cmd-edit.cc

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/*

Copyright (C) 1996-2012 John W. Eaton

This file is part of Octave.

Octave 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 3 of the License, or (at your
option) any later version.

Octave 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.

You should have received a copy of the GNU General Public License
along with Octave; see the file COPYING.  If not, see
<http://www.gnu.org/licenses/>.

*/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <cstdlib>
#include <cstring>

#include <string>

#include <sys/types.h>
#include <unistd.h>

#include "quit.h"

#include "cmd-edit.h"
#include "cmd-hist.h"
#include "file-ops.h"
#include "lo-error.h"
#include "lo-utils.h"
#include "oct-env.h"
#include "oct-mutex.h"
#include "oct-time.h"
#include "singleton-cleanup.h"

command_editor *command_editor::instance = 0;

std::set<command_editor::startup_hook_fcn> command_editor::startup_hook_set;

std::set<command_editor::event_hook_fcn> command_editor::event_hook_set;

static octave_mutex event_hook_lock;

#if defined (USE_READLINE)

#include <cstdio>
#include <cstdlib>

#include "oct-rl-edit.h"

class
gnu_readline : public command_editor
{
public:

  typedef command_editor::startup_hook_fcn startup_hook_fcn;

  typedef command_editor::event_hook_fcn event_hook_fcn;

  typedef command_editor::completion_fcn completion_fcn;

  gnu_readline (void);

  ~gnu_readline (void) { }

  void do_set_name (const std::string& n);

  std::string do_readline (const std::string& prompt, bool& eof);

  void do_set_input_stream (FILE *f);

  FILE *do_get_input_stream (void);

  void do_set_output_stream (FILE *f);

  FILE *do_get_output_stream (void);

  int do_terminal_rows (void);

  int do_terminal_cols (void);

  void do_clear_screen (void);

  void do_resize_terminal (void);

  std::string newline_chars (void);

  void do_restore_terminal_state (void);

  void do_blink_matching_paren (bool flag);

  void do_set_basic_word_break_characters (const std::string& s);

  void do_set_completer_word_break_characters (const std::string& s);

  void do_set_basic_quote_characters (const std::string& s);

  void do_set_filename_quote_characters (const std::string& s);

  void do_set_completer_quote_characters (const std::string& s);

  void do_set_completion_append_character (char c);

  void do_set_completion_function (completion_fcn f);

  void do_set_quoting_function (quoting_fcn f);

  void do_set_dequoting_function (dequoting_fcn f);

  void do_set_char_is_quoted_function (char_is_quoted_fcn f);

  void do_set_user_accept_line_function (user_accept_line_fcn f);

  completion_fcn do_get_completion_function (void) const;

  quoting_fcn do_get_quoting_function (void) const;

  dequoting_fcn do_get_dequoting_function (void) const;

  char_is_quoted_fcn do_get_char_is_quoted_function (void) const;

  user_accept_line_fcn do_get_user_accept_line_function (void) const;

  string_vector
  do_generate_filename_completions (const std::string& text);

  std::string do_get_line_buffer (void) const;

  void do_insert_text (const std::string& text);

  void do_newline (void);

  void do_accept_line (void);

  void do_clear_undo_list (void);

  void set_startup_hook (startup_hook_fcn f);

  void restore_startup_hook (void);

  void set_event_hook (event_hook_fcn f);

  void restore_event_hook (void);

  void do_restore_event_hook (void);

  void do_read_init_file (const std::string& file);

  void do_re_read_init_file (void);

  bool do_filename_completion_desired (bool);

  bool do_filename_quoting_desired (bool);

  static int operate_and_get_next (int, int);

  static int history_search_backward (int, int);

  static int history_search_forward (int, int);

private:

  startup_hook_fcn previous_startup_hook;

  event_hook_fcn previous_event_hook;

  completion_fcn completion_function;

  quoting_fcn quoting_function;

  dequoting_fcn dequoting_function;

  char_is_quoted_fcn char_is_quoted_function;

