Method implForConstantPrimitiveKey

bolt/functions/sparksql/Map.cpp:290–385

  template <TypeKind Kind>
  void implForConstantPrimitiveKey(
      const SelectivityVector& rows,
      vector_size_t mapSize,
      std::vector<VectorPtr>& args,
      exec::DecodedArgs& decodedArgs,
      VectorPtr& result) const {
    using NativeType = typename TypeTraits<Kind>::NativeType;
    auto mapResult = result->as<MapVector>();
    auto rawSizes = mapResult->mutableSizes(rows.end())->asMutable<int32_t>();
    auto rawOffsets =
        mapResult->mutableOffsets(rows.end())->asMutable<int32_t>();

    auto& keysResult = mapResult->mapKeys();
    auto& valuesResult = mapResult->mapValues();
    vector_size_t offset = keysResult->size();

    folly::F14FastMap<NativeType, vector_size_t> keyToArgsIndex;
    keyToArgsIndex.reserve(mapSize);
    // 1. For constant keys, only one time-consuming duplication is required.
    for (vector_size_t i = 0; i < mapSize; i++) {
      auto key =
          decodedArgs.at(i * 2)->base()->as<ConstantVector<NativeType>>();
      BOLT_USER_CHECK(!key->isNullAt(0), "Cannot use null as map key!");
      if constexpr (Policy == EXCEPTION) {
        BOLT_USER_CHECK(
            keyToArgsIndex.insert({key->valueAtFast(0), i}).second,
            DuplicateKeyExceptionInfo);
      } else if constexpr (Policy == FIRST_WIN) {
        keyToArgsIndex.insert({key->valueAtFast(0), i});
      } else if constexpr (Policy == LAST_WIN) {
        keyToArgsIndex.insert_or_assign(key->valueAtFast(0), i);
      } else {
        BOLT_UNREACHABLE();
      }
    }

    auto mapSizeAfterDedup = keyToArgsIndex.size();
    rows.applyToSelected([&](vector_size_t row) {
      rawSizes[row] = mapSizeAfterDedup;
      rawOffsets[row] = offset;
      offset += mapSizeAfterDedup;
    });

    auto resultKeySize = offset;
    keysResult->resize(resultKeySize);
    valuesResult->resize(resultKeySize);
    auto flatKeysResult = keysResult->as<FlatVector<NativeType>>();
    BOLT_CHECK_NOT_NULL(flatKeysResult);
    auto rawKeysResult = flatKeysResult->mutableRawValues();

    auto beginRow = rows.begin();
    SelectivityVector targetRows(resultKeySize, false);
    vector_size_t targetIdx{0};
    std::vector<vector_size_t> toSourceRow(resultKeySize);

    // 2. Copy value and bool type keys to the result map column by column.
    // For other types of keys, copy first line from the args to the result
    // map, and then directly operate the `rawKeysResult` to memcpy the value of