src/help.c

src/help.c
/* */
This source file includes following definitions.
search_string
search_string_node
search_char_node
move_forward2
move_backward2
move_forward
move_backward
move_to_top
move_to_bottom
help_follow_link
select_next_link
select_prev_link
start_link_area
end_link_area
clear_link_areas
help_print_word
help_show
help_help
help_index
help_back
help_next_link
help_prev_link
help_next_node
help_prev_node
help_select_link
help_execute_cmd
help_handle_key
help_bg_callback
help_resize
help_callback
interactive_display_finish
translate_file
md_callback
help_mouse_callback
mousedispatch_new
help_interactive_display
   1 /*
   2    Hypertext file browser.
   3 
   4    Copyright (C) 1994-2025
   5    Free Software Foundation, Inc.
   6 
   7    This file is part of the Midnight Commander.
   8 
   9    The Midnight Commander is free software: you can redistribute it
  10    and/or modify it under the terms of the GNU General Public License as
  11    published by the Free Software Foundation, either version 3 of the License,
  12    or (at your option) any later version.
  13 
  14    The Midnight Commander is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18 
  19    You should have received a copy of the GNU General Public License
  20    along with this program.  If not, see <https://www.gnu.org/licenses/>.
  21  */
  22 
  23 /** \file help.c
  24  *  \brief Source: hypertext file browser
  25  *
  26  *  Implements the hypertext file viewer.
  27  *  The hypertext file is a file that may have one or more nodes.  Each
  28  *  node ends with a ^D character and starts with a bracket, then the
  29  *  name of the node and then a closing bracket. Right after the closing
  30  *  bracket a newline is placed. This newline is not to be displayed by
  31  *  the help viewer and must be skipped - its sole purpose is to facilitate
  32  *  the work of the people managing the help file template (xnc.hlp) .
  33  *
  34  *  Links in the hypertext file are specified like this: the text that
  35  *  will be highlighted should have a leading ^A, then it comes the
  36  *  text, then a ^B indicating that highlighting is done, then the name
  37  *  of the node you want to link to and then a ^C.
  38  *
  39  *  The file must contain a ^D at the beginning and at the end of the
  40  *  file or the program will not be able to detect the end of file.
  41  *
  42  *  Laziness/widgeting attack: This file does use the dialog manager
  43  *  and uses mainly the dialog to achieve the help work.  there is only
  44  *  one specialized widget and it's only used to forward the mouse messages
  45  *  to the appropriate routine.
  46  */
  47 
  48 #include <config.h>
  49 
  50 #include <errno.h>
  51 #include <limits.h>  // MB_LEN_MAX
  52 #include <stdio.h>
  53 #include <sys/types.h>
  54 #include <sys/stat.h>
  55 
  56 #include "lib/global.h"
  57 
  58 #include "lib/tty/tty.h"
  59 #include "lib/skin.h"
  60 #include "lib/strutil.h"
  61 #include "lib/fileloc.h"
  62 #include "lib/util.h"
  63 #include "lib/widget.h"
  64 #include "lib/event-types.h"
  65 
  66 #include "keymap.h"
  67 #include "help.h"
  68 
  69 /*** global variables ****************************************************************************/
  70 
  71 /*** file scope macro definitions ****************************************************************/
  72 
  73 #define MAXLINKNAME         80
  74 #define HISTORY_SIZE        20
  75 #define HELP_WINDOW_WIDTH   MIN (80, COLS - 16)
  76 
  77 #define STRING_LINK_START   "\01"
  78 #define STRING_LINK_POINTER "\02"
  79 #define STRING_LINK_END     "\03"
  80 #define STRING_NODE_END     "\04"
  81 
  82 /*** file scope type declarations ****************************************************************/
  83 
  84 /* Link areas for the mouse */
  85 typedef struct Link_Area
  86 {
  87     int x1, y1, x2, y2;
  88     const char *link_name;
  89 } Link_Area;
  90 
  91 /*** forward declarations (file scope functions) *************************************************/
  92 
  93 /*** file scope variables ************************************************************************/
  94 
  95 static char *fdata = NULL;             // Pointer to the loaded data file
  96 static int help_lines;                 // Lines in help viewer
  97 static int history_ptr = 0;            // For the history queue
  98 static const char *main_node;          // The main node
  99 static const char *last_shown = NULL;  // Last byte shown in a screen
 100 static gboolean end_of_node = FALSE;   // Flag: the last character of the node shown?