  user_accept_line_fcn user_accept_line_function;

  static char *command_generator (const char *text, int state);

  static char *command_quoter (char *text, int match_type, char *quote_pointer);
  static char *command_dequoter (char *text, int match_type);

  static int command_char_is_quoted (char *text, int index);

  static int command_accept_line (int count, int key);

  static char **command_completer (const char *text, int start, int end);
};

gnu_readline::gnu_readline ()
  : command_editor (), previous_startup_hook (0),
    previous_event_hook (0), completion_function (0),
    quoting_function (0), dequoting_function (0),
    char_is_quoted_function (0), user_accept_line_function (0)
{
  // FIXME -- need interface to rl_add_defun, rl_initialize, and
  // a function to set rl_terminal_name

  std::string term = octave_env::getenv ("TERM");

  octave_rl_set_terminal_name (term.c_str ());

  octave_rl_initialize ();

  do_blink_matching_paren (true);

  // Bind operate-and-get-next.

  octave_rl_add_defun ("operate-and-get-next",
                       gnu_readline::operate_and_get_next,
                       octave_rl_ctrl ('O'));

  // And the history search functions.

  octave_rl_add_defun ("history-search-backward",
                       gnu_readline::history_search_backward,
                       octave_rl_meta ('P'));

  octave_rl_add_defun ("history-search-forward",
                       gnu_readline::history_search_forward,
                       octave_rl_meta ('N'));
}

void
gnu_readline::do_set_name (const std::string& nm)
{
  ::octave_rl_set_name (nm.c_str ());
}

std::string
gnu_readline::do_readline (const std::string& prompt, bool& eof)
{
  std::string retval;

  eof = false;

  char *line = 0;

  const char *p = prompt.c_str ();

  BEGIN_INTERRUPT_IMMEDIATELY_IN_FOREIGN_CODE;

  line = ::octave_rl_readline (p);

  END_INTERRUPT_IMMEDIATELY_IN_FOREIGN_CODE;

  if (line)
    {
      retval = line;

      free (line);
    }
  else
    eof = true;

  return retval;
}

void
gnu_readline::do_set_input_stream (FILE *f)
{
  ::octave_rl_set_input_stream (f);
}

FILE *
gnu_readline::do_get_input_stream (void)
{
  return ::octave_rl_get_input_stream ();
}

void
gnu_readline::do_set_output_stream (FILE *f)
{
  ::octave_rl_set_output_stream (f);
}

FILE *
gnu_readline::do_get_output_stream (void)
{
  return ::octave_rl_get_output_stream ();
}

// GNU readline handles SIGWINCH, so these values have a good chance
// of being correct even if the window changes size (they may be
// wrong if, for example, the luser changes the window size while the
// pager is running, and the signal is handled by the pager instead of
// us.

int
gnu_readline::do_terminal_rows (void)
{
  int sh = ::octave_rl_screen_height ();

  return sh > 0 ? sh : 24;
}

int
gnu_readline::do_terminal_cols (void)
{
  int sw = ::octave_rl_screen_width ();

  return sw > 0 ? sw : 80;
}

void
gnu_readline::do_clear_screen (void)
{
  ::octave_rl_clear_screen ();
}

void
gnu_readline::do_resize_terminal (void)
{
  ::octave_rl_resize_terminal ();
}

std::string
gnu_readline::newline_chars (void)
{
  return "\r\n";
}

void
gnu_readline::do_restore_terminal_state (void)
{
  ::octave_rl_restore_terminal_state ();
}

void
gnu_readline::do_blink_matching_paren (bool flag)
{
  ::octave_rl_enable_paren_matching (flag ? 1 : 0);
}

void
gnu_readline::do_set_basic_word_break_characters (const std::string& s)
{
  ::octave_rl_set_basic_word_break_characters (s.c_str ());
}

void
gnu_readline::do_set_completer_word_break_characters (const std::string& s)
{
  ::octave_rl_set_completer_word_break_characters (s.c_str ());
}

