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Date:: Thu Jul 1 14:01:44 2021 UTC
Message:: handle the resize better Try to preserve as much as possible the current_line and top_line during wrap_page. In redraw_window recompute the correct y position.
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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 "telescope.h"
34 
35 #include <assert.h>
36 #include <curses.h>
37 #include <event.h>
38 #include <limits.h>
39 #include <locale.h>
40 #include <signal.h>
41 #include <stdarg.h>
42 #include <stdlib.h>
43 #include <string.h>
44 #include <unistd.h>
45 
46 static struct event	stdioev, winchev;
47 
48 static void		 global_key_unbound(void);
49 static void		 minibuffer_hist_save_entry(void);
50 static void		 minibuffer_self_insert(void);
51 static void		 yornp_self_insert(void);
52 static void		 yornp_abort(void);
53 static void		 read_self_insert(void);
54 static void		 read_abort(void);
55 static void		 read_select(void);
56 
57 static struct vline	*nth_line(struct buffer*, size_t);
58 static struct buffer	*current_buffer(void);
59 static int		 readkey(void);
60 static void		 dispatch_stdio(int, short, void*);
61 static void		 handle_clear_minibuf(int, short, void*);
62 static void		 handle_resize(int, short, void*);
63 static void		 handle_resize_nodelay(int, short, void*);
64 static int		 wrap_page(struct buffer*, int);
65 static void		 print_vline(int, int, WINDOW*, struct vline*);
66 static void		 redraw_tabline(void);
67 static void		 redraw_window(WINDOW*, int, int, struct buffer*);
68 static void		 redraw_help(void);
69 static void		 redraw_body(struct tab*);
70 static void		 redraw_modeline(struct tab*);
71 static void		 redraw_minibuffer(void);
72 static void		 redraw_tab(struct tab*);
73 static void		 emit_help_item(char*, void*);
74 static void		 rec_compute_help(struct kmap*, char*, size_t);
75 static void		 recompute_help(void);
76 static void		 update_loading_anim(int, short, void*);
77 static void		 stop_loading_anim(struct tab*);
78 static void		 session_new_tab_cb(const char*);
79 static void		 usage(void);
80 
81 static int		 x_offset;
82 
83 struct thiskey thiskey;
84 
85 static struct event	resizeev;
86 static struct timeval	resize_timer = { 0, 250000 };
87 
88 static WINDOW	*tabline, *body, *modeline, *minibuf;
89 
90 int			 body_lines, body_cols;
91 
92 static WINDOW		*help;
93 static struct buffer	 helpwin;
94 static int		 help_lines, help_cols;
95 
96 static int		 side_window;
97 
98 static struct event	clminibufev;
99 static struct timeval	clminibufev_timer = { 5, 0 };
100 static struct timeval	loadingev_timer = { 0, 250000 };
101 
102 static uint32_t		 tab_counter;
103 
104 static char	keybuf[64];
105 
106 static void (*yornp_cb)(int, unsigned int);
107 static unsigned int yornp_data;
108 
109 static void (*read_cb)(const char*, unsigned int);
110 static unsigned int read_data;
111 
112 struct kmap global_map,
113 	minibuffer_map,
114 	*current_map,
115 	*base_map;
116 
117 struct histhead eecmd_history,
118 	ir_history,
119 	lu_history,
120 	read_history;
121 
122 int in_minibuffer;
123 
124 struct ministate ministate;
125 
126 static inline void
127 update_x_offset(void)
128 {
129 	if (olivetti_mode && fill_column < body_cols)
130 		x_offset = (body_cols - fill_column)/2;
131 	else
132 		x_offset = 0;
133 }
134 
135 void
136 save_excursion(struct excursion *place, struct buffer *buffer)
137 {
138 	place->curs_x = buffer->curs_x;
139 	place->curs_y = buffer->curs_y;
140 	place->line_off = buffer->line_off;
141 	place->current_line = buffer->current_line;
142 	place->cpoff = buffer->cpoff;
143 }
144 
145 void
146 restore_excursion(struct excursion *place, struct buffer *buffer)
147 {
148 	buffer->curs_x = place->curs_x;
149 	buffer->curs_y = place->curs_y;
150 	buffer->line_off = place->line_off;
151 	buffer->current_line = place->current_line;
152 	buffer->cpoff = place->cpoff;
153 }
154 
155 void
156 restore_cursor(struct buffer *buffer)
157 {
158 	struct vline	*vl;
159 	const char	*prfx;
160 
161 	vl = buffer->current_line;
162 	if (vl == NULL || vl->line == NULL)
163 		buffer->curs_x = buffer->cpoff = 0;
164 	else
165 		buffer->curs_x = utf8_snwidth(vl->line, buffer->cpoff);
166 
167 	buffer->curs_x += x_offset;
168 
169 	if (vl != NULL) {
170 		prfx = line_prefixes[vl->parent->type].prfx1;
171 		buffer->curs_x += utf8_swidth(prfx);
172 	}
173 }
174 
175 static void
176 global_key_unbound(void)
177 {
178 	message("%s is undefined", keybuf);
179 }
180 
181 static void
182 minibuffer_hist_save_entry(void)
183 {
184 	struct hist	*hist;
185 
186 	if (ministate.history == NULL)
187 		return;
188 
189 	if ((hist = calloc(1, sizeof(*hist))) == NULL)
190 		abort();
191 
192 	strlcpy(hist->h, ministate.buf, sizeof(hist->h));
193 
194 	if (TAILQ_EMPTY(&ministate.history->head))
195 		TAILQ_INSERT_HEAD(&ministate.history->head, hist, entries);
196 	else
197 		TAILQ_INSERT_TAIL(&ministate.history->head, hist, entries);
198 	ministate.history->len++;
199 }
200 
201 /*
202  * taint the minibuffer cache: if we're currently showing a history
203  * element, copy that to the current buf and reset the "history
204  * navigation" thing.