 101 static const char *currentpoint;
 102 static const char *selected_item;
 103 
 104 /* The widget variables */
 105 static WDialog *whelp;
 106 
 107 static struct
 108 {
 109     const char *page;  // Pointer to the selected page
 110     const char *link;  // Pointer to the selected link
 111 } history[HISTORY_SIZE];
 112 
 113 static GSList *link_area = NULL;
 114 static gboolean inside_link_area = FALSE;
 115 
 116 /* --------------------------------------------------------------------------------------------- */
 117 /*** file scope functions ************************************************************************/
 118 /* --------------------------------------------------------------------------------------------- */
 119 
 120 /** returns the position where text was found in the start buffer
 121  * or 0 if not found
 122  */
 123 static const char *
 124 search_string (const char *start, const char *text)
     /*   */
 125 {
 126     const char *result = NULL;
 127     char *local_text;
 128     char *d;
 129     const char *e = start;
 130 
 131     local_text = g_strdup (text);
 132 
 133     // fmt sometimes replaces a space with a newline in the help file
 134     // Replace the newlines in the link name with spaces to correct the situation
 135     for (d = local_text; *d != '\0'; str_next_char (&d))
 136         if (*d == '\n')
 137             *d = ' ';
 138 
 139     // Do search
 140     for (d = local_text; *e != '\0'; e++)
 141     {
 142         if (*d == *e)
 143             d++;
 144         else
 145             d = local_text;
 146         if (*d == '\0')
 147         {
 148             result = e + 1;
 149             break;
 150         }
 151     }
 152 
 153     g_free (local_text);
 154     return result;
 155 }
 156 
 157 /* --------------------------------------------------------------------------------------------- */
 158 /** Searches text in the buffer pointed by start.  Search ends
 159  * if the CHAR_NODE_END is found in the text.
 160  * @return NULL on failure
 161  */
 162 
 163 static const char *
 164 search_string_node (const char *start, const char *text)
     /*   */
 165 {
 166     if (start != NULL)
 167     {
 168         const char *d = text;
 169         const char *e;
 170 
 171         for (e = start; *e != '\0' && *e != CHAR_NODE_END; e++)
 172         {
 173             if (*d == *e)
 174                 d++;
 175             else
 176                 d = text;
 177             if (*d == '\0')
 178                 return e + 1;
 179         }
 180     }
 181 
 182     return NULL;
 183 }
 184 
 185 /* --------------------------------------------------------------------------------------------- */
 186 /** Searches the_char in the buffer pointer by start and searches
 187  * it can search forward (direction = 1) or backward (direction = -1)
 188  */
 189 
 190 static const char *
 191 search_char_node (const char *start, char the_char, int direction)
     /*   */
 192 {
 193     const char *e;
 194 
 195     for (e = start; (*e != '\0') && (*e != CHAR_NODE_END); e += direction)
 196         if (*e == the_char)
 197             return e;
 198 
 199     return NULL;
 200 }
 201 
 202 /* --------------------------------------------------------------------------------------------- */
 203 /** Returns the new current pointer when moved lines lines */
 204 
 205 static const char *
 206 move_forward2 (const char *c, int lines)
     /*   */
 207 {
 208     const char *p;
 209     int line;
 210 
 211     currentpoint = c;
 212     for (line = 0, p = currentpoint; (*p != '\0') && (*p != CHAR_NODE_END); str_cnext_char (&p))
 213     {
 214         if (line == lines)
 215             return currentpoint = p;
 216 
 217         if (*p == '\n')
 218             line++;
 219     }
 220     return currentpoint = c;
 221 }
 222 
 223 /* --------------------------------------------------------------------------------------------- */
 224 
 225 static const char *
 226 move_backward2 (const char *c, int lines)
     /*   */
 227 {
 228     const char *p;
 229     int line;
 230 
 231     currentpoint = c;
 232     for (line = 0, p = currentpoint; (*p != '\0') && ((int) (p - fdata) >= 0); str_cprev_char (&p))
 233     {
 234         if (*p == CHAR_NODE_END)
 235         {
 236             // We reached the beginning of the node
 237             // Skip the node headers
 238             while (*p != ']')
 239                 str_cnext_char (&p);
 240             return currentpoint = p + 2;  // Skip the newline following the start of the node
 241         }
 242 
 243         if (*(p - 1) == '\n')
 244             line++;
 245         if (line == lines)
 246             return currentpoint = p;
 247     }
 248     return currentpoint = c;
 249 }
 250 
 251 /* --------------------------------------------------------------------------------------------- */
 252 
 253 static void
 254 move_forward (int i)
     /*   */
 255 {
 256     if (!end_of_node)
 257         currentpoint = move_forward2 (currentpoint, i);
 258 }
 259 
 260 /* --------------------------------------------------------------------------------------------- */
 261 
 262 static void
 263 move_backward (int i)
     /*   */
 264 {
 265     currentpoint = move_backward2 (currentpoint, ++i);
 266 }
 267 
 268 /* --------------------------------------------------------------------------------------------- */
 269 
 270 static void
 271 move_to_top (void)
     /*   */
 272 {
 273     while (((int) (currentpoint - fdata) > 0) && (*currentpoint != CHAR_NODE_END))
 274         currentpoint--;
 275 
 276     while (*currentpoint != ']')
 277         currentpoint++;
 278     currentpoint = currentpoint + 2;  // Skip the newline following the start of the node
