display.c

在非GUI环境下

/* display.c -- readline redisplay facility. */

/* Copyright (C) 1987-2004 Free Software Foundation, Inc.

   This file is part of the GNU Readline Library, a library for
   reading lines of text with interactive input and history editing.

   The GNU Readline Library is free software; you can redistribute it
   and/or modify it under the terms of the GNU General Public License
   as published by the Free Software Foundation; either version 2, or
   (at your option) any later version.

   The GNU Readline Library is distributed in the hope that it will be
   useful, but WITHOUT ANY WARRANTY; without even the implied warranty
   of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   The GNU General Public License is often shipped with GNU software, and
   is generally kept in a file called COPYING or LICENSE.  If you do not
   have a copy of the license, write to the Free Software Foundation,
   59 Temple Place, Suite 330, Boston, MA 02111 USA. */
#define READLINE_LIBRARY

#if defined (HAVE_CONFIG_H)
#  include <config.h>
#endif

#include <sys/types.h>

#if defined (HAVE_UNISTD_H)
#  include <unistd.h>
#endif /* HAVE_UNISTD_H */

#include "posixstat.h"

#if defined (HAVE_STDLIB_H)
#  include <stdlib.h>
#else
#  include "ansi_stdlib.h"
#endif /* HAVE_STDLIB_H */

#include <stdio.h>

/* System-specific feature definitions and include files. */
#include "rldefs.h"
#include "rlmbutil.h"

/* Termcap library stuff. */
#include "tcap.h"

/* Some standard library routines. */
#include "readline.h"
#include "history.h"

#include "rlprivate.h"
#include "xmalloc.h"

#if !defined (strchr) && !defined (__STDC__)
extern char *strchr (), *strrchr ();
#endif /* !strchr && !__STDC__ */

#if defined (HACK_TERMCAP_MOTION)
extern char *_rl_term_forward_char;
#endif

static void update_line PARAMS((char *, char *, int, int, int, int));
static void space_to_eol PARAMS((int));
static void delete_chars PARAMS((int));
static void insert_some_chars PARAMS((char *, int, int));
static void cr PARAMS((void));

#if defined (HANDLE_MULTIBYTE)
static int _rl_col_width PARAMS((const char *, int, int));
static int *_rl_wrapped_line;
#else
#  define _rl_col_width(l, s, e)	(((e) <= (s)) ? 0 : (e) - (s))
#endif

static int *inv_lbreaks, *vis_lbreaks;
static int inv_lbsize, vis_lbsize;

/* Heuristic used to decide whether it is faster to move from CUR to NEW
   by backing up or outputting a carriage return and moving forward. */
#define CR_FASTER(new, cur) (((new) + 1) < ((cur) - (new)))

/* **************************************************************** */
/*								    */
/*			Display stuff				    */
/*								    */
/* **************************************************************** */

/* This is the stuff that is hard for me.  I never seem to write good
   display routines in C.  Let's see how I do this time. */

/* (PWP) Well... Good for a simple line updater, but totally ignores
   the problems of input lines longer than the screen width.

   update_line and the code that calls it makes a multiple line,
   automatically wrapping line update.  Careful attention needs
   to be paid to the vertical position variables. */

/* Keep two buffers; one which reflects the current contents of the
   screen, and the other to draw what we think the new contents should
   be.  Then compare the buffers, and make whatever changes to the
   screen itself that we should.  Finally, make the buffer that we
   just drew into be the one which reflects the current contents of the
   screen, and place the cursor where it belongs.

   Commands that want to can fix the display themselves, and then let
   this function know that the display has been fixed by setting the
   RL_DISPLAY_FIXED variable.  This is good for efficiency. */

/* Application-specific redisplay function. */
rl_voidfunc_t *rl_redisplay_function = rl_redisplay;

/* Global variables declared here. */
/* What YOU turn on when you have handled all redisplay yourself. */
int rl_display_fixed = 0;

int _rl_suppress_redisplay = 0;

/* The stuff that gets printed out before the actual text of the line.
   This is usually pointing to rl_prompt. */
char *rl_display_prompt = (char *)NULL;

/* Pseudo-global variables declared here. */
/* The visible cursor position.  If you print some text, adjust this. */
int _rl_last_c_pos = 0;
int _rl_last_v_pos = 0;

/* Number of lines currently on screen minus 1. */
int _rl_vis_botlin = 0;

/* Variables used only in this file. */
/* The last left edge of text that was displayed.  This is used when
   doing horizontal scrolling.  It shifts in thirds of a screenwidth. */
static int last_lmargin;

/* The line display buffers.  One is the line currently displayed on
   the screen.  The other is the line about to be displayed. */
static char *visible_line = (char *)NULL;
static char *invisible_line = (char *)NULL;

