// 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 <cstddef>

#include <memory>

#include "core/string_ref.h"

#include "util/variant/variant_value.h"

namespace doris {

// Validate a complete metadata dictionary, including every UTF-8 key. Call this once before

// validating one or more payloads that reference the same dictionary.

void validate_variant_metadata(VariantMetadataRef metadata);

// Validate exactly one recursive Variant payload. The referenced metadata must already have

// passed validate_variant_metadata().

void validate_variant_payload(VariantValueRef value);

// Owns one encoded Variant row. The byte layout is

// [u32 little-endian metadata_size][metadata][exactly one value].

class VariantField {

public:

    VariantField() noexcept = default;

    ~VariantField() = default;

    VariantField(const VariantField& other);

    VariantField(VariantField&& other) noexcept;

    VariantField& operator=(const VariantField& other);

    VariantField& operator=(VariantField&& other) noexcept;

    // Both entry points validate the complete row once, then own a byte-for-byte copy;

    // decode never borrows the input buffer.

    static VariantField encode(VariantValueRef value);

    static VariantField decode(StringRef bytes);

    // The returned view borrows this field and is invalidated by assignment or destruction. It is

    // O(1) and does not revalidate. Default and moved-from fields have empty bytes(), and ref()

    // throws for them.

    VariantValueRef ref() const;

    StringRef bytes() const noexcept;

    // VariantField has no ordering or equality contract; all six comparisons always throw.

    bool operator<(const VariantField&) const;

    bool operator<=(const VariantField&) const;

    bool operator==(const VariantField&) const;

    bool operator!=(const VariantField&) const;

    bool operator>=(const VariantField&) const;

    bool operator>(const VariantField&) const;

private:

    VariantField(std::unique_ptr<char[]> data, size_t size) noexcept;

    void swap(VariantField& other) noexcept;

    std::unique_ptr<char[]> _data;

    size_t _size = 0;

};

} // namespace doris