 279     selected_item = NULL;
 280 }
 281 
 282 /* --------------------------------------------------------------------------------------------- */
 283 
 284 static void
 285 move_to_bottom (void)
     /*   */
 286 {
 287     while ((*currentpoint != '\0') && (*currentpoint != CHAR_NODE_END))
 288         currentpoint++;
 289     currentpoint--;
 290     move_backward (1);
 291 }
 292 
 293 /* --------------------------------------------------------------------------------------------- */
 294 
 295 static const char *
 296 help_follow_link (const char *start, const char *lc_selected_item)
     /*   */
 297 {
 298     const char *p;
 299 
 300     if (lc_selected_item == NULL)
 301         return start;
 302 
 303     for (p = lc_selected_item; *p != '\0' && *p != CHAR_NODE_END && *p != CHAR_LINK_POINTER; p++)
 304         ;
 305     if (*p == CHAR_LINK_POINTER)
 306     {
 307         int i;
 308         char link_name[MAXLINKNAME];
 309 
 310         link_name[0] = '[';
 311         for (i = 1;
 312              *p != CHAR_LINK_END && *p != '\0' && *p != CHAR_NODE_END && i < MAXLINKNAME - 3;)
 313             link_name[i++] = *++p;
 314         link_name[i - 1] = ']';
 315         link_name[i] = '\0';
 316         p = search_string (fdata, link_name);
 317         if (p != NULL)
 318         {
 319             p += 1;  // Skip the newline following the start of the node
 320             return p;
 321         }
 322     }
 323 
 324     // Create a replacement page with the error message
 325     return _ ("Help file format error\n");
 326 }
 327 
 328 /* --------------------------------------------------------------------------------------------- */
 329 
 330 static const char *
 331 select_next_link (const char *current_link)
     /*   */
 332 {
 333     const char *p;
 334 
 335     if (current_link == NULL)
 336         return NULL;
 337 
 338     p = search_string_node (current_link, STRING_LINK_END);
 339     if (p == NULL)
 340         return NULL;
 341     p = search_string_node (p, STRING_LINK_START);
 342     if (p == NULL)
 343         return NULL;
 344     return p - 1;
 345 }
 346 
 347 /* --------------------------------------------------------------------------------------------- */
 348 
 349 static const char *
 350 select_prev_link (const char *current_link)
     /*   */
 351 {
 352     return current_link == NULL ? NULL : search_char_node (current_link - 1, CHAR_LINK_START, -1);
 353 }
 354 
 355 /* --------------------------------------------------------------------------------------------- */
 356 
 357 static void
 358 start_link_area (int x, int y, const char *link_name)
     /*   */
 359 {
 360     Link_Area *la;
 361 
 362     if (inside_link_area)
 363         message (D_NORMAL, _ ("Warning"), "%s", _ ("Internal bug: Double start of link area"));
 364 
 365     // Allocate memory for a new link area
 366     la = g_new (Link_Area, 1);
 367     // Save the beginning coordinates of the link area
 368     la->x1 = x;
 369     la->y1 = y;
 370     // Save the name of the destination anchor
 371     la->link_name = link_name;
 372     link_area = g_slist_prepend (link_area, la);
 373 
 374     inside_link_area = TRUE;
 375 }
 376 
 377 /* --------------------------------------------------------------------------------------------- */
 378 
 379 static void
 380 end_link_area (int x, int y)
     /*   */
 381 {
 382     if (inside_link_area)
 383     {
 384         Link_Area *la = (Link_Area *) link_area->data;
 385         // Save the end coordinates of the link area
 386         la->x2 = x;
 387         la->y2 = y;
 388         inside_link_area = FALSE;
 389     }
 390 }
 391 
 392 /* --------------------------------------------------------------------------------------------- */
 393 
 394 static void
 395 clear_link_areas (void)
     /*   */
 396 {
 397     g_clear_slist (&link_area, g_free);
 398     inside_link_area = FALSE;
 399 }
 400 
 401 /* --------------------------------------------------------------------------------------------- */
 402 
 403 static void
 404 help_print_word (WDialog *h, GString *word, int *col, int *line, gboolean add_space)
     /*   */
 405 {
 406     if (*line >= help_lines)
 407         g_string_set_size (word, 0);
 408     else
 409     {
 410         int w;
 411 
 412         w = str_term_width1 (word->str);
 413         if (*col + w >= HELP_WINDOW_WIDTH)
 414         {
 415             *col = 0;
 416             (*line)++;
 417         }
 418 
 419         if (*line >= help_lines)
 420             g_string_set_size (word, 0);
 421         else
 422         {
 423             widget_gotoyx (h, *line + 2, *col + 2);
 424             tty_print_string (word->str);
 425             g_string_set_size (word, 0);
 426             *col += w;
 427         }
 428     }
 429 
 430     if (add_space)
 431     {
 432         if (*col < HELP_WINDOW_WIDTH - 1)
 433         {
 434             tty_print_char (' ');
 435             (*col)++;
 436         }
 437         else
 438         {
 439             *col = 0;
 440             (*line)++;
 441         }
 442     }
 443 }
 444 
 445 /* --------------------------------------------------------------------------------------------- */
 446 
 447 static void
 448 help_show (WDialog *h, const char *paint_start)
     /*   */
 449 {
 450     gboolean painting = TRUE;
 451     gboolean repeat_paint;
 452     int active_col, active_line;  // Active link position
 453     char buff[MB_LEN_MAX + 1];
 454     GString *word;
 455 
 456     word = g_string_sized_new (32);
 457 
 458     tty_setcolor (HELP_NORMAL_COLOR);
 459     do
 460     {
 461         int line = 0;
 462         int col = 0;
 463         gboolean acs = FALSE;  // Flag: Is alternate character set active?
