1 files changed, 42 insertions, 0 deletions
diff --git a/sql/sql_callback.h b/sql/sql_callback.h
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+++ b/sql/sql_callback.h
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+/*
+  Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
+
+  This program is free software; you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation; version 2 of the License.
+
+  This program 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 General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program; if not, write to the Free Software
+  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335  USA
+*/
+
+#ifndef SQL_CALLBACK_INCLUDED
+#define SQL_CALLBACK_INCLUDED
+
+/**
+   Macro used for an internal callback.
+
+   The macro will check that the object exists and that the function
+   is defined. If that is the case, it will call the function with the
+   given parameters.
+
+   If the object or the function is not defined, the callback will be
+   considered successful (nothing needed to be done) and will
+   therefore return no error.
+ */
+
+#define MYSQL_CALLBACK(OBJ, FUNC, PARAMS)         \
+  do {                                            \
+    if ((OBJ) && ((OBJ)->FUNC))                   \
+      (OBJ)->FUNC PARAMS;                         \
+  } while (0)
+
+#define MYSQL_CALLBACK_ELSE(OBJ, FUNC, PARAMS, ELSE)    \
+  (((OBJ) && ((OBJ)->FUNC)) ? (OBJ)->FUNC PARAMS : (ELSE))
+
+#endif /* SQL_CALLBACK_INCLUDED */