path: root/TAO/tao/xdr.cpp

// @(#)xdr.cpp	1.3 95/11/07
// Copyright 1995 by Sun Microsystems, Inc.
//
// XDR/TCP ORB Marshaler/unmarshaler
//
// Includes functions to encode 64 and 128 bit quantities, interpretive
// encoder/decoder.
//
// XXX note -- this is incomplete (see xdr.hh) and doesn't do
// exactly what the Prelude protocol does, particularly in the
// area of typecodes.
//
// XXX implement the put/get primitives for 64 and 128 bit data types
//
// XXX strings, principals, typecodes, char arrays, char seqs, and
// same for octets ... all should marshal the bulk characters tightly
// packed, four to a word, else this violates the XDR spec.
//
// XXX optimization 1:  allowed by current XDR spec, when marshaling
// true bulk data could eliminate a buffer copy by writing long
// buffers (bigger than 'remainder of current fragment') in single
// large chunks ... weigh cost of an extra kernel write against data
// copy getting added.  Applies to byte-structured bulk data only,
// not (portably) to arrays of longs etc.
//
// XXX optimization 2:  modifies current XDR spec:  when marshaling
// arrays of "short" data (e.g. unicode strings) pack tightly.
//

#include "tao/orb.h"
#include "tao/debug.h"
#include "tao/principa.h"
#include "tao/xdr.h"

// I/O for 64 bit quantities -- integers, doubles

CORBA_Boolean
XDR_stream::put_longlong (const CORBA_LongLong &)
THROWS_NOTHING
{
  return CORBA_B_FALSE;
}

CORBA_Boolean
XDR_stream::get_longlong (CORBA_LongLong &)
THROWS_NOTHING
{
  return CORBA_B_FALSE;
}

// I/O for 128 bit quantities -- long doubles

CORBA_Boolean
XDR_stream::put_longdouble (const CORBA_LongDouble &)
THROWS_NOTHING
{
  return CORBA_B_FALSE;
}

CORBA_Boolean
XDR_stream::get_longdouble (CORBA_LongDouble &)
THROWS_NOTHING
{
  return CORBA_B_FALSE;
}

// Encode instances of arbitrary data types based only on typecode.
// "data" points to the data type; if it's not a primitve data type,
// the TypeCode interpreter is used to recursively encode its
// components.  "context" is the marshaling stream on which to encode
// the data value.
//
// This is a fairly typical TypeCode interpreter visit() routine; it
// works on a single data value in conjunction with context
// information, and must handle all IDL data types.

CORBA_TypeCode::traverse_status
XDR_stream::encoder (CORBA_TypeCode_ptr  tc,
		     const void		*data,
		     const void		*,
		     void		*context,
		     CORBA_Environment	&env)
  THROWS_NOTHING
{
  CORBA_Boolean	continue_encoding = CORBA_B_TRUE;
  XDR_stream		*stream = (XDR_stream *)context;

  switch (tc->kind_) 
    {
    case tk_null:
    case tk_void:
      // nothing to encode!
      break;
      
    case tk_char:
    case tk_octet:
      continue_encoding = stream->put_char (*(char *)data);
      break;

    case tk_short:
    case tk_ushort:
      continue_encoding = stream->put_short (*(short *)data);
      break;

    case tk_long:
    case tk_ulong:
    case tk_float:
      continue_encoding = stream->put_long (*(CORBA_Long *)data);
      break;

    case tk_double:
    case tk_longlong:
    case tk_ulonglong:
      continue_encoding = stream->put_longlong (*(CORBA_LongLong *)data);
      break;

    case tk_boolean:
      continue_encoding = stream->put_boolean (*(CORBA_Boolean *)data);
      break;

    case tk_enum:
      {
	// NOTE assumption that this is in-range.
	//
	// XXX should check this, it's a hard-to-recover error
	// for the other side
	u_int	value = *(u_int *)data;
	continue_encoding = stream->put_ulong (value);
      }
    break;

    case tk_any:
      {
	CORBA_Any	*any = (CORBA_Any *)data;

	tc = any->type ();
	if (encoder (_tc_CORBA_TypeCode, &tc, 0, context, env)
	    != CORBA_TypeCode::TRAVERSE_CONTINUE)
	  return CORBA_TypeCode::TRAVERSE_STOP;

	data = any->value ();
	return encoder (tc, data, 0, context, env);
      }
    // NOTREACHED

    case tk_TypeCode:
      {
	CORBA_TypeCode_ptr	tc2;

	tc2 = *(CORBA_TypeCode_ptr *)data;

	continue_encoding = stream->put_ulong ((CORBA_ULong) tc2->kind_);
	if (continue_encoding == CORBA_B_FALSE)
	  break;

	switch (tc2->kind_) 
	  {
	    // Most TypeCodes have empty parameter lists
	  default:
	    break;

