Modernize StreamLogger

   - use std::unique_ptr with special deleter to deal with the
     'sometimes' ownership

GaudiMonitor/src/StreamLogger.h

@@ -13,20 +13,27 @@ public:
   StreamLogger(const std::string& file);
   StreamLogger(std::ostream &ost);
   StreamLogger(IMessageSvc*, MSG::Level);
-  //  StreamLogger();
-  ~StreamLogger();
 
-  std::string name() const;
+  std::string name() const { return m_name; }
 
-  void WriteToStream(const std::string& str) { *p_ost << str << std::endl; }
-  void WriteToMsgSvc(const std::string& str) { *p_msgStr << m_level << str
+  void WriteToStream(const std::string& str) { *m_ost << str << std::endl; }
+  void WriteToMsgSvc(const std::string& str) { *m_msgStr << m_level << str
 							 << endmsg; }
 
 
 private:
-  bool m_isMine;
-  std::ostream *p_ost;
-  MsgStream *p_msgStr;
+  struct maybeDelete {
+      bool m_isMine;
+      maybeDelete(bool isMine = false) : m_isMine(isMine) {}
+      maybeDelete& operator=(maybeDelete&& rhs) { m_isMine = rhs.m_isMine; rhs.m_isMine = false; return *this; }
+      maybeDelete& operator=(maybeDelete& rhs) = delete;
+      maybeDelete(maybeDelete&& rhs) { *this = std::move(rhs); }
+      maybeDelete(const maybeDelete& rhs) = delete;
+      template <typename P>
+      void operator()(P* p) { if (m_isMine) delete p; }
+  };
+  std::unique_ptr<std::ostream,maybeDelete> m_ost;
+  std::unique_ptr<MsgStream> m_msgStr;
   MSG::Level m_level;
   std::string m_name;
 };