TAO/tao/PI_Server/PICurrent_Guard.h

   1 // -*- C++ -*-
   2
   3 // ===================================================================
   4 /**
   5  *  @file   PICurrent_Guard.h
   6  *
   7  *  @author Ossama Othman <ossama@dre.vanderbilt.edu>
   8  */
   9 // ===================================================================
  10
  11 #ifndef TAO_PI_CURRENT_GUARD_H
  12 #define TAO_PI_CURRENT_GUARD_H
  13
  14 #include /**/ "ace/pre.h"
  15
  16 #include "tao/PI_Server/pi_server_export.h"
  17
  18 #if !defined (ACE_LACKS_PRAGMA_ONCE)
  19 # pragma once
  20 #endif /* ACE_LACKS_PRAGMA_ONCE */
  21
  22 #include "tao/orbconf.h"
  23
  24 #if TAO_HAS_INTERCEPTORS == 1
  25
  26 TAO_BEGIN_VERSIONED_NAMESPACE_DECL
  27
  28 /// Forward declarations.
  29 class TAO_ServerRequest;
  30
  31 namespace TAO
  32 {
  33   class PICurrent_Impl;
  34
  35   /**
  36    * @class PICurrent_Guard
  37    *
  38    * @brief Class used to make copying between request scope current
  39    *        and thread scope current exception-safe.
  40    *
  41    * Since copies between the request scope current and thread scope
  42    * current must also occur if an exception is thrown, e.g. made
  43    * available to the send_exception() interception points, the
  44    * "guard" idiom is used to make this action exception-safe.
  45    *
  46    * @note This Guard class is only used on the server side.
  47    */
  48   class PICurrent_Guard
  49   {
  50   public:
  51     /// Constructor
  52     /**
  53      * This constructor sets up this guard to copy the data held in a
  54      * given PICurrent when transitioning from that PICurrent's scope
  55      * to another scope (e.g. request scope to thread scope transition
  56      * immediately following receive_request_service_contexts() on
  57      * server side).
  58      *
  59      * @param tsc_to_rsc true when copying TSC slot table to RSC slot
  60      *                        table, i.e. after target operation
  61      *                        completes.
  62      */
  63     PICurrent_Guard (TAO_ServerRequest &server_request,
  64                      bool tsc_to_rsc);
  65
  66     /// Destructor
  67     /**
  68      * The destructor copies (a logical copy whenever possible) data
  69      * held in a given PICurrent when transitioning from one PICurrent
  70      * scope to another immediately before any ending interception
  71      * points are invoked, and after the starting and intermediate (if
  72      * any) interception points are invoked.
  73      */
  74     ~PICurrent_Guard ();
  75
  76   private:
  77     /// The PICurrent implementation whose slot table will be copied.
  78     PICurrent_Impl *src_;
  79
  80     /// The PICurrent implementation whose slot table will be filled
  81     /// with the contents of another PICurrent's slot table.
  82     PICurrent_Impl *dest_;
  83   };
  84 }
  85
  86 TAO_END_VERSIONED_NAMESPACE_DECL
  87
  88 #endif  /* TAO_HAS_INTERCEPTORS == 1 */
  89
  90 #include /**/ "ace/post.h"
  91
  92 #endif /* TAO_PI_CURRENT_GUARD_H */