	    //
	    // A few have "simple" parameter lists
	    //
	  case tk_string:
	  case tk_wstring:
	    continue_encoding = stream->put_ulong (tc2->length_);
	    break;

	    //
	    // Indirected typecodes can't occur at "top level" like
	    // this, only nested inside others!
	    //
	  case ~0:
	    dmsg ("indirected typecode at top level!");
	    continue_encoding = CORBA_B_FALSE;
	    break;

	    //
	    // The rest have "complex" parameter lists that are already
	    // encoded as bulk octets ... put length, then octets
	    //
	  case tk_objref:
	  case tk_struct:
	  case tk_union:
	  case tk_enum:
	  case tk_sequence:
	  case tk_array:
	  case tk_alias:
	  case tk_except:
	    {
	      u_int 	i;

	      continue_encoding = stream->put_ulong (tc2->length_);
	      for (i = 0; i < tc2->length_ && continue_encoding; i++)
		continue_encoding =
		  stream->put_octet (tc2->_buffer [i]);
	    }
	  }
      }
    break;

    case tk_Principal:
      {
	CORBA_Principal_ptr	p = *(CORBA_Principal_ptr*) data;
	u_int			i;

	if (p != 0) 
	  {
	    continue_encoding = stream->put_long (p->id.length);
	    for (i = 0; continue_encoding && i < p->id.length; i++)
	      continue_encoding = stream->put_octet (p->id.buffer [i]);
	  } 
	else
	  continue_encoding = stream->put_long (0);
      }
    break;

    case tk_objref:
      // XXX implement me
      break;

    case tk_sequence:
      {
	// First marshal the sequence length, verifying that it's
	// within the sequence bounds ...
	CORBA_OctetSeq 		*seq = (CORBA_OctetSeq *) data;
	CORBA_ULong		len = seq ? seq->length : 0;

	if (len > 0) 
	  {
	    CORBA_ULong		bounds;

	    bounds = tc->ulong_param (1, env);
	    if (env.exception () != 0)
	      return CORBA_TypeCode::TRAVERSE_STOP;

	    if (bounds != 0 && len > bounds) 
	      {
		env.exception (new CORBA_BAD_PARAM (COMPLETED_MAYBE));
		return CORBA_TypeCode::TRAVERSE_STOP;
	      }
	  }
	continue_encoding = stream->put_ulong (len);

	// Fast exit on error or empty sequence
	if (!continue_encoding || len == 0)
	  break;
      }
    // FALLTHROUGH

    case tk_struct:
    case tk_union:
    case tk_array:
    case tk_alias:
      //
      // Marshal each member in order.
      //
      return tc->traverse (data, 0, encoder, context, env);

    case tk_except:
      // Convert the the "hidden" TypeCode at the beginning of the
      // exception into an on-the-wire ID, then marshal the members in
      // order (traversal skips that hidden typecode, and more).
      //
      // NOTE: This is asymmetric with respect to decoding the
      // exception, since whoever decodes must pull off the ID and map
      // it to the typecode to be used to unmarshal it (search among
      // legal choices).
      {
	CORBA_String	id = tc->id (env);

	if (env.exception () == 0) 
	  {
	    continue_encoding =
	      encoder (_tc_CORBA_String, &id, 0, context, env)
	      == CORBA_TypeCode::TRAVERSE_CONTINUE
	      && tc->traverse (data, 0, encoder, context, env);
	  } 
	else
	  continue_encoding = CORBA_B_FALSE;
      }
    break;

    case tk_string:
      {
	CORBA_String	str = *(CORBA_String *) data;
	CORBA_ULong	len, bounds;

	// Be nice to programmers: treat nulls as empty strings not
	// errors.  (OMG-IDL supports languages that don't use the
	// C/C++ notion of null v. empty strings; nulls aren't part of
	// the OMG-IDL string model.)
	if (str == 0) 
	  {
	    stream->put_ulong (1);
	    stream->put_char (0);
	    break;
	  }

	// Verify string satisfies bounds requirements.  We're not so
	// permissive as to send messages violating the interface spec
	// by having excessively long strings!
	bounds = tc->ulong_param (0, env);
	if (env.exception () != 0)
	  return CORBA_TypeCode::TRAVERSE_STOP;
	len = ACE_OS::strlen ((char *)str);

	if (bounds != 0 && len > bounds) {
	  continue_encoding = CORBA_B_FALSE;
	  break;
	}

