rust-libp2p/core/src/upgrade/denied.rs

// Copyright 2017-2018 Parity Technologies (UK) Ltd.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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use crate::upgrade::{InboundUpgrade, OutboundUpgrade, UpgradeInfo};
use futures::future;
use std::iter;
use void::Void;

/// Dummy implementation of `UpgradeInfo`/`InboundUpgrade`/`OutboundUpgrade` that doesn't support
/// any protocol.
#[derive(Debug, Copy, Clone)]
pub struct DeniedUpgrade;

impl UpgradeInfo for DeniedUpgrade {
    type Info = &'static str;
    type InfoIter = iter::Empty<Self::Info>;

    fn protocol_info(&self) -> Self::InfoIter {
        iter::empty()
    }
}

impl<C> InboundUpgrade<C> for DeniedUpgrade {
    type Output = Void;
    type Error = Void;
    type Future = future::Pending<Result<Self::Output, Self::Error>>;

    fn upgrade_inbound(self, _: C, _: Self::Info) -> Self::Future {
        future::pending()
    }
}

impl<C> OutboundUpgrade<C> for DeniedUpgrade {
    type Output = Void;
    type Error = Void;
    type Future = future::Pending<Result<Self::Output, Self::Error>>;

    fn upgrade_outbound(self, _: C, _: Self::