void
gnu_readline::do_set_basic_quote_characters (const std::string& s)
{
  ::octave_rl_set_basic_quote_characters (s.c_str ());
}

void
gnu_readline::do_set_filename_quote_characters (const std::string& s)
{
  ::octave_rl_set_filename_quote_characters (s.c_str ());
}

void
gnu_readline::do_set_completer_quote_characters (const std::string& s)
{
  ::octave_rl_set_completer_quote_characters (s.c_str ());
}

void
gnu_readline::do_set_completion_append_character (char c)
{
  ::octave_rl_set_completion_append_character (c);
}

void
gnu_readline::do_set_completion_function (completion_fcn f)
{
  completion_function = f;

  rl_attempted_completion_fcn_ptr fp
    = f ? gnu_readline::command_completer : 0;

  ::octave_rl_set_completion_function (fp);
}

void
gnu_readline::do_set_quoting_function (quoting_fcn f)
{
  quoting_function = f;

  rl_quoting_fcn_ptr fp
    = f ? gnu_readline::command_quoter : 0;

  ::octave_rl_set_quoting_function (fp);
}

void
gnu_readline::do_set_dequoting_function (dequoting_fcn f)
{
  dequoting_function = f;

  rl_dequoting_fcn_ptr fp
    = f ? gnu_readline::command_dequoter : 0;

  ::octave_rl_set_dequoting_function (fp);
}

void
gnu_readline::do_set_char_is_quoted_function (char_is_quoted_fcn f)
{
  char_is_quoted_function = f;

  rl_char_is_quoted_fcn_ptr fp
    = f ? gnu_readline::command_char_is_quoted : 0;

  ::octave_rl_set_char_is_quoted_function (fp);
}

void
gnu_readline::do_set_user_accept_line_function (user_accept_line_fcn f)
{
  user_accept_line_function = f;

  if (f)
    octave_rl_add_defun ("accept-line", gnu_readline::command_accept_line,
                         ::octave_rl_ctrl ('M'));
  else
    octave_rl_add_defun ("accept-line", ::octave_rl_newline,
                         ::octave_rl_ctrl ('M'));
}

gnu_readline::completion_fcn
gnu_readline::do_get_completion_function (void) const
{
  return completion_function;
}

gnu_readline::quoting_fcn
gnu_readline::do_get_quoting_function (void) const
{
  return quoting_function;
}

gnu_readline::dequoting_fcn
gnu_readline::do_get_dequoting_function (void) const
{
  return dequoting_function;
}

gnu_readline::char_is_quoted_fcn
gnu_readline::do_get_char_is_quoted_function (void) const
{
  return char_is_quoted_function;
}

gnu_readline::user_accept_line_fcn
gnu_readline::do_get_user_accept_line_function (void) const
{
  return user_accept_line_function;
}

string_vector
gnu_readline::do_generate_filename_completions (const std::string& text)
{
  string_vector retval;

  int n = 0;
  int count = 0;

  char *fn = 0;

  while (1)
    {
      fn = ::octave_rl_filename_completion_function (text.c_str (), count);

      if (fn)
        {
          if (count == n)
            {
              // Famous last words:  Most large directories will not
              // have more than a few hundred files, so we should not
              // resize too many times even if the growth is linear...

              n += 100;
              retval.resize (n);
            }

          retval[count++] = fn;

          free (fn);
        }
      else
        break;
    }

  retval.resize (count);

  return retval;
}

std::string
gnu_readline::do_get_line_buffer (void) const
{
  return ::octave_rl_line_buffer ();
}

void
gnu_readline::do_insert_text (const std::string& text)
{
  ::octave_rl_insert_text (text.c_str ());
}

void
gnu_readline::do_newline (void)
{
  ::octave_rl_newline (1, '\n');
}

void
gnu_readline::do_accept_line (void)
{
  command_accept_line (1, '\n');
}

void
gnu_readline::do_clear_undo_list ()
{
  ::octave_rl_clear_undo_list ();
}

void
gnu_readline::set_startup_hook (startup_hook_fcn f)
{
  previous_startup_hook = ::octave_rl_get_startup_hook ();

  if (f != previous_startup_hook)
    ::octave_rl_set_startup_hook (f);
}

void
gnu_readline::restore_startup_hook (void)
{
  ::octave_rl_set_startup_hook (previous_startup_hook);
}

void
gnu_readline::set_event_hook (event_hook_fcn f)
{
  previous_event_hook = octave_rl_get_event_hook ();

