wgtmac commented on code in PR #347:
URL: https://github.com/apache/iceberg-cpp/pull/347#discussion_r2567765219
##########
src/iceberg/util/type_util.h:
##########
@@ -20,52 +20,117 @@
#pragma once
#include <functional>
-#include <stack>
+#include <memory>
+#include <string>
+#include <string_view>
+#include <unordered_map>
+#include <unordered_set>
+#include <vector>
-#include "iceberg/type.h"
+#include "iceberg/iceberg_export.h"
+#include "iceberg/result.h"
+#include "iceberg/schema_field.h"
+#include "iceberg/type_fwd.h"
+#include "iceberg/util/formatter_internal.h"
+#include "iceberg/util/string_util.h"
/// \file iceberg/util/type_util.h
-/// Utility functions for Iceberg types.
+/// Utility functions and visitors for Iceberg types.
namespace iceberg {
+/// \brief Visitor for building a map from field ID to SchemaField reference.
+class IdToFieldVisitor {
+ public:
+ explicit IdToFieldVisitor(
+ std::unordered_map<int32_t, std::reference_wrapper<const SchemaField>>&
+ id_to_field);
+ Status Visit(const PrimitiveType& type);
+ Status Visit(const NestedType& type);
+
+ private:
+ std::unordered_map<int32_t, std::reference_wrapper<const SchemaField>>&
id_to_field_;
+};
+
+/// \brief Visitor for building a map from field name to field ID.
+class NameToIdVisitor {
+ public:
+ explicit NameToIdVisitor(
+ std::unordered_map<std::string, int32_t, StringHash, std::equal_to<>>&
name_to_id,
+ bool case_sensitive = true,
+ std::function<std::string(std::string_view)> quoting_func = {});
+ Status Visit(const ListType& type, const std::string& path,
+ const std::string& short_path);
+ Status Visit(const MapType& type, const std::string& path,
+ const std::string& short_path);
+ Status Visit(const StructType& type, const std::string& path,
+ const std::string& short_path);
+ Status Visit(const PrimitiveType& type, const std::string& path,
+ const std::string& short_path);
+ void Finish();
+
+ private:
+ std::string BuildPath(std::string_view prefix, std::string_view field_name,
+ bool case_sensitive);
+
+ private:
+ bool case_sensitive_;
+ std::unordered_map<std::string, int32_t, StringHash, std::equal_to<>>&
name_to_id_;
+ std::unordered_map<std::string, int32_t, StringHash, std::equal_to<>>
short_name_to_id_;
+ std::function<std::string(std::string_view)> quoting_func_;
+};
+
+/// \brief Visitor for building a map from field ID to position path.
+class PositionPathVisitor {
+ public:
+ Status Visit(const PrimitiveType& type);
+ Status Visit(const StructType& type);
+ Status Visit(const ListType& type);
+ Status Visit(const MapType& type);
+ std::unordered_map<int32_t, std::vector<size_t>> Finish();
+
+ private:
+ constexpr static int32_t kUnassignedFieldId = -1;
+ int32_t current_field_id_ = kUnassignedFieldId;
+ std::vector<size_t> current_path_;
+ std::unordered_map<int32_t, std::vector<size_t>> position_path_;
+};
+
+/// \brief Visitor for pruning columns based on selected field IDs.
+///
+/// This visitor traverses a schema and creates a projected version containing
only
+/// the specified fields. When `select_full_types` is true, a field with all
its
+/// sub-fields are selected if its field-id has been selected; otherwise, only
leaf
+/// fields of selected field-ids are selected.
+///
+/// \note It returns an error when projection is not successful.
+class PruneColumnVisitor {
+ public:
+ PruneColumnVisitor(const std::unordered_set<int32_t>& selected_ids,
+ bool select_full_types);
+
+ Result<std::shared_ptr<Type>> Visit(const std::shared_ptr<Type>& type) const;
+ Result<std::shared_ptr<Type>> Visit(const SchemaField& field) const;
+ static SchemaField MakeField(const SchemaField& field, std::shared_ptr<Type>
type);
+ Result<std::shared_ptr<Type>> Visit(const std::shared_ptr<StructType>& type)
const;
+ Result<std::shared_ptr<Type>> Visit(const std::shared_ptr<ListType>& type)
const;
+ Result<std::shared_ptr<Type>> Visit(const std::shared_ptr<MapType>& type)
const;
+
+ private:
+ const std::unordered_set<int32_t>& selected_ids_;
+ const bool select_full_types_;
+};
+
/// \brief Index parent field IDs for all fields in a struct hierarchy.
+/// Corresponds to Java's indexParents(Types.StructType struct).
/// \param root_struct The root struct type to analyze
/// \return A map from field ID to its parent struct field ID
/// \note This function assumes the input StructType has already been
validated:
/// - All field IDs must be non-negative
/// - All field IDs must be unique across the entire schema hierarchy
/// If the struct is part of a Schema, these invariants are enforced by
/// StructType::InitFieldById which checks for duplicate field IDs.
