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_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) 1994-2019
   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 <http://www.gnu.org/licenses/>.
  21  */
  22 
  23 
  24 /** \file help.c
  25  *  \brief Source: hypertext file browser
  26  *
  27  *  Implements the hypertext file viewer.
  28  *  The hypertext file is a file that may have one or more nodes.  Each
  29  *  node ends with a ^D character and starts with a bracket, then the
  30  *  name of the node and then a closing bracket. Right after the closing
  31  *  bracket a newline is placed. This newline is not to be displayed by
  32  *  the help viewer and must be skipped - its sole purpose is to faciliate
  33  *  the work of the people managing the help file template (xnc.hlp) .
  34  *
  35  *  Links in the hypertext file are specified like this: the text that
  36  *  will be highlighted should have a leading ^A, then it comes the
  37  *  text, then a ^B indicating that highlighting is done, then the name
  38  *  of the node you want to link to and then a ^C.
  39  *
  40  *  The file must contain a ^D at the beginning and at the end of the
  41  *  file or the program will not be able to detect the end of file.
  42  *
  43  *  Lazyness/widgeting attack: This file does use the dialog manager
  44  *  and uses mainly the dialog to achieve the help work.  there is only
  45  *  one specialized widget and it's only used to forward the mouse messages
  46  *  to the appropriate routine.
  47  */
  48 
  49 
  50 #include <config.h>
  51 
  52 #include <errno.h>
  53 #include <limits.h>             /* MB_LEN_MAX */
  54 #include <stdio.h>
  55 #include <sys/types.h>
  56 #include <sys/stat.h>
  57 
  58 #include "lib/global.h"
  59 
  60 #include "lib/tty/tty.h"
  61 #include "lib/skin.h"
  62 #include "lib/strutil.h"
  63 #include "lib/fileloc.h"
  64 #include "lib/util.h"
  65 #include "lib/widget.h"
  66 #include "lib/event-types.h"
  67 
  68 #include "keybind-defaults.h"
  69 #include "help.h"
  70 
  71 /*** global variables ****************************************************************************/
  72 
  73 /*** file scope macro definitions ****************************************************************/
  74 
  75 #define MAXLINKNAME 80
  76 #define HISTORY_SIZE 20
  77 #define HELP_WINDOW_WIDTH MIN(80, COLS - 16)
  78 
  79 #define STRING_LINK_START       "\01"
  80 #define STRING_LINK_POINTER     "\02"
  81 #define STRING_LINK_END         "\03"
  82 #define STRING_NODE_END         "\04"
  83 
  84 /*** file scope type declarations ****************************************************************/
  85 
  86 /* Link areas for the mouse */
  87 typedef struct Link_Area
  88 {
  89     int x1, y1, x2, y2;
  90     const char *link_name;
  91 } Link_Area;
  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;         /* 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 static cb_ret_t help_callback (Widget * w, Widget * sender, widget_msg_t msg, int parm, void *data);
 117 
 118 /*** file scope functions ************************************************************************/
 119 /* --------------------------------------------------------------------------------------------- */
 120 
 121 /** returns the position where text was found in the start buffer 
 122  * or 0 if not found
 123  */
 124 static const char *
 125 search_string (const char *start, const char *text)
     /*   */
 126 {
 127     const char *result = NULL;
 128     char *local_text = g_strdup (text);
 129     char *d = local_text;
 130     const char *e = start;
 131 
 132     /* fmt sometimes replaces a space with a newline in the help file */
 133     /* Replace the newlines in the link name with spaces to correct the situation */
 134     while (*d != '\0')
 135     {
 136         if (*d == '\n')
 137             *d = ' ';
 138         str_next_char (&d);
 139     }
 140 
 141     /* Do search */
 142     for (d = local_text; *e; e++)
 143     {
 144         if (*d == *e)
 145             d++;
 146         else
 147             d = local_text;
 148         if (*d == '\0')
 149         {
 150             result = e + 1;
 151             break;
 152         }
 153     }
 154 
 155     g_free (local_text);
 156     return result;
 157 }
 158 
 159 /* --------------------------------------------------------------------------------------------- */
 160 /** Searches text in the buffer pointed by start.  Search ends
 161  * if the CHAR_NODE_END is found in the text.