  ::octave_rl_set_event_hook (f);
}

void
gnu_readline::restore_event_hook (void)
{
  ::octave_rl_set_event_hook (previous_event_hook);
}

void
gnu_readline::do_read_init_file (const std::string& file)
{
  ::octave_rl_read_init_file (file.c_str ());
}

void
gnu_readline::do_re_read_init_file (void)
{
  ::octave_rl_re_read_init_file ();
}

bool
gnu_readline::do_filename_completion_desired (bool arg)
{
  return ::octave_rl_filename_completion_desired (arg);
}

bool
gnu_readline::do_filename_quoting_desired (bool arg)
{
  return ::octave_rl_filename_quoting_desired (arg);
}

int
gnu_readline::operate_and_get_next (int /* count */, int /* c */)
{
  // Accept the current line.

  command_editor::accept_line ();

  // Find the current line, and find the next line to use.

  int x_where = command_history::where ();

  int x_length = command_history::length ();

  if ((command_history::is_stifled ()
       && (x_length >= command_history::max_input_history ()))
      || (x_where >= x_length - 1))
    command_history::set_mark (x_where);
  else
    command_history::set_mark (x_where + 1);

  command_editor::add_startup_hook (command_history::goto_mark);

  return 0;
}

int
gnu_readline::history_search_backward (int count, int c)
{
  return octave_rl_history_search_backward (count, c);
}

int
gnu_readline::history_search_forward (int count, int c)
{
  return octave_rl_history_search_forward (count, c);
}

char *
gnu_readline::command_generator (const char *text, int state)
{
  char *retval = 0;

  completion_fcn f = command_editor::get_completion_function ();

  std::string tmp = f (text, state);

  size_t len = tmp.length ();

  if (len > 0)
    {
      retval = static_cast<char *> (gnulib::malloc (len+1));

      strcpy (retval, tmp.c_str ());
    }

  return retval;
}

char *
gnu_readline::command_quoter (char *text, int matches, char *qcp)
{
  char *retval = 0;

  quoting_fcn f = command_editor::get_quoting_function ();

  std::string tmp = f (text, matches, *qcp);

  size_t len = tmp.length ();

  if (len > 0)
    {
      retval = static_cast<char *> (gnulib::malloc (len+1));

      strcpy (retval, tmp.c_str ());
    }

  return retval;
}

char *
gnu_readline::command_dequoter (char *text, int quote)
{
  char *retval = 0;

  dequoting_fcn f = command_editor::get_dequoting_function ();

  std::string tmp = f (text, quote);

  size_t len = tmp.length ();

  if (len > 0)
    {
      retval = static_cast<char *> (gnulib::malloc (len+1));

      strcpy (retval, tmp.c_str ());
    }

  return retval;
}

int
gnu_readline::command_char_is_quoted (char *text, int quote)
{
  char_is_quoted_fcn f = command_editor::get_char_is_quoted_function ();

  return f (text, quote);
}

int
gnu_readline::command_accept_line (int count, int key)
{
  user_accept_line_fcn f = command_editor::get_user_accept_line_function ();

  if (f)
    f (::octave_rl_line_buffer ());

  ::octave_rl_redisplay ();

  return ::octave_rl_newline (count, key);
}

char **
gnu_readline::command_completer (const char *text, int, int)
{
  char **matches = 0;
  matches
    = ::octave_rl_completion_matches (text, gnu_readline::command_generator);
  return matches;
}

#endif

class
default_command_editor : public command_editor
{
public:

  default_command_editor (void)
    : command_editor (), input_stream (stdin), output_stream (stdout) { }

