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Date:: Sun Jul 18 13:10:21 2021 UTC
Message:: keep the scrolling during a save-excursion
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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 int		 readkey(void);
54 static void		 dispatch_stdio(int, short, void*);
55 static void		 handle_clear_echoarea(int, short, void*);
56 static void		 handle_resize(int, short, void*);
57 static void		 handle_resize_nodelay(int, short, void*);
58 static void		 rearrange_windows(void);
59 static int		 wrap_page(struct buffer*, int);
60 static void		 line_prefix_and_text(struct vline *, char *, size_t, const char **, const char **);
61 static void		 print_vline(int, int, WINDOW*, struct vline*);
62 static void		 redraw_tabline(void);
63 static void		 redraw_window(WINDOW*, int, int, int, struct buffer*);
64 static void		 redraw_help(void);
65 static void		 redraw_body(struct tab*);
66 static void		 redraw_modeline(struct tab*);
67 static void		 redraw_minibuffer(void);
68 static void		 do_redraw_echoarea(void);
69 static void		 do_redraw_minibuffer(void);
70 static void		 do_redraw_minibuffer_compl(void);
71 static void		 place_cursor(int);
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 
79 /*
80  * Used to know when we're finished loading.
81  */
82 static int		 operating;
83 
84 static int		 should_rearrange_windows;
85 static int		 too_small;
86 static int		 x_offset;
87 
88 struct thiskey	 thiskey;
89 struct tab	*current_tab;
90 
91 static struct event	resizeev;
92 static struct timeval	resize_timer = { 0, 250000 };
93 
94 static WINDOW	*tabline, *body, *modeline, *echoarea, *minibuffer;
95 
96 int			 body_lines, body_cols;
97 
98 static WINDOW		*help;
99 static struct buffer	 helpwin;
100 static int		 help_lines, help_cols;
101 
102 static int		 side_window;
103 
104 static struct event	clechoev;
105 static struct timeval	clechoev_timer = { 5, 0 };
106 static struct timeval	loadingev_timer = { 0, 250000 };
107 
108 static uint32_t		 tab_counter;
109 
110 static char	keybuf[64];
111 
112 struct kmap global_map,
113 	minibuffer_map,
114 	*current_map,
115 	*base_map;
116 
117 int in_minibuffer;
118 
119 static inline void
120 update_x_offset(void)
121 {
122 	if (olivetti_mode && fill_column < body_cols)
123 		x_offset = (body_cols - fill_column)/2;
124 	else
125 		x_offset = 0;
126 }
127 
128 void
129 save_excursion(struct excursion *place, struct buffer *buffer)
130 {
131 	place->curs_x = buffer->curs_x;
132 	place->curs_y = buffer->curs_y;
133 	place->line_off = buffer->line_off;
134 	place->top_line = buffer->top_line;
135 	place->current_line = buffer->current_line;
136 	place->cpoff = buffer->cpoff;
137 }
138 
139 void
140 restore_excursion(struct excursion *place, struct buffer *buffer)
141 {
142 	buffer->curs_x = place->curs_x;
143 	buffer->curs_y = place->curs_y;
144 	buffer->line_off = place->line_off;
145 	buffer->top_line = place->top_line;
146 	buffer->current_line = place->current_line;
147 	buffer->cpoff = place->cpoff;
148 }
149 
150 static void
151 restore_curs_x(struct buffer *buffer)
152 {
153 	struct vline	*vl;
154 	const char	*prfx;
155 
156 	vl = buffer->current_line;
157 	if (vl == NULL || vl->line == NULL)
158 		buffer->curs_x = buffer->cpoff = 0;
159 	else if (vl->parent->data != NULL)
160 		buffer->curs_x = utf8_snwidth(vl->parent->data+1, buffer->cpoff) + 1;
161 	else
162 		buffer->curs_x = utf8_snwidth(vl->line, buffer->cpoff);
163 
164 	buffer->curs_x += x_offset;
165 
166 	if (vl == NULL)
167 		return;
168 
169 	if (vl->parent->data != NULL)
170 		buffer->curs_x += utf8_swidth_between(vl->parent->line, vl->parent->data);
171 	else {
172 		prfx = line_prefixes[vl->parent->type].prfx1;
173 		buffer->curs_x += utf8_swidth(prfx);
174 	}
175 }
176 
177 void
178 global_key_unbound(void)
179 {
180 	message("%s is undefined", keybuf);
181 }
182 
183 struct buffer *
184 current_buffer(void)
185 {
186 	if (in_minibuffer)
187 		return &ministate.buffer;