205  */
206 void
207 minibuffer_taint_hist(void)
208 {
209 	if (ministate.hist_cur == NULL)
210 		return;
211 
212 	strlcpy(ministate.buf, ministate.hist_cur->h, sizeof(ministate.buf));
213 	ministate.hist_cur = NULL;
214 }
215 
216 static void
217 minibuffer_self_insert(void)
218 {
219 	char	*c, tmp[5] = {0};
220 	size_t	len;
221 
222 	minibuffer_taint_hist();
223 
224 	if (thiskey.cp == 0)
225 		return;
226 
227 	len = utf8_encode(thiskey.cp, tmp);
228 	c = utf8_nth(ministate.buffer.current_line->line, ministate.buffer.cpoff);
229 	if (c + len > ministate.buf + sizeof(ministate.buf) - 1)
230 		return;
231 
232 	memmove(c + len, c, strlen(c)+1);
233 	memcpy(c, tmp, len);
234 	ministate.buffer.cpoff++;
235 }
236 
237 void
238 eecmd_self_insert(void)
239 {
240 	if (thiskey.meta || unicode_isspace(thiskey.cp) ||
241 	    !unicode_isgraph(thiskey.cp)) {
242 		global_key_unbound();
243 		return;
244 	}
245 
246 	minibuffer_self_insert();
247 }
248 
249 void
250 eecmd_select(void)
251 {
252 	struct cmd *cmd;
253 
254 	for (cmd = cmds; cmd->cmd != NULL; ++cmd) {
255 		if (!strcmp(cmd->cmd, ministate.buf)) {
256 			exit_minibuffer();
257 			minibuffer_hist_save_entry();
258 			cmd->fn(current_buffer());
259 			return;
260 		}
261 	}
262 
263 	message("No match");
264 }
265 
266 void
267 ir_self_insert(void)
268 {
269 	minibuffer_self_insert();
270 }
271 
272 void
273 ir_select(void)
274 {
275 	char		 buf[1025] = {0};
276 	struct phos_uri	 uri;
277 	struct tab	*tab;
278 
279 	tab = current_tab();
280 
281 	exit_minibuffer();
282 	minibuffer_hist_save_entry();
283 
284 	/* a bit ugly but... */
285 	memcpy(&uri, &tab->uri, sizeof(tab->uri));
286 	phos_uri_set_query(&uri, ministate.buf);
287 	phos_serialize_uri(&uri, buf, sizeof(buf));
288 	load_url_in_tab(tab, buf);
289 }
290 
291 void
292 lu_self_insert(void)
293 {
294 	if (thiskey.meta || unicode_isspace(thiskey.key) ||
295 	    !unicode_isgraph(thiskey.key)) {
296 		global_key_unbound();
297 		return;
298 	}
299 
300 	minibuffer_self_insert();
301 }
302 
303 void
304 lu_select(void)
305 {
306 	exit_minibuffer();
307 	minibuffer_hist_save_entry();
308 	load_url_in_tab(current_tab(), ministate.buf);
309 }
310 
311 void
312 bp_select(void)
313 {
314 	exit_minibuffer();
315 	if (*ministate.buf != '\0')
316 		add_to_bookmarks(ministate.buf);
317 	else
318 		message("Abort.");
319 }
320 
321 static void
322 yornp_self_insert(void)
323 {
324 	if (thiskey.key != 'y' && thiskey.key != 'n') {
325 		message("Please answer y or n");
326 		return;
327 	}
328 
329 	exit_minibuffer();
330 	yornp_cb(thiskey.key == 'y', yornp_data);
331 }
332 
333 static void
334 yornp_abort(void)
335 {
336 	exit_minibuffer();
337 	yornp_cb(0, yornp_data);
338 }
339 
340 static void
341 read_self_insert(void)
342 {
343 	if (thiskey.meta || !unicode_isgraph(thiskey.cp)) {
344 		global_key_unbound();
345 		return;
346 	}
347 
348 	minibuffer_self_insert();
349 }
350 
351 static void
352 read_abort(void)
353 {
354 	exit_minibuffer();
355 	read_cb(NULL, read_data);
356 }
357 
358 static void
359 read_select(void)
360 {
361         exit_minibuffer();
362 	minibuffer_hist_save_entry();
363 	read_cb(ministate.buf, read_data);
364 }
365 
366 static struct vline *
367 nth_line(struct buffer *buffer, size_t n)
368 {
369 	struct vline	*vl;
370 	size_t		 i;
371 
372 	i = 0;
373 	TAILQ_FOREACH(vl, &buffer->head, vlines) {
374 		if (i == n)
375 			return vl;
376 		i++;
377 	}
378 
379 	/* unreachable */
380 	abort();
381 }
382 
383 struct tab *
384 current_tab(void)
385 {
386 	struct tab *t;
387 
388 	TAILQ_FOREACH(t, &tabshead, tabs) {
389 		if (t->flags & TAB_CURRENT)
390 			return t;
391 	}
392 
393 	/* unreachable */
394 	abort();
395 }
396 
397 struct buffer *
398 current_buffer(void)
399 {
400 	if (in_minibuffer)
401 		return &ministate.buffer;
402 	return &current_tab()->buffer;
403 }
404 
405 static int
406 readkey(void)
407 {
408 	uint32_t state = 0;
409 
410 	if ((thiskey.key = wgetch(body)) == ERR)
411 		return 0;
412 
413 	thiskey.meta = thiskey.key == 27;
414 	if (thiskey.meta) {
415 		thiskey.key = wgetch(body);
416 		if (thiskey.key == ERR || thiskey.key == 27) {
417 			thiskey.meta = 0;
418 			thiskey.key = 27;
419 		}
420 	}
421 
422 	thiskey.cp = 0;
423 	if ((unsigned int)thiskey.key < UINT8_MAX) {
424 		while (1) {
425 			if (!utf8_decode(&state, &thiskey.cp, (uint8_t)thiskey.key))
426 				break;
427 			if ((thiskey.key = wgetch(body)) == ERR) {
428 				message("Error decoding user input");
