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Date:: Tue Jul 13 16:31:11 2021 UTC
Message:: foreshadowing: the "real" completing_read
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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		 x_offset;
78 
79 struct thiskey thiskey;
80 
81 static struct event	resizeev;
82 static struct timeval	resize_timer = { 0, 250000 };
83 
84 static WINDOW	*tabline, *body, *modeline, *echoarea, *minibuffer;
85 
86 int			 body_lines, body_cols;
87 
88 static WINDOW		*help;
89 static struct buffer	 helpwin;
90 static int		 help_lines, help_cols;
91 
92 static int		 side_window;
93 
94 static struct event	clechoev;
95 static struct timeval	clechoev_timer = { 5, 0 };
96 static struct timeval	loadingev_timer = { 0, 250000 };
97 
98 static uint32_t		 tab_counter;
99 
100 static char	keybuf[64];
101 
102 struct kmap global_map,
103 	minibuffer_map,
104 	*current_map,
105 	*base_map;
106 
107 int in_minibuffer;
108 
109 static inline void
110 update_x_offset(void)
111 {
112 	if (olivetti_mode && fill_column < body_cols)
113 		x_offset = (body_cols - fill_column)/2;
114 	else
115 		x_offset = 0;
116 }
117 
118 void
119 save_excursion(struct excursion *place, struct buffer *buffer)
120 {
121 	place->curs_x = buffer->curs_x;
122 	place->curs_y = buffer->curs_y;
123 	place->line_off = buffer->line_off;
124 	place->current_line = buffer->current_line;
125 	place->cpoff = buffer->cpoff;
126 }
127 
128 void
129 restore_excursion(struct excursion *place, struct buffer *buffer)
130 {
131 	buffer->curs_x = place->curs_x;
132 	buffer->curs_y = place->curs_y;
133 	buffer->line_off = place->line_off;
134 	buffer->current_line = place->current_line;
135 	buffer->cpoff = place->cpoff;
136 }
137 
138 static void
139 restore_curs_x(struct buffer *buffer)
140 {
141 	struct vline	*vl;
142 	const char	*prfx;
143 
144 	vl = buffer->current_line;
145 	if (vl == NULL || vl->line == NULL)
146 		buffer->curs_x = buffer->cpoff = 0;
147 	else
148 		buffer->curs_x = utf8_snwidth(vl->line, buffer->cpoff);
149 
150 	buffer->curs_x += x_offset;
151 
152 	if (vl != NULL) {
153 		prfx = line_prefixes[vl->parent->type].prfx1;
154 		buffer->curs_x += utf8_swidth(prfx);
155 	}
156 }
157 
158 void
159 global_key_unbound(void)
160 {
161 	message("%s is undefined", keybuf);
162 }
163 
164 static struct vline *
165 nth_line(struct buffer *buffer, size_t n)
166 {
167 	struct vline	*vl;
168 	size_t		 i;
169 
170 	i = 0;
171 	TAILQ_FOREACH(vl, &buffer->head, vlines) {
172 		if (i == n)
173 			return vl;
174 		i++;
175 	}
176 
177 	/* unreachable */
178 	abort();
179 }
180 
181 struct tab *
182 current_tab(void)
183 {
184 	struct tab *t;
185 
186 	TAILQ_FOREACH(t, &tabshead, tabs) {
187 		if (t->flags & TAB_CURRENT)
188 			return t;
189 	}
190 
191 	/* unreachable */
192 	abort();
193 }
194 
195 struct buffer *
196 current_buffer(void)
197 {
198 	if (in_minibuffer)
199 		return &ministate.buffer;
200 	return &current_tab()->buffer;
201 }
202 
203 static int
204 readkey(void)
205 {
206 	uint32_t state = 0;
207 
208 	if ((thiskey.key = wgetch(body)) == ERR)
209 		return 0;
210 
211 	thiskey.meta = thiskey.key == 27;
212 	if (thiskey.meta) {
213 		thiskey.key = wgetch(body);
214 		if (thiskey.key == ERR || thiskey.key == 27) {
215 			thiskey.meta = 0;
216 			thiskey.key = 27;
217 		}
218 	}
219 