 162  * @return NULL on failure
 163  */
 164 
 165 static const char *
 166 search_string_node (const char *start, const char *text)
     /*   */
 167 {
 168     const char *d = text;
 169     const char *e = start;
 170 
 171     if (start != NULL)
 172         for (; *e && *e != CHAR_NODE_END; e++)
 173         {
 174             if (*d == *e)
 175                 d++;
 176             else
 177                 d = text;
 178             if (*d == '\0')
 179                 return e + 1;
 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 && *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; *p != CHAR_LINK_END && *p && *p != CHAR_NODE_END && i < MAXLINKNAME - 3;)
 312             link_name[i++] = *++p;
 313         link_name[i - 1] = ']';
 314         link_name[i] = '\0';
 315         p = search_string (fdata, link_name);
 316         if (p != NULL)
 317         {
 318             p += 1;             /* Skip the newline following the start of the node */
 319             return p;
 320         }
 321     }
 322 
 323     /* Create a replacement page with the error message */
 324     return _("Help file format error\n");
 325 }
 326 
 327 /* --------------------------------------------------------------------------------------------- */
 328 
 329 static const char *
 330 select_next_link (const char *current_link)
     /*   */
 331 {
 332     const char *p;
 333 
 334     if (current_link == NULL)
 335         return NULL;
 336 
 337     p = search_string_node (current_link, STRING_LINK_END);
 338     if (p == NULL)
 339         return NULL;
 340     p = search_string_node (p, STRING_LINK_START);
 341     if (p == NULL)
 342         return NULL;
 343     return p - 1;
 344 }
 345 
 346 /* --------------------------------------------------------------------------------------------- */
 347 
 348 static const char *
 349 select_prev_link (const char *current_link)
     /*   */
 350 {
 351     return current_link == NULL ? NULL : search_char_node (current_link - 1, CHAR_LINK_START, -1);
 352 }
 353 
 354 /* --------------------------------------------------------------------------------------------- */
 355 
 356 static void
 357 start_link_area (int x, int y, const char *link_name)
     /*   */
 358 {
 359     Link_Area *la;
 360 
 361     if (inside_link_area)
 362         message (D_NORMAL, _("Warning"), "%s", _("Internal bug: Double start of link area"));
 363 
 364     /* Allocate memory for a new link area */
 365     la = g_new (Link_Area, 1);
 366     /* Save the beginning coordinates of the link area */
 367     la->x1 = x;
 368     la->y1 = y;
 369     /* Save the name of the destination anchor */
 370     la->link_name = link_name;
 371     link_area = g_slist_prepend (link_area, la);
 372 
 373     inside_link_area = TRUE;
 374 }
 375 
 376 /* --------------------------------------------------------------------------------------------- */
 377 
 378 static void
 379 end_link_area (int x, int y)
     /*   */
 380 {
 381     if (inside_link_area)
 382     {
 383         Link_Area *la = (Link_Area *) link_area->data;
 384         /* Save the end coordinates of the link area */
 385         la->x2 = x;
 386         la->y2 = y;
 387         inside_link_area = FALSE;
 388     }
 389 }
 390 
 391 /* --------------------------------------------------------------------------------------------- */
 392 
 393 static void
 394 clear_link_areas (void)
     /*   */
 395 {
 396     g_slist_free_full (link_area, g_free);
 397     link_area = NULL;
 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_move (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     const char *p, *n;
 451     int col, line, c;
 452     gboolean painting = TRUE;
 453     gboolean acs;               /* Flag: Alternate character set active? */
 454     gboolean repeat_paint;
 455     int active_col, active_line;        /* Active link position */
 456     char buff[MB_LEN_MAX + 1];
 457     GString *word;
 458 
