path: root/TAO/tao/Pluggable.h

// This may look like C, but it's really -*- C++ -*-
// $Id$

// ============================================================================
//
// = LIBRARY
//     TAO
//
// = FILENAME
//     Pluggable.h
//
// = DESCRIPTION
//     Interface for the TAO pluggable protocol framework.
//
// = AUTHOR
//     Fred Kuhns <fredk@cs.wustl.edu>
//
// ============================================================================

#ifndef TAO_PLUGGABLE_H
#define TAO_PLUGGABLE_H

#include "tao/corbafwd.h"
#include "tao/Sequence.h"
#include "tao/Typecode.h"

// Forward declarations.
class ACE_Addr;
class ACE_Reactor;
class TAO_ORB_Core;

class TAO_Stub;
class TAO_Profile;
class TAO_MProfile;
class TAO_Resource_Factory;

class TAO_Reply_Dispatcher;
class TAO_Transport_Mux_Strategy;
class TAO_Wait_Strategy;

class TAO_Export TAO_Transport
{
  // = TITLE
  //   Generic definitions for the new Transport class.
  //
  // = DESCRIPTION
  //   The transport object is created in the Service handler
  //   constructor and deleted in the service handlers destructor!!

public:
  TAO_Transport (CORBA::ULong tag,
                 TAO_ORB_Core *orb_core);
  // default creator, requres the tag value be supplied.

  virtual ~TAO_Transport (void);
  // destructor

  CORBA::ULong tag (void) const;
  // The tag, each concrete class will have a specific tag value.

  virtual void close_connection() = 0;
  // Call the corresponding connection handler's <close>
  // method.

  virtual int idle (void) = 0;
  // Idles the corresponding connection handler.

  virtual ACE_HANDLE handle (void) = 0;
  // This method provides a way to gain access to the underlying
  // file handle used by the reactor.

  virtual ssize_t send (const ACE_Message_Block *mblk,
                        ACE_Time_Value *s = 0) = 0;
  // Write the complete Message_Block chain to the connection.
  // @@ The ACE_Time_Value *s is just a place holder for now.  It is
  // not clear this this is the best place to specify this.  The actual
  // timeout values will be kept in the Policies.

  virtual ssize_t send (const u_char *buf,
                        size_t len,
                        ACE_Time_Value *s = 0) = 0;
  // Write the contents of the buffer of length len to the connection.
  // @@ The ACE_Time_Value *s is just a place holder for now.  It is
  // not clear this this is the best place to specify this.  The actual
  // timeout values will be kept in the Policies.

  virtual ssize_t send (const iovec *iov,
                        int iovcnt,
                        ACE_Time_Value *s = 0) = 0;
  // Write the contents of iovcnt iovec's to the connection.
  // @@ The ACE_Time_Value *s is just a place holder for now.  It is
  // not clear this this is the best place to specify this.  The actual
  // timeout values will be kept in the Policies.

  virtual ssize_t recv (char *buf,
                        size_t len,
                        ACE_Time_Value *s = 0) = 0;
  // Read len bytes from into buf.
  // @@ The ACE_Time_Value *s is just a place holder for now.  It is
  // not clear this this is the best place to specify this.  The actual
  // timeout values will be kept in the Policies.

  virtual ssize_t recv (char *buf,
                        size_t len,
                        int flags,
                        ACE_Time_Value *s = 0) = 0;
  // Read len bytes from into buf using flags.
  // @@ The ACE_Time_Value *s is just a place holder for now.  It is
  // not clear this this is the best place to specify this.  The actual
  // timeout values will be kept in the Policies.

  virtual ssize_t recv (iovec *iov,
                        int iovcnt,
                        ACE_Time_Value *s = 0) = 0;
  //  Read received data into the iovec buffers.
  // @@ The ACE_Time_Value *s is just a place holder for now.  It is
  // not clear this this is the best place to specify this.  The actual
  // timeout values will be kept in the Policies.

