guile/libguile/goops.c

/* Copyright 1998-2004,2008-2015,2017-2018
     Free Software Foundation, Inc.

   This file is part of Guile.

   Guile is free software: you can redistribute it and/or modify it
   under the terms of the GNU Lesser General Public License as published
   by the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   Guile 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 Lesser General Public
   License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with Guile.  If not, see
   <https://www.gnu.org/licenses/>.  */


/* This software is a derivative work of other copyrighted softwares; the
 * copyright notices of these softwares are placed in the file COPYRIGHTS
 *
 * This file is based upon stklos.c from the STk distribution by
 * Erick Gallesio <eg@unice.fr>.
 */

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

#include "async.h"
#include "boolean.h"
#include "chars.h"
#include "dynwind.h"
#include "eval.h"
#include "extensions.h"
#include "foreign.h"
#include "gsubr.h"
#include "hashtab.h"
#include "keywords.h"
#include "macros.h"
#include "modules.h"
#include "numbers.h"
#include "pairs.h"
#include "ports-internal.h"
#include "ports.h"
#include "procprop.h"
#include "programs.h"
#include "smob.h"
#include "strings.h"
#include "strports.h"
#include "symbols.h"
#include "variable.h"
#include "vectors.h"
#include "weak-table.h"

#include "goops.h"


/* Objects have identity, so references to classes and instances are by
   value, not by reference.  Redefinition of a class or modification of
   an instance causes in-place update; you can think of GOOPS as
   building in its own indirection, and for that reason referring to
   GOOPS values by variable reference is unnecessary.

   References to ordinary procedures is by reference (by variable),
   though, as in the rest of Guile.  */

SCM_KEYWORD (k_name, "name");
SCM_KEYWORD (k_setter, "setter");
SCM_SYMBOL (sym_redefined, "redefined");
SCM_GLOBAL_SYMBOL (scm_sym_args, "args");

static int goops_loaded_p = 0;

static SCM var_make_standard_class = SCM_BOOL_F;
static SCM var_class_of_obsolete_indirect_instance = SCM_BOOL_F;
static SCM var_make = SCM_BOOL_F;
static SCM var_inherit_applicable = SCM_BOOL_F;
static SCM var_class_name = SCM_BOOL_F;
static SCM var_class_direct_supers = SCM_BOOL_F;
static SCM var_class_direct_slots = SCM_BOOL_F;
static SCM var_class_direct_subclasses = SCM_BOOL_F;
static SCM var_class_direct_methods = SCM_BOOL_F;
static SCM var_class_precedence_list = SCM_BOOL_F;
static SCM var_class_slots = SCM_BOOL_F;

static SCM var_generic_function_methods = SCM_BOOL_F;
static SCM var_method_generic_function = SCM_BOOL_F;
static SCM var_method_specializers = SCM_BOOL_F;
static SCM var_method_procedure = SCM_BOOL_F;

static SCM var_slot_ref = SCM_BOOL_F;
static SCM var_slot_set_x = SCM_BOOL_F;
static SCM var_slot_bound_p = SCM_BOOL_F;
static SCM var_slot_exists_p = SCM_BOOL_F;

/* These variables are filled in by the object system when loaded. */
static SCM class_boolean, class_char, class_pair;
static SCM class_procedure, class_string, class_symbol;
static SCM class_primitive_generic;
static SCM class_vector, class_null;
static SCM class_integer, class_real, class_complex, class_fraction;
static SCM class_unknown;
static SCM class_top, class_class;
static SCM class_applicable;
static SCM class_applicable_struct, class_applicable_struct_with_setter;
static SCM class_generic, class_generic_with_setter;
static SCM class_accessor;
static SCM class_extended_generic, class_extended_generic_with_setter;
static SCM class_extended_accessor;
static SCM class_method;
static SCM class_accessor_method;
static SCM class_procedure_class;
static SCM class_applicable_struct_class;
static SCM class_applicable_struct_with_setter_class;
static SCM class_number, class_list;
static SCM class_keyword;
static SCM class_syntax;
static SCM class_atomic_box;
static SCM class_port, class_input_output_port;
static SCM class_input_port, class_output_port;

static SCM class_foreign;
static SCM class_hashtable;
static SCM class_fluid;
static SCM class_dynamic_state;
static SCM class_frame;
static SCM class_vm_cont;
static SCM class_bytevector;
static SCM class_uvec;
static SCM class_array;
static SCM class_bitvector;

static SCM vtable_class_map = SCM_BOOL_F;

/* SMOB classes.  */
SCM scm_i_smob_class[SCM_I_MAX_SMOB_TYPE_COUNT];