 459     word = g_string_sized_new (32);
 460 
 461     tty_setcolor (HELP_NORMAL_COLOR);
 462     do
 463     {
 464         line = col = active_col = active_line = 0;
 465         repeat_paint = FALSE;
 466         acs = FALSE;
 467 
 468         clear_link_areas ();
 469         if ((int) (selected_item - paint_start) < 0)
 470             selected_item = NULL;
 471 
 472         p = paint_start;
 473         n = paint_start;
 474         while ((n[0] != '\0') && (n[0] != CHAR_NODE_END) && (line < help_lines))
 475         {
 476             p = n;
 477             n = str_cget_next_char (p);
 478             memcpy (buff, p, n - p);
 479             buff[n - p] = '\0';
 480 
 481             c = (unsigned char) buff[0];
 482             switch (c)
 483             {
 484             case CHAR_LINK_START:
 485                 if (selected_item == NULL)
 486                     selected_item = p;
 487                 if (p != selected_item)
 488                     tty_setcolor (HELP_LINK_COLOR);
 489                 else
 490                 {
 491                     tty_setcolor (HELP_SLINK_COLOR);
 492 
 493                     /* Store the coordinates of the link */
 494                     active_col = col + 2;
 495                     active_line = line + 2;
 496                 }
 497                 start_link_area (col, line, p);
 498                 break;
 499             case CHAR_LINK_POINTER:
 500                 painting = FALSE;
 501                 break;
 502             case CHAR_LINK_END:
 503                 painting = TRUE;
 504                 help_print_word (h, word, &col, &line, FALSE);
 505                 end_link_area (col - 1, line);
 506                 tty_setcolor (HELP_NORMAL_COLOR);
 507                 break;
 508             case CHAR_ALTERNATE:
 509                 acs = TRUE;
 510                 break;
 511             case CHAR_NORMAL:
 512                 acs = FALSE;
 513                 break;
 514             case CHAR_VERSION:
 515                 widget_move (h, line + 2, col + 2);
 516                 tty_print_string (VERSION);
 517                 col += str_term_width1 (VERSION);
 518                 break;
 519             case CHAR_FONT_BOLD:
 520                 tty_setcolor (HELP_BOLD_COLOR);
 521                 break;
 522             case CHAR_FONT_ITALIC:
 523                 tty_setcolor (HELP_ITALIC_COLOR);
 524                 break;
 525             case CHAR_FONT_NORMAL:
 526                 help_print_word (h, word, &col, &line, FALSE);
 527                 tty_setcolor (HELP_NORMAL_COLOR);
 528                 break;
 529             case '\n':
 530                 if (painting)
 531                     help_print_word (h, word, &col, &line, FALSE);
 532                 line++;
 533                 col = 0;
 534                 break;
 535             case ' ':
 536             case '\t':
 537                 /* word delimiter */
 538                 if (painting)
 539                 {
 540                     help_print_word (h, word, &col, &line, c == ' ');
 541                     if (c == '\t')
 542                     {
 543                         col = (col / 8 + 1) * 8;
 544                         if (col >= HELP_WINDOW_WIDTH)
 545                         {
 546                             line++;
 547                             col = 8;
 548                         }
 549                     }
 550                 }
 551                 break;
 552             default:
 553                 if (painting && (line < help_lines))
 554                 {
 555                     if (!acs)
 556                         /* accumulate symbols in a word */
 557                         g_string_append (word, buff);
 558                     else if (col < HELP_WINDOW_WIDTH)
 559                     {
 560                         widget_move (h, line + 2, col + 2);
 561 
 562                         if ((c == ' ') || (c == '.'))
