ChangeLogTag: Mon Jun 26 09:15:00 UTC 2006 Simon Massey <sma@prismtech.com>

8 files changed, 109 insertions, 322 deletions

diff --git a/TAO/tao/PI/ClientRequestInfo.cpp b/TAO/tao/PI/ClientRequestInfo.cpp
index d2af5d9a2e5..f3df9f77449 100644
--- a/TAO/tao/PI/ClientRequestInfo.cpp
+++ b/TAO/tao/PI/ClientRequestInfo.cpp
@@ -29,8 +29,7 @@ TAO_BEGIN_VERSIONED_NAMESPACE_DECL
 
 TAO_ClientRequestInfo::TAO_ClientRequestInfo (TAO::Invocation_Base *inv)
   : invocation_ (inv),
-    rs_pi_current_ (),
-    copy_callback_ ()
+    rs_pi_current_ ()
 {
   this->setup_picurrent ();
 }
@@ -55,19 +54,7 @@ TAO_ClientRequestInfo::setup_picurrent (void)
       if (tsc != 0)
         {
           // Logically copy the TSC's slot table to the RSC.
-          this->rs_pi_current_.lc_slot_table (tsc);
-
-          // PICurrent will potentially have to call back on the request
-          // scope current so that it can deep copy the contents of the
-          // thread scope current if the contents of the thread scope
-          // current are about to be modified.  It is necessary to do this
-          // deep copy once in order to completely isolate the request
-          // scope current from the thread scope current.  This is only
-          // necessary, if the thread scope current is modified after its
-          // contents have been *logically* copied to the request scope
-          // current.
-          this->copy_callback_.src_and_dst (tsc, &this->rs_pi_current_);
-          tsc->copy_callback (&this->copy_callback_);
+          this->rs_pi_current_.take_lazy_copy (tsc);
        }
     }
 }
diff --git a/TAO/tao/PI/ClientRequestInfo.h b/TAO/tao/PI/ClientRequestInfo.h
index 40c83ff4c70..4671889f2b1 100644
--- a/TAO/tao/PI/ClientRequestInfo.h
+++ b/TAO/tao/PI/ClientRequestInfo.h
@@ -35,7 +35,6 @@
 #include "tao/PI/ClientRequestInfoC.h"
 #include "tao/PI/PIForwardRequestC.h"
 #include "tao/PI/PICurrent_Impl.h"
-#include "tao/PI/PICurrent_Copy_Callback.h"
 #include "tao/CORBA_methods.h"
 #include "tao/ORB_Constants.h"
 #include "tao/LocalObject.h"
@@ -274,22 +273,6 @@ private:
   /// The "Request Scope Current" (RSC) object, as required by
   /// Portable Interceptors.
   TAO::PICurrent_Impl rs_pi_current_;
-
-  /// Callback object to be executed when shallow copied slot table
-  /// must be deep copied.
-  /**
-   * This callback object deep copies the slot table from the TSC to
-   * the RSC.
-   * @par
-   * As an optimization, the TSC's slot table is initially only
-   * shallowed copied to the RSC.  If the TSC's slot table will be
-   * modified, e.g. via PICurrent::set_slot(), it's slot table must be
-   * deep copied to the RSC before actually modifying that slot
-   * table.  This is necessary since the RSC is read-only on the
-   * client side, meaning that changes in the TSC that occur after
-   * instantiation of the RSC must not be reflected in the RSC.
-   */
-  TAO::PICurrent_Copy_Callback copy_callback_;
 };
 
 TAO_END_VERSIONED_NAMESPACE_DECL
diff --git a/TAO/tao/PI/PICurrent.h b/TAO/tao/PI/PICurrent.h
index 1425f5eec74..6f50a5d93da 100644
--- a/TAO/tao/PI/PICurrent.h
+++ b/TAO/tao/PI/PICurrent.h
@@ -42,7 +42,6 @@ class TAO_ORB_Core;
 
 namespace TAO
 {
-  class PICurrent_Copy_Callback;
   class PICurrent_Impl;
 