SCM scm_module_goops;

static SCM scm_sys_make_vtable_vtable (SCM layout);
static SCM scm_sys_init_layout_x (SCM class, SCM layout);
static SCM scm_sys_clear_fields_x (SCM obj, SCM unbound);
static SCM scm_sys_goops_early_init (void);
static SCM scm_sys_goops_loaded (void);




SCM_DEFINE (scm_sys_make_vtable_vtable, "%make-vtable-vtable", 1, 0, 0,
            (SCM layout),
	    "")
#define FUNC_NAME s_scm_sys_make_vtable_vtable
{
  return scm_i_make_vtable_vtable (layout);
}
#undef FUNC_NAME

SCM
scm_make_standard_class (SCM meta, SCM name, SCM dsupers, SCM dslots)
{
  return scm_call_4 (scm_variable_ref (var_make_standard_class),
                     meta, name, dsupers, dslots);
}

SCM_DEFINE (scm_sys_init_layout_x, "%init-layout!", 2, 0, 0,
	    (SCM class, SCM layout),
	    "")
#define FUNC_NAME s_scm_sys_init_layout_x
{
  SCM_VALIDATE_INSTANCE (1, class);
  SCM_ASSERT (!scm_is_symbol (SCM_VTABLE_LAYOUT (class)), class, 1, FUNC_NAME);
  SCM_VALIDATE_STRING (2, layout);

  SCM_SET_VTABLE_LAYOUT (class, scm_make_struct_layout (layout));
  scm_i_struct_inherit_vtable_magic (scm_class_of (class), class);
  SCM_SET_CLASS_FLAGS (class, SCM_VTABLE_FLAG_GOOPS_CLASS);

  return SCM_UNSPECIFIED;
}
#undef FUNC_NAME




static SCM
get_indirect_slots (SCM x)
{
  /* Precondition: X is an indirect instance.  The indirect slots are in
     the last field.  */
  scm_t_bits nfields =
    SCM_STRUCT_DATA_REF (SCM_STRUCT_VTABLE (x), scm_vtable_index_size);

  return SCM_STRUCT_SLOT_REF (x, nfields - 1);
}

/* This function is used for efficient type dispatch.  */
SCM_DEFINE (scm_class_of, "class-of", 1, 0, 0,
	    (SCM x),
	    "Return the class of @var{x}.")
#define FUNC_NAME s_scm_class_of
{
  switch (SCM_ITAG3 (x))
    {
    case scm_tc3_int_1:
    case scm_tc3_int_2:
      return class_integer;

    case scm_tc3_imm24:
      if (SCM_CHARP (x))
	return class_char;
      else if (scm_is_bool (x))
        return class_boolean;
      else if (scm_is_null (x))
        return class_null;
      else
        return class_unknown;

    case scm_tc3_cons:
      switch (SCM_TYP7 (x))
	{
	case scm_tcs_cons_nimcar:
	  return class_pair;
	case scm_tc7_symbol:
	  return class_symbol;
	case scm_tc7_vector:
	case scm_tc7_wvect:
	  return class_vector;
	case scm_tc7_pointer:
	  return class_foreign;
	case scm_tc7_hashtable:
	  return class_hashtable;
	case scm_tc7_fluid:
	  return class_fluid;
	case scm_tc7_dynamic_state:
	  return class_dynamic_state;
        case scm_tc7_frame:
	  return class_frame;
        case scm_tc7_keyword:
	  return class_keyword;
        case scm_tc7_syntax:
	  return class_syntax;
        case scm_tc7_atomic_box:
	  return class_atomic_box;
        case scm_tc7_vm_cont:
	  return class_vm_cont;
	case scm_tc7_bytevector:
          if (SCM_BYTEVECTOR_ELEMENT_TYPE (x) == SCM_ARRAY_ELEMENT_TYPE_VU8)
            return class_bytevector;
          else
            return class_uvec;
	case scm_tc7_array:
          return class_array;
	case scm_tc7_bitvector:
          return class_bitvector;
	case scm_tc7_string:
	  return class_string;
        case scm_tc7_number:
          switch SCM_TYP16 (x) {
          case scm_tc16_big:
            return class_integer;
          case scm_tc16_real:
            return class_real;
          case scm_tc16_complex:
            return class_complex;
	  case scm_tc16_fraction:
	    return class_fraction;
          }
	case scm_tc7_program:
	  if (SCM_PROGRAM_IS_PRIMITIVE_GENERIC (x)
              && SCM_UNPACK (*SCM_SUBR_GENERIC (x)))
	    return class_primitive_generic;
	  else
	    return class_procedure;

