/*

Copyright (C) 2010 VZLU Prague

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 "defun-dld.h"
#include "ov-base.h"
#include "ov.h"
#include "ov-fcn.h"
#include "ov-usr-fcn.h"
#include "pt-misc.h"
#include "toplev.h"

static void gripe_internal (void)
{
  error ("onCleanup: internal error: cloning nonempty object");
}

class octave_oncleanup : public octave_base_value, octave_auto_shlib
{
public:
  octave_oncleanup (void) : fcn () { }
  octave_oncleanup (const octave_value& fcn);

  octave_base_value *clone (void) const 
    { 
      if (fcn.is_defined ())
        gripe_internal ();
      return empty_clone (); 
    }

  octave_base_value *empty_clone (void) const { return new octave_oncleanup (); }

  ~octave_oncleanup (void);

  bool is_defined (void) const { return true; }

  bool is_object (void) const { return true; } // do we want this?

  octave_map map_value (void) const
    { return scalar_map_value (); }

  octave_scalar_map scalar_map_value (void) const;

  dim_vector dims (void) const { static dim_vector dv (1, 1); return dv; }

  bool save_ascii (std::ostream& os);

  bool load_ascii (std::istream& is);

  bool save_binary (std::ostream& os, bool& save_as_floats);

  bool load_binary (std::istream& is, bool swap, 
                    oct_mach_info::float_format fmt);

#if defined (HAVE_HDF5)
  bool save_hdf5 (hid_t loc_id, const char *name, bool save_as_floats);

  bool load_hdf5 (hid_t loc_id, const char *name);
#endif

  void print (std::ostream& os, bool pr_as_read_syntax = false) const;

  void print_raw (std::ostream& os, bool pr_as_read_syntax = false) const;

private:

  DECLARE_OV_TYPEID_FUNCTIONS_AND_DATA

protected:

    octave_value fcn;

};

DEFINE_OV_TYPEID_FUNCTIONS_AND_DATA (octave_oncleanup, "onCleanup", "onCleanup");

octave_oncleanup::octave_oncleanup (const octave_value& f)
  : fcn (f)
{
  if (f.is_function_handle ())
    {
      octave_function *fptr = f.function_value (true);
      if (fptr)
        {
          octave_user_function *uptr = dynamic_cast<octave_user_function *> (fptr);
          if (uptr != 0)
            {
              tree_parameter_list *pl = uptr->parameter_list ();
              if (pl != 0 && pl->length () > 0)
                warning ("onCleanup: cleanup action takes parameters");
            }
        }
      else
        error ("onCleanup: no default dispatch for function handle");
    }
  else
    {
      fcn = octave_value ();
      error ("onCleanup: argument must be a function handle");
    }
}

octave_oncleanup::~octave_oncleanup (void)
{
  if (fcn.is_undefined ())
    return;

  unwind_protect frame;

  // Clear interrupts.
  frame.protect_var (octave_interrupt_state);
  octave_interrupt_state = 0;

  // Disallow quit().
  frame.protect_var (quit_allowed);
  quit_allowed = false;
  
  // Clear errors.
  frame.protect_var (error_state);
  error_state = 0;

  try
    {
      // Run the actual code.
      fcn.do_multi_index_op (0, octave_value_list ());
    }
  catch (octave_interrupt_exception)
    {
      // Swallow the interrupt.
      warning ("onCleanup: interrupt occured in cleanup action");
    }
  catch (std::bad_alloc)
    {
      // Swallow the exception.
      warning ("onCleanup: out of memory occured in cleanup action");
    }
  catch (...) // Yes, the black hole. We're in a d-tor.
    {
      // This shouldn't happen, in theory.
      error ("onCleanup: internal error: unhandled exception in cleanup action");
    }

  // We don't want to ignore errors that occur in the cleanup code, so
  // if an error is encountered there, leave error_state alone.
  // Otherwise, set it back to what it was before.
  if (error_state)
    {
      frame.discard_top ();
      octave_call_stack::backtrace_error_message ();
    }
}

octave_scalar_map 
octave_oncleanup::scalar_map_value (void) const
{
  octave_scalar_map retval;
  retval.setfield ("task", fcn);
  return retval;
}

static void 
warn_save_load (void)
{
  warning ("onCleanup: load and save not supported");
}

bool 
octave_oncleanup::save_ascii (std::ostream& /* os */)
{
  warn_save_load ();
  return true;
}

bool 
octave_oncleanup::load_ascii (std::istream& /* is */)
{
  warn_save_load ();
  return true;
}

bool 
octave_oncleanup::save_binary (std::ostream& /* os */, bool& /* save_as_floats */)
{
  warn_save_load ();
  return true;
}


bool 
octave_oncleanup::load_binary (std::istream& /* is */, bool /* swap */, 
                               oct_mach_info::float_format /* fmt */)
{
  warn_save_load ();
  return true;
}

#if defined (HAVE_HDF5)
bool 
octave_oncleanup::save_hdf5 (hid_t /* loc_id */, const char * /* name */, 
                             bool /* save_as_floats */)
{
  warn_save_load ();
  return true;
}

bool 
octave_oncleanup::load_hdf5 (hid_t /* loc_id */, const char * /* name */)
{
  warn_save_load ();
  return true;
}
#endif

void 
octave_oncleanup::print (std::ostream& os, bool pr_as_read_syntax) const
{
  print_raw (os, pr_as_read_syntax);
  newline (os);
}

void 
octave_oncleanup::print_raw (std::ostream& os, bool pr_as_read_syntax) const
{
  os << "onCleanup (";
  if (fcn.is_defined ())
    fcn.print_raw (os, pr_as_read_syntax);
  os << ")";
}

DEFUN_DLD (onCleanup, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Loadable Function} {@var{c} =} onCleanup (@var{action})\n\
Creates a special object that executes a given function upon destruction.\n\
If the object is copied to multiple variables (or cell or struct array elements)\n\
or returned from a function, @var{action} will be executed after clearing the last\n\
copy of the object.  Note that if multiple local onCleanup variables are created, the\n\
order in which they are called is unspecified.\n\
@seealso{unwind_protect}\n\
@end deftypefn")
{
  octave_value retval;

  if (args.length () == 1)
    {
      if (octave_oncleanup::static_type_id () < 0)
        octave_oncleanup::register_type ();

      retval = new octave_oncleanup (args(0));
    }
  else
    print_usage ();

  return retval;
}