	// Encode the string, followed by a NUL character.
	continue_encoding = stream->put_ulong (len + 1);
	while (continue_encoding != CORBA_B_FALSE && *str)
	  continue_encoding = stream->put_char (*str++);
	stream->put_char (0);
      }
    break;

    case tk_wstring:
      {
	wchar_t *str = *(wchar_t **) data;
	CORBA_ULong len, bounds;

	// Be nice to programmers: treat nulls as empty strings not
	// errors.  (OMG-IDL supports languages that don't use the
	// C/C++ notion of null v. empty strings; nulls aren't part of
	// the OMG-IDL string model.)

	if (str == 0) 
	  {
	    stream->put_ulong (1);
	    stream->put_wchar (0);
	    break;
	  }

	// Verify wide string satisfies bounds requirements.  We're
	// not so permissive as to send messages violating the
	// interface spec by having excessively long strings!
	bounds = tc->ulong_param (0, env);
	if (env.exception () != 0)
	  return CORBA_TypeCode::TRAVERSE_STOP;
	len = ACE_OS::strlen (str);
	if (bounds != 0 && len > bounds) 
	  {
	    continue_encoding = CORBA_B_FALSE;
	    break;
	  }

	// Encode the wide string, followed by a NUL character.
	continue_encoding = stream->put_ulong (ACE_OS::strlen (str) + 1);
	while (continue_encoding != CORBA_B_FALSE && *str)
	  continue_encoding = stream->put_wchar (*str++);
	stream->put_wchar (0);
      }
    break;

    case tk_longdouble:
      continue_encoding =
	stream->put_longdouble (*(CORBA_LongDouble *)data);
      break;

    case tk_wchar:
      continue_encoding = stream->put_wchar (*(wchar_t *)data);
      break;
	
      // case ~0:
    default:
      dmsg ("encoder default case ?");
      continue_encoding = CORBA_B_FALSE;
      break;
    }

  if (continue_encoding == CORBA_B_FALSE) 
    {
      env.exception (new CORBA_MARSHAL (COMPLETED_MAYBE));
      dmsg ("marshaling encoder detected error");
      return CORBA_TypeCode::TRAVERSE_STOP;
    }
  return CORBA_TypeCode::TRAVERSE_CONTINUE;
}

// Array of typecodes used to unmarshal ...

extern CORBA_TypeCode_ptr __tc_consts [TC_KIND_COUNT];

CORBA_TypeCode::traverse_status
XDR_stream::decoder (CORBA_TypeCode_ptr  tc,
		     const void		*data,
		     const void		*,
		     void		*context,
		     CORBA_Environment	&env)
  THROWS_NOTHING
{
  CORBA_Boolean	continue_decoding = CORBA_B_TRUE;
  XDR_stream			*stream = (XDR_stream *)context;

  switch (tc->kind_) 
    {
    case tk_null:
    case tk_void:
      // nothing to decode!
      break;
      
    case tk_char:
    case tk_octet:
      continue_decoding = stream->get_char (*(CORBA_Char *)data);
      break;

    case tk_short:
    case tk_ushort:
      continue_decoding = stream->get_short (*(short *)data);
      break;

    case tk_long:
    case tk_ulong:
    case tk_float:
      continue_decoding = stream->get_long (*(CORBA_Long *)data);
      break;

    case tk_longlong:
    case tk_ulonglong:
    case tk_double:
      continue_decoding = stream->get_longlong (*(CORBA_LongLong *)data);
      break;

    case tk_boolean:
      continue_decoding = stream->get_boolean (*(CORBA_Boolean *)data);
      break;

    case tk_enum:
      {
	CORBA_ULong	val;

	// NOTE assumption that this is in-range.
	//
	// XXX should check this, it's rather hard to recover from
	// such errors since they "do not occur" and are essentially
	// never tested for.
	continue_decoding = stream->get_ulong (val);
	*(u_int *)data = (u_int) val;
      }
    break;

    case tk_any:
      {
	CORBA_Any *any = (CORBA_Any *)data;
	CORBA_TypeCode_ptr	tc2;
	void *value;

	if (decoder (_tc_CORBA_TypeCode, &tc2, 0, context, env)
	    != CORBA_TypeCode::TRAVERSE_CONTINUE)
	  return CORBA_TypeCode::TRAVERSE_STOP;

	value = new CORBA_Octet [tc2->size (env)];

