// Copyright 2026 Google LLC

//

// Licensed 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.

//

////////////////////////////////////////////////////////////////////////////////

#ifndef SHIM_STDPLUS_FD_HPP

#define SHIM_STDPLUS_FD_HPP

#include <span>

#include <cstddef>

#include <string>

#include <cstdint>

#include <linux/fs.h>

#include <stdexcept>

// Reopen boost::container to add the missing alias if needed

namespace boost {

namespace container {

using out_of_range = std::out_of_range;

}

}

namespace stdplus {

namespace fd {

enum class OpenAccess {

    ReadOnly,

    WriteOnly,

    ReadWrite

};

struct OpenFlags {

    OpenAccess access;

    OpenFlags(OpenAccess a) : access(a) {}

};

class Fd {

public:

    virtual ~Fd() = default;

    virtual std::span<const std::byte> write(std::span<const std::byte> data) = 0;

    virtual std::span<std::byte> read(std::span<std::byte> buf) = 0;

    virtual int ioctl(unsigned long request, void* data) = 0;

};

class ManagedFd : public Fd {

public:

    ManagedFd() = default;

    ManagedFd(ManagedFd&&) = default;

    ManagedFd& operator=(ManagedFd&&) = default;

    std::span<const std::byte> write(std::span<const std::byte> data) override { return data; }

    std::span<std::byte> read(std::span<std::byte> buf) override { 

        return buf; 

    }

    int ioctl(unsigned long request, void* data) override {

        if (request == BLKGETSIZE64) {

            *reinterpret_cast<uint64_t*>(data) = 1024 * 1024; // 1MB dummy size

        }

        return 0;

    }

    int get() const { return 0; }

};

inline ManagedFd open(const std::string&, OpenAccess) {

    return ManagedFd();

}

inline ManagedFd open(const std::string&, OpenFlags) {

    return ManagedFd();

}

inline ManagedFd open(const char*, OpenFlags) {

    return ManagedFd();

}

} // namespace fd

} // namespace stdplus

#endif