readline/callback.c

/* callback.c -- functions to use readline as an X `callback' mechanism. */

/* Copyright (C) 1987-2005 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 "rlconf.h"

#if defined (READLINE_CALLBACKS)

#include <sys/types.h>

#ifdef HAVE_STDLIB_H
#  include <stdlib.h>
#else
#  include "ansi_stdlib.h"
#endif

#include <stdio.h>

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

/* Private data for callback registration functions.  See comments in
   rl_callback_read_char for more details. */
_rl_callback_func_t *_rl_callback_func = 0;
_rl_callback_generic_arg *_rl_callback_data = 0;

/* **************************************************************** */
/*								    */
/*			Callback Readline Functions		 */
/*								    */
/* **************************************************************** */

/* Allow using readline in situations where a program may have multiple
   things to handle at once, and dispatches them via select().  Call
   rl_callback_handler_install() with the prompt and a function to call
   whenever a complete line of input is ready.  The user must then
   call rl_callback_read_char() every time some input is available, and 
   rl_callback_read_char() will call the user's function with the complete
   text read in at each end of line.  The terminal is kept prepped and
   signals handled all the time, except during calls to the user's function. */

rl_vcpfunc_t *rl_linefunc;		/* user callback function */
static int in_handler;		/* terminal_prepped and signals set? */

/* Make sure the terminal is set up, initialize readline, and prompt. */
static void
_rl_callback_newline ()
{
  rl_initialize ();

  if (in_handler == 0)
    {
      in_handler = 1;

      if (rl_prep_term_function)
	(*rl_prep_term_function) (_rl_meta_flag);

#if defined (HANDLE_SIGNALS)
      rl_set_signals ();
#endif
    }

  readline_internal_setup ();
}

/* Install a readline handler, set up the terminal, and issue the prompt. */
void
rl_callback_handler_install (prompt, linefunc)
     const char *prompt;
     rl_vcpfunc_t *linefunc;
{
  rl_set_prompt (prompt);
  RL_SETSTATE (RL_STATE_CALLBACK);
  rl_linefunc = linefunc;
  _rl_callback_newline ();
}

/* Read one character, and dispatch to the handler if it ends the line. */
void
rl_callback_read_char ()
{
  char *line;
  int eof, jcode;
  static procenv_t olevel;

  if (rl_linefunc == NULL)
    {
      fprintf (stderr, "readline: readline_callback_read_char() called with no handler!\r\n");
      abort ();
    }

  memcpy ((void *)olevel, (void *)readline_top_level, sizeof (procenv_t));
  jcode = setjmp (readline_top_level);
  if (jcode)
    {
      (*rl_redisplay_function) ();
      _rl_want_redisplay = 0;
      memcpy ((void *)readline_top_level, (void *)olevel, sizeof (procenv_t));
      return;
    }

  if  (RL_ISSTATE (RL_STATE_ISEARCH))
    {
      eof = _rl_isearch_callback (_rl_iscxt);
      if (eof == 0 && (RL_ISSTATE (RL_STATE_ISEARCH) == 0) && RL_ISSTATE (RL_STATE_INPUTPENDING))
	rl_callback_read_char ();

      return;
    }
  else if  (RL_ISSTATE (RL_STATE_NSEARCH))
    {
      eof = _rl_nsearch_callback (_rl_nscxt);
      return;
    }
  else if (RL_ISSTATE (RL_STATE_NUMERICARG))
    {
      eof = _rl_arg_callback (_rl_argcxt);
      if (eof == 0 && (RL_ISSTATE (RL_STATE_NUMERICARG) == 0) && RL_ISSTATE (RL_STATE_INPUTPENDING))
	rl_callback_read_char ();
      /* XXX - this should handle _rl_last_command_was_kill better */
      else if (RL_ISSTATE (RL_STATE_NUMERICARG) == 0)
	_rl_internal_char_cleanup ();

      return;
    }
  else if (RL_ISSTATE (RL_STATE_MULTIKEY))
    {
      eof = _rl_dispatch_callback (_rl_kscxt);	/* For now */
      while ((eof == -1 || eof == -2) && RL_ISSTATE (RL_STATE_MULTIKEY) && _rl_kscxt && (_rl_kscxt->flags & KSEQ_DISPATCHED))
	eof = _rl_dispatch_callback (_rl_kscxt);
      if (RL_ISSTATE (RL_STATE_MULTIKEY) == 0)
	{
	  _rl_internal_char_cleanup ();
	  _rl_want_redisplay = 1;
	}
    }
  else if (_rl_callback_func)
    {
      /* This allows functions that simply need to read an additional character
	 (like quoted-insert) to register a function to be called when input is
	 available.  _rl_callback_data is simply a pointer to a struct that has
	 the argument count originally passed to the registering function and
	 space for any additional parameters.  */
      eof = (*_rl_callback_func) (_rl_callback_data);
      /* If the function `deregisters' itself, make sure the data is cleaned
	 up. */
      if (_rl_callback_func == 0)
	{
	  if (_rl_callback_data) 	
	    {
	      _rl_callback_data_dispose (_rl_callback_data);
	      _rl_callback_data = 0;
	    }
	  _rl_internal_char_cleanup ();
	}
    }
  else
    eof = readline_internal_char ();

  if (rl_done == 0 && _rl_want_redisplay)
    {
      (*rl_redisplay_function) ();
      _rl_want_redisplay = 0;
    }

  /* We loop in case some function has pushed input back with rl_execute_next. */
  for (;;)
    {
      if (rl_done)
	{
	  line = readline_internal_teardown (eof);

	  if (rl_deprep_term_function)
	    (*rl_deprep_term_function) ();
#if defined (HANDLE_SIGNALS)
	  rl_clear_signals ();
#endif
	  in_handler = 0;
	  (*rl_linefunc) (line);

	  /* If the user did not clear out the line, do it for him. */
	  if (rl_line_buffer[0])
	    _rl_init_line_state ();

	  /* Redisplay the prompt if readline_handler_{install,remove}
	     not called. */
	  if (in_handler == 0 && rl_linefunc)
	    _rl_callback_newline ();
	}
      if (rl_pending_input || _rl_pushed_input_available () || RL_ISSTATE (RL_STATE_MACROINPUT))
	eof = readline_internal_char ();
      else
	break;
    }
}

/* Remove the handler, and make sure the terminal is in its normal state. */
void
rl_callback_handler_remove ()
{
  rl_linefunc = NULL;
  RL_UNSETSTATE (RL_STATE_CALLBACK);
  if (in_handler)
    {
      in_handler = 0;
      if (rl_deprep_term_function)
	(*rl_deprep_term_function) ();
#if defined (HANDLE_SIGNALS)
      rl_clear_signals ();
#endif
    }
}

_rl_callback_generic_arg *
_rl_callback_data_alloc (count)
     int count;
{
  _rl_callback_generic_arg *arg;

  arg = (_rl_callback_generic_arg *)xmalloc (sizeof (_rl_callback_generic_arg));
  arg->count = count;

  arg->i1 = arg->i2 = 0;

  return arg;
}

void _rl_callback_data_dispose (arg)
     _rl_callback_generic_arg *arg;
{
  if (arg)
    free (arg);
}

#endif