TAO/tao/Resume_Handle.h

   1 // -*- C++ -*-
   2
   3 //=============================================================================
   4 /**
   5  *  @file Resume_Handle.h
   6  *
   7  *  @author Balachandran Natarajan <bala@cs.wustl.edu>
   8  */
   9 //=============================================================================
  10
  11 #ifndef TAO_RESUME_HANDLE_H
  12 #define TAO_RESUME_HANDLE_H
  13
  14 #include /**/ "ace/pre.h"
  15
  16 #include /**/ "tao/TAO_Export.h"
  17
  18 #if !defined (ACE_LACKS_PRAGMA_ONCE)
  19 # pragma once
  20 #endif /* ACE_LACKS_PRAGMA_ONCE */
  21
  22 #include /**/ "tao/Versioned_Namespace.h"
  23
  24 TAO_BEGIN_VERSIONED_NAMESPACE_DECL
  25
  26 class TAO_ORB_Core;
  27
  28 /**
  29  * @class TAO_Resume_Handle
  30  *
  31  * @brief A utility class that helps in resuming handlers if TAO uses
  32  *  a TP Reactor from ACE.
  33  *
  34  * Please read the documentation in the bugzilla #575 in the bugzilla
  35  * database what we mean by handler resumption.
  36  *
  37  * When TAO uses a TP reactor, it takes care of resuming the handler
  38  * once it makes sure that it has read the whole message out of the
  39  * socket. During the process of reading the transport object would
  40  * have to deal with errors in 'read' from the socket, or errors in
  41  * the messages that has been received. Instead of calling
  42  * resume_handler () on the reactor at every point in the code, we
  43  * use this utility class to take care of the resumption.
  44  */
  45 class TAO_Export TAO_Resume_Handle
  46 {
  47 public:
  48   /// Constructor.
  49   TAO_Resume_Handle (TAO_ORB_Core *orb_core = 0,
  50                      ACE_HANDLE h = ACE_INVALID_HANDLE);
  51   /// Destructor
  52   ~TAO_Resume_Handle ();
  53
  54   enum TAO_Handle_Resume_Flag
  55   {
  56     TAO_HANDLE_RESUMABLE = 0,
  57     TAO_HANDLE_ALREADY_RESUMED,
  58     TAO_HANDLE_LEAVE_SUSPENDED
  59   };
  60
  61   /// Allow the users of this class to change the underlying flag.
  62   void set_flag (TAO_Handle_Resume_Flag fl);
  63
  64   /// Assignment operator
  65   TAO_Resume_Handle &operator= (const TAO_Resume_Handle &rhs);
  66
  67   /// Resume the handle in the reactor only if the ORB uses a TP
  68   /// reactor. Else we don't resume the handle.
  69   void resume_handle ();
  70
  71   /// Hook method called at the end of a connection handler's
  72   /// handle_input function.  Might override the handle_input
  73   /// return value or change the resume_handler's flag_ value.
  74   void handle_input_return_value_hook (int& return_value);
  75
  76 private:
  77   /// Our ORB Core.
  78   TAO_ORB_Core *orb_core_;
  79
  80   /// The actual handle that needs resumption..
  81   ACE_HANDLE handle_;
  82
  83   /// The flag for indicating whether the handle has been resumed or
  84   /// not. A value of '0' indicates that the handle needs resumption.
  85   TAO_Handle_Resume_Flag flag_;
  86 };
  87
  88 TAO_END_VERSIONED_NAMESPACE_DECL
  89
  90 #if defined (__ACE_INLINE__)
  91 # include "tao/Resume_Handle.inl"
  92 #endif /* __ACE_INLINE__ */
  93
  94 #include /**/ "ace/post.h"
  95
  96 #endif /*TAO_RESUME_HANDLE*/