  ~default_command_editor (void) { }

  std::string do_readline (const std::string& prompt, bool& eof);

  void do_set_input_stream (FILE *f);

  FILE *do_get_input_stream (void);

  void do_set_output_stream (FILE *f);

  FILE *do_get_output_stream (void);

  string_vector do_generate_filename_completions (const std::string& text);

  std::string do_get_line_buffer (void) const;

  void do_insert_text (const std::string&);

  void do_newline (void);

  void do_accept_line (void);

private:

  FILE *input_stream;

  FILE *output_stream;

  // No copying!

  default_command_editor (const default_command_editor&);

  default_command_editor& operator = (const default_command_editor&);
};

std::string
default_command_editor::do_readline (const std::string& prompt, bool& eof)
{
  gnulib::fputs (prompt.c_str (), output_stream);
  gnulib::fflush (output_stream);

  return octave_fgetl (input_stream, eof);
}

void
default_command_editor::do_set_input_stream (FILE *f)
{
  input_stream = f;
}

FILE *
default_command_editor::do_get_input_stream (void)
{
  return input_stream;
}

void
default_command_editor::do_set_output_stream (FILE *f)
{
  output_stream = f;
}

FILE *
default_command_editor::do_get_output_stream (void)
{
  return output_stream;
}

string_vector
default_command_editor::do_generate_filename_completions (const std::string&)
{
  // FIXME
  return string_vector ();
}

std::string
default_command_editor::do_get_line_buffer (void) const
{
  return "";
}

void
default_command_editor::do_insert_text (const std::string&)
{
  // FIXME
}

void
default_command_editor::do_newline (void)
{
  // FIXME
}

void
default_command_editor::do_accept_line (void)
{
  // FIXME
}

bool
command_editor::instance_ok (void)
{
  bool retval = true;

  if (! instance)
    {
      make_command_editor ();

      if (instance)
        singleton_cleanup_list::add (cleanup_instance);
    }

  if (! instance)
    {
      current_liboctave_error_handler
        ("unable to create command history object!");

      retval = false;
    }

  return retval;
}

void
command_editor::make_command_editor (void)
{
#if defined (USE_READLINE)
  instance = new gnu_readline ();
#else
  instance = new default_command_editor ();
#endif
}

void
command_editor::force_default_editor (void)
{
  delete instance;
  instance = new default_command_editor ();
}

int
command_editor::startup_handler (void)
{
  for (startup_hook_set_iterator p = startup_hook_set.begin ();
       p != startup_hook_set.end (); p++)
    {
      startup_hook_fcn f = *p;

      if (f)
        f ();
    }

  return 0;
}

int
command_editor::event_handler (void)
{
  event_hook_lock.lock ();

  std::set<event_hook_fcn> hook_set (event_hook_set);

  event_hook_lock.unlock ();

  for (event_hook_set_iterator p = hook_set.begin ();
       p != hook_set.end (); p++)
    {
      event_hook_fcn f = *p;

      if (f)
        f ();
    }

  return 0;
}

void
command_editor::set_name (const std::string& n)
{
  if (instance_ok ())
    instance->do_set_name (n);
}

std::string
command_editor::readline (const std::string& prompt)
{
  bool eof;

  return readline (prompt, eof);
}

std::string
command_editor::readline (const std::string& prompt, bool& eof)
{
  return (instance_ok ())
    ? instance->do_readline (prompt, eof) : std::string ();
}

void
command_editor::set_input_stream (FILE *f)
{
  if (instance_ok ())
    instance->do_set_input_stream (f);
}

FILE *
command_editor::get_input_stream (void)
{
  return (instance_ok ())
    ? instance->do_get_input_stream () : 0;
}

void
command_editor::set_output_stream (FILE *f)
{
  if (instance_ok ())
    instance->do_set_output_stream (f);
}