 563                             tty_print_char (c);
 564                         else
 565 #ifndef HAVE_SLANG
 566                             tty_print_char (acs_map[c]);
 567 #else
 568                             SLsmg_draw_object (WIDGET (h)->y + line + 2, WIDGET (h)->x + col + 2,
 569                                                c);
 570 #endif
 571                         col++;
 572                     }
 573                 }
 574             }
 575         }
 576 
 577         /* print last word */
 578         if (n[0] == CHAR_NODE_END)
 579             help_print_word (h, word, &col, &line, FALSE);
 580 
 581         last_shown = p;
 582         end_of_node = line < help_lines;
 583         tty_setcolor (HELP_NORMAL_COLOR);
 584         if ((int) (selected_item - last_shown) >= 0)
 585         {
 586             if ((link_area == NULL) || (link_area->data == NULL))
 587                 selected_item = NULL;
 588             else
 589             {
 590                 selected_item = ((Link_Area *) link_area->data)->link_name;
 591                 repeat_paint = TRUE;
 592             }
 593         }
 594     }
 595     while (repeat_paint);
 596 
 597     g_string_free (word, TRUE);
 598 
 599     /* Position the cursor over a nice link */
 600     if (active_col)
 601         widget_move (h, active_line, active_col);
 602 }
 603 
 604 /* --------------------------------------------------------------------------------------------- */
 605 /** show help */
 606 
 607 static void
 608 help_help (WDialog * h)
     /*   */
 609 {
 610     const char *p;
 611 
 612     history_ptr = (history_ptr + 1) % HISTORY_SIZE;
 613     history[history_ptr].page = currentpoint;
 614     history[history_ptr].link = selected_item;
 615 
 616     p = search_string (fdata, "[How to use help]");
 617     if (p != NULL)
 618     {
 619         currentpoint = p + 1;   /* Skip the newline following the start of the node */
 620         selected_item = NULL;
 621         send_message (h, NULL, MSG_DRAW, 0, NULL);
 622     }
 623 }
 624 
 625 /* --------------------------------------------------------------------------------------------- */
 626 
 627 static void
 628 help_index (WDialog * h)
     /*   */
 629 {
 630     const char *new_item;
 631 
 632     new_item = search_string (fdata, "[Contents]");
 633 
 634     if (new_item == NULL)
 635         message (D_ERROR, MSG_ERROR, _("Cannot find node %s in help file"), "[Contents]");
 636     else
 637     {
 638         history_ptr = (history_ptr + 1) % HISTORY_SIZE;
 639         history[history_ptr].page = currentpoint;
 640         history[history_ptr].link = selected_item;
 641 
 642         currentpoint = new_item + 1;    /* Skip the newline following the start of the node */
 643         selected_item = NULL;
 644         send_message (h, NULL, MSG_DRAW, 0, NULL);
 645     }
 646 }
 647 
 648 /* --------------------------------------------------------------------------------------------- */
 649 
 650 static void
 651 help_back (WDialog * h)
     /*   */
 652 {
 653     currentpoint = history[history_ptr].page;
 654     selected_item = history[history_ptr].link;
 655     history_ptr--;
 656     if (history_ptr < 0)
 657         history_ptr = HISTORY_SIZE - 1;
 658 
 659     send_message (h, NULL, MSG_DRAW, 0, NULL);  /* FIXME: unneeded? */
 660 }
 661 
 662 /* --------------------------------------------------------------------------------------------- */
 663 
 664 static void
 665 help_next_link (gboolean move_down)
     /*   */
 666 {
 667     const char *new_item;
 668 
 669     new_item = select_next_link (selected_item);
 670     if (new_item != NULL)
 671     {
 672         selected_item = new_item;
 673         if ((int) (selected_item - last_shown) >= 0)
 674         {
 675             if (move_down)
 676                 move_forward (1);
 677             else
 678                 selected_item = NULL;