  virtual void start_request (TAO_ORB_Core *orb_core,
                              const TAO_Profile *profile,
                              const char* opname,
                              CORBA::ULong request_id,
                              CORBA::Boolean is_twoway,
                              TAO_OutputCDR &output,
                              CORBA::Environment &ACE_TRY_ENV = TAO_default_environment ())
    ACE_THROW_SPEC ((CORBA::SystemException));
  // Fill into <output> the right headers to make a request.

  virtual void start_locate (TAO_ORB_Core *orb_core,
                             const TAO_Profile *profile,
                             CORBA::ULong request_id,
                             TAO_OutputCDR &output,
                             CORBA::Environment &ACE_TRY_ENV = TAO_default_environment ())
    ACE_THROW_SPEC ((CORBA::SystemException));
  // Fill into <output> the right headers to make a locate request.

  virtual int send_request (TAO_ORB_Core *orb_core,
                            TAO_OutputCDR &stream,
                            int twoway,
                            ACE_Time_Value *max_time_wait) = 0;
  // Default action to be taken for send request.

  // = Get and set methods for the ORB Core.

  // void orb_core (TAO_ORB_Core *orb_core);
  // Set it.

  TAO_ORB_Core *orb_core (void) const;
  // Get it.

  // = Get and set methods for thr TMS object.

  // void tms(TAO_Transport_Mux_Strategy *rms);
  // Set the TMSobject.

  TAO_Transport_Mux_Strategy *tms (void) const;
  // Get the TMS used by this Transport object.

  TAO_Wait_Strategy *wait_strategy (void) const;
  // Return the Wait strategy used by the Transport.

  CORBA::ULong request_id (void);
  // Get request id for the current invocation from the TMSobject.

  int bind_reply_dispatcher (CORBA::ULong request_id,
                             TAO_Reply_Dispatcher *rd);
  // Bind the reply dispatcher with the TMS object.

  virtual int wait_for_reply (ACE_Time_Value *max_wait_time,
                              int &reply_received);
  // Wait for the reply depending on the strategy.

  virtual int handle_client_input (int block = 0,
                                   ACE_Time_Value *max_wait_time = 0);
  // Read and handle the reply. Returns 0 when there is Short Read on
  // the connection. Returns 1 when the full reply is read and
  // handled. Returns -1 on errors.
  // If <block> is 1, then reply is read in a blocking manner.

  virtual int register_handler (void);
  // Register the handler with the reactor. Will be called by the Wait
  // Strategy if Reactor is used  for that strategy. Default
  // implementation out here returns -1 setting <errno> to ENOTSUP.

  // = Setting the Transport object in Idle state. Theese methods are
  //   routed the TMS object. The TMS starategies implement the
  //   methods accordingly. 
  
  virtual int idle_after_send (void);
  // Request has been just sent, but the reply is not received. Idle
  // the transport now.
  
  virtual int idle_after_reply (void);
  // Request is sent and the reply is received. Idle the transport
  // now. 

  virtual int reply_received (const CORBA::ULong request_id);
  // Check with the TMS whether the reply has been receieved for the
  // request with <request_id>.

  virtual ACE_SYNCH_CONDITION *leader_follower_condition_variable (void);
  // Return the TSS leader follower condition variable used in the
  // Wait Strategy. Muxed Leader Follower implementation returns a
  // valid condition variable, others return 0.

protected:
  CORBA::ULong tag_;
  // IOP protocol tag.

  TAO_ORB_Core *orb_core_;
  // Global orbcore resource.

  TAO_Transport_Mux_Strategy *tms_;
  // Strategy to decide whether multiple requests can be sent over the
  // same connection or the connection is exclusive for a request.

  TAO_Wait_Strategy *ws_;
  // Strategy for waiting for the reply after sending the request.
};

class TAO_Export TAO_Profile
{
  // = TITLE
  //   Defines the Profile interface
  //
  // = DESCRIPTION
  //   An abstract base class for representing object address or location
  //   information.  This is based on the CORBA IOR definitions.
  //
public:
  TAO_Profile (CORBA::ULong tag);
  // Constructor

  virtual ~TAO_Profile (void);
  // If you have a virtual method you need a virtual dtor.

  CORBA::ULong tag (void) const;
  // The tag, each concrete class will have a specific tag value.

