Method SetOrAdd

oneflow/core/common/steady_vector.h:55–70

`index` should be <= size()

  // `index` should be <= size()
  void SetOrAdd(size_t index, T value) {
    std::unique_lock<std::mutex> lock(mutex_);
    size_t size = size_.load(std::memory_order_relaxed);
    CHECK_LE(index, size) << "index out of range";
    if (index == size) {
      int granularity = GetGranularity(size);
      if (size + 1 == (1 << granularity)) {
        CHECK_LT(granularity, N);
        granularity2data_[granularity].reset(new T[1 << granularity]);
      }
      *Mutable(index) = std::move(value);
      size_.fetch_add(1, std::memory_order_release);
    } else {
      *Mutable(index) = std::move(value);
    }
  }

  void push_back(const T& elem) { SetOrAdd(size_, elem); }