/*

 * Copyright (c) 2021, Ali Mohammad Pur <mpfard@serenityos.org>

 * Copyright (c) 2023, Tim Schumacher <timschumi@gmx.de>

 *

 * SPDX-License-Identifier: BSD-2-Clause

 */

#include <AK/ConstrainedStream.h>

namespace AK {

ConstrainedStream::ConstrainedStream(MaybeOwned<Stream> stream, u64 limit)

    : m_stream(move(stream))

    , m_limit(limit)

{

}

ErrorOr<Bytes> ConstrainedStream::read_some(Bytes bytes)

{

    if (bytes.size() >= m_limit)

        bytes = bytes.trim(m_limit);

    auto result = TRY(m_stream->read_some(bytes));

    m_limit -= result.size();

    return result;

}

ErrorOr<void> ConstrainedStream::discard(size_t discarded_bytes)

{

    if (discarded_bytes > m_limit)

        return Error::from_string_literal("Trying to discard more bytes than allowed");

    // Note: This will remove more bytes from the limit than intended if a failing discard yields partial results.

    //       However, stopping early is most likely better than running over the end of the stream.

    m_limit -= discarded_bytes;

    TRY(m_stream->discard(discarded_bytes));

    return {};

}

ErrorOr<size_t> ConstrainedStream::write_some(ReadonlyBytes)

{

    return Error::from_errno(EBADF);

}

bool ConstrainedStream::is_eof() const

{

    return m_limit == 0 || m_stream->is_eof();

}

bool ConstrainedStream::is_open() const

{

    return m_stream->is_open();

}

void ConstrainedStream::close()

{

}

}