188 	return &current_tab->buffer;
189 }
190 
191 static int
192 readkey(void)
193 {
194 	uint32_t state = 0;
195 
196 	if ((thiskey.key = wgetch(body)) == ERR)
197 		return 0;
198 
199 	thiskey.meta = thiskey.key == 27;
200 	if (thiskey.meta) {
201 		thiskey.key = wgetch(body);
202 		if (thiskey.key == ERR || thiskey.key == 27) {
203 			thiskey.meta = 0;
204 			thiskey.key = 27;
205 		}
206 	}
207 
208 	thiskey.cp = 0;
209 	if ((unsigned int)thiskey.key < UINT8_MAX) {
210 		while (1) {
211 			if (!utf8_decode(&state, &thiskey.cp, (uint8_t)thiskey.key))
212 				break;
213 			if ((thiskey.key = wgetch(body)) == ERR) {
214 				message("Error decoding user input");
215 				return 0;
216 			}
217 		}
218 	}
219 
220 	return 1;
221 }
222 
223 static void
224 dispatch_stdio(int fd, short ev, void *d)
225 {
226 	struct keymap	*k;
227 	const char	*keyname;
228 	char		 tmp[5] = {0};
229 
230 	/* TODO: schedule a redraw? */
231 	if (too_small)
232 		return;
233 
234 	if (!readkey())
235 		return;
236 
237 	if (keybuf[0] != '\0')
238 		strlcat(keybuf, " ", sizeof(keybuf));
239 	if (thiskey.meta)
240 		strlcat(keybuf, "M-", sizeof(keybuf));
241 	if (thiskey.cp != 0) {
242 		utf8_encode(thiskey.cp, tmp);
243 		strlcat(keybuf, tmp, sizeof(keybuf));
244 	} else if ((keyname = unkbd(thiskey.key)) != NULL) {
245 		strlcat(keybuf, keyname, sizeof(keybuf));
246 	} else {
247 		tmp[0] = thiskey.key;
248 		strlcat(keybuf, tmp, sizeof(keybuf));
249 	}
250 
251 	TAILQ_FOREACH(k, &current_map->m, keymaps) {
252 		if (k->meta == thiskey.meta &&
253 		    k->key == thiskey.key) {
254 			if (k->fn == NULL)
255 				current_map = &k->map;
256 			else {
257 				current_map = base_map;
258 				strlcpy(keybuf, "", sizeof(keybuf));
259 				k->fn(current_buffer());
260 			}
261 			goto done;
262 		}
263 	}
264 
265 	if (current_map->unhandled_input != NULL)
266 		current_map->unhandled_input();
267 	else
268 		global_key_unbound();
269 
270 	strlcpy(keybuf, "", sizeof(keybuf));
271 	current_map = base_map;
272 
273 done:
274 	if (side_window)
275 		recompute_help();
276 
277 	if (should_rearrange_windows)
278 		rearrange_windows();
279 	redraw_tab(current_tab);
280 }
281 
282 static void
283 handle_clear_echoarea(int fd, short ev, void *d)
284 {
285 	free(ministate.curmesg);
286 	ministate.curmesg = NULL;
287 
288 	redraw_minibuffer();
289 	place_cursor(0);
290 }
291 
292 static void
293 handle_resize(int sig, short ev, void *d)
294 {
295 	if (event_pending(&resizeev, EV_TIMEOUT, NULL)) {
296 		event_del(&resizeev);
297 	}
298 	evtimer_set(&resizeev, handle_resize_nodelay, NULL);
299 	evtimer_add(&resizeev, &resize_timer);
300 }
301 
302 static void
303 handle_resize_nodelay(int s, short ev, void *d)
304 {
305 	endwin();
306 	refresh();
307 	clear();
308 
309 	rearrange_windows();
310 }
311 
312 static void
313 rearrange_windows(void)
314 {
315 	int		 lines;
316 
317 	should_rearrange_windows = 0;
318 
319 	lines = LINES;
320 
321 	if ((too_small = lines < 15)) {
322 		erase();
323 		printw("Window too small.");
324 		refresh();
325 		return;
326 	}
327 
328 	/* move and resize the windows, in reverse order! */
329 
330 	if (in_minibuffer == MB_COMPREAD) {
331 		mvwin(minibuffer, lines-10, 0);
332 		wresize(minibuffer, 10, COLS);
333 		lines -= 10;
334 
335 		wrap_page(&ministate.compl.buffer, COLS);
336 	}
337 
338 	mvwin(echoarea, --lines, 0);
339 	wresize(echoarea, 1, COLS);
340 
341 	mvwin(modeline, --lines, 0);
342 	wresize(modeline, 1, COLS);
343 
344 	body_lines = --lines;
345 	body_cols = COLS;
346 
347 	if (side_window) {
348 		help_cols = 0.3 * COLS;
349 		help_lines = lines;
350 		mvwin(help, 1, 0);
351 		wresize(help, help_lines, help_cols);
352 
353 		wrap_page(&helpwin, help_cols);
354 
355 		body_cols = COLS - help_cols - 1;
356 		mvwin(body, 1, help_cols);
357 	} else
358 		mvwin(body, 1, 0);
359 
360 	update_x_offset();
361 	wresize(body, body_lines, body_cols);
362 
363 	wresize(tabline, 1, COLS);
364 
365 	wrap_page(&current_tab->buffer, body_cols);
