffer->top_line == NULL ? NULL : buffer->top_line->parent;
379 	orig = buffer->current_line == NULL ? NULL : buffer->current_line->parent;
380 
381 	buffer->top_line = NULL;
382 	buffer->current_line = NULL;
383 
384 	buffer->force_redraw = 1;
385 	buffer->curs_y = 0;
386 	buffer->line_off = 0;
387 
388 	empty_vlist(buffer);
389 
390 	TAILQ_FOREACH(l, &buffer->page.head, lines) {
391 		prfx = line_prefixes[l->type].prfx1;
392 		switch (l->type) {
393 		case LINE_TEXT:
394 		case LINE_LINK:
395 		case LINE_TITLE_1:
396 		case LINE_TITLE_2:
397 		case LINE_TITLE_3:
398 		case LINE_ITEM:
399 		case LINE_QUOTE:
400 		case LINE_PRE_START:
401 		case LINE_PRE_END:
402 			wrap_text(buffer, prfx, l, MIN(fill_column, width));
403 			break;
404 		case LINE_PRE_CONTENT:
405 			if (olivetti_mode)
406 				pre_width = MIN(fill_column, width);
407 			else
408 				pre_width = width;
409 			hardwrap_text(buffer, l, pre_width);
410 			break;
411 		}
412 
413 		if (top_orig == l && buffer->top_line == NULL) {
414 			buffer->line_off = buffer->line_max-1;
415 			buffer->top_line = TAILQ_LAST(&buffer->head, vhead);
416 
417 			while (1) {
418 				vl = TAILQ_PREV(buffer->top_line, vhead, vlines);
419 				if (vl == NULL || vl->parent != orig)
420 					break;
421 				buffer->top_line = vl;
422 				buffer->line_off--;
423 			}
424 		}
425 
426 		if (orig == l && buffer->current_line == NULL) {
427 			buffer->current_line = TAILQ_LAST(&buffer->head, vhead);
428 
429 			while (1) {
430 				vl = TAILQ_PREV(buffer->current_line, vhead, vlines);
431 				if (vl == NULL || vl->parent != orig)
432 					break;
433 				buffer->current_line = vl;
434 			}
435 		}
436 	}
437 
438         if (buffer->current_line == NULL)
439 		buffer->current_line = TAILQ_FIRST(&buffer->head);
440 
441 	if (buffer->top_line == NULL)
442 		buffer->top_line = buffer->current_line;
443 
444 	return 1;
445 }
446 
447 static void
448 print_vline(int off, int width, WINDOW *window, struct vline *vl)
449 {
450 	const char *text;
451 	const char *prfx;
452 	struct line_face *f;
453 	int i, left, x, y;
454 
455 	f = &line_faces[vl->parent->type];
456 
457 	/* unused, set by getyx */
458 	(void)y;
459 
460 	if (!vl->flags)
461 		prfx = line_prefixes[vl->parent->type].prfx1;
462 	else
463 		prfx = line_prefixes[vl->parent->type].prfx2;
464 
465 	text = vl->line;
466 	if (text == NULL)
467 		text = "";
468 
469 	wattr_on(window, body_face.left, NULL);
470 	for (i = 0; i < off; i++)
471 		waddch(window, ' ');
472 	wattr_off(window, body_face.left, NULL);
473 
474 	wattr_on(window, f->prefix, NULL);
475 	wprintw(window, "%s", prfx);
476 	wattr_off(window, f->prefix, NULL);
477 
478 	wattr_on(window, f->text, NULL);
479 	wprintw(window, "%s", text);
480 	wattr_off(window, f->text, NULL);
481 
482 	getyx(window, y, x);
483 
484 	left = width - x;
485 
