should be it

external/duckdb/extension/json/include/json_structure.hpp

@@ -0,0 +1,94 @@
+//===----------------------------------------------------------------------===//
+//                         DuckDB
+//
+// json_structure.hpp
+//
+//
+//===----------------------------------------------------------------------===//
+
+#pragma once
+
+#include "json_common.hpp"
+
+namespace duckdb {
+
+struct JSONStructureDescription;
+struct DateFormatMap;
+struct StrpTimeFormat;
+class MutableDateFormatMap;
+
+struct JSONStructureNode {
+public:
+	JSONStructureNode();
+	JSONStructureNode(const char *key_ptr, const size_t key_len);
+	JSONStructureNode(yyjson_val *key_p, yyjson_val *val_p, bool ignore_errors);
+
+	//! Disable copy constructors
+	JSONStructureNode(const JSONStructureNode &other) = delete;
+	JSONStructureNode &operator=(const JSONStructureNode &) = delete;
+	//! Enable move constructors
+	JSONStructureNode(JSONStructureNode &&other) noexcept;
+	JSONStructureNode &operator=(JSONStructureNode &&) noexcept;
+
+	JSONStructureDescription &GetOrCreateDescription(LogicalTypeId type);
+
+	bool ContainsVarchar() const;
+	void InitializeCandidateTypes(idx_t max_depth, bool convert_strings_to_integers, idx_t depth = 0);
+	void RefineCandidateTypes(yyjson_val *vals[], idx_t val_count, Vector &string_vector, ArenaAllocator &allocator,
+	                          MutableDateFormatMap &date_format_map);
+
+private:
+	void RefineCandidateTypesArray(yyjson_val *vals[], idx_t val_count, Vector &string_vector,
+	                               ArenaAllocator &allocator, MutableDateFormatMap &date_format_map);
+	void RefineCandidateTypesObject(yyjson_val *vals[], idx_t val_count, Vector &string_vector,
+	                                ArenaAllocator &allocator, MutableDateFormatMap &date_format_map);
+	void RefineCandidateTypesString(yyjson_val *vals[], idx_t val_count, Vector &string_vector,
+	                                MutableDateFormatMap &date_format_map);
+	void EliminateCandidateTypes(idx_t vec_count, Vector &string_vector, MutableDateFormatMap &date_format_map);
+	bool EliminateCandidateFormats(idx_t vec_count, Vector &string_vector, const Vector &result_vector,
+	                               MutableDateFormatMap &date_format_map);
+
+public:
+	unique_ptr<string> key;
+	bool initialized = false;
+	vector<JSONStructureDescription> descriptions;
+	idx_t count;
+	idx_t null_count;
+};
+
+struct JSONStructureDescription {
+public:
+	explicit JSONStructureDescription(LogicalTypeId type_p);
+	//! Disable copy constructors
+	JSONStructureDescription(const JSONStructureDescription &other) = delete;
+	JSONStructureDescription &operator=(const JSONStructureDescription &) = delete;
+	//! Enable move constructors
+	JSONStructureDescription(JSONStructureDescription &&other) noexcept;
+	JSONStructureDescription &operator=(JSONStructureDescription &&) noexcept;
+
+	JSONStructureNode &GetOrCreateChild();
+	JSONStructureNode &GetOrCreateChild(const char *key_ptr, size_t key_size);
+	JSONStructureNode &GetOrCreateChild(yyjson_val *key, yyjson_val *val, bool ignore_errors);
+
+public:
+	//! Type of this description
+	LogicalTypeId type = LogicalTypeId::INVALID;
+
+	//! Map to children and children
+	json_key_map_t<idx_t> key_map;
+	vector<JSONStructureNode> children;
+
+	//! Candidate types (if auto-detecting and type == LogicalTypeId::VARCHAR)
+	vector<LogicalTypeId> candidate_types;
+};
+
+struct JSONStructure {
+public:
+	static void ExtractStructure(yyjson_val *val, JSONStructureNode &node, bool ignore_errors);
+	static void MergeNodes(JSONStructureNode &merged, const JSONStructureNode &node);
+	static LogicalType StructureToType(ClientContext &context, const JSONStructureNode &node, idx_t max_depth,
+	                                   double field_appearance_threshold, idx_t map_inference_threshold,
+	                                   idx_t depth = 0, const LogicalType &null_type = LogicalType::JSON());
+};
+
+} // namespace duckdb