429 				return 0;
430 			}
431 		}
432 	}
433 
434 	return 1;
435 }
436 
437 static void
438 dispatch_stdio(int fd, short ev, void *d)
439 {
440 	struct keymap	*k;
441 	const char	*keyname;
442 	char		 tmp[5] = {0};
443 
444 	if (!readkey())
445 		return;
446 
447 	if (keybuf[0] != '\0')
448 		strlcat(keybuf, " ", sizeof(keybuf));
449 	if (thiskey.meta)
450 		strlcat(keybuf, "M-", sizeof(keybuf));
451 	if (thiskey.cp != 0) {
452 		utf8_encode(thiskey.cp, tmp);
453 		strlcat(keybuf, tmp, sizeof(keybuf));
454 	} else {
455 		if ((keyname = unkbd(thiskey.key)) != NULL)
456 			strlcat(keybuf, keyname, sizeof(keybuf));
457 		else {
458 			tmp[0] = thiskey.key;
459 			strlcat(keybuf, tmp, sizeof(keybuf));
460 		}
461 	}
462 
463 	TAILQ_FOREACH(k, &current_map->m, keymaps) {
464 		if (k->meta == thiskey.meta &&
465 		    k->key == thiskey.key) {
466 			if (k->fn == NULL)
467 				current_map = &k->map;
468 			else {
469 				current_map = base_map;
470 				strlcpy(keybuf, "", sizeof(keybuf));
471 				k->fn(current_buffer());
472 			}
473 			goto done;
474 		}
475 	}
476 
477 	if (current_map->unhandled_input != NULL)
478 		current_map->unhandled_input();
479 	else
480 		global_key_unbound();
481 
482 	strlcpy(keybuf, "", sizeof(keybuf));
483 	current_map = base_map;
484 
485 done:
486 	if (side_window)
487 		recompute_help();
488 
489 	redraw_tab(current_tab());
490 }
491 
492 static void
493 handle_clear_minibuf(int fd, short ev, void *d)
494 {
495 	free(ministate.curmesg);
496 	ministate.curmesg = NULL;
497 
498 	redraw_minibuffer();
499 	if (in_minibuffer) {
500 		wrefresh(body);
501 		wrefresh(minibuf);
502 	} else {
503 		wrefresh(minibuf);
504 		wrefresh(body);
505 	}
506 }
507 
508 static void
509 handle_resize(int sig, short ev, void *d)
510 {
511 	if (event_pending(&resizeev, EV_TIMEOUT, NULL)) {
512 		event_del(&resizeev);
513 	}
514 	evtimer_set(&resizeev, handle_resize_nodelay, NULL);
515 	evtimer_add(&resizeev, &resize_timer);
516 }
517 
518 static void
519 handle_resize_nodelay(int s, short ev, void *d)
520 {
521 	struct tab	*tab;
522 
523 	endwin();
524 	refresh();
525 	clear();
526 
527 	/* move and resize the windows, in reverse order! */
528 
529 	mvwin(minibuf, LINES-1, 0);
530 	wresize(minibuf, 1, COLS);
531 
532 	mvwin(modeline, LINES-2, 0);
533 	wresize(modeline, 1, COLS);
534 
535 	body_lines = LINES-3;
536 	body_cols = COLS;
537 
538 	if (side_window) {
539 		help_cols = 0.3 * COLS;
540 		help_lines = LINES-3;
541 		mvwin(help, 1, 0);
542 		wresize(help, help_lines, help_cols);
543 
544 		wrap_page(&helpwin, help_cols);
545 
546 		body_cols = COLS - help_cols - 1;
547 		mvwin(body, 1, help_cols);
548 	} else
549 		mvwin(body, 1, 0);
550 
551 	update_x_offset();
552 	wresize(body, body_lines, body_cols);
553 
554 	wresize(tabline, 1, COLS);
555 
556 	tab = current_tab();
557 
558 	wrap_page(&tab->buffer, body_cols);
559 	redraw_tab(tab);
560 }
561 
562 static int
563 wrap_page(struct buffer *buffer, int width)
564 {
565 	struct line		*l;
566 	const struct line	*top_orig, *orig;
567 	struct vline		*vl;
568 	int			 pre_width;
569 	const char		*prfx;
570 
571 	top_orig = buffer->top_line == NULL ? NULL : buffer->top_line->parent;
572 	orig = buffer->current_line == NULL ? NULL : buffer->current_line->parent;
573 
574 	buffer->top_line = NULL;
575 	buffer->current_line = NULL;
576 
577 	buffer->force_redraw = 1;
578 	buffer->curs_y = 0;
579 	buffer->line_off = 0;
580 
581 	empty_vlist(buffer);
582 
583 	TAILQ_FOREACH(l, &buffer->page.head, lines) {
584 		prfx = line_prefixes[l->type].prfx1;
585 		switch (l->type) {
586 		case LINE_TEXT:
587 		case LINE_LINK:
588 		case LINE_TITLE_1:
589 		case LINE_TITLE_2:
590 		case LINE_TITLE_3:
591 		case LINE_ITEM:
592 		case LINE_QUOTE:
593 		case LINE_PRE_START:
594 		case LINE_PRE_END:
595 			wrap_text(buffer, prfx, l, MIN(fill_column, width));
596 			break;
597 		case LINE_PRE_CONTENT:
598 			if (olivetti_mode)
599 				pre_width = MIN(fill_column, width);
600 			else
601 				pre_width = width;
602 			hardwrap_text(buffer, l, pre_width);
603 			break;
604 		}
605 
606 		if (top_orig == l && buffer->top_line == NULL) {
607 			buffer->line_off = buffer->line_max-1;
608 			buffer->top_line = TAILQ_LAST(&buffer->head, vhead);
609 
610 			while (1) {
611 				vl = TAILQ_PREV(buffer->top_line, vhead, vlines);
612 				if (vl == NULL || vl->parent != orig)
613 					break;
614 				buffer->top_line = vl;
615 				buffer->line_off--;
616 			}
617 		}
618 