	case scm_tc7_smob:
	  {
	    scm_t_bits type = SCM_TYP16 (x);
	    if (type != scm_tc16_port_with_ps)
	      return scm_i_smob_class[SCM_TC2SMOBNUM (type)];
	    x = SCM_PORT_WITH_PS_PORT (x);
	    /* fall through to ports */
	  }
	case scm_tc7_port:
          {
            scm_t_port_type *ptob = SCM_PORT_TYPE (x);
            if (SCM_INPUT_PORT_P (x))
              {
                if (SCM_OUTPUT_PORT_P (x))
                  return ptob->input_output_class;
                return ptob->input_class;
              }
            return ptob->output_class;
          }
	case scm_tcs_struct:
          {
            SCM vtable = SCM_STRUCT_VTABLE (x);
            scm_t_bits flags = SCM_VTABLE_FLAGS (vtable);
            scm_t_bits direct = SCM_VTABLE_FLAG_GOOPS_CLASS;
            scm_t_bits indirect = direct | SCM_VTABLE_FLAG_GOOPS_INDIRECT;
            scm_t_bits mask = indirect;
            if ((flags & mask) == direct)
              /* A direct GOOPS object.  */
              return vtable;
            else if ((flags & mask) == indirect)
              /* An indirect GOOPS object.  If the vtable of the slots
                 object is flagged to indicate that there's a new class
                 definition available, migrate the instance before
                 returning the class.  */
              {
                SCM slots = get_indirect_slots (x);
                scm_t_bits slot_flags = SCM_OBJ_CLASS_FLAGS (slots);
                if (slot_flags & SCM_VTABLE_FLAG_GOOPS_NEEDS_MIGRATION)
                  return scm_call_1
                    (scm_variable_ref (var_class_of_obsolete_indirect_instance),
                     x);
                else
                  return vtable;
              }
            else
              /* A non-GOOPS struct.  */
              return scm_i_define_class_for_vtable (vtable);
          }
	default:
	  if (scm_is_pair (x))
	    return class_pair;
	  else
	    return class_unknown;
	}

    case scm_tc3_struct:
    case scm_tc3_tc7_1:
    case scm_tc3_tc7_2:
      /* case scm_tc3_unused: */
      /* Never reached */
      break;
    }
  return class_unknown;
}
#undef FUNC_NAME




SCM_DEFINE (scm_instance_p, "instance?", 1, 0, 0,
	    (SCM obj),
	    "Return @code{#t} if @var{obj} is an instance.")
#define FUNC_NAME s_scm_instance_p
{
  return scm_from_bool (SCM_INSTANCEP (obj));
}
#undef FUNC_NAME

int
scm_is_generic (SCM x)
{
  return SCM_INSTANCEP (x) && SCM_SUBCLASSP (scm_class_of (x), class_generic);
}

int
scm_is_method (SCM x)
{
  return SCM_INSTANCEP (x) && SCM_SUBCLASSP (scm_class_of (x), class_method);
}




SCM
scm_class_name (SCM obj)
{
  return scm_call_1 (scm_variable_ref (var_class_name), obj);
}

SCM
scm_class_direct_supers (SCM obj)
{
  return scm_call_1 (scm_variable_ref (var_class_direct_supers), obj);
}

SCM
scm_class_direct_slots (SCM obj)
{
  return scm_call_1 (scm_variable_ref (var_class_direct_slots), obj);
}

SCM
scm_class_direct_subclasses (SCM obj)
{
  return scm_call_1 (scm_variable_ref (var_class_direct_subclasses), obj);
}

SCM
scm_class_direct_methods (SCM obj)
{
  return scm_call_1 (scm_variable_ref (var_class_direct_methods), obj);
}

SCM
scm_class_precedence_list (SCM obj)
{
  return scm_call_1 (scm_variable_ref (var_class_precedence_list), obj);
}

SCM
scm_class_slots (SCM obj)
{
  return scm_call_1 (scm_variable_ref (var_class_slots), obj);
}




SCM_DEFINE (scm_generic_function_name, "generic-function-name", 1, 0, 0,
            (SCM obj),
	    "Return the name of the generic function @var{obj}.")
#define FUNC_NAME s_scm_generic_function_name
{
  SCM_VALIDATE_GENERIC (1, obj);
  return scm_procedure_property (obj, scm_sym_name);
}
#undef FUNC_NAME

SCM
scm_generic_function_methods (SCM obj)
{
  return scm_call_1 (scm_variable_ref (var_generic_function_methods), obj);
}

