Delay creating surfaces with the SurfaceManager plugin until it's needed

DDRec/include/DDRec/SurfaceManager.h

@@ -41,17 +41,13 @@ namespace dd4hep {
       SurfaceManager(const Detector& theDetector);
 
       /// No default constructor
-#if defined(G__ROOT)
-      SurfaceManager() = default ;
-#else
       SurfaceManager() = delete ;
-#endif
 
       ~SurfaceManager() = default;
       SurfaceManager(const SurfaceManager&) = delete;
       SurfaceManager& operator=(const SurfaceManager&) = delete;
-      SurfaceManager(SurfaceManager&&) = default;
-      SurfaceManager& operator=(SurfaceManager&&) = default;
+      SurfaceManager(SurfaceManager&&) = delete;
+      SurfaceManager& operator=(SurfaceManager&&) = delete;
 
 
       /** Get the maps of all surfaces associated to the given detector or
@@ -68,9 +64,11 @@ namespace dd4hep {
 
 
       /// initialize all known surface maps
-      void initialize(const Detector& theDetector) ;
+      void initialize(const Detector& theDetector) const;
 
-      SurfaceMapsMap _map ;
+      mutable SurfaceMapsMap  _map{} ;
+      const Detector& _theDetector ;
+      mutable std::once_flag  _initializedFlag{} ;
     };
 
   } /* namespace rec */

DDRec/src/SurfaceManager.cpp

@@ -15,25 +15,27 @@
 #include "DDRec/SurfaceHelper.h"
 #include "DD4hep/VolumeManager.h"
 #include "DD4hep/Detector.h"
+#include "DD4hep/Printout.h"
 
 #include <sstream>
 
 namespace dd4hep {
   namespace rec {
 
-    SurfaceManager::SurfaceManager(const Detector& theDetector){
+    SurfaceManager::SurfaceManager(const Detector& theDetector) : _theDetector(theDetector) {
 
       // have to make sure the volume manager is populated once in order to have
       // the volumeIDs attached to the DetElements
 
       VolumeManager::getVolumeManager(theDetector);
 
-      initialize(theDetector) ;
     }
 
 
     const SurfaceMap* SurfaceManager::map( const std::string& name ) const {
 
+      std::call_once( _initializedFlag, &SurfaceManager::initialize, this, _theDetector ) ;
+
       SurfaceMapsMap::const_iterator it = _map.find( name ) ;
 
       if( it != _map.end() ){
@@ -44,7 +46,7 @@ namespace dd4hep {
       return nullptr ;
     }
 
-    void SurfaceManager::initialize(const Detector& description) {
+    void SurfaceManager::initialize(const Detector& description) const {
 
       for(const auto& type : description.detectorTypes()) {
 
@@ -75,6 +77,8 @@ namespace dd4hep {
         }
       }
 
+      printout(INFO,"SurfaceManager","%s" , description.extension<SurfaceManager>()->toString().c_str() );
+
     }
 
     std::string SurfaceManager::toString() const {

DDRec/src/plugins/createSurfaceManager.cpp

@@ -40,10 +40,10 @@ namespace dd4hep{
     static long createSurfaceManager(Detector& description, int /*argc*/, char** /*argv*/) {
 
       printout(INFO,"InstallSurfaceManager","**** running plugin InstallSurfaceManager ! " );
+      printout(INFO,"InstallSurfaceManager","**** the map of surfaces will be created on first access ! " );
 
       description.addExtension<SurfaceManager>(  new SurfaceManager(description) ) ;
 
-      printout(INFO,"InstallSurfaceManager","%s" , description.extension<SurfaceManager>()->toString().c_str() );
 
       return 1;
     }