wgtmac commented on code in PR #77: URL: https://github.com/apache/iceberg-cpp/pull/77#discussion_r2047239865
########## src/iceberg/struct_like.h: ########## @@ -0,0 +1,278 @@ +/* + * 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 + +#include <string> +#include <vector> + +#include "iceberg/iceberg_export.h" +#include "iceberg/result.h" +#include "iceberg/type.h" + +namespace iceberg { + +class Scalar; +class StructScalar; +class ArrayScalar; +class ScalarVisitor; +class StructLike; +class StructLikeVisitor; +/** + * @brief Base class representing a generic scalar value. + */ +class ICEBERG_EXPORT Scalar { + public: + virtual ~Scalar() = default; + + /** + * @brief Checks if the scalar represents a null value. + * @return true if the value is null, false otherwise. + */ + virtual bool IsNull() const = 0; + + /** + * @brief Casts the scalar to a specific derived type. + * @tparam T The target derived Scalar type. + * @return Reference to the casted value. + * @throws std::bad_cast if the cast fails. + */ + template <typename T> + const T& as() const { + auto ptr = dynamic_cast<const T*>(this); + if (!ptr) throw std::bad_cast(); + return *ptr; + } + + /** + * @brief Creates a deep copy of the scalar. + * @return A shared pointer to the cloned scalar. + */ + virtual std::shared_ptr<Scalar> clone() const = 0; + + /** + * @brief Accepts a visitor for dispatching based on scalar type. + * @param visitor The visitor to accept. + */ + virtual void accept(ScalarVisitor& visitor) const = 0; +}; + +/** + * @brief Visitor interface for Scalar, supporting type-dispatched operations. + */ +class ICEBERG_EXPORT ScalarVisitor { + public: + virtual ~ScalarVisitor() = default; + + /// Visit methods for primitive types + virtual void visit(int32_t value) = 0; + virtual void visit(int64_t value) = 0; + virtual void visit(float value) = 0; + virtual void visit(double value) = 0; + virtual void visit(bool value) = 0; + virtual void visit(const std::string& value) = 0; + + /** + * @brief Called when visiting a null scalar. + */ + virtual void visitNull() = 0; + + /// Visit methods for complex types + virtual void visitStruct(const StructScalar& value) = 0; + virtual void visitArray(const ArrayScalar& value) = 0; +}; + +/** + * @brief Represents a scalar that holds a primitive value. + * @tparam T The type of the primitive value. + */ +template <typename T> +class ICEBERG_EXPORT PrimitiveScalar : public Scalar { + public: + /** + * @brief Constructs a PrimitiveScalar from an optional value. + * @param value The optional primitive value. + */ + explicit PrimitiveScalar(std::optional<T> value) : value_(std::move(value)) {} + + bool IsNull() const override { return !value_.has_value(); } + + /** + * @brief Gets the actual value held by the scalar. + * @return Reference to the value. + * @note Behavior is undefined if the scalar is null. + */ + const T& value() const { return *value_; } + + /** + * @brief (Deprecated) Type-specific accessor for raw value. + * @tparam U Must match T. + * @return Reference to the value if types match. + * @throws std::bad_cast if U does not match T. + */ + template <typename U> + const U& as() const { + if constexpr (std::is_same_v<T, U>) return *value_; + throw std::bad_cast(); + } + + std::shared_ptr<Scalar> clone() const override { + return std::make_shared<PrimitiveScalar<T>>(value_); + } + + void accept(ScalarVisitor& visitor) const override { + if (IsNull()) { + visitor.visitNull(); + } else { + visitor.visit(*value_); + } + } + + private: + std::optional<T> value_; +}; + +// Aliases for common primitive scalar types +using Int32Scalar = PrimitiveScalar<int32_t>; +using Int64Scalar = PrimitiveScalar<int64_t>; +using DoubleScalar = PrimitiveScalar<double>; +using StringScalar = PrimitiveScalar<std::string>; +using BoolScalar = PrimitiveScalar<bool>; + +/** + * @brief Base class for scalars that contain a vector of child Scalars. + * @tparam Derived The concrete subclass type (CRTP). + */ +template <typename Derived> +class VectorScalarBase : public Scalar { Review Comment: It is a little bit weird that values in it have different meanings in the `StructScalar` (horizontal) and `ArrayScalar` (vertical). ########## src/iceberg/struct_like.h: ########## @@ -0,0 +1,278 @@ +/* + * 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 + +#include <string> +#include <vector> + +#include "iceberg/iceberg_export.h" +#include "iceberg/result.h" +#include "iceberg/type.h" + +namespace iceberg { + +class Scalar; +class StructScalar; +class ArrayScalar; +class ScalarVisitor; +class StructLike; +class StructLikeVisitor; +/** + * @brief Base class representing a generic scalar value. + */ +class ICEBERG_EXPORT Scalar { + public: + virtual ~Scalar() = default; + + /** + * @brief Checks if the scalar represents a null value. + * @return true if the value is null, false otherwise. + */ + virtual bool IsNull() const = 0; + + /** + * @brief Casts the scalar to a specific derived type. + * @tparam T The target derived Scalar type. + * @return Reference to the casted value. + * @throws std::bad_cast if the cast fails. + */ + template <typename T> + const T& as() const { + auto ptr = dynamic_cast<const T*>(this); + if (!ptr) throw std::bad_cast(); + return *ptr; + } + + /** + * @brief Creates a deep copy of the scalar. + * @return A shared pointer to the cloned scalar. + */ + virtual std::shared_ptr<Scalar> clone() const = 0; + + /** + * @brief Accepts a visitor for dispatching based on scalar type. + * @param visitor The visitor to accept. + */ + virtual void accept(ScalarVisitor& visitor) const = 0; +}; + +/** + * @brief Visitor interface for Scalar, supporting type-dispatched operations. + */ +class ICEBERG_EXPORT ScalarVisitor { + public: + virtual ~ScalarVisitor() = default; + + /// Visit methods for primitive types + virtual void visit(int32_t value) = 0; Review Comment: Shouldn't it accept `Int32Scalar`? ########## src/iceberg/struct_like.h: ########## @@ -0,0 +1,278 @@ +/* + * 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 + +#include <string> +#include <vector> + +#include "iceberg/iceberg_export.h" +#include "iceberg/result.h" +#include "iceberg/type.h" + +namespace iceberg { + +class Scalar; +class StructScalar; +class ArrayScalar; +class ScalarVisitor; +class StructLike; +class StructLikeVisitor; +/** + * @brief Base class representing a generic scalar value. + */ +class ICEBERG_EXPORT Scalar { + public: + virtual ~Scalar() = default; + + /** + * @brief Checks if the scalar represents a null value. + * @return true if the value is null, false otherwise. + */ + virtual bool IsNull() const = 0; + + /** + * @brief Casts the scalar to a specific derived type. + * @tparam T The target derived Scalar type. + * @return Reference to the casted value. + * @throws std::bad_cast if the cast fails. + */ + template <typename T> + const T& as() const { + auto ptr = dynamic_cast<const T*>(this); + if (!ptr) throw std::bad_cast(); + return *ptr; + } + + /** + * @brief Creates a deep copy of the scalar. + * @return A shared pointer to the cloned scalar. + */ + virtual std::shared_ptr<Scalar> clone() const = 0; + + /** + * @brief Accepts a visitor for dispatching based on scalar type. + * @param visitor The visitor to accept. + */ + virtual void accept(ScalarVisitor& visitor) const = 0; +}; + +/** + * @brief Visitor interface for Scalar, supporting type-dispatched operations. + */ +class ICEBERG_EXPORT ScalarVisitor { + public: + virtual ~ScalarVisitor() = default; + + /// Visit methods for primitive types + virtual void visit(int32_t value) = 0; + virtual void visit(int64_t value) = 0; + virtual void visit(float value) = 0; + virtual void visit(double value) = 0; + virtual void visit(bool value) = 0; + virtual void visit(const std::string& value) = 0; + + /** + * @brief Called when visiting a null scalar. + */ + virtual void visitNull() = 0; + + /// Visit methods for complex types + virtual void