486 	wattr_on(window, f->trail, NULL);
487 	for (i = 0; i < left - off; ++i)
488 		waddch(window, ' ');
489 	wattr_off(window, f->trail, NULL);
490 
491 	wattr_on(window, body_face.right, NULL);
492 	for (i = 0; i < off; i++)
493 		waddch(window, ' ');
494 	wattr_off(window, body_face.right, NULL);
495 
496 }
497 
498 static void
499 redraw_tabline(void)
500 {
501 	struct tab	*tab;
502 	size_t		 toskip, ots, tabwidth, space, x;
503 	int		 current, y, truncated;
504 	const char	*title;
505 	char		 buf[25];
506 
507 	x = 0;
508 
509 	/* unused, but setted by a getyx */
510 	(void)y;
511 
512 	tabwidth = sizeof(buf)+1;
513 	space = COLS-2;
514 
515 	toskip = 0;
516 	TAILQ_FOREACH(tab, &tabshead, tabs) {
517 		toskip++;
518 		if (tab->flags & TAB_CURRENT)
519 			break;
520 	}
521 
522 	if (toskip * tabwidth < space)
523 		toskip = 0;
524 	else {
525 		ots = toskip;
526 		toskip--;
527                 while (toskip != 0 &&
528 		    (ots - toskip+1) * tabwidth < space)
529 			toskip--;
530 	}
531 
532 	werase(tabline);
533 	wattr_on(tabline, tab_face.background, NULL);
534 	wprintw(tabline, toskip == 0 ? " " : "<");
535 	wattr_off(tabline, tab_face.background, NULL);
536 
537 	truncated = 0;
538 	TAILQ_FOREACH(tab, &tabshead, tabs) {
539 		if (truncated)
540 			break;
541 		if (toskip != 0) {
542 			toskip--;
543 			continue;
544 		}
545 
546 		getyx(tabline, y, x);
547 		if (x + sizeof(buf)+2 >= (size_t)COLS)
548 			truncated = 1;
549 
550 		current = tab->flags & TAB_CURRENT;
551 
552 		if (*(title = tab->buffer.page.title) == '\0')
553 			title = tab->hist_cur->h;
554 
555 		if (tab->flags & TAB_URGENT)
556 			strlcpy(buf, "!", sizeof(buf));
557 		else
558 			strlcpy(buf, " ", sizeof(buf));
559 
560                 if (strlcat(buf, title, sizeof(buf)) >= sizeof(buf)) {
561 			/* truncation happens */
562 			strlcpy(&buf[sizeof(buf)-4], "...", 4);
563 		} else {
564 			/* pad with spaces */
565 			while (strlcat(buf, "    ", sizeof(buf)) < sizeof(buf))
566 				/* nop */ ;
567 		}
568 
569 		if (current)
570 			wattr_on(tabline, tab_face.current, NULL);
571 		else
572 			wattr_on(tabline, tab_face.tab, NULL);
573 
574 		wprintw(tabline, "%s", buf);
575 		if (TAILQ_NEXT(tab, tabs) != NULL)
576 			wprintw(tabline, " ");
577 
578 		if (current)
579 			wattr_off(tabline, tab_face.current, NULL);
580 		else
581 			wattr_off(tabline, tab_face.tab, NULL);
582 	}
583 
584 	wattr_on(tabline, tab_face.background, NULL);
585 	for (; x < (size_t)COLS; ++x)
586 		waddch(tabline, ' ');
587 	if (truncated)
588 		mvwprintw(tabline, 0, COLS-1, ">");
589 	wattr_off(tabline, tab_face.background, NULL);
590 }
591 
592 /*
593  * Compute the first visible line around vl.  Try to search forward
594  * until the end of the buffer; if a visible line is not found, search
595  * backward.  Return NULL if no viable line was found.