220 	thiskey.cp = 0;
221 	if ((unsigned int)thiskey.key < UINT8_MAX) {
222 		while (1) {
223 			if (!utf8_decode(&state, &thiskey.cp, (uint8_t)thiskey.key))
224 				break;
225 			if ((thiskey.key = wgetch(body)) == ERR) {
226 				message("Error decoding user input");
227 				return 0;
228 			}
229 		}
230 	}
231 
232 	return 1;
233 }
234 
235 static void
236 dispatch_stdio(int fd, short ev, void *d)
237 {
238 	struct keymap	*k;
239 	const char	*keyname;
240 	char		 tmp[5] = {0};
241 
242 	if (!readkey())
243 		return;
244 
245 	if (keybuf[0] != '\0')
246 		strlcat(keybuf, " ", sizeof(keybuf));
247 	if (thiskey.meta)
248 		strlcat(keybuf, "M-", sizeof(keybuf));
249 	if (thiskey.cp != 0) {
250 		utf8_encode(thiskey.cp, tmp);
251 		strlcat(keybuf, tmp, sizeof(keybuf));
252 	} else {
253 		if ((keyname = unkbd(thiskey.key)) != NULL)
254 			strlcat(keybuf, keyname, sizeof(keybuf));
255 		else {
256 			tmp[0] = thiskey.key;
257 			strlcat(keybuf, tmp, sizeof(keybuf));
258 		}
259 	}
260 
261 	TAILQ_FOREACH(k, &current_map->m, keymaps) {
262 		if (k->meta == thiskey.meta &&
263 		    k->key == thiskey.key) {
264 			if (k->fn == NULL)
265 				current_map = &k->map;
266 			else {
267 				current_map = base_map;
268 				strlcpy(keybuf, "", sizeof(keybuf));
269 				k->fn(current_buffer());
270 			}
271 			goto done;
272 		}
273 	}
274 
275 	if (current_map->unhandled_input != NULL)
276 		current_map->unhandled_input();
277 	else
278 		global_key_unbound();
279 
280 	strlcpy(keybuf, "", sizeof(keybuf));
281 	current_map = base_map;
282 
283 done:
284 	if (side_window)
285 		recompute_help();
286 
287 	redraw_tab(current_tab());
288 }
289 
290 static void
291 handle_clear_echoarea(int fd, short ev, void *d)
292 {
293 	free(ministate.curmesg);
294 	ministate.curmesg = NULL;
295 
296 	redraw_minibuffer();
297 	place_cursor(0);
298 }
299 
300 static void
301 handle_resize(int sig, short ev, void *d)
302 {
303 	if (event_pending(&resizeev, EV_TIMEOUT, NULL)) {
304 		event_del(&resizeev);
305 	}
306 	evtimer_set(&resizeev, handle_resize_nodelay, NULL);
307 	evtimer_add(&resizeev, &resize_timer);
308 }
309 
310 static void
311 handle_resize_nodelay(int s, short ev, void *d)
312 {
313 	struct tab	*tab;
314 	int		 lines;
315 
316 	endwin();
317 	refresh();
318 	clear();
319 
320 	lines = LINES;
321 
322 	/* move and resize the windows, in reverse order! */
323 
324 	mvwin(echoarea, --lines, 0);
325 	wresize(echoarea, 1, COLS);
326 
327 	mvwin(modeline, --lines, 0);
328 	wresize(modeline, 1, COLS);
329 
330 	body_lines = --lines;
331 	body_cols = COLS;
332 
333 	if (side_window) {
334 		help_cols = 0.3 * COLS;
335 		help_lines = lines;
336 		mvwin(help, 1, 0);
337 		wresize(help, help_lines, help_cols);
338 
339 		wrap_page(&helpwin, help_cols);
340 
341 		body_cols = COLS - help_cols - 1;
342 		mvwin(body, 1, help_cols);
343 	} else
344 		mvwin(body, 1, 0);
345 
346 	update_x_offset();
347 	wresize(body, body_lines, body_cols);
348 
349 	wresize(tabline, 1, COLS);
350 
351 	tab = current_tab();
352 
353 	wrap_page(&tab->buffer, body_cols);
354 	redraw_tab(tab);
355 }
356 
357 static int
358 wrap_page(struct buffer *buffer, int width)
359 {
360 	struct line		*l;
361 	const struct line	*top_orig, *orig;
362 	struct vline		*vl;
363 	int			 pre_width;
364 	const char		*prfx;
365 
366 	top_orig = buffer->top_line == NULL ? NULL : buffer->top_line->parent;
