Added a new plugin loader

GeoModelKernel/GeoModelKernel/GeoGeometryPluginLoader.h

+/*
+  Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
+*/
+
+#ifndef GEOGEOMETRYPLUGINLOADER_H_
+#define GEOGEOMETRYPLUGINLOADER_H_
+#include <string> 
+class GeoVGeometryPlugin;
+class GeoGeometryPluginLoader 
+{
+ public:
+
+  // Constructor:
+  GeoGeometryPluginLoader();
+
+  // Destructor:
+  ~GeoGeometryPluginLoader();
+
+  // load Geometry plugin
+  GeoVGeometryPlugin *load(const std::string & path) const;
+  
+ private:
+  
+  GeoGeometryPluginLoader(const GeoGeometryPluginLoader &)=delete;
+  GeoGeometryPluginLoader & operator=(const GeoGeometryPluginLoader &)=delete;
+
+};
+
+#endif

GeoModelKernel/src/GeoGeometryPluginLoader.cxx

+#include "GeoModelKernel/GeoGeometryPluginLoader.h"
+#include "GeoModelKernel/GeoVGeometryPlugin.h"
+#include <string>
+#include <iostream>
+#include <dlfcn.h>
+#include <libgen.h>
+
+GeoGeometryPluginLoader::GeoGeometryPluginLoader () {
+}
+
+GeoGeometryPluginLoader::~GeoGeometryPluginLoader () {
+}
+
+
+GeoVGeometryPlugin *GeoGeometryPluginLoader::load(const std::string & pString) const {
+  std::string bNameString=basename ((char *) pString.c_str());       // Strip off the directory
+  bNameString=bNameString.substr(3);                        // Strip off leading "lib"
+  bNameString=bNameString.substr(0,bNameString.find("."));  // Strip off extensions
+  
+  std::string createFunctionName = std::string("create")+bNameString;
+  
+  //
+  // Loads the library:
+  //
+  void *handle = dlopen(pString.c_str(),RTLD_NOW);
+  if (!handle) {
+    std::cerr << dlerror() << std::endl;
+    return nullptr;
+  }
+  
+  //
+  // Gets the function
+  //
+  void *f = dlsym(handle,createFunctionName.c_str());
+  if (!f) {
+    std::cerr << dlerror() << std::endl;
+    return nullptr;
+  }
+  
+  typedef void * (*CreationMethod) ();
+  CreationMethod F = (CreationMethod) f;
+  
+  //
+  // 
+  //
+  GeoVGeometryPlugin * factory = (GeoVGeometryPlugin *) F();
+  return factory;
+
+}