ChangeLogTag:Thu Feb 23 18:41:18 UTC 2006 Ossama Othman <ossama_othman at symantec dot com>

3 files changed, 42 insertions, 6 deletions

diff --git a/TAO/ChangeLog b/TAO/ChangeLog
index 76dd34ce2d9..86b6aa25942 100644
--- a/TAO/ChangeLog
+++ b/TAO/ChangeLog
@@ -1,3 +1,16 @@
+Thu Feb 23 18:41:18 UTC 2006  Ossama Othman  <ossama_othman at symantec dot com>
+
+        * tao/Utils/Servant_Var.inl (operator=):
+        * tao/Valuetype/Value_VarOut_T.cpp (operator=):
+
+          Fixed problem where non-copying assignment prematurely decreased
+          reference count on contained object by adding a check for
+          self-assignment.  The canonical copy-and-swap idiom was used to
+          provide a strong exception safety guarantee.  It doesn't require
+          a self-assignment check for copying assignment but it may be
+          needed for non-copying assignment.  Addresses memory access
+          violations.
+
 Thu Feb 23 17:14:25 UTC 2006  Simon McQueen  <sm@prismtech.com>
 
         * tao/GIOP_Message_Lite.cpp:
diff --git a/TAO/tao/Utils/Servant_Var.inl b/TAO/tao/Utils/Servant_Var.inl
index 6396237bc9c..da2ff1d6e95 100644
--- a/TAO/tao/Utils/Servant_Var.inl
+++ b/TAO/tao/Utils/Servant_Var.inl
@@ -64,8 +64,16 @@ template <class T>
 ACE_INLINE typename TAO::Utils::Servant_Var<T> &
 TAO::Utils::Servant_Var<T>::operator= (T * p)
 {
-  TAO::Utils::Servant_Var<T> tmp (p);
-  this->swap (tmp);
+  if (this->ptr_ != p)
+    {
+      // This constructor doesn't increase the reference count so we
+      // we must check for self-assignment.  Otherwise the reference
+      // count would be prematurely decremented upon exiting this
+      // scope.
+      TAO::Utils::Servant_Var<T> tmp (p);
+      this->swap (tmp);
+    }
+
   return *this;
 }
 
@@ -119,8 +127,16 @@ template <class T> template <class Y>
 ACE_INLINE typename TAO::Utils::Servant_Var<T> &
 TAO::Utils::Servant_Var<T>::operator= (Y * p)
 {
-  TAO::Utils::Servant_Var<T> tmp (p);
-  this->swap (tmp);
+  if (this->ptr_ != p)
+    {
+      // This constructor doesn't increase the reference count so we
+      // we must check for self-assignment.  Otherwise the reference
+      // count would be prematurely decremented upon exiting this
+      // scope.
+      TAO::Utils::Servant_Var<T> tmp (p);
+      this->swap (tmp);
+    }
+
   return *this;
 }
 #endif /* ACE_LACKS_MEMBER_TEMPLATES */
diff --git a/TAO/tao/Valuetype/Value_VarOut_T.cpp b/TAO/tao/Valuetype/Value_VarOut_T.cpp
index 49320b51f77..5e5049b099f 100644
--- a/TAO/tao/Valuetype/Value_VarOut_T.cpp
+++ b/TAO/tao/Valuetype/Value_VarOut_T.cpp
@@ -73,8 +73,15 @@ template <typename T>
 TAO_Value_Var_T<T> &
 TAO_Value_Var_T<T>::operator= (T * p)
 {
-  TAO_Value_Var_T<T> tmp (p);
-  std::swap (this->ptr_, tmp.ptr_);
+  if (this->ptr_ != p)
+    {
+      // This constructor doesn't increase the reference count so we
+      // we must check for self-assignment.  Otherwise the reference
+      // count would be prematurely decremented upon exiting this
+      // scope.
+      TAO_Value_Var_T<T> tmp (p);
+      std::swap (this->ptr_, tmp.ptr_);
+    }
 
   return *this;
 }