366 	redraw_tab(current_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 		case LINE_COMPL:
412 		case LINE_COMPL_CURRENT:
413 			wrap_one(buffer, prfx, l, width);
414 			break;
415 		}
416 
417 		if (top_orig == l && buffer->top_line == NULL) {
418 			buffer->line_off = buffer->line_max-1;
419 			buffer->top_line = TAILQ_LAST(&buffer->head, vhead);
420 
421 			while (1) {
422 				vl = TAILQ_PREV(buffer->top_line, vhead, vlines);
423 				if (vl == NULL || vl->parent != orig)
424 					break;
425 				buffer->top_line = vl;
426 				buffer->line_off--;
427 			}
428 		}
429 
430 		if (orig == l && buffer->current_line == NULL) {
431 			buffer->current_line = TAILQ_LAST(&buffer->head, vhead);
432 
433 			while (1) {
434 				vl = TAILQ_PREV(buffer->current_line, vhead, vlines);
435 				if (vl == NULL || vl->parent != orig)
436 					break;
437 				buffer->current_line = vl;
438 			}
439 		}
440 	}
441 
442         if (buffer->current_line == NULL)
443 		buffer->current_line = TAILQ_FIRST(&buffer->head);
444 
445 	if (buffer->top_line == NULL)
446 		buffer->top_line = buffer->current_line;
447 
448 	return 1;
449 }
450 
451 static void
452 line_prefix_and_text(struct vline *vl, char *buf, size_t len,
453     const char **prfx_ret, const char **text_ret)
454 {
455 	int type, i, cont, width;
456 	char *space, *t;
457 
458 	if ((*text_ret = vl->line) == NULL)
459 		*text_ret = "";
460 
461 	cont = vl->flags & L_CONTINUATION;
462 	type = vl->parent->type;
463 	if (!cont)
464 		*prfx_ret = line_prefixes[type].prfx1;
465 	else
466 		*prfx_ret = line_prefixes[type].prfx2;
467 
468 	space = vl->parent->data;
469 	if (!emojify_link || type != LINE_LINK || space == NULL)
470 		return;
471 
472 	if (cont) {
473 		memset(buf, 0, len);
474 		width = utf8_swidth_between(vl->parent->line, space);
475 		for (i = 0; i < width + 1; ++i)
476 			strlcat(buf, " ", len);
477 	} else {
478 		strlcpy(buf, *text_ret, len);
479 		if ((t = strchr(buf, ' ')) != NULL)
480 			*t = '\0';
481 		strlcat(buf, " ", len);
482 
483 		/* skip the emoji */
484                 *text_ret += (space - vl->parent->line) + 1;
485 	}
486 
487 	*prfx_ret = buf;
488 }
489 
490 static inline void
491 print_vline_descr(int width, WINDOW *window, struct vline *vl)
492 {
493 	int x, y, goal;
494 
495 	if (vl->parent->type != LINE_COMPL &&
496 	    vl->parent->type != LINE_COMPL_CURRENT)
497 		return;
498 
499 	if (vl->parent->alt == NULL)
500 		return;
501 
502 	(void)y;
503 	getyx(window, y, x);
504 
505 	goal = width/2;
506 	if (goal <= x)
507 		wprintw(window, " ");
508 	for (; goal > x; ++x)
509 		wprintw(window, " ");
510 
511 	wprintw(window, "%s", vl->parent->alt);
512 }
513 
514 /*
515  * Core part of the rendering.  It prints a vline starting from the
516  * current cursor position.  Printing a vline consists of skipping
517  * `off' columns (for olivetti-mode), print the correct prefix (which
518  * may be the emoji in case of emojified links-lines), printing the
519  * text itself, filling until width - off and filling off columns
520  * again.
521  */
522 static void
523 print_vline(int off, int width, WINDOW *window, struct vline *vl)
524 {
525 	/*
526 	 * Believe me or not, I've seen emoji ten code points long!
527 	 * That means, to stay large, 4*10 bytes + NUL.
528 	 */
529 	char emojibuf[41] = {0};
530 	const char *text, *prfx;
531 	struct line_face *f;
532 	int i, left, x, y;
533 
534 	f = &line_faces[vl->parent->type];
535 
536 	/* unused, set by getyx */
537 	(void)y;
538 
539 	line_prefix_and_text(vl, emojibuf, sizeof(emojibuf), &prfx, &text);
540 
541 	wattr_on(window, body_face.left, NULL);
542 	for (i = 0; i < off; i++)
543 		waddch(window, ' ');
544 	wattr_off(window, body_face.left, NULL);
545 
546 	wattr_on(window, f->prefix, NULL);
547 	wprintw(window, "%s", prfx);
548 	wattr_off(window, f->prefix, NULL);
549 
550 	wattr_on(window, f->text, NULL);
551 	wprintw(window, "%s", text);
552 	print_vline_descr(width, window, vl);
553 	wattr_off(window, f->text, NULL);