367 	orig = buffer->current_line == NULL ? NULL : buffer->current_line->parent;
368 
369 	buffer->top_line = NULL;
370 	buffer->current_line = NULL;
371 
372 	buffer->force_redraw = 1;
373 	buffer->curs_y = 0;
374 	buffer->line_off = 0;
375 
376 	empty_vlist(buffer);
377 
378 	TAILQ_FOREACH(l, &buffer->page.head, lines) {
379 		prfx = line_prefixes[l->type].prfx1;
380 		switch (l->type) {
381 		case LINE_TEXT:
382 		case LINE_LINK:
383 		case LINE_TITLE_1:
384 		case LINE_TITLE_2:
385 		case LINE_TITLE_3:
386 		case LINE_ITEM:
387 		case LINE_QUOTE:
388 		case LINE_PRE_START:
389 		case LINE_PRE_END:
390 			wrap_text(buffer, prfx, l, MIN(fill_column, width));
391 			break;
392 		case LINE_PRE_CONTENT:
393 			if (olivetti_mode)
394 				pre_width = MIN(fill_column, width);
395 			else
396 				pre_width = width;
397 			hardwrap_text(buffer, l, pre_width);
398 			break;
399 		}
400 
401 		if (top_orig == l && buffer->top_line == NULL) {
402 			buffer->line_off = buffer->line_max-1;
403 			buffer->top_line = TAILQ_LAST(&buffer->head, vhead);
404 
405 			while (1) {
406 				vl = TAILQ_PREV(buffer->top_line, vhead, vlines);
407 				if (vl == NULL || vl->parent != orig)
408 					break;
409 				buffer->top_line = vl;
410 				buffer->line_off--;
411 			}
412 		}
413 
414 		if (orig == l && buffer->current_line == NULL) {
415 			buffer->current_line = TAILQ_LAST(&buffer->head, vhead);
416 
417 			while (1) {
418 				vl = TAILQ_PREV(buffer->current_line, vhead, vlines);
419 				if (vl == NULL || vl->parent != orig)
420 					break;
421 				buffer->current_line = vl;
422 			}
423 		}
424 	}
425 
426         if (buffer->current_line == NULL)
427 		buffer->current_line = TAILQ_FIRST(&buffer->head);
428 
429 	if (buffer->top_line == NULL)
430 		buffer->top_line = buffer->current_line;
431 
432 	return 1;
433 }
434 
435 static void
436 print_vline(int off, int width, WINDOW *window, struct vline *vl)
437 {
438 	const char *text;
439 	const char *prfx;
440 	struct line_face *f;
441 	int i, left, x, y;
442 
443 	f = &line_faces[vl->parent->type];
444 
445 	/* unused, set by getyx */
446 	(void)y;
447 
448 	if (!vl->flags)
449 		prfx = line_prefixes[vl->parent->type].prfx1;
450 	else
451 		prfx = line_prefixes[vl->parent->type].prfx2;
452 
453 	text = vl->line;
454 	if (text == NULL)
455 		text = "";
456 
457 	wattr_on(window, body_face.left, NULL);
458 	for (i = 0; i < off; i++)
459 		waddch(window, ' ');
460 	wattr_off(window, body_face.left, NULL);
461 
462 	wattr_on(window, f->prefix, NULL);
463 	wprintw(window, "%s", prfx);
464 	wattr_off(window, f->prefix, NULL);
465 
466 	wattr_on(window, f->text, NULL);
467 	wprintw(window, "%s", text);
468 	wattr_off(window, f->text, NULL);
469 
470 	getyx(window, y, x);
471 
472 	left = width - x;
473 
474 	wattr_on(window, f->trail, NULL);
475 	for (i = 0; i < left - off; ++i)
476 		waddch(window, ' ');
477 	wattr_off(window, f->trail, NULL);
478 
479 	wattr_on(window, body_face.right, NULL);
480 	for (i = 0; i < off; i++)
481 		waddch(window, ' ');
482 	wattr_off(window, body_face.right, NULL);
483 
484 }
485 
486 static void
487 redraw_tabline(void)
488 {
489 	struct tab	*tab;
490 	size_t		 toskip, ots, tabwidth, space, x;
491 	int		 current, y, truncated;
492 	const char	*title;
493 	char		 buf[25];
494 
495 	x = 0;
496 
