/*

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Copyright 1992, 1993, 1994 Sun Microsystems, Inc.  Printed in the United
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 */

/*
 * ast_union.cc - Implementation of class AST_Union
 *
 * AST_Union nodes represent IDL union declarations.
 * AST_Union is a subclass of AST_ConcreteType and of UTL_Scope (the
 * union branches are managed in a scope).
 * AST_Union nodes have a discriminator type (a subclass of AST_ConcreteType),
 * a name (an UTL_ScopedName) and a field denoting the discriminator type if
 * it is a primitive type (the value of this field is from the union
 * AST_Expression::ExprType and serves as a cache). This field is used
 * to compute coercions for labels based on the expected discriminator type.
 */

#include	<idl.hh>
#include	<idl_extern.hh>

/*
 * Constructor(s) and destructor
 */
AST_Union::AST_Union()
{
}

AST_Union::AST_Union(AST_ConcreteType *dt, UTL_ScopedName *n, UTL_StrList *p)
	 : AST_Decl(AST_Decl::NT_union, n, p),
	   UTL_Scope(AST_Decl::NT_union)
{
  AST_PredefinedType *pdt;

  if (dt == NULL) {
    pd_disc_type = NULL;
    pd_udisc_type = AST_Expression::EV_none;
    return;
  }
  /*
   * If the discriminator type is a predefined type
   * then install the equivalent coercion target type in
   * the pd_udisc_type field.
   */
  if (dt->node_type() == AST_Decl::NT_pre_defined) {
    pdt = AST_PredefinedType::narrow_from_decl(dt);
    if (pdt == NULL) {
        pd_disc_type = NULL;
        pd_udisc_type = AST_Expression::EV_none;
        return;
    }
    pd_disc_type = dt;
    switch (pdt->pt()) {
    case AST_PredefinedType::PT_long:
      pd_udisc_type = AST_Expression::EV_long;
      break;
    case AST_PredefinedType::PT_ulong:
      pd_udisc_type = AST_Expression::EV_ulong;
      break;
    case AST_PredefinedType::PT_short:
      pd_udisc_type = AST_Expression::EV_short;
      break;
    case AST_PredefinedType::PT_ushort:
      pd_udisc_type = AST_Expression::EV_ushort;
      break;
    case AST_PredefinedType::PT_char:
      pd_udisc_type = AST_Expression::EV_char;
      break;
    case AST_PredefinedType::PT_octet:
      pd_udisc_type = AST_Expression::EV_octet;
      break;
    case AST_PredefinedType::PT_boolean:
      pd_udisc_type = AST_Expression::EV_bool;
      break;
    default:
      pd_udisc_type = AST_Expression::EV_none;
      pd_disc_type = NULL;
      break;
    }
  } else if (dt->node_type() == AST_Decl::NT_enum) {
    pd_udisc_type = AST_Expression::EV_any;
    pd_disc_type = dt;
  } else {
    pd_udisc_type = AST_Expression::EV_none;
    pd_disc_type = NULL;
  }

  if (pd_disc_type == NULL)
    idl_global->err()->error2(UTL_Error::EIDL_DISC_TYPE, this, dt);
}

/*
 * Private operations
 */

/*
 * Look up the default branch in union
 */
AST_UnionBranch *
AST_Union::lookup_default()
{
  UTL_ScopeActiveIterator *i = new UTL_ScopeActiveIterator(this, IK_both);
  AST_UnionBranch	    *b;
  AST_Decl		    *d;

  while (!(i->is_done())) {
    d = i->item();
    if (d->node_type() == AST_Decl::NT_union_branch) {
      b = AST_UnionBranch::narrow_from_decl(d);
      if (b == NULL) {
        i->next();
        continue;
      }
      if (b->label() != NULL &&
	  b->label()->label_kind() == AST_UnionLabel::UL_default) {
	idl_global->err()->error2(UTL_Error::EIDL_MULTIPLE_BRANCH, this, b);
	delete i;
	return b;
      }
    }
    i->next();
  }
  delete i;
  return NULL;
}

/*
 * Look up a branch by label
 */
AST_UnionBranch *
AST_Union::lookup_label(AST_UnionBranch *b)
{
  AST_UnionLabel		*l = b->label();
  UTL_ScopeActiveIterator	*i;
  AST_Decl			*d;
  AST_UnionBranch		*fb;

  if (l->label_val() == NULL)
    return b;
  l->label_val()->set_ev(l->label_val()->coerce(pd_udisc_type));
  if (l->label_val()->ev() == NULL) {
    idl_global->err()->eval_error(l->label_val());
    return b;
  }

  i = new UTL_ScopeActiveIterator(this, IK_decls);

  while (!(i->is_done())) {
    d = i->item();
    if (d->node_type() == AST_Decl::NT_union_branch) {
      fb = AST_UnionBranch::narrow_from_decl(d);
      if (fb == NULL) {
        i->next();
        continue;
      }
      if (fb->label() != NULL &&
	  fb->label()->label_kind() == AST_UnionLabel::UL_label &&
	  fb->label()->label_val()->compare(l->label_val())) {
	idl_global->err()->error2(UTL_Error::EIDL_MULTIPLE_BRANCH, this, b);
	delete i;
	return b;
      }
    }
    i->next();
  }
  delete i;
  return NULL;
}

