.rootlogon.C

#include <string>

void _rootlogon() {
  // ensure we have format loaded. Should be able to move to C++20 fmt library
  // some point in the future
  R__LOAD_LIBRARY(libfmt);

  // check if we requested a special build directory through the environment,
  const char*       build_dir_from_env = gSystem->Getenv("ROOT_BUILD_TMPDIR");
  const std::string build_dir = build_dir_from_env ? build_dir_from_env : "$PWD/.root_build_dir";

  // ensure the build directory exists to avoid crashes due to it missing
  // note: in principle this allows us to execute arbitrary code, but seeing
  //       as this can only be manipulated through the shell environment in the
  //       first place this should not be a safety concern.
  const std::string mkdir = "mkdir -p " + build_dir;
  gSystem->Exec(mkdir.c_str());

  // Communicate what build directory we are using 
  std::cout << "---> Setting ACLiC build directory to: " << build_dir << "\n\n";
  // Make the ROOT build process use a flat build directory by setting
  // second arg to kTRUE.  This avoids an apparent race condition in ROOT
  // associated with child directory creation in the default 'kFALSE' mode.
  // The default mode will work correctly on the 2nd execution.  OK for
  // interactive use, but not great for the Farm environment.
  gSystem->SetBuildDir(build_dir.c_str(), kTRUE);

  // Ensure we have our environment setup
  gROOT->ProcessLine(".include /usr/local/include/hcana");
  gROOT->ProcessLine(".include SCRIPTS/include");
  gROOT->ProcessLine(".include .");

  // Some basic plotting setup
  gROOT->SetStyle("Plain");
  gStyle->SetPalette(1);

  // Load extra ROOT libraries, TODO check if this is still
  // needed in the newer ROOT versions we are using.
  gSystem->Load("libTree");
  gSystem->Load("libTreePlayer");
  gSystem->Load("libHist");
}