TFileDirectory.h

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#ifndef Utils_TFileDirectory_h
#define Utils_TFileDirectory_h
/* \class TFileDirectory
 *
 * \author Luca Lista, INFN
 *
 */
#include <string>
#include "FWCore/Utilities/interface/Exception.h"
#include "CommonTools/Utils/interface/TH1AddDirectorySentry.h"
#include "TFile.h"
#include "TDirectory.h"
#include "TClass.h"
#include "TH1.h"

namespace fwlite {
  class TFileService;
}

class TFileService;
class TFile;
class TDirectory;

class TFileDirectory {
public:
  TFileDirectory() : file_(nullptr), dir_(), descr_(), path_() {}

  virtual ~TFileDirectory() {}

  // cd()s to requested directory and returns true (if it is not
  // able to cd, it throws exception).
  bool cd() const;

  // returns a TDirectory pointer
  TDirectory *getBareDirectory(const std::string &subdir = "") const;

  // reutrns a "T" pointer matched to objname
  template <typename T>
  T *getObject(const std::string &objname, const std::string &subdir = "") {
    TObject *objPtr = _getObj(objname, subdir);
    // Ok, we've got it.  Let's see if it's a histogram
    T *retval = dynamic_cast<T *>(objPtr);
    if (!retval) {
      // object isn't a of class T
      throw cms::Exception("ObjectNotCorrectlyTyped") << "Object named " << objname << " is not of correct type";
    }
    return retval;
  }

  template <typename T, typename... Args>
  T *make(const Args &...args) const {
    TDirectory *d = _cd();
    T *t = new T(args...);
    ROOT::DirAutoAdd_t func = T::Class()->GetDirectoryAutoAdd();
    if (func) {
      TH1AddDirectorySentry sentry;
      func(t, d);
    } else {
      d->Append(t);
    }
    return t;
  }

  TFileDirectory mkdir(const std::string &dir, const std::string &descr = "");
  std::string fullPath() const;

private:
  TObject *_getObj(const std::string &objname, const std::string &subdir = "") const;

  TDirectory *_cd(const std::string &subdir = "", bool createNeededDirectories = true) const;

  // it's completely insane that this needs to be const since
  // 'mkdir' clearly changes things, but that's the way the cookie
  // crumbles...
  TDirectory *_mkdir(TDirectory *dirPtr, const std::string &dir, const std::string &description) const;

  TFileDirectory(const std::string &dir, const std::string &descr, TFile *file, const std::string &path)
      : file_(file), dir_(dir), descr_(descr), path_(path) {}
  friend class TFileService;
  friend class fwlite::TFileService;
  TFile *file_;
  std::string dir_, descr_, path_;
};

#endif