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authorBoris Kolpackov <boris@codesynthesis.com>2012-04-23 16:48:01 +0200
committerBoris Kolpackov <boris@codesynthesis.com>2012-04-23 16:48:01 +0200
commit851cbe3927b987ec992bbbb69bd62224bf4a0dc3 (patch)
tree278298c656c75b1625e9408a15e81736c35c194e /odb/sqlite/polymorphic-object-result.txx
parent7d52205f2b2fc9403b9ea46483e8a17746c6be35 (diff)
Polymorphic inheritance support
Diffstat (limited to 'odb/sqlite/polymorphic-object-result.txx')
-rw-r--r--odb/sqlite/polymorphic-object-result.txx266
1 files changed, 266 insertions, 0 deletions
diff --git a/odb/sqlite/polymorphic-object-result.txx b/odb/sqlite/polymorphic-object-result.txx
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+// file : odb/sqlite/polymorphic-object-result.txx
+// copyright : Copyright (c) 2009-2012 Code Synthesis Tools CC
+// license : GNU GPL v2; see accompanying LICENSE file
+
+#include <cassert>
+
+#include <odb/callback.hxx>
+#include <odb/cache-traits.hxx>
+#include <odb/exceptions.hxx> // result_not_cached
+
+#include <odb/sqlite/polymorphic-object-statements.hxx>
+
+namespace odb
+{
+ namespace sqlite
+ {
+ template <typename T>
+ polymorphic_object_result_impl<T>::
+ ~polymorphic_object_result_impl ()
+ {
+ if (!this->end_)
+ statement_->free_result ();
+ }
+
+ template <typename T>
+ polymorphic_object_result_impl<T>::
+ polymorphic_object_result_impl (const query& q,
+ details::shared_ptr<select_statement> st,
+ statements_type& sts)
+ : base_type (sts.connection ().database ()),
+ result_impl_base (q, st),
+ statements_ (sts)
+ {
+ }
+
+ template <typename T>
+ void polymorphic_object_result_impl<T>::
+ load (object_type* pobj, bool fetch)
+ {
+ if (fetch)
+ load_image ();
+
+ 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 ());
+ typename object_traits::image_type& i (statements_.image ());
+ typename root_traits::image_type& ri (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));
+ discriminator_type disc (d);
+
+ // 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);
+
+ // 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 ()
+ {
+ load_image ();
+ return root_traits::id (statements_.root_statements ().image ());
+ }
+
+ template <typename T>
+ typename polymorphic_object_result_impl<T>::discriminator_type
+ polymorphic_object_result_impl<T>::
+ load_discriminator ()
+ {
+ load_image ();
+ return root_traits::discriminator (
+ statements_.root_statements ().image ());
+ }
+
+ template <typename T>
+ void polymorphic_object_result_impl<T>::
+ next ()
+ {
+ this->current (pointer_type ());
+
+ if (!statement_->next ())
+ {
+ statement_->free_result ();
+ this->end_ = true;
+ }
+ }
+
+ template <typename T, typename R>
+ struct polymorphic_image_rebind
+ {
+ // Derived type version.
+ //
+ typedef object_traits<T> traits;
+
+ static bool
+ 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 ());
+ return true;
+ }
+
+ return false;
+ }
+ };
+
+ template <typename R>
+ struct polymorphic_image_rebind<R, R>
+ {
+ // Root type version.
+ //
+ typedef object_traits<R> traits;
+
+ static bool
+ 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++;
+ return true;
+ }
+
+ return false;
+ }
+ };
+
+ template <typename T>
+ void polymorphic_object_result_impl<T>::
+ load_image ()
+ {
+ typedef polymorphic_image_rebind<object_type, root_type> image_rebind;
+
+ // The image can grow between calls to load() as a result of other
+ // statements execution.
+ //
+ image_rebind::rebind (statements_);
+
+ select_statement::result r (statement_->load ());
+
+ if (r == select_statement::truncated)
+ {
+ typename object_traits::image_type& im (statements_.image ());
+
+ if (object_traits::grow (im, statements_.select_image_truncated ()))
+ im.version++;
+
+ if (image_rebind::rebind (statements_))
+ statement_->reload ();
+ }
+ }
+
+ 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 ();
+ }
+ }
+}