596  */
597 static inline struct vline *
598 adjust_line(struct vline *vl, struct buffer *buffer)
599 {
600 	struct vline *t;
601 
602 	if (!(vl->parent->flags & L_HIDDEN))
603 		return vl;
604 
605 	/* search forward */
606 	for (t = vl;
607 	     t != NULL && t->parent->flags & L_HIDDEN;
608 	     t = TAILQ_NEXT(t, vlines))
609 		;		/* nop */
610 
611 	if (t != NULL)
612 		return t;
613 
614 	/* search backward */
615 	for (t = vl;
616 	     t != NULL && t->parent->flags & L_HIDDEN;
617 	     t = TAILQ_PREV(t, vhead, vlines))
618 		;		/* nop */
619 
620 	return t;
621 }
622 
623 static void
624 redraw_window(WINDOW *win, int height, int width, struct buffer *buffer)
625 {
626         struct vline	*vl;
627 	int		 l, onscreen;
628 
629 	restore_curs_x(buffer);
630 
631 	/*
632 	 * TODO: ignoring buffer->force_update and always
633 	 * re-rendering.  In theory we can recompute the y position
634 	 * without a re-render, and optimize here.  It's not the only
635 	 * optimisation possible here, wscrl wolud also be an
636 	 * interesting one.
637 	 */
638 
639 again:
640 	werase(win);
641 	buffer->curs_y = 0;
642 
643 	if (TAILQ_EMPTY(&buffer->head))
644 		goto end;
645 
646 	buffer->top_line = adjust_line(buffer->top_line, buffer);
647 	if (buffer->top_line == NULL)
648 		goto end;
649 
650 	buffer->current_line = adjust_line(buffer->current_line, buffer);
651 
652 	l = 0;
653 	onscreen = 0;
654 	for (vl = buffer->top_line; vl != NULL; vl = TAILQ_NEXT(vl, vlines)) {
655 		if (vl->parent->flags & L_HIDDEN)
656 			continue;
657 
658 		wmove(win, l, 0);
659 		print_vline(x_offset, width, win, vl);
660 
661 		if (vl == buffer->current_line)
662 			onscreen = 1;
663 
664 		if (!onscreen)
665 			buffer->curs_y++;
666 
667 		l++;
668 		if (l == height)
669 			break;
670 	}
671 
672 	if (!onscreen) {
673 		for (; vl != NULL; vl = TAILQ_NEXT(vl, vlines)) {
674 			if (vl == buffer->current_line)
675 				break;
676 			if (vl->parent->flags & L_HIDDEN)
677 				continue;
678 			buffer->line_off++;
679 			buffer->top_line = TAILQ_NEXT(buffer->top_line, vlines);
680 		}
681 
682 		goto again;
683 	}
684 
685 	buffer->last_line_off = buffer->line_off;
686 	buffer->force_redraw = 0;
687 end:
688 	wmove(win, buffer->curs_y, buffer->curs_x);
689 }
690 
691 static void
692 redraw_help(void)
693 {
694 	redraw_window(help, help_lines, help_cols, &helpwin);
695 }
696 
697 static void
698 redraw_body(struct tab *tab)
699 {
700 	static struct tab *last_tab;
701 
702 	if (last_tab != tab)
703 		tab->buffer.force_redraw =1;
704 	last_tab = tab;
705 
706 	redraw_window(body, body_lines, body_cols, &tab->buffer);
707 }
708 
709 static inline char
710 trust_status_char(enum trust_state ts)
711 {
712 	switch (ts) {
713 	case TS_UNKNOWN:	return 'u';
714 	case TS_UNTRUSTED:	return '!';
715 	case TS_TEMP_TRUSTED:	return '!';
716 	case TS_TRUSTED:	return 'v';
717 	case TS_VERIFIED:	return 'V';
718 	default:		return 'X';
719 	}
720 }
721 
722 static void
723 redraw_modeline(struct tab *tab)
724 {
725 	double		 pct;
726 	int		 x, y, max_x, max_y;
