TAO/tests/POA/Loader/Servant_Locator.cpp

   1
   2 //=============================================================================
   3 /**
   4  *  @file     Servant_Locator.cpp
   5  *
   6  *   Implementation of ServantLocator class, used with a POA
   7  *   having a NON_RETAIN policy.
   8  *
   9  *  @author  Kirthika Parameswaran <kirthika@cs.wustl.edu>
  10  */
  11 //=============================================================================
  12
  13
  14 #include "Servant_Locator.h"
  15 #include "ace/OS_NS_string.h"
  16
  17 // Initialization.The dllname is used by the Loactor to load it into
  18 // memory. The factory function is the point of entry into the dll and
  19 // is used for obtaining the servant. The garbage_collection_function
  20 // is used to kill the servant.
  21
  22 ServantLocator::ServantLocator (CORBA::ORB_ptr orb,
  23                                 const ACE_TCHAR *dllname,
  24                                 const ACE_TCHAR *factory_function,
  25                                 const ACE_TCHAR *garbage_collection_function)
  26   : orb_ (CORBA::ORB::_duplicate (orb))
  27 {
  28   // The dll is opened using the dllname passed.
  29   if (this->dll_.open (dllname) == -1)
  30     ACE_ERROR ((LM_ERROR,
  31                 "%p",
  32                 this->dll_.error ()));
  33
  34   // Obtain the symbol for the function that will get the servant
  35   // object.
  36
  37   //
  38   // Cannot go from void* to function pointer directly. Cast the void*
  39   // to long first.
  40   //
  41   void *symbol = this->dll_.symbol (factory_function);
  42   intptr_t function = reinterpret_cast<intptr_t> (symbol);
  43
  44   servant_supplier_ =
  45     reinterpret_cast<SERVANT_FACTORY> (function);
  46
  47   // Obtain the symbol for the function which will destroy the
  48   // servant.
  49   symbol = this->dll_.symbol (garbage_collection_function);
  50   function = reinterpret_cast<intptr_t> (symbol);
  51
  52   servant_garbage_collector_ =
  53     reinterpret_cast<SERVANT_GARBAGE_COLLECTOR> (function);
  54 }
  55
  56 // This method associates an servant with the ObjectID.
  57
  58 PortableServer::Servant
  59 ServantLocator::preinvoke (const PortableServer::ObjectId &oid,
  60                            PortableServer::POA_ptr poa,
  61                            const char * /* operation */,
  62                            PortableServer::ServantLocator::Cookie &cookie)
  63 {
  64   PortableServer::Servant servant =
  65     (*servant_supplier_) (oid,
  66                           poa,
  67                           this->orb_.in ());
  68   if (servant != 0)
  69     {
  70       // Return the servant as the cookie , used as a check when
  71       // postinvoke is called on this ServantLocator.
  72
  73       cookie = servant;
  74       return servant;
  75     }
  76   else
  77     throw CORBA::OBJECT_NOT_EXIST ();
  78 }
  79
  80 // Since the servant gets invoked per operation, the servant has to be
  81 // destroyed per operation too.  This is accomplished in the
  82 // postinvoke method.
  83
  84 void
  85 ServantLocator::postinvoke (const PortableServer::ObjectId &oid,
  86                             PortableServer::POA_ptr poa ,
  87                             const char * /* operation */,
  88                             PortableServer::ServantLocator::Cookie cookie,
  89                             PortableServer::Servant servant)
  90 {
  91   // Check the passed servant with the cookie.
  92   PortableServer::Servant my_servant =
  93     reinterpret_cast<PortableServer::Servant> (cookie);
  94
  95   ACE_ASSERT (servant == my_servant);
  96
  97   // Invoke the garbage_collection_function.
  98   (*servant_garbage_collector_) (oid,
  99                                  poa,
 100                                  servant);
 101
 102   // To avoid warning about unused variable with ACE_NDEBUG.
 103   ACE_UNUSED_ARG (my_servant);
 104 }