497 	/* unused, but setted by a getyx */
498 	(void)y;
499 
500 	tabwidth = sizeof(buf)+1;
501 	space = COLS-2;
502 
503 	toskip = 0;
504 	TAILQ_FOREACH(tab, &tabshead, tabs) {
505 		toskip++;
506 		if (tab->flags & TAB_CURRENT)
507 			break;
508 	}
509 
510 	if (toskip * tabwidth < space)
511 		toskip = 0;
512 	else {
513 		ots = toskip;
514 		toskip--;
515                 while (toskip != 0 &&
516 		    (ots - toskip+1) * tabwidth < space)
517 			toskip--;
518 	}
519 
520 	werase(tabline);
521 	wattr_on(tabline, tab_face.background, NULL);
522 	wprintw(tabline, toskip == 0 ? " " : "<");
523 	wattr_off(tabline, tab_face.background, NULL);
524 
525 	truncated = 0;
526 	TAILQ_FOREACH(tab, &tabshead, tabs) {
527 		if (truncated)
528 			break;
529 		if (toskip != 0) {
530 			toskip--;
531 			continue;
532 		}
533 
534 		getyx(tabline, y, x);
535 		if (x + sizeof(buf)+2 >= (size_t)COLS)
536 			truncated = 1;
537 
538 		current = tab->flags & TAB_CURRENT;
539 
540 		if (*(title = tab->buffer.page.title) == '\0')
541 			title = tab->hist_cur->h;
542 
543 		if (tab->flags & TAB_URGENT)
544 			strlcpy(buf, "!", sizeof(buf));
545 		else
546 			strlcpy(buf, " ", sizeof(buf));
547 
548                 if (strlcat(buf, title, sizeof(buf)) >= sizeof(buf)) {
549 			/* truncation happens */
550 			strlcpy(&buf[sizeof(buf)-4], "...", 4);
551 		} else {
552 			/* pad with spaces */
553 			while (strlcat(buf, "    ", sizeof(buf)) < sizeof(buf))
554 				/* nop */ ;
555 		}
556 
557 		if (current)
558 			wattr_on(tabline, tab_face.current, NULL);
559 		else
560 			wattr_on(tabline, tab_face.tab, NULL);
561 
562 		wprintw(tabline, "%s", buf);
563 		if (TAILQ_NEXT(tab, tabs) != NULL)
564 			wprintw(tabline, " ");
565 
566 		if (current)
567 			wattr_off(tabline, tab_face.current, NULL);
568 		else
569 			wattr_off(tabline, tab_face.tab, NULL);
570 	}
571 
572 	wattr_on(tabline, tab_face.background, NULL);
573 	for (; x < (size_t)COLS; ++x)
574 		waddch(tabline, ' ');
575 	if (truncated)
576 		mvwprintw(tabline, 0, COLS-1, ">");
577 	wattr_off(tabline, tab_face.background, NULL);
578 }
579 
580 /*
581  * Compute the first visible line around vl.  Try to search forward
582  * until the end of the buffer; if a visible line is not found, search
583  * backward.  Return NULL if no viable line was found.
584  */
585 static inline struct vline *
586 adjust_line(struct vline *vl, struct buffer *buffer)
587 {
588 	struct vline *t;
589 
590 	if (!(vl->parent->flags & L_HIDDEN))
591 		return vl;
592 
593 	/* search forward */
594 	for (t = vl;
595 	     t != NULL && t->parent->flags & L_HIDDEN;
596 	     t = TAILQ_NEXT(t, vlines))
597 		;		/* nop */
598 
599 	if (t != NULL)
600 		return t;
601 
602 	/* search backward */
603 	for (t = vl;
604 	     t != NULL && t->parent->flags & L_HIDDEN;
605 	     t = TAILQ_PREV(t, vhead, vlines))
606 		;		/* nop */
607 
608 	return t;
609 }
610 
611 static void
612 redraw_window(WINDOW *win, int height, int width, struct buffer *buffer)
613 {
614         struct vline	*vl;
615 	int		 l, onscreen;
616 
617 	restore_curs_x(buffer);
618 
619 	/*
620 	 * TODO: ignoring buffer->force_update and always
621 	 * re-rendering.  In theory we can recompute the y position
622 	 * without a re-render, and optimize here.  It's not the only
623 	 * optimisation possible here, wscrl wolud also be an
624 	 * interesting one.