554 
555 	getyx(window, y, x);
556 
557 	left = width - x;
558 
559 	wattr_on(window, f->trail, NULL);
560 	for (i = 0; i < left - off; ++i)
561 		waddch(window, ' ');
562 	wattr_off(window, f->trail, NULL);
563 
564 	wattr_on(window, body_face.right, NULL);
565 	for (i = 0; i < off; i++)
566 		waddch(window, ' ');
567 	wattr_off(window, body_face.right, NULL);
568 
569 }
570 
571 static void
572 redraw_tabline(void)
573 {
574 	struct tab	*tab;
575 	size_t		 toskip, ots, tabwidth, space, x;
576 	int		 current, y, truncated, pair;
577 	const char	*title;
578 	char		 buf[25];
579 
580 	x = 0;
581 
582 	/* unused, but setted by a getyx */
583 	(void)y;
584 
585 	tabwidth = sizeof(buf)+1;
586 	space = COLS-2;
587 
588 	toskip = 0;
589 	TAILQ_FOREACH(tab, &tabshead, tabs) {
590 		toskip++;
591 		if (tab == current_tab)
592 			break;
593 	}
594 
595 	if (toskip * tabwidth < space)
596 		toskip = 0;
597 	else {
598 		ots = toskip;
599 		toskip--;
600                 while (toskip != 0 &&
601 		    (ots - toskip+1) * tabwidth < space)
602 			toskip--;
603 	}
604 
605 	werase(tabline);
606 	wattr_on(tabline, tab_face.background, NULL);
607 	wprintw(tabline, toskip == 0 ? " " : "<");
608 	wattr_off(tabline, tab_face.background, NULL);
609 
610 	truncated = 0;
611 	TAILQ_FOREACH(tab, &tabshead, tabs) {
612 		if (truncated)
613 			break;
614 		if (toskip != 0) {
615 			toskip--;
616 			continue;
617 		}
618 
619 		getyx(tabline, y, x);
620 		if (x + sizeof(buf)+2 >= (size_t)COLS)
621 			truncated = 1;
622 
623 		current = tab == current_tab;
624 
625 		if (*(title = tab->buffer.page.title) == '\0')
626 			title = tab->hist_cur->h;
627 
628 		if (tab->flags & TAB_URGENT)
629 			strlcpy(buf, "!", sizeof(buf));
630 		else
631 			strlcpy(buf, " ", sizeof(buf));
632 
633                 if (strlcat(buf, title, sizeof(buf)) >= sizeof(buf)) {
634 			/* truncation happens */
635 			strlcpy(&buf[sizeof(buf)-4], "...", 4);
636 		} else {
637 			/* pad with spaces */
638 			while (strlcat(buf, "    ", sizeof(buf)) < sizeof(buf))
639 				/* nop */ ;
640 		}
641 
642 		pair = current ? tab_face.current : tab_face.tab;
643 		wattr_on(tabline, pair, NULL);
644 		wprintw(tabline, "%s", buf);
645 		wattr_off(tabline, pair, NULL);
646 
647 		wattr_on(tabline, tab_face.background, NULL);
648 		if (TAILQ_NEXT(tab, tabs) != NULL)
649 			wprintw(tabline, "│");
650 		wattr_off(tabline, tab_face.background, NULL);
651 	}
652 
653 	wattr_on(tabline, tab_face.background, NULL);
654 	for (; x < (size_t)COLS; ++x)
655 		waddch(tabline, ' ');
656 	if (truncated)
657 		mvwprintw(tabline, 0, COLS-1, ">");
658 	wattr_off(tabline, tab_face.background, NULL);
659 }
660 
661 /*
662  * Compute the first visible line around vl.  Try to search forward
663  * until the end of the buffer; if a visible line is not found, search
664  * backward.  Return NULL if no viable line was found.
665  */
666 struct vline *
667 adjust_line(struct vline *vl, struct buffer *buffer)
668 {
669 	struct vline *t;
670 
671 	if (vl == NULL)
672 		return NULL;
673 
674 	if (!(vl->parent->flags & L_HIDDEN))
675 		return vl;
676 
677 	/* search forward */
678 	for (t = vl;
679 	     t != NULL && t->parent->flags & L_HIDDEN;
680 	     t = TAILQ_NEXT(t, vlines))
681 		;		/* nop */
682 
683 	if (t != NULL)
684 		return t;
685 
686 	/* search backward */
687 	for (t = vl;
688 	     t != NULL && t->parent->flags & L_HIDDEN;
689 	     t = TAILQ_PREV(t, vhead, vlines))
690 		;		/* nop */
691 
692 	return t;
693 }
694 
695 static void
696 redraw_window(WINDOW *win, int off, int height, int width, struct buffer *buffer)
697 {
698         struct vline	*vl;
699 	int		 l, onscreen;
700 
701 	restore_curs_x(buffer);
702 
703 	/*
704 	 * TODO: ignoring buffer->force_update and always
705 	 * re-rendering.  In theory we can recompute the y position
706 	 * without a re-render, and optimize here.  It's not the only
707 	 * optimisation possible here, wscrl wolud also be an
708 	 * interesting one.