SCM
scm_method_generic_function (SCM obj)
{
  return scm_call_1 (scm_variable_ref (var_method_generic_function), obj);
}

SCM
scm_method_specializers (SCM obj)
{
  return scm_call_1 (scm_variable_ref (var_method_specializers), obj);
}

SCM
scm_method_procedure (SCM obj)
{
  return scm_call_1 (scm_variable_ref (var_method_procedure), obj);
}




SCM
scm_slot_ref (SCM obj, SCM slot_name)
{
  return scm_call_2 (scm_variable_ref (var_slot_ref), obj, slot_name);
}

SCM
scm_slot_set_x (SCM obj, SCM slot_name, SCM value)
{
  return scm_call_3 (scm_variable_ref (var_slot_set_x), obj, slot_name, value);
}

SCM
scm_slot_bound_p (SCM obj, SCM slot_name)
{
  return scm_call_2 (scm_variable_ref (var_slot_bound_p), obj, slot_name);
}

SCM
scm_slot_exists_p (SCM obj, SCM slot_name)
{
  return scm_call_2 (scm_variable_ref (var_slot_exists_p), obj, slot_name);
}




SCM_DEFINE (scm_sys_clear_fields_x, "%clear-fields!", 2, 0, 0,
	    (SCM obj, SCM unbound),
            "")
#define FUNC_NAME s_scm_sys_clear_fields_x
{
  scm_t_signed_bits n, i;

  SCM_VALIDATE_STRUCT (1, obj);
  n = SCM_STRUCT_SIZE (obj);

  /* Set all SCM-holding slots to the GOOPS unbound value.  */
  for (i = 0; i < n; i++)
    if (!SCM_STRUCT_FIELD_IS_UNBOXED (obj, i))
      SCM_STRUCT_SLOT_SET (obj, i, unbound);

  return SCM_UNSPECIFIED;
}
#undef FUNC_NAME




static scm_i_pthread_mutex_t goops_lock = SCM_I_PTHREAD_MUTEX_INITIALIZER;

SCM_DEFINE (scm_sys_modify_instance, "%modify-instance", 2, 0, 0,
	    (SCM old, SCM new),
	    "Used by change-class to modify objects in place.")
#define FUNC_NAME s_scm_sys_modify_instance
{
  scm_t_bits i, old_nfields, new_nfields;

  SCM_VALIDATE_INSTANCE (1, old);
  SCM_VALIDATE_INSTANCE (2, new);

  old_nfields = SCM_STRUCT_DATA_REF (SCM_STRUCT_VTABLE (old),
                                     scm_vtable_index_size);
  new_nfields = SCM_STRUCT_DATA_REF (SCM_STRUCT_VTABLE (new),
                                     scm_vtable_index_size);
  SCM_ASSERT (old_nfields == new_nfields, new, SCM_ARG2, FUNC_NAME);

  /* Exchange the data contained in old and new. We exchange rather than
     scratch the old value with new to be correct with GC.  See "Class
     redefinition protocol" in goops.scm.  */
  scm_i_pthread_mutex_lock (&goops_lock);
  /* Swap vtables.  */
  {
    scm_t_bits tmp = SCM_CELL_WORD_0 (old);
    SCM_SET_CELL_WORD_0 (old, SCM_CELL_WORD_0 (new));
    SCM_SET_CELL_WORD_0 (new, tmp);
  }
  /* Swap data.  */
  for (i = 0; i < old_nfields; i++)
    {
      scm_t_bits tmp = SCM_STRUCT_DATA_REF (old, i);
      SCM_STRUCT_DATA_SET (old, i, SCM_STRUCT_DATA_REF (new, i));
      SCM_STRUCT_DATA_SET (new, i, tmp);
    }
  scm_i_pthread_mutex_unlock (&goops_lock);
  return SCM_UNSPECIFIED;
}
#undef FUNC_NAME



/* Primitive generics: primitives that can dispatch to generics if their
   arguments fail to apply.  */

SCM_DEFINE (scm_generic_capability_p, "generic-capability?", 1, 0, 0,
	    (SCM proc),
	    "")
#define FUNC_NAME s_scm_generic_capability_p
{
  SCM_ASSERT (scm_is_true (scm_procedure_p (proc)),
	      proc, SCM_ARG1, FUNC_NAME);
  return (SCM_PRIMITIVE_GENERIC_P (proc) ? SCM_BOOL_T : SCM_BOOL_F);
}
#undef FUNC_NAME