 679         }
 680     }
 681     else if (move_down)
 682         move_forward (1);
 683     else
 684         selected_item = NULL;
 685 }
 686 
 687 /* --------------------------------------------------------------------------------------------- */
 688 
 689 static void
 690 help_prev_link (gboolean move_up)
     /*   */
 691 {
 692     const char *new_item;
 693 
 694     new_item = select_prev_link (selected_item);
 695     selected_item = new_item;
 696     if ((selected_item == NULL) || (selected_item < currentpoint))
 697     {
 698         if (move_up)
 699             move_backward (1);
 700         else if ((link_area != NULL) && (link_area->data != NULL))
 701             selected_item = ((Link_Area *) link_area->data)->link_name;
 702         else
 703             selected_item = NULL;
 704     }
 705 }
 706 
 707 /* --------------------------------------------------------------------------------------------- */
 708 
 709 static void
 710 help_next_node (void)
     /*   */
 711 {
 712     const char *new_item;
 713 
 714     new_item = currentpoint;
 715     while ((*new_item != '\0') && (*new_item != CHAR_NODE_END))
 716         new_item++;
 717 
 718     if (*++new_item == '[')
 719         while (*++new_item != '\0')
 720             if ((*new_item == ']') && (*++new_item != '\0') && (*++new_item != '\0'))
 721             {
 722                 currentpoint = new_item;
 723                 selected_item = NULL;
 724                 break;
 725             }
 726 }
 727 
 728 /* --------------------------------------------------------------------------------------------- */
 729 
 730 static void
 731 help_prev_node (void)
     /*   */
 732 {
 733     const char *new_item;
 734 
 735     new_item = currentpoint;
 736     while (((int) (new_item - fdata) > 1) && (*new_item != CHAR_NODE_END))
 737         new_item--;
 738     new_item--;
 739     while (((int) (new_item - fdata) > 0) && (*new_item != CHAR_NODE_END))
 740         new_item--;
 741     while (*new_item != ']')
 742         new_item++;
 743     currentpoint = new_item + 2;
 744     selected_item = NULL;
 745 }
 746 
 747 /* --------------------------------------------------------------------------------------------- */
 748 
 749 static void
 750 help_select_link (void)
     /*   */
 751 {
 752     /* follow link */
 753     if (selected_item == NULL)
 754     {
 755 #ifdef WE_WANT_TO_GO_BACKWARD_ON_KEY_RIGHT
 756         /* Is there any reason why the right key would take us
 757          * backward if there are no links selected?, I agree
 758          * with Torben than doing nothing in this case is better
 759          */
 760         /* If there are no links, go backward in history */
 761         history_ptr--;
 762         if (history_ptr < 0)
 763             history_ptr = HISTORY_SIZE - 1;
 764 
 765         currentpoint = history[history_ptr].page;
 766         selected_item = history[history_ptr].link;
 767 #endif
 768     }
 769     else
 770     {
 771         history_ptr = (history_ptr + 1) % HISTORY_SIZE;
 772         history[history_ptr].page = currentpoint;
 773         history[history_ptr].link = selected_item;
 774         currentpoint = help_follow_link (currentpoint, selected_item);
 775     }
 776 
 777     selected_item = NULL;
 778 }
 779 
 780 /* --------------------------------------------------------------------------------------------- */
 781 
 782 static cb_ret_t
 783 help_execute_cmd (long command)
     /*   */
 784 {
 785     cb_ret_t ret = MSG_HANDLED;
 786 
 787     switch (command)
 788     {
 789     case CK_Help:
 790         help_help (whelp);
 791         break;
 792     case CK_Index:
 793         help_index (whelp);
 794         break;
 795     case CK_Back:
 796         help_back (whelp);
 797         break;
 798     case CK_Up:
 799         help_prev_link (TRUE);
 800         break;
 801     case CK_Down:
 802         help_next_link (TRUE);
