ConnectSE: fixing memory leaks reported by valgrind

storage/connect/libdoc.cpp

@@ -8,6 +8,9 @@
 #include <libxml/tree.h>
 #include <libxml/xpath.h>
 #include <libxml/xpathInternals.h>
+#include <libxml/catalog.h>
+#include <libxml/xmlschemastypes.h>
+#include <libxml/relaxng.h>
 //#if defined(WIN32)
 //#include <windows.h>
 //#else   // !WIN32
@@ -290,10 +293,46 @@ if (!rc)
 /******************************************************************/
 /*  XML library cleanup function.                                 */
 /******************************************************************/
+/*
+  This is a copy of xmlCleanupParser() from the libxml2 sources
+  with xmlResetLastError() commented.
+
+  xmlResetLastError() called from the original xmlCleanupParser() causes
+  valgrind to report memory leaks. This happens because
+  ha_initialize_handlerton() is called from the main thread in mysqld.cc,
+  while ha_finalize_handlerton() is called from a non-main thread.
+  libxml2 gets confused because of xmlInitParser() and xmlCleanupParser()
+  being called from the different threads.
+
+  Perhaps the code in mysqld.cc should eventually be modified
+  to shutdown plugins from the main thread.
+*/
+static void
+xmlCleanupParser_replacement(void)
+  {
+  xmlCleanupCharEncodingHandlers();
+#ifdef LIBXML_CATALOG_ENABLED
+  xmlCatalogCleanup();
+#endif
+  xmlDictCleanup();
+  xmlCleanupInputCallbacks();
+#ifdef LIBXML_OUTPUT_ENABLED   
+  xmlCleanupOutputCallbacks();
+#endif
+#ifdef LIBXML_SCHEMAS_ENABLED
+  xmlSchemaCleanupTypes(); 
+  xmlRelaxNGCleanupTypes();
+#endif
+  //xmlResetLastError();
+  xmlCleanupGlobals();
+  xmlCleanupThreads(); /* must be last if called not from the main thread */
+  xmlCleanupMemory();
+  }
+
+
 void XmlCleanupParserLib(void)
   {
-  xmlCleanupParser();
-  xmlMemoryDump();
+  xmlCleanupParser_replacement();
   } // end of XmlCleanupParserLib
 
 /******************************************************************/