619 		if (orig == l && buffer->current_line == NULL) {
620 			buffer->current_line = TAILQ_LAST(&buffer->head, vhead);
621 
622 			while (1) {
623 				vl = TAILQ_PREV(buffer->current_line, vhead, vlines);
624 				if (vl == NULL || vl->parent != orig)
625 					break;
626 				buffer->current_line = vl;
627 			}
628 		}
629 	}
630 
631         if (buffer->current_line == NULL)
632 		buffer->current_line = TAILQ_FIRST(&buffer->head);
633 
634 	if (buffer->top_line == NULL)
635 		buffer->top_line = buffer->current_line;
636 
637 	return 1;
638 }
639 
640 static void
641 print_vline(int off, int width, WINDOW *window, struct vline *vl)
642 {
643 	const char *text;
644 	const char *prfx;
645 	struct line_face *f;
646 	int i, left, x, y;
647 
648 	f = &line_faces[vl->parent->type];
649 
650 	/* unused, set by getyx */
651 	(void)y;
652 
653 	if (!vl->flags)
654 		prfx = line_prefixes[vl->parent->type].prfx1;
655 	else
656 		prfx = line_prefixes[vl->parent->type].prfx2;
657 
658 	text = vl->line;
659 	if (text == NULL)
660 		text = "";
661 
662 	wattr_on(window, body_face.left, NULL);
663 	for (i = 0; i < off; i++)
664 		waddch(window, ' ');
665 	wattr_off(window, body_face.left, NULL);
666 
667 	wattr_on(window, f->prefix, NULL);
668 	wprintw(window, "%s", prfx);
669 	wattr_off(window, f->prefix, NULL);
670 
671 	wattr_on(window, f->text, NULL);
672 	wprintw(window, "%s", text);
673 	wattr_off(window, f->text, NULL);
674 
675 	getyx(window, y, x);
676 
677 	left = width - x;
678 
679 	wattr_on(window, f->trail, NULL);
680 	for (i = 0; i < left - off - 1; ++i)
681 		waddch(window, ' ');
682 	wattr_off(window, f->trail, NULL);
683 
684 	wattr_on(window, body_face.right, NULL);
685 	for (i = 0; i < off; i++)
686 		waddch(window, ' ');
687 	wattr_off(window, body_face.right, NULL);
688 
689 }
690 
691 static void
692 redraw_tabline(void)
693 {
694 	struct tab	*tab;
695 	size_t		 toskip, ots, tabwidth, space, x;
696 	int		 current, y, truncated;
697 	const char	*title;
698 	char		 buf[25];
699 
700 	x = 0;
701 
702 	/* unused, but setted by a getyx */
703 	(void)y;
704 
705 	tabwidth = sizeof(buf)+1;
706 	space = COLS-2;
707 
708 	toskip = 0;
709 	TAILQ_FOREACH(tab, &tabshead, tabs) {
710 		toskip++;
711 		if (tab->flags & TAB_CURRENT)
712 			break;
713 	}
714 
715 	if (toskip * tabwidth < space)
716 		toskip = 0;
717 	else {
718 		ots = toskip;
719 		toskip--;
720                 while (toskip != 0 &&
721 		    (ots - toskip+1) * tabwidth < space)
722 			toskip--;
723 	}
724 
725 	werase(tabline);
726 	wattr_on(tabline, tab_face.background, NULL);
727 	wprintw(tabline, toskip == 0 ? " " : "<");
728 	wattr_off(tabline, tab_face.background, NULL);
729 
730 	truncated = 0;
731 	TAILQ_FOREACH(tab, &tabshead, tabs) {
732 		if (truncated)
733 			break;
734 		if (toskip != 0) {
735 			toskip--;
736 			continue;
737 		}
738 
739 		getyx(tabline, y, x);
740 		if (x + sizeof(buf)+2 >= (size_t)COLS)
741 			truncated = 1;
742 
743 		current = tab->flags & TAB_CURRENT;
744 
745 		if (*(title = tab->buffer.page.title) == '\0')
746 			title = tab->hist_cur->h;
747 
748 		if (tab->flags & TAB_URGENT)
749 			strlcpy(buf, "!", sizeof(buf));
750 		else
751 			strlcpy(buf, " ", sizeof(buf));
752 
753                 if (strlcat(buf, title, sizeof(buf)) >= sizeof(buf)) {
754 			/* truncation happens */
755 			strlcpy(&buf[sizeof(buf)-4], "...", 4);
756 		} else {
757 			/* pad with spaces */
758 			while (strlcat(buf, "    ", sizeof(buf)) < sizeof(buf))
759 				/* nop */ ;
760 		}
761 
762 		if (current)
763 			wattr_on(tabline, tab_face.current, NULL);
764 		else
765 			wattr_on(tabline, tab_face.tab, NULL);
766 
767 		wprintw(tabline, "%s", buf);
768 		if (TAILQ_NEXT(tab, tabs) != NULL)
769 			wprintw(tabline, " ");
770 
771 		if (current)
772 			wattr_off(tabline, tab_face.current, NULL);
773 		else
774 			wattr_off(tabline, tab_face.tab, NULL);
775 	}
776 
777 	wattr_on(tabline, tab_face.background, NULL);
778 	for (; x < (size_t)COLS; ++x)
779 		waddch(tabline, ' ');
780 	if (truncated)
781 		mvwprintw(tabline, 0, COLS-1, ">");
782 	wattr_off(tabline, tab_face.background, NULL);
783 }
784 
785 static void
786 redraw_window(WINDOW *win, int height, int width, struct buffer *buffer)
787 {
788         struct vline	*vl;
789 	int		 l, onscreen;
790 
791 	/*
792 	 * Don't bother redraw the body if nothing changed.  Cursor
793 	 * movements count as "nothing changed" if it hasn't produced
794 	 * a scroll.  Ensure that wmove is called though!
