feat: determine detector checksum on geometry read (if supported)

Author: wdconinc

CMakeLists.txt

@@ -194,7 +194,7 @@ if(EDM4EIC_INTERFACE_COMPILE_DEFINITIONS)
 endif()
 
 # DD4Hep is required for the most of the part
-find_package(DD4hep REQUIRED)
+find_package(DD4hep 1.26 REQUIRED)
 
 # ACTS cmake-lint: disable=C0103
 find_package(Acts REQUIRED COMPONENTS Core PluginDD4hep PluginJson)

cmake/jana_plugin.cmake

@@ -248,10 +248,10 @@ endmacro()
 macro(plugin_add_dd4hep _name)
 
   if(NOT DD4hep_FOUND)
-    find_package(DD4hep REQUIRED)
+    find_package(DD4hep 1.26 REQUIRED)
   endif()
 
-  plugin_link_libraries(${_name} DD4hep::DDCore DD4hep::DDRec)
+  plugin_link_libraries(${_name} DD4hep::DDCore DD4hep::DDRec ${ARGN})
 
 endmacro()
 

src/services/geometry/dd4hep/DD4hep_service.cc

@@ -17,6 +17,10 @@
 #include <utility>
 #include <vector>
 
+#if __has_include(<DD4hep/plugins/DetectorChecksum.h>)
+#include <DD4hep/plugins/DetectorChecksum.h>
+#endif
+
 #include "DD4hep_service.h"
 #include "services/log/Log_service.h"
 
@@ -139,6 +143,21 @@ void DD4hep_service::Initialize() {
         detector->volumeManager();
         detector->apply("DD4hepVolumeManager", 0, nullptr);
         m_cellid_converter = std::make_unique<const dd4hep::rec::CellIDPositionConverter>(*detector);
+
+        // Determine detector checksum
+        #if __has_include(<DD4hep/plugins/DetectorChecksum.h>)
+        using dd4hep::detail::DetectorChecksum;
+        DetectorChecksum checksum(*detector);
+        checksum.precision = 3;
+        checksum.hash_meshes  = true;
+        checksum.hash_readout = true;
+        checksum.analyzeDetector(detector->world());
+        DetectorChecksum::hashes_t hash_vec{checksum.handleHeader().hash};
+        checksum.checksumDetElement(0, detector->world(), hash_vec, true);
+        DetectorChecksum::hash_t hash = dd4hep::detail::hash64(&hash_vec[0], hash_vec.size() * sizeof(DetectorChecksum::hash_t));
+        m_log->info("Geometry checksum 0x%016lx", hash);
+        #endif
+
         m_dd4hepGeo = std::move(detector); // const
 
         m_log->info("Geometry successfully loaded.");