 464         const char *p, *n;
 465 
 466         active_col = 0;
 467         active_line = 0;
 468 
 469         repeat_paint = FALSE;
 470 
 471         clear_link_areas ();
 472         if ((int) (selected_item - paint_start) < 0)
 473             selected_item = NULL;
 474 
 475         p = paint_start;
 476         n = paint_start;
 477         while ((n[0] != '\0') && (n[0] != CHAR_NODE_END) && (line < help_lines))
 478         {
 479             int c;
 480 
 481             p = n;
 482             n = str_cget_next_char (p);
 483             memcpy (buff, p, n - p);
 484             buff[n - p] = '\0';
 485 
 486             c = (unsigned char) buff[0];
 487             switch (c)
 488             {
 489             case CHAR_LINK_START:
 490                 if (selected_item == NULL)
 491                     selected_item = p;
 492                 if (p != selected_item)
 493                     tty_setcolor (HELP_LINK_COLOR);
 494                 else
 495                 {
 496                     tty_setcolor (HELP_SLINK_COLOR);
 497 
 498                     // Store the coordinates of the link
 499                     active_col = col + 2;
 500                     active_line = line + 2;
 501                 }
 502                 start_link_area (col, line, p);
 503                 break;
 504             case CHAR_LINK_POINTER:
 505                 painting = FALSE;
 506                 break;
 507             case CHAR_LINK_END:
 508                 painting = TRUE;
 509                 help_print_word (h, word, &col, &line, FALSE);
 510                 end_link_area (col - 1, line);
 511                 tty_setcolor (HELP_NORMAL_COLOR);
 512                 break;
 513             case CHAR_ALTERNATE:
 514                 acs = TRUE;
 515                 break;
 516             case CHAR_NORMAL:
 517                 acs = FALSE;
 518                 break;
 519             case CHAR_VERSION:
 520                 widget_gotoyx (h, line + 2, col + 2);
 521                 tty_print_string (mc_global.mc_version);
 522                 col += str_term_width1 (mc_global.mc_version);
 523                 break;
 524             case CHAR_FONT_BOLD:
 525                 tty_setcolor (HELP_BOLD_COLOR);
 526                 break;
 527             case CHAR_FONT_ITALIC:
 528                 tty_setcolor (HELP_ITALIC_COLOR);
 529                 break;
 530             case CHAR_FONT_NORMAL:
 531                 help_print_word (h, word, &col, &line, FALSE);
 532                 tty_setcolor (HELP_NORMAL_COLOR);
 533                 break;
 534             case '\n':
 535                 if (painting)
 536                     help_print_word (h, word, &col, &line, FALSE);
 537                 line++;
 538                 col = 0;
 539                 break;
 540             case ' ':
 541             case '\t':
 542                 // word delimiter
 543                 if (painting)
 544                 {
 545                     help_print_word (h, word, &col, &line, c == ' ');
 546                     if (c == '\t')
 547                     {
 548                         col = (col / 8 + 1) * 8;
 549                         if (col >= HELP_WINDOW_WIDTH)
 550                         {
 551                             line++;
 552                             col = 8;
 553                         }
 554                     }
 555                 }
 556                 break;
 557             default:
 558                 if (painting && (line < help_lines))
 559                 {
 560                     if (!acs)
 561                         // accumulate symbols in a word
 562                         g_string_append (word, buff);
 563                     else if (col < HELP_WINDOW_WIDTH)
 564                     {
 565                         widget_gotoyx (h, line + 2, col + 2);
 566 
 567                         if ((c == ' ') || (c == '.'))