727 	const char	*mode = tab->buffer.page.name;
728 	const char	*spin = "-\\|/";
729 
730 	werase(modeline);
731 	wattr_on(modeline, modeline_face.background, NULL);
732 	wmove(modeline, 0, 0);
733 
734 	wprintw(modeline, "-%c%c %s ",
735 	    spin[tab->loading_anim_step],
736 	    trust_status_char(tab->trust),
737 	    mode == NULL ? "(none)" : mode);
738 
739 	pct = (tab->buffer.line_off + tab->buffer.curs_y) * 100.0 / tab->buffer.line_max;
740 
741 	if (tab->buffer.line_max <= (size_t)body_lines)
742                 wprintw(modeline, "All ");
743 	else if (tab->buffer.line_off == 0)
744                 wprintw(modeline, "Top ");
745 	else if (tab->buffer.line_off + body_lines >= tab->buffer.line_max)
746 		wprintw(modeline, "Bottom ");
747 	else
748 		wprintw(modeline, "%.0f%% ", pct);
749 
750 	wprintw(modeline, "%d/%d %s ",
751 	    tab->buffer.line_off + tab->buffer.curs_y,
752 	    tab->buffer.line_max,
753 	    tab->hist_cur->h);
754 
755 	getyx(modeline, y, x);
756 	getmaxyx(modeline, max_y, max_x);
757 
758 	(void)y;
759 	(void)max_y;
760 
761 	for (; x < max_x; ++x)
762 		waddstr(modeline, "-");
763 
764 	wattr_off(modeline, modeline_face.background, NULL);
765 }
766 
767 static void
768 redraw_minibuffer(void)
769 {
770 	wattr_on(echoarea, minibuffer_face.background, NULL);
771 	werase(echoarea);
772 
773 	if (in_minibuffer)
774 		do_redraw_minibuffer();
775 	else
776 		do_redraw_echoarea();
777 
778 	wattr_off(echoarea, minibuffer_face.background, NULL);
779 }
780 
781 static void
782 do_redraw_echoarea(void)
783 {
784 	struct tab *tab;
785 
786 	if (ministate.curmesg != NULL)
787                 wprintw(echoarea, "%s", ministate.curmesg);
788 	else if (*keybuf != '\0')
789 		waddstr(echoarea, keybuf);
790 	else {
791 		/* If nothing else, show the URL at point */
792 		tab = current_tab();
793 		if (tab->buffer.current_line != NULL &&
794 		    tab->buffer.current_line->parent->type == LINE_LINK)
795 			waddstr(echoarea, tab->buffer.current_line->parent->alt);
796 	}
797 }
798 
799 static void
800 do_redraw_minibuffer(void)
801 {
802 	size_t		 off_y, off_x = 0;
803 	const char	*start, *c;
804 
805 	/* unused, set by getyx */
806 	(void)off_y;
807 
808 	mvwprintw(echoarea, 0, 0, "%s", ministate.prompt);
809 	if (ministate.hist_cur != NULL)
810 		wprintw(echoarea, "(%zu/%zu) ",
811 		    ministate.hist_off + 1,
812 		    ministate.history->len);
813 
814 	getyx(echoarea, off_y, off_x);
815 
816 	start = ministate.hist_cur != NULL
817 		? ministate.hist_cur->h
818 		: ministate.buf;
819 	c = utf8_nth(ministate.buffer.current_line->line,
820 	    ministate.buffer.cpoff);
821 	while (utf8_swidth_between(start, c) > (size_t)COLS/2) {
822 		start = utf8_next_cp(start);
823 	}
824 
825 	waddstr(echoarea, start);
826 
827 	if (ministate.curmesg != NULL)
828 		wprintw(echoarea, " [%s]", ministate.curmesg);
829 
830 	wmove(echoarea, 0, off_x + utf8_swidth_between(start, c));
831 }
832 
833 /*
834  * Place the cursor in the right ncurses window.  If soft is 1, use
835  * wnoutrefresh (which shouldn't cause any I/O); otherwise use
836  * wrefresh.
