Add support for value wrappers

Wrapper is a class that wraps another type. Examples of wrappers are
various smart pointers, holders, etc. A wrapper can be transparent or
it can handle the NULL semantics.

The new odb::nullable class template is a NULL wrapper that helps
to add the NULL semantics to a value type.

New test: common/wrapper.

1 files changed, 53 insertions, 0 deletions

diff --git a/common/wrapper/test.hxx b/common/wrapper/test.hxx
new file mode 100644
index 0000000..68a8750
--- /dev/null
+++ b/common/wrapper/test.hxx
@@ -0,0 +1,53 @@
+// file      : common/wrapper/test.hxx
+// author    : Boris Kolpackov <boris@codesynthesis.com>
+// copyright : Copyright (c) 2009-2011 Code Synthesis Tools CC
+// license   : GNU GPL v2; see accompanying LICENSE file
+
+#ifndef TEST_HXX
+#define TEST_HXX
+
+#include <common/config.hxx> // HAVE_TR1_MEMORY
+
+#include <string>
+#include <memory> // std::auto_ptr
+#include <vector>
+
+#include <odb/core.hxx>
+#include <odb/nullable.hxx>
+
+#ifdef HAVE_TR1_MEMORY
+#  include <odb/tr1/memory.hxx>
+#endif
+
+using odb::nullable;
+
+typedef nullable<std::string> nullable_string;
+
+#ifdef HAVE_TR1_MEMORY
+typedef std::tr1::shared_ptr<std::string> tr1_nullable_string;
+#endif
+
+#pragma db object
+struct object
+{
+  #pragma db id auto
+  unsigned long id_;
+
+  std::auto_ptr<unsigned long> num;
+
+  #pragma db null
+  std::auto_ptr<std::string> str;
+
+  nullable_string nstr;
+  std::vector<nullable_string> nstrs;
+
+#ifdef HAVE_TR1_MEMORY
+  #pragma db null
+  tr1_nullable_string tr1_str;
+
+  #pragma db value_null
+  std::vector<tr1_nullable_string> tr1_strs;
+#endif
+};
+
+#endif // TEST_HXX