795 	 */
796 	if (!buffer->force_redraw &&
797 	    buffer->last_line_off == buffer->line_off)
798 		goto end;
799 
800 again:
801 	werase(win);
802 	buffer->curs_y = 0;
803 
804 	if (TAILQ_EMPTY(&buffer->head))
805 		goto end;
806 
807 	l = 0;
808 	onscreen = 0;
809 	for (vl = buffer->top_line; vl != NULL; vl = TAILQ_NEXT(vl, vlines)) {
810 		wmove(win, l, 0);
811 		print_vline(x_offset, width, win, vl);
812 
813 		if (vl == buffer->current_line)
814 			onscreen = 1;
815 
816 		if (!onscreen)
817 			buffer->curs_y++;
818 
819 		l++;
820 		if (l == height)
821 			break;
822 	}
823 
824 	if (!onscreen) {
825 		for (; vl != NULL; vl = TAILQ_NEXT(vl, vlines)) {
826 			if (vl == buffer->current_line)
827 				break;
828 			buffer->line_off++;
829 			buffer->top_line = TAILQ_NEXT(buffer->top_line, vlines);
830 		}
831 
832 		goto again;
833 	}
834 
835 	buffer->last_line_off = buffer->line_off;
836 	restore_cursor(buffer);
837 	buffer->force_redraw = 0;
838 end:
839 	wmove(win, buffer->curs_y, buffer->curs_x);
840 }
841 
842 static void
843 redraw_help(void)
844 {
845 	redraw_window(help, help_lines, help_cols, &helpwin);
846 }
847 
848 static void
849 redraw_body(struct tab *tab)
850 {
851 	static struct tab *last_tab;
852 
853 	if (last_tab != tab)
854 		tab->buffer.force_redraw =1;
855 	last_tab = tab;
856 
857 	redraw_window(body, body_lines, body_cols, &tab->buffer);
858 }
859 
860 static inline char
861 trust_status_char(enum trust_state ts)
862 {
863 	switch (ts) {
864 	case TS_UNKNOWN:	return 'u';
865 	case TS_UNTRUSTED:	return '!';
866 	case TS_TRUSTED:	return 'v';
867 	case TS_VERIFIED:	return 'V';
868 	default:		return 'X';
869 	}
870 }
871 
872 static void
873 redraw_modeline(struct tab *tab)
874 {
875 	double		 pct;
876 	int		 x, y, max_x, max_y;
877 	const char	*mode = tab->buffer.page.name;
878 	const char	*spin = "-\\|/";
879 
880 	werase(modeline);
881 	wattr_on(modeline, modeline_face.background, NULL);
882 	wmove(modeline, 0, 0);
883 
884 	wprintw(modeline, "-%c%c %s ",
885 	    spin[tab->loading_anim_step],
886 	    trust_status_char(tab->trust),
887 	    mode == NULL ? "(none)" : mode);
888 
889 	pct = (tab->buffer.line_off + tab->buffer.curs_y) * 100.0 / tab->buffer.line_max;
890 
891 	if (tab->buffer.line_max <= (size_t)body_lines)
892                 wprintw(modeline, "All ");
893 	else if (tab->buffer.line_off == 0)
894                 wprintw(modeline, "Top ");
895 	else if (tab->buffer.line_off + body_lines >= tab->buffer.line_max)
896 		wprintw(modeline, "Bottom ");
897 	else
898 		wprintw(modeline, "%.0f%% ", pct);
899 
900 	wprintw(modeline, "%d/%d %s ",
901 	    tab->buffer.line_off + tab->buffer.curs_y,
902 	    tab->buffer.line_max,
903 	    tab->hist_cur->h);
904 
905 	getyx(modeline, y, x);
906 	getmaxyx(modeline, max_y, max_x);
907 
908 	(void)y;
909 	(void)max_y;
910 
911 	for (; x < max_x; ++x)
912 		waddstr(modeline, "-");
913 
914 	wattr_off(modeline, modeline_face.background, NULL);
915 }
916 
917 static void
918 redraw_minibuffer(void)
919 {
920 	struct tab *tab;
921 	size_t off_y, off_x = 0;
922 	char *start = NULL, *c = NULL;
923 
924 	/* unused, but set by getyx */
925 	(void)off_y;
926 
927 	wattr_on(minibuf, minibuffer_face.background, NULL);
928 	werase(minibuf);
929 
930 	if (in_minibuffer) {
931 		mvwprintw(minibuf, 0, 0, "%s", ministate.prompt);
932 		if (ministate.hist_cur != NULL)
933 			wprintw(minibuf, "(%zu/%zu) ",
934 			    ministate.hist_off + 1,
935 			    ministate.history->len);
936 
937 		getyx(minibuf, off_y, off_x);
938 
939 		start = ministate.hist_cur != NULL
940 			? ministate.hist_cur->h
941 			: ministate.buf;
942 		c = utf8_nth(ministate.buffer.current_line->line,