FILE *
command_editor::get_output_stream (void)
{
  return (instance_ok ())
    ? instance->do_get_output_stream () : 0;
}

int
command_editor::terminal_rows (void)
{
  return (instance_ok ())
    ? instance->do_terminal_rows () : -1;
}

int
command_editor::terminal_cols (void)
{
  return (instance_ok ())
    ? instance->do_terminal_cols () : -1;
}

void
command_editor::clear_screen (void)
{
  if (instance_ok ())
    instance->do_clear_screen ();
}

void
command_editor::resize_terminal (void)
{
  if (instance_ok ())
    instance->do_resize_terminal ();
}

std::string
command_editor::decode_prompt_string (const std::string& s)
{
  return (instance_ok ())
    ? instance->do_decode_prompt_string (s) : std::string ();
}

int
command_editor::current_command_number (void)
{
  return (instance_ok ())
    ? instance->command_number : 0;
}

void
command_editor::reset_current_command_number (int n)
{
  if (instance_ok ())
    instance->command_number = n;
}

void
command_editor::increment_current_command_number (void)
{
  if (instance_ok ())
    instance->command_number++;
}

void
command_editor::restore_terminal_state (void)
{
  if (instance_ok ())
    instance->do_restore_terminal_state ();
}

void
command_editor::blink_matching_paren (bool flag)
{
  if (instance_ok ())
    instance->do_blink_matching_paren (flag);
}

void
command_editor::set_basic_word_break_characters (const std::string& s)
{
  if (instance_ok ())
    instance->do_set_basic_word_break_characters (s);
}

void
command_editor::set_completer_word_break_characters (const std::string& s)
{
  if (instance_ok ())
    instance->do_set_completer_word_break_characters (s);
}

void
command_editor::set_basic_quote_characters (const std::string& s)
{
  if (instance_ok ())
    instance->do_set_basic_quote_characters (s);
}

void
command_editor::set_filename_quote_characters (const std::string& s)
{
  if (instance_ok ())
    instance->do_set_filename_quote_characters (s);
}

void
command_editor::set_completer_quote_characters (const std::string& s)
{
  if (instance_ok ())
    instance->do_set_completer_quote_characters (s);
}

void
command_editor::set_completion_append_character (char c)
{
  if (instance_ok ())
    instance->do_set_completion_append_character (c);
}

void
command_editor::set_completion_function (completion_fcn f)
{
  if (instance_ok ())
    instance->do_set_completion_function (f);
}

void
command_editor::set_quoting_function (quoting_fcn f)
{
  if (instance_ok ())
    instance->do_set_quoting_function (f);
}

void
command_editor::set_dequoting_function (dequoting_fcn f)
{
  if (instance_ok ())
    instance->do_set_dequoting_function (f);
}

void
command_editor::set_char_is_quoted_function (char_is_quoted_fcn f)
{
  if (instance_ok ())
    instance->do_set_char_is_quoted_function (f);
}

void
command_editor::set_user_accept_line_function (user_accept_line_fcn f)
{
  if (instance_ok ())
    instance->do_set_user_accept_line_function (f);
}

command_editor::completion_fcn
command_editor::get_completion_function (void)
{
  return (instance_ok ())
    ? instance->do_get_completion_function () : 0;
}

command_editor::quoting_fcn
command_editor::get_quoting_function (void)
{
  return (instance_ok ())
    ? instance->do_get_quoting_function () : 0;
}

command_editor::dequoting_fcn
command_editor::get_dequoting_function (void)
{
  return (instance_ok ())
    ? instance->do_get_dequoting_function () : 0;
}

command_editor::char_is_quoted_fcn
command_editor::get_char_is_quoted_function (void)
{
  return (instance_ok ())
    ? instance->do_get_char_is_quoted_function () : 0;
}

command_editor::user_accept_line_fcn
command_editor::get_user_accept_line_function (void)
{
  return (instance_ok ())
    ? instance->do_get_user_accept_line_function () : 0;
}

string_vector
command_editor::generate_filename_completions (const std::string& text)
{
  return (instance_ok ())
    ? instance->do_generate_filename_completions (text) : string_vector ();
}

