Custom member streamer for CalArray<o2::tpc::PadFlags>::mData

DataFormats/Detectors/TPC/CMakeLists.txt

@@ -40,7 +40,6 @@ o2_add_library(
 
 o2_target_root_dictionary(
   DataFormatsTPC
-  EXTRA_PATCH src/VectorPadflagsCustomStreamer.cxx
   HEADERS include/DataFormatsTPC/ClusterGroupAttribute.h
           include/DataFormatsTPC/ClusterNative.h
           include/DataFormatsTPC/ClusterNativeHelper.h

DataFormats/Detectors/TPC/src/DataFormatsTPCLinkDef.h

@@ -22,15 +22,15 @@
 #pragma link C++ class o2::tpc::ClusterHardwareContainerFixedSize < 8192> + ;
 #pragma link C++ class o2::tpc::ClusterNativeContainer + ;
 #pragma link C++ class o2::tpc::Digit + ;
-// pragma link C++ enum o2::tpc::PadFlags +;                // enum itself
+#pragma link C++ enum o2::tpc::PadFlags + ; // enum itself
 #pragma link C++ class o2::tpc::ZeroSuppressedContainer8kb + ;
 #pragma link C++ class std::vector < o2::tpc::ClusterNative> + ;
 #pragma link C++ class std::vector < o2::tpc::ClusterNativeContainer> + ;
 #pragma link C++ class std::vector < o2::tpc::ClusterHardware> + ;
 #pragma link C++ class std::vector < o2::tpc::ClusterHardwareContainerFixedSize < 8192>> + ;
 #pragma link C++ class std::vector < o2::tpc::ClusterHardwareContainer8kb> + ;
 #pragma link C++ class std::vector < o2::tpc::Digit> + ;
-// pragma link C++ class std::vector < o2::tpc::PadFlags> + ;
+#pragma link C++ class std::vector < o2::tpc::PadFlags> + ;
 #pragma link C++ class std::vector < o2::tpc::ZeroSuppressedContainer8kb> + ;
 #pragma link C++ class o2::tpc::TrackTPC + ;
 #pragma link C++ class o2::tpc::LaserTrack + ;

Detectors/TPC/base/CMakeLists.txt

@@ -43,6 +43,7 @@ o2_add_library(TPCBase
                                      O2::DetectorsRaw O2::CCDB FairRoot::Base)
 
 o2_target_root_dictionary(TPCBase
+                          EXTRA_PATCH src/TPCFlagsMemberCustomStreamer.cxx
                           HEADERS include/TPCBase/CalArray.h
                                   include/TPCBase/CalDet.h
                                   include/TPCBase/CDBInterface.h

Detectors/TPC/base/src/TPCBaseLinkDef.h

@@ -21,6 +21,7 @@
 #pragma link C++ class o2::tpc::CalArray < unsigned> + ;
 #pragma link C++ class o2::tpc::CalArray < short> + ;
 #pragma link C++ class o2::tpc::CalArray < bool> + ;
+#pragma link C++ class o2::tpc::CalArray < o2::tpc::PadFlags> + ;
 #pragma link C++ class o2::tpc::CalDet < float> + ;
 #pragma link C++ class o2::tpc::CalDet < double> + ;
 #pragma link C++ class o2::tpc::CalDet < int> + ;

Detectors/TPC/base/src/TPCFlagsMemberCustomStreamer.cxx

@@ -0,0 +1,79 @@
+// Copyright 2019-2020 CERN and copyright holders of ALICE O2.
+// See https://alice-o2.web.cern.ch/copyright for details of the copyright holders.
+// All rights not expressly granted are reserved.
+//
+// This software is distributed under the terms of the GNU General Public
+// License v3 (GPL Version 3), copied verbatim in the file "COPYING".
+//
+// In applying this license CERN does not waive the privileges and immunities
+// granted to it by virtue of its status as an Intergovernmental Organization
+// or submit itself to any jurisdiction.
+
+#include "TPCBase/CalArray.h"
+#include <TMemberStreamer.h>
+#include <TBuffer.h>
+#include <DataFormatsTPC/Defs.h>
+#include <iostream>
+
+// to enable assert statements
+#ifdef NDEBUG
+#undef NDEBUG
+#include <cassert>
+#endif
+
+// The following code provides a specific ROOT I/O streaming method
+// for the mData member of CalArray<o2::tpc::PadFlags>
+// This member was written incorrectly to the TFile in ROOT versions < 6.36, causing
+// segfaults when reading on ARM64 (occassionally).
+// We continue to write it in the incorrect format and fix the reading back.
+
+// See also:
+// - https://github.com/root-project/root/pull/17009
+// - https://its.cern.ch/jira/browse/O2-4671
+
+void MemberVectorPadFlagsStreamer(TBuffer& R__b, void* objp, int n)
+{
+  if (n != 1) {
+    std::cerr << "Error in MemberVectorPadFlagsStreamer : Unexpected n " << n << std::endl;
+    return;
+  }
+  std::vector<o2::tpc::PadFlags>* obj = static_cast<std::vector<o2::tpc::PadFlags>*>(objp);
+  if (R__b.IsReading()) {
+    std::vector<int> R__stl;
+    R__stl.clear();
+    int R__n;
+    R__b >> R__n;
+    R__stl.reserve(R__n);
+    for (int R__i = 0; R__i < R__n; R__i++) {
+      Int_t readtemp;
+      R__b >> readtemp;
+      R__stl.push_back(readtemp);
+    }
+    auto data = reinterpret_cast<unsigned short*>(R__stl.data());
+    for (int i = 0; i < R__n; ++i) {
+      obj->push_back(static_cast<o2::tpc::PadFlags>(data[i]));
+    }
+  } else {
+    // We always save things with the old format.
+    R__b << (int)obj->size() / 2;
+    for (size_t i = 0; i < obj->size(); i++) {
+      R__b << (short)obj->at(i);
+    }
+  }
+}
+
+// register the streamer via static global initialization (on library load)
+namespace ROOT
+{
+static __attribute__((used)) int _R__dummyStreamer_3 =
+  ([]() {
+    auto cl = TClass::GetClass<o2::tpc::CalArray<o2::tpc::PadFlags>>();
+    if (cl) {
+      cl->AdoptMemberStreamer("mData", new TMemberStreamer(MemberVectorPadFlagsStreamer));
+    } else {
+      // we should never come here ... and if we do we should assert/fail
+      assert(false);
+    }
+    return 0;
+  })();
+} // namespace ROOT