  CORBA::ULong _incr_refcnt (void);
  // Increase the reference count by one on this object.

  CORBA::ULong _decr_refcnt (void);
  // Decrement the object's reference count.  When this count goes to
  // 0 this object will be deleted.

  void forward_to (TAO_MProfile *mprofiles);
  // Keep a pointer to the forwarded profile

  TAO_MProfile* forward_to (void);
  // MProfile accessor

  virtual int parse_string (const char *string,
                            CORBA::Environment &ACE_TRY_ENV) = 0;
  // Initialize this object using the given input string.
  // Supports URL stylr of object references

  virtual CORBA::String to_string (CORBA::Environment &ACE_TRY_ENV) = 0;
  // Return a string representation for this profile.  client must
  // deallocate memory.

  virtual int decode (TAO_InputCDR& cdr) = 0;
  // Initialize this object using the given CDR octet string.

  virtual int encode (TAO_OutputCDR &stream) const = 0;
  // Encode this profile in a stream, i.e. marshal it.

  virtual const TAO_ObjectKey &object_key (void) const = 0;
  // @@ deprecated. return a reference to the Object Key.

  TAO_ObjectKey &object_key (TAO_ObjectKey& objkey);
  // @@ deprecated. set the Object Key.

  virtual TAO_ObjectKey *_key (void) const = 0;
  // Obtain the object key, return 0 if the profile cannot be parsed.
  // The memory is owned by the caller!

  virtual CORBA::Boolean is_equivalent (const TAO_Profile* other_profile) = 0;
  // Return true if this profile is equivalent to other_profile.  Two
  // profiles are equivalent iff their key, port, host, object_key and
  // version are the same.

  virtual CORBA::ULong hash (CORBA::ULong max,
                             CORBA::Environment &ACE_TRY_ENV) = 0;
  // Return a hash value for this object.

  virtual int addr_to_string(char *buffer, size_t length) = 0;
  // Return a string representation for the address.  Returns
  // -1 if buffer is too small.  The purpose of this method is to
  // provide a general interface to the underlying address object's
  // addr_to_string method.  This allowsthe protocol implementor to
  // select the appropriate string format.

  virtual void reset_hint (void) = 0;
  // This method is used with a connection has been reset requiring
  // the hint to be cleaned up and reset to NULL.

private:
  TAO_MProfile *forward_to_i (void);
  // this object keeps ownership of this object

private:
  CORBA::ULong tag_;
  // IOP protocol tag.

  TAO_MProfile* forward_to_;
  // the TAO_MProfile which contains the profiles for the forwarded
  // object.

  ACE_SYNCH_MUTEX refcount_lock_;
  // Mutex to protect reference count.

  CORBA::ULong refcount_;
  // Number of outstanding references to this object.
};

class TAO_Export TAO_Unknown_Profile : public TAO_Profile
{
  // = TITLE
  //   A TAO_Profile class to handle foreign profiles.
  //
  // = DESCRIPTION
  //   The CORBA spec implies that ORBs must be prepared to save and
  //   pass around profiles for protocols it does not recognize. It is
  //   not mandatory to *use* those profiles but they shouldn't be
  //   dropped.
  //   This class stores the information required to marshal and
  //   demarshal an unknown profile, but simply returns an error if
  //   any of the TAO internal methods are invoked.
  //
public:
  TAO_Unknown_Profile (CORBA::ULong tag);
  // Create the profile

  // = The TAO_Profile methods look above
  virtual int parse_string (const char *string,
                            CORBA::Environment &ACE_TRY_ENV);
  virtual CORBA::String to_string (CORBA::Environment &ACE_TRY_ENV);
  virtual int decode (TAO_InputCDR& cdr);
  virtual int encode (TAO_OutputCDR &stream) const;
  virtual const TAO_ObjectKey &object_key (void) const;
  virtual TAO_ObjectKey *_key (void) const;
  virtual CORBA::Boolean is_equivalent (const TAO_Profile* other_profile);
  virtual CORBA::ULong hash (CORBA::ULong max,
                             CORBA::Environment &ACE_TRY_ENV);
  virtual int addr_to_string(char *buffer, size_t length);
  virtual void reset_hint (void);

private:
  TAO_opaque body_;
};

