Class GenericSchemaDocument


#include <include/rapidjson/schema.h>

template <typename ValueT, typename Allocator = CrtAllocator>
class GenericSchemaDocument


JSON schema document.

A JSON schema document is a compiled version of a JSON schema. It is basically a tree of internal::Schema.

This is an immutable class (i.e. its instance cannot be modified after construction).
Template Parameters

ValueT - Type of JSON value (e.g. Value ), which also determine the encoding.

Allocator - Allocator type for allocating memory of this document.

Mentioned in


GetRootGet the root schema.


Lines 1579-1816 in include/rapidjson/schema.h.

template <typename ValueT, typename Allocator = CrtAllocator>
class GenericSchemaDocument {
    typedef ValueT ValueType;
    typedef IGenericRemoteSchemaDocumentProvider<GenericSchemaDocument> IRemoteSchemaDocumentProviderType;
    typedef Allocator AllocatorType;
    typedef typename ValueType::EncodingType EncodingType;
    typedef typename EncodingType::Ch Ch;
    typedef internal::Schema<GenericSchemaDocument> SchemaType;
    typedef GenericPointer<ValueType, Allocator> PointerType;
    typedef GenericValue<EncodingType, Allocator> URIType;
    friend class internal::Schema<GenericSchemaDocument>;
    template <typename, typename, typename>
    friend class GenericSchemaValidator;

    //! Constructor.
        Compile a JSON document into schema document.

        \param document A JSON document as source.
        \param uri The base URI of this schema document for purposes of violation reporting.
        \param uriLength Length of \c name, in code points.
        \param remoteProvider An optional remote schema document provider for resolving remote reference. Can be null.
        \param allocator An optional allocator instance for allocating memory. Can be null.
    explicit GenericSchemaDocument(const ValueType& document, const Ch* uri = 0, SizeType uriLength = 0,
        IRemoteSchemaDocumentProviderType* remoteProvider = 0, Allocator* allocator = 0) :
        schemaMap_(allocator, kInitialSchemaMapSize),
        schemaRef_(allocator, kInitialSchemaRefSize)
        if (!allocator_)
            ownAllocator_ = allocator_ = RAPIDJSON_NEW(Allocator)();

        Ch noUri[1] = {0};
        uri_.SetString(uri ? uri : noUri, uriLength, *allocator_);

        typeless_ = static_cast<SchemaType*>(allocator_->Malloc(sizeof(SchemaType)));
        new (typeless_) SchemaType(this, PointerType(), ValueType(kObjectType).Move(), ValueType(kObjectType).Move(), allocator_);

        // Generate root schema, it will call CreateSchema() to create sub-schemas,
        // And call AddRefSchema() if there are $ref.
        CreateSchemaRecursive(&root_, PointerType(), document, document);

        // Resolve $ref
        while (!schemaRef_.Empty()) {
            SchemaRefEntry* refEntry = schemaRef_.template Pop<SchemaRefEntry>(1);
            if (const SchemaType* s = GetSchema(refEntry->target)) {
                if (refEntry->schema)
                    *refEntry->schema = s;

                // Create entry in map if not exist
                if (!GetSchema(refEntry->source)) {
                    new (schemaMap_.template Push<SchemaEntry>()) SchemaEntry(refEntry->source, const_cast<SchemaType*>(s), false, allocator_);
            else if (refEntry->schema)
                *refEntry->schema = typeless_;


        RAPIDJSON_ASSERT(root_ != 0);

        schemaRef_.ShrinkToFit(); // Deallocate all memory for ref

    //! Move constructor in C++11
    GenericSchemaDocument(GenericSchemaDocument&& rhs) RAPIDJSON_NOEXCEPT :
        rhs.remoteProvider_ = 0;
        rhs.allocator_ = 0;
        rhs.ownAllocator_ = 0;
        rhs.typeless_ = 0;

    //! Destructor
    ~GenericSchemaDocument() {
        while (!schemaMap_.Empty())
            schemaMap_.template Pop<SchemaEntry>(1)->~SchemaEntry();

        if (typeless_) {


    const URIType& GetURI() const { return uri_; }

    //! Get the root schema.
    const SchemaType& GetRoot() const { return *root_; }

    //! Prohibit copying
    GenericSchemaDocument(const GenericSchemaDocument&);
    //! Prohibit assignment
    GenericSchemaDocument& operator=(const GenericSchemaDocument&);

    struct SchemaRefEntry {
        SchemaRefEntry(const PointerType& s, const PointerType& t, const SchemaType** outSchema, Allocator *allocator) : source(s, allocator), target(t, allocator), schema(outSchema) {}
        PointerType source;
        PointerType target;
        const SchemaType** schema;

    struct SchemaEntry {
        SchemaEntry(const PointerType& p, SchemaType* s, bool o, Allocator* allocator) : pointer(p, allocator), schema(s), owned(o) {}
        ~SchemaEntry() {
            if (owned) {
        PointerType pointer;
        SchemaType* schema;
        bool owned;

    void CreateSchemaRecursive(const SchemaType** schema, const PointerType& pointer, const ValueType& v, const ValueType& document) {
        if (schema)
            *schema = typeless_;

        if (v.GetType() == kObjectType) {
            const SchemaType* s = GetSchema(pointer);
            if (!s)
                CreateSchema(schema, pointer, v, document);

            for (typename ValueType::ConstMemberIterator itr = v.MemberBegin(); itr != v.MemberEnd(); ++itr)
                CreateSchemaRecursive(0, pointer.Append(itr->name, allocator_), itr->value, document);
        else if (v.GetType() == kArrayType)
            for (SizeType i = 0; i < v.Size(); i++)
                CreateSchemaRecursive(0, pointer.Append(i, allocator_), v[i], document);

    void CreateSchema(const SchemaType** schema, const PointerType& pointer, const ValueType& v, const ValueType& document) {
        if (v.IsObject()) {
            if (!HandleRefSchema(pointer, schema, v, document)) {
                SchemaType* s = new (allocator_->Malloc(sizeof(SchemaType))) SchemaType(this, pointer, v, document, allocator_);
                new (schemaMap_.template Push<SchemaEntry>()) SchemaEntry(pointer, s, true, allocator_);
                if (schema)
                    *schema = s;

    bool HandleRefSchema(const PointerType& source, const SchemaType** schema, const ValueType& v, const ValueType& document) {
        static const Ch kRefString[] = { '$', 'r', 'e', 'f', '\0' };
        static const ValueType kRefValue(kRefString, 4);

        typename ValueType::ConstMemberIterator itr = v.FindMember(kRefValue);
        if (itr == v.MemberEnd())
            return false;

        if (itr->value.IsString()) {
            SizeType len = itr->value.GetStringLength();
            if (len > 0) {
                const Ch* s = itr->value.GetString();
                SizeType i = 0;
                while (i < len && s[i] != '#') // Find the first #

                if (i > 0) { // Remote reference, resolve immediately
                    if (remoteProvider_) {
                        if (const GenericSchemaDocument* remoteDocument = remoteProvider_->GetRemoteDocument(s, i)) {
                            PointerType pointer(&s[i], len - i, allocator_);
                            if (pointer.IsValid()) {
                                if (const SchemaType* sc = remoteDocument->GetSchema(pointer)) {
                                    if (schema)
                                        *schema = sc;
                                    new (schemaMap_.template Push<SchemaEntry>()) SchemaEntry(source, const_cast<SchemaType*>(sc), false, allocator_);
                                    return true;
                else if (s[i] == '#') { // Local reference, defer resolution
                    PointerType pointer(&s[i], len - i, allocator_);
                    if (pointer.IsValid()) {
                        if (const ValueType* nv = pointer.Get(document))
                            if (HandleRefSchema(source, schema, *nv, document))
                                return true;

                        new (schemaRef_.template Push<SchemaRefEntry>()) SchemaRefEntry(source, pointer, schema, allocator_);
                        return true;
        return false;

    const SchemaType* GetSchema(const PointerType& pointer) const {
        for (const SchemaEntry* target = schemaMap_.template Bottom<SchemaEntry>(); target != schemaMap_.template End<SchemaEntry>(); ++target)
            if (pointer == target->pointer)
                return target->schema;
        return 0;

    PointerType GetPointer(const SchemaType* schema) const {
        for (const SchemaEntry* target = schemaMap_.template Bottom<SchemaEntry>(); target != schemaMap_.template End<SchemaEntry>(); ++target)
            if (schema == target->schema)
                return target->pointer;
        return PointerType();

    const SchemaType* GetTypeless() const { return typeless_; }

    static const size_t kInitialSchemaMapSize = 64;
    static const size_t kInitialSchemaRefSize = 64;

    IRemoteSchemaDocumentProviderType* remoteProvider_;
    Allocator *allocator_;
    Allocator *ownAllocator_;
    const SchemaType* root_;                //!< Root schema.
    SchemaType* typeless_;
    internal::Stack<Allocator> schemaMap_;  // Stores created Pointer -> Schemas
    internal::Stack<Allocator> schemaRef_;  // Stores Pointer from $ref and schema which holds the $ref
    URIType uri_;

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