visitStruct(const StructScalar& value) = 0; + virtual void visitArray(const ArrayScalar& value) = 0; +}; + +/** + * @brief Represents a scalar that holds a primitive value. + * @tparam T The type of the primitive value. + */ +template <typename T> +class ICEBERG_EXPORT PrimitiveScalar : public Scalar { + public: + /** + * @brief Constructs a PrimitiveScalar from an optional value. + * @param value The optional primitive value. + */ + explicit PrimitiveScalar(std::optional<T> value) : value_(std::move(value)) {} + + bool IsNull() const override { return !value_.has_value(); } + + /** + * @brief Gets the actual value held by the scalar. + * @return Reference to the value. + * @note Behavior is undefined if the scalar is null. + */ + const T& value() const { return *value_; } + + /** + * @brief (Deprecated) Type-specific accessor for raw value. + * @tparam U Must match T. + * @return Reference to the value if types match. + * @throws std::bad_cast if U does not match T. + */ + template <typename U> + const U& as() const { + if constexpr (std::is_same_v<T, U>) return *value_; + throw std::bad_cast(); + } + + std::shared_ptr<Scalar> clone() const override { + return std::make_shared<PrimitiveScalar<T>>(value_); + } + + void accept(ScalarVisitor& visitor) const override { + if (IsNull()) { + visitor.visitNull(); + } else { + visitor.visit(*value_); + } + } + + private: + std::optional<T> value_; +}; + +// Aliases for common primitive scalar types +using Int32Scalar = PrimitiveScalar<int32_t>; +using Int64Scalar = PrimitiveScalar<int64_t>; +using DoubleScalar = PrimitiveScalar<double>; +using StringScalar = PrimitiveScalar<std::string>; +using BoolScalar = PrimitiveScalar<bool>; + +/** + * @brief Base class for scalars that contain a vector of child Scalars. + * @tparam Derived The concrete subclass type (CRTP). + */ +template <typename Derived> +class VectorScalarBase : public Scalar { + public: + /** + * @brief Constructs a VectorScalarBase. + * @param values Child scalar values. + * @param is_null Whether the entire scalar is null. + */ + explicit VectorScalarBase(std::vector<std::shared_ptr<Scalar>> values, + bool is_null = false) + : values_(std::move(values)), is_null_(is_null) {} + + /** + * @brief Gets the child scalar values. + * @return Vector of shared pointers to child Scalars. + */ + const std::vector<std::shared_ptr<Scalar>>& value() const { return values_; } + + bool IsNull() const override { return is_null_; } + + std::shared_ptr<Scalar> clone() const override { + std::vector<std::shared_ptr<Scalar>> cloned; + for (const auto& v : values_) { + cloned.push_back(v->clone()); + } + return std::make_shared<Derived>(std::move(cloned), is_null_); + } + + protected: + std::vector<std::shared_ptr<Scalar>> values_; + bool is_null_; +}; + +/** + * @brief Represents a struct-like scalar (tuple of fields). + */ +class StructScalar : public VectorScalarBase<StructScalar> { + public: + using VectorScalarBase::VectorScalarBase; + + void accept(ScalarVisitor& visitor) const override { + if (IsNull()) { + visitor.visitNull(); + } else { + visitor.visitStruct(*this); + } + } +}; + +/** + * @brief Represents an array-like scalar (list of values). + */ +class ArrayScalar : public VectorScalarBase<ArrayScalar> { + public: + using VectorScalarBase::VectorScalarBase; + + void accept(ScalarVisitor& visitor) const override { + if (IsNull()) { + visitor.visitNull(); + } else { + visitor.visitArray(*this); + } + } +}; + +/** + * @brief Abstract interface for structured field access. + */ +class ICEBERG_EXPORT StructLike { Review Comment: Can't we simply reuse `StructScalar`? ########## src/iceberg/struct_like.h: ########## @@ -0,0 +1,278 @@ +/* + * 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 + +#include <string> +#include <vector> + +#include "iceberg/iceberg_export.h" +#include "iceberg/result.h" +#include "iceberg/type.h" + +namespace iceberg { + +class Scalar; +class StructScalar; +class ArrayScalar; +class