 568                             tty_print_char (c);
 569                         else
 570 #ifndef HAVE_SLANG
 571                             tty_print_char (acs_map[c]);
 572 #else
 573                             SLsmg_draw_object (WIDGET (h)->rect.y + line + 2,
 574                                                WIDGET (h)->rect.x + col + 2, c);
 575 #endif
 576                         col++;
 577                     }
 578                 }
 579             }
 580         }
 581 
 582         // print last word
 583         if (n[0] == CHAR_NODE_END)
 584             help_print_word (h, word, &col, &line, FALSE);
 585 
 586         last_shown = p;
 587         end_of_node = line < help_lines;
 588         tty_setcolor (HELP_NORMAL_COLOR);
 589         if ((int) (selected_item - last_shown) >= 0)
 590         {
 591             if ((link_area == NULL) || (link_area->data == NULL))
 592                 selected_item = NULL;
 593             else
 594             {
 595                 selected_item = ((Link_Area *) link_area->data)->link_name;
 596                 repeat_paint = TRUE;
 597             }
 598         }
 599     }
 600     while (repeat_paint);
 601 
 602     g_string_free (word, TRUE);
 603 
 604     // Position the cursor over a nice link
 605     if (active_col != 0)
 606         widget_gotoyx (h, active_line, active_col);
 607 }
 608 
 609 /* --------------------------------------------------------------------------------------------- */
 610 /** show help */
 611 
 612 static void
 613 help_help (WDialog *h)
     /*   */
 614 {
 615     const char *p;
 616 
 617     history_ptr = (history_ptr + 1) % HISTORY_SIZE;
 618     history[history_ptr].page = currentpoint;
 619     history[history_ptr].link = selected_item;
 620 
 621     p = search_string (fdata, "[How to use help]");
 622     if (p != NULL)
 623     {
 624         currentpoint = p + 1;  // Skip the newline following the start of the node
 625         selected_item = NULL;
 626         widget_draw (WIDGET (h));
 627     }
 628 }
 629 
 630 /* --------------------------------------------------------------------------------------------- */
 631 
 632 static void
 633 help_index (WDialog *h)
     /*   */
 634 {
 635     const char *new_item;
 636 
 637     new_item = search_string (fdata, "[Contents]");
 638 
 639     if (new_item == NULL)
 640         message (D_ERROR, MSG_ERROR, _ ("Cannot find node %s in help file"), "[Contents]");
 641     else
 642     {
 643         history_ptr = (history_ptr + 1) % HISTORY_SIZE;
 644         history[history_ptr].page = currentpoint;
 645         history[history_ptr].link = selected_item;
 646 
 647         currentpoint = new_item + 1;  // Skip the newline following the start of the node
 648         selected_item = NULL;
 649         widget_draw (WIDGET (h));
 650     }
 651 }
 652 
 653 /* --------------------------------------------------------------------------------------------- */
 654 
 655 static void
 656 help_back (WDialog *h)
     /*   */
 657 {
 658     currentpoint = history[history_ptr].page;
 659     selected_item = history[history_ptr].link;
 660     history_ptr--;
 661     if (history_ptr < 0)
 662         history_ptr = HISTORY_SIZE - 1;
 663 
 664     widget_draw (WIDGET (h));  // FIXME: unneeded?
 665 }
 666 
 667 /* --------------------------------------------------------------------------------------------- */
 668 
 669 static void
 670 help_next_link (gboolean move_down)
     /*   */
 671 {
 672     const char *new_item;
 673 
 674     new_item = select_next_link (selected_item);
 675     if (new_item != NULL)
 676     {
 677         selected_item = new_item;
 678         if ((int) (selected_item - last_shown) >= 0)
 679         {
 680             if (move_down)
 681                 move_forward (1);
 682             else
 683                 selected_item = NULL;
 684         }
 685     }
 686     else if (move_down)
 687         move_forward (1);
 688     else
 689         selected_item = NULL;
 690 }
 691 
 692 /* --------------------------------------------------------------------------------------------- */
 693 
 694 static void
 695 help_prev_link (gboolean move_up)
     /*   */
 696 {
 697     const char *new_item;
 698 
 699     new_item = select_prev_link (selected_item);
 700     selected_item = new_item;
 701     if ((selected_item == NULL) || (selected_item < currentpoint))
 702     {
 703         if (move_up)
 704             move_backward (1);
 705         else if ((link_area != NULL) && (link_area->data != NULL))
 706             selected_item = ((Link_Area *) link_area->data)->link_name;
 707         else
 708             selected_item = NULL;
 709     }
 710 }
 711 
 712 /* --------------------------------------------------------------------------------------------- */
 713 
 714 static void
 715 help_next_node (void)
     /*   */
 716 {
 717     const char *new_item;
 718 
 719     new_item = currentpoint;
 720     while ((*new_item != '\0') && (*new_item != CHAR_NODE_END))
 721         new_item++;
 722 
 723     if (*++new_item == '[')
 724         while (*++new_item != '\0')
 725             if ((*new_item == ']') && (*++new_item != '\0') && (*++new_item != '\0'))
 726             {
 727                 currentpoint = new_item;
 728                 selected_item = NULL;
 729                 break;
 730             }
 731 }
 732 
 733 /* --------------------------------------------------------------------------------------------- */
 734 
 735 static void
 736 help_prev_node (void)
     /*   */
 737 {
 738     const char *new_item;
 739 
