wgtmac commented on code in PR #54: URL: https://github.com/apache/iceberg-cpp/pull/54#discussion_r2020448679
########## src/iceberg/transform.h: ########## @@ -0,0 +1,81 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ + +#pragma once + +/// \file iceberg/transform.h + +#include <cstdint> +#include <memory> + +#include "iceberg/arrow_c_data_internal.h" +#include "iceberg/error.h" +#include "iceberg/expected.h" +#include "iceberg/iceberg_export.h" +#include "iceberg/type_fwd.h" +#include "iceberg/util/formattable.h" + +namespace iceberg { + +/// \brief Transform types used for partitioning +enum class TransformType : uint8_t { + /// Equal to source value, unmodified + kIdentity, + /// Hash of value, mod `N` + kBucket, + /// Value truncated to width `W` + kTruncate, + /// Extract a date or timestamp year, as years from 1970 + kYear, + /// Extract a date or timestamp month, as months from 1970-01-01 + kMonth, + /// Extract a date or timestamp day, as days from 1970-01-01 + kDay, + /// Extract a timestamp hour, as hours from 1970-01-01 00:00:00 + kHour, + /// Always produces `null` + kVoid, + /// Used to represent some customized transform that can't be recognized or supported now. + kUnknown, +}; + +/// \brief Get the relative transform name +constexpr std::string_view ToString(TransformType type) { + /// Transform names used for formatting + constexpr std::string_view TransformTypeNames[] = { + "Identity", "Bucket", "Truncate", "Year", "Month", "Day", "Hour", "Void", "Unknown" + }; + return TransformTypeNames[static_cast<size_t>(type)]; Review Comment: Is it undefined behavior to do this? ########## src/iceberg/transform.h: ########## @@ -0,0 +1,81 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ + +#pragma once + +/// \file iceberg/transform.h + +#include <cstdint> +#include <memory> + +#include "iceberg/arrow_c_data_internal.h" +#include "iceberg/error.h" +#include "iceberg/expected.h" +#include "iceberg/iceberg_export.h" +#include "iceberg/type_fwd.h" +#include "iceberg/util/formattable.h" + +namespace iceberg { + +/// \brief Transform types used for partitioning +enum class TransformType : uint8_t { + /// Equal to source value, unmodified + kIdentity, + /// Hash of value, mod `N` + kBucket, + /// Value truncated to width `W` + kTruncate, + /// Extract a date or timestamp year, as years from 1970 + kYear, + /// Extract a date or timestamp month, as months from 1970-01-01 + kMonth, + /// Extract a date or timestamp day, as days from 1970-01-01 + kDay, + /// Extract a timestamp hour, as hours from 1970-01-01 00:00:00 + kHour, + /// Always produces `null` + kVoid, + /// Used to represent some customized transform that can't be recognized or supported now. + kUnknown, +}; + +/// \brief Get the relative transform name +constexpr std::string_view ToString(TransformType type) { + /// Transform names used for formatting + constexpr std::string_view TransformTypeNames[] = { + "Identity", "Bucket", "Truncate", "Year", "Month", "Day", "Hour", "Void", "Unknown" + }; + return TransformTypeNames[static_cast<size_t>(type)]; +} + +/// \brief A transform function used for partitioning. +class ICEBERG_EXPORT TransformFunction : public util::Formattable { + public: + explicit TransformFunction(TransformType type); + /// \brief Transform an input array to a new array + [[nodiscard]] virtual expected<std::unique_ptr<ArrowArray>, Error> Transform(const ArrowArray& inputArrowArray) = 0; Review Comment: ```suggestion virtual expected<ArrowArray, Error> Transform(const ArrowArray& data) = 0; ``` `expected` already has `nodiscard` attribute in its definition, we don't need it here. For `ArrowArray`, usually we don't use `std::unique_ptr` since we have to explicitly call its release function. ########## src/iceberg/transform.h: ########## @@ -0,0 +1,81 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ + +#pragma once + +/// \file iceberg/transform.h + +#include <cstdint> +#include <memory> + +#include "iceberg/arrow_c_data_internal.h" Review Comment: Do not include any internal header in the public header file. To use Arrow C data, we can include `arrow_c_data.h`. ########## src/iceberg/transform.h: ########## @@ -0,0 +1,81 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ + +#pragma once + +/// \file iceberg/transform.h + +#include <cstdint> +#include <memory> + +#include "iceberg/arrow_c_data_internal.h" +#include "iceberg/error.h" +#include "iceberg/expected.h" +#include "iceberg/iceberg_export.h" +#include "iceberg/type_fwd.h" +#include "iceberg/util/formattable.h" + +namespace iceberg { + +/// \brief Transform types used for partitioning +enum class TransformType : uint8_t { + /// Equal to source value, unmodified + kIdentity, + /// Hash of value, mod `N` + kBucket, + /// Value truncated to width `W` + kTruncate, + /// Extract a date or timestamp year, as years from 1970 + kYear, + /// Extract a date or timestamp month, as months from 1970-01-01 + kMonth, + /// Extract a date or timestamp day, as days from 1970-01-01 + kDay, + /// Extract a timestamp hour, as hours from 1970-01-01 00:00:00 + kHour, + /// Always produces `null` + kVoid, + /// Used to represent some customized transform that can't be recognized or supported now. + kUnknown, Review Comment: What about putting `kUnknown` to the beginning? ########## test/transform_test.cc: ########## @@ -0,0 +1,66 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ + +#include "iceberg/transform.h" + +#include <format> +#include <memory> + +#include <gmock/gmock.h> +#include <gtest/gtest.h> + +#include "iceberg/util/formatter.h" + +TEST(TransformTest, TransformType) { + { + EXPECT_EQ("Identity", iceberg::ToString(iceberg::TransformType::kIdentity)); + EXPECT_EQ("Bucket", iceberg::ToString(iceberg::TransformType::kBucket)); + EXPECT_EQ("Truncate", iceberg::ToString(iceberg::TransformType::kTruncate)); + EXPECT_EQ("Year", iceberg::ToString(iceberg::TransformType::kYear)); + EXPECT_EQ("Month", iceberg::ToString(iceberg::TransformType::kMonth)); + EXPECT_EQ("Day", iceberg::ToString(iceberg::TransformType::kDay)); + EXPECT_EQ("Hour", iceberg::ToString(iceberg::TransformType::kHour)); + EXPECT_EQ("Void", iceberg::ToString(iceberg::TransformType::kVoid)); + EXPECT_EQ("Unknown", iceberg::ToString(iceberg::TransformType::kUnknown)); + } +} + +TEST(TransformTest, TransformFunction) { + class TestTransformFunction : public iceberg::TransformFunction { + public: + TestTransformFunction() : TransformFunction(iceberg::TransformType::kUnknown) {} + iceberg::expected<std::unique_ptr<ArrowArray>, iceberg::Error> Transform( + const ArrowArray& input) override { + return iceberg::unexpected(iceberg::Error{.kind = iceberg::ErrorKind::kNotSupported, + .message = "test transform function"}); + } + }; + + TestTransformFunction transform; + EXPECT_EQ(iceberg::TransformType::kUnknown, transform.transform_type()); + EXPECT_EQ("Unknown", transform.ToString()); + EXPECT_EQ("Unknown", std::format("{}", transform)); + + auto [_, arrow_array] = + iceberg::internal::CreateExampleArrowSchemaAndArrayByNanoarrow(); Review Comment: I will remove CreateExampleArrowSchemaAndArrayByNanoarrow some day. Perhaps add a TODO here? ########## test/transform_test.cc: ########## @@ -0,0 +1,66 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ + +#include "iceberg/transform.h" + +#include <format> +#include <memory> + +#include <gmock/gmock.h> +#include <gtest/gtest.h> + +#include "iceberg/util/formatter.h" + +TEST(TransformTest, TransformType) { + { + EXPECT_EQ("Identity", iceberg::ToString(iceberg::TransformType::kIdentity)); + EXPECT_EQ("Bucket", iceberg::ToString(iceberg::TransformType::kBucket)); + EXPECT_EQ("Truncate", iceberg::ToString(iceberg::TransformType::kTruncate)); + EXPECT_EQ("Year", iceberg::ToString(iceberg::TransformType::kYear)); + EXPECT_EQ("Month", iceberg::ToString(iceberg::TransformType::kMonth)); + EXPECT_EQ("Day", iceberg::ToString(iceberg::TransformType::kDay)); + EXPECT_EQ("Hour", iceberg::ToString(iceberg::TransformType::kHour)); + EXPECT_EQ("Void", iceberg::ToString(iceberg::TransformType::kVoid)); + EXPECT_EQ("Unknown", iceberg::ToString(iceberg::TransformType::kUnknown)); + } Review Comment: Add the `iceberg` namespace so we don't have to add `iceberg::` everywhere. ########## src/iceberg/exception.h: ########## @@ -38,4 +38,11 @@ class ICEBERG_EXPORT IcebergError : public std::runtime_error { explicit IcebergError(const std::string& what) : std::runtime_error(what) {} }; +#define ICEBERG_CHECK_FMT(condition, ...) \ Review Comment: ```suggestion #define ICEBERG_CHECK(condition, ...) \ ``` ########## src/iceberg/partition_field.h: ########## @@ -0,0 +1,78 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ + +#pragma once + +/// \file iceberg/partition_field.h +/// A partition field in a partition spec + +#include <cstdint> +#include <memory> +#include <string> +#include <string_view> + +#include "iceberg/iceberg_export.h" +#include "iceberg/type_fwd.h" +#include "iceberg/util/formattable.h" + +namespace iceberg { + +/// \brief a field with its transform. +class ICEBERG_EXPORT PartitionField : public util::Formattable { + public: + /// \brief Construct a field. + /// \param[in] source_id The source field ID. + /// \param[in] field_id The partition field ID. + /// \param[in] name The partition field name. + /// \param[in] transformType The transform type. + PartitionField(int32_t source_id, int32_t field_id, std::string name, TransformType transformType); + + /// \brief Get the source field ID. + [[nodiscard]] int32_t source_field_id() const; + + /// \brief Get the partition field ID. + [[nodiscard]] int32_t field_id() const; + + /// \brief Get the partition field name. + [[nodiscard]] std::string_view name() const; + + /// \brief Get the transform type. + [[nodiscard]] TransformType transform_type() const; Review Comment: I think so. Some transform types required additional parameters like bucket number or truncate length. ########## src/iceberg/partition_spec.h: ########## @@ -0,0 +1,73 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ + +#pragma once + +/// \file iceberg/partition_spec.h +/// Partition specs for Iceberg tables. + +#include <cstdint> +#include <string> +#include <vector> +#include <span> + +#include "iceberg/iceberg_export.h" +#include "iceberg/partition_field.h" + +namespace iceberg { + +/// \brief A partition spec for a Table. +/// +/// A partition spec is a list of partition fields, along with a unique integer ID. A +/// Table may have different partition specs over its lifetime due to partition spec +/// evolution. +class ICEBERG_EXPORT PartitionSpec { + public: + virtual ~PartitionSpec() = default; + PartitionSpec(int32_t spec_id, std::vector<PartitionField> fields); Review Comment: IMO, we need an `ArrowSchema` in the constructor to denote to the partition schema. ########## src/iceberg/partition_spec.h: ########## @@ -0,0 +1,73 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ + +#pragma once + +/// \file iceberg/partition_spec.h +/// Partition specs for Iceberg tables. + +#include <cstdint> +#include <string> +#include <vector> +#include <span> + +#include "iceberg/iceberg_export.h" +#include "iceberg/partition_field.h" + +namespace iceberg { + +/// \brief A partition spec for a Table. +/// +/// A partition spec is a list of partition fields, along with a unique integer ID. A +/// Table may have different partition specs over its lifetime due to partition spec +/// evolution. +class ICEBERG_EXPORT PartitionSpec { + public: + virtual ~PartitionSpec() = default; + PartitionSpec(int32_t spec_id, std::vector<PartitionField> fields); + /// \brief Get the spec ID. + [[nodiscard]] int32_t spec_id() const; + /// \brief Get a view of the partition fields. + [[nodiscard]] virtual std::span<const PartitionField> fields() const; + /// \brief Get a field by field ID. Review Comment: Perhaps we don't need these `GetFieldByXXX` at this moment? ########## test/transform_test.cc: ########## @@ -0,0 +1,66 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ + +#include "iceberg/transform.h" + +#include <format> +#include <memory> + +#include <gmock/gmock.h> +#include <gtest/gtest.h> + +#include "iceberg/util/formatter.h" + +TEST(TransformTest, TransformType) { + { + EXPECT_EQ("Identity", iceberg::ToString(iceberg::TransformType::kIdentity)); + EXPECT_EQ("Bucket", iceberg::ToString(iceberg::TransformType::kBucket)); + EXPECT_EQ("Truncate", iceberg::ToString(iceberg::TransformType::kTruncate)); + EXPECT_EQ("Year", iceberg::ToString(iceberg::TransformType::kYear)); + EXPECT_EQ("Month", iceberg::ToString(iceberg::TransformType::kMonth)); + EXPECT_EQ("Day", iceberg::ToString(iceberg::TransformType::kDay)); + EXPECT_EQ("Hour", iceberg::ToString(iceberg::TransformType::kHour)); + EXPECT_EQ("Void", iceberg::ToString(iceberg::TransformType::kVoid)); + EXPECT_EQ("Unknown", iceberg::ToString(iceberg::TransformType::kUnknown)); + } Review Comment: ```suggestion EXPECT_EQ("Identity", iceberg::ToString(iceberg::TransformType::kIdentity)); EXPECT_EQ("Bucket", iceberg::ToString(iceberg::TransformType::kBucket)); EXPECT_EQ("Truncate", iceberg::ToString(iceberg::TransformType::kTruncate)); EXPECT_EQ("Year", iceberg::ToString(iceberg::TransformType::kYear)); EXPECT_EQ("Month", iceberg::ToString(iceberg::TransformType::kMonth)); EXPECT_EQ("Day", iceberg::ToString(iceberg::TransformType::kDay)); EXPECT_EQ("Hour", iceberg::ToString(iceberg::TransformType::kHour)); EXPECT_EQ("Void", iceberg::ToString(iceberg::TransformType::kVoid)); EXPECT_EQ("Unknown", iceberg::ToString(iceberg::TransformType::kUnknown)); ``` ########## src/iceberg/partition_field.h: ########## @@ -0,0 +1,78 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ + +#pragma once + +/// \file iceberg/partition_field.h +/// A partition field in a partition spec + +#include <cstdint> +#include <memory> +#include <string> +#include <string_view> + +#include "iceberg/iceberg_export.h" +#include "iceberg/type_fwd.h" +#include "iceberg/util/formattable.h" + +namespace iceberg { + +/// \brief a field with its transform. +class ICEBERG_EXPORT PartitionField : public util::Formattable { + public: + /// \brief Construct a field. + /// \param[in] source_id The source field ID. + /// \param[in] field_id The partition field ID. + /// \param[in] name The partition field name. + /// \param[in] transformType The transform type. + PartitionField(int32_t source_id, int32_t field_id, std::string name, TransformType transformType); + + /// \brief Get the source field ID. + [[nodiscard]] int32_t source_field_id() const; + + /// \brief Get the partition field ID. + [[nodiscard]] int32_t field_id() const; + + /// \brief Get the partition field name. + [[nodiscard]] std::string_view name() const; + + /// \brief Get the transform type. + [[nodiscard]] TransformType transform_type() const; + + [[nodiscard]] std::string ToString() const override; + + friend bool operator==(const PartitionField& lhs, const PartitionField& rhs) { + return lhs.Equals(rhs); + } + + friend bool operator!=(const PartitionField& lhs, const PartitionField& rhs) { + return !(lhs == rhs); + } + + private: + /// \brief Compare two fields for equality. + [[nodiscard]] bool Equals(const PartitionField& other) const; + + int32_t source_field_id_; Review Comment: Should we consider multi-argument transform here? In that case, a partition field might have more than one source field ids. See https://docs.google.com/document/d/1aDoZqRgvDOOUVAGhvKZbp5vFstjsAMY4EFCyjlxpaaw ########## src/iceberg/transform.h: ########## @@ -0,0 +1,81 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ + +#pragma once + +/// \file iceberg/transform.h + +#include <cstdint> +#include <memory> + +#include "iceberg/arrow_c_data_internal.h" +#include "iceberg/error.h" +#include "iceberg/expected.h" +#include "iceberg/iceberg_export.h" +#include "iceberg/type_fwd.h" +#include "iceberg/util/formattable.h" + +namespace iceberg { + +/// \brief Transform types used for partitioning +enum class TransformType : uint8_t { + /// Equal to source value, unmodified + kIdentity, + /// Hash of value, mod `N` + kBucket, + /// Value truncated to width `W` + kTruncate, + /// Extract a date or timestamp year, as years from 1970 + kYear, + /// Extract a date or timestamp month, as months from 1970-01-01 + kMonth, + /// Extract a date or timestamp day, as days from 1970-01-01 + kDay, + /// Extract a timestamp hour, as hours from 1970-01-01 00:00:00 + kHour, + /// Always produces `null` + kVoid, + /// Used to represent some customized transform that can't be recognized or supported now. + kUnknown, +}; + +/// \brief Get the relative transform name +constexpr std::string_view ToString(TransformType type) { + /// Transform names used for formatting + constexpr std::string_view TransformTypeNames[] = { + "Identity", "Bucket", "Truncate", "Year", "Month", "Day", "Hour", "Void", "Unknown" + }; + return TransformTypeNames[static_cast<size_t>(type)]; +} + +/// \brief A transform function used for partitioning. +class ICEBERG_EXPORT TransformFunction : public util::Formattable { + public: + explicit TransformFunction(TransformType type); + /// \brief Transform an input array to a new array + [[nodiscard]] virtual expected<std::unique_ptr<ArrowArray>, Error> Transform(const ArrowArray& inputArrowArray) = 0; + /// \brief Get the transform type + [[nodiscard]] virtual TransformType transform_type() const; + [[nodiscard]] std::string ToString() const override; Review Comment: ```suggestion virtual TransformType transform_type() const; std::string ToString() const override; ``` I don't think we need to add nodiscard to these functions. -- This is an automated message from the Apache Git Service. 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