SchemaValidator.h

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/*
 * MIT License
 *
 * Copyright (c) 2026 nfx
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

 
#pragma once
 
#include "Document.h"
 
#include <optional>
#include <string>
#include <string_view>
#include <unordered_map>
#include <vector>
 
namespace nfx::json
{
    //=====================================================================
    // ValidationError class
    //=====================================================================

    class ValidationError final
    {
    public:
        struct ErrorEntry
        {
            std::string path;               
            std::string message;            
            std::string constraint;         
            std::string expectedValue = {}; 
            std::string actualValue = {};   
        };
 
    public:
        //----------------------------------------------
        // Construction
        //----------------------------------------------
        explicit ValidationError( const ErrorEntry& entry );

        ValidationError(
            std::string path,
            std::string message,
            std::string constraint,
            std::string expectedValue = {},
            std::string actualValue = {} );
 
        //----------------------------------------------
        // Destruction
        //----------------------------------------------

        ~ValidationError() = default;
 
        //----------------------------------------------
        // Accessors
        //----------------------------------------------

        inline const std::string& path() const noexcept;

        inline const std::string& message() const noexcept;

        inline const std::string& constraint() const noexcept;

        inline const std::string& expectedValue() const noexcept;

        inline const std::string& actualValue() const noexcept;

        std::string toString() const;
 
    private:
        ErrorEntry m_error;
    };
 
    //=====================================================================
    // ValidationResult class
    //=====================================================================

    class ValidationResult final
    {
    public:
        //----------------------------------------------
        // Construction
        //----------------------------------------------

        ValidationResult() = default;

        explicit ValidationResult( std::vector<ValidationError> errors );
 
        //----------------------------------------------
        // Destruction
        //----------------------------------------------

        ~ValidationResult() = default;
 
        //----------------------------------------------
        // Status checking
        //----------------------------------------------

        inline bool isValid() const noexcept;

        inline bool hasErrors() const noexcept;

        inline size_t errorCount() const noexcept;
 
        //----------------------------------------------
        // Error access
        //----------------------------------------------

        inline const std::vector<ValidationError>& errors() const noexcept;

        const ValidationError& error( size_t index ) const;

        std::string errorSummary() const;
 
        //----------------------------------------------
        // Error manipulation
        //----------------------------------------------

        void addError( const ValidationError::ErrorEntry& entry );

        void addError( const ValidationError& error );

        void addError(
            std::string_view path,
            std::string_view message,
            std::string_view constraint,
            std::string_view expectedValue = {},
            std::string_view actualValue = {} );
 
    private:
        std::vector<ValidationError> m_errors;
    };
 
    //=====================================================================
    // SchemaDraft enumeration
    //=====================================================================

    enum class SchemaDraft
    {
        Unknown,     
        Draft04,     
        Draft06,     
        Draft07,     
        Draft201909, 
        Draft202012  
    };
 
    //=====================================================================
    // SchemaValidator class
    //=====================================================================

    class SchemaValidator final
    {
    public:
        //----------------------------------------------
        // Options
        //----------------------------------------------

        struct Options
        {
            bool strictMode = false; 
            size_t maxDepth = 64;    
        };
 
        //----------------------------------------------
        // Construction
        //----------------------------------------------

        SchemaValidator();

        explicit SchemaValidator( const Document& schema );

        SchemaValidator( const Document& schema, const Options& options );

        SchemaValidator( const SchemaValidator& other );

        SchemaValidator( SchemaValidator&& other ) noexcept;
 
        //----------------------------------------------
        // Destruction
        //----------------------------------------------

        ~SchemaValidator();
 
        //----------------------------------------------
        // Assignment
        //----------------------------------------------

        SchemaValidator& operator=( const SchemaValidator& other );

        SchemaValidator& operator=( SchemaValidator&& other ) noexcept;
 
        //----------------------------------------------
        // Schema management
        //----------------------------------------------

        bool load( const Document& schema );

        bool load( std::string_view schemaJson );

        bool hasSchema() const;

        void clear();

        Document schema() const;
 