ScalarVisitor; +class StructLike; +class StructLikeVisitor; +/** + * @brief Base class representing a generic scalar value. + */ +class ICEBERG_EXPORT Scalar { + public: + virtual ~Scalar() = default; + + /** + * @brief Checks if the scalar represents a null value. + * @return true if the value is null, false otherwise. + */ + virtual bool IsNull() const = 0; + + /** + * @brief Casts the scalar to a specific derived type. + * @tparam T The target derived Scalar type. + * @return Reference to the casted value. + * @throws std::bad_cast if the cast fails. + */ + template <typename T> + const T& as() const { + auto ptr = dynamic_cast<const T*>(this); + if (!ptr) throw std::bad_cast(); + return *ptr; + } + + /** + * @brief Creates a deep copy of the scalar. + * @return A shared pointer to the cloned scalar. + */ + virtual std::shared_ptr<Scalar> clone() const = 0; + + /** + * @brief Accepts a visitor for dispatching based on scalar type. + * @param visitor The visitor to accept. + */ + virtual void accept(ScalarVisitor& visitor) const = 0; +}; + +/** + * @brief Visitor interface for Scalar, supporting type-dispatched operations. + */ +class ICEBERG_EXPORT ScalarVisitor { + public: + virtual ~ScalarVisitor() = default; + + /// Visit methods for primitive types + virtual void visit(int32_t value) = 0; + virtual void visit(int64_t value) = 0; + virtual void visit(float value) = 0; + virtual void visit(double value) = 0; + virtual void visit(bool value) = 0; + virtual void visit(const std::string& value) = 0; + + /** + * @brief Called when visiting a null scalar. + */ + virtual void visitNull() = 0; + + /// Visit methods for complex types + virtual void visitStruct(const StructScalar& value) = 0; + virtual void visitArray(const ArrayScalar& value) = 0; +}; + +/** + * @brief Represents a scalar that holds a primitive value. + * @tparam T The type of the primitive value. + */ +template <typename T> +class ICEBERG_EXPORT PrimitiveScalar : public Scalar { + public: + /** + * @brief Constructs a PrimitiveScalar from an optional value. + * @param value The optional primitive value. + */ + explicit PrimitiveScalar(std::optional<T> value) : value_(std::move(value)) {} + + bool IsNull() const override { return !value_.has_value(); } + + /** + * @brief Gets the actual value held by the scalar. + * @return Reference to the value. + * @note Behavior is undefined if the scalar is null. + */ + const T& value() const { return *value_; } + + /** + * @brief (Deprecated) Type-specific accessor for raw value. + * @tparam U Must match T. + * @return Reference to the value if types match. + * @throws std::bad_cast if U does not match T. + */ + template <typename U> + const U& as() const { + if constexpr (std::is_same_v<T, U>) return *value_; + throw std::bad_cast(); + } + + std::shared_ptr<Scalar> clone() const override { + return std::make_shared<PrimitiveScalar<T>>(value_); + } + + void accept(ScalarVisitor& visitor) const override { + if (IsNull()) { + visitor.visitNull(); + } else { + visitor.visit(*value_); + } + } + + private: + std::optional<T> value_; +}; + +// Aliases for common primitive scalar types +using Int32Scalar = PrimitiveScalar<int32_t>; +using Int64Scalar = PrimitiveScalar<int64_t>; +using DoubleScalar = PrimitiveScalar<double>; +using StringScalar = PrimitiveScalar<std::string>; +using BoolScalar = PrimitiveScalar<bool>; + +/** + * @brief Base class for scalars that contain a vector of child Scalars. + * @tparam Derived The concrete subclass type (CRTP). + */ +template <typename Derived> +class VectorScalarBase : public Scalar { + public: + /** + * @brief Constructs a VectorScalarBase. + * @param values Child scalar values. + * @param is_null Whether the entire scalar is null. + */ + explicit VectorScalarBase(std::vector<std::shared_ptr<Scalar>> values, + bool is_null = false) + : values_(std::move(values)), is_null_(is_null) {} + + /** + * @brief Gets the child scalar values. + * @return Vector of shared