SCM_DEFINE (scm_enable_primitive_generic_x, "enable-primitive-generic!", 0, 0, 1,
	    (SCM subrs),
	    "")
#define FUNC_NAME s_scm_enable_primitive_generic_x
{
  SCM_VALIDATE_REST_ARGUMENT (subrs);
  while (!scm_is_null (subrs))
    {
      SCM subr = SCM_CAR (subrs);
      SCM_ASSERT (SCM_PRIMITIVE_GENERIC_P (subr), subr, SCM_ARGn, FUNC_NAME);
      SCM_SET_SUBR_GENERIC (subr,
                            scm_make (scm_list_3 (class_generic,
                                                  k_name,
                                                  SCM_SUBR_NAME (subr))));
      subrs = SCM_CDR (subrs);
    }
  return SCM_UNSPECIFIED;
}
#undef FUNC_NAME

SCM_DEFINE (scm_set_primitive_generic_x, "set-primitive-generic!", 2, 0, 0,
	    (SCM subr, SCM generic),
	    "")
#define FUNC_NAME s_scm_set_primitive_generic_x
{
  SCM_ASSERT (SCM_PRIMITIVE_GENERIC_P (subr), subr, SCM_ARG1, FUNC_NAME);
  SCM_ASSERT (SCM_GENERICP (generic), generic, SCM_ARG2, FUNC_NAME);
  SCM_SET_SUBR_GENERIC (subr, generic);
  return SCM_UNSPECIFIED;
}
#undef FUNC_NAME

SCM_DEFINE (scm_primitive_generic_generic, "primitive-generic-generic", 1, 0, 0,
	    (SCM subr),
	    "")
#define FUNC_NAME s_scm_primitive_generic_generic
{
  if (SCM_PRIMITIVE_GENERIC_P (subr))
    {
      if (!SCM_UNPACK (*SCM_SUBR_GENERIC (subr)))
	scm_enable_primitive_generic_x (scm_list_1 (subr));
      return *SCM_SUBR_GENERIC (subr);
    }
  SCM_WRONG_TYPE_ARG (SCM_ARG1, subr);
}
#undef FUNC_NAME

SCM
scm_wta_dispatch_0 (SCM gf, const char *subr)
{
  if (!SCM_UNPACK (gf))
    scm_error_num_args_subr (subr);

  return scm_call_0 (gf);
}

SCM
scm_wta_dispatch_1 (SCM gf, SCM a1, int pos, const char *subr)
{
  if (!SCM_UNPACK (gf))
    scm_wrong_type_arg (subr, pos, a1);

  return scm_call_1 (gf, a1);
}

SCM
scm_wta_dispatch_2 (SCM gf, SCM a1, SCM a2, int pos, const char *subr)
{
  if (!SCM_UNPACK (gf))
    scm_wrong_type_arg (subr, pos, (pos == SCM_ARG1) ? a1 : a2);

  return scm_call_2 (gf, a1, a2);
}

SCM
scm_wta_dispatch_n (SCM gf, SCM args, int pos, const char *subr)
{
  if (!SCM_UNPACK (gf))
    scm_wrong_type_arg (subr, pos, scm_list_ref (args, scm_from_int (pos)));

  return scm_apply_0 (gf, args);
}




SCM
scm_make (SCM args)
{
  return scm_apply_0 (scm_variable_ref (var_make), args);
}




/* SMOB, struct, and port classes.  */

static SCM
make_class_name (const char *prefix, const char *type_name, const char *suffix)
{
  if (!type_name)
    type_name = "";
  return scm_string_to_symbol (scm_string_append
                               (scm_list_3 (scm_from_utf8_string (prefix),
                                            scm_from_utf8_string (type_name),
                                            scm_from_utf8_string (suffix))));
}

SCM
scm_make_extended_class (char const *type_name, int applicablep)
{
  SCM name, meta, supers;

  name = make_class_name ("<", type_name, ">");
  meta = class_class;

  if (applicablep)
    supers = scm_list_1 (class_applicable);
  else
    supers = scm_list_1 (class_top);

  return scm_make_standard_class (meta, name, supers, SCM_EOL);
}

void
scm_i_inherit_applicable (SCM c)
{
  scm_call_1 (scm_variable_ref (var_inherit_applicable), c);
}

static void
create_smob_classes (void)
{
  long i;

  for (i = 0; i < SCM_I_MAX_SMOB_TYPE_COUNT; ++i)
    scm_i_smob_class[i] = SCM_BOOL_F;

  for (i = 0; i < scm_numsmob; ++i)
    if (scm_is_false (scm_i_smob_class[i]))
      scm_i_smob_class[i] = scm_make_extended_class (SCM_SMOBNAME (i),
                                                     scm_smobs[i].apply != 0);
}