   /**
diff --git a/TAO/tao/PI/PICurrent_Copy_Callback.cpp b/TAO/tao/PI/PICurrent_Copy_Callback.cpp
deleted file mode 100644
index 9332b9c986a..00000000000
--- a/TAO/tao/PI/PICurrent_Copy_Callback.cpp
+++ /dev/null
@@ -1,67 +0,0 @@
-#include "tao/PI/PICurrent_Copy_Callback.h"
-
-#if TAO_HAS_INTERCEPTORS == 1
-
-#include "tao/PI/PICurrent_Impl.h"
-
-ACE_RCSID (tao,
-           PICurrent_Copy_Callback,
-           "$Id$")
-
-
-TAO_BEGIN_VERSIONED_NAMESPACE_DECL
-
-TAO::PICurrent_Copy_Callback::PICurrent_Copy_Callback (void)
-  : src_ (0),
-    dst_ (0)
-{
-}
-
-TAO::PICurrent_Copy_Callback::~PICurrent_Copy_Callback (void)
-{
-  // Disable copy callbacks through this callback object in the source
-  // PICurrent_Impl object to prevent the source PICurrent_Impl from
-  // potentially calling back on a destructed copy callback object.
-  if (this->src_ != 0)
-    this->src_->copy_callback (0);
-}
-
-void
-TAO::PICurrent_Copy_Callback::execute (void)
-{
-  if (this->src_ != 0 && this->dst_ != 0
-      && this->src_ != this->dst_)
-    {
-      // Only do a copy when the destination still refers to the table
-      // of the src
-      if (this->dst_->lc_slot_table () != 0)
-        {
-          const PICurrent_Impl::Table & s = this->src_->current_slot_table ();
-
-          // Disable use of the logically copied slot table before
-          // performing the deep copy.
-          this->dst_->lc_slot_table (0);
-
-          PICurrent_Impl::Table & d = this->dst_->slot_table ();
-
-          d = s;
-        }
-
-      // Prevent subsequent deep copies, effectively disabling this
-      // callback.
-      this->src_->copy_callback (0);
-      this->src_->destruction_callback (0);
-    }
-}
-
-void
-TAO::PICurrent_Copy_Callback::src_and_dst (PICurrent_Impl * src,
-                                           PICurrent_Impl * dst)
-{
-  this->src_ = src;
-  this->dst_ = dst;
-}
-
-TAO_END_VERSIONED_NAMESPACE_DECL
-
-#endif  /* TAO_HAS_INTERCEPTORS == 1 */
diff --git a/TAO/tao/PI/PICurrent_Copy_Callback.h b/TAO/tao/PI/PICurrent_Copy_Callback.h
deleted file mode 100644
index 76f550e652f..00000000000
--- a/TAO/tao/PI/PICurrent_Copy_Callback.h
+++ /dev/null
@@ -1,80 +0,0 @@
-// -*- C++ -*-
-
-// ===================================================================
-/**
- *  @file   PICurrent_Copy_Callback.h
- *
- *  $Id$
- *
- *  @author Ossama Othman <ossama@dre.vanderbilt.edu>
- */
-// ===================================================================
-
-#ifndef TAO_PI_CURRENT_CALLBACK_H
-#define TAO_PI_CURRENT_CALLBACK_H
-
-#include /**/ "ace/pre.h"
-
-#include "tao/PI/pi_export.h"
-
-#if !defined (ACE_LACKS_PRAGMA_ONCE)
-# pragma once
-#endif /* ACE_LACKS_PRAGMA_ONCE */
-
-#include "tao/orbconf.h"
-
-#if TAO_HAS_INTERCEPTORS == 1
-
-
-TAO_BEGIN_VERSIONED_NAMESPACE_DECL
-
-namespace TAO
-{
-  class PICurrent_Impl;
-
-  /**
-   * @class PICurrent_Copy_Callback
-   *
-   * @brief PICurrent copy callback class.
-   *
-   * This class performs deep copies from the source PICurrent_Impl
-   * object's slot table to the destination PICurrent_Impl object's
-   * slot table.
-   */
-  class TAO_PI_Export PICurrent_Copy_Callback
-  {
-  public:
-
-    /// Constructor.
-    PICurrent_Copy_Callback (void);
-
-    /// Destructor.
-    ~PICurrent_Copy_Callback (void);
-
-    /// Perform the copy.
-    void execute (void);
-
-    /// Set the source and destination PICurrent_Impl objects.
-    void src_and_dst (PICurrent_Impl * src, PICurrent_Impl * dst);
-
-  private:
-    /// Disallow copying and assignment.
-    PICurrent_Copy_Callback (const PICurrent_Copy_Callback &);
-    PICurrent_Copy_Callback &operator= (const PICurrent_Copy_Callback &);
-
-    /// Source PICurrent from which copies will be made.
-    PICurrent_Impl * src_;
-
-    /// Destination PICurrent to which copies will be made.
-    PICurrent_Impl * dst_;
-
-  };
-}
-
-TAO_END_VERSIONED_NAMESPACE_DECL
-
-#endif  /* TAO_HAS_INTERCEPTORS == 1 */
-
-#include /**/ "ace/post.h"
-
-#endif /* TAO_PI_CURRENT_CALLBACK_H */
diff --git a/TAO/tao/PI/PICurrent_Impl.cpp b/TAO/tao/PI/PICurrent_Impl.cpp
index 4aa071e258c..7cb54b6df2c 100644
--- a/TAO/tao/PI/PICurrent_Impl.cpp
+++ b/TAO/tao/PI/PICurrent_Impl.cpp
@@ -11,8 +11,6 @@ ACE_RCSID (tao,
 # include "tao/PI/PICurrent_Impl.inl"
 #endif /* __ACE_INLINE__ */
 