625 	 */
626 
627 again:
628 	werase(win);
629 	buffer->curs_y = 0;
630 
631 	if (TAILQ_EMPTY(&buffer->head))
632 		goto end;
633 
634 	buffer->top_line = adjust_line(buffer->top_line, buffer);
635 	if (buffer->top_line == NULL)
636 		goto end;
637 
638 	buffer->current_line = adjust_line(buffer->current_line, buffer);
639 
640 	l = 0;
641 	onscreen = 0;
642 	for (vl = buffer->top_line; vl != NULL; vl = TAILQ_NEXT(vl, vlines)) {
643 		if (vl->parent->flags & L_HIDDEN)
644 			continue;
645 
646 		wmove(win, l, 0);
647 		print_vline(x_offset, width, win, vl);
648 
649 		if (vl == buffer->current_line)
650 			onscreen = 1;
651 
652 		if (!onscreen)
653 			buffer->curs_y++;
654 
655 		l++;
656 		if (l == height)
657 			break;
658 	}
659 
660 	if (!onscreen) {
661 		for (; vl != NULL; vl = TAILQ_NEXT(vl, vlines)) {
662 			if (vl == buffer->current_line)
663 				break;
664 			if (vl->parent->flags & L_HIDDEN)
665 				continue;
666 			buffer->line_off++;
667 			buffer->top_line = TAILQ_NEXT(buffer->top_line, vlines);
668 		}
669 
670 		goto again;
671 	}
672 
673 	buffer->last_line_off = buffer->line_off;
674 	buffer->force_redraw = 0;
675 end:
676 	wmove(win, buffer->curs_y, buffer->curs_x);
677 }
678 
679 static void
680 redraw_help(void)
681 {
682 	redraw_window(help, help_lines, help_cols, &helpwin);
683 }
684 
685 static void
686 redraw_body(struct tab *tab)
687 {
688 	static struct tab *last_tab;
689 
690 	if (last_tab != tab)
691 		tab->buffer.force_redraw =1;
692 	last_tab = tab;
693 
694 	redraw_window(body, body_lines, body_cols, &tab->buffer);
695 }
696 
697 static inline char
698 trust_status_char(enum trust_state ts)
699 {
700 	switch (ts) {
701 	case TS_UNKNOWN:	return 'u';
702 	case TS_UNTRUSTED:	return '!';
703 	case TS_TEMP_TRUSTED:	return '!';
704 	case TS_TRUSTED:	return 'v';
705 	case TS_VERIFIED:	return 'V';
706 	default:		return 'X';
707 	}
708 }
709 
710 static void
711 redraw_modeline(struct tab *tab)
712 {
713 	double		 pct;
714 	int		 x, y, max_x, max_y;
715 	const char	*mode = tab->buffer.page.name;
716 	const char	*spin = "-\\|/";
717 
718 	werase(modeline);
719 	wattr_on(modeline, modeline_face.background, NULL);
720 	wmove(modeline, 0, 0);
721 
722 	wprintw(modeline, "-%c%c %s ",
723 	    spin[tab->loading_anim_step],
724 	    trust_status_char(tab->trust),
725 	    mode == NULL ? "(none)" : mode);
726 
727 	pct = (tab->buffer.line_off + tab->buffer.curs_y) * 100.0 / tab->buffer.line_max;
728 
729 	if (tab->buffer.line_max <= (size_t)body_lines)
730                 wprintw(modeline, "All ");
731 	else if (tab->buffer.line_off == 0)
732                 wprintw(modeline, "Top ");
733 	else if (tab->buffer.line_off + body_lines >= tab->buffer.line_max)
734 		wprintw(modeline, "Bottom ");
735 	else
736 		wprintw(modeline, "%.0f%% ", pct);
737 
738 	wprintw(modeline, "%d/%d %s ",
739 	    tab->buffer.line_off + tab->buffer.curs_y,
740 	    tab->buffer.line_max,
741 	    tab->hist_cur->h);
742 
743 	getyx(modeline, y, x);
744 	getmaxyx(modeline, max_y, max_x);
745 
746 	(void)y;
747 	(void)max_y;
748 
749 	for (; x < max_x; ++x)
750 		waddstr(modeline, "-");
751 
752 	wattr_off(modeline, modeline_face.background, NULL);
753 }
754 
755 static void
756 redraw_minibuffer(void)
757 {
758 	wattr_on(echoarea, minibuffer_face.background, NULL);
759 	werase(echoarea);
760 
761 	if (in_minibuffer)
762 		do_redraw_minibuffer();
763 	else
764 		do_redraw_echoarea();
765 
766 	wattr_off(echoarea, minibuffer_face.background, NULL);
767 }
768 
769 static void
770 do_redraw_echoarea(void)
771 {
772 	struct tab *tab;
773 
774 	if (ministate.curmesg != NULL)
775                 wprintw(echoarea, "%s", ministate.curmesg);
776 	else if (*keybuf != '\0')
777 		waddstr(echoarea, keybuf);
778 	else {
779 		/* If nothing else, show the URL at point */
780 		tab = current_tab();
781 		if (tab->buffer.current_line != NULL &&
782 		    tab->buffer.current_line->parent->type == LINE_LINK)
783 			waddstr(echoarea, tab->buffer.current_line->parent->alt);
784 	}
785 }
786 
787 static void
788 do_redraw_minibuffer(void)
789 {
790 	size_t		 off_y, off_x = 0;
791 	const char	*start, *c;
792 
793 	/* unused, set by getyx */
794 	(void)off_y;
795 
796 	mvwprintw(echoarea, 0, 0, "%s", ministate.prompt);
797 	if (ministate.hist_cur != NULL)
798 		wprintw(echoarea, "(%zu/%zu) ",
799 		    ministate.hist_off + 1,
800 		    ministate.history->len);
801 
802 	getyx(echoarea, off_y, off_x);
803 
804 	start = ministate.hist_cur != NULL
805 		? ministate.hist_cur->h
806 		: ministate.buf;
807 	c = utf8_nth(ministate.buffer.current_line->line,
808 	    ministate.buffer.cpoff);
809 	while (utf8_swidth_between(start, c) > (size_t)COLS/2) {
810 		start = utf8_next_cp(start);
811 	}
812 
813 	waddstr(echoarea, start);
814 
815 	if (ministate.curmesg != NULL)
816 		wprintw(echoarea, " [%s]", ministate.curmesg);
817 
818 	wmove(echoarea, 0, off_x + utf8_swidth_between(start, c));
819 }
820 
821 /*
822  * Place the cursor in the right ncurses window.  If soft is 1, use
823  * wnoutrefresh (which shouldn't cause any I/O); otherwise use
824  * wrefresh.
