Polymorphic inheritance support

1 files changed, 304 insertions, 0 deletions

diff --git a/odb/mssql/polymorphic-object-result.txx b/odb/mssql/polymorphic-object-result.txx
new file mode 100644
index 0000000..be4a6ab
--- /dev/null
+++ b/odb/mssql/polymorphic-object-result.txx
@@ -0,0 +1,304 @@
+// file      : odb/mssql/polymorphic-object-result.txx
+// copyright : Copyright (c) 2009-2012 Code Synthesis Tools CC
+// license   : ODB NCUEL; see accompanying LICENSE file
+
+#include <cassert>
+
+#include <odb/callback.hxx>
+#include <odb/cache-traits.hxx>
+#include <odb/exceptions.hxx> // result_not_cached
+
+#include <odb/mssql/exceptions.hxx> // long_data_reload
+#include <odb/mssql/polymorphic-object-statements.hxx>
+
+namespace odb
+{
+  namespace mssql
+  {
+    template <typename T>
+    polymorphic_object_result_impl<T>::
+    ~polymorphic_object_result_impl ()
+    {
+      change_callback_type& cc (
+        statements_.root_statements ().image ().change_callback_);
+
+      if (cc.context == this)
+      {
+        cc.context = 0;
+        cc.callback = 0;
+      }
+
+      if (image_copy_ != 0)
+        object_traits::free_image (image_copy_);
+
+      if (!this->end_)
+        statement_->free_result ();
+    }
+
+    template <typename T>
+    polymorphic_object_result_impl<T>::
+    polymorphic_object_result_impl (const query&,
+                                    details::shared_ptr<select_statement> st,
+                                    statements_type& sts)
+        : base_type (sts.connection ().database ()),
+          statement_ (st),
+          statements_ (sts),
+          use_copy_ (false),
+          image_copy_ (0)
+    {
+    }
+
+    template <typename T>
+    void polymorphic_object_result_impl<T>::
+    load (object_type* pobj, bool)
+    {
+      if (!can_load_)
+        throw long_data_reload ();
+
+      typename statements_type::root_statements_type& rsts (
+        statements_.root_statements ());
+
+      // This is a top-level call so the statements cannot be locked.
+      //
+      assert (!rsts.locked ());
+      typename statements_type::auto_lock l (rsts);
+
+      odb::database& db (this->database ());
+      image_type& i (use_copy_ ? *image_copy_ : statements_.image ());
+      typename root_traits::image_type& ri (
+        use_copy_ ? object_traits::root_image (i) : rsts.image ());
+
+      id_type id (root_traits::id (ri));
+
+      // Determine this object's dynamic type.
+      //
+      typedef typename root_traits::info_type info_type;
+      discriminator_type d (root_traits::discriminator (ri));
+
+      // Use the polymorphic_info() helper to get concrete_info if
+      // object_type is concrete and NULL if it is abstract.
+      //
+      const info_type* spi (polymorphic_info (object_traits::info));
+      const info_type& pi (
+        spi != 0 && spi->discriminator == d
+        ? *spi
+        : root_traits::map->find (d));
+
+      typedef typename root_traits::pointer_type root_pointer_type;
+      typedef typename root_traits::pointer_traits root_pointer_traits;
+
+      typename object_traits::pointer_cache_traits::insert_guard ig;
+
+      if (pobj == 0)
+      {
+        // Need to create a new instance of the dynamic type.
+        //
+        root_pointer_type rp (pi.create ());
+        pointer_type p (
+          root_pointer_traits::template static_pointer_cast<object_type> (rp));
+
+        // Insert it as a root pointer (for non-unique pointers, rp should
+        // still be valid and for unique pointers this is a no-op).
+        //
+        ig.reset (object_traits::pointer_cache_traits::insert (db, id, rp));
+
+        pobj = &pointer_traits::get_ref (p);
+        current (p);
+      }
+      else
+      {
+        // We are loading into an existing instance. If the static and
+        // dynamic types differ, then make sure the instance is at least
+        // of the dynamic type.
+        //
+        if (&pi != &object_traits::info)
+        {
+          const info_type& dpi (root_traits::map->find (typeid (*pobj)));
+
+          if (&dpi != &pi && dpi.derived (pi))
+            throw object_not_persistent (); // @@ type_mismatch ?
+        }
+      }
+
+      callback_event ce (callback_event::pre_load);
+      pi.dispatch (info_type::call_callback, db, pobj, &ce);
+
+      object_traits::init (*pobj, i, &db);
+
+      // If we are using a copy, make sure the callback information for
+      // long data also comes from the copy.