943 		    ministate.buffer.cpoff);
944 		while (utf8_swidth_between(start, c) > (size_t)COLS/2) {
945 			start = utf8_next_cp(start);
946 		}
947 
948 		waddstr(minibuf, start);
949 	}
950 
951 	if (ministate.curmesg != NULL)
952                 wprintw(minibuf, in_minibuffer ? "  [%s]" : "%s",
953 		    ministate.curmesg);
954 
955 	if (!in_minibuffer && ministate.curmesg == NULL)
956 		waddstr(minibuf, keybuf);
957 
958 	/* If nothing else, show the URL at point */
959 	if (!in_minibuffer && ministate.curmesg == NULL && *keybuf == '\0') {
960 		tab = current_tab();
961 		if (tab->buffer.current_line != NULL &&
962 		    tab->buffer.current_line->parent->type == LINE_LINK)
963 			waddstr(minibuf, tab->buffer.current_line->parent->alt);
964 	}
965 
966 	if (in_minibuffer)
967 		wmove(minibuf, 0, off_x + utf8_swidth_between(start, c));
968 
969 	wattr_off(minibuf, minibuffer_face.background, NULL);
970 }
971 
972 static void
973 redraw_tab(struct tab *tab)
974 {
975 	if (side_window) {
976 		redraw_help();
977 		wnoutrefresh(help);
978 	}
979 
980 	restore_cursor(&tab->buffer);
981 
982 	redraw_tabline();
983 	redraw_body(tab);
984 	redraw_modeline(tab);
985 	redraw_minibuffer();
986 
987 	wnoutrefresh(tabline);
988 	wnoutrefresh(modeline);
989 
990 	if (in_minibuffer) {
991 		wnoutrefresh(body);
992 		wnoutrefresh(minibuf);
993 	} else {
994 		wnoutrefresh(minibuf);
995 		wnoutrefresh(body);
996 	}
997 
998 	doupdate();
999 }
1000 
1001 static void
1002 emit_help_item(char *prfx, void *fn)
1003 {
1004 	struct line	*l;
1005 	struct cmd	*cmd;
1006 
1007 	for (cmd = cmds; cmd->cmd != NULL; ++cmd) {
1008 		if (fn == cmd->fn)
1009 			break;
1010 	}
1011 	assert(cmd != NULL);
1012 
1013 	if ((l = calloc(1, sizeof(*l))) == NULL)
1014 		abort();
1015 
1016 	l->type = LINE_TEXT;
1017 	l->alt = NULL;
1018 
1019 	asprintf(&l->line, "%s %s", prfx, cmd->cmd);
1020 
1021 	if (TAILQ_EMPTY(&helpwin.page.head))
1022 		TAILQ_INSERT_HEAD(&helpwin.page.head, l, lines);
1023 	else
1024 		TAILQ_INSERT_TAIL(&helpwin.page.head, l, lines);
1025 }
1026 
1027 static void
1028 rec_compute_help(struct kmap *keymap, char *prfx, size_t len)
1029 {
1030 	struct keymap	*k;
1031 	char		 p[32];
1032 	const char	*kn;
1033 
1034 	TAILQ_FOREACH(k, &keymap->m, keymaps) {
1035 		strlcpy(p, prfx, sizeof(p));
1036 		if (*p != '\0')
1037 			strlcat(p, " ", sizeof(p));
1038 		if (k->meta)
1039 			strlcat(p, "M-", sizeof(p));
1040 		if ((kn = unkbd(k->key)) != NULL)
1041 			strlcat(p, kn, sizeof(p));
1042 		else
1043 			strlcat(p, keyname(k->key), sizeof(p));
1044 
1045 		if (k->fn == NULL)
1046 			rec_compute_help(&k->map, p, sizeof(p));
1047 		else
1048 			emit_help_item(p, k->fn);
1049 	}
1050 }
1051 
1052 static void
1053 recompute_help(void)
1054 {
1055 	char	p[32] = { 0 };
1056 
1057 	empty_vlist(&helpwin);
1058 	empty_linelist(&helpwin);
1059 	rec_compute_help(current_map, p, sizeof(p));
1060 	wrap_page(&helpwin, help_cols);
1061 }
1062 
1063 void
1064 vmessage(const char *fmt, va_list ap)
1065 {
1066 	if (evtimer_pending(&clminibufev, NULL))
1067 		evtimer_del(&clminibufev);
1068 
1069 	free(ministate.curmesg);
1070 	ministate.curmesg = NULL;
1071 
1072 	if (fmt != NULL) {
1073 		evtimer_set(&clminibufev, handle_clear_minibuf, NULL);
1074 		evtimer_add(&clminibufev, &clminibufev_timer);
1075 
1076 		/* TODO: what to do if the allocation fails here? */
1077 		if (vasprintf(&ministate.curmesg, fmt, ap) == -1)
1078 			ministate.curmesg = NULL;
1079 	}
1080 
1081 	redraw_minibuffer();
1082 	if (in_minibuffer) {
1083 		wrefresh(body);
1084 		wrefresh(minibuf);
1085 	} else {
1086 		wrefresh(minibuf);
1087 		wrefresh(body);
1088 	}
1089 }
1090 
1091 void
1092 message(const char *fmt, ...)