825  */
826 static void
827 place_cursor(int soft)
828 {
829 	int (*touch)(WINDOW *);
830 
831 	if (soft)
832 		touch = wnoutrefresh;
833 	else
834 		touch = wrefresh;
835 
836 	if (in_minibuffer) {
837 		touch(body);
838 		touch(echoarea);
839 	} else {
840 		touch(echoarea);
841 		touch(body);
842 	}
843 }
844 
845 static void
846 redraw_tab(struct tab *tab)
847 {
848 	if (side_window) {
849 		redraw_help();
850 		wnoutrefresh(help);
851 	}
852 
853 	redraw_tabline();
854 	redraw_body(tab);
855 	redraw_modeline(tab);
856 	redraw_minibuffer();
857 
858 	wnoutrefresh(tabline);
859 	wnoutrefresh(modeline);
860 
861 	place_cursor(1);
862 
863 	doupdate();
864 }
865 
866 static void
867 emit_help_item(char *prfx, void *fn)
868 {
869 	struct line	*l;
870 	struct cmd	*cmd;
871 
872 	for (cmd = cmds; cmd->cmd != NULL; ++cmd) {
873 		if (fn == cmd->fn)
874 			break;
875 	}
876 	assert(cmd != NULL);
877 
878 	if ((l = calloc(1, sizeof(*l))) == NULL)
879 		abort();
880 
881 	l->type = LINE_TEXT;
882 	l->alt = NULL;
883 
884 	asprintf(&l->line, "%s %s", prfx, cmd->cmd);
885 
886 	if (TAILQ_EMPTY(&helpwin.page.head))
887 		TAILQ_INSERT_HEAD(&helpwin.page.head, l, lines);
888 	else
889 		TAILQ_INSERT_TAIL(&helpwin.page.head, l, lines);
890 }
891 
892 static void
893 rec_compute_help(struct kmap *keymap, char *prfx, size_t len)
894 {
895 	struct keymap	*k;
896 	char		 p[32];
897 	const char	*kn;
898 
899 	TAILQ_FOREACH(k, &keymap->m, keymaps) {
900 		strlcpy(p, prfx, sizeof(p));
901 		if (*p != '\0')
902 			strlcat(p, " ", sizeof(p));
903 		if (k->meta)
904 			strlcat(p, "M-", sizeof(p));
905 		if ((kn = unkbd(k->key)) != NULL)
906 			strlcat(p, kn, sizeof(p));
907 		else
908 			strlcat(p, keyname(k->key), sizeof(p));
909 
910 		if (k->fn == NULL)
911 			rec_compute_help(&k->map, p, sizeof(p));
912 		else
913 			emit_help_item(p, k->fn);
914 	}
915 }
916 
917 static void
918 recompute_help(void)
919 {
920 	char	p[32] = { 0 };
921 
922 	empty_vlist(&helpwin);
923 	empty_linelist(&helpwin);
924 	rec_compute_help(current_map, p, sizeof(p));
925 	wrap_page(&helpwin, help_cols);
926 }
927 
928 void
929 vmessage(const char *fmt, va_list ap)
930 {
931 	if (evtimer_pending(&clechoev, NULL))
932 		evtimer_del(&clechoev);
933 
934 	free(ministate.curmesg);
935 	ministate.curmesg = NULL;
936 
937 	if (fmt != NULL) {
938 		evtimer_set(&clechoev, handle_clear_echoarea, NULL);
939 		evtimer_add(&clechoev, &clechoev_timer);
940 
941 		/* TODO: what to do if the allocation fails here? */
942 		if (vasprintf(&ministate.curmesg, fmt, ap) == -1)
943 			ministate.curmesg = NULL;
944 	}
945 
946 	redraw_minibuffer();
947         place_cursor(0);
948 }
949 
950 void
951 message(const char *fmt, ...)