837  */
838 static void
839 place_cursor(int soft)
840 {
841 	int (*touch)(WINDOW *);
842 
843 	if (soft)
844 		touch = wnoutrefresh;
845 	else
846 		touch = wrefresh;
847 
848 	if (in_minibuffer) {
849 		touch(body);
850 		touch(echoarea);
851 	} else {
852 		touch(echoarea);
853 		touch(body);
854 	}
855 }
856 
857 static void
858 redraw_tab(struct tab *tab)
859 {
860 	if (too_small)
861 		return;
862 
863 	if (side_window) {
864 		redraw_help();
865 		wnoutrefresh(help);
866 	}
867 
868 	redraw_tabline();
869 	redraw_body(tab);
870 	redraw_modeline(tab);
871 	redraw_minibuffer();
872 
873 	wnoutrefresh(tabline);
874 	wnoutrefresh(modeline);
875 
876 	place_cursor(1);
877 
878 	doupdate();
879 }
880 
881 static void
882 emit_help_item(char *prfx, void *fn)
883 {
884 	struct line	*l;
885 	struct cmd	*cmd;
886 
887 	for (cmd = cmds; cmd->cmd != NULL; ++cmd) {
888 		if (fn == cmd->fn)
889 			break;
890 	}
891 	assert(cmd != NULL);
892 
893 	if ((l = calloc(1, sizeof(*l))) == NULL)
894 		abort();
895 
896 	l->type = LINE_TEXT;
897 	l->alt = NULL;
898 
899 	asprintf(&l->line, "%s %s", prfx, cmd->cmd);
900 
901 	if (TAILQ_EMPTY(&helpwin.page.head))
902 		TAILQ_INSERT_HEAD(&helpwin.page.head, l, lines);
903 	else
904 		TAILQ_INSERT_TAIL(&helpwin.page.head, l, lines);
905 }
906 
907 static void
908 rec_compute_help(struct kmap *keymap, char *prfx, size_t len)
909 {
910 	struct keymap	*k;
911 	char		 p[32];
912 	const char	*kn;
913 
914 	TAILQ_FOREACH(k, &keymap->m, keymaps) {
915 		strlcpy(p, prfx, sizeof(p));
916 		if (*p != '\0')
917 			strlcat(p, " ", sizeof(p));
918 		if (k->meta)
919 			strlcat(p, "M-", sizeof(p));
920 		if ((kn = unkbd(k->key)) != NULL)
921 			strlcat(p, kn, sizeof(p));
922 		else
923 			strlcat(p, keyname(k->key), sizeof(p));
924 
925 		if (k->fn == NULL)
926 			rec_compute_help(&k->map, p, sizeof(p));
927 		else
928 			emit_help_item(p, k->fn);
929 	}
930 }
931 
932 static void
933 recompute_help(void)
934 {
935 	char	p[32] = { 0 };
936 
937 	empty_vlist(&helpwin);
938 	empty_linelist(&helpwin);
939 	rec_compute_help(current_map, p, sizeof(p));
940 	wrap_page(&helpwin, help_cols);
941 }
942 
943 void
944 vmessage(const char *fmt, va_list ap)
945 {
946 	if (evtimer_pending(&clechoev, NULL))
947 		evtimer_del(&clechoev);
948 
949 	free(ministate.curmesg);
950 	ministate.curmesg = NULL;
951 
952 	if (fmt != NULL) {
953 		evtimer_set(&clechoev, handle_clear_echoarea, NULL);
954 		evtimer_add(&clechoev, &clechoev_timer);
955 
956 		/* TODO: what to do if the allocation fails here? */
957 		if (vasprintf(&ministate.curmesg, fmt, ap) == -1)
958 			ministate.curmesg = NULL;
959 	}
960 
961 	redraw_minibuffer();
962         place_cursor(0);
963 }
964 
965 void
966 message(const char *fmt, ...)
