TAO/tao/Service_Context.h

   1 // -*- C++ -*-
   2
   3 // ===================================================================
   4 /**
   5  *  @file   Service_Context.h
   6  *
   7  *  @author Balachandran Natarajan <bala@cs.wustl.edu>
   8  */
   9 // ===================================================================
  10
  11 #ifndef TAO_SERVICE_CONTEXT_H
  12 #define TAO_SERVICE_CONTEXT_H
  13
  14 #include /**/ "ace/pre.h"
  15
  16 #include "tao/IOPC.h"
  17
  18 #if !defined (ACE_LACKS_PRAGMA_ONCE)
  19 # pragma once
  20 #endif /* ACE_LACKS_PRAGMA_ONCE */
  21
  22 TAO_BEGIN_VERSIONED_NAMESPACE_DECL
  23
  24 namespace TAO
  25 {
  26   namespace CSD
  27   {
  28     class FW_Server_Request_Wrapper;
  29   }
  30 }
  31
  32 /**
  33  * @class TAO_Service_Context
  34  *
  35  * @brief Helper class for managing the service context list
  36  *  information.
  37  *
  38  * This class is used to manipulate and access the service context
  39  * list that is passed around with every GIOP request/reply. The
  40  * definition of the service context list is simply a sequence of the
  41  * following structures:
  42  * typedef unsigned long ServiceId;
  43  * struct ServiceContext
  44  * {
  45  *   ServiceId          context_id;
  46  *   sequence <octet>   context_data;
  47  * };
  48  * typedef sequence <ServiceContext> ServiceContextList;
  49  *
  50  * the real motivation behind this class is to consolidate all the
  51  * marshalling and unmarshalling information pertaining to service
  52  * context list
  53  *
  54  * @note Somewhere down the line we may want to use this class for
  55  * fast access to the info that we need from the Service Context
  56  * List.
  57  */
  58 class TAO_Export TAO_Service_Context
  59 {
  60 public:
  61   /// Declare FW_Server_Request_Wrapper a friend
  62   /// This friendship makes the FW_Server_Request_Wrapper be able to
  63   /// clone the TAO_Service_Context data member in TAO_ServerRequest.
  64   friend class TAO::CSD::FW_Server_Request_Wrapper;
  65
  66   /// Constructor
  67   TAO_Service_Context ();
  68
  69   /// = Generic components
  70
  71   /// Insert the component into the list, making a copy of the octet
  72   /// sequence.
  73   void set_context (const IOP::ServiceContext &context);
  74
  75   /// Insert the component into the list, making a copy of the octet
  76   /// sequence.  Search the list before insertion so that the
  77   /// insertion does not cause a duplicate context to be in the list.
  78   /// If the replace flag is true, update the specified context.
  79   /// Return 0 if the component was present and the replace flag
  80   /// was not set to true.
  81   int set_context (const IOP::ServiceContext &context, CORBA::Boolean replace);
  82
  83   /// Insert the component into the list, but efficiently stealing the
  84   /// contents of the octet sequence.
  85   void set_context (IOP::ServiceContext &context);
  86
  87   /// Get a copy of the context identified by <context.context_id>, return
  88   /// 0 if the component is not present.
  89   int get_context (IOP::ServiceContext &context) const;
  90
  91   /// Get a reference to a context identified by id, return
  92   /// 0 if the component is not present.
  93   int get_context (IOP::ServiceId id, const IOP::ServiceContext **context) const;
  94
  95   /// Get a copy of the Service Context corresponding to the given
  96   /// ServiceId.  The caller owns the returned Service Context.
  97   /**
  98    * @return 0 If a Service Context with the given ServiceId doesn't
  99    *           exist.
 100    */
 101   int get_context (IOP::ServiceId id, IOP::ServiceContext_out context);
 102
 103   /// Set the context from the CDR stream and add that to the service
 104   /// Context list
 105   void set_context (IOP::ServiceId id, TAO_OutputCDR &cdr);
 106
 107   /// Set the context from the CDR stream and return the context back
 108   /// to the caller. *Does not* modify the underlying service context
 109   /// list.
 110   void set_context (IOP::ServiceContext &context, TAO_OutputCDR &cdr);
 111
 112   /// Is the @a id available in the underlying service context list? If
 113   /// so return true, else return false
 114   bool is_service_id (IOP::ServiceId id);
 115
 116   /// = Marshaling and demarshaling the list
 117   int encode (TAO_OutputCDR& cdr) const;
 118   int decode (TAO_InputCDR& cdr);
 119
 120   /// Return the underlying service context list
 121   IOP::ServiceContextList &service_info ();
 122
 123   /// @note This method is only for backward comptiblity. We
 124   /// need to get this removed once RT folks have their service
 125   /// addition info done through this interface
 126   const IOP::ServiceContextList &service_info () const;
 127
 128 private:
 129   /// Helper methods to implement set_context()
 130   void set_context_i (const IOP::ServiceContext &context);
 131   void set_context_i (IOP::ServiceContext &context);
 132   void add_context_i (const IOP::ServiceContext &context);
 133   void add_context_i (IOP::ServiceContext &context);
 134   void set_context_i (IOP::ServiceId id, TAO_OutputCDR &cdr);
 135   void set_context_i (IOP::ServiceContext &context, TAO_OutputCDR &cdr);
 136
 137   /// Helper methods to implement get_context()
 138   int get_context_i (IOP::ServiceContext &context) const;
 139
 140   // Prevent copying
 141   TAO_Service_Context (const TAO_Service_Context &);
 142   TAO_Service_Context &operator= (const TAO_Service_Context &);
 143
 144 private:
 145   /// The ServiceContextList info.
 146   IOP::ServiceContextList service_context_;
 147 };
 148
 149 TAO_END_VERSIONED_NAMESPACE_DECL
 150
 151 #if defined (__ACE_INLINE__)
 152 # include "tao/Service_Context.inl"
 153 #endif /* ! __ACE_INLINE__ */
 154
 155 #include /**/ "ace/post.h"
 156
 157 #endif  /* TAO_SERVICE_CONTEXT_H */