	if (decoder (tc2, value, 0, context, env)
	    != CORBA_TypeCode::TRAVERSE_CONTINUE) 
	  {
	    delete value;
	    CORBA_release (tc2);
	    return CORBA_TypeCode::TRAVERSE_STOP;
	  }
	(void) new (any) CORBA_Any (tc2, value, CORBA_B_TRUE);
      }
    break;

    case tk_TypeCode:
      {
	CORBA_ULong		kind;
	CORBA_TypeCode_ptr	*tcp;

	continue_decoding = stream->get_ulong (kind);
	if (continue_decoding == CORBA_B_FALSE)
	  break;
	if (kind >= TC_KIND_COUNT) 
	  {
	    continue_decoding = CORBA_B_FALSE;
	    break;
	  }
	    
	tcp = (CORBA_TypeCode_ptr *)data;

	// Typecodes with empty parameter lists all have preallocated
	// constants.  We use those to reduce memory consumption and
	// heap access ... also, to speed things up!
	if (((*tcp) = __tc_consts [(u_int) kind]) != 0) 
	  {
	    *tcp = __tc_consts [(u_int) kind];
	    break;
	  } 
	else switch (kind) 
	  {
	    // Need special handling for all kinds of typecodes that
	    // have nonempty parameter lists ...
	  default:			// error: missed a case! 
	    env.exception (new CORBA_INTERNAL (COMPLETED_MAYBE));
	    return CORBA_TypeCode::TRAVERSE_STOP;

	    // Some have "simple" parameter lists ... some of these also
	    // have preallocated constants that could be used.
	  case tk_string:
	  case tk_wstring:
	    {
	      CORBA_ULong	bound;

	      continue_decoding = stream->get_ulong (bound);
	      if (continue_decoding) 
		{
		  if (bound == 0) 
		    {
		      if (kind == tk_string)
			*tcp = _tc_CORBA_String;
		      else
			*tcp = _tc_CORBA_WString;
		    } 
		  else 
		    *tcp = new CORBA_TypeCode ((CORBA_TCKind) kind,
					       bound, 0, CORBA_B_TRUE);
		}
	    }
	  break;

	  // Indirected typecodes, illegal at "top level" but we allow
	  // unmarshaling of them here because we use the same code to
	  // read "off the wire" (where they're illegal) and to read
	  // out of an encapsulation stream.  We distinguish the case
	  // where this is legal as described above.

	  case ~0:
	    // XXX implement me
	    break;

	    // The rest have "complex" parameter lists that are
	    // encoded as bulk octets ...
	  case tk_objref:
	  case tk_struct:
	  case tk_union:
	  case tk_enum:
	  case tk_sequence:
	  case tk_array:
	  case tk_alias:
	  case tk_except:
	    {
	      u_int		len, i;
	      CORBA_ULong	length;
	      CORBA_Octet	*buffer;

	      continue_decoding = stream->get_ulong (length);
	      if (!continue_decoding)
		break;

	      // if length > MAXUNSIGNED, error ...
	      len = (u_int) length;

	      buffer = new CORBA_Octet [len];

	      for (i = 0; i < len && continue_decoding; i++)
		continue_decoding = stream->get_octet (buffer [i]);

	      if (!continue_decoding) 
		{
		  delete [] buffer;
		  break;
		}
	      *tcp = new CORBA_TypeCode ((CORBA_TCKind)kind,
					 len, buffer, CORBA_B_TRUE);
	    }
	  }
      }
    break;

    case tk_Principal:
      {
	CORBA_Principal_ptr	*pp = (CORBA_Principal_ptr *)data;
	CORBA_ULong	len;

	continue_decoding = stream->get_ulong (len);
	if (len == 0)
	  *pp = 0;
	else 
	  {
	    *pp = new CORBA_Principal;
	    (*pp)->id.buffer = new CORBA_Octet [(size_t) len];
	    (*pp)->id.maximum = (*pp)->id.length = len;

	    for (u_int i = 0;
		 continue_decoding != CORBA_B_FALSE && i < len;
		 i++)
	      continue_decoding =
		stream->get_octet ((*pp)->id.buffer [i]);
	  }
      }
    break;

    case tk_objref:
      // XXX implement me
      break;

    case tk_sequence:
      {
	// First unmarshal the sequence length ... we trust it to be
	// right here, on the "be gracious in what you accept"
	// principle.  We don't generate illegal sequences
	// (i.e. length > bounds).
	CORBA_OctetSeq 		*seq = (CORBA_OctetSeq *) data;

	continue_decoding = stream->get_ulong (seq->length);
	seq->maximum = seq->length;
	seq->buffer = 0;