// ****************************************************************

class TAO_Export TAO_Acceptor
{
  // = TITLE
  //   Abstract Acceptor class used for pluggable protocols.
  //
  // = DESCRIPTION
  //   Base class for the Acceptor bridge calss.
public:

  TAO_Acceptor (CORBA::ULong tag);

  virtual int create_mprofile (const TAO_ObjectKey &object_key,
                               TAO_MProfile &mprofile) = 0;
  // Create the corresponding profile for this endpoint.

  virtual int open (TAO_ORB_Core *orb_core,
                    int version_major,
                    int version_minor,
                    ACE_CString &address) = 0;
  // method to initialize acceptor for address.

  virtual int open_default (TAO_ORB_Core *orb_core) = 0;
  // Open an acceptor on the default endpoint for this protocol

  virtual ACE_Event_Handler *acceptor (void) = 0;
  // Return the ACE acceptor...

  virtual int is_collocated (const TAO_Profile* profile) = 0;
  // Return 1 if the <profile> has the same endpoint as the acceptor.

  CORBA::ULong tag (void) const;
  // The tag, each concrete class will have a specific tag value.

  virtual int close (void) = 0;
  // Closes the acceptor

  virtual CORBA::ULong endpoint_count (void) = 0;
  // returns the number of endpoints this acceptor is listening on.  This
  // is used for determining how many profiles will be generated
  // for this acceptor.

  virtual ~TAO_Acceptor (void);
  // Destructor

private:
  CORBA::ULong tag_;
  // IOP protocol tag.
};

class TAO_Export TAO_Connector
{
  // = TITLE
  //   Generic Connector interface definitions.
  //
  // = DESCRIPTION
  //   Base class for connector bridge object.
public:

  TAO_Connector (CORBA::ULong tag);
  // default constructor.

  virtual ~TAO_Connector (void);
  // the destructor.

  CORBA::ULong tag (void) const;
  // The tag identifying the specific ORB transport layer protocol.
  // For example TAO_IOP_TAG_INTERNET_IOP = 0.  The tag is used in the
  // IOR to identify the type of profile included. IOR -> {{tag0,
  // profile0} {tag1, profole1} ...}  GIOP.h defines typedef
  // CORBA::ULong TAO_IOP_Profile_ID;

  int make_mprofile (const char *ior,
                     TAO_MProfile &mprofile,
                     CORBA::Environment &ACE_TRY_ENV);
  // Parse a string containing a URL style IOR and return an
  // MProfile.

  virtual int open (TAO_ORB_Core *orb_core) = 0;
  //  Initialize object and register with reactor.

  virtual int close (void) = 0;
  // Shutdown Connector bridge and concreate Connector.

  virtual int connect (TAO_Profile *profile,
                       TAO_Transport *&,
                       ACE_Time_Value *max_wait_time) = 0;
  // To support pluggable we need to abstract away the connect()
  // method so it can be called from the GIOP code independant of the
  // actual transport protocol in use.

  virtual int preconnect (const char *preconnections) = 0;
  // Initial set of connections to be established.

  virtual TAO_Profile *create_profile (TAO_InputCDR& cdr) = 0;
  // Create a profile for this protocol and initialize it based on the
  // encapsulation in <cdr>

  virtual int check_prefix (const char *endpoint) = 0;
  // Check that the prefix of the provided endpoint is valid for use
  // with a given pluggable protocol.

  virtual char object_key_delimiter (void) const = 0;
  // Return the object key delimiter to use or expect.

protected:
  virtual void make_profile (const char *endpoint,
                             TAO_Profile *&,
                             CORBA::Environment &ACE_TRY_ENV) = 0;
  // Create a profile with a given endpoint.

private:
  CORBA::ULong tag_;
  // IOP protocol tag.
};

#if defined (__ACE_INLINE__)
# include "tao/Pluggable.i"
#endif /* __ACE_INLINE__ */

#endif  /* TAO_PLUGGABLE_H */