util/kconfig/lxdialog/textbox.c

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