+      //
+      can_load_ = !statement_->stream_result (
+        use_copy_ ? &statements_.image () : 0,
+        use_copy_ ? image_copy_ : 0);
+
+      // Initialize the id image and binding and load the rest of the object
+      // (containers, dynamic part, etc).
+      //
+      typename object_traits::id_image_type& idi (statements_.id_image ());
+      root_traits::init (idi, id);
+
+      binding& idb (statements_.id_image_binding ());
+      if (idi.version != statements_.id_image_version () || idb.version == 0)
+      {
+        object_traits::bind (idb.bind, idi);
+        statements_.id_image_version (idi.version);
+        idb.version++;
+      }
+
+      object_traits::load_ (statements_, *pobj);
+
+      // Load the dynamic part of the object unless static and dynamic
+      // types are the same.
+      //
+      if (&pi != &object_traits::info)
+      {
+        std::size_t d (object_traits::depth);
+        pi.dispatch (info_type::call_load, db, pobj, &d);
+      };
+
+      rsts.load_delayed ();
+      l.unlock ();
+
+      ce = callback_event::post_load;
+      pi.dispatch (info_type::call_callback, db, pobj, &ce);
+      ig.release ();
+    }
+
+    template <typename T>
+    typename polymorphic_object_result_impl<T>::id_type
+    polymorphic_object_result_impl<T>::
+    load_id ()
+    {
+      typename root_traits::image_type& i (
+        use_copy_
+        ? object_traits::root_image (*image_copy_)
+        : statements_.root_statements ().image ());
+
+      return root_traits::id (i);
+    }
+
+    template <typename T>
+    typename polymorphic_object_result_impl<T>::discriminator_type
+    polymorphic_object_result_impl<T>::
+    load_discriminator ()
+    {
+      typename root_traits::image_type& i (
+        use_copy_
+        ? object_traits::root_image (*image_copy_)
+        : statements_.root_statements ().image ());
+
+      return root_traits::discriminator (i);
+    }
+
+    template <typename T, typename R>
+    struct polymorphic_image_rebind
+    {
+      // Derived type version.
+      //
+      typedef object_traits<T> traits;
+
+      static void
+      rebind (typename traits::statements_type& sts)
+      {
+        typename traits::image_type& im (sts.image ());
+
+        if (traits::check_version (sts.select_image_versions (), im))
+        {
+          binding& b (sts.select_image_binding (traits::depth));
+          traits::bind (b.bind, 0, 0, im, statement_select);
+          traits::update_version (
+            sts.select_image_versions (), im, sts.select_image_bindings ());
+        }
+      }
+    };
+
+    template <typename R>
+    struct polymorphic_image_rebind<R, R>
+    {
+      // Root type version.
+      //
+      typedef object_traits<R> traits;
+
+      static void
+      rebind (typename traits::statements_type& sts)
+      {
+        typename traits::image_type& im (sts.image ());
+
+        if (im.version != sts.select_image_version ())
+        {
+          binding& b (sts.select_image_binding ());
+          traits::bind (b.bind, im, statement_select);
+          sts.select_image_version (im.version);
+          b.version++;
+        }
+      }
+    };
+
+    template <typename T>
+    void polymorphic_object_result_impl<T>::
+    next ()
+    {
+      can_load_ = true;
+      this->current (pointer_type ());
+
+      change_callback_type& cc (
+        statements_.root_statements ().image ().change_callback_);
+
+      if (cc.context == this)
+      {
+        cc.callback = 0;
+        cc.context = 0;
+      }
+
+      use_copy_ = false;
+      polymorphic_image_rebind<object_type, root_type>::rebind (statements_);
+
+      if (statement_->fetch () == select_statement::no_data)
+      {
+        statement_->free_result ();
+        this->end_ = true;
+      }
+      else
+      {
+        cc.callback = &change_callback;
+        cc.context = this;
+      }
+    }
+
+    template <typename T>
+    void polymorphic_object_result_impl<T>::
+    cache ()
+    {
+    }
+
+    template <typename T>
+    std::size_t polymorphic_object_result_impl<T>::
+    size ()
+    {
+      throw result_not_cached ();
+    }
+
+    template <typename T>
+    void polymorphic_object_result_impl<T>::
+    change_callback (void* c)
+    {
+      polymorphic_object_result_impl<T>* r (
+        static_cast<polymorphic_object_result_impl<T>*> (c));
+      image_type& im (r->statements_.image ());
+
+      if (r->image_copy_ == 0)
+        r->image_copy_ = object_traits::clone_image (im);
+      else
+        object_traits::copy_image (*r->image_copy_, im);
+
+      typename root_traits::image_type& rim (
+        r->statements_.root_statements ().image ());
+
+      rim.change_callback_.callback = 0;
+      rim.change_callback_.context = 0;
+
+      r->use_copy_ = true;
+    }
+  }
+}