709 	 */
710 
711 again:
712 	werase(win);
713 	buffer->curs_y = 0;
714 
715 	if (TAILQ_EMPTY(&buffer->head))
716 		goto end;
717 
718 	if (buffer->top_line == NULL)
719 		buffer->top_line = TAILQ_FIRST(&buffer->head);
720 
721 	buffer->top_line = adjust_line(buffer->top_line, buffer);
722 	if (buffer->top_line == NULL)
723 		goto end;
724 
725 	buffer->current_line = adjust_line(buffer->current_line, buffer);
726 
727 	l = 0;
728 	onscreen = 0;
729 	for (vl = buffer->top_line; vl != NULL; vl = TAILQ_NEXT(vl, vlines)) {
730 		if (vl->parent->flags & L_HIDDEN)
731 			continue;
732 
733 		wmove(win, l, 0);
734 		print_vline(off, width, win, vl);
735 
736 		if (vl == buffer->current_line)
737 			onscreen = 1;
738 
739 		if (!onscreen)
740 			buffer->curs_y++;
741 
742 		l++;
743 		if (l == height)
744 			break;
745 	}
746 
747 	if (!onscreen) {
748 		for (; vl != NULL; vl = TAILQ_NEXT(vl, vlines)) {
749 			if (vl == buffer->current_line)
750 				break;
751 			if (vl->parent->flags & L_HIDDEN)
752 				continue;
753 			buffer->line_off++;
754 			buffer->top_line = TAILQ_NEXT(buffer->top_line, vlines);
755 		}
756 
757 		if (vl != NULL)
758 			goto again;
759 	}
760 
761 	buffer->last_line_off = buffer->line_off;
762 	buffer->force_redraw = 0;
763 end:
764 	wmove(win, buffer->curs_y, buffer->curs_x);
765 }
766 
767 static void
768 redraw_help(void)
769 {
770 	redraw_window(help, 0, help_lines, help_cols, &helpwin);
771 }
772 
773 static void
774 redraw_body(struct tab *tab)
775 {
776 	static struct tab *last_tab;
777 
778 	if (last_tab != tab)
779 		tab->buffer.force_redraw =1;
780 	last_tab = tab;
781 
782 	redraw_window(body, x_offset, body_lines, body_cols, &tab->buffer);
783 }
784 
785 static inline char
786 trust_status_char(enum trust_state ts)
787 {
788 	switch (ts) {
789 	case TS_UNKNOWN:	return 'u';
790 	case TS_UNTRUSTED:	return '!';
791 	case TS_TEMP_TRUSTED:	return '!';
792 	case TS_TRUSTED:	return 'v';
793 	case TS_VERIFIED:	return 'V';
794 	default:		return 'X';
795 	}
796 }
797 
798 static void
799 redraw_modeline(struct tab *tab)
800 {
801 	double		 pct;
802 	int		 x, y, max_x, max_y;
803 	const char	*mode = tab->buffer.page.name;
804 	const char	*spin = "-\\|/";
805 
806 	werase(modeline);
807 	wattr_on(modeline, modeline_face.background, NULL);
808 	wmove(modeline, 0, 0);
809 
810 	wprintw(modeline, "-%c%c %s ",
811 	    spin[tab->loading_anim_step],
812 	    trust_status_char(tab->trust),
813 	    mode == NULL ? "(none)" : mode);
814 
815 	pct = (tab->buffer.line_off + tab->buffer.curs_y) * 100.0
816 		/ tab->buffer.line_max;
817 
818 	if (tab->buffer.line_max <= (size_t)body_lines)
819                 wprintw(modeline, "All ");
820 	else if (tab->buffer.line_off == 0)
821                 wprintw(modeline, "Top ");
822 	else if (tab->buffer.line_off + body_lines >= tab->buffer.line_max)
823 		wprintw(modeline, "Bottom ");
824 	else
825 		wprintw(modeline, "%.0f%% ", pct);
826 
827 	wprintw(modeline, "%d/%d %s ",
828 	    tab->buffer.line_off + tab->buffer.curs_y,
829 	    tab->buffer.line_max,
830 	    tab->hist_cur->h);
831 
832 	getyx(modeline, y, x);
833 	getmaxyx(modeline, max_y, max_x);
834 
835 	(void)y;
836 	(void)max_y;
837 
838 	for (; x < max_x; ++x)
839 		waddstr(modeline, "-");
840 
841 	wattr_off(modeline, modeline_face.background, NULL);
842 }
843 
844 static void
845 redraw_minibuffer(void)
846 {
847 	wattr_on(echoarea, minibuffer_face.background, NULL);
848 	werase(echoarea);
849 
850 	if (in_minibuffer)
851 		do_redraw_minibuffer();
852 	else
853 		do_redraw_echoarea();
854 
855 	if (in_minibuffer == MB_COMPREAD)
856 		do_redraw_minibuffer_compl();
857 
858 	wattr_off(echoarea, minibuffer_face.background, NULL);
859 }
860 
861 static void
862 do_redraw_echoarea(void)
863 {
864 	struct vline *vl;
865 
866 	if (ministate.curmesg != NULL)
867                 wprintw(echoarea, "%s", ministate.curmesg);
868 	else if (*keybuf != '\0')
869 		waddstr(echoarea, keybuf);
870 	else {
871 		/* If nothing else, show the URL at point */
872 		vl = current_tab->buffer.current_line;
873 		if (vl != NULL && vl->parent->type == LINE_LINK)
874 			waddstr(echoarea, vl->parent->alt);
875 	}
876 }
877 
878 static void
879 do_redraw_minibuffer(void)
880 {
881 	size_t		 off_y, off_x = 0;
882 	const char	*start, *c;
883 
884 	/* unused, set by getyx */
885 	(void)off_y;
886 
887 	wmove(echoarea, 0, 0);
888 
889 	if (in_minibuffer == MB_COMPREAD)
890 		wprintw(echoarea, "(%2d) ",
891 		    ministate.compl.buffer.line_max);
892 
893 	wprintw(echoarea, "%s", ministate.prompt);
894 	if (ministate.hist_cur != NULL)
895 		wprintw(echoarea, "(%zu/%zu) ",
896 		    ministate.hist_off + 1,
897 		    ministate.history->len);
898 
899 	getyx(echoarea, off_y, off_x);
900 
901 	start = ministate.hist_cur != NULL
902 		? ministate.hist_cur->h
903 		: ministate.buf;
904 	c = utf8_nth(ministate.buffer.current_line->line,
905 	    ministate.buffer.cpoff);
906 	while (utf8_swidth_between(start, c) > (size_t)COLS/2) {
907 		start = utf8_next_cp(start);
908 	}
909 
910 	waddstr(echoarea, start);
911 
912 	if (ministate.curmesg != NULL)
913 		wprintw(echoarea, " [%s]", ministate.curmesg);
914 
915 	wmove(echoarea, 0, off_x + utf8_swidth_between(start, c));
916 }
917 
918 static void
919 do_redraw_minibuffer_compl(void)
920 {
921 	redraw_window(minibuffer, 0, 10, body_cols,
922 	    &ministate.compl.buffer);
923 }
924 
925 /*
926  * Place the cursor in the right ncurses window.  If soft is 1, use
927  * wnoutrefresh (which shouldn't cause any I/O); otherwise use
928  * wrefresh.
