Function exportViews

bolt/vector/arrow/Bridge.cpp:916–1064

}

void exportViews(
    const FlatVector<StringView>& vec,
    const Selection& rows,
    const ArrowOptions& options,
    ArrowArray& out,
    memory::MemoryPool* pool,
    BoltToArrowBridgeHolder& holder) {
  auto stringBuffers = vec.stringBuffers();
  size_t numStringBuffers = stringBuffers.size();
  size_t nonInlineCnt = 0, scanned = 0;
  rows.apply([&](vector_size_t i) {
    ++scanned;
    if (!vec.isNullAt(i) && !vec.valueAtFast(i).isInline())
      ++nonInlineCnt;
  });
  bool rebuiltFallback = false;
  std::vector<uint64_t> fbOffsets;
  BufferPtr fbBuf;
  constexpr uint64_t kNoOffset = ~uint64_t{0};

  if (nonInlineCnt > 0 && numStringBuffers == 0 && options.exportToArrowIPC) {
    LOG(ERROR) << "[exportViews] non-inline strings but stringBuffers empty!";
    std::vector<uint64_t> fbOffsets;
    BufferPtr fbBuf;
    constexpr uint64_t kNoOffset = ~uint64_t{0};

    if (nonInlineCnt > 0 && numStringBuffers == 0) {
      LOG(WARNING) << "[exportViews] building fallback single string buffer";
      size_t totalBytes = 0;
      rows.apply([&](vector_size_t i) {
        if (!vec.isNullAt(i)) {
          auto sv = vec.valueAtFast(i);
          if (!sv.isInline())
            totalBytes += sv.size();
        }
      });

      if (totalBytes > 0) {
        fbBuf = AlignedBuffer::allocate<char>(totalBytes, pool);
        char* dst = fbBuf->asMutable<char>();

        fbOffsets.assign(out.length, kNoOffset);
        size_t cursor = 0;
        vector_size_t j = 0;
        rows.apply([&](vector_size_t i) {
          if (!vec.isNullAt(i)) {
            auto sv = vec.valueAtFast(i);
            if (!sv.isInline() && sv.size() > 0) {
              memcpy(dst + cursor, sv.data(), sv.size());
              fbOffsets[j] = cursor;
              cursor += sv.size();
            }
          }
          ++j;
        });

        stringBuffers.clear();
        stringBuffers.push_back(fbBuf);