-#include "tao/PI/PICurrent_Copy_Callback.h"
-
 #include "tao/TAO_Server_Request.h"
 #include "tao/SystemException.h"
 #include "ace/Log_Msg.h"
@@ -20,24 +18,6 @@ ACE_RCSID (tao,
 
 TAO_BEGIN_VERSIONED_NAMESPACE_DECL
 
-TAO::PICurrent_Impl::PICurrent_Impl (void)
-  : slot_table_ (),
-    lc_slot_table_ (0),
-    copy_callback_ (0),
-    destruction_callback_ (0)
-{
-}
-
-TAO::PICurrent_Impl::~PICurrent_Impl (void)
-{
-  // Break any existing ties with PICurrent to which our table was
-  // logically copied since our table no longer exists once this
-  // destructor completes.
-  if (this->destruction_callback_ != 0)
-    this->destruction_callback_->execute_destruction_callback (0);
-}
-
-
 CORBA::Any *
 TAO::PICurrent_Impl::get_slot (PortableInterceptor::SlotId identifier
                                ACE_ENV_ARG_DECL)
@@ -47,17 +27,17 @@ TAO::PICurrent_Impl::get_slot (PortableInterceptor::SlotId identifier
   // No need to check validity of SlotId.  It is validated before this
   // method is invoked.
 
-  // Get the slot table that is currently active
-  PICurrent_Impl::Table & table = this->current_slot_table ();
-
   // The active slot table should never be a lazy copy of itself!
-  if (this->lc_slot_table_ == &this->slot_table_)
+  if ( (0 != this->lazy_copy_)
+      && (&this->lazy_copy_->current_slot_table () == &this->slot_table_))
   {
     if (TAO_debug_level > 0)
-      ACE_DEBUG ((LM_DEBUG, ACE_TEXT ("TAO (%P|%t) Lazy copy of self detected at %N,%l")));
+      ACE_DEBUG ((LM_DEBUG, ACE_TEXT ("TAO (%P|%t) Lazy copy of self detected at %N,%l\n")));
     ACE_THROW (CORBA::INTERNAL ());
   }
 
+  // Get the slot table that is currently active
+  PICurrent_Impl::Table & table = this->current_slot_table ();
   CORBA::Any * any = 0;
 
   if (identifier < table.size ())
@@ -99,21 +79,14 @@ TAO::PICurrent_Impl::set_slot (PortableInterceptor::SlotId identifier,
   // No need to check validity of SlotId.  It is validated before this
   // method is invoked.
 