        //----------------------------------------------
        // Validation operations
        //----------------------------------------------

        ValidationResult validate( const Document& document ) const;

        ValidationResult validateAtPath(
            const Document& document, std::string_view documentPath = "", std::string_view schemaPath = "" ) const;
 
        //----------------------------------------------
        // Schema information
        //----------------------------------------------

        std::string version() const;

        SchemaDraft draft() const;

        std::string draftString() const;

        std::string title() const;

        std::string description() const;

        const Options& options() const noexcept;
 
    private:
        //----------------------------------------------
        // Internal validation methods
        //----------------------------------------------

        void validateNode(
            const Document& document,
            const Document& schema,
            std::string_view path,
            ValidationResult& result,
            size_t currentDepth = 0 ) const;
 
        void validateType(
            const Document& document, const Document& schema, std::string_view path, ValidationResult& result ) const;
 
        void validateRequired(
            const Document& document, const Document& schema, std::string_view path, ValidationResult& result ) const;
 
        void validateProperties(
            const Document& document,
            const Document& schema,
            std::string_view path,
            ValidationResult& result,
            size_t currentDepth = 0 ) const;
 
        void validateNumericConstraints(
            const Document& document, const Document& schema, std::string_view path, ValidationResult& result ) const;
 
        void validateStringConstraints(
            const Document& document, const Document& schema, std::string_view path, ValidationResult& result ) const;
 
        void validateEnum(
            const Document& document, const Document& schema, std::string_view path, ValidationResult& result ) const;
 
        void validateConst(
            const Document& document, const Document& schema, std::string_view path, ValidationResult& result ) const;
 
        void validateAdditionalProperties(
            const Document& document, const Document& schema, std::string_view path, ValidationResult& result ) const;
 
        void validateObject(
            const Document& document,
            const Document& schema,
            std::string_view path,
            ValidationResult& result,
            size_t currentDepth = 0 ) const;
 
        void validateArray(
            const Document& document,
            const Document& schema,
            std::string_view path,
            ValidationResult& result,
            size_t currentDepth = 0 ) const;
 
        void validateAllOf(
            const Document& document,
            const Document& schema,
            std::string_view path,
            ValidationResult& result,
            size_t currentDepth = 0 ) const;
 
        void validateAnyOf(
            const Document& document,
            const Document& schema,
            std::string_view path,
            ValidationResult& result,
            size_t currentDepth = 0 ) const;
 
        void validateOneOf(
            const Document& document,
            const Document& schema,
            std::string_view path,
            ValidationResult& result,
            size_t currentDepth = 0 ) const;
 
        void validateNot(
            const Document& document,
            const Document& schema,
            std::string_view path,
            ValidationResult& result,
            size_t currentDepth = 0 ) const;
 
        void validateIfThenElse(
            const Document& document,
            const Document& schema,
            std::string_view path,
            ValidationResult& result,
            size_t currentDepth = 0 ) const;
 
        //----------------------------------------------
        // Helper methods
        //----------------------------------------------
 
        bool referenceExists( std::string_view reference ) const noexcept;
        Document resolveReference( std::string_view reference ) const;
        std::string actualType( const Document& document, std::string_view path ) const noexcept;
        Document extractSubDocument( const Document& sourceDocument, std::string_view path ) const;
        void buildAnchorIndex();
        void scanForAnchors( const Document& schema, const std::string& currentPath );
        void detectDraft();
        std::string draftToString() const noexcept;
 
        //----------------------------------------------
        // Member variables
        //----------------------------------------------
 
        static constexpr size_t DEFAULT_MAX_DEPTH = 64;
 
        Document m_schema;                                            
        bool m_schemaLoaded = false;                                  
        bool m_strictMode = false;                                    
        size_t m_maxDepth = DEFAULT_MAX_DEPTH;                        
        SchemaDraft m_schemaDraft = SchemaDraft::Unknown;             
        mutable std::unordered_map<std::string, Document> m_refCache; 
        std::unordered_map<std::string, std::string> m_anchorIndex;   
    };
} // namespace nfx::json
 
#include "detail/SchemaValidator.inl"