 803         break;
 804     case CK_PageDown:
 805         move_forward (help_lines - 1);
 806         break;
 807     case CK_PageUp:
 808         move_backward (help_lines - 1);
 809         break;
 810     case CK_HalfPageDown:
 811         move_forward (help_lines / 2);
 812         break;
 813     case CK_HalfPageUp:
 814         move_backward (help_lines / 2);
 815         break;
 816     case CK_Top:
 817         move_to_top ();
 818         break;
 819     case CK_Bottom:
 820         move_to_bottom ();
 821         break;
 822     case CK_Enter:
 823         help_select_link ();
 824         break;
 825     case CK_LinkNext:
 826         help_next_link (FALSE);
 827         break;
 828     case CK_LinkPrev:
 829         help_prev_link (FALSE);
 830         break;
 831     case CK_NodeNext:
 832         help_next_node ();
 833         break;
 834     case CK_NodePrev:
 835         help_prev_node ();
 836         break;
 837     case CK_Quit:
 838         dlg_stop (whelp);
 839         break;
 840     default:
 841         ret = MSG_NOT_HANDLED;
 842     }
 843 
 844     return ret;
 845 }
 846 
 847 /* --------------------------------------------------------------------------------------------- */
 848 
 849 static cb_ret_t
 850 help_handle_key (WDialog * h, int c)
     /*   */
 851 {
 852     long command;
 853 
 854     command = keybind_lookup_keymap_command (help_map, c);
 855     if ((command == CK_IgnoreKey) || (help_execute_cmd (command) == MSG_NOT_HANDLED))
 856         return MSG_NOT_HANDLED;
 857 
 858     send_message (h, NULL, MSG_DRAW, 0, NULL);
 859     return MSG_HANDLED;
 860 }
 861 
 862 /* --------------------------------------------------------------------------------------------- */
 863 
 864 static cb_ret_t
 865 help_callback (Widget * w, Widget * sender, widget_msg_t msg, int parm, void *data)
     /*   */
 866 {
 867     WDialog *h = DIALOG (w);
 868 
 869     switch (msg)
 870     {
 871     case MSG_RESIZE:
 872         {
 873             WButtonBar *bb;
 874 
 875             help_lines = MIN (LINES - 4, MAX (2 * LINES / 3, 18));
 876             dlg_set_size (h, help_lines + 4, HELP_WINDOW_WIDTH + 4);
 877             bb = find_buttonbar (h);
 878             widget_set_size (WIDGET (bb), LINES - 1, 0, 1, COLS);
 879             return MSG_HANDLED;
 880         }
 881 
 882     case MSG_DRAW:
 883         dlg_default_repaint (h);
 884         help_show (h, currentpoint);
 885         return MSG_HANDLED;
 886 
 887     case MSG_KEY:
 888         return help_handle_key (h, parm);
 889 
 890     case MSG_ACTION:
 891         /* Handle shortcuts and buttonbar. */
 892         return help_execute_cmd (parm);
 893 
 894     default:
 895         return dlg_default_callback (w, sender, msg, parm, data);
 896     }
 897 }
 898 
 899 /* --------------------------------------------------------------------------------------------- */
 900 
 901 static void
 902 interactive_display_finish (void)
     /*   */
 903 {
 904     clear_link_areas ();
 905 }
 906 
 907 /* --------------------------------------------------------------------------------------------- */
 908 /** translate help file into terminal encoding */
 909 
 910 static void
 911 translate_file (char *filedata)
     /*   */
 912 {
 913     GIConv conv;
 914     GString *translated_data;
 915 
 916     /* initial allocation for largest whole help file */
 917     translated_data = g_string_sized_new (32 * 1024);
 918 
 919     conv = str_crt_conv_from ("UTF-8");
 920 
 921     if (conv == INVALID_CONV)
 922         g_string_free (translated_data, TRUE);
 923     else
 924     {
 925         g_free (fdata);
 926 
 927         if (str_convert (conv, filedata, translated_data) != ESTR_FAILURE)
 928             fdata = g_string_free (translated_data, FALSE);
 929         else
 930         {
 931             fdata = NULL;
 932             g_string_free (translated_data, TRUE);
 933         }
