session.c

gcc-2.95.3 Linux下最常用的C编译器

          /* Free the node structures which held onto internal node contents
             here.  This doesn't free the contents; we have a garbage collector
             which does that. */
          for (i = 0; info_win->nodes[i]; i++)
            if (internal_info_node_p (info_win->nodes[i]))
              free (info_win->nodes[i]);
          free (info_win->nodes);

          maybe_free (info_win->pagetops);
          maybe_free (info_win->points);
        }

      free (info_win);
    }
#if defined (DEBUG_FORGET_WINDOW_AND_NODES)
  consistency_check_info_windows ();
#endif /* DEBUG_FORGET_WINDOW_AND_NODES */
}

/* Set WINDOW to show NODE.  Remember the new window in our list of Info
   windows.  If we are doing automatic footnote display, also try to display
   the footnotes for this window. */
void
info_set_node_of_window (window, node)
     WINDOW *window;
     NODE *node;
{
  /* Put this node into the window. */
  window_set_node_of_window (window, node);

  /* Remember this node and window in our list of info windows. */
  remember_window_and_node (window, node);

  /* If doing auto-footnote display/undisplay, show the footnotes belonging
     to this window's node. */
  if (auto_footnotes_p)
    info_get_or_remove_footnotes (window);
}


/* **************************************************************** */
/*                                                                  */
/*                     Info Movement Commands                       */
/*                                                                  */
/* **************************************************************** */

/* Change the pagetop of WINDOW to DESIRED_TOP, perhaps scrolling the screen
   to do so. */
void
set_window_pagetop (window, desired_top)
     WINDOW *window;
     int desired_top;
{
  int point_line, old_pagetop;

  if (desired_top < 0)
    desired_top = 0;
  else if (desired_top > window->line_count)
    desired_top = window->line_count - 1;

  if (window->pagetop == desired_top)
    return;

  old_pagetop = window->pagetop;
  window->pagetop = desired_top;

  /* Make sure that point appears in this window. */
  point_line = window_line_of_point (window);
  if ((point_line < window->pagetop) ||
      ((point_line - window->pagetop) > window->height - 1))
    window->point =
      window->line_starts[window->pagetop] - window->node->contents;

  window->flags |= W_UpdateWindow;

  /* Find out which direction to scroll, and scroll the window in that
     direction.  Do this only if there would be a savings in redisplay
     time.  This is true if the amount to scroll is less than the height
     of the window, and if the number of lines scrolled would be greater
     than 10 % of the window's height. */
  if (old_pagetop < desired_top)
    {
      int start, end, amount;

      amount = desired_top - old_pagetop;

      if ((amount >= window->height) ||
          (((window->height - amount) * 10) < window->height))
        return;

      start = amount + window->first_row;
      end = window->height + window->first_row;

      display_scroll_display (start, end, -amount);
    }
  else
    {
      int start, end, amount;

      amount = old_pagetop - desired_top;

      if ((amount >= window->height) ||
          (((window->height - amount) * 10) < window->height))
        return;

      start = window->first_row;
      end = (window->first_row + window->height) - amount;
      display_scroll_display (start, end, amount);
    }
}

/* Immediately make WINDOW->point visible on the screen, and move the
   terminal cursor there. */
static void
info_show_point (window)
     WINDOW *window;
{
  int old_pagetop;

  old_pagetop = window->pagetop;
  window_adjust_pagetop (window);
  if (old_pagetop != window->pagetop)
    {
      int new_pagetop;

      new_pagetop = window->pagetop;
      window->pagetop = old_pagetop;
      set_window_pagetop (window, new_pagetop);
    }

  if (window->flags & W_UpdateWindow)
    display_update_one_window (window);

  display_cursor_at_point (window);
}

/* Move WINDOW->point from OLD line index to NEW line index. */
static void
move_to_new_line (old, new, window)
     int old, new;
     WINDOW *window;
{
  if (old == -1)
    {
      info_error (CANT_FIND_POINT);
    }
  else
    {
      int goal;

      if (new >= window->line_count || new < 0)
        return;

      goal = window_get_goal_column (window);
      window->goal_column = goal;

      window->point = window->line_starts[new] - window->node->contents;
      window->point += window_chars_to_goal (window->line_starts[new], goal);
      info_show_point (window);
    }
}

/* Move WINDOW's point down to the next line if possible. */
DECLARE_INFO_COMMAND (info_next_line, _("Move down to the next line"))
{
  int old_line, new_line;

  if (count < 0)
    info_prev_line (window, -count, key);
  else
    {
      old_line = window_line_of_point (window);
      new_line = old_line + count;
      move_to_new_line (old_line, new_line, window);
    }
}

/* Move WINDOW's point up to the previous line if possible. */
DECLARE_INFO_COMMAND (info_prev_line, _("Move up to the previous line"))
{
  int old_line, new_line;

  if (count < 0)
    info_next_line (window, -count, key);
  else
    {
      old_line = window_line_of_point (window);
      new_line = old_line - count;
      move_to_new_line (old_line, new_line, window);
    }
}

/* Move WINDOW's point to the end of the true line. */
DECLARE_INFO_COMMAND (info_end_of_line, _("Move to the end of the line"))
{
  register int point, len;
  register char *buffer;

  buffer = window->node->contents;
  len = window->node->nodelen;

  for (point = window->point;
       (point < len) && (buffer[point] != '\n');
       point++);

  if (point != window->point)
    {
      window->point = point;
      info_show_point (window);
    }
}