 740     new_item = currentpoint;
 741     while (((int) (new_item - fdata) > 1) && (*new_item != CHAR_NODE_END))
 742         new_item--;
 743     new_item--;
 744     while (((int) (new_item - fdata) > 0) && (*new_item != CHAR_NODE_END))
 745         new_item--;
 746     while (*new_item != ']')
 747         new_item++;
 748     currentpoint = new_item + 2;
 749     selected_item = NULL;
 750 }
 751 
 752 /* --------------------------------------------------------------------------------------------- */
 753 
 754 static void
 755 help_select_link (void)
     /*   */
 756 {
 757     // follow link
 758     if (selected_item == NULL)
 759     {
 760 #ifdef WE_WANT_TO_GO_BACKWARD_ON_KEY_RIGHT
 761         /* Is there any reason why the right key would take us
 762          * backward if there are no links selected?, I agree
 763          * with Torben than doing nothing in this case is better
 764          */
 765         // If there are no links, go backward in history
 766         history_ptr--;
 767         if (history_ptr < 0)
 768             history_ptr = HISTORY_SIZE - 1;
 769 
 770         currentpoint = history[history_ptr].page;
 771         selected_item = history[history_ptr].link;
 772 #endif
 773     }
 774     else
 775     {
 776         history_ptr = (history_ptr + 1) % HISTORY_SIZE;
 777         history[history_ptr].page = currentpoint;
 778         history[history_ptr].link = selected_item;
 779         currentpoint = help_follow_link (currentpoint, selected_item);
 780     }
 781 
 782     selected_item = NULL;
 783 }
 784 
 785 /* --------------------------------------------------------------------------------------------- */
 786 
 787 static cb_ret_t
 788 help_execute_cmd (long command)
     /*   */
 789 {
 790     cb_ret_t ret = MSG_HANDLED;
 791 
 792     switch (command)
 793     {
 794     case CK_Help:
 795         help_help (whelp);
 796         break;
 797     case CK_Index:
 798         help_index (whelp);
 799         break;
 800     case CK_Back:
 801         help_back (whelp);
 802         break;
 803     case CK_Up:
 804         help_prev_link (TRUE);
 805         break;
 806     case CK_Down:
 807         help_next_link (TRUE);
 808         break;
 809     case CK_PageDown:
 810         move_forward (help_lines - 1);
 811         break;
 812     case CK_PageUp:
 813         move_backward (help_lines - 1);
 814         break;
 815     case CK_HalfPageDown:
 816         move_forward (help_lines / 2);
 817         break;
 818     case CK_HalfPageUp:
 819         move_backward (help_lines / 2);
 820         break;
 821     case CK_Top:
 822         move_to_top ();
 823         break;
 824     case CK_Bottom:
 825         move_to_bottom ();
 826         break;
 827     case CK_Enter:
 828         help_select_link ();
 829         break;
 830     case CK_LinkNext:
 831         help_next_link (FALSE);
 832         break;
 833     case CK_LinkPrev:
 834         help_prev_link (FALSE);
 835         break;
 836     case CK_NodeNext:
 837         help_next_node ();
 838         break;
 839     case CK_NodePrev:
 840         help_prev_node ();
 841         break;
 842     case CK_Quit:
 843         dlg_close (whelp);
 844         break;
 845     default:
 846         ret = MSG_NOT_HANDLED;
 847     }
 848 
 849     return ret;
 850 }
 851 
 852 /* --------------------------------------------------------------------------------------------- */
 853 
 854 static cb_ret_t
 855 help_handle_key (WDialog *h, int key)
     /*   */
 856 {
 857     Widget *w = WIDGET (h);
 858     long command;
 859 
 860     command = widget_lookup_key (w, key);
 861     if (command == CK_IgnoreKey)
 862         return MSG_NOT_HANDLED;
 863 
 864     return help_execute_cmd (command);
 865 }
 866 
 867 /* --------------------------------------------------------------------------------------------- */
 868 
 869 static cb_ret_t
 870 help_bg_callback (Widget *w, Widget *sender, widget_msg_t msg, int parm, void *data)
     /*   */
 871 {
 872     switch (msg)
 873     {
 874     case MSG_DRAW:
 875         frame_callback (w, NULL, MSG_DRAW, 0, NULL);
 876         help_show (DIALOG (w->owner), currentpoint);
 877         return MSG_HANDLED;
 878 
 879     default:
 880         return frame_callback (w, sender, msg, parm, data);
 881     }
 882 }
 883 
 884 /* --------------------------------------------------------------------------------------------- */
 885 
 886 static cb_ret_t
 887 help_resize (WDialog *h)
     /*   */
 888 {
 889     Widget *w = WIDGET (h);
 890     WButtonBar *bb;
 891     WRect r = w->rect;
 892 
 893     help_lines = MIN (LINES - 4, MAX (2 * LINES / 3, 18));
 894     r.lines = help_lines + 4;
 895     r.cols = HELP_WINDOW_WIDTH + 4;
 896     dlg_default_callback (w, NULL, MSG_RESIZE, 0, &r);
 897     bb = buttonbar_find (h);
 898     widget_set_size (WIDGET (bb), LINES - 1, 0, 1, COLS);
 899 
 900     return MSG_HANDLED;
 901 }
 902 
 903 /* --------------------------------------------------------------------------------------------- */
 904 
 905 static cb_ret_t
 906 help_callback (Widget *w, Widget *sender, widget_msg_t msg, int parm, void *data)
     /*   */
 907 {
 908     WDialog *h = DIALOG (w);
 909 
 910     switch (msg)
 911     {
 912     case MSG_RESIZE:
 913         return help_resize (h);
 914 
 915     case MSG_KEY:
 916     {
 917         cb_ret_t ret;
 918 
 919         ret = help_handle_key (h, parm);
 920         if (ret == MSG_HANDLED)
 921             widget_draw (w);
 922 
 923         return ret;
 924     }
 925 
 926     case MSG_ACTION:
 927         // Handle shortcuts and buttonbar.