std::string
command_editor::get_line_buffer (void)
{
  return (instance_ok ()) ? instance->do_get_line_buffer () : "";
}

void
command_editor::insert_text (const std::string& text)
{
  if (instance_ok ())
    instance->do_insert_text (text);
}

void
command_editor::newline (void)
{
  if (instance_ok ())
    instance->do_newline ();
}

void
command_editor::accept_line (void)
{
  if (instance_ok ())
    instance->do_accept_line ();
}

void
command_editor::clear_undo_list (void)
{
  if (instance_ok ())
    instance->do_clear_undo_list ();
}

void
command_editor::add_startup_hook (startup_hook_fcn f)
{
  if (instance_ok ())
    {
      startup_hook_set.insert (f);

      instance->set_startup_hook (startup_handler);
    }
}

void
command_editor::remove_startup_hook (startup_hook_fcn f)
{
  if (instance_ok ())
    {
      startup_hook_set_iterator p = startup_hook_set.find (f);

      if (p != startup_hook_set.end ())
        startup_hook_set.erase (p);

      if (startup_hook_set.empty ())
        instance->restore_startup_hook ();
    }
}

void
command_editor::add_event_hook (event_hook_fcn f)
{
  octave_autolock guard (event_hook_lock);

  if (instance_ok ())
    {
      event_hook_set.insert (f);

      instance->set_event_hook (event_handler);
    }
}

void
command_editor::remove_event_hook (event_hook_fcn f)
{
  octave_autolock guard (event_hook_lock);

  if (instance_ok ())
    {
      event_hook_set_iterator p = event_hook_set.find (f);

      if (p != event_hook_set.end ())
        event_hook_set.erase (p);

      if (event_hook_set.empty ())
        instance->restore_event_hook ();
    }
}

void
command_editor::run_event_hooks (void)
{
  event_handler ();
}

void
command_editor::read_init_file (const std::string& file_arg)
{
  if (instance_ok ())
    {
      std::string file = file_ops::tilde_expand (file_arg);

      instance->do_read_init_file (file);
    }
}

void
command_editor::re_read_init_file (void)
{
  if (instance_ok ())
    instance->do_re_read_init_file ();
}

bool
command_editor::filename_completion_desired (bool arg)
{
  return (instance_ok ())
    ? instance->do_filename_completion_desired (arg) : false;
}

bool
command_editor::filename_quoting_desired (bool arg)
{
  return (instance_ok ())
    ? instance->do_filename_quoting_desired (arg) : false;
}

// Return a string which will be printed as a prompt.  The string may
// contain special characters which are decoded as follows:
//
//      \a      bell (ascii 07)
//      \d      the date
//      \e      escape (ascii 033)
//      \h      the hostname up to the first '.'
//      \H      the hostname
//      \n      CRLF
//      \r      CR
//      \s      the name of the shell (program)
//      \t      the time
//      \T      the time in 12-hour hh:mm:ss format
//      \@      the time in 12-hour hh:mm am/pm format
//      \A      the time in 24-hour hh:mm format
//      \u      your username
//      \w      the current working directory
//      \W      the last element of PWD
//      \!      the history number of this command
//      \#      the command number of this command
//      \$      a $ or a # if you are root
//      \nnn    character code nnn in octal
//      \\      a backslash
//      \[      begin a sequence of non-printing chars
//      \]      end a sequence of non-printing chars

std::string
command_editor::do_decode_prompt_string (const std::string& s)
{
  std::string result;
  std::string temp;
  size_t i = 0;
  size_t slen = s.length ();
  int c;

  while (i < slen)
    {
      c = s[i];

      i++;

      if (c == '\\')
        {
          c = s[i];

          switch (c)
            {
            case '0':
            case '1':
            case '2':
            case '3':
            case '4':
            case '5':
            case '6':
            case '7':
              // Maybe convert an octal number.
              {
                int n = read_octal (s.substr (i, 3));

                temp = "\\";

                if (n != -1)
                  {
                    i += 3;
                    temp[0] = n;
                  }

