feat: add a way to print a message at each stop criterion call

eo/src/utils/checkpointing

@@ -27,6 +27,7 @@
 #include "eoParser.h"
 #include "eoState.h"
 #include "eoUpdater.h"
+#include "eoLogMessage.h"
 #include "eoMonitor.h"
 #include "eoFileMonitor.h"
 #include "eoTimedMonitor.h"

eo/src/utils/eoLogMessage.h

@@ -0,0 +1,59 @@
+/*
+(c) Thales group, 2020
+
+    This library is free software; you can redistribute it and/or modify it under
+    the terms of the GNU Lesser General Public License as published by the Free
+    Software Foundation; version 2 of the license.
+
+    This library is distributed in the hope that it will be useful, but WITHOUT ANY
+    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+    PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License along
+    with this library; if not, write to the Free Software Foundation, Inc., 59
+    Temple Place, Suite 330, Boston, MA 02111-1307 USA
+
+Contact: http://eodev.sourceforge.net
+
+Authors:
+     Johann Dréo <johann.dreo@thalesgroup.com>
+*/
+
+#ifndef _eoLogMessage_h
+#define _eoLogMessage_h
+
+#include <string>
+#include "eoUpdater.h"
+#include "eoLogger.h"
+
+/**
+   An updater that print its message when called (usually within an eoCheckPoint)
+
+    @ingroup Utilities
+*/
+class eoLogMessage : public eoUpdater
+{
+public :
+    eoLogMessage(
+            std::string msg,
+            eoLogger& log = eo::log,
+            eo::Levels level = eo::progress
+        ) :
+            _msg(msg),
+            _log(log),
+            _level(level)
+    { }
+
+    virtual void operator()()
+    {
+        _log << _level << _msg << std::endl;
+    }
+
+protected:
+    std::string _msg;
+    eoLogger& _log;
+    eo::Levels _level;
+
+};
+
+#endif

eo/src/utils/eoUpdater.h

@@ -168,5 +168,4 @@ private :
     const std::string extension;
 };
 
-
 #endif