/* A buffer for `modeline' messages. */
static char msg_buf[128];

/* Non-zero forces the redisplay even if we thought it was unnecessary. */
static int forced_display;

/* Default and initial buffer size.  Can grow. */
static int line_size = 1024;

/* Variables to keep track of the expanded prompt string, which may
   include invisible characters. */

static char *local_prompt, *local_prompt_prefix;
static int prompt_visible_length, prompt_prefix_length;

/* The number of invisible characters in the line currently being
   displayed on the screen. */
static int visible_wrap_offset;

/* The number of invisible characters in the prompt string.  Static so it
   can be shared between rl_redisplay and update_line */
static int wrap_offset;

/* The index of the last invisible character in the prompt string. */
static int prompt_last_invisible;

/* The length (buffer offset) of the first line of the last (possibly
   multi-line) buffer displayed on the screen. */
static int visible_first_line_len;

/* Number of invisible characters on the first physical line of the prompt.
   Only valid when the number of physical characters in the prompt exceeds
   (or is equal to) _rl_screenwidth. */
static int prompt_invis_chars_first_line;

static int prompt_last_screen_line;

static int prompt_physical_chars;

/* Expand the prompt string S and return the number of visible
   characters in *LP, if LP is not null.  This is currently more-or-less
   a placeholder for expansion.  LIP, if non-null is a place to store the
   index of the last invisible character in the returned string. NIFLP,
   if non-zero, is a place to store the number of invisible characters in
   the first prompt line.  The previous are used as byte counts -- indexes
   into a character buffer. */

/* Current implementation:
	\001 (^A) start non-visible characters
	\002 (^B) end non-visible characters
   all characters except \001 and \002 (following a \001) are copied to
   the returned string; all characters except those between \001 and
   \002 are assumed to be `visible'. */	

static char *
expand_prompt (pmt, lp, lip, niflp, vlp)
     char *pmt;
     int *lp, *lip, *niflp, *vlp;
{
  char *r, *ret, *p;
  int l, rl, last, ignoring, ninvis, invfl, ind, pind, physchars;

  /* Short-circuit if we can. */
  if ((MB_CUR_MAX <= 1 || rl_byte_oriented) && strchr (pmt, RL_PROMPT_START_IGNORE) == 0)
    {
      r = savestring (pmt);
      if (lp)
	*lp = strlen (r);
      if (lip)
	*lip = 0;
      if (niflp)
	*niflp = 0;
      if (vlp)
	*vlp = lp ? *lp : strlen (r);
      return r;
    }

  l = strlen (pmt);
  r = ret = (char *)xmalloc (l + 1);

  invfl = 0;	/* invisible chars in first line of prompt */

  for (rl = ignoring = last = ninvis = physchars = 0, p = pmt; p && *p; p++)
    {
      /* This code strips the invisible character string markers
	 RL_PROMPT_START_IGNORE and RL_PROMPT_END_IGNORE */
      if (*p == RL_PROMPT_START_IGNORE)
	{
	  ignoring++;
	  continue;
	}
      else if (ignoring && *p == RL_PROMPT_END_IGNORE)
	{
	  ignoring = 0;
	  last = r - ret - 1;
	  continue;
	}
      else
	{
#if defined (HANDLE_MULTIBYTE)
	  if (MB_CUR_MAX > 1 && rl_byte_oriented == 0)
	    {
	      pind = p - pmt;
	      ind = _rl_find_next_mbchar (pmt, pind, 1, MB_FIND_NONZERO);
	      l = ind - pind;
	      while (l--)
	        *r++ = *p++;
	      if (!ignoring)
		rl += ind - pind;
	      else
		ninvis += ind - pind;
	      p--;			/* compensate for later increment */
	    }
	  else
#endif
	    {
	      *r++ = *p;
	      if (!ignoring)
		rl++;			/* visible length byte counter */
	      else
		ninvis++;		/* invisible chars byte counter */
	    }

	  if (rl >= _rl_screenwidth)
	    invfl = ninvis;

	  if (ignoring == 0)
	    physchars++;
	}
    }

  if (rl < _rl_screenwidth)
    invfl = ninvis;

  *r = '\0';
  if (lp)
    *lp = rl;
  if (lip)
    *lip = last;
  if (niflp)
    *niflp = invfl;
  if  (vlp)
    *vlp = physchars;
  return ret;
}

/* Just strip out RL_PROMPT_START_IGNORE and RL_PROMPT_END_IGNORE from
   PMT and return the rest of PMT. */
char *
_rl_strip_prompt (pmt)
     char *pmt;
{
  char *ret;

  ret = expand_prompt (pmt, (int *)NULL, (int *)NULL, (int *)NULL, (int *)NULL);
  return ret;
}