pointers to child Scalars. + */ + const std::vector<std::shared_ptr<Scalar>>& value() const { return values_; } + + bool IsNull() const override { return is_null_; } + + std::shared_ptr<Scalar> clone() const override { + std::vector<std::shared_ptr<Scalar>> cloned; + for (const auto& v : values_) { + cloned.push_back(v->clone()); + } + return std::make_shared<Derived>(std::move(cloned), is_null_); + } + + protected: + std::vector<std::shared_ptr<Scalar>> values_; + bool is_null_; +}; + +/** + * @brief Represents a struct-like scalar (tuple of fields). + */ +class StructScalar : public VectorScalarBase<StructScalar> { + public: + using VectorScalarBase::VectorScalarBase; + + void accept(ScalarVisitor& visitor) const override { + if (IsNull()) { + visitor.visitNull(); + } else { + visitor.visitStruct(*this); + } + } +}; + +/** + * @brief Represents an array-like scalar (list of values). + */ +class ArrayScalar : public VectorScalarBase<ArrayScalar> { + public: + using VectorScalarBase::VectorScalarBase; + + void accept(ScalarVisitor& visitor) const override { + if (IsNull()) { + visitor.visitNull(); + } else { + visitor.visitArray(*this); + } + } +}; + +/** + * @brief Abstract interface for structured field access. + */ +class ICEBERG_EXPORT StructLike { + public: + virtual ~StructLike() = default; + + /** + * @brief Gets the type of the structure. + * @return Reference to the StructType. + */ + virtual const StructType& struct_type() const = 0; + + /** + * @brief Gets the number of fields. + * @return Number of fields. + */ + virtual int32_t size() const = 0; + + /** + * @brief Gets the value of a field by position. + * @param pos The zero-based index of the field. + * @return Reference to the scalar value. + */ + virtual const Scalar& get(int32_t pos) const = 0; + + /** + * @brief Sets the value of a field by position. + * @param pos The zero-based index of the field. + * @param value The scalar to assign. + * @return Status indicating success or failure. + */ + virtual Status set(int32_t pos, std::shared_ptr<Scalar> value) = 0; +}; + +/** + * @brief Visitor interface for traversing StructLike fields. + */ +class ICEBERG_EXPORT StructLikeVisitor { Review Comment: ditto, we can remove this as well. ########## src/iceberg/struct_like.h: ########## @@ -0,0 +1,278 @@ +/* + * 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 + +#include <string> +#include <vector> + +#include "iceberg/iceberg_export.h" +#include "iceberg/result.h" +#include "iceberg/type.h" + +namespace iceberg { + +class Scalar; +class StructScalar; +class ArrayScalar; +class ScalarVisitor; +class StructLike; +class StructLikeVisitor; +/** + * @brief Base class representing a generic scalar value. + */ +class ICEBERG_EXPORT Scalar { + public: + virtual ~Scalar() = default; + + /** + * @brief Checks if the scalar represents a null value. + * @return true if the value is null, false otherwise. + */ + virtual bool IsNull() const = 0; + + /** + * @brief Casts the scalar to a specific derived type. + * @tparam T The target derived Scalar type. + * @return Reference to the casted value. + * @throws std::bad_cast if the cast fails. + */ + template <typename T> + const T& as() const { + auto ptr = dynamic_cast<const T*>(this); + if (!ptr) throw std::bad_cast(); + return *ptr; + } + + /** + * @brief Creates a deep copy of the scalar. + * @return A shared pointer to the cloned scalar. + */ + virtual std::shared_ptr<Scalar> clone() const = 0; + + /** + * @brief Accepts a visitor for dispatching based on scalar type. + * @param visitor The visitor to accept. + */ + virtual void accept(ScalarVisitor& visitor) const = 0; +}; + +/** + * @brief Visitor interface for Scalar, supporting type-dispatched operations. + */ +class ICEBERG_EXPORT ScalarVisitor { + public: + virtual ~ScalarVisitor() = default; + + /// Visit methods for primitive types + virtual void visit(int32_t value) = 0; + virtual void visit(int64_t value) = 0; + virtual void visit(float