From dc6a8f069643b5dda0ef1b113a6d3852a83be464 Mon Sep 17 00:00:00 2001
From: Peter Dimov <pdimov@pdimov.com>
Date: Tue, 25 Mar 2008 15:46:40 +0000
Subject: [PATCH] _internal_accept_owner now checks if _owned isn't already
 true.

[SVN r43856]
---
 include/boost/enable_shared_from_this.hpp | 16 ++++++++++++----
 test/esft_regtest.cpp                     | 12 ++++++++++++
 2 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/include/boost/enable_shared_from_this.hpp b/include/boost/enable_shared_from_this.hpp
index f378272..2ead3fd 100644
--- a/include/boost/enable_shared_from_this.hpp
+++ b/include/boost/enable_shared_from_this.hpp
@@ -94,10 +94,18 @@ public:
     void _internal_accept_owner(shared_ptr<U> &owner) const
     {
         init_internal_shared_once();
-        get_deleter<detail::sp_deleter_wrapper>(_internal_shared_this)->set_deleter(owner);
-        owner.reset( _internal_shared_this, owner.get() );
-        _internal_shared_this.reset();
-        _owned = true;
+
+        if( !_owned )
+        {
+            detail::sp_deleter_wrapper * pd = get_deleter<detail::sp_deleter_wrapper>(_internal_shared_this);
+            BOOST_ASSERT( pd != 0 );
+            pd->set_deleter(owner);
+
+            owner.reset( _internal_shared_this, owner.get() );
+            _internal_shared_this.reset();
+
+            _owned = true;
+        }
     }
 };
 
diff --git a/test/esft_regtest.cpp b/test/esft_regtest.cpp
index 8bc8cd6..35f672e 100644
--- a/test/esft_regtest.cpp
+++ b/test/esft_regtest.cpp
@@ -162,11 +162,23 @@ void test3()
     BOOST_TEST( pv.get() == p );
 }
 
+struct null_deleter
+{
+    void operator()( void const* ) const {}
+};
+
+void test4()
+{
+    boost::shared_ptr<V> pv( new V );
+    boost::shared_ptr<V> pv2( pv.get(), null_deleter() );
+}
+
 int main()
 {
     test();
     test2();
     test3();
+    test4();
 
     return boost::report_errors();
 }