929  */
930 static void
931 place_cursor(int soft)
932 {
933 	int (*touch)(WINDOW *);
934 
935 	if (soft)
936 		touch = wnoutrefresh;
937 	else
938 		touch = wrefresh;
939 
940 	if (in_minibuffer) {
941 		touch(body);
942 		touch(echoarea);
943 	} else {
944 		touch(echoarea);
945 		touch(body);
946 	}
947 }
948 
949 static void
950 redraw_tab(struct tab *tab)
951 {
952 	if (too_small)
953 		return;
954 
955 	if (side_window) {
956 		redraw_help();
957 		wnoutrefresh(help);
958 	}
959 
960 	redraw_tabline();
961 	redraw_body(tab);
962 	redraw_modeline(tab);
963 	redraw_minibuffer();
964 
965 	wnoutrefresh(tabline);
966 	wnoutrefresh(modeline);
967 
968 	if (in_minibuffer == MB_COMPREAD)
969 		wnoutrefresh(minibuffer);
970 
971 	place_cursor(1);
972 
973 	doupdate();
974 
975 	if (set_title)
976 		dprintf(1, "\033]0;%s - Telescope\a",
977 		    current_tab->buffer.page.title);
978 }
979 
980 static void
981 emit_help_item(char *prfx, void *fn)
982 {
983 	struct line	*l;
984 	struct cmd	*cmd;
985 
986 	for (cmd = cmds; cmd->cmd != NULL; ++cmd) {
987 		if (fn == cmd->fn)
988 			break;
989 	}
990 	assert(cmd != NULL);
991 
992 	if ((l = calloc(1, sizeof(*l))) == NULL)
993 		abort();
994 
995 	l->type = LINE_TEXT;
996 	l->alt = NULL;
997 
998 	asprintf(&l->line, "%s %s", prfx, cmd->cmd);
999 
1000 	if (TAILQ_EMPTY(&helpwin.page.head))
1001 		TAILQ_INSERT_HEAD(&helpwin.page.head, l, lines);
1002 	else
1003 		TAILQ_INSERT_TAIL(&helpwin.page.head, l, lines);
1004 }
1005 
1006 static void
1007 rec_compute_help(struct kmap *keymap, char *prfx, size_t len)
1008 {
1009 	struct keymap	*k;
1010 	char		 p[32];
1011 	const char	*kn;
1012 
1013 	TAILQ_FOREACH(k, &keymap->m, keymaps) {
1014 		strlcpy(p, prfx, sizeof(p));
1015 		if (*p != '\0')
1016 			strlcat(p, " ", sizeof(p));
1017 		if (k->meta)
1018 			strlcat(p, "M-", sizeof(p));
1019 		if ((kn = unkbd(k->key)) != NULL)
1020 			strlcat(p, kn, sizeof(p));
1021 		else
1022 			strlcat(p, keyname(k->key), sizeof(p));
1023 
1024 		if (k->fn == NULL)
1025 			rec_compute_help(&k->map, p, sizeof(p));
1026 		else
1027 			emit_help_item(p, k->fn);
1028 	}
1029 }
1030 
1031 static void
1032 recompute_help(void)
1033 {
1034 	char	p[32] = { 0 };
1035 
1036 	empty_vlist(&helpwin);
1037 	empty_linelist(&helpwin);
1038 	rec_compute_help(current_map, p, sizeof(p));
1039 	wrap_page(&helpwin, help_cols);
1040 }
1041 
1042 void
1043 vmessage(const char *fmt, va_list ap)
1044 {
1045 	if (evtimer_pending(&clechoev, NULL))
1046 		evtimer_del(&clechoev);
1047 
1048 	free(ministate.curmesg);
1049 	ministate.curmesg = NULL;
1050 
1051 	if (fmt != NULL) {
1052 		evtimer_set(&clechoev, handle_clear_echoarea, NULL);
1053 		evtimer_add(&clechoev, &clechoev_timer);
1054 
1055 		/* TODO: what to do if the allocation fails here? */
1056 		if (vasprintf(&ministate.curmesg, fmt, ap) == -1)
1057 			ministate.curmesg = NULL;
1058 	}
1059 
1060 	redraw_minibuffer();
1061         place_cursor(0);
1062 }
1063 
1064 void
1065 message(const char *fmt, ...)