1093 {
1094 	va_list ap;
1095 
1096 	va_start(ap, fmt);
1097 	vmessage(fmt, ap);
1098 	va_end(ap);
1099 }
1100 
1101 void
1102 start_loading_anim(struct tab *tab)
1103 {
1104 	if (tab->loading_anim)
1105 		return;
1106 	tab->loading_anim = 1;
1107 	evtimer_set(&tab->loadingev, update_loading_anim, tab);
1108 	evtimer_add(&tab->loadingev, &loadingev_timer);
1109 }
1110 
1111 static void
1112 update_loading_anim(int fd, short ev, void *d)
1113 {
1114 	struct tab	*tab = d;
1115 
1116 	tab->loading_anim_step = (tab->loading_anim_step+1)%4;
1117 
1118 	if (tab->flags & TAB_CURRENT) {
1119 		redraw_modeline(tab);
1120 		wrefresh(modeline);
1121 		wrefresh(body);
1122 		if (in_minibuffer)
1123 			wrefresh(minibuf);
1124 	}
1125 
1126 	evtimer_add(&tab->loadingev, &loadingev_timer);
1127 }
1128 
1129 static void
1130 stop_loading_anim(struct tab *tab)
1131 {
1132 	if (!tab->loading_anim)
1133 		return;
1134 	evtimer_del(&tab->loadingev);
1135 	tab->loading_anim = 0;
1136 	tab->loading_anim_step = 0;
1137 
1138 	if (!(tab->flags & TAB_CURRENT))
1139 		return;
1140 
1141 	redraw_modeline(tab);
1142 
1143 	wrefresh(modeline);
1144 	wrefresh(body);
1145 	if (in_minibuffer)
1146 		wrefresh(minibuf);
1147 }
1148 
1149 void
1150 load_url_in_tab(struct tab *tab, const char *url)
1151 {
1152 	message("Loading %s...", url);
1153 	start_loading_anim(tab);
1154 	load_url(tab, url);
1155 
1156 	tab->buffer.curs_x = 0;
1157 	tab->buffer.curs_y = 0;
1158 	redraw_tab(tab);
1159 }
1160 
1161 void
1162 enter_minibuffer(void (*self_insert_fn)(void), void (*donefn)(void),
1163     void (*abortfn)(void), struct histhead *hist)
1164 {
1165 	in_minibuffer = 1;
1166 	base_map = &minibuffer_map;
1167 	current_map = &minibuffer_map;
1168 
1169 	base_map->unhandled_input = self_insert_fn;
1170 
1171 	ministate.donefn = donefn;
1172 	ministate.abortfn = abortfn;
1173 	memset(ministate.buf, 0, sizeof(ministate.buf));
1174 	ministate.buffer.current_line = &ministate.vline;
1175 	ministate.buffer.current_line->line = ministate.buf;
1176 	ministate.buffer.cpoff = 0;
1177 	strlcpy(ministate.buf, "", sizeof(ministate.prompt));
1178 
1179 	ministate.history = hist;
1180 	ministate.hist_cur = NULL;
1181 	ministate.hist_off = 0;
1182 }
1183 
1184 void
1185 exit_minibuffer(void)
1186 {
1187 	werase(minibuf);
1188 
1189 	in_minibuffer = 0;
1190 	base_map = &global_map;
1191 	current_map = &global_map;
1192 }
1193 
1194 void
1195 switch_to_tab(struct tab *tab)
1196 {
1197 	struct tab	*t;
1198 
1199 	TAILQ_FOREACH(t, &tabshead, tabs) {
1200 		t->flags &= ~TAB_CURRENT;
1201 	}
1202 
1203 	tab->flags |= TAB_CURRENT;
1204 	tab->flags &= ~TAB_URGENT;
1205 }
1206 
1207 unsigned int
1208 tab_new_id(void)
1209 {
1210 	return tab_counter++;
1211 }
1212 
1213 struct tab *
1214 new_tab(const char *url)
1215 {
1216 	struct tab	*tab;
1217 
1218 	if ((tab = calloc(1, sizeof(*tab))) == NULL) {
1219 		event_loopbreak();
1220 		return NULL;
1221 	}
1222 	tab->fd = -1;
1223 
1224 	TAILQ_INIT(&tab->hist.head);
1225 
1226 	TAILQ_INIT(&tab->buffer.head);
1227 
1228 	tab->id = tab_new_id();
1229 	switch_to_tab(tab);
1230 
1231 	if (TAILQ_EMPTY(&tabshead))
1232 		TAILQ_INSERT_HEAD(&tabshead, tab, tabs);
1233 	else
1234 		TAILQ_INSERT_TAIL(&tabshead, tab, tabs);
1235 
1236 	load_url_in_tab(tab, url);
1237 	return tab;
1238 }
1239 
1240 static void
1241 session_new_tab_cb(const char *url)
1242 {
1243 	new_tab(url);
1244 }
1245 
1246 static void
1247 usage(void)
1248 {
1249 	fprintf(stderr, "USAGE: %s [-hn] [-c config] [url]\n", getprogname());
1250 	fprintf(stderr, "version: " PACKAGE " " VERSION "\n");
1251 }
1252 
1253 int
1254 ui_init(int argc, char * const *argv)
1255 {
1256 	char path[PATH_MAX];
1257 	const char *url = NEW_TAB_URL;
1258 	int ch, configtest = 0, fonf = 0;
1259 
1260 	if (getenv("NO_COLOR") != NULL)
1261 		enable_colors = 0;
1262 
1263 	strlcpy(path, getenv("HOME"), sizeof(path));
1264 	strlcat(path, "/.telescope/config", sizeof(path));
1265 
1266 	while ((ch = getopt(argc, argv, "c:hn")) != -1) {
1267 		switch (ch) {
1268 		case 'c':
1269 			fonf = 1;
1270 			strlcpy(path, optarg, sizeof(path));
1271 			break;
1272 		case 'n':
1273 			configtest = 1;
1274 			break;
1275 		case 'h':
1276 			usage();
1277 			return 0;
1278 		default:
1279 			usage();
1280 			return 1;
1281 		}
1282 	}
1283 	argc -= optind;
1284 	argv += optind;
1285 
1286 	/* setup keys before reading the config */
1287 	TAILQ_INIT(&global_map.m);
1288 	global_map.unhandled_input = global_key_unbound;
1289 
1290 	TAILQ_INIT(&minibuffer_map.m);
1291 
1292 	config_init();
1293 	parseconfig(path, fonf);