/*
 * Look up a branch in an enum which is the discriminator type for this
 * union, based on the label value which must be an enumerator in that
 * enum.
 */
AST_UnionBranch *
AST_Union::lookup_enum(AST_UnionBranch *b)
{
  AST_UnionLabel		*l = b->label();
  AST_Expression		*v;
  AST_Enum			*e = AST_Enum::narrow_from_decl(pd_disc_type);
  UTL_ScopeActiveIterator	*i;
  AST_Decl			*d;
  AST_UnionBranch		*fb;

  if (e == NULL) return NULL;
  if (l->label_val() == NULL)
    return b;
  v = l->label_val();
  /*
   * Expecting a symbol label
   */
  if (v->ec() != AST_Expression::EC_symbol) {
    idl_global->err()->enum_val_expected(this, l);
    return b;
  }
  /*
   * See if the symbol defines a constant in the discriminator enum
   */
  d = e->lookup_by_name(v->n(), I_TRUE);
  if (d == NULL || d->defined_in() != e) {
    idl_global->err()->enum_val_lookup_failure(this, e, v->n());
    return b;
  }
  /*
   * OK, now see if this symbol is already used as the label of
   * some other branch
   */
  i = new UTL_ScopeActiveIterator(this, IK_decls);
  while (!(i->is_done())) {
    d = i->item();
    if (d->node_type() == AST_Decl::NT_union_branch) {
      fb = AST_UnionBranch::narrow_from_decl(d);
      if (fb == NULL) {
          i->next();
          continue;
      }
      if (fb->label() != NULL &&
	  fb->label()->label_kind() == AST_UnionLabel::UL_label &&
	  fb->label()->label_val() == l->label_val()) {
	idl_global->err()->error2(UTL_Error::EIDL_MULTIPLE_BRANCH, this, b);
	delete i;
	return b;
      }
    }
    i->next();
  }
  delete i;
  return NULL;
}

/*
 * Look up a branch by value. This is the top level branch label resolution
 * entry point. It dispatches to the right lookup function depending on the
 * union discriminator type.
 */
AST_UnionBranch *
AST_Union::lookup_branch(AST_UnionBranch *branch)
{
  AST_UnionLabel	*l = NULL;

  if (branch != NULL)
    l = branch->label();

  if (l != NULL) {
    if (l->label_kind() == AST_UnionLabel::UL_default)
      return lookup_default();
    if (pd_udisc_type == AST_Expression::EV_any)	
      /* CONVENTION: indicates enum discr */
      return lookup_enum(branch);
    return lookup_label(branch);
  }
  return NULL;
}

/*
 * Public operations
 */

/*
 * Redefinition of inherited virtual operations
 */

/*
 * Add this AST_UnionBranch node (a node representing one branch in a
 * union declaration) to this scope
 */
AST_UnionBranch *AST_Union::fe_add_union_branch(AST_UnionBranch *t)
{
  AST_Decl *d;

  /*
   * If this is a malformed branch, don't do anything with it
   */
  if (t == NULL || t->label() == NULL)
    return NULL;
  /*
   * If branch with that label already exists, complain
   */
  if (lookup_branch(t) != NULL) {
    idl_global->err()->error2(UTL_Error::EIDL_MULTIPLE_BRANCH, this, t);
    return NULL;
  }
  /*
   * If branch with same field name exists, complain
   */
  if ((d = lookup_for_add(t, I_FALSE, I_TRUE)) != NULL) {
    if (!can_be_redefined(d)) {
      idl_global->err()->error3(UTL_Error::EIDL_REDEF, t, this, d);
      return NULL;
    }
    if (referenced(d)) {
      idl_global->err()->error3(UTL_Error::EIDL_DEF_USE, t, this, d);
      return NULL;
    }
    if (t->has_ancestor(d)) {
      idl_global->err()->redefinition_in_scope(t, d);
      return NULL;
    }
  }
  /*
   * Add it to scope
   */
  add_to_scope(t);
  /*
   * Add it to set of locally referenced symbols
   */
  add_to_referenced(t, I_FALSE);

  return t;
}

/*
 * Add this AST_Union (manifest union type) to this scope
 */
AST_Union *AST_Union::fe_add_union(AST_Union *t)
{
  AST_Decl *d;