967 {
968 	va_list ap;
969 
970 	va_start(ap, fmt);
971 	vmessage(fmt, ap);
972 	va_end(ap);
973 }
974 
975 void
976 start_loading_anim(struct tab *tab)
977 {
978 	if (tab->loading_anim)
979 		return;
980 	tab->loading_anim = 1;
981 	evtimer_set(&tab->loadingev, update_loading_anim, tab);
982 	evtimer_add(&tab->loadingev, &loadingev_timer);
983 }
984 
985 static void
986 update_loading_anim(int fd, short ev, void *d)
987 {
988 	struct tab	*tab = d;
989 
990 	tab->loading_anim_step = (tab->loading_anim_step+1)%4;
991 
992 	if (tab->flags & TAB_CURRENT) {
993 		redraw_modeline(tab);
994 		wrefresh(modeline);
995 		wrefresh(body);
996 		if (in_minibuffer)
997 			wrefresh(echoarea);
998 	}
999 
1000 	evtimer_add(&tab->loadingev, &loadingev_timer);
1001 }
1002 
1003 static void
1004 stop_loading_anim(struct tab *tab)
1005 {
1006 	if (!tab->loading_anim)
1007 		return;
1008 	evtimer_del(&tab->loadingev);
1009 	tab->loading_anim = 0;
1010 	tab->loading_anim_step = 0;
1011 
1012 	if (!(tab->flags & TAB_CURRENT))
1013 		return;
1014 
1015 	redraw_modeline(tab);
1016 
1017 	wrefresh(modeline);
1018 	wrefresh(body);
1019 	if (in_minibuffer)
1020 		wrefresh(echoarea);
1021 }
1022 
1023 void
1024 load_url_in_tab(struct tab *tab, const char *url)
1025 {
1026 	message("Loading %s...", url);
1027 	start_loading_anim(tab);
1028 	load_url(tab, url);
1029 
1030 	tab->buffer.curs_x = 0;
1031 	tab->buffer.curs_y = 0;
1032 	redraw_tab(tab);
1033 }
1034 
1035 void
1036 switch_to_tab(struct tab *tab)
1037 {
1038 	struct tab	*t;
1039 
1040 	TAILQ_FOREACH(t, &tabshead, tabs) {
1041 		t->flags &= ~TAB_CURRENT;
1042 	}
1043 
1044 	tab->flags |= TAB_CURRENT;
1045 	tab->flags &= ~TAB_URGENT;
1046 }
1047 
1048 unsigned int
1049 tab_new_id(void)
1050 {
1051 	return tab_counter++;
1052 }
1053 
1054 struct tab *
1055 new_tab(const char *url)
1056 {
1057 	struct tab	*tab;
1058 
1059 	if ((tab = calloc(1, sizeof(*tab))) == NULL) {
1060 		event_loopbreak();
1061 		return NULL;
1062 	}
1063 	tab->fd = -1;
1064 
1065 	TAILQ_INIT(&tab->hist.head);
1066 
1067 	TAILQ_INIT(&tab->buffer.head);
1068 
1069 	tab->id = tab_new_id();
1070 	switch_to_tab(tab);
1071 
1072 	if (TAILQ_EMPTY(&tabshead))
1073 		TAILQ_INSERT_HEAD(&tabshead, tab, tabs);
1074 	else
1075 		TAILQ_INSERT_TAIL(&tabshead, tab, tabs);
1076 
1077 	load_url_in_tab(tab, url);
1078 	return tab;
1079 }
1080 
1081 int
1082 ui_init()
1083 {
1084 	setlocale(LC_ALL, "");
1085 
1086 	TAILQ_INIT(&eecmd_history.head);
1087 	TAILQ_INIT(&ir_history.head);
1088 	TAILQ_INIT(&lu_history.head);
1089 
1090 	ministate.line.type = LINE_TEXT;
1091 	ministate.vline.parent = &ministate.line;
1092 	ministate.buffer.current_line = &ministate.vline;
1093 
1094 	/* initialize help window */
1095 	TAILQ_INIT(&helpwin.head);
1096 
1097 	base_map = &global_map;
1098 	current_map = &global_map;
1099 
1100 	initscr();
1101 
1102 	if (enable_colors) {
1103 		if (has_colors()) {
1104 			start_color();
1105 			use_default_colors();
1106 		} else
1107 			enable_colors = 0;
1108 	}
1109 
1110 	config_apply_style();