1294 	if (configtest){
1295 		puts("config OK");
1296 		exit(0);
1297 	}
1298 
1299 	if (argc != 0)
1300 		url = argv[0];
1301 
1302 	setlocale(LC_ALL, "");
1303 
1304 	TAILQ_INIT(&eecmd_history.head);
1305 	TAILQ_INIT(&ir_history.head);
1306 	TAILQ_INIT(&lu_history.head);
1307 
1308 	ministate.line.type = LINE_TEXT;
1309 	ministate.vline.parent = &ministate.line;
1310 	ministate.buffer.current_line = &ministate.vline;
1311 
1312 	/* initialize help window */
1313 	TAILQ_INIT(&helpwin.head);
1314 
1315 	base_map = &global_map;
1316 	current_map = &global_map;
1317 
1318 	initscr();
1319 
1320 	if (enable_colors) {
1321 		if (has_colors()) {
1322 			start_color();
1323 			use_default_colors();
1324 		} else
1325 			enable_colors = 0;
1326 	}
1327 
1328 	config_apply_style();
1329 
1330 	raw();
1331 	noecho();
1332 	nonl();
1333 	intrflush(stdscr, FALSE);
1334 
1335 	if ((tabline = newwin(1, COLS, 0, 0)) == NULL)
1336 		return 0;
1337 	if ((body = newwin(LINES - 3, COLS, 1, 0)) == NULL)
1338 		return 0;
1339 	if ((modeline = newwin(1, COLS, LINES-2, 0)) == NULL)
1340 		return 0;
1341 	if ((minibuf = newwin(1, COLS, LINES-1, 0)) == NULL)
1342 		return 0;
1343 	if ((help = newwin(1, 1, 1, 0)) == NULL)
1344 		return 0;
1345 
1346 	body_lines = LINES-3;
1347 	body_cols = COLS;
1348 
1349 	wbkgd(body, body_face.body);
1350 	wbkgd(minibuf, minibuffer_face.background);
1351 
1352 	update_x_offset();
1353 
1354 	keypad(body, TRUE);
1355 	scrollok(body, FALSE);
1356 
1357 	/* non-blocking input */
1358 	wtimeout(body, 0);
1359 
1360 	mvwprintw(body, 0, 0, "");
1361 
1362 	event_set(&stdioev, 0, EV_READ | EV_PERSIST, dispatch_stdio, NULL);
1363 	event_add(&stdioev, NULL);
1364 
1365 	signal_set(&winchev, SIGWINCH, handle_resize, NULL);
1366 	signal_add(&winchev, NULL);
1367 
1368 	load_last_session(session_new_tab_cb);
1369 	if (strcmp(url, NEW_TAB_URL) || TAILQ_EMPTY(&tabshead))
1370 		new_tab(url);
1371 
1372 	return 1;
1373 }
1374 
1375 void
1376 ui_on_tab_loaded(struct tab *tab)
1377 {
1378 	stop_loading_anim(tab);
1379 	message("Loaded %s", tab->hist_cur->h);
1380 
1381 	redraw_tabline();
1382 	wrefresh(tabline);
1383 	if (in_minibuffer)
1384 		wrefresh(minibuf);
1385 	else
1386 		wrefresh(body);
1387 }
1388 
1389 void
1390 ui_on_tab_refresh(struct tab *tab)
1391 {
1392 	wrap_page(&tab->buffer, body_cols);
1393 	if (tab->flags & TAB_CURRENT) {
1394 		restore_cursor(&tab->buffer);
1395 		redraw_tab(tab);
1396 	} else
1397 		tab->flags |= TAB_URGENT;
1398 }
1399 
1400 const char *
1401 ui_keyname(int k)
1402 {
1403 	return keyname(k);
1404 }
1405 
1406 void
1407 ui_toggle_side_window(void)
1408 {
1409 	side_window = !side_window;
1410 	if (side_window)
1411 		recompute_help();
1412 
1413 	/*
1414 	 * ugly hack, but otherwise the window doesn't get updated
1415 	 * until I call handle_resize a second time (i.e. C-l).  I
1416 	 * will be happy to know why something like this is needed.
1417 	 */
1418 	handle_resize_nodelay(0, 0, NULL);
1419 	handle_resize_nodelay(0, 0, NULL);
1420 }
1421 
1422 void
1423 ui_schedule_redraw(void)
1424 {
1425 	handle_resize_nodelay(0, 0, NULL);
1426 }
1427 
1428 void
1429 ui_require_input(struct tab *tab, int hide)
1430 {
1431 	/* TODO: hard-switching to another tab is ugly */
1432 	switch_to_tab(tab);
1433 
1434 	enter_minibuffer(ir_self_insert, ir_select, exit_minibuffer,
1435 	    &ir_history);
1436 	strlcpy(ministate.prompt, "Input required: ",
1437 	    sizeof(ministate.prompt));
1438 	redraw_tab(tab);
1439 }
1440 
1441 void
1442 ui_yornp(const char *prompt, void (*fn)(int, unsigned int),
1443     unsigned int data)
1444 {
1445 	size_t len;
1446 
1447 	if (in_minibuffer) {
1448 		fn(0, data);
1449 		return;
1450 	}
1451 
1452 	yornp_cb = fn;
1453 	yornp_data = data;
1454 	enter_minibuffer(yornp_self_insert, yornp_self_insert,
1455 	    yornp_abort, NULL);
1456 
1457 	len = sizeof(ministate.prompt);
1458 	strlcpy(ministate.prompt, prompt, len);
1459 	strlcat(ministate.prompt, " (y or n) ", len);
1460 	redraw_tab(current_tab());
1461 }
1462 
1463 void
1464 ui_read(const char *prompt, void (*fn)(const char*, unsigned int),
1465     unsigned int data)
1466 {
1467 	size_t len;
1468 
1469 	if (in_minibuffer)
1470 		return;
1471 
1472 	read_cb = fn;
1473 	read_data = data;
1474 	enter_minibuffer(read_self_insert, read_select, read_abort,
1475 	    &read_history);
1476 
1477 	len = sizeof(ministate.prompt);
1478 	strlcpy(ministate.prompt, prompt, len);
1479 	strlcat(ministate.prompt, ": ", len);
1480 	redraw_tab(current_tab());
1481 }
1482 
1483 void
1484 ui_end(void)
1485 {
1486 	endwin();
1487 }