-  // Perform deep copy of the logically copied slot table, if
-  // necessary, before modifying our own slot table. This is a setup
-  // where another PICurrent refers to our slot table, so we force the
-  // the other PICurrent does copy our table before making changes to
-  // our table.
-  if (this->copy_callback_ != 0)
-    this->copy_callback_->execute ();
-
-  // If we have a logical copied slot table we refer to, just make a
-  // copy of that table first before making changes to our table.
-  if (this->lc_slot_table_ != 0)
-    {
-      this->slot_table_ = *this->lc_slot_table_;
-      this->lc_slot_table_ = 0;
-    }
+  // Break any existing ties that another PICurrent has with our table
+  // since our table is changing.
+  if (0 != this->impending_change_callback_)
+    this->impending_change_callback_->convert_from_lazy_to_real_copy ();
+
+  // Ensure that we have a real physical copy of the table before
+  // making any changes to it.
+  this->convert_from_lazy_to_real_copy ();
 
   // If the slot table array isn't large enough, then increase its
   // size.  We're guaranteed not to exceed the number of allocated
@@ -126,16 +99,41 @@ TAO::PICurrent_Impl::set_slot (PortableInterceptor::SlotId identifier,
 }
 
 void
-TAO::PICurrent_Impl::execute_destruction_callback (
-  TAO::PICurrent_Impl::Table * old_lc_slot_table)
+TAO::PICurrent_Impl::take_lazy_copy (
+  TAO::PICurrent_Impl * p)
 {
-  // we are being asked to lc another table, if this
-  // is null, make sure we take a physical copy of the
-  // existing table we had lc before it disappears.
-  if ((0 == old_lc_slot_table) && (0 != this->lc_slot_table_))
-    this->slot_table_ = *this->lc_slot_table_;
-
-  this->lc_slot_table_ = old_lc_slot_table;
+  // Check that we are being told to actually change which table we are
+  // copying from. (If it is the same as before OR it would ultimately be
+  // the same table, we are already correctly setup and we do nothing.)
+  if ( (p != this->lazy_copy_)
+      && ((0 == p) || (&p->current_slot_table () != &this->current_slot_table ()))
+      )
+    {
+      // Break any existing ties that another PICurrent has with our table
+      // since our table is changing.
+      if (0 != this->impending_change_callback_)
+        this->impending_change_callback_->convert_from_lazy_to_real_copy ();
+
+      // If we have previously logically copied another table, ensure it is
+      // told that we are no longer interested in it so that it will not
+      // call our conver_from_lazy_to_real_copy() when it changes/destructs.
+      if (0 != this->lazy_copy_)
+        this->lazy_copy_->set_callback_for_impending_change (0);
+
+      // Are we being asked to copy ourself (or nothing)
+      if ((0 == p) || (this == p))
+        {
+          this->lazy_copy_ = 0; // Use our own physical slot_table_
+        }
+      else
+        {
+          this->lazy_copy_ = p;
+
+          // Must tell the newly copied PICurrent_Impl that we want to
+          // be told when/if it is going to be changed or destroyed.
+          this->lazy_copy_->set_callback_for_impending_change (this);
+        }
+    }
 }
 
 TAO_END_VERSIONED_NAMESPACE_DECL
diff --git a/TAO/tao/PI/PICurrent_Impl.h b/TAO/tao/PI/PICurrent_Impl.h
index b7d624a4c9b..11876b31acb 100644
--- a/TAO/tao/PI/PICurrent_Impl.h
+++ b/TAO/tao/PI/PICurrent_Impl.h
@@ -37,9 +37,6 @@ class TAO_ORB_Core;
 
 namespace TAO
 {
-  class PICurrent_Copy_Callback;
-  class PICurrent_Impl;
-
   /**
    * @class PICurrent_Impl
    *
@@ -53,10 +50,6 @@ namespace TAO
   class TAO_PI_Export PICurrent_Impl
   {
   public:
-
-    /// Typedef for the underyling "slot table."
-    typedef ACE_Array_Base<CORBA::Any> Table;
-
     /// Constructor.
     PICurrent_Impl (void);
 
