Namespace management for static multi-database support

Now in libodb the odb::core namespace is split into odb::common (database-
independent stuff) and odb::core proper, which imports odb::common. Each
database runtime now defines odb::<db>::core namespace which also imports
odb::common and adds the database-specific bits. The overall idea is that
one can do using namespace odb::<db>::core just like for odb::core.

1 files changed, 19 insertions, 2 deletions

diff --git a/odb/forward.hxx b/odb/forward.hxx
index 705acd3..fe23c5f 100644
--- a/odb/forward.hxx
+++ b/odb/forward.hxx
@@ -14,6 +14,19 @@
 
 namespace odb
 {
+  // Common and core namespaces. The idea is that you can use the
+  // using directive to get database-independent (common) names or
+  // all core names (core).
+  //
+  namespace common {}
+
+  namespace core
+  {
+    using namespace common;
+  }
+
+  //
+  //
   class database;
   class connection;
   typedef details::shared_ptr<connection> connection_ptr;
@@ -21,6 +34,11 @@ namespace odb
   class statement;
   class session;
 
+  namespace common
+  {
+    using odb::session;
+  }
+
   namespace core
   {
     using odb::database;
@@ -28,7 +46,6 @@ namespace odb
     using odb::connection_ptr;
     using odb::transaction;
     using odb::statement;
-    using odb::session;
   }
 
   // Tracing.
@@ -36,7 +53,7 @@ namespace odb
   class tracer; // Not in core.
   extern LIBODB_EXPORT tracer& stderr_tracer;
 
-  namespace core
+  namespace common
   {
     using odb::stderr_tracer;
   }