Moved shared_container_iterator.hpp in iterator directory, modernized code.

shared_container_iterator now uses std::shared_ptr to store the reference
to the container. boost::shared_ptr is still supported and is wrapped
into std::shared_ptr on construction, so there is overhead due to allocation
of std::shared_ptr state. Going forward, std::shared_ptr is expected
to be the primary use case. As a bonus, this eliminates the dependency
on Boost.SmartPtr.

Moved shared_container_iterator.hpp into the iterator directory and left
a forwarding header for backward compatibility.

Author: Lastique

CMakeLists.txt

@@ -22,7 +22,6 @@ target_link_libraries(boost_iterator
         Boost::fusion
         Boost::mpl
         Boost::optional
-        Boost::smart_ptr
         Boost::type_traits
         Boost::utility
 )

build.jam

@@ -14,7 +14,6 @@ constant boost_dependencies :
     /boost/fusion//boost_fusion
     /boost/mpl//boost_mpl
     /boost/optional//boost_optional
-    /boost/smart_ptr//boost_smart_ptr
     /boost/type_traits//boost_type_traits
     /boost/utility//boost_utility ;
 

include/boost/iterator/shared_container_iterator.hpp

@@ -0,0 +1,117 @@
+// (C) Copyright Ronald Garcia 2002. Permission to copy, use, modify, sell and
+// distribute this software is granted provided this copyright notice appears
+// in all copies. This software is provided "as is" without express or implied
+// warranty, and with no claim as to its suitability for any purpose.
+
+// See http://www.boost.org/libs/utility/shared_container_iterator.html for documentation.
+
+#ifndef BOOST_ITERATOR_SHARED_CONTAINER_ITERATOR_HPP_INCLUDED_
+#define BOOST_ITERATOR_SHARED_CONTAINER_ITERATOR_HPP_INCLUDED_
+
+#include <memory>
+#include <utility>
+#include <boost/iterator/iterator_adaptor.hpp>
+
+namespace boost {
+
+// For backward compatibility with boost::shared_ptr
+template< class T >
+class shared_ptr;
+
+namespace iterators {
+namespace detail {
+
+// Fake deleter that holds an instance of boost::shared_ptr and through it keeps the pointed object from deletion
+template< typename T >
+class shared_container_iterator_bsptr_holder
+{
+private:
+    boost::shared_ptr< T > m_ptr;
+
+public:
+    explicit shared_container_iterator_bsptr_holder(boost::shared_ptr< T > const& ptr) :
+        m_ptr(ptr)
+    {}
+
+    void operator()(T*) const noexcept {}
+};
+
+} // namespace detail
+
+template< typename Container >
+class shared_container_iterator :
+    public iterator_adaptor<
+        shared_container_iterator< Container >,
+        typename Container::iterator
+    >
+{
+private:
+    using super_t = iterator_adaptor<
+        shared_container_iterator< Container >,
+        typename Container::iterator
+    >;
+
+    using iterator_t = typename Container::iterator;
+    using container_ref_t = std::shared_ptr< Container >;
+
+public:
+    shared_container_iterator() = default;
+
+    shared_container_iterator(iterator_t const& x, container_ref_t const& c) :
+        super_t(x),
+        m_container_ref(c)
+    {}
+
+    // Constructor for backward compatibility with boost::shared_ptr
+    shared_container_iterator(iterator_t const& x, boost::shared_ptr< Container > const& c) :
+        super_t(x),
+        m_container_ref(c.get(), detail::shared_container_iterator_bsptr_holder< Container >(c))
+    {}
+
+private:
+    container_ref_t m_container_ref;
+};
+
+template< typename Container >
+inline shared_container_iterator< Container >
+make_shared_container_iterator(typename Container::iterator iter, std::shared_ptr< Container > const& container)
+{
+    return shared_container_iterator< Container >(iter, container);
+}
+
+template< typename Container >
+inline std::pair< shared_container_iterator< Container >, shared_container_iterator< Container > >
+make_shared_container_range(std::shared_ptr< Container > const& container)
+{
+    return std::make_pair
+    (
+        iterators::make_shared_container_iterator(container->begin(), container),
+        iterators::make_shared_container_iterator(container->end(), container)
+    );
+}
+
+// Factory functions for backward compatibility with boost::shared_ptr
+template< typename Container >
+inline shared_container_iterator< Container >
+make_shared_container_iterator(typename Container::iterator iter, boost::shared_ptr< Container > const& container)
+{
+    return shared_container_iterator< Container >(iter, container);
+}
+
+template< typename Container >
+inline std::pair< shared_container_iterator< Container >, shared_container_iterator< Container > >
+make_shared_container_range(boost::shared_ptr< Container > const& container)
+{
+    std::shared_ptr< Container > c(container.get(), detail::shared_container_iterator_bsptr_holder< Container >(container));
+    return iterators::make_shared_container_range(std::move(c));
+}
+
+} // namespace iterators
+
+using iterators::shared_container_iterator;
+using iterators::make_shared_container_iterator;
+using iterators::make_shared_container_range;
+
+} // namespace boost
+
+#endif // BOOST_ITERATOR_SHARED_CONTAINER_ITERATOR_HPP_INCLUDED_

include/boost/shared_container_iterator.hpp

@@ -1,69 +1,14 @@
-// (C) Copyright Ronald Garcia 2002. Permission to copy, use, modify, sell and
-// distribute this software is granted provided this copyright notice appears
-// in all copies. This software is provided "as is" without express or implied
-// warranty, and with no claim as to its suitability for any purpose.
-
-// See http://www.boost.org/libs/utility/shared_container_iterator.html for documentation.
+// (C) Copyright Andrey Semashev 2025.
+// Distributed under the Boost Software License, Version 1.0. (See
+// accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
 