struct pre_goops_port_type
{
  scm_t_port_type *ptob;
  struct pre_goops_port_type *prev;
};
struct pre_goops_port_type *pre_goops_port_types;

static void
make_port_classes (scm_t_port_type *ptob)
{
  SCM name, meta, super, supers;

  meta = class_class;

  name = make_class_name ("<", ptob->name, "-port>");
  supers = scm_list_1 (class_port);
  super = scm_make_standard_class (meta, name, supers, SCM_EOL);

  name = make_class_name ("<", ptob->name, "-input-port>");
  supers = scm_list_2 (super, class_input_port);
  ptob->input_class = scm_make_standard_class (meta, name, supers, SCM_EOL);

  name = make_class_name ("<", ptob->name, "-output-port>");
  supers = scm_list_2 (super, class_output_port);
  ptob->output_class = scm_make_standard_class (meta, name, supers, SCM_EOL);

  name = make_class_name ("<", ptob->name, "-input-output-port>");
  supers = scm_list_2 (super, class_input_output_port);
  ptob->input_output_class =
    scm_make_standard_class (meta, name, supers, SCM_EOL);
}

void
scm_make_port_classes (scm_t_port_type *ptob)
{
  ptob->input_class = SCM_BOOL_F;
  ptob->output_class = SCM_BOOL_F;
  ptob->input_output_class = SCM_BOOL_F;

  if (!goops_loaded_p)
    {
      /* Not really a pair.  */
      struct pre_goops_port_type *link;
      link = scm_gc_typed_calloc (struct pre_goops_port_type);
      link->ptob = ptob;
      link->prev = pre_goops_port_types;
      pre_goops_port_types = link;
      return;
    }

  make_port_classes (ptob);
}

static void
create_port_classes (void)
{
  while (pre_goops_port_types)
    {
      make_port_classes (pre_goops_port_types->ptob);
      pre_goops_port_types = pre_goops_port_types->prev;
    }
}

SCM
scm_i_define_class_for_vtable (SCM vtable)
{
  SCM class;

  scm_i_pthread_mutex_lock (&scm_i_misc_mutex);
  if (scm_is_false (vtable_class_map))
    vtable_class_map = scm_c_make_weak_table (0, SCM_WEAK_TABLE_KIND_KEY);
  scm_i_pthread_mutex_unlock (&scm_i_misc_mutex);

  if (scm_is_false (scm_struct_vtable_p (vtable)))
    abort ();

  class = scm_weak_table_refq (vtable_class_map, vtable, SCM_BOOL_F);

  if (scm_is_false (class))
    {
      if (SCM_UNPACK (class_class))
        {
          SCM name, meta, supers;

          name = SCM_VTABLE_NAME (vtable);
          if (scm_is_symbol (name))
            name = scm_string_to_symbol
              (scm_string_append
               (scm_list_3 (scm_from_latin1_string ("<"),
                            scm_symbol_to_string (name),
                            scm_from_latin1_string (">"))));
          else
            name = scm_from_latin1_symbol ("<>");

          if (SCM_STRUCT_VTABLE_FLAG_IS_SET (vtable, SCM_VTABLE_FLAG_SETTER))
            {
              meta = class_applicable_struct_with_setter_class;
              supers = scm_list_1 (class_applicable_struct_with_setter);
            }
          else if (SCM_STRUCT_VTABLE_FLAG_IS_SET (vtable,
                                                  SCM_VTABLE_FLAG_APPLICABLE))
            {
              meta = class_applicable_struct_class;
              supers = scm_list_1 (class_applicable_struct);
            }
          else
            {
              meta = class_class;
              supers = scm_list_1 (class_top);
            }

          class = scm_make_standard_class (meta, name, supers, SCM_EOL);
        }
      else
        /* `create_struct_classes' will fill this in later.  */
        class = SCM_BOOL_F;

      /* Don't worry about races.  This only happens when creating a
         vtable, which happens by definition in one thread.  */
      scm_weak_table_putq_x (vtable_class_map, vtable, class);
    }

  return class;
}

static SCM
make_struct_class (void *closure SCM_UNUSED,
		   SCM vtable, SCM data, SCM prev SCM_UNUSED)
{
  if (scm_is_false (data))
    scm_i_define_class_for_vtable (vtable);
  return SCM_UNSPECIFIED;
}

static void
create_struct_classes (void)
{
  /* FIXME: take the vtable_class_map while initializing goops?  */
  scm_internal_hash_fold (make_struct_class, 0, SCM_BOOL_F,
                          vtable_class_map);
}




void
scm_load_goops ()
{
  if (!goops_loaded_p)
    scm_c_resolve_module ("oop goops");
}