	// Fast exit on empty sequences or errors
	if (!continue_decoding || seq->length == 0)
	  break;

	// ... then allocate the memory into which we'll unmarshal
	CORBA_TypeCode_ptr	tc2;
	size_t			size;

	tc2 = tc->typecode_param (0, env);
	if (env.exception ())
	  return CORBA_TypeCode::TRAVERSE_STOP;

	size = tc2->size (env);
	if (env.exception ())
	  return CORBA_TypeCode::TRAVERSE_STOP;

	tc2->Release ();

	seq->buffer = new CORBA_Octet [size * (size_t) seq->maximum];
      }
    // FALLTHROUGH

    case tk_struct:
    case tk_union:
    case tk_array:
    case tk_alias:
      // Unmarshal all the individual elements using the per-member
      // description held in the "parent" TypeCode.
	
      // FALLTHROUGH

    case tk_except:
      // For exceptions, the "hidden" type ID near the front of the
      // on-wire representation was previously unmarshaled and mapped
      // to the "tc" typcode we're using to traverse the memory ...
      // at the same time its vtable, refcount, and other state was
      // established.
      //
      // NOTE:  This is asymmetric with respect to encoding exceptions.
      return tc->traverse (data, 0, decoder, context, env);

    case tk_string:
      {
	CORBA_String	str;
	CORBA_ULong	len = 0;

	// On decode, omit the check against specified string bounds,
	// and cope with illegal "zero length" strings (all lengths on
	// the wire must include a NUL).
	//
	// This is on the principle of being gracious in what we
	// accept; we don't generate messages that fail to comply with
	// protocol specs, but we will accept them when it's clear how
	// to do so.

	continue_decoding = stream->get_ulong (len);
	*((CORBA_String*)data) = str = new CORBA_Char [(size_t) (len)];
	if (len != 0)
	  while (continue_decoding != CORBA_B_FALSE && len-- != 0) 
	    {
	      continue_decoding = stream->get_char (*(CORBA_Char *)str);
	      str++;
	    }
	break;
      }

    case tk_wstring:
      {
	wchar_t		*str;
	CORBA_ULong	len = 0;

	// On decode, omit the check against specified wstring bounds,
	// and cope with illegal "zero length" strings (all lengths on
	// the wire must include a NUL).
	//
	// This is on the principle of being gracious in what we accept;
	// we don't generate messages that fail to comply with protocol
	// specs, but we will accept them when it's clear how to do so.

	continue_decoding = stream->get_ulong (len);
	*((wchar_t **)data) = str = new wchar_t [(size_t) (len)];
	if (len != 0) 
	  while (continue_decoding != CORBA_B_FALSE && len--) 
	    {
	      continue_decoding = stream->get_wchar (*str);
	      str++;
	    }
      }
    break;

    case tk_longdouble:
      continue_decoding =
	stream->get_longdouble (*(CORBA_LongDouble *)data);
      break;

    case tk_wchar:
      continue_decoding = stream->get_wchar (*(wchar_t *)data);
      break;

      // case ~0:
    default:
      continue_decoding = CORBA_B_FALSE;
      dmsg ("decode, default case?");
      break;
    }

  if (continue_decoding == CORBA_B_FALSE) 
    {
      env.exception (new CORBA_MARSHAL (COMPLETED_NO));
      dmsg ("marshaling decoder detected error");
      return CORBA_TypeCode::TRAVERSE_STOP;
    }
  return CORBA_TypeCode::TRAVERSE_CONTINUE;
}

// Write an XDR message fragment out on the stream.

CORBA_Boolean
XDR_stream::flush_frag (CORBA_Boolean /* is_last */)
  THROWS_NOTHING
{
  return CORBA_B_FALSE;

#if	0
  int			status;
  CORBA_ULong		size, header;

  size = index * sizeof (CORBA_ULong);	// byte length of msg
  if (is_last)
    header = 0x80000000 | size;		// indicates last frag
  else
    header = size;
  buffer [0] = htonl (header);

  //
  // XXX for portability, loop until there's no error.  Some
  // platforms/mode don't guarantee full TCP writes even when
  // async (or nonblocking) mode was not set on this socket.
  //
  size += sizeof (CORBA_ULong);
  status = ACE_OS::write (fd, &buffer [0], size);

  index = 0;

  return (status == size);
#endif /* 0 */
}

// Read an XDR message fragment in from the stream.

CORBA_Boolean
XDR_stream::read_frag (void)
  THROWS_NOTHING
{
  // read cookie, split out size and "is last" flag
  // read rest of buffer

  return CORBA_B_FALSE;
}