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// This may look like C, but it's really -*- C++ -*-
// -*- C++ -*-
// ===================================================================
/**
* @file GIOP_Message_Handler.h
*
* $Id$
*
* @author Balachandran Natarajan <bala@cs.wustl.edu>
**/
// ===================================================================
#ifndef TAO_GIOP_MESSAGE_HANDLER_H
#define TAO_GIOP_MESSAGE_HANDLER_H
#include "ace/pre.h"
#include "ace/Message_Block.h"
#if !defined (ACE_LACKS_PRAGMA_ONCE)
# pragma once
#endif /* ACE_LACKS_PRAGMA_ONCE */
#include "tao/GIOP_Message_State.h"
class TAO_Transport;
class TAO_ORB_Core;
class TAO_GIOP_Message_Base;
enum TAO_GIOP_Message_Status
{
/// The buffer is waiting for the header of the message yet
TAO_GIOP_WAITING_FOR_HEADER = 0,
/// The buffer is waiting for the payload to appear on the socket
TAO_GIOP_WAITING_FOR_PAYLOAD,
/// The buffer has got multiple messages
TAO_GIOP_MULTIPLE_MESSAGES
};
enum TAO_Message_Block_Content_Status
{
/// The buffer has nomore info for processing ie. all information
/// have been processed
TAO_MESSAGE_BLOCK_COMPLETE = 3,
/// The buffer has something meaningful and needs processing
TAO_MESSAGE_BLOCK_NEEDS_PROCESSING,
/// The buffer has nothing meaningful. Need to read more data from
/// the socket to make the reamaining data meaningful
TAO_MESSAGE_BLOCK_INCOMPLETE
};
/**
* @class TAO_GIOP_Message_Handler
*
* @brief GIOP specific message handler class
*
* This class does some of the message handling for GIOP. This class
* reads the message from the socket, splits the messages to create a
* CDR stream out of it and passes that to the higher layers of the ORB.
* The read from the socket is done using a single 'read' instead of
* reading the header and the payload seperately.
*/
class TAO_GIOP_Message_Handler
{
public:
/// Ctor
TAO_GIOP_Message_Handler (TAO_ORB_Core *orb_core,
TAO_GIOP_Message_Base *base,
size_t input_cdr_size = ACE_CDR::DEFAULT_BUFSIZE);
/// Read the message from the transport in to the
/// <current_buffer_>. This method delegates responsibility of
/// parsing to some of the helper methods.
int read_parse_message (TAO_Transport *transport);
/// Check whether we have atleast one complete message ready for
/// processing.
int is_message_ready (TAO_Transport *transport);
/// Do we have more messages for processing?
int more_messages (void);
/// Reset the contents of the <current_buffer_> if no more requests
/// need to be processed. We reset the contents of the
/// <message_state_> to parse and process the next request.
void reset (int reset_flag = 0);
/// Return the underlying message state
TAO_GIOP_Message_State &message_state (void);
/// Return the pointer to the data block within the message block
ACE_Data_Block *data_block (void) const;
/// Return the underlying data block of the <current_buffer_>. At
/// the sametime making a new data_block for itself. The read and
/// write pointer positions would be reset.
ACE_Data_Block *steal_data_block (void);
/// Return the rd_ptr of the <current_buffer_>
char *rd_ptr (void) const;
/// Return the position of the read pointer in the <current_buffer_>
size_t rd_pos (void) const;
/// Return the position of the write pointer in the <current_buffer_>
size_t wr_pos (void) const;
private:
/// Parses the header information from the <current_buffer_>.
int parse_header (void);
/// Validates the first 4 bytes that contain the magic word
/// "GIOP". Also calls the validate_version () on the incoming
/// stream.
int parse_magic_bytes (void);
/// Gets the size of the payload from the <current_buffer_>. If the
/// size of the current buffer is less than the payload size, the
/// size of the buffer is increased.
CORBA::ULong get_payload_size (void);
/// Extract a CORBA::ULong from the <current_buffer_>
CORBA::ULong read_ulong (const char *buf);
/// Get the next message from the <supp_buffer_> in to the
/// <current_buffer_>
int get_message (void);
/// Reads the message from the <transport> and sets the <wr_ptr> of
/// the buffer appropriately.
int read_messages (TAO_Transport *transport);
private:
/// The pointer to the object that holds us
TAO_GIOP_Message_Base *mesg_base_;
/// The state of the message in the buffer
TAO_GIOP_Message_Status message_status_;
/// The size of the message that is being read of the socket. This
/// value is originally set to 1024 bytes. It is reset if we start
/// receiving messages with payloads greater than that. The current
/// value of <message_size_> would be the size of the last message
/// received (ie. payload+headers).
size_t message_size_;
/// The buffer. rd_ptr() points to the beginning of the current
/// message, properly aligned wr_ptr() points to where the next
/// read() should put the data.
ACE_Message_Block current_buffer_;
/// The supplementary buffer that holds just one message if the
/// <current_buffer_> has more than one message. One message from
/// the <current_buffer_> is taken and filled in this buffer, which
/// is then sent to the higher layers of the ORB.
ACE_Message_Block supp_buffer_;
/// The message state. It represents the status of the messages that
/// have been read from the current_buffer_
TAO_GIOP_Message_State message_state_;
/// Our copy the ORB_Core
TAO_ORB_Core *orb_core_;
};
const size_t TAO_GIOP_MESSAGE_HEADER_LEN = 12;
const size_t TAO_GIOP_MESSAGE_SIZE_OFFSET = 8;
const size_t TAO_GIOP_MESSAGE_FLAGS_OFFSET = 6;
const size_t TAO_GIOP_MESSAGE_TYPE_OFFSET = 7;
const size_t TAO_GIOP_VERSION_MINOR_OFFSET = 5;
const size_t TAO_GIOP_VERSION_MAJOR_OFFSET = 4;
const size_t TAO_GIOP_MESSAGE_FRAGMENT_HEADER = 4;
#if defined (__ACE_INLINE__)
# include "tao/GIOP_Message_Handler.inl"
#endif /* __ACE_INLINE__ */
#include "ace/post.h"
#endif /*TAO_GIOP_MESSAGE_HANDLER_H*/
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