menuconfig: Extend dialog_textbox so that it can return to a scrolled position
[linux-3.10.git] / scripts / kconfig / lxdialog / textbox.c
1 /*
2  *  textbox.c -- implements the text box
3  *
4  *  ORIGINAL AUTHOR: Savio Lam (lam836@cs.cuhk.hk)
5  *  MODIFIED FOR LINUX KERNEL CONFIG BY: William Roadcap (roadcap@cfw.com)
6  *
7  *  This program is free software; you can redistribute it and/or
8  *  modify it under the terms of the GNU General Public License
9  *  as published by the Free Software Foundation; either version 2
10  *  of the License, or (at your option) any later version.
11  *
12  *  This program is distributed in the hope that it will be useful,
13  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
14  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  *  GNU General Public License for more details.
16  *
17  *  You should have received a copy of the GNU General Public License
18  *  along with this program; if not, write to the Free Software
19  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20  */
21
22 #include "dialog.h"
23
24 static void back_lines(int n);
25 static void print_page(WINDOW * win, int height, int width);
26 static void print_line(WINDOW * win, int row, int width);
27 static char *get_line(void);
28 static void print_position(WINDOW * win);
29
30 static int hscroll;
31 static int begin_reached, end_reached, page_length;
32 static const char *buf;
33 static const char *page;
34
35 /*
36  * refresh window content
37  */
38 static void refresh_text_box(WINDOW *dialog, WINDOW *box, int boxh, int boxw,
39                                                           int cur_y, int cur_x)
40 {
41         print_page(box, boxh, boxw);
42         print_position(dialog);
43         wmove(dialog, cur_y, cur_x);    /* Restore cursor position */
44         wrefresh(dialog);
45 }
46
47
48 /*
49  * Display text from a file in a dialog box.
50  *
51  * keys is a null-terminated array
52  */
53 int dialog_textbox(const char *title, const char *tbuf, int initial_height,
54                    int initial_width, int *keys, int *_vscroll, int *_hscroll)
55 {
56         int i, x, y, cur_x, cur_y, key = 0;
57         int height, width, boxh, boxw;
58         WINDOW *dialog, *box;
59         bool done = false;
60
61         begin_reached = 1;
62         end_reached = 0;
63         page_length = 0;
64         hscroll = 0;
65         buf = tbuf;
66         page = buf;     /* page is pointer to start of page to be displayed */
67
68         if (_vscroll && *_vscroll) {
69                 begin_reached = 0;
70
71                 for (i = 0; i < *_vscroll; i++)
72                         get_line();
73         }
74         if (_hscroll)
75                 hscroll = *_hscroll;
76
77 do_resize:
78         getmaxyx(stdscr, height, width);
79         if (height < 8 || width < 8)
80                 return -ERRDISPLAYTOOSMALL;
81         if (initial_height != 0)
82                 height = initial_height;
83         else
84                 if (height > 4)
85                         height -= 4;
86                 else
87                         height = 0;
88         if (initial_width != 0)
89                 width = initial_width;
90         else
91                 if (width > 5)
92                         width -= 5;
93                 else
94                         width = 0;
95
96         /* center dialog box on screen */
97         x = (COLS - width) / 2;
98         y = (LINES - height) / 2;
99
100         draw_shadow(stdscr, y, x, height, width);
101
102         dialog = newwin(height, width, y, x);
103         keypad(dialog, TRUE);
104
105         /* Create window for box region, used for scrolling text */
106         boxh = height - 4;
107         boxw = width - 2;
108         box = subwin(dialog, boxh, boxw, y + 1, x + 1);
109         wattrset(box, dlg.dialog.atr);
110         wbkgdset(box, dlg.dialog.atr & A_COLOR);
111
112         keypad(box, TRUE);
113
114         /* register the new window, along with its borders */
115         draw_box(dialog, 0, 0, height, width,
116                  dlg.dialog.atr, dlg.border.atr);
117
118         wattrset(dialog, dlg.border.atr);
119         mvwaddch(dialog, height - 3, 0, ACS_LTEE);
120         for (i = 0; i < width - 2; i++)
121                 waddch(dialog, ACS_HLINE);
122         wattrset(dialog, dlg.dialog.atr);
123         wbkgdset(dialog, dlg.dialog.atr & A_COLOR);
124         waddch(dialog, ACS_RTEE);
125
126         print_title(dialog, title, width);
127
128         print_button(dialog, gettext(" Exit "), height - 2, width / 2 - 4, TRUE);
129         wnoutrefresh(dialog);
130         getyx(dialog, cur_y, cur_x);    /* Save cursor position */
131
132         /* Print first page of text */
133         attr_clear(box, boxh, boxw, dlg.dialog.atr);
134         refresh_text_box(dialog, box, boxh, boxw, cur_y, cur_x);
135
136         while (!done) {
137                 key = wgetch(dialog);
138                 switch (key) {
139                 case 'E':       /* Exit */
140                 case 'e':
141                 case 'X':
142                 case 'x':
143                 case 'q':
144                 case '\n':
145                         done = true;
146                         break;
147                 case 'g':       /* First page */
148                 case KEY_HOME:
149                         if (!begin_reached) {
150                                 begin_reached = 1;
151                                 page = buf;
152                                 refresh_text_box(dialog, box, boxh, boxw,
153                                                  cur_y, cur_x);
154                         }
155                         break;
156                 case 'G':       /* Last page */
157                 case KEY_END:
158
159                         end_reached = 1;
160                         /* point to last char in buf */
161                         page = buf + strlen(buf);
162                         back_lines(boxh);
163                         refresh_text_box(dialog, box, boxh, boxw,
164                                          cur_y, cur_x);
165                         break;
166                 case 'K':       /* Previous line */
167                 case 'k':
168                 case KEY_UP:
169                         if (!begin_reached) {
170                                 int passed_end = 0;
