Implement two-phase session insertion

On the first step an uninitialized object is inserted into the cache
as before (this is necessary to handle recursive loading). The second
step is to notify the session that the object has been initialized.
On this second step the session can perform change tracking preparations,
such as make a copy of the object or reset the modification flag.

New test: common/session/custom (implements a custom session that uses
copies to track changes).

1 files changed, 50 insertions, 0 deletions

diff --git a/common/session/custom/session.cxx b/common/session/custom/session.cxx
new file mode 100644
index 0000000..b50493f
--- /dev/null
+++ b/common/session/custom/session.cxx
@@ -0,0 +1,50 @@
+// file      : common/session/custom/session.cxx
+// copyright : Copyright (c) 2009-2012 Code Synthesis Tools CC
+// license   : GNU GPL v2; see accompanying LICENSE file
+
+#include <cassert>
+
+#include "session.hxx"
+
+static session* current_; // Use TLS in multi-threaded applications.
+
+session::
+session ()
+{
+  assert (current_ == 0);
+  current_ = this;
+}
+
+session::
+~session ()
+{
+  assert (current_ == this);
+  current_ = 0;
+}
+
+bool session::
+has_current ()
+{
+  return current_ != 0;
+}
+
+session& session::
+current ()
+{
+  assert (current_ != 0);
+  return *current_;
+}
+
+void session::
+flush (odb::database& db)
+{
+  for (type_map::iterator i (map_.begin ()), e (map_.end ()); i != e; ++i)
+    i->second->flush (db);
+}
+
+void session::
+mark ()
+{
+  for (type_map::iterator i (map_.begin ()), e (map_.end ()); i != e; ++i)
+    i->second->mark ();
+}