value) = 0; + virtual void visit(double value) = 0; + virtual void visit(bool value) = 0; + virtual void visit(const std::string& value) = 0; + + /** + * @brief Called when visiting a null scalar. + */ + virtual void visitNull() = 0; + + /// Visit methods for complex types + virtual void visitStruct(const StructScalar& value) = 0; + virtual void visitArray(const ArrayScalar& value) = 0; +}; + +/** + * @brief Represents a scalar that holds a primitive value. + * @tparam T The type of the primitive value. + */ +template <typename T> +class ICEBERG_EXPORT PrimitiveScalar : public Scalar { + public: + /** + * @brief Constructs a PrimitiveScalar from an optional value. + * @param value The optional primitive value. + */ + explicit PrimitiveScalar(std::optional<T> value) : value_(std::move(value)) {} + + bool IsNull() const override { return !value_.has_value(); } + + /** + * @brief Gets the actual value held by the scalar. + * @return Reference to the value. + * @note Behavior is undefined if the scalar is null. + */ + const T& value() const { return *value_; } + + /** + * @brief (Deprecated) Type-specific accessor for raw value. + * @tparam U Must match T. + * @return Reference to the value if types match. + * @throws std::bad_cast if U does not match T. + */ + template <typename U> + const U& as() const { + if constexpr (std::is_same_v<T, U>) return *value_; + throw std::bad_cast(); + } + + std::shared_ptr<Scalar> clone() const override { + return std::make_shared<PrimitiveScalar<T>>(value_); + } + + void accept(ScalarVisitor& visitor) const override { + if (IsNull()) { + visitor.visitNull(); + } else { + visitor.visit(*value_); + } + } + + private: + std::optional<T> value_; +}; + +// Aliases for common primitive scalar types +using Int32Scalar = PrimitiveScalar<int32_t>; +using Int64Scalar = PrimitiveScalar<int64_t>; +using DoubleScalar = PrimitiveScalar<double>; +using StringScalar = PrimitiveScalar<std::string>; +using BoolScalar = PrimitiveScalar<bool>; + +/** + * @brief Base class for scalars that contain a vector of child Scalars. + * @tparam Derived The concrete subclass type (CRTP). + */ +template <typename Derived> +class VectorScalarBase : public Scalar { + public: + /** + * @brief Constructs a VectorScalarBase. + * @param values Child scalar values. + * @param is_null Whether the entire scalar is null. + */ + explicit VectorScalarBase(std::vector<std::shared_ptr<Scalar>> values, + bool is_null = false) + : values_(std::move(values)), is_null_(is_null) {} + + /** + * @brief Gets the child scalar values. + * @return Vector of shared pointers to child Scalars. + */ + const std::vector<std::shared_ptr<Scalar>>& value() const { return values_; } + + bool IsNull() const override { return is_null_; } + + std::shared_ptr<Scalar> clone() const override { + std::vector<std::shared_ptr<Scalar>> cloned; + for (const auto& v : values_) { + cloned.push_back(v->clone()); + } + return std::make_shared<Derived>(std::move(cloned), is_null_); + } + + protected: + std::vector<std::shared_ptr<Scalar>> values_; + bool is_null_; +}; + +/** + * @brief Represents a struct-like scalar (tuple of fields). + */ +class StructScalar : public VectorScalarBase<StructScalar> { + public: + using VectorScalarBase::VectorScalarBase; + + void accept(ScalarVisitor& visitor) const override { + if (IsNull()) { + visitor.visitNull(); + } else { + visitor.visitStruct(*this); + } + } +}; + +/** + * @brief Represents an array-like scalar (list of values). + */ +class ArrayScalar : public VectorScalarBase<ArrayScalar> { Review Comment: How do we define `MapScalar`? Should it be `array<struct<key,value>>`? ########## src/iceberg/struct_like.h: ########## @@ -0,0 +1,278 @@ +/* + * 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 + +#include <string> +#include <vector> + +#include "iceberg/iceberg_export.h" +#include "iceberg/result.h" +#include "iceberg/type.h" + +namespace iceberg { + +class Scalar; +class StructScalar; +class