echo-area.c

gcc-2.95.3 Linux下最常用的C编译器

   then transpose the characters before point. */
DECLARE_INFO_COMMAND (ea_transpose_chars, _("Transpose characters at point"))
{
  /* Handle conditions that would make it impossible to transpose
     characters. */
  if (!count || !input_line_point || (input_line_end - input_line_beg) < 2)
    return;

  while (count)
    {
      int t;
      if (input_line_point == input_line_end)
        {
          t = input_line[input_line_point - 1];

          input_line[input_line_point - 1] = input_line[input_line_point - 2];
          input_line[input_line_point - 2] = t;
        }
      else
        {
          t = input_line[input_line_point];

          input_line[input_line_point] = input_line[input_line_point - 1];
          input_line[input_line_point - 1] = t;

          if (count < 0 && input_line_point != input_line_beg)
            input_line_point--;
          else
            input_line_point++;
        }

      if (count < 0)
        count++;
      else
        count--;
    }
}

/* **************************************************************** */
/*                                                                  */
/*                   Echo Area Killing and Yanking                  */
/*                                                                  */
/* **************************************************************** */

static char **kill_ring = (char **)NULL;
static int kill_ring_index = 0; /* Number of kills appearing in KILL_RING. */
static int kill_ring_slots = 0; /* Number of slots allocated to KILL_RING. */
static int kill_ring_loc = 0;   /* Location of current yank pointer. */

/* The largest number of kills that we remember at one time. */
static int max_retained_kills = 15;

DECLARE_INFO_COMMAND (ea_yank, _("Yank back the contents of the last kill"))
{
  register int i;
  register char *text;

  if (!kill_ring_index)
    {
      inform_in_echo_area (_("Kill ring is empty"));
      return;
    }

  text = kill_ring[kill_ring_loc];

  for (i = 0; text[i]; i++)
    ea_insert (window, 1, text[i]);
}

/* If the last command was yank, or yank_pop, and the text just before
   point is identical to the current kill item, then delete that text
   from the line, rotate the index down, and yank back some other text. */
DECLARE_INFO_COMMAND (ea_yank_pop, _("Yank back a previous kill"))
{
  register int len;

  if (((ea_last_executed_command != ea_yank) &&
       (ea_last_executed_command != ea_yank_pop)) ||
      (kill_ring_index == 0))
    return;

  len = strlen (kill_ring[kill_ring_loc]);

  /* Delete the last yanked item from the line. */
  {
    register int i, counter;

    counter = input_line_end - input_line_point;
    
    for (i = input_line_point - len; counter; i++, counter--)
      input_line[i] = input_line[i + len];

    input_line_end -= len;
    input_line_point -= len;
  }

  /* Get a previous kill, and yank that. */
  kill_ring_loc--;
  if (kill_ring_loc < 0)
    kill_ring_loc = kill_ring_index - 1;

  ea_yank (window, count, key);
}

/* Delete the text from point to end of line. */
DECLARE_INFO_COMMAND (ea_kill_line, _("Kill to the end of the line"))
{
  if (count < 0)
    {
      ea_kill_text (input_line_point, input_line_beg);
      input_line_point = input_line_beg;
    }
  else
    ea_kill_text (input_line_point, input_line_end);
}

/* Delete the text from point to beg of line. */
DECLARE_INFO_COMMAND (ea_backward_kill_line,
                      _("Kill to the beginning of the line"))
{
  if (count < 0)
    ea_kill_text (input_line_point, input_line_end);
  else
    {
      ea_kill_text (input_line_point, input_line_beg);
      input_line_point = input_line_beg;
    }
}

/* Delete from point to the end of the current word. */
DECLARE_INFO_COMMAND (ea_kill_word, _("Kill the word following the cursor"))
{
  int orig_point = input_line_point;

  if (count < 0)
    ea_backward_kill_word (window, -count, key);
  else
    {
      ea_forward_word (window, count, key);

      if (input_line_point != orig_point)
        ea_kill_text (orig_point, input_line_point);

      input_line_point = orig_point;
    }
}

/* Delete from point to the start of the current word. */
DECLARE_INFO_COMMAND (ea_backward_kill_word,
                      _("Kill the word preceding the cursor"))
{
  int orig_point = input_line_point;

  if (count < 0)
    ea_kill_word (window, -count, key);
  else
    {
      ea_backward_word (window, count, key);

      if (input_line_point != orig_point)
        ea_kill_text (orig_point, input_line_point);
    }
}

