Function exportRowToArrowSchema

bolt/vector/arrow/Bridge.cpp:2109–2165

void exportArrayToArrowSchema(
    const ArrayVector& arrays,
    ArrowSchema& arrowSchema,
    const ArrowOptions& options,
    BoltToArrowSchemaBridgeHolder* bridgeHolder,
    memory::MemoryPool* pool) {
  auto& type = arrays.type();
  auto child = std::make_unique<ArrowSchema>();
  BOLT_CHECK(
      arrays.elements()->type()->equivalent(*type->asArray().elementType()),
      "array vector child type: {}, type child: {}",
      arrays.elements()->type()->toString(),
      type->asArray().elementType()->toString());
  exportToArrow(arrays.elements(), *child, options, {}, pool);
  // Name is required, and "item" is the default name used in arrow itself.
  child->name = "item";
  bridgeHolder->setChildAtIndex(0, std::move(child), arrowSchema);
}

void exportVariantToArrowSchema(
    const VariantVector& variant,
    ArrowSchema& arrowSchema,
    const ArrowOptions& options,
    BoltToArrowSchemaBridgeHolder* bridgeHolder,
    memory::MemoryPool* pool) {
  auto numChildren = variant.childrenSize();
  bridgeHolder->childrenRaw.resize(numChildren);
  bridgeHolder->childrenOwned.resize(numChildren);
  for (column_index_t i = 0; i < numChildren; ++i) {
    auto child = std::make_unique<ArrowSchema>();
    exportToArrow(variant.childAt(i), *child, options, {}, pool);
    child->name = (i == 0) ? "value" : "metadata";
    bridgeHolder->setChildAtIndex(i, std::move(child), arrowSchema);
  }
  setArrowMetadataEntry(
      arrowSchema,
      *bridgeHolder,
      kArrowExtensionNameKey,
      kSparkVariantExtensionName);
}

void exportRowToArrowSchema(
    const RowVector& rows,
    ArrowSchema& arrowSchema,
    const ArrowOptions& options,
    BoltToArrowSchemaBridgeHolder* bridgeHolder,
    const std::vector<std::string>& fieldNames,
    memory::MemoryPool* pool) {
  auto& type = rows.type();
  auto numChildren = rows.childrenSize();
  bridgeHolder->childrenRaw.resize(numChildren);
  bridgeHolder->childrenOwned.resize(numChildren);

  // Hold the shared_ptr so we can set the ArrowSchema.name pointer to its
  // internal `name` string.
  bridgeHolder->rowType = std::static_pointer_cast<const RowType>(type);

  arrowSchema.children = bridgeHolder->childrenRaw.data();
  arrowSchema.n_children = numChildren;