1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  *  textbox.c -- implements the text box
4  *
5  *  ORIGINAL AUTHOR: Savio Lam (lam836@cs.cuhk.hk)
6  *  MODIFIED FOR LINUX KERNEL CONFIG BY: William Roadcap (roadcap@cfw.com)
7  */
8 
9 #include "dialog.h"
10 
11 static void back_lines(int n);
12 static void print_page(WINDOW *win, int height, int width, update_text_fn
13 		       update_text, void *data);
14 static void print_line(WINDOW *win, int row, int width);
15 static char *get_line(void);
16 static void print_position(WINDOW * win);
17 
18 static int hscroll;
19 static int begin_reached, end_reached, page_length;
20 static char *buf;
21 static char *page;
22 
23 /*
24  * refresh window content
25  */
26 static void refresh_text_box(WINDOW *dialog, WINDOW *box, int boxh, int boxw,
27 			     int cur_y, int cur_x, update_text_fn update_text,
28 			     void *data)
29 {
30 	print_page(box, boxh, boxw, update_text, data);
31 	print_position(dialog);
32 	wmove(dialog, cur_y, cur_x);	/* Restore cursor position */
33 	wrefresh(dialog);
34 }
35 
36 
37 /*
38  * Display text from a file in a dialog box.
39  *
40  * keys is a null-terminated array
41  * update_text() may not add or remove any '\n' or '\0' in tbuf
42  */
43 int dialog_textbox(const char *title, char *tbuf, int initial_height,
44 		   int initial_width, int *keys, int *_vscroll, int *_hscroll,
45 		   update_text_fn update_text, void *data)
46 {
47 	int i, x, y, cur_x, cur_y, key = 0;
48 	int height, width, boxh, boxw;
49 	WINDOW *dialog, *box;
50 	bool done = false;
51 
52 	begin_reached = 1;
53 	end_reached = 0;
54 	page_length = 0;
55 	hscroll = 0;
56 	buf = tbuf;
57 	page = buf;	/* page is pointer to start of page to be displayed */
58 
59 	if (_vscroll && *_vscroll) {
60 		begin_reached = 0;
61 
62 		for (i = 0; i < *_vscroll; i++)
63 			get_line();
64 	}
65 	if (_hscroll)
66 		hscroll = *_hscroll;
67 
68 do_resize:
69 	getmaxyx(stdscr, height, width);
70 	if (height < TEXTBOX_HEIGTH_MIN || width < TEXTBOX_WIDTH_MIN)
71 		return -ERRDISPLAYTOOSMALL;
72 	if (initial_height != 0)
73 		height = initial_height;
74 	else
75 		if (height > 4)
76 			height -= 4;
77 		else
78 			height = 0;
79 	if (initial_width != 0)
80 		width = initial_width;
81 	else
82 		if (width > 5)
83 			width -= 5;
84 		else
85 			width = 0;
86 
87 	/* center dialog box on screen */
88 	x = (getmaxx(stdscr) - width) / 2;
89 	y = (getmaxy(stdscr) - height) / 2;
90 
91 	draw_shadow(stdscr, y, x, height, width);
92 
93 	dialog = newwin(height, width, y, x);
94 	keypad(dialog, TRUE);
95 
96 	/* Create window for box region, used for scrolling text */
97 	boxh = height - 4;
98 	boxw = width - 2;
99 	box = subwin(dialog, boxh, boxw, y + 1, x + 1);
100 	wattrset(box, dlg.dialog.atr);
101 	wbkgdset(box, dlg.dialog.atr & A_COLOR);
102 
103 	keypad(box, TRUE);
104 
105 	/* register the new window, along with its borders */
106 	draw_box(dialog, 0, 0, height, width,
107 		 dlg.dialog.atr, dlg.border.atr);
108 
109 	wattrset(dialog, dlg.border.atr);
110 	mvwaddch(dialog, height - 3, 0, ACS_LTEE);
111 	for (i = 0; i < width - 2; i++)
112 		waddch(dialog, ACS_HLINE);
113 	wattrset(dialog, dlg.dialog.atr);
114 	wbkgdset(dialog, dlg.dialog.atr & A_COLOR);
115 	waddch(dialog, ACS_RTEE);
116 
117 	print_title(dialog, title, width);
118 
119 	print_button(dialog, " Exit ", height - 2, width / 2 - 4, TRUE);
120 	wnoutrefresh(dialog);
121 	getyx(dialog, cur_y, cur_x);	/* Save cursor position */
122 
