TAO: TAO_On_Demand_Fragmentation_Strategy class Reference

Constructor & Destructor Documentation

TAO_On_Demand_Fragmentation_Strategy::TAO_On_Demand_Fragmentation_Strategy	(	TAO_Transport *	transport,
		ACE_CDR::ULong	max_message_size
	)

Constructor.

TAO_On_Demand_Fragmentation_Strategy::TAO_On_Demand_Fragmentation_Strategy ( TAO_On_Demand_Fragmentation_Strategy const & ) [private]

Member Function Documentation

int TAO_On_Demand_Fragmentation_Strategy::fragment	(	TAO_OutputCDR &	cdr,
		ACE_CDR::ULong	pending_alignment,
		ACE_CDR::ULong	pending_length
	)	`[virtual]`

Fragment the (potentially partially) encoded GIOP message.

Fragmentation the contents of the CDR output stream cdr into smaller chunks of data of size that fits within the configured ORB fragmentation threshold, and send each fragment "over the wire."

Note:: Fragmentation will only occur if the CDR stream length will surpass the configured fragmentation threshold when marshaling the pending set of data.

Parameters:

cdr	Output CDR stream.
pending_alignment	Size of alignment boundary for next data to be marshaled (e.g. 4 for a CORBA::ULong).
pending_length	Size of next data to be marshaled (e.g. 2 for a CORBA::UShort).

Returns:: Zero on success.

Implements TAO_GIOP_Fragmentation_Strategy.

Definition at line 25 of file On_Demand_Fragmentation_Strategy.cpp.

References ACE_align_binary, ACE_DEBUG, ACE_OutputCDR::align_write_ptr(), TAO_Pluggable_Messaging::generate_fragment_header(), ACE_OutputCDR::get_version(), LM_DEBUG, max_message_size_, TAO_OutputCDR::message_semantics(), TAO_Transport::messaging_object(), TAO_OutputCDR::more_fragments(), TAO_OutputCDR::request_id(), TAO_Transport::send_message(), TAO_OutputCDR::stub(), TAO_debug_level, TAO_OutputCDR::timeout(), ACE_OutputCDR::total_length(), and CORBA::ULong.

00029 {
00030   if (this->transport_ == 0)
00031     return 0;  // No transport.  Can't fragment.
00032 
00033   CORBA::Octet major = 0;
00034   CORBA::Octet minor = 0;
00035 
00036   (void) cdr.get_version (major, minor);
00037 
00038   // GIOP fragments are supported in GIOP 1.1 and better, but TAO only
00039   // supports them in 1.2 or better since GIOP 1.1 fragments do not
00040   // have a fragment message header.
00041   if (major == 1 && minor < 2)
00042     return -1;
00043 
00044   // Determine increase in CDR stream length if pending data is
00045   // marshaled, taking into account the alignment for the given data
00046   // type.
00047   ACE_CDR::ULong const total_pending_length =
00048     ACE_align_binary (cdr.total_length (), pending_alignment)
00049     + pending_length;
00050 
00051   // Except for the last fragment, fragmented GIOP messages must
00052   // always be aligned on an 8-byte boundary.  Padding will be added
00053   // if necessary.
00054   ACE_CDR::ULong const aligned_length =
00055     ACE_align_binary (total_pending_length, ACE_CDR::MAX_ALIGNMENT);
00056 
00057   // this->max_message_size_ must be >= 24 bytes, i.e.:
00058   //   12 for GIOP protocol header
00059   //  + 4 for GIOP fragment header
00060   //  + 8 for payload (including padding)
00061   // since fragments must be aligned on an 8 byte boundary.
00062   if (aligned_length > this->max_message_size_)
00063     {
00064       // Pad the outgoing fragment if necessary.
00065       if (cdr.align_write_ptr (ACE_CDR::MAX_ALIGNMENT) != 0)
00066         return -1;
00067 
00068       // More fragments to come.
00069       cdr.more_fragments (true);
00070 
00071       if (TAO_debug_level > 0)
00072         ACE_DEBUG ((LM_DEBUG,
00073                     "TAO (%P|%t) - On_Demand_Fragmentation_Strategy::fragment, "
00074                     "sending fragment of size %d\n",
00075                     cdr.total_length ()));
00076 
00077       // Send the current CDR stream contents through the transport,
00078       // making sure to switch on the the GIOP flags "more fragments"
00079       // bit.
00080       if (this->transport_->send_message (cdr,
00081                                           cdr.stub (),
00082                                           cdr.message_semantics (),
00083                                           cdr.timeout ()) == -1
00084 
00085           // Now generate a fragment header.
00086           || this->transport_->messaging_object ()->generate_fragment_header (
00087                cdr,
00088                cdr.request_id ()) != 0)
00089         return -1;
00090     }
00091 
00092   return 0;
00093 }

void TAO_On_Demand_Fragmentation_Strategy::operator= ( TAO_On_Demand_Fragmentation_Strategy const & ) [private]

Member Data Documentation

Generated on Thu Nov 9 12:22:38 2006 for TAO by

1.3.6


Public Member Functions
	TAO_On_Demand_Fragmentation_Strategy (TAO_Transport *transport, ACE_CDR::ULong max_message_size)
	Constructor.
virtual	~TAO_On_Demand_Fragmentation_Strategy (void)
virtual int	fragment (TAO_OutputCDR &cdr, ACE_CDR::ULong pending_alignment, ACE_CDR::ULong pending_length)
	Fragment the (potentially partially) encoded GIOP message.
Private Member Functions
	TAO_On_Demand_Fragmentation_Strategy (TAO_On_Demand_Fragmentation_Strategy const &)
void	operator= (TAO_On_Demand_Fragmentation_Strategy const &)
Private Attributes
TAO_Transport *const	transport_
	Pointer to the underlying transport object.
ACE_CDR::ULong const	max_message_size_
	Size of GIOP message at which fragmentation will occur.

TAO_On_Demand_Fragmentation_Strategy Class Reference

Public Member Functions

Private Member Functions

Private Attributes

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation