Function STLClearObject

be/src/gutil/stl_util.h:69–75

// STL clear()/reserve(0) does not always free internal memory allocated
// This function uses swap/destructor to ensure the internal memory is freed.
template<class T> void STLClearObject(T* obj) {
  T tmp;
  tmp.swap(*obj);
  obj->reserve(0);  // this is because sometimes "T tmp" allocates objects with
                    // memory (arena implementation?).  use reserve()
                    // to clear() even if it doesn't always work
}

// Specialization for deque. Same as STLClearObject but doesn't call reserve
// since deque doesn't have reserve.