952 {
953 	va_list ap;
954 
955 	va_start(ap, fmt);
956 	vmessage(fmt, ap);
957 	va_end(ap);
958 }
959 
960 void
961 start_loading_anim(struct tab *tab)
962 {
963 	if (tab->loading_anim)
964 		return;
965 	tab->loading_anim = 1;
966 	evtimer_set(&tab->loadingev, update_loading_anim, tab);
967 	evtimer_add(&tab->loadingev, &loadingev_timer);
968 }
969 
970 static void
971 update_loading_anim(int fd, short ev, void *d)
972 {
973 	struct tab	*tab = d;
974 
975 	tab->loading_anim_step = (tab->loading_anim_step+1)%4;
976 
977 	if (tab->flags & TAB_CURRENT) {
978 		redraw_modeline(tab);
979 		wrefresh(modeline);
980 		wrefresh(body);
981 		if (in_minibuffer)
982 			wrefresh(echoarea);
983 	}
984 
985 	evtimer_add(&tab->loadingev, &loadingev_timer);
986 }
987 
988 static void
989 stop_loading_anim(struct tab *tab)
990 {
991 	if (!tab->loading_anim)
992 		return;
993 	evtimer_del(&tab->loadingev);
994 	tab->loading_anim = 0;
995 	tab->loading_anim_step = 0;
996 
997 	if (!(tab->flags & TAB_CURRENT))
998 		return;
999 
1000 	redraw_modeline(tab);
1001 
1002 	wrefresh(modeline);
1003 	wrefresh(body);
1004 	if (in_minibuffer)
1005 		wrefresh(echoarea);
1006 }
1007 
1008 void
1009 load_url_in_tab(struct tab *tab, const char *url)
1010 {
1011 	message("Loading %s...", url);
1012 	start_loading_anim(tab);
1013 	load_url(tab, url);
1014 
1015 	tab->buffer.curs_x = 0;
1016 	tab->buffer.curs_y = 0;
1017 	redraw_tab(tab);
1018 }
1019 
1020 void
1021 switch_to_tab(struct tab *tab)
1022 {
1023 	struct tab	*t;
1024 
1025 	TAILQ_FOREACH(t, &tabshead, tabs) {
1026 		t->flags &= ~TAB_CURRENT;
1027 	}
1028 
1029 	tab->flags |= TAB_CURRENT;
1030 	tab->flags &= ~TAB_URGENT;
1031 }
1032 
1033 unsigned int
1034 tab_new_id(void)
1035 {
1036 	return tab_counter++;
1037 }
1038 
1039 struct tab *
1040 new_tab(const char *url)
1041 {
1042 	struct tab	*tab;
1043 
1044 	if ((tab = calloc(1, sizeof(*tab))) == NULL) {
1045 		event_loopbreak();
1046 		return NULL;
1047 	}
1048 	tab->fd = -1;
1049 
1050 	TAILQ_INIT(&tab->hist.head);
1051 
1052 	TAILQ_INIT(&tab->buffer.head);
1053 
1054 	tab->id = tab_new_id();
1055 	switch_to_tab(tab);
1056 
1057 	if (TAILQ_EMPTY(&tabshead))
1058 		TAILQ_INSERT_HEAD(&tabshead, tab, tabs);
1059 	else
1060 		TAILQ_INSERT_TAIL(&tabshead, tab, tabs);
1061 
1062 	load_url_in_tab(tab, url);
1063 	return tab;
1064 }
1065 
1066 int
1067 ui_init()
1068 {
1069 	setlocale(LC_ALL, "");
1070 
1071 	TAILQ_INIT(&eecmd_history.head);
1072 	TAILQ_INIT(&ir_history.head);
1073 	TAILQ_INIT(&lu_history.head);
1074 
1075 	ministate.line.type = LINE_TEXT;
1076 	ministate.vline.parent = &ministate.line;
1077 	ministate.buffer.current_line = &ministate.vline;
1078 
1079 	/* initialize help window */
1080 	TAILQ_INIT(&helpwin.head);
1081 
1082 	base_map = &global_map;
1083 	current_map = &global_map;
1084 
1085 	initscr();
1086 
1087 	if (enable_colors) {
1088 		if (has_colors()) {
1089 			start_color();
1090 			use_default_colors();
1091 		} else
1092 			enable_colors = 0;
1093 	}
1094 
1095 	config_apply_style();