ArrayScalar; +class ScalarVisitor; +class StructLike; +class StructLikeVisitor; +/** + * @brief Base class representing a generic scalar value. + */ +class ICEBERG_EXPORT Scalar { Review Comment: Should we make `std::shared_ptr<Type>` as a member variable to `Scalar`? ########## src/iceberg/struct_like.h: ########## @@ -0,0 +1,278 @@ +/* + * 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 + +#include <string> +#include <vector> + +#include "iceberg/iceberg_export.h" +#include "iceberg/result.h" +#include "iceberg/type.h" + +namespace iceberg { + +class Scalar; +class StructScalar; +class ArrayScalar; +class ScalarVisitor; +class StructLike; +class StructLikeVisitor; +/** + * @brief Base class representing a generic scalar value. + */ +class ICEBERG_EXPORT Scalar { + public: + virtual ~Scalar() = default; + + /** + * @brief Checks if the scalar represents a null value. + * @return true if the value is null, false otherwise. + */ + virtual bool IsNull() const = 0; + + /** + * @brief Casts the scalar to a specific derived type. + * @tparam T The target derived Scalar type. + * @return Reference to the casted value. + * @throws std::bad_cast if the cast fails. + */ + template <typename T> + const T& as() const { + auto ptr = dynamic_cast<const T*>(this); + if (!ptr) throw std::bad_cast(); + return *ptr; + } + + /** + * @brief Creates a deep copy of the scalar. + * @return A shared pointer to the cloned scalar. + */ + virtual std::shared_ptr<Scalar> clone() const = 0; + + /** + * @brief Accepts a visitor for dispatching based on scalar type. + * @param visitor The visitor to accept. + */ + virtual void accept(ScalarVisitor& visitor) const = 0; +}; + +/** + * @brief Visitor interface for Scalar, supporting type-dispatched operations. + */ +class ICEBERG_EXPORT ScalarVisitor { + public: + virtual ~ScalarVisitor() = default; + + /// Visit methods for primitive types + virtual void visit(int32_t value) = 0; + virtual void visit(int64_t value) = 0; + virtual void visit(float value) = 0; + virtual void visit(double value) = 0; + virtual void visit(bool value) = 0; + virtual void visit(const std::string& value) = 0; + + /** + * @brief Called when visiting a null scalar. + */ + virtual void visitNull() = 0; + + /// Visit methods for complex types + virtual void visitStruct(const StructScalar& value) = 0; + virtual void visitArray(const ArrayScalar& value) = 0; +}; + +/** + * @brief Represents a scalar that holds a primitive value. + * @tparam T The type of the primitive value. + */ +template <typename T> +class ICEBERG_EXPORT PrimitiveScalar : public Scalar { + public: + /** + * @brief Constructs a PrimitiveScalar from an optional value. + * @param value The optional primitive value. + */ + explicit PrimitiveScalar(std::optional<T> value) : value_(std::move(value)) {} + + bool IsNull() const override { return !value_.has_value(); } + + /** + * @brief Gets the actual value held by the scalar. + * @return Reference to the value. + * @note Behavior is undefined if the scalar is null. + */ + const T& value() const { return *value_; } + + /** + * @brief (Deprecated) Type-specific accessor for raw value. + * @tparam U Must match T. + * @return Reference to the value if types match. + * @throws std::bad_cast if U does not match T. + */ + template <typename U> + const U& as() const { + if constexpr (std::is_same_v<T, U>) return *value_; + throw std::bad_cast(); + } + + std::shared_ptr<Scalar> clone() const override { + return std::make_shared<PrimitiveScalar<T>>(value_); + } + + void accept(ScalarVisitor& visitor) const override { + if (IsNull()) { + visitor.visitNull(); + } else { + visitor.visit(*value_); + } + } + + private: + std::optional<T> value_; +}; + +// Aliases for common primitive scalar types Review Comment: We are supposed to specialize each type like `DecimalType`, `BinaryType`, etc.? -- This is an automated message from the Apache Git Service. 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