                c = 0;
                goto add_string;
              }

            case 'a':
              {
                temp = '\a';

                goto add_string;
              }

            case 'e':
              {
                temp = '\033';

                goto add_string;
              }

            case 'r':
              {
                temp = '\r';

                goto add_string;
              }

            case 'd':
            case 't':
            case 'T':
            case '@':
            case 'A':
              // Make the current time/date into a string.
              {
                octave_localtime now;

                if (c == 'd')
                  temp = now.strftime ("%a %b %d");
                else if (c == 't')
                  temp = now.strftime ("%H:%M:%S");
                else if (c == 'T')
                  temp = now.strftime ("%I:%M:%S");
                else if (c == '@')
                  temp = now.strftime ("%I:%M %p");
                else if (c == 'A')
                  temp = now.strftime ("%H:%M");

                goto add_string;
              }

            case 'n':
              {
                temp = newline_chars ();

                goto add_string;
              }

            case 's':
              {
                temp = octave_env::get_program_name ();
                temp = octave_env::base_pathname (temp);

                goto add_string;
              }

            case 'w':
            case 'W':
              {
                temp = octave_env::get_current_directory ();

                std::string home_dir = octave_env::get_home_directory ();

                if (c == 'W' && (home_dir.empty () || temp != home_dir))
                  {
                    if (temp != "/" && temp != "//")
                      {
                        size_t pos = temp.rfind ('/');

                        if (pos != std::string::npos && pos != 0)
                          temp = temp.substr (pos + 1);
                      }
                  }
                else
                  temp = octave_env::polite_directory_format (temp);

                goto add_string;
              }

            case 'u':
              {
                temp = octave_env::get_user_name ();

                goto add_string;
              }

            case 'H':
              {
                temp = octave_env::get_host_name ();

                goto add_string;
              }

            case 'h':
              {
                temp = octave_env::get_host_name ();

                size_t pos = temp.find ('.');

                if (pos != std::string::npos)
                  temp.resize (pos);

                goto add_string;
              }

            case '#':
              {
                char number_buffer[128];
                sprintf (number_buffer, "%d", command_number);
                temp = number_buffer;

                goto add_string;
              }

            case '!':
              {
                char number_buffer[128];
                int num = command_history::current_number ();
                if (num > 0)
                  sprintf (number_buffer, "%d", num);
                else
                  strcpy (number_buffer, "!");
                temp = number_buffer;

                goto add_string;
              }

            case '$':
              {
#if defined (HAVE_GETEUID)
                temp = (::geteuid () == 0 ? "#" : "$");
#else
                temp = "$";
#endif

                goto add_string;
              }

#if defined (USE_READLINE)
            case '[':
            case ']':
              {
                temp.resize (1);

                temp[0] = ((c == '[')
                           ? ::octave_rl_prompt_start_ignore ()
                           : ::octave_rl_prompt_end_ignore ());

                goto add_string;
              }
#endif

            case '\\':
              {
                temp = "\\";

                goto add_string;
              }

            default:
              {
                temp = "\\ ";
                temp[1] = c;

                goto add_string;
              }

            add_string:
              {
                if (c)
                  i++;

                result.append (temp);

                break;
              }
            }
        }
      else
        result += c;
    }

  return result;
}

// Return the octal number parsed from STRING, or -1 to indicate that
// the string contained a bad number.

int
command_editor::read_octal (const std::string& s)
{
  int result = 0;
  int digits = 0;

  size_t i = 0;
  size_t slen = s.length ();

  while (i < slen && s[i] >= '0' && s[i] < '8')
    {
      digits++;
      result = (result * 8) + s[i] - '0';
      i++;
    }

  if (! digits || result > 0777 || i < slen)
    result = -1;

  return result;
}

void
command_editor::error (int err_num)
{
  current_liboctave_error_handler ("%s", gnulib::strerror (err_num));
}

void
command_editor::error (const std::string& s)
{
  current_liboctave_error_handler ("%s", s.c_str ());
}