1096 
1097 	raw();
1098 	noecho();
1099 	nonl();
1100 	intrflush(stdscr, FALSE);
1101 
1102 	if ((tabline = newwin(1, COLS, 0, 0)) == NULL)
1103 		return 0;
1104 	if ((body = newwin(LINES - 3, COLS, 1, 0)) == NULL)
1105 		return 0;
1106 	if ((modeline = newwin(1, COLS, LINES-2, 0)) == NULL)
1107 		return 0;
1108 	if ((echoarea = newwin(1, COLS, LINES-1, 0)) == NULL)
1109 		return 0;
1110 	if ((minibuffer = newwin(1, COLS, LINES-1, 0)) == NULL)
1111 		return 0;
1112 	if ((help = newwin(1, 1, 1, 0)) == NULL)
1113 		return 0;
1114 
1115 	body_lines = LINES-3;
1116 	body_cols = COLS;
1117 
1118 	wbkgd(body, body_face.body);
1119 	wbkgd(echoarea, minibuffer_face.background);
1120 
1121 	update_x_offset();
1122 
1123 	keypad(body, TRUE);
1124 	scrollok(body, FALSE);
1125 
1126 	/* non-blocking input */
1127 	wtimeout(body, 0);
1128 
1129 	mvwprintw(body, 0, 0, "");
1130 
1131 	event_set(&stdioev, 0, EV_READ | EV_PERSIST, dispatch_stdio, NULL);
1132 	event_add(&stdioev, NULL);
1133 
1134 	signal_set(&winchev, SIGWINCH, handle_resize, NULL);
1135 	signal_add(&winchev, NULL);
1136 
1137 	return 1;
1138 }
1139 
1140 void
1141 ui_on_tab_loaded(struct tab *tab)
1142 {
1143 	stop_loading_anim(tab);
1144 	message("Loaded %s", tab->hist_cur->h);
1145 
1146 	redraw_tabline();
1147 	wrefresh(tabline);
1148 	place_cursor(0);
1149 }
1150 
1151 void
1152 ui_on_tab_refresh(struct tab *tab)
1153 {
1154 	wrap_page(&tab->buffer, body_cols);
1155 	if (tab->flags & TAB_CURRENT)
1156 		redraw_tab(tab);
1157 	else
1158 		tab->flags |= TAB_URGENT;
1159 }
1160 
1161 const char *
1162 ui_keyname(int k)
1163 {
1164 	return keyname(k);
1165 }
1166 
1167 void
1168 ui_toggle_side_window(void)
1169 {
1170 	side_window = !side_window;
1171 	if (side_window)
1172 		recompute_help();
1173 
1174 	/*
1175 	 * ugly hack, but otherwise the window doesn't get updated
1176 	 * until I call handle_resize a second time (i.e. C-l).  I
1177 	 * will be happy to know why something like this is needed.
1178 	 */
1179 	handle_resize_nodelay(0, 0, NULL);
1180 	handle_resize_nodelay(0, 0, NULL);
1181 }
1182 
1183 void
1184 ui_schedule_redraw(void)
1185 {
1186 	handle_resize_nodelay(0, 0, NULL);
1187 }
1188 
1189 void
1190 ui_require_input(struct tab *tab, int hide)
1191 {
1192 	/* TODO: hard-switching to another tab is ugly */
1193 	switch_to_tab(tab);
1194 
1195 	enter_minibuffer(ir_self_insert, ir_select, exit_minibuffer,
1196 	    &ir_history, NULL, NULL);
1197 	strlcpy(ministate.prompt, "Input required: ",
1198 	    sizeof(ministate.prompt));
1199 	redraw_tab(tab);
1200 }
1201 
1202 void
1203 ui_yornp(const char *prompt, void (*fn)(int, struct tab *),
1204     struct tab *data)
1205 {
1206 	yornp(prompt, fn, data);
1207 	redraw_tab(current_tab());
1208 }
1209 
1210 void
1211 ui_read(const char *prompt, void (*fn)(const char*, struct tab *),
1212     struct tab *data)
1213 {
1214 	completing_read(prompt, fn, data, NULL, NULL);
1215 	redraw_tab(current_tab());
1216 }
1217 
1218 void
1219 ui_end(void)
1220 {
1221 	endwin();
1222 }