171
172                                 back_lines(page_length + 1);
173
174                                 /* We don't call print_page() here but use
175                                  * scrolling to ensure faster screen update.
176                                  * However, 'end_reached' and 'page_length'
177                                  * should still be updated, and 'page' should
178                                  * point to start of next page. This is done
179                                  * by calling get_line() in the following
180                                  * 'for' loop. */
181                                 scrollok(box, TRUE);
182                                 wscrl(box, -1); /* Scroll box region down one line */
183                                 scrollok(box, FALSE);
184                                 page_length = 0;
185                                 for (i = 0; i < boxh; i++) {
186                                         if (!i) {
187                                                 /* print first line of page */
188                                                 print_line(box, 0, boxw);
189                                                 wnoutrefresh(box);
190                                         } else
191                                                 /* Called to update 'end_reached' and 'page' */
192                                                 get_line();
193                                         if (!passed_end)
194                                                 page_length++;
195                                         if (end_reached && !passed_end)
196                                                 passed_end = 1;
197                                 }
198
199                                 print_position(dialog);
200                                 wmove(dialog, cur_y, cur_x);    /* Restore cursor position */
201                                 wrefresh(dialog);
202                         }
203                         break;
204                 case 'B':       /* Previous page */
205                 case 'b':
206                 case 'u':
207                 case KEY_PPAGE:
208                         if (begin_reached)
209                                 break;
210                         back_lines(page_length + boxh);
211                         refresh_text_box(dialog, box, boxh, boxw,
212                                          cur_y, cur_x);
213                         break;
214                 case 'J':       /* Next line */
215                 case 'j':
216                 case KEY_DOWN:
217                         if (!end_reached) {
218                                 begin_reached = 0;
219                                 scrollok(box, TRUE);
220                                 scroll(box);    /* Scroll box region up one line */
221                                 scrollok(box, FALSE);
222                                 print_line(box, boxh - 1, boxw);
223                                 wnoutrefresh(box);
224                                 print_position(dialog);
225                                 wmove(dialog, cur_y, cur_x);    /* Restore cursor position */
226                                 wrefresh(dialog);
227                         }
228                         break;
229                 case KEY_NPAGE: /* Next page */
230                 case ' ':
231                 case 'd':
232                         if (end_reached)
233                                 break;
234
235                         begin_reached = 0;
236                         refresh_text_box(dialog, box, boxh, boxw,
237                                          cur_y, cur_x);
238                         break;
239                 case '0':       /* Beginning of line */
240                 case 'H':       /* Scroll left */
241                 case 'h':
242                 case KEY_LEFT:
243                         if (hscroll <= 0)
244                                 break;
245
246                         if (key == '0')
247                                 hscroll = 0;
248                         else
249                                 hscroll--;
250                         /* Reprint current page to scroll horizontally */
251                         back_lines(page_length);
252                         refresh_text_box(dialog, box, boxh, boxw,
253                                          cur_y, cur_x);
254                         break;
255                 case 'L':       /* Scroll right */
256                 case 'l':
257                 case KEY_RIGHT:
258                         if (hscroll >= MAX_LEN)
259                                 break;
260                         hscroll++;
261                         /* Reprint current page to scroll horizontally */
262                         back_lines(page_length);
263                         refresh_text_box(dialog, box, boxh, boxw,
264                                          cur_y, cur_x);
265                         break;
266                 case KEY_ESC:
267                         if (on_key_esc(dialog) == KEY_ESC)
268                                 done = true;
269                         break;
270                 case KEY_RESIZE:
271                         back_lines(height);
272                         delwin(box);
273                         delwin(dialog);
274                         on_key_resize();
275                         goto do_resize;
276                 default:
277                         for (i = 0; keys[i]; i++) {
278                                 if (key == keys[i]) {
279                                         done = true;
280                                         break;
281                                 }
282                         }
283                 }
284         }
285         delwin(box);
286         delwin(dialog);
287         if (_vscroll) {
288                 const char *s;
289
290                 s = buf;
291                 *_vscroll = 0;
292                 back_lines(page_length);
293                 while (s < page && (s = strchr(s, '\n'))) {
294                         (*_vscroll)++;
295                         s++;
296                 }
297         }
298         if (_hscroll)
299                 *_hscroll = hscroll;
300         return key;
301 }
302
303 /*
304  * Go back 'n' lines in text. Called by dialog_textbox().
305  * 'page' will be updated to point to the desired line in 'buf'.
306  */
307 static void back_lines(int n)
308 {
309         int i;
310
311         begin_reached = 0;
312         /* Go back 'n' lines */
313         for (i = 0; i < n; i++) {
314                 if (*page == '\0') {
315                         if (end_reached) {
316                                 end_reached = 0;
317                                 continue;
318                         }
319                 }
320                 if (page == buf) {
321                         begin_reached = 1;
322                         return;
323                 }
324                 page--;
325                 do {
326                         if (page == buf) {
327                                 begin_reached = 1;
328                                 return;
329                         }
330                         page--;
331                 } while (*page != '\n');
332                 page++;
333         }
334 }
335
336 /*
337  * Print a new page of text. Called by dialog_textbox().
338  */
339 static void print_page(WINDOW * win, int height, int width)
340 {
341         int i, passed_end = 0;
342
343         page_length = 0;
344         for (i = 0; i < height; i++) {
345                 print_line(win, i, width);
346                 if (!passed_end)
347                         page_length++;
348                 if (end_reached && !passed_end)
349                         passed_end = 1;
350         }
351         wnoutrefresh(win);
352 }
353
354 /*
355  * Print a new line of text. Called by dialog_textbox() and print_page().
356  */
357 static void print_line(WINDOW * win, int row, int width)
358 {
359         char *line;
360
361         line = get_line();
362         line += MIN(strlen(line), hscroll);     /* Scroll horizontally */
363         wmove(win, row, 0);     /* move cursor to correct line */
364         waddch(win, ' ');
365         waddnstr(win, line, MIN(strlen(line), width - 2));
366
367         /* Clear 'residue' of previous line */
368 #if OLD_NCURSES
369         {
370                 int x = getcurx(win);
371                 int i;
372                 for (i = 0; i < width - x; i++)
373                         waddch(win, ' ');
374         }
375 #else
376         wclrtoeol(win);
377 #endif
378 }
379
380 /*
381  * Return current line of text. Called by dialog_textbox() and print_line().
382  * 'page' should point to start of current line before calling, and will be
383  * updated to point to start of next line.
384  */
385 static char *get_line(void)
386 {
387         int i = 0;
388         static char line[MAX_LEN + 1];
389
390         end_reached = 0;
391         while (*page != '\n') {
392                 if (*page == '\0') {
393                         end_reached = 1;
394                         break;
395                 } else if (i < MAX_LEN)
396                         line[i++] = *(page++);
397                 else {
398                         /* Truncate lines longer than MAX_LEN characters */
399                         if (i == MAX_LEN)
400                                 line[i++] = '\0';
401                         page++;
402                 }
403         }
404         if (i <= MAX_LEN)
405                 line[i] = '\0';
406         if (!end_reached)
407                 page++;         /* move past '\n' */
408
409         return line;
410 }
411
412 /*
413  * Print current position
414  */
415 static void print_position(WINDOW * win)
416 {
417         int percent;
418
419         wattrset(win, dlg.position_indicator.atr);
420         wbkgdset(win, dlg.position_indicator.atr & A_COLOR);
421         percent = (page - buf) * 100 / strlen(buf);
422         wmove(win, getmaxy(win) - 3, getmaxx(win) - 9);
423         wprintw(win, "(%3d%%)", percent);
424 }