/* The way to kill something.  This appends or prepends to the last
   kill, if the last command was a kill command.  If FROM is less
   than TO, then the killed text is appended to the most recent kill,
   otherwise it is prepended.  If the last command was not a kill command,
   then a new slot is made for this kill. */
static void
ea_kill_text (from, to)
     int from, to;
{
  register int i, counter, distance;
  int killing_backwards, slot;
  char *killed_text;

  killing_backwards = (from > to);

  /* If killing backwards, reverse the values of FROM and TO. */
  if (killing_backwards)
    {
      int temp = from;
      from = to;
      to = temp;
    }

  /* Remember the text that we are about to delete. */
  distance = to - from;
  killed_text = (char *)xmalloc (1 + distance);
  strncpy (killed_text, &input_line[from], distance);
  killed_text[distance] = '\0';

  /* Actually delete the text from the line. */
  counter = input_line_end - to;

  for (i = from; counter; i++, counter--)
    input_line[i] = input_line[i + distance];

  input_line_end -= distance;

  /* If the last command was a kill, append or prepend the killed text to
     the last command's killed text. */
  if (echo_area_last_command_was_kill)
    {
      char *old, *new;

      slot = kill_ring_loc;
      old = kill_ring[slot];
      new = (char *)xmalloc (1 + strlen (old) + strlen (killed_text));

      if (killing_backwards)
        {
          /* Prepend TEXT to current kill. */
          strcpy (new, killed_text);
          strcat (new, old);
        }
      else
        {
          /* Append TEXT to current kill. */
          strcpy (new, old);
          strcat (new, killed_text);
        }

      free (old);
      free (killed_text);
      kill_ring[slot] = new;
    }
  else
    {
      /* Try to store the kill in a new slot, unless that would cause there
         to be too many remembered kills. */
      slot = kill_ring_index;

      if (slot == max_retained_kills)
        slot = 0;

      if (slot + 1 > kill_ring_slots)
        kill_ring = (char **) xrealloc
          (kill_ring,
           (kill_ring_slots += max_retained_kills) * sizeof (char *));

      if (slot != kill_ring_index)
        free (kill_ring[slot]);
      else
        kill_ring_index++;

      kill_ring[slot] = killed_text;

      kill_ring_loc = slot;
    }

  /* Notice that the last command was a kill. */
  echo_area_last_command_was_kill++;
}

/* **************************************************************** */
/*                                                                  */
/*                      Echo Area Completion                        */
/*                                                                  */
/* **************************************************************** */

/* Pointer to an array of REFERENCE to complete over. */
static REFERENCE **echo_area_completion_items = (REFERENCE **)NULL;

/* Sorted array of REFERENCE * which is the possible completions found in
   the variable echo_area_completion_items.  If there is only one element,
   it is the only possible completion. */
static REFERENCE **completions_found = (REFERENCE **)NULL;
static int completions_found_index = 0;
static int completions_found_slots = 0;

/* The lowest common denominator found while completing. */
static REFERENCE *LCD_completion;

/* Internal functions used by the user calls. */
static void build_completions (), completions_must_be_rebuilt ();

/* Variable which holds the output of completions. */
static NODE *possible_completions_output_node = (NODE *)NULL;

static char *compwin_name = "*Completions*";

/* Return non-zero if WINDOW is a window used for completions output. */
static int
completions_window_p (window)
     WINDOW *window;
{
  int result = 0;

  if (internal_info_node_p (window->node) &&
      (strcmp (window->node->nodename, compwin_name) == 0))
    result = 1;

  return (result);
}

/* Workhorse for completion readers.  If FORCE is non-zero, the user cannot
   exit unless the line read completes, or is empty. */
char *
info_read_completing_internal (window, prompt, completions, force)
     WINDOW *window;
     char *prompt;
     REFERENCE **completions;
     int force;
{
  char *line;

  /* If the echo area is already active, remember the current state. */
  if (echo_area_is_active)
    push_echo_area ();

  echo_area_must_complete_p = force;

  /* Initialize our local variables. */
  initialize_input_line (prompt);

  /* Initialize the echo area for the first (but maybe not the last) time. */
  echo_area_initialize_node ();

  /* Save away the original node of this window, and the window itself,
     so echo area commands can temporarily use this window. */
  remember_calling_window (window);