1066 {
1067 	va_list ap;
1068 
1069 	va_start(ap, fmt);
1070 	vmessage(fmt, ap);
1071 	va_end(ap);
1072 }
1073 
1074 void
1075 start_loading_anim(struct tab *tab)
1076 {
1077 	if (tab->loading_anim)
1078 		return;
1079 	tab->loading_anim = 1;
1080 	evtimer_set(&tab->loadingev, update_loading_anim, tab);
1081 	evtimer_add(&tab->loadingev, &loadingev_timer);
1082 }
1083 
1084 static void
1085 update_loading_anim(int fd, short ev, void *d)
1086 {
1087 	struct tab	*tab = d;
1088 
1089 	tab->loading_anim_step = (tab->loading_anim_step+1)%4;
1090 
1091 	if (tab == current_tab) {
1092 		redraw_modeline(tab);
1093 		wrefresh(modeline);
1094 		wrefresh(body);
1095 		if (in_minibuffer)
1096 			wrefresh(echoarea);
1097 	}
1098 
1099 	evtimer_add(&tab->loadingev, &loadingev_timer);
1100 }
1101 
1102 static void
1103 stop_loading_anim(struct tab *tab)
1104 {
1105 	if (!tab->loading_anim)
1106 		return;
1107 	evtimer_del(&tab->loadingev);
1108 	tab->loading_anim = 0;
1109 	tab->loading_anim_step = 0;
1110 
1111 	if (tab != current_tab)
1112 		return;
1113 
1114 	redraw_modeline(tab);
1115 
1116 	wrefresh(modeline);
1117 	wrefresh(body);
1118 	if (in_minibuffer)
1119 		wrefresh(echoarea);
1120 }
1121 
1122 void
1123 load_url_in_tab(struct tab *tab, const char *url)
1124 {
1125 	if (!operating) {
1126 		load_url(tab, url);
1127 		return;
1128 	}
1129 
1130 	message("Loading %s...", url);
1131 	start_loading_anim(tab);
1132 	load_url(tab, url);
1133 
1134 	redraw_tab(tab);
1135 }
1136 
1137 void
1138 switch_to_tab(struct tab *tab)
1139 {
1140 	current_tab = tab;
1141 	tab->flags &= ~TAB_URGENT;
1142 
1143 	if (operating && tab->flags & TAB_LAZY)
1144 		load_url_in_tab(tab, tab->hist_cur->h);
1145 }
1146 
1147 unsigned int
1148 tab_new_id(void)
1149 {
1150 	return tab_counter++;
1151 }
1152 
1153 struct tab *
1154 new_tab(const char *url)
1155 {
1156 	struct tab	*tab;
1157 
1158 	if ((tab = calloc(1, sizeof(*tab))) == NULL) {
1159 		event_loopbreak();
1160 		return NULL;
1161 	}
1162 	tab->fd = -1;
1163 
1164 	TAILQ_INIT(&tab->hist.head);
1165 
1166 	TAILQ_INIT(&tab->buffer.head);
1167 
1168 	tab->id = tab_new_id();
1169 	if (!operating)
1170 		tab->flags |= TAB_LAZY;
1171 	switch_to_tab(tab);
1172 
1173 	if (TAILQ_EMPTY(&tabshead))
1174 		TAILQ_INSERT_HEAD(&tabshead, tab, tabs);
1175 	else
1176 		TAILQ_INSERT_TAIL(&tabshead, tab, tabs);
1177 
1178 	load_url_in_tab(tab, url);
1179 	return tab;
1180 }
1181 
1182 int
1183 ui_print_colors(void)
1184 {
1185 	int colors = 0, pairs = 0, can_change = 0;
1186 	int columns = 16, lines, color, i, j;
1187 
1188 	initscr();
1189 	if (has_colors()) {
1190 		start_color();
1191 		use_default_colors();
1192 
1193 		colors = COLORS;
1194 		pairs = COLOR_PAIRS;
1195 		can_change = can_change_color();
1196 	}
1197 	endwin();
1198 
1199 	printf("Term info:\n");
1200 	printf("TERM=%s COLORS=%d COLOR_PAIRS=%d can_change_colors=%d\n",
1201 	    getenv("TERM"), colors, pairs, can_change);
1202 	printf("\n");
1203 
1204 	if (colors == 0) {
1205 		printf("No color support\n");
1206 		return 0;
1207 	}
1208 
1209 	printf("Available colors:\n\n");
1210 	lines = (colors - 1) / columns + 1;
1211 	color = 0;
1212 	for (i = 0; i < lines; ++i) {
1213 		for (j = 0; j < columns; ++j, ++color) {
1214 			printf("\033[0;38;5;%dm %03d", color, color);
1215 		}
1216 		printf("\n");
1217 	}
1218 
1219 	printf("\033[0m");
1220 	fflush(stdout);
1221 	return 0;
1222 }
1223 
1224 int
1225 ui_init()
1226 {
1227 	setlocale(LC_ALL, "");
1228 
1229 	TAILQ_INIT(&eecmd_history.head);
1230 	TAILQ_INIT(&ir_history.head);
1231 	TAILQ_INIT(&lu_history.head);
1232 
1233 	ministate.line.type = LINE_TEXT;
1234 	ministate.vline.parent = &ministate.line;
1235 	ministate.buffer.current_line = &ministate.vline;
1236 
1237 	/* initialize help window */
1238 	TAILQ_INIT(&helpwin.head);
1239 
1240 	base_map = &global_map;
1241 	current_map = &global_map;
1242 