 934         str_close_conv (conv);
 935     }
 936 }
 937 
 938 /* --------------------------------------------------------------------------------------------- */
 939 
 940 static cb_ret_t
 941 md_callback (Widget * w, Widget * sender, widget_msg_t msg, int parm, void *data)
     /*   */
 942 {
 943     switch (msg)
 944     {
 945     case MSG_RESIZE:
 946         w->lines = help_lines;
 947         return MSG_HANDLED;
 948 
 949     default:
 950         return widget_default_callback (w, sender, msg, parm, data);
 951     }
 952 }
 953 
 954 /* --------------------------------------------------------------------------------------------- */
 955 
 956 static void
 957 help_mouse_callback (Widget * w, mouse_msg_t msg, mouse_event_t * event)
     /*   */
 958 {
 959     int x, y;
 960     GSList *current_area;
 961 
 962     if (msg != MSG_MOUSE_CLICK)
 963         return;
 964 
 965     if ((event->buttons & GPM_B_RIGHT) != 0)
 966     {
 967         /* Right button click */
 968         help_back (whelp);
 969         return;
 970     }
 971 
 972     /* Left bytton click */
 973 
 974     /* The event is relative to the dialog window, adjust it: */
 975     x = event->x - 1;
 976     y = event->y - 1;
 977 
 978     /* Test whether the mouse click is inside one of the link areas */
 979     for (current_area = link_area; current_area != NULL; current_area = g_slist_next (current_area))
 980     {
 981         Link_Area *la = (Link_Area *) current_area->data;
 982 
 983         /* Test one line link area */
 984         if (y == la->y1 && x >= la->x1 && y == la->y2 && x <= la->x2)
 985             break;
 986 
 987         /* Test two line link area */
 988         if (la->y1 + 1 == la->y2)
 989         {
 990             /* The first line || The second line */
 991             if ((y == la->y1 && x >= la->x1) || (y == la->y2 && x <= la->x2))
 992                 break;
 993         }
 994         /* Mouse will not work with link areas of more than two lines */
 995     }
 996 
 997     /* Test whether a link area was found */
 998     if (current_area != NULL)
 999     {
1000         Link_Area *la = (Link_Area *) current_area->data;
1001 
1002         /* The click was inside a link area -> follow the link */
1003         history_ptr = (history_ptr + 1) % HISTORY_SIZE;
1004         history[history_ptr].page = currentpoint;
1005         history[history_ptr].link = la->link_name;
1006         currentpoint = help_follow_link (currentpoint, la->link_name);
1007         selected_item = NULL;
1008     }
1009     else if (y < 0)
1010         move_backward (help_lines - 1);
1011     else if (y >= help_lines)
1012         move_forward (help_lines - 1);
1013     else if (y < help_lines / 2)
1014         move_backward (1);
1015     else
1016         move_forward (1);
1017 
1018     /* Show the new node */
1019     send_message (w->owner, NULL, MSG_DRAW, 0, NULL);
1020 }
1021 
1022 /* --------------------------------------------------------------------------------------------- */
1023 
1024 static Widget *
1025 mousedispatch_new (int y, int x, int yl, int xl)
     /*   */
1026 {
1027     Widget *w;
1028 
1029     w = g_new0 (Widget, 1);
1030     widget_init (w, y, x, yl, xl, md_callback, help_mouse_callback);
1031     w->options |= WOP_SELECTABLE | WOP_WANT_CURSOR;
1032 
1033     return w;
1034 }
1035 
1036 /* --------------------------------------------------------------------------------------------- */
1037 /*** public functions ****************************************************************************/
1038 /* --------------------------------------------------------------------------------------------- */
1039 
1040 /* event callback */
1041 gboolean
1042 help_interactive_display (const gchar * event_group_name, const gchar * event_name,
     /*   */
1043                           gpointer init_data, gpointer data)
1044 {
1045     const dlg_colors_t help_colors = {
