tdf#62381: Stop using NPAPI plugin when NP_Initialize fails

(...in the Windows-specific code path)

Change-Id: I5984ecd88a12d3f22aecaa685bd552f4235fb13d
(cherry picked from commit 00daa67d)
Reviewed-on: https://gerrit.libreoffice.org/20474Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Michael Stahl <mstahl@redhat.com>
(cherry picked from commit 448fec81)

extensions/source/plugin/base/xplugin.cxx

@@ -548,9 +548,14 @@ void XPlugin_Impl::loadPlugin()
                 return;
 
 #elif defined WNT
-            PluginComm* pComm = new PluginComm_Impl( m_aDescription.Mimetype,
-                                                     m_aDescription.PluginName,
-                                                     (HWND)pEnvData->hWnd );
+            PluginComm* pComm;
+            try {
+                pComm = new PluginComm_Impl(
+                    m_aDescription.Mimetype, m_aDescription.PluginName,
+                    (HWND)pEnvData->hWnd);
+            } catch (PluginComm_Impl::CannotInitializeException &) {
+                return;
+            }
 #endif
 
             setPluginComm( pComm );

extensions/source/plugin/inc/plugin/win/sysplug.hxx

@@ -86,6 +86,8 @@ class PluginComm_Impl :
 
     virtual long        doIt();
 public:
+    struct CannotInitializeException {};
+
                         PluginComm_Impl( const OUString& rMIME, const OUString& rName, HWND hWnd );
     virtual             ~PluginComm_Impl();
 
@@ -114,6 +116,7 @@ public:
     virtual NPError     NPP_SetValue( NPP instance, NPNVariable variable, void *ret_alue );
 
 private:
+    void                shutdown();
     BOOL                retrieveFunction( TCHAR const * pName, void** ppFunc ) const;
 
 private:

extensions/source/plugin/win/sysplug.cxx

@@ -98,11 +98,19 @@ PluginComm_Impl::PluginComm_Impl( const OUString& /*rMIME*/, const OUString& rNa
                 "### version failure!" );
 
     m_eCall = eNP_Initialize;
-    execute();
+    if (execute() != NPERR_NO_ERROR) {
+        shutdown();
+        throw CannotInitializeException();
+    }
 }
 
 
 PluginComm_Impl::~PluginComm_Impl()
+{
+    shutdown();
+}
+
+void PluginComm_Impl::shutdown()
 {
     if (_plDLL)
     {