DataFormats/GeometryCommonDetAlgo/interface/DeepCopyPointer.h - master - githubmirror/cmssw

DataFormats/GeometryCommonDetAlgo/interface/DeepCopyPointer.h
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09 май 2019, 07:14
09 май 2019, 07:1457cea53
#ifndef DeepCopyPointer_H
#define DeepCopyPointer_H

#include <algorithm>

/** A "smart" pointer that implements deep copy and ownership.
 *  In other words, when the pointer is copied it copies the 
 *  object it points to using "new". It also deletes the
 *  object it points to when it is deleted.
 *  Very useful for use as private data member of a class:
 *  it handles the copy construction, assignment, and destruction.
 */

template <class T>
class DeepCopyPointer {
public:
  ~DeepCopyPointer() { delete theData; }

  DeepCopyPointer() : theData(0) {}

  DeepCopyPointer(T* t) : theData(t) {}

  DeepCopyPointer(const DeepCopyPointer& other) {
    if (other.theData)
      theData = new T(*other);
    else
      theData = 0;
  }

  DeepCopyPointer& operator=(const DeepCopyPointer& other) {
    if (theData != other.theData) {
      delete theData;
      if (other.theData)
        theData = new T(*other);
      else
        theData = 0;
    }
    return *this;
  }

  // straight from http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2006/n2027.html
  DeepCopyPointer(DeepCopyPointer&& other) : theData(other.theData) { other.theData = 0; }
  DeepCopyPointer& operator=(DeepCopyPointer&& other) {
    std::swap(theData, other.theData);
    return *this;
  }

  /// Assing a new bare pointer to this DeepCopyPointer, taking ownership of it.
  /// The old content of this DeepCopyPointer is deleted
  void replaceWith(T* otherP) {
    if (theData != otherP) {
      delete theData;
      theData = otherP;
    }
  }

  // assume that the replacement object is of the very same class!
  // at the moment all the work is done by the client i.e.
  // call the distructor
  // new in place
  // with c++0X a templated method can encasulate it all here...
  T* replaceInplace() { return theData; }

  T& operator*() { return *theData; }
  const T& operator*() const { return *theData; }

  T* operator->() { return theData; }
  const T* operator->() const { return theData; }

  /// to allow test like " if (p) {...}"
  operator bool() const { return theData != 0; }

  /// to allow test like " if (p == &someT) {...}"
  bool operator==(const T* otherP) const { return theData == otherP; }

private:
  T* theData;
};

#endif  // DeepCopyPointer_H