1046         HELP_NORMAL_COLOR,      /* common text color */
1047         0,                      /* unused in help */
1048         HELP_BOLD_COLOR,        /* bold text color */
1049         0,                      /* unused in help */
1050         HELP_TITLE_COLOR        /* title color */
1051     };
1052 
1053     WButtonBar *help_bar;
1054     Widget *md;
1055     char *hlpfile = NULL;
1056     char *filedata;
1057     ev_help_t *event_data = (ev_help_t *) data;
1058 
1059     (void) event_group_name;
1060     (void) event_name;
1061     (void) init_data;
1062 
1063     if (event_data->filename != NULL)
1064         g_file_get_contents (event_data->filename, &filedata, NULL, NULL);
1065     else
1066         filedata = load_mc_home_file (mc_global.share_data_dir, MC_HELP, &hlpfile, NULL);
1067 
1068     if (filedata == NULL)
1069         message (D_ERROR, MSG_ERROR, _("Cannot open file %s\n%s"),
1070                  event_data->filename ? event_data->filename : hlpfile, unix_error_string (errno));
1071 
1072     g_free (hlpfile);
1073 
1074     if (filedata == NULL)
1075         return TRUE;
1076 
1077     translate_file (filedata);
1078 
1079     g_free (filedata);
1080 
1081     if (fdata == NULL)
1082         return TRUE;
1083 
1084     if ((event_data->node == NULL) || (*event_data->node == '\0'))
1085         event_data->node = "[main]";
1086 
1087     main_node = search_string (fdata, event_data->node);
1088 
1089     if (main_node == NULL)
1090     {
1091         message (D_ERROR, MSG_ERROR, _("Cannot find node %s in help file"), event_data->node);
1092 
1093         /* Fallback to [main], return if it also cannot be found */
1094         main_node = search_string (fdata, "[main]");
1095         if (main_node == NULL)
1096         {
1097             interactive_display_finish ();
1098             return TRUE;
1099         }
1100     }
1101 
1102     help_lines = MIN (LINES - 4, MAX (2 * LINES / 3, 18));
1103 
1104     whelp =
1105         dlg_create (TRUE, 0, 0, help_lines + 4, HELP_WINDOW_WIDTH + 4, WPOS_CENTER | WPOS_TRYUP,
1106                     FALSE, help_colors, help_callback, NULL, "[Help]", _("Help"));
1107     widget_want_tab (WIDGET (whelp), TRUE);
1108 
1109     selected_item = search_string_node (main_node, STRING_LINK_START) - 1;
1110     currentpoint = main_node + 1;       /* Skip the newline following the start of the node */
1111 
1112     for (history_ptr = HISTORY_SIZE; history_ptr;)
1113     {
1114         history_ptr--;
1115         history[history_ptr].page = currentpoint;
1116         history[history_ptr].link = selected_item;
1117     }
1118 
1119     help_bar = buttonbar_new (TRUE);
1120     WIDGET (help_bar)->y -= WIDGET (whelp)->y;
1121     WIDGET (help_bar)->x -= WIDGET (whelp)->x;
1122 
1123     md = mousedispatch_new (1, 1, help_lines, HELP_WINDOW_WIDTH - 2);
1124 
1125     add_widget (whelp, md);
1126     add_widget (whelp, help_bar);
1127 
1128     buttonbar_set_label (help_bar, 1, Q_ ("ButtonBar|Help"), help_map, NULL);
1129     buttonbar_set_label (help_bar, 2, Q_ ("ButtonBar|Index"), help_map, NULL);
1130     buttonbar_set_label (help_bar, 3, Q_ ("ButtonBar|Prev"), help_map, NULL);
1131     buttonbar_set_label (help_bar, 4, "", help_map, NULL);
1132     buttonbar_set_label (help_bar, 5, "", help_map, NULL);
1133     buttonbar_set_label (help_bar, 6, "", help_map, NULL);
1134     buttonbar_set_label (help_bar, 7, "", help_map, NULL);
1135     buttonbar_set_label (help_bar, 8, "", help_map, NULL);
1136     buttonbar_set_label (help_bar, 9, "", help_map, NULL);
1137     buttonbar_set_label (help_bar, 10, Q_ ("ButtonBar|Quit"), help_map, NULL);
1138 
1139     dlg_run (whelp);
1140     interactive_display_finish ();
1141     dlg_destroy (whelp);
1142     return TRUE;
1143 }
1144 
1145 /* --------------------------------------------------------------------------------------------- */
/* */
root/src/help.c

DEFINITIONS