 928         return help_execute_cmd (parm);
 929 
 930     default:
 931         return dlg_default_callback (w, sender, msg, parm, data);
 932     }
 933 }
 934 
 935 /* --------------------------------------------------------------------------------------------- */
 936 
 937 static void
 938 interactive_display_finish (void)
     /*   */
 939 {
 940     clear_link_areas ();
 941 }
 942 
 943 /* --------------------------------------------------------------------------------------------- */
 944 /** translate help file into terminal encoding */
 945 
 946 static void
 947 translate_file (char *filedata)
     /*   */
 948 {
 949     GIConv conv;
 950 
 951     conv = str_crt_conv_from ("UTF-8");
 952     if (conv != INVALID_CONV)
 953     {
 954         GString *translated_data;
 955         gboolean nok;
 956 
 957         g_free (fdata);
 958 
 959         // initial allocation for largest whole help file
 960         translated_data = g_string_sized_new (32 * 1024);
 961         nok = (str_convert (conv, filedata, translated_data) == ESTR_FAILURE);
 962         fdata = g_string_free (translated_data, nok);
 963 
 964         str_close_conv (conv);
 965     }
 966 }
 967 
 968 /* --------------------------------------------------------------------------------------------- */
 969 
 970 static cb_ret_t
 971 md_callback (Widget *w, Widget *sender, widget_msg_t msg, int parm, void *data)
     /*   */
 972 {
 973     switch (msg)
 974     {
 975     case MSG_RESIZE:
 976         widget_default_callback (w, NULL, MSG_RESIZE, 0, data);
 977         w->rect.lines = help_lines;
 978         return MSG_HANDLED;
 979 
 980     default:
 981         return widget_default_callback (w, sender, msg, parm, data);
 982     }
 983 }
 984 
 985 /* --------------------------------------------------------------------------------------------- */
 986 
 987 static void
 988 help_mouse_callback (Widget *w, mouse_msg_t msg, mouse_event_t *event)
     /*   */
 989 {
 990     int x, y;
 991     GSList *current_area;
 992 
 993     if (msg != MSG_MOUSE_CLICK)
 994         return;
 995 
 996     if ((event->buttons & GPM_B_RIGHT) != 0)
 997     {
 998         // Right button click
 999         help_back (whelp);
1000         return;
1001     }
1002 
1003     // Left bytton click
1004 
1005     // The event is relative to the dialog window, adjust it:
1006     x = event->x - 1;
1007     y = event->y - 1;
1008 
1009     // Test whether the mouse click is inside one of the link areas
1010     for (current_area = link_area; current_area != NULL; current_area = g_slist_next (current_area))
1011     {
1012         Link_Area *la = (Link_Area *) current_area->data;
1013 
1014         // Test one line link area
1015         if (y == la->y1 && x >= la->x1 && y == la->y2 && x <= la->x2)
1016             break;
1017 
1018         // Test two line link area
1019         if (la->y1 + 1 == la->y2)
1020         {
1021             // The first line || The second line
1022             if ((y == la->y1 && x >= la->x1) || (y == la->y2 && x <= la->x2))
1023                 break;
1024         }
1025         // Mouse will not work with link areas of more than two lines
1026     }
1027 
1028     // Test whether a link area was found
1029     if (current_area != NULL)
1030     {
1031         Link_Area *la = (Link_Area *) current_area->data;
1032 
1033         // The click was inside a link area -> follow the link
1034         history_ptr = (history_ptr + 1) % HISTORY_SIZE;
1035         history[history_ptr].page = currentpoint;
1036         history[history_ptr].link = la->link_name;
1037         currentpoint = help_follow_link (currentpoint, la->link_name);
1038         selected_item = NULL;
1039     }
1040     else if (y < 0)
1041         move_backward (help_lines - 1);
1042     else if (y >= help_lines)
1043         move_forward (help_lines - 1);
1044     else if (y < help_lines / 2)
1045         move_backward (1);
1046     else
1047         move_forward (1);
1048 
1049     // Show the new node
1050     widget_draw (WIDGET (w->owner));
1051 }
1052 
1053 /* --------------------------------------------------------------------------------------------- */
1054 
1055 static Widget *
1056 mousedispatch_new (const WRect *r)
     /*   */
1057 {
1058     Widget *w;
1059 
1060     w = g_new0 (Widget, 1);
1061     widget_init (w, r, md_callback, help_mouse_callback);
1062     w->options |= WOP_SELECTABLE | WOP_WANT_CURSOR;
1063 
1064     return w;
1065 }
1066 
1067 /* --------------------------------------------------------------------------------------------- */
