transmission/libtransmission/dns.h

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// This file Copyright 2022 Mnemosyne LLC.
// It may be used under GPLv2 (SPDX: GPL-2.0-only), GPLv3 (SPDX: GPL-3.0-only),
// or any future license endorsed by Mnemosyne LLC.
// License text can be found in the licenses/ folder.
#pragma once
#include <functional>
#include <string_view>
#include "transmission.h"
#include "net.h"
namespace libtransmission
{
class Dns
{
public:
virtual ~Dns() = default;
using Callback = std::function<void(struct sockaddr const*, socklen_t salen, time_t expires_at)>;
using Tag = unsigned int;
class Hints
{
public:
Hints()
{
}
int ai_family = AF_UNSPEC;
int ai_socktype = SOCK_DGRAM;
int ai_protocol = IPPROTO_UDP;
[[nodiscard]] constexpr int compare(Hints const& that) const noexcept // <=>
{
if (ai_family != that.ai_family)
{
return ai_family < that.ai_family ? -1 : 1;
}
if (ai_socktype != that.ai_socktype)
{
return ai_socktype < that.ai_socktype ? -1 : 1;
}
if (ai_protocol != that.ai_protocol)
{
return ai_protocol < that.ai_protocol ? -1 : 1;
}
return 0;
}
[[nodiscard]] constexpr bool operator<(Hints const& that) const noexcept
{
return compare(that) < 0;
}
};
[[nodiscard]] virtual std::optional<std::pair<struct sockaddr const*, socklen_t>> cached(
std::string_view address,
Hints hints = {}) const = 0;
virtual Tag lookup(std::string_view address, Callback&& callback, Hints hints = {}) = 0;
virtual void cancel(Tag) = 0;
};
} // namespace libtransmission