  /*
   * Already defined and cannot be redefined? Or already used?
   */
  if ((d = lookup_for_add(t, I_FALSE, I_TRUE)) != NULL) {
    if (!can_be_redefined(d)) {
      idl_global->err()->error3(UTL_Error::EIDL_REDEF, t, this, d);
      return NULL;
    }
    if (referenced(d)) {
      idl_global->err()->error3(UTL_Error::EIDL_DEF_USE, t, this, d);
      return NULL;
    }
    if (t->has_ancestor(d)) {
      idl_global->err()->redefinition_in_scope(t, d);
      return NULL;
    }
  }
  /*
   * Add it to local types
   */
  add_to_local_types(t);
  /*
   * Add it to set of locally referenced symbols
   */
  add_to_referenced(t, I_FALSE);

  return t;
}

/*
 * Add this AST_Structure node (manifest struct type) to this scope
 */
AST_Structure *AST_Union::fe_add_structure(AST_Structure *t)
{
  AST_Decl *d;

  /*
   * Already defined and cannot be redefined? Or already used?
   */
  if ((d = lookup_for_add(t, I_FALSE, I_TRUE)) != NULL) {
    if (!can_be_redefined(d)) {
      idl_global->err()->error3(UTL_Error::EIDL_REDEF, t, this, d);
      return NULL;
    }
    if (referenced(d)) {
      idl_global->err()->error3(UTL_Error::EIDL_DEF_USE, t, this, d);
      return NULL;
    }
    if (t->has_ancestor(d)) {
      idl_global->err()->redefinition_in_scope(t, d);
      return NULL;
    }
  }
  /*
   * Add it to local types
   */
  add_to_local_types(t);
  /*
   * Add it to set of locally referenced symbols
   */
  add_to_referenced(t, I_FALSE);

  return t;
}

/*
 * Add this AST_Enum node (manifest enum type) to this scope
 */
AST_Enum *AST_Union::fe_add_enum(AST_Enum *t)
{
  AST_Decl *d;

  /*
   * Already defined and cannot be redefined? Or already used?
   */
  if ((d = lookup_for_add(t, I_FALSE, I_TRUE)) != NULL) {
    if (!can_be_redefined(d)) {
      idl_global->err()->error3(UTL_Error::EIDL_REDEF, t, this, d);
      return NULL;
    }
    if (referenced(d)) {
      idl_global->err()->error3(UTL_Error::EIDL_DEF_USE, t, this, d);
      return NULL;
    }
    if (t->has_ancestor(d)) {
      idl_global->err()->redefinition_in_scope(t, d);
      return NULL;
    }
  }
  /*
   * Add it to local types
   */
  add_to_local_types(t);
  /*
   * Add it to set of locally referenced symbols
   */
  add_to_referenced(t, I_FALSE);

  return t;
}

/*
 * Add this AST_EnumVal node (enumerator declaration) to this scope.
 * This is done to conform to the C++ scoping rules which declare
 * enumerators in the enclosing scope (in addition to declaring them
 * in the enum itself)
 */
AST_EnumVal *AST_Union::fe_add_enum_val(AST_EnumVal *t)
{
  AST_Decl *d;

  /*
   * Already defined and cannot be redefined? Or already used?
   */
  if ((d = lookup_for_add(t, I_FALSE, I_TRUE)) != NULL) {
    if (!can_be_redefined(d)) {
      idl_global->err()->error3(UTL_Error::EIDL_REDEF, t, this, d);
      return NULL;
    }
    if (referenced(d)) {
      idl_global->err()->error3(UTL_Error::EIDL_DEF_USE, t, this, d);
      return NULL;
    }
    if (t->has_ancestor(d)) {
      idl_global->err()->redefinition_in_scope(t, d);
      return NULL;
    }
  }
  /*
   * Add it to scope
   */
  add_to_scope(t);
  /*
   * Add it to set of locally referenced symbols
   */
  add_to_referenced(t, I_FALSE);

  return t;
}

/*
 * Dump this AST_Union node to the ostream o
 */
void
AST_Union::dump(ostream &o)
{
  o << "union ";
  local_name()->dump(o);
  o << " switch (";
  pd_disc_type->local_name()->dump(o);
  o << ") {\n";
  UTL_Scope::dump(o);
  idl_global->indent()->skip_to(o);
  o << "}";
}

/*
 * Data accessors
 */

AST_ConcreteType *
AST_Union::disc_type()
{
  return pd_disc_type;
}

AST_Expression::ExprType
AST_Union::udisc_type()
{
  return pd_udisc_type;
}

// Narrowing
IMPL_NARROW_METHODS2(AST_Union, AST_ConcreteType, UTL_Scope)
IMPL_NARROW_FROM_DECL(AST_Union)
IMPL_NARROW_FROM_SCOPE(AST_Union)
