extended interface

mgo.go

@@ -36,8 +36,13 @@ func (c *MgoConnection) Close() {
 }
 
 type MgoSession struct {
-	session *mgo.Session
-	closed  bool
+	connection *MgoConnection
+	session    *mgo.Session
+	closed     bool
+}
+
+func (s *MgoSession) Connection() Connection {
+	return s.connection
 }
 
 func (s *MgoSession) Close() {
@@ -49,7 +54,10 @@ func (s *MgoSession) Close() {
 }
 
 func (c *MgoConnection) NewSession() Session {
-	s := &MgoSession{session: c.connection.Copy()}
+	s := &MgoSession{
+		connection: c,
+		session:    c.connection.Copy(),
+	}
 	runtime.SetFinalizer(s, func(s *MgoSession) {
 		if !s.closed {
 			s.Close()
@@ -68,15 +76,23 @@ func (s *MgoSession) DB(name string) Database {
 }
 
 type MgoCollection struct {
+	database   *MgoDatabase
 	collection *mgo.Collection
 }
 
+func (c *MgoCollection) DB() Database {
+	return c.database
+}
+
 func (db *MgoDatabase) Session() Session {
 	return db.session
 }
 
 func (db *MgoDatabase) C(name string) Collection {
-	return &MgoCollection{collection: db.database.C(name)}
+	return &MgoCollection{
+		database:   db,
+		collection: db.database.C(name),
+	}
 }
 
 func (db *MgoDatabase) Name() string {

types.go

@@ -16,6 +16,7 @@ type Connection interface {
 }
 
 type Session interface {
+	Connection() Connection
 	Close()
 	DB(name string) Database
 }
@@ -36,6 +37,7 @@ type Database interface {
 }
 
 type Collection interface {
+	DB() Database
 	Insert(docs ...interface{}) error
 	UpdateId(id interface{}, update interface{}) error
 	RemoveId(id interface{}) error