123 	/* Print first page of text */
124 	attr_clear(box, boxh, boxw, dlg.dialog.atr);
125 	refresh_text_box(dialog, box, boxh, boxw, cur_y, cur_x, update_text,
126 			 data);
127 
128 	while (!done) {
129 		key = wgetch(dialog);
130 		switch (key) {
131 		case 'E':	/* Exit */
132 		case 'e':
133 		case 'X':
134 		case 'x':
135 		case 'q':
136 		case '\n':
137 			done = true;
138 			break;
139 		case 'g':	/* First page */
140 		case KEY_HOME:
141 			if (!begin_reached) {
142 				begin_reached = 1;
143 				page = buf;
144 				refresh_text_box(dialog, box, boxh, boxw,
145 						 cur_y, cur_x, update_text,
146 						 data);
147 			}
148 			break;
149 		case 'G':	/* Last page */
150 		case KEY_END:
151 
152 			end_reached = 1;
153 			/* point to last char in buf */
154 			page = buf + strlen(buf);
155 			back_lines(boxh);
156 			refresh_text_box(dialog, box, boxh, boxw, cur_y,
157 					 cur_x, update_text, data);
158 			break;
159 		case 'K':	/* Previous line */
160 		case 'k':
161 		case KEY_UP:
162 			if (begin_reached)
163 				break;
164 
165 			back_lines(page_length + 1);
166 			refresh_text_box(dialog, box, boxh, boxw, cur_y,
167 					 cur_x, update_text, data);
168 			break;
169 		case 'B':	/* Previous page */
170 		case 'b':
171 		case 'u':
172 		case KEY_PPAGE:
173 			if (begin_reached)
174 				break;
175 			back_lines(page_length + boxh);
176 			refresh_text_box(dialog, box, boxh, boxw, cur_y,
177 					 cur_x, update_text, data);
178 			break;
179 		case 'J':	/* Next line */
180 		case 'j':
181 		case KEY_DOWN:
182 			if (end_reached)
183 				break;
184 
185 			back_lines(page_length - 1);
186 			refresh_text_box(dialog, box, boxh, boxw, cur_y,
187 					 cur_x, update_text, data);
188 			break;
189 		case KEY_NPAGE:	/* Next page */
190 		case ' ':
191 		case 'd':
192 			if (end_reached)
193 				break;
194 
195 			begin_reached = 0;
196 			refresh_text_box(dialog, box, boxh, boxw, cur_y,
197 					 cur_x, update_text, data);
198 			break;
199 		case '0':	/* Beginning of line */
200 		case 'H':	/* Scroll left */
201 		case 'h':
202 		case KEY_LEFT:
203 			if (hscroll <= 0)
204 				break;
205 
206 			if (key == '0')
207 				hscroll = 0;
208 			else
209 				hscroll--;
210 			/* Reprint current page to scroll horizontally */
211 			back_lines(page_length);
212 			refresh_text_box(dialog, box, boxh, boxw, cur_y,
213 					 cur_x, update_text, data);
214 			break;
215 		case 'L':	/* Scroll right */
216 		case 'l':
217 		case KEY_RIGHT:
218 			if (hscroll >= MAX_LEN)
219 				break;
220 			hscroll++;
221 			/* Reprint current page to scroll horizontally */
222 			back_lines(page_length);
223 			refresh_text_box(dialog, box, boxh, boxw, cur_y,
224 					 cur_x, update_text, data);
225 			break;
226 		case KEY_ESC:
227 			if (on_key_esc(dialog) == KEY_ESC)
228 				done = true;
229 			break;
230 		case KEY_RESIZE:
231 			back_lines(height);
232 			delwin(box);
233 			delwin(dialog);
234 			on_key_resize();
235 			goto do_resize;
236 		default:
237 			for (i = 0; keys[i]; i++) {
238 				if (key == keys[i]) {
239 					done = true;
240 					break;
241 				}
242 			}
243 		}
244 	}
245 	delwin(box);
246 	delwin(dialog);
247 	if (_vscroll) {
248 		const char *s;
249 
250 		s = buf;
251 		*_vscroll = 0;
252 		back_lines(page_length);
253 		while (s < page && (s = strchr(s, '\n'))) {
254 			(*_vscroll)++;
255 			s++;
256 		}
257 	}
258 	if (_hscroll)
259 		*_hscroll = hscroll;
260 	return key;
261 }
262 
263 /*
264  * Go back 'n' lines in text. Called by dialog_textbox().
