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+// file : odb/qt/containers/list-traits.txx
+// license : GNU GPL v2; see accompanying LICENSE file
+
+namespace odb
+{
+ template <typename V>
+ bool access::container_traits<QOdbList<V> >::
+ changed (const container_type& c)
+ {
+ // Because modifications can cancel each other (e.g., push and pop),
+ // it is tricky to keep track of whether there are any changes in
+ // the container. Instead, we are just going to examine each element
+ // just like update().
+ //
+
+ // We should either be tracking or summarily changed.
+ //
+ if (c._tracking ())
+ {
+ const vector_impl& impl (c._impl ());
+
+ for (std::size_t i (0), n (impl.size ()); i < n; ++i)
+ {
+ if (impl.state (i) != vector_impl::state_unchanged)
+ return true;
+ }
+ }
+ else
+ return true;
+
+ return false;
+ }
+
+ template <typename V>
+ void access::container_traits<QOdbList<V> >::
+ update (const container_type& c, const functions& f)
+ {
+ bool u (false); // Updated flag.
+
+ if (c._tracking ())
+ {
+ const vector_impl& impl (c._impl ());
+
+ for (std::size_t i (0), n (impl.size ()); i < n; ++i)
+ {
+ vector_impl::element_state_type s (impl.state (i));
+ index_type ii (static_cast<index_type> (i));
+
+ switch (s)
+ {
+ case vector_impl::state_unchanged:
+ {
+ break;
+ }
+ case vector_impl::state_inserted:
+ {
+ f.insert (ii, c[ii]);
+ u = u || true;
+ break;
+ }
+ case vector_impl::state_updated:
+ {
+ f.update (ii, c[ii]);
+ u = u || true;
+ break;
+ }
+ case vector_impl::state_erased:
+ {
+ f.delete_ (ii); // Delete from i onwards.
+ u = u || true;
+ break;
+ }
+ }
+
+ // We delete all trailing elements in one go.
+ //
+ if (s == vector_impl::state_erased)
+ break;
+ }
+ }
+ else
+ {
+ // Fall back to delete all/insert all.
+ //
+ f.delete_ (0);
+
+ for (index_type i (0), n (c.size ()); i < n; ++i)
+ f.insert (i, c[i]);
+
+ u = true;
+ }
+
+ // Arm the rollback callback and (re)start change tracking.
+ //
+ if (u)
+ {
+ c._arm (transaction::current ());
+ c._start ();
+ }
+ }
+}