1111 
1112 	raw();
1113 	noecho();
1114 	nonl();
1115 	intrflush(stdscr, FALSE);
1116 
1117 	if ((tabline = newwin(1, COLS, 0, 0)) == NULL)
1118 		return 0;
1119 	if ((body = newwin(LINES - 3, COLS, 1, 0)) == NULL)
1120 		return 0;
1121 	if ((modeline = newwin(1, COLS, LINES-2, 0)) == NULL)
1122 		return 0;
1123 	if ((echoarea = newwin(1, COLS, LINES-1, 0)) == NULL)
1124 		return 0;
1125 	if ((minibuffer = newwin(1, COLS, LINES-1, 0)) == NULL)
1126 		return 0;
1127 	if ((help = newwin(1, 1, 1, 0)) == NULL)
1128 		return 0;
1129 
1130 	body_lines = LINES-3;
1131 	body_cols = COLS;
1132 
1133 	wbkgd(body, body_face.body);
1134 	wbkgd(echoarea, minibuffer_face.background);
1135 
1136 	update_x_offset();
1137 
1138 	keypad(body, TRUE);
1139 	scrollok(body, FALSE);
1140 
1141 	/* non-blocking input */
1142 	wtimeout(body, 0);
1143 
1144 	mvwprintw(body, 0, 0, "");
1145 
1146 	event_set(&stdioev, 0, EV_READ | EV_PERSIST, dispatch_stdio, NULL);
1147 	event_add(&stdioev, NULL);
1148 
1149 	signal_set(&winchev, SIGWINCH, handle_resize, NULL);
1150 	signal_add(&winchev, NULL);
1151 
1152 	return 1;
1153 }
1154 
1155 void
1156 ui_on_tab_loaded(struct tab *tab)
1157 {
1158 	stop_loading_anim(tab);
1159 	message("Loaded %s", tab->hist_cur->h);
1160 
1161 	redraw_tabline();
1162 	wrefresh(tabline);
1163 	place_cursor(0);
1164 }
1165 
1166 void
1167 ui_on_tab_refresh(struct tab *tab)
1168 {
1169 	wrap_page(&tab->buffer, body_cols);
1170 	if (tab->flags & TAB_CURRENT)
1171 		redraw_tab(tab);
1172 	else
1173 		tab->flags |= TAB_URGENT;
1174 }
1175 
1176 const char *
1177 ui_keyname(int k)
1178 {
1179 	return keyname(k);
1180 }
1181 
1182 void
1183 ui_toggle_side_window(void)
1184 {
1185 	side_window = !side_window;
1186 	if (side_window)
1187 		recompute_help();
1188 
1189 	/*
1190 	 * ugly hack, but otherwise the window doesn't get updated
1191 	 * until I call handle_resize a second time (i.e. C-l).  I
1192 	 * will be happy to know why something like this is needed.
1193 	 */
1194 	handle_resize_nodelay(0, 0, NULL);
1195 	handle_resize_nodelay(0, 0, NULL);
1196 }
1197 
1198 void
1199 ui_schedule_redraw(void)
1200 {
1201 	handle_resize_nodelay(0, 0, NULL);
1202 }
1203 
1204 void
1205 ui_require_input(struct tab *tab, int hide)
1206 {
1207 	/* TODO: hard-switching to another tab is ugly */
1208 	switch_to_tab(tab);
1209 
1210 	enter_minibuffer(ir_self_insert, ir_select, exit_minibuffer,
1211 	    &ir_history, NULL, NULL);
1212 	strlcpy(ministate.prompt, "Input required: ",
1213 	    sizeof(ministate.prompt));
1214 	redraw_tab(tab);
1215 }
1216 
1217 void
1218 ui_yornp(const char *prompt, void (*fn)(int, struct tab *),
1219     struct tab *data)
1220 {
1221 	yornp(prompt, fn, data);
1222 	redraw_tab(current_tab());
1223 }
1224 
1225 void
1226 ui_read(const char *prompt, void (*fn)(const char*, struct tab *),
1227     struct tab *data)
1228 {
1229 	completing_read(prompt, fn, data, NULL, NULL);
1230 	redraw_tab(current_tab());
1231 }
1232 
1233 void
1234 ui_end(void)
1235 {
1236 	endwin();
1237 }