wl#9503: mysql string functionalities as a service for

         mysql_server component (sub-worklog for wl6667)

HLS:
===
What is the problem ?

MySQL has a platform independent character set implementation. To minimize
string conversions all strings in the server core have a character set attached
to them that's carried along as further as possible. This is done through a
special C++ class (String). Components may need to manipulate some of these
String instances. But due to the fact that C++ classes don't travel well across
heap boundaries (dll/exe etc) we need a C API for these class instances.

Why only this much ?

The full API for that would be very large. So this worklog implements only the
minimum subset that the password validation component (and plugin) needs.

How ?

We take the existing composite plugin service (a wrapper around String methods)
and break it up into multiple logically separate component services. This is a
typical example for how re-engineering of existing plugin APIs into service APIs
should go.

Author: V S Murthy Sidagam

components/example/CMakeLists.txt

@@ -1,4 +1,4 @@
-# Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
+# Copyright (c) 2016, 2017, 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
@@ -33,3 +33,15 @@ MYSQL_ADD_COMPONENT(example_component3
   example_component3.cc
   example_math_wrapping_imp.cc
   TEST MODULE)
+
+MYSQL_ADD_COMPONENT(test_string_service
+  test_string_service.cc
+  TEST MODULE)
+
+MYSQL_ADD_COMPONENT(test_string_service_long
+  test_string_service_long.cc
+  TEST MODULE)
+
+MYSQL_ADD_COMPONENT(test_string_service_charset
+  test_string_service_charset.cc
+  TEST MODULE)