SCM
scm_ensure_accessor (SCM name)
{
  SCM var, gf;

  var = scm_module_variable (scm_current_module (), name);
  if (SCM_VARIABLEP (var) && !SCM_UNBNDP (SCM_VARIABLE_REF (var)))
    gf = SCM_VARIABLE_REF (var);
  else
    gf = SCM_BOOL_F;

  if (!SCM_IS_A_P (gf, class_accessor))
    {
      gf = scm_make (scm_list_3 (class_generic, k_name, name));
      gf = scm_make (scm_list_5 (class_accessor,
				 k_name, name, k_setter, gf));
    }

  return gf;
}




SCM_DEFINE (scm_sys_goops_early_init, "%goops-early-init", 0, 0, 0,
	    (),
	    "")
#define FUNC_NAME s_scm_sys_goops_early_init
{
  var_make_standard_class = scm_c_lookup ("make-standard-class");
  var_make = scm_c_lookup ("make");
  var_inherit_applicable = scm_c_lookup ("inherit-applicable!");

  /* For SCM_SUBCLASSP.  */
  var_class_precedence_list = scm_c_lookup ("class-precedence-list");

  var_slot_ref = scm_c_lookup ("slot-ref");
  var_slot_set_x = scm_c_lookup ("slot-set!");
  var_slot_bound_p = scm_c_lookup ("slot-bound?");
  var_slot_exists_p = scm_c_lookup ("slot-exists?");

  class_class = scm_variable_ref (scm_c_lookup ("<class>"));
  class_top = scm_variable_ref (scm_c_lookup ("<top>"));

  /* Applicables */
  class_procedure_class = scm_variable_ref (scm_c_lookup ("<procedure-class>"));
  class_applicable_struct_class = scm_variable_ref (scm_c_lookup ("<applicable-struct-class>"));
  class_applicable_struct_with_setter_class =
    scm_variable_ref (scm_c_lookup ("<applicable-struct-with-setter-class>"));

  class_method = scm_variable_ref (scm_c_lookup ("<method>"));
  class_accessor_method = scm_variable_ref (scm_c_lookup ("<accessor-method>"));
  class_applicable = scm_variable_ref (scm_c_lookup ("<applicable>"));
  class_applicable_struct = scm_variable_ref (scm_c_lookup ("<applicable-struct>"));
  class_applicable_struct_with_setter = scm_variable_ref (scm_c_lookup ("<applicable-struct-with-setter>"));
  class_generic = scm_variable_ref (scm_c_lookup ("<generic>"));
  class_extended_generic = scm_variable_ref (scm_c_lookup ("<extended-generic>"));
  class_generic_with_setter = scm_variable_ref (scm_c_lookup ("<generic-with-setter>"));
  class_accessor = scm_variable_ref (scm_c_lookup ("<accessor>"));
  class_extended_generic_with_setter = scm_variable_ref (scm_c_lookup ("<extended-generic-with-setter>"));
  class_extended_accessor = scm_variable_ref (scm_c_lookup ("<extended-accessor>"));