@@ -77,19 +70,23 @@ namespace TAO
       ACE_THROW_SPEC ((CORBA::SystemException,
                        PortableInterceptor::InvalidSlot));
 
-    /// Set the PICurrent copy callback object responsible for deep
-    /// copying the source PICurrent's slot table.
-    void copy_callback (PICurrent_Copy_Callback *cb);
+    /// Logically/Lazy (shallow) copy the given object's slot table.
+    void take_lazy_copy (PICurrent_Impl *p);
 
-    /// Set the PICurrent destruction callback object that will be
-    /// notified of this object's destruction.
-    void destruction_callback (PICurrent_Impl *p);
+  private:
+    /// Force this object to convert from a logical (referenced)
+    /// copy, to a physical (or deep, actual) copy.
+    void convert_from_lazy_to_real_copy ();
 
-    /// Execute the destruction callback object
-    void execute_destruction_callback (Table *old_lc_slot_table);
+    /// Set the callback PICurrent_Impl object that will be notified
+    /// of this object's impending destruction or change.
+    /// Set to 0 to clear. (NOTE Only handles a SINGLE object at
+    /// at time, does NOT warn previous callback that this has
+    /// been changed.)
+    void set_callback_for_impending_change (PICurrent_Impl *p);
 
-    /// Return a reference to the underlying slot table.
-    Table & slot_table (void);
+    /// Typedef for the underyling "slot table."
+    typedef ACE_Array_Base<CORBA::Any> Table;
 
     /// Return a reference to the slot table currently associated
     /// with this PICurrent_Impl object.
@@ -97,20 +94,7 @@ namespace TAO
      * @return Logically copied slot table if available, otherwise
      *         underlying slot table.
      */
-    Table & current_slot_table (void);
-
-    /// Logically (shallow) copy the given slot table.
-    // returns true if copied, false if it would be self-referencing.
-    bool lc_slot_table (PICurrent_Impl *p);
-
-    /// Return pointer to the logically copied slot table.
-    /**
-     * @return Zero if no logically copied slot table.  Non-zero
-     *         otherwise.
-     */
-    Table *lc_slot_table (void) const;
-
-  private:
+    Table & current_slot_table ();
 
     /// Prevent copying through the copy constructor and the assignment
     /// operator.
@@ -120,27 +104,19 @@ namespace TAO
     //@}
 
   private:
-
     /// Array of CORBA::Anys that is the underlying "slot table."
     Table slot_table_;
 
-    /// Table that was logically copied from a PICurrent in another
+    /// Access to logical copy from a PICurrent_Impl in another
     /// scope, i.e. either the request scope or the thread scope.
-    Table *lc_slot_table_;
-
-    /// Callback object responsible for performing deep copies of a
-    /// PICurrent's slot table. This is the PICurrent that has our slot_table_
-    /// referred as lc_slot_table_. This copy is there to make sure that when
-    /// we want to modify our table, that we can first copy our table to
-    /// the PICurrent that refers to our table so that it has an unique copy
-    /// of the data.
-    PICurrent_Copy_Callback *copy_callback_;
+    PICurrent_Impl *lazy_copy_;
 
     /// PICurrent_Impl object that will be notified of this object's
-    /// destruction. This is the PICurrent that has our slot_table_ as
-    /// lc_slot_table_.
-    PICurrent_Impl *destruction_callback_;
-
+    /// impending destruction or change to its slot_table_. This is
+    /// the PICurrent_Impl that has access to our slot_table_ via its
+    /// lazy_copy_ pointer. As necessary this allows that object's
+    /// convert_from_lazy_to_real_copy() to be called.
+    PICurrent_Impl *impending_change_callback_;
   };
 }
 
diff --git a/TAO/tao/PI/PICurrent_Impl.inl b/TAO/tao/PI/PICurrent_Impl.inl
index 78c5e33cac6..eaedb899d20 100644
--- a/TAO/tao/PI/PICurrent_Impl.inl
+++ b/TAO/tao/PI/PICurrent_Impl.inl
@@ -4,67 +4,58 @@
 