  /* Save away the list of items to complete over. */
  echo_area_completion_items = completions;
  completions_must_be_rebuilt ();

  active_window = the_echo_area;
  echo_area_is_active++;

  /* Read characters in the echo area. */
  while (1)
    {
      info_read_and_dispatch ();

      line = echo_area_after_read ();

      /* Force the completion to take place if the user hasn't accepted
         a default or aborted, and if FORCE is active. */
      if (force && line && *line && completions)
        {
          register int i;

          build_completions ();

          /* If there is only one completion, then make the line be that
             completion. */
          if (completions_found_index == 1)
            {
              free (line);
              line = xstrdup (completions_found[0]->label);
              break;
            }

          /* If one of the completions matches exactly, then that is okay, so
             return the current line. */
          for (i = 0; i < completions_found_index; i++)
            if (strcasecmp (completions_found[i]->label, line) == 0)
              {
                free (line);
                line = xstrdup (completions_found[i]->label);
                break;
              }

          /* If no match, go back and try again. */
          if (i == completions_found_index)
            {
              inform_in_echo_area (_("Not complete"));
              continue;
            }
        }
      break;
    }
  echo_area_is_active--;

  /* Restore the original active window and show point in it. */
  active_window = calling_window;
  restore_calling_window ();
  display_cursor_at_point (active_window);
  fflush (stdout);

  echo_area_completion_items = (REFERENCE **)NULL;
  completions_must_be_rebuilt ();

  /* If there is a previous loop waiting for us, restore it now. */
  if (echo_area_is_active)
    pop_echo_area ();

  return (line);
}
  
/* Read a line in the echo area with completion over COMPLETIONS. */
char *
info_read_completing_in_echo_area (window, prompt, completions)
     WINDOW *window;
     char *prompt;
     REFERENCE **completions;
{
  return (info_read_completing_internal (window, prompt, completions, 1));
}

/* Read a line in the echo area allowing completion over COMPLETIONS, but
   not requiring it. */
char *
info_read_maybe_completing (window, prompt, completions)
     WINDOW *window;
     char *prompt;
     REFERENCE **completions;
{
  return (info_read_completing_internal (window, prompt, completions, 0));
}

DECLARE_INFO_COMMAND (ea_possible_completions, _("List possible completions"))
{
  if (!echo_area_completion_items)
    {
      ea_insert (window, count, key);
      return;
    }

  build_completions ();

  if (!completions_found_index)
    {
      terminal_ring_bell ();
      inform_in_echo_area (_("No completions"));
    }
  else if ((completions_found_index == 1) && (key != '?'))
    {
      inform_in_echo_area (_("Sole completion"));
    }
  else
    {
      register int i, l;
      int limit, count, max_label = 0;

      initialize_message_buffer ();
      printf_to_message_buffer (completions_found_index == 1
                                ? _("One completion:\n")
                                : _("%d completions:\n"));

      /* Find the maximum length of a label. */
      for (i = 0; i < completions_found_index; i++)
        {
          int len = strlen (completions_found[i]->label);
          if (len > max_label)
            max_label = len;
        }

      max_label += 4;

      /* Find out how many columns we should print in. */
      limit = calling_window->width / max_label;
      if (limit != 1 && (limit * max_label == calling_window->width))
        limit--;

      /* Avoid a possible floating exception.  If max_label > width then
         the limit will be 0 and a divide-by-zero fault will result. */
      if (limit == 0)
        limit = 1;

      /* How many iterations of the printing loop? */
      count = (completions_found_index + (limit - 1)) / limit;

      /* Watch out for special case.  If the number of completions is less
         than LIMIT, then just do the inner printing loop. */
      if (completions_found_index < limit)
        count = 1;

      /* Print the sorted items, up-and-down alphabetically. */
      for (i = 0; i < count; i++)
        {
          register int j;

          for (j = 0, l = i; j < limit; j++)
            {
              if (l >= completions_found_index)
                break;
              else
                {
                  char *label;
                  int printed_length, k;

                  label = completions_found[l]->label;
                  printed_length = strlen (label);
                  printf_to_message_buffer ("%s", label);

                  if (j + 1 < limit)
                    {
                      for (k = 0; k < max_label - printed_length; k++)
                        printf_to_message_buffer (" ");
                    }
                }
              l += count;
            }
          printf_to_message_buffer ("\n");
        }

      /* Make a new node to hold onto possible completions.  Don't destroy
         dangling pointers. */
      {