/* Move WINDOW's point to the beginning of the true line. */
DECLARE_INFO_COMMAND (info_beginning_of_line, _("Move to the start of the line"))
{
  register int point;
  register char *buffer;

  buffer = window->node->contents;
  point = window->point;

  for (; (point) && (buffer[point - 1] != '\n'); point--);

  /* If at a line start alreay, do nothing. */
  if (point != window->point)
    {
      window->point = point;
      info_show_point (window);
    }
}

/* Move point forward in the node. */
DECLARE_INFO_COMMAND (info_forward_char, _("Move forward a character"))
{
  if (count < 0)
    info_backward_char (window, -count, key);
  else
    {
      window->point += count;

      if (window->point >= window->node->nodelen)
        window->point = window->node->nodelen - 1;

      info_show_point (window);
    }
}

/* Move point backward in the node. */
DECLARE_INFO_COMMAND (info_backward_char, _("Move backward a character"))
{
  if (count < 0)
    info_forward_char (window, -count, key);
  else
    {
      window->point -= count;

      if (window->point < 0)
        window->point = 0;

      info_show_point (window);
    }
}

#define alphabetic(c) (islower (c) || isupper (c) || isdigit (c))

/* Move forward a word in this node. */
DECLARE_INFO_COMMAND (info_forward_word, _("Move forward a word"))
{
  long point;
  char *buffer;
  int end, c;

  if (count < 0)
    {
      info_backward_word (window, -count, key);
      return;
    }

  point = window->point;
  buffer = window->node->contents;
  end = window->node->nodelen;

  while (count)
    {
      if (point + 1 >= end)
        return;

      /* If we are not in a word, move forward until we are in one.
         Then, move forward until we hit a non-alphabetic character. */
      c = buffer[point];

      if (!alphabetic (c))
        {
          while (++point < end)
            {
              c = buffer[point];
              if (alphabetic (c))
                break;
            }
        }

      if (point >= end) return;

      while (++point < end)
        {
          c = buffer[point];
          if (!alphabetic (c))
            break;
        }
      --count;
    }
  window->point = point;
  info_show_point (window);
}

DECLARE_INFO_COMMAND (info_backward_word, _("Move backward a word"))
{
  long point;
  char *buffer;
  int c;

  if (count < 0)
    {
      info_forward_word (window, -count, key);
      return;
    }

  buffer = window->node->contents;
  point = window->point;

  while (count)
    {
      if (point == 0)
        break;

      /* Like info_forward_word (), except that we look at the
         characters just before point. */

      c = buffer[point - 1];

      if (!alphabetic (c))
        {
          while (--point)
            {
              c = buffer[point - 1];
              if (alphabetic (c))
                break;
            }
        }

      while (point)
        {
          c = buffer[point - 1];
          if (!alphabetic (c))
            break;
          else
            --point;
        }
      --count;
    }
  window->point = point;
  info_show_point (window);
}

/* Here is a list of time counter names which correspond to ordinal numbers.
   It is used to print "once" instead of "1". */
static char *counter_names[] = {
  "not at all", "once", "twice", "three", "four", "five", "six",
  (char *)NULL
};

/* Buffer used to return values from times_description (). */
static char td_buffer[50];

/* Function returns a static string fully describing the number of times
   present in COUNT. */
static char *
times_description (count)
     int count;
{
  register int i;

  td_buffer[0] = '\0';

  for (i = 0; counter_names[i]; i++)
    if (count == i)
      break;

  if (counter_names[i])
    sprintf (td_buffer, "%s%s", counter_names[i], count > 2 ? _(" times") : "");
  else
    sprintf (td_buffer, _("%d times"), count);

  return (td_buffer);
}

/* Variable controlling the behaviour of default scrolling when you are
   already at the bottom of a node.  Possible values are defined in session.h.
   The meanings are:

   IS_Continuous        Try to get first menu item, or failing that, the
                        "Next:" pointer, or failing that, the "Up:" and
                        "Next:" of the up.
   IS_NextOnly          Try to get "Next:" menu item.
   IS_PageOnly          Simply give up at the bottom of a node. */

int info_scroll_behaviour = IS_Continuous;

/* Choices used by the completer when reading a value for the user-visible
   variable "scroll-behaviour". */
char *info_scroll_choices[] = {
  "Continuous", "Next Only", "Page Only", (char *)NULL
};

/* Move to 1st menu item, Next, Up/Next, or error in this window. */
static void
forward_move_node_structure (window, behaviour)
     WINDOW *window;
     int behaviour;
{
  switch (behaviour)
    {
    case IS_PageOnly:
      info_error (AT_NODE_BOTTOM);
      break;

    case IS_NextOnly:
      info_next_label_of_node (window->node);
      if (!info_parsed_nodename && !info_parsed_filename)
        info_error (_("No \"Next\" pointer for this node."));
      else
        {
          window_message_in_echo_area (_("Following \"Next\" node..."));
          info_handle_pointer (_("Next"), window);
        }
      break;

    case IS_Continuous:
      {
        /* First things first.  If this node contains a menu, move down
           into the menu. */
        {
          REFERENCE **menu;

          menu = info_menu_of_node (window->node);

          if (menu)
            {
              info_free_references (menu);
              window_message_in_echo_area (_("Selecting first menu item..."));
              info_menu_digit (window, 1, '1');
              return;
            }
        }

        /* Okay, this node does not contain a menu.  If it contains a
           "Next:" pointer, use that. */
        info_next_label_of_node (window->node);
        if (info_label_was_found)
          {
            window_message_in_echo_area (_("Selecting \"Next\" node..."));
            info_handle_pointer (_("Next"), window);
            return;
          }