1068 /*** public functions ****************************************************************************/
1069 /* --------------------------------------------------------------------------------------------- */
1070 
1071 /* event callback */
1072 gboolean
1073 help_interactive_display (const gchar *event_group_name, const gchar *event_name,
     /*   */
1074                           gpointer init_data, gpointer data)
1075 {
1076     const dlg_colors_t help_colors = {
1077         HELP_NORMAL_COLOR,  // common text color
1078         0,                  // unused in help
1079         HELP_BOLD_COLOR,    // bold text color
1080         0,                  // unused in help
1081         HELP_TITLE_COLOR    // title color
1082     };
1083 
1084     Widget *wh;
1085     WGroup *g;
1086     WButtonBar *help_bar;
1087     Widget *md;
1088     char *hlpfile = NULL;
1089     char *filedata;
1090     ev_help_t *event_data = (ev_help_t *) data;
1091     WRect r = { 1, 1, 1, 1 };
1092     int i;
1093 
1094     (void) event_group_name;
1095     (void) event_name;
1096     (void) init_data;
1097 
1098     if (event_data->filename != NULL)
1099         g_file_get_contents (event_data->filename, &filedata, NULL, NULL);
1100     else
1101         filedata = load_mc_home_file (mc_global.share_data_dir, MC_HELP, &hlpfile, NULL);
1102 
1103     if (filedata == NULL)
1104         message (D_ERROR, MSG_ERROR, _ ("Cannot open file %s\n%s"),
1105                  event_data->filename ? event_data->filename : hlpfile, unix_error_string (errno));
1106 
1107     g_free (hlpfile);
1108 
1109     if (filedata == NULL)
1110         return TRUE;
1111 
1112     translate_file (filedata);
1113 
1114     g_free (filedata);
1115 
1116     if (fdata == NULL)
1117         return TRUE;
1118 
1119     if ((event_data->node == NULL) || (*event_data->node == '\0'))
1120         event_data->node = "[main]";
1121 
1122     main_node = search_string (fdata, event_data->node);
1123 
1124     if (main_node == NULL)
1125     {
1126         message (D_ERROR, MSG_ERROR, _ ("Cannot find node %s in help file"), event_data->node);
1127 
1128         // Fallback to [main], return if it also cannot be found
1129         main_node = search_string (fdata, "[main]");
1130         if (main_node == NULL)
1131         {
1132             interactive_display_finish ();
1133             return TRUE;
1134         }
1135     }
1136 
1137     help_lines = MIN (LINES - 4, MAX (2 * LINES / 3, 18));
1138 
1139     whelp = dlg_create (TRUE, 0, 0, help_lines + 4, HELP_WINDOW_WIDTH + 4, WPOS_CENTER | WPOS_TRYUP,
1140                         FALSE, help_colors, help_callback, NULL, "[Help]", _ ("Help"));
1141     wh = WIDGET (whelp);
1142     g = GROUP (whelp);
1143     wh->keymap = help_map;
1144     widget_want_tab (wh, TRUE);
1145     // draw background
1146     whelp->bg->callback = help_bg_callback;
1147 
1148     selected_item = search_string_node (main_node, STRING_LINK_START) - 1;
1149     currentpoint = main_node + 1;  // Skip the newline following the start of the node
1150 
1151     for (i = HISTORY_SIZE - 1; i >= 0; i--)
1152     {
1153         history[i].page = currentpoint;
1154         history[i].link = selected_item;
1155     }
1156 
1157     help_bar = buttonbar_new ();
1158     WIDGET (help_bar)->rect.y -= wh->rect.y;
1159     WIDGET (help_bar)->rect.x -= wh->rect.x;
1160 
1161     r.lines = help_lines;
1162     r.cols = HELP_WINDOW_WIDTH - 2;
1163     md = mousedispatch_new (&r);
1164 
1165     group_add_widget (g, md);
1166     group_add_widget (g, help_bar);  // FIXME
1167 
1168     buttonbar_set_label (help_bar, 1, Q_ ("ButtonBar|Help"), wh->keymap, NULL);
1169     buttonbar_set_label (help_bar, 2, Q_ ("ButtonBar|Index"), wh->keymap, NULL);
1170     buttonbar_set_label (help_bar, 3, Q_ ("ButtonBar|Prev"), wh->keymap, NULL);
1171     buttonbar_set_label (help_bar, 4, "", wh->keymap, NULL);
1172     buttonbar_set_label (help_bar, 5, "", wh->keymap, NULL);
1173     buttonbar_set_label (help_bar, 6, "", wh->keymap, NULL);
1174     buttonbar_set_label (help_bar, 7, "", wh->keymap, NULL);
1175     buttonbar_set_label (help_bar, 8, "", wh->keymap, NULL);
1176     buttonbar_set_label (help_bar, 9, "", wh->keymap, NULL);
1177     buttonbar_set_label (help_bar, 10, Q_ ("ButtonBar|Quit"), wh->keymap, NULL);
1178 
1179     dlg_run (whelp);
1180     interactive_display_finish ();
1181     widget_destroy (wh);
1182     return TRUE;
1183 }
1184 
1185 /* --------------------------------------------------------------------------------------------- */
/* */
root/src/help.c

DEFINITIONS