  /* Primitive types classes */
  class_boolean = scm_variable_ref (scm_c_lookup ("<boolean>"));
  class_char = scm_variable_ref (scm_c_lookup ("<char>"));
  class_list = scm_variable_ref (scm_c_lookup ("<list>"));
  class_pair = scm_variable_ref (scm_c_lookup ("<pair>"));
  class_null = scm_variable_ref (scm_c_lookup ("<null>"));
  class_string = scm_variable_ref (scm_c_lookup ("<string>"));
  class_symbol = scm_variable_ref (scm_c_lookup ("<symbol>"));
  class_vector = scm_variable_ref (scm_c_lookup ("<vector>"));
  class_foreign = scm_variable_ref (scm_c_lookup ("<foreign>"));
  class_hashtable = scm_variable_ref (scm_c_lookup ("<hashtable>"));
  class_fluid = scm_variable_ref (scm_c_lookup ("<fluid>"));
  class_dynamic_state = scm_variable_ref (scm_c_lookup ("<dynamic-state>"));
  class_frame = scm_variable_ref (scm_c_lookup ("<frame>"));
  class_keyword = scm_variable_ref (scm_c_lookup ("<keyword>"));
  class_syntax = scm_variable_ref (scm_c_lookup ("<syntax>"));
  class_atomic_box = scm_variable_ref (scm_c_lookup ("<atomic-box>"));
  class_vm_cont = scm_variable_ref (scm_c_lookup ("<vm-continuation>"));
  class_bytevector = scm_variable_ref (scm_c_lookup ("<bytevector>"));
  class_uvec = scm_variable_ref (scm_c_lookup ("<uvec>"));
  class_array = scm_variable_ref (scm_c_lookup ("<array>"));
  class_bitvector = scm_variable_ref (scm_c_lookup ("<bitvector>"));
  class_number = scm_variable_ref (scm_c_lookup ("<number>"));
  class_complex = scm_variable_ref (scm_c_lookup ("<complex>"));
  class_real = scm_variable_ref (scm_c_lookup ("<real>"));
  class_integer = scm_variable_ref (scm_c_lookup ("<integer>"));
  class_fraction = scm_variable_ref (scm_c_lookup ("<fraction>"));
  class_unknown = scm_variable_ref (scm_c_lookup ("<unknown>"));
  class_procedure = scm_variable_ref (scm_c_lookup ("<procedure>"));
  class_primitive_generic = scm_variable_ref (scm_c_lookup ("<primitive-generic>"));
  class_port = scm_variable_ref (scm_c_lookup ("<port>"));
  class_input_port = scm_variable_ref (scm_c_lookup ("<input-port>"));
  class_output_port = scm_variable_ref (scm_c_lookup ("<output-port>"));
  class_input_output_port = scm_variable_ref (scm_c_lookup ("<input-output-port>"));

  create_smob_classes ();
  create_struct_classes ();
  create_port_classes ();

  return SCM_UNSPECIFIED;
}
#undef FUNC_NAME

SCM_DEFINE (scm_sys_goops_loaded, "%goops-loaded", 0, 0, 0,
	    (),
	    "Announce that GOOPS is loaded and perform initialization\n"
	    "on the C level which depends on the loaded GOOPS modules.")
#define FUNC_NAME s_scm_sys_goops_loaded
{
  goops_loaded_p = 1;
  var_class_name = scm_c_lookup ("class-name");
  var_class_direct_supers = scm_c_lookup ("class-direct-supers");
  var_class_direct_slots = scm_c_lookup ("class-direct-slots");
  var_class_direct_subclasses = scm_c_lookup ("class-direct-subclasses");
  var_class_direct_methods = scm_c_lookup ("class-direct-methods");
  var_class_slots = scm_c_lookup ("class-slots");

  var_generic_function_methods = scm_c_lookup ("generic-function-methods");
  var_method_generic_function = scm_c_lookup ("method-generic-function");
  var_method_specializers = scm_c_lookup ("method-specializers");
  var_method_procedure = scm_c_lookup ("method-procedure");

  var_class_of_obsolete_indirect_instance =
    scm_c_lookup ("class-of-obsolete-indirect-instance");

  return SCM_UNSPECIFIED;
}
#undef FUNC_NAME

static void
scm_init_goops_builtins (void *unused)
{
  scm_module_goops = scm_current_module ();

#include "goops.x"

  scm_c_define ("vtable-flag-vtable",
                scm_from_int (SCM_VTABLE_FLAG_VTABLE));
  scm_c_define ("vtable-flag-applicable-vtable",
                scm_from_int (SCM_VTABLE_FLAG_APPLICABLE_VTABLE));
  scm_c_define ("vtable-flag-setter-vtable",
                scm_from_int (SCM_VTABLE_FLAG_SETTER_VTABLE));
  scm_c_define ("vtable-flag-validated",
                scm_from_int (SCM_VTABLE_FLAG_VALIDATED));
  scm_c_define ("vtable-flag-goops-class",
                scm_from_int (SCM_VTABLE_FLAG_GOOPS_CLASS));
  scm_c_define ("vtable-flag-goops-slot",
                scm_from_int (SCM_VTABLE_FLAG_GOOPS_SLOT));
  scm_c_define ("vtable-flag-goops-static-slot-allocation",
                scm_from_int (SCM_VTABLE_FLAG_GOOPS_STATIC_SLOT_ALLOCATION));
  scm_c_define ("vtable-flag-goops-indirect",
                scm_from_int (SCM_VTABLE_FLAG_GOOPS_INDIRECT));
  scm_c_define ("vtable-flag-goops-needs-migration",
                scm_from_int (SCM_VTABLE_FLAG_GOOPS_NEEDS_MIGRATION));
}

void
scm_init_goops ()
{
  scm_c_register_extension ("libguile-" SCM_EFFECTIVE_VERSION,
                            "scm_init_goops_builtins", scm_init_goops_builtins,
                            NULL);
}