 #ifndef BOOST_SHARED_CONTAINER_ITERATOR_HPP
 #define BOOST_SHARED_CONTAINER_ITERATOR_HPP
 
-#include "boost/iterator_adaptors.hpp"
-#include "boost/shared_ptr.hpp"
-#include <utility>
-
-namespace boost {
-namespace iterators {
-
-template <typename Container>
-class shared_container_iterator : public iterator_adaptor<
-                                    shared_container_iterator<Container>,
-                                    typename Container::iterator> {
-
-  typedef iterator_adaptor<
-    shared_container_iterator<Container>,
-    typename Container::iterator> super_t;
-
-  typedef typename Container::iterator iterator_t;
-  typedef boost::shared_ptr<Container> container_ref_t;
-
-  container_ref_t container_ref;
-public:
-  shared_container_iterator() { }
-
-  shared_container_iterator(iterator_t const& x,container_ref_t const& c) :
-    super_t(x), container_ref(c) { }
-
-
-};
-
-template <typename Container>
-inline shared_container_iterator<Container>
-make_shared_container_iterator(typename Container::iterator iter,
-                               boost::shared_ptr<Container> const& container) {
-  typedef shared_container_iterator<Container> iterator;
-  return iterator(iter,container);
-}
-
-
-
-template <typename Container>
-inline std::pair<
-  shared_container_iterator<Container>,
-  shared_container_iterator<Container> >
-make_shared_container_range(boost::shared_ptr<Container> const& container) {
-  return
-    std::make_pair(
-      make_shared_container_iterator(container->begin(),container),
-      make_shared_container_iterator(container->end(),container));
-}
-
-} // namespace iterators
-
-using iterators::shared_container_iterator;
-using iterators::make_shared_container_iterator;
-using iterators::make_shared_container_range;
+// This is a deprecated header left for backward compatibility.
+// Please use <boost/iterator/shared_container_iterator.hpp> instead.
 
-} // namespace boost
+#include <boost/iterator/shared_container_iterator.hpp>
 
-#endif
+#endif // BOOST_SHARED_CONTAINER_ITERATOR_HPP

test/Jamfile.v2

@@ -74,5 +74,5 @@ test-suite iterator
     [ compile adl_test.cpp : <library>/boost/array//boost_array ]
     [ compile range_distance_compat_test.cpp : <library>/boost/range//boost_range ]
 
-    [ run shared_iterator_test.cpp ]
+    [ run shared_iterator_test.cpp : : : <library>/boost/smart_ptr//smart_ptr ]
 ;

test/shared_iterator_test.cpp

@@ -14,33 +14,35 @@
 //
 
 
-#include "boost/shared_container_iterator.hpp"
-#include "boost/shared_ptr.hpp"
+#include <boost/iterator/shared_container_iterator.hpp>
+#include <boost/shared_ptr.hpp>
 #include <boost/core/lightweight_test.hpp>
 #include <vector>
+#include <memory>
 
-struct resource {
+struct resource
+{
   static int count;
   resource() { ++count; }
   resource(resource const&) { ++count; }
   ~resource() { --count; }
 };
 int resource::count = 0;
 
-typedef std::vector<resource> resources_t;
+typedef std::vector< resource > resources_t;
 
 typedef boost::shared_container_iterator< resources_t > iterator;
 
-
-void set_range(iterator& i, iterator& end)  {
-
-  boost::shared_ptr< resources_t > objs(new resources_t());
+template< typename SharedPtr >
+void set_range(iterator& i, iterator& end)
+{
+  SharedPtr objs(new resources_t());
 
   for (int j = 0; j != 6; ++j)
     objs->push_back(resource());
 
-  i = iterator(objs->begin(),objs);
-  end = iterator(objs->end(),objs);
+  i = iterator(objs->begin(), objs);
+  end = iterator(objs->end(), objs);
   BOOST_TEST_EQ(resource::count, 6);
 }
 
@@ -53,7 +55,18 @@ int main() {
     iterator i;
     {
       iterator end;
-      set_range(i,end);
+      set_range< boost::shared_ptr< resources_t > >(i, end);
+      BOOST_TEST_EQ(resource::count, 6);
+    }
+    BOOST_TEST_EQ(resource::count, 6);
+  }
+  BOOST_TEST_EQ(resource::count, 0);
+
+  {
+    iterator i;
+    {
+      iterator end;
+      set_range< std::shared_ptr< resources_t > >(i, end);
       BOOST_TEST_EQ(resource::count, 6);
     }
     BOOST_TEST_EQ(resource::count, 6);

test/test_cmake/main.cpp

@@ -7,7 +7,6 @@
 #include <boost/indirect_reference.hpp>
 #include <boost/next_prior.hpp>
 #include <boost/pointee.hpp>
-#include <boost/shared_container_iterator.hpp>
 #include <boost/iterator/advance.hpp>
 #include <boost/iterator/counting_iterator.hpp>
 #include <boost/iterator/distance.hpp>
@@ -31,6 +30,7 @@
 #include <boost/iterator/new_iterator_tests.hpp>
 #include <boost/iterator/permutation_iterator.hpp>
 #include <boost/iterator/reverse_iterator.hpp>
+#include <boost/iterator/shared_container_iterator.hpp>
 #include <boost/iterator/transform_iterator.hpp>
 #include <boost/iterator/zip_iterator.hpp>