public void setOperation(@NotNull DirDiffOperation operation) {
    if (myType == DiffType.EQUAL || myType == DiffType.SEPARATOR) return;
    if (myType == DiffType.TARGET && operation == COPY_TO) return;
    if (myType == DiffType.SOURCE && operation == COPY_FROM) return;
    if (myType == DiffType.CHANGED && operation == DELETE) return;

    myOperation = operation;
  }
public void setOperation(@NotNull DirDiffOperation operation)