 TAO_BEGIN_VERSIONED_NAMESPACE_DECL
 
-ACE_INLINE void
-TAO::PICurrent_Impl::copy_callback (TAO::PICurrent_Copy_Callback *cb)
-{
-  this->copy_callback_ = cb;
-}
-
-ACE_INLINE void
-TAO::PICurrent_Impl::destruction_callback (TAO::PICurrent_Impl *p)
-{
-  this->destruction_callback_ = p;
-}
-
-ACE_INLINE TAO::PICurrent_Impl::Table &
-TAO::PICurrent_Impl::slot_table (void)
+ACE_INLINE
+TAO::PICurrent_Impl::PICurrent_Impl ()
+  : slot_table_ (),
+    lazy_copy_ (0),
+    impending_change_callback_ (0)
 {
-  return this->slot_table_;
 }
 
-ACE_INLINE TAO::PICurrent_Impl::Table &
-TAO::PICurrent_Impl::current_slot_table (void)
+ACE_INLINE
+TAO::PICurrent_Impl::~PICurrent_Impl ()
 {
-  return
-    this->lc_slot_table_ == 0 ? this->slot_table_ : *this->lc_slot_table_;
+  // Break any existing ties that another PICurrent has with our table
+  // since our table will no longer exist once this destructor completes.
+  if (0 != this->impending_change_callback_)
+    this->impending_change_callback_->convert_from_lazy_to_real_copy ();
+
+  // If we have logically copied another table, ensure it is told about our
+  // demise so that it will not call our non-existant
+  // convert_from_lazy_to_real_copy() when it changes/destructs.
+  if (0 != this->lazy_copy_)
+    this->lazy_copy_->set_callback_for_impending_change (0);
 }
 
-ACE_INLINE bool
-TAO::PICurrent_Impl::lc_slot_table (TAO::PICurrent_Impl *p)
+ACE_INLINE void
+TAO::PICurrent_Impl::convert_from_lazy_to_real_copy ()
 {
-  // Being told to lazy copy some other table?
-  if (p != 0)
+  // Make sure we take a physical copy of the existing logical
+  // copy of the table before it disappears/changes.
+  if (0 != this->lazy_copy_)
     {
-      // Which actual table are we supposed to lazy copy?
-      Table * t = &p->current_slot_table ();
-
-      // Only if we have not already lazy copied this table
-      if (t != this->lc_slot_table_)
-        {
-          // Whould this be a lazy copy of ourselves?
-          if (t == &this->slot_table_)
-            this->lc_slot_table_ = 0; // Already ourself!
-          else
-            {
-              this->lc_slot_table_ = t;
+      this->slot_table_ = this->lazy_copy_->current_slot_table ();
 
-              // Ensure remote table will tell us if it is
-              // going to change or destroy itself.
-              if (this != p)
-                p->destruction_callback (this);
-            }
-        }
+      // Must tell the old copied PICurrent_Impl that we no
+      // longer want to be told when/if it is going to be
+      // changed or destroyed.
+      this->lazy_copy_->set_callback_for_impending_change (0);
+      this->lazy_copy_ = 0;
     }
-  else
-    this->lc_slot_table_ = 0;
+}
 
-  return (0 != this->lc_slot_table_);
+ACE_INLINE void
+TAO::PICurrent_Impl::set_callback_for_impending_change (TAO::PICurrent_Impl *p)
+{
+  this->impending_change_callback_ = (this == p) ? 0 : p;
 }
 
-ACE_INLINE TAO::PICurrent_Impl::Table *
-TAO::PICurrent_Impl::lc_slot_table (void) const
+ACE_INLINE TAO::PICurrent_Impl::Table &
+TAO::PICurrent_Impl::current_slot_table ()
 {
-  return this->lc_slot_table_;
+  return (0 == this->lazy_copy_) ?
+         this->slot_table_ :
+         this->lazy_copy_->current_slot_table ();
 }
 
 TAO_END_VERSIONED_NAMESPACE_DECL