1243 	initscr();
1244 
1245 	if (enable_colors) {
1246 		if (has_colors()) {
1247 			start_color();
1248 			use_default_colors();
1249 		} else
1250 			enable_colors = 0;
1251 	}
1252 
1253 	config_apply_style();
1254 
1255 	raw();
1256 	noecho();
1257 	nonl();
1258 	intrflush(stdscr, FALSE);
1259 
1260 	if ((tabline = newwin(1, COLS, 0, 0)) == NULL)
1261 		return 0;
1262 	if ((body = newwin(LINES - 3, COLS, 1, 0)) == NULL)
1263 		return 0;
1264 	if ((modeline = newwin(1, COLS, LINES-2, 0)) == NULL)
1265 		return 0;
1266 	if ((echoarea = newwin(1, COLS, LINES-1, 0)) == NULL)
1267 		return 0;
1268 	if ((minibuffer = newwin(1, COLS, LINES-1, 0)) == NULL)
1269 		return 0;
1270 	if ((help = newwin(1, 1, 1, 0)) == NULL)
1271 		return 0;
1272 
1273 	body_lines = LINES-3;
1274 	body_cols = COLS;
1275 
1276 	wbkgd(body, body_face.body);
1277 	wbkgd(echoarea, minibuffer_face.background);
1278 
1279 	update_x_offset();
1280 
1281 	keypad(body, TRUE);
1282 	scrollok(body, FALSE);
1283 
1284 	/* non-blocking input */
1285 	wtimeout(body, 0);
1286 
1287 	mvwprintw(body, 0, 0, "");
1288 
1289 	/*
1290 	 * Dummy so libevent2 won't complain that no event_base is set
1291 	 * when checking event_pending for the first time
1292 	 */
1293 	evtimer_set(&clechoev, handle_clear_echoarea, NULL);
1294 	evtimer_add(&clechoev, &clechoev_timer);
1295 	evtimer_set(&resizeev, handle_resize, NULL);
1296 	evtimer_add(&resizeev, &resize_timer);
1297 
1298 	event_set(&stdioev, 0, EV_READ | EV_PERSIST, dispatch_stdio, NULL);
1299 	event_add(&stdioev, NULL);
1300 
1301 	signal_set(&winchev, SIGWINCH, handle_resize, NULL);
1302 	signal_add(&winchev, NULL);
1303 
1304 	return 1;
1305 }
1306 
1307 void
1308 ui_main_loop(void)
1309 {
1310 	operating = 1;
1311 	switch_to_tab(current_tab);
1312 	redraw_tab(current_tab);
1313 
1314 	event_dispatch();
1315 }
1316 
1317 void
1318 ui_on_tab_loaded(struct tab *tab)
1319 {
1320 	stop_loading_anim(tab);
1321 	message("Loaded %s", tab->hist_cur->h);
1322 
1323 	redraw_tabline();
1324 	wrefresh(tabline);
1325 	place_cursor(0);
1326 }
1327 
1328 void
1329 ui_on_tab_refresh(struct tab *tab)
1330 {
1331 	wrap_page(&tab->buffer, body_cols);
1332 	if (tab == current_tab)
1333 		redraw_tab(tab);
1334 	else
1335 		tab->flags |= TAB_URGENT;
1336 }
1337 
1338 const char *
1339 ui_keyname(int k)
1340 {
1341 	return keyname(k);
1342 }
1343 
1344 void
1345 ui_toggle_side_window(void)
1346 {
1347 	side_window = !side_window;
1348 	if (side_window)
1349 		recompute_help();
1350 
1351 	/*
1352 	 * ugly hack, but otherwise the window doesn't get updated
1353 	 * until I call rearrange_windows a second time (e.g. via
1354 	 * C-l).  I will be happy to know why something like this is
1355 	 * needed.
1356 	 */
1357 	rearrange_windows();
1358 	rearrange_windows();
1359 }
1360 
1361 void
1362 ui_schedule_redraw(void)
1363 {
1364 	should_rearrange_windows = 1;
1365 }
1366 
1367 void
1368 ui_require_input(struct tab *tab, int hide)
1369 {
1370 	/* TODO: hard-switching to another tab is ugly */
1371 	switch_to_tab(tab);
1372 
1373 	enter_minibuffer(ir_self_insert, ir_select, exit_minibuffer,
1374 	    &ir_history, NULL, NULL);
1375 	strlcpy(ministate.prompt, "Input required: ",
1376 	    sizeof(ministate.prompt));
1377 	redraw_tab(tab);
1378 }
1379 
1380 void
1381 ui_yornp(const char *prompt, void (*fn)(int, struct tab *),
1382     struct tab *data)
1383 {
1384 	yornp(prompt, fn, data);
1385 	redraw_tab(current_tab);
1386 }
1387 
1388 void
1389 ui_read(const char *prompt, void (*fn)(const char*, struct tab *),
1390     struct tab *data)
1391 {
1392 	completing_read(prompt, fn, data);
1393 	redraw_tab(current_tab);
1394 }
1395 
1396 void
1397 ui_suspend(void)
1398 {
1399 	endwin();
1400 
1401 	kill(getpid(), SIGSTOP);
1402 
1403 	refresh();
1404 	clear();
1405 	rearrange_windows();
1406 }
1407 
1408 void
1409 ui_end(void)
1410 {
1411 	endwin();
1412 }