Add connection and connection factory implementations

1 files changed, 154 insertions, 0 deletions

diff --git a/odb/pgsql/connection-factory.hxx b/odb/pgsql/connection-factory.hxx
new file mode 100644
index 0000000..d90b7cb
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+++ b/odb/pgsql/connection-factory.hxx
@@ -0,0 +1,154 @@
+// file      : odb/pgsql/connection-factory.hxx
+// author    : Constantin Michael <constantin@codesynthesis.com>
+// copyright : Copyright (c) 2009-2011 Code Synthesis Tools CC
+// license   : GNU GPL v2; see accompanying LICENSE file
+
+#ifndef ODB_PGSQL_CONNECTION_FACTORY_HXX
+#define ODB_PGSQL_CONNECTION_FACTORY_HXX
+
+#include <odb/pre.hxx>
+
+#include <vector>
+#include <cstddef> // std::size_t
+
+#include <odb/details/mutex.hxx>
+#include <odb/details/condition.hxx>
+#include <odb/details/shared-ptr.hxx>
+
+#include <odb/pgsql/version.hxx>
+#include <odb/pgsql/forward.hxx>
+#include <odb/pgsql/connection.hxx>
+
+#include <odb/pgsql/details/export.hxx>
+
+namespace odb
+{
+  namespace pgsql
+  {
+    class LIBODB_PGSQL_EXPORT connection_factory
+    {
+    public:
+      virtual details::shared_ptr<connection>
+      connect () = 0;
+
+    public:
+      typedef pgsql::database database_type;
+
+      virtual void
+      database (database_type&) = 0;
+
+      virtual
+      ~connection_factory ();
+    };
+
+    class LIBODB_PGSQL_EXPORT new_connection_factory: public connection_factory
+    {
+    public:
+      new_connection_factory ()
+          : db_ (0)
+      {
+      }
+
+      virtual details::shared_ptr<connection>
+      connect ();
+
+      virtual void
+      database (database_type&);
+
+    private:
+      new_connection_factory (const new_connection_factory&);
+      new_connection_factory& operator= (const new_connection_factory&);
+
+    private:
+      database_type* db_;
+    };
+
+    class LIBODB_PGSQL_EXPORT connection_pool_factory:
+      public connection_factory
+    {
+    public:
+      // The max_connections argument specifies the maximum number of
+      // concurrent connections this pool will maintain. If this value
+      // is 0 then the pool will create a new connection every time all
+      // of the existing connections are in use.
+      //
+      // The min_connections argument specifies the minimum number of
+      // connections that should be maintained by the pool. If the
+      // number of connections maintained by the pool exceeds this
+      // number and there are no active waiters for a new connection,
+      // then the pool will release the excess connections. If this
+      // value is 0 then the pool will maintain all the connections
+      // that were ever created.
+      //
+      connection_pool_factory (std::size_t max_connections = 0,
+                               std::size_t min_connections = 0)
+          : max_ (max_connections),
+            min_ (min_connections),
+            in_use_ (0),
+            waiters_ (0),
+            db_ (0),
+            cond_ (mutex_)
+      {
+        // @@ check min_ <= max_
+      }
+
+      virtual details::shared_ptr<connection>
+      connect ();
+
+      virtual void
+      database (database_type&);
+
+      virtual
+      ~connection_pool_factory ();
+
+    private:
+      connection_pool_factory (const connection_pool_factory&);
+      connection_pool_factory& operator= (const connection_pool_factory&);
+
+    private:
+      class pooled_connection: public connection
+      {
+      public:
+        // NULL pool value indicates that the connection is not in use.
+        //
+        pooled_connection (database_type&, connection_pool_factory*);
+
+      private:
+        static bool
+        zero_counter (void*);
+
+      private:
+        friend class connection_pool_factory;
+
+        shared_base::refcount_callback callback_;
+        connection_pool_factory* pool_;
+      };
+
+      friend class pooled_connection;
+      typedef std::vector<details::shared_ptr<pooled_connection> > connections;
+
+    private:
+      // Return true if the connection should be deleted, false otherwise.
+      //
+      bool
+      release (pooled_connection*);
+
+    private:
+      const std::size_t max_;
+      const std::size_t min_;
+
+      std::size_t in_use_;  // Number of connections currently in use.
+      std::size_t waiters_; // Number of threads waiting for a connection.
+
+      database_type* db_;
+      connections connections_;
+
+      details::mutex mutex_;
+      details::condition cond_;
+    };
+  }
+}
+
+#include <odb/post.hxx>
+
+#endif // ODB_PGSQL_CONNECTION_FACTORY_HXX