265  * 'page' will be updated to point to the desired line in 'buf'.
266  */
267 static void back_lines(int n)
268 {
269 	int i;
270 
271 	begin_reached = 0;
272 	/* Go back 'n' lines */
273 	for (i = 0; i < n; i++) {
274 		if (*page == '\0') {
275 			if (end_reached) {
276 				end_reached = 0;
277 				continue;
278 			}
279 		}
280 		if (page == buf) {
281 			begin_reached = 1;
282 			return;
283 		}
284 		page--;
285 		do {
286 			if (page == buf) {
287 				begin_reached = 1;
288 				return;
289 			}
290 			page--;
291 		} while (*page != '\n');
292 		page++;
293 	}
294 }
295 
296 /*
297  * Print a new page of text.
298  */
299 static void print_page(WINDOW *win, int height, int width, update_text_fn
300 		       update_text, void *data)
301 {
302 	int i, passed_end = 0;
303 
304 	if (update_text) {
305 		char *end;
306 
307 		for (i = 0; i < height; i++)
308 			get_line();
309 		end = page;
310 		back_lines(height);
311 		update_text(buf, page - buf, end - buf, data);
312 	}
313 
314 	page_length = 0;
315 	for (i = 0; i < height; i++) {
316 		print_line(win, i, width);
317 		if (!passed_end)
318 			page_length++;
319 		if (end_reached && !passed_end)
320 			passed_end = 1;
321 	}
322 	wnoutrefresh(win);
323 }
324 
325 /*
326  * Print a new line of text.
327  */
328 static void print_line(WINDOW * win, int row, int width)
329 {
330 	char *line;
331 
332 	line = get_line();
333 	line += MIN(strlen(line), hscroll);	/* Scroll horizontally */
334 	wmove(win, row, 0);	/* move cursor to correct line */
335 	waddch(win, ' ');
336 	waddnstr(win, line, MIN(strlen(line), width - 2));
337 
338 	/* Clear 'residue' of previous line */
339 #if OLD_NCURSES
340 	{
341 		int x = getcurx(win);
342 		int i;
343 		for (i = 0; i < width - x; i++)
344 			waddch(win, ' ');
345 	}
346 #else
347 	wclrtoeol(win);
348 #endif
349 }
350 
351 /*
352  * Return current line of text. Called by dialog_textbox() and print_line().
353  * 'page' should point to start of current line before calling, and will be
354  * updated to point to start of next line.
355  */
356 static char *get_line(void)
357 {
358 	int i = 0;
359 	static char line[MAX_LEN + 1];
360 
361 	end_reached = 0;
362 	while (*page != '\n') {
363 		if (*page == '\0') {
364 			end_reached = 1;
365 			break;
366 		} else if (i < MAX_LEN)
367 			line[i++] = *(page++);
368 		else {
369 			/* Truncate lines longer than MAX_LEN characters */
370 			if (i == MAX_LEN)
371 				line[i++] = '\0';
372 			page++;
373 		}
374 	}
375 	if (i <= MAX_LEN)
376 		line[i] = '\0';
377 	if (!end_reached)
378 		page++;		/* move past '\n' */
379 
380 	return line;
381 }
382 
383 /*
384  * Print current position
385  */
386 static void print_position(WINDOW * win)
387 {
388 	int percent;
389 
390 	wattrset(win, dlg.position_indicator.atr);
391 	wbkgdset(win, dlg.position_indicator.atr & A_COLOR);
392 	percent = (page - buf) * 100 / strlen(buf);
393 	wmove(win, getmaxy(win) - 3, getmaxx(win) - 9);
394 	wprintw(win, "(%3d%%)", percent);
395 }
396