-static std::unordered_map<int32_t, int32_t> indexParents(const StructType&
root_struct) {
- std::unordered_map<int32_t, int32_t> id_to_parent;
- std::stack<int32_t> parent_id_stack;
-
- // Recursive function to visit and build parent relationships
- std::function<void(const Type&)> visit = [&](const Type& type) -> void {
- switch (type.type_id()) {
- case TypeId::kStruct:
- case TypeId::kList:
- case TypeId::kMap: {
- const auto& nested_type = static_cast<const NestedType&>(type);
- for (const auto& field : nested_type.fields()) {
- if (!parent_id_stack.empty()) {
- id_to_parent[field.field_id()] = parent_id_stack.top();
- }
- parent_id_stack.push(field.field_id());
- visit(*field.type());
- parent_id_stack.pop();
- }
- break;
- }
-
- default:
- break;
- }
- };
-
- visit(root_struct);
- return id_to_parent;
-}
+ICEBERG_EXPORT std::unordered_map<int32_t, int32_t> indexParents(
Review Comment:
```suggestion
ICEBERG_EXPORT std::unordered_map<int32_t, int32_t> IndexParents(
```
##########
src/iceberg/util/type_util.h:
##########
@@ -20,52 +20,117 @@
#pragma once
#include <functional>
-#include <stack>
+#include <memory>
+#include <string>
+#include <string_view>
+#include <unordered_map>
+#include <unordered_set>
+#include <vector>
-#include "iceberg/type.h"
+#include "iceberg/iceberg_export.h"
+#include "iceberg/result.h"
+#include "iceberg/schema_field.h"
+#include "iceberg/type_fwd.h"
+#include "iceberg/util/formatter_internal.h"
+#include "iceberg/util/string_util.h"
/// \file iceberg/util/type_util.h
-/// Utility functions for Iceberg types.
+/// Utility functions and visitors for Iceberg types.
namespace iceberg {
+/// \brief Visitor for building a map from field ID to SchemaField reference.
+class IdToFieldVisitor {
+ public:
+ explicit IdToFieldVisitor(
+ std::unordered_map<int32_t, std::reference_wrapper<const SchemaField>>&
+ id_to_field);
+ Status Visit(const PrimitiveType& type);
+ Status Visit(const NestedType& type);
+
+ private:
+ std::unordered_map<int32_t, std::reference_wrapper<const SchemaField>>&
id_to_field_;
+};
+
+/// \brief Visitor for building a map from field name to field ID.
+class NameToIdVisitor {
+ public:
+ explicit NameToIdVisitor(
+ std::unordered_map<std::string, int32_t, StringHash, std::equal_to<>>&
name_to_id,
+ bool case_sensitive = true,
+ std::function<std::string(std::string_view)> quoting_func = {});
+ Status Visit(const ListType& type, const std::string& path,
+ const std::string& short_path);
+ Status Visit(const MapType& type, const std::string& path,
+ const std::string& short_path);
+ Status Visit(const StructType& type, const std::string& path,
+ const std::string& short_path);
+ Status Visit(const PrimitiveType& type, const std::string& path,
+ const std::string& short_path);
+ void Finish();
+
+ private:
+ std::string BuildPath(std::string_view prefix, std::string_view field_name,
+ bool case_sensitive);
+
+ private:
+ bool case_sensitive_;
+ std::unordered_map<std::string, int32_t, StringHash, std::equal_to<>>&
name_to_id_;
+ std::unordered_map<std::string, int32_t, StringHash, std::equal_to<>>
short_name_to_id_;
+ std::function<std::string(std::string_view)> quoting_func_;
+};
+
+/// \brief Visitor for building a map from field ID to position path.
+class PositionPathVisitor {
+ public:
+ Status Visit(const PrimitiveType& type);
+ Status Visit(const StructType& type);
+ Status Visit(const ListType& type);
+ Status Visit(const MapType& type);
+ std::unordered_map<int32_t, std::vector<size_t>> Finish();
+
+ private:
+ constexpr static int32_t kUnassignedFieldId = -1;
+ int32_t current_field_id_ = kUnassignedFieldId;
+ std::vector<size_t> current_path_;
+ std::unordered_map<int32_t, std::vector<size_t>> position_path_;
+};
+
+/// \brief Visitor for pruning columns based on selected field IDs.
+///
+/// This visitor traverses a schema and creates a projected version containing
only
+/// the specified fields. When `select_full_types` is true, a field with all
its
+/// sub-fields are selected if its field-id has been selected; otherwise, only
leaf
+/// fields of selected field-ids are selected.
+///
+/// \note It returns an error when projection is not successful.
+class PruneColumnVisitor {
+ public:
+ PruneColumnVisitor(const std::unordered_set<int32_t>& selected_ids,
+ bool select_full_types);
+
+ Result<std::shared_ptr<Type>> Visit(const std::shared_ptr<Type>& type) const;
+ Result<std::shared_ptr<Type>> Visit(const SchemaField& field) const;
+ static SchemaField MakeField(const SchemaField& field, std::shared_ptr<Type>
type);
+ Result<std::shared_ptr<Type>> Visit(const std::shared_ptr<StructType>& type)
const;
+ Result<std::shared_ptr<Type>> Visit(const std::shared_ptr<ListType>& type)
const;
+ Result<std::shared_ptr<Type>> Visit(const std::shared_ptr<MapType>& type)
const;
+
+ private:
+ const std::unordered_set<int32_t>& selected_ids_;
+ const bool select_full_types_;
+};
+
/// \brief Index parent field IDs for all fields in a struct hierarchy.
+/// Corresponds to Java's indexParents(Types.StructType struct).
Review Comment:
```suggestion
```
We don't need this.
##########
src/iceberg/util/type_util.h:
##########
@@ -20,52 +20,117 @@
#pragma once
#include <functional>
-#include <stack>
+#include <memory>
+#include <string>
+#include <string_view>
+#include <unordered_map>
+#include <unordered_set>
+#include <vector>
-#include "iceberg/type.h"
+#include "iceberg/iceberg_export.h"
+#include "iceberg/result.h"
+#include "iceberg/schema_field.h"
+#include "iceberg/type_fwd.h"
+#include "iceberg/util/formatter_internal.h"
Review Comment:
```suggestion
```
We cannot include internal header here.
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