/*
 * Expand the prompt string into the various display components, if
 * necessary.
 *
 * local_prompt = expanded last line of string in rl_display_prompt
 *		  (portion after the final newline)
 * local_prompt_prefix = portion before last newline of rl_display_prompt,
 *			 expanded via expand_prompt
 * prompt_visible_length = number of visible characters in local_prompt
 * prompt_prefix_length = number of visible characters in local_prompt_prefix
 *
 * This function is called once per call to readline().  It may also be
 * called arbitrarily to expand the primary prompt.
 *
 * The return value is the number of visible characters on the last line
 * of the (possibly multi-line) prompt.
 */
int
rl_expand_prompt (prompt)
     char *prompt;
{
  char *p, *t;
  int c;

  /* Clear out any saved values. */
  FREE (local_prompt);
  FREE (local_prompt_prefix);

  local_prompt = local_prompt_prefix = (char *)0;
  prompt_last_invisible = prompt_visible_length = 0;

  if (prompt == 0 || *prompt == 0)
    return (0);

  p = strrchr (prompt, '\n');
  if (!p)
    {
      /* The prompt is only one logical line, though it might wrap. */
      local_prompt = expand_prompt (prompt, &prompt_visible_length,
					    &prompt_last_invisible,
					    &prompt_invis_chars_first_line,
					    &prompt_physical_chars);
      local_prompt_prefix = (char *)0;
      return (prompt_visible_length);
    }
  else
    {
      /* The prompt spans multiple lines. */
      t = ++p;
      local_prompt = expand_prompt (p, &prompt_visible_length,
				       &prompt_last_invisible,
				       (int *)NULL,
				       (int *)NULL);
      c = *t; *t = '\0';
      /* The portion of the prompt string up to and including the
	 final newline is now null-terminated. */
      local_prompt_prefix = expand_prompt (prompt, &prompt_prefix_length,
						   (int *)NULL,
						   &prompt_invis_chars_first_line,
						   &prompt_physical_chars);
      *t = c;
      return (prompt_prefix_length);
    }
}

/* Initialize the VISIBLE_LINE and INVISIBLE_LINE arrays, and their associated
   arrays of line break markers.  MINSIZE is the minimum size of VISIBLE_LINE
   and INVISIBLE_LINE; if it is greater than LINE_SIZE, LINE_SIZE is
   increased.  If the lines have already been allocated, this ensures that
   they can hold at least MINSIZE characters. */
static void
init_line_structures (minsize)
      int minsize;
{
  register int n;

  if (invisible_line == 0)	/* initialize it */
    {
      if (line_size < minsize)
	line_size = minsize;
      visible_line = (char *)xmalloc (line_size);
      invisible_line = (char *)xmalloc (line_size);
    }
  else if (line_size < minsize)	/* ensure it can hold MINSIZE chars */
    {
      line_size *= 2;
      if (line_size < minsize)
	line_size = minsize;
      visible_line = (char *)xrealloc (visible_line, line_size);
      invisible_line = (char *)xrealloc (invisible_line, line_size);
    }

  for (n = minsize; n < line_size; n++)
    {
      visible_line[n] = 0;
      invisible_line[n] = 1;
    }

  if (vis_lbreaks == 0)
    {
      /* should be enough. */
      inv_lbsize = vis_lbsize = 256;
      inv_lbreaks = (int *)xmalloc (inv_lbsize * sizeof (int));
      vis_lbreaks = (int *)xmalloc (vis_lbsize * sizeof (int));
#if defined (HANDLE_MULTIBYTE)
      _rl_wrapped_line = (int *)xmalloc (vis_lbsize * sizeof (int));
#endif
      inv_lbreaks[0] = vis_lbreaks[0] = 0;
    }
}
  
/* Basic redisplay algorithm. */
void
rl_redisplay ()
{
  register int in, out, c, linenum, cursor_linenum;
  register char *line;
  int c_pos, inv_botlin, lb_botlin, lb_linenum;
  int newlines, lpos, temp, modmark;
  char *prompt_this_line;
#if defined (HANDLE_MULTIBYTE)
  wchar_t wc;
  size_t wc_bytes;
  int wc_width;
  mbstate_t ps;
  int _rl_wrapped_multicolumn = 0;
#endif

  if (!readline_echoing_p)
    return;

  if (!rl_display_prompt)
    rl_display_prompt = "";

  if (invisible_line == 0)
    {
      init_line_structures (0);
      rl_on_new_line ();
    }

  /* Draw the line into the buffer. */
  c_pos = -1;

  line = invisible_line;
  out = inv_botlin = 0;

  /* Mark the line as modified or not.  We only do this for history
     lines. */
  modmark = 0;
  if (_rl_mark_modified_lines && current_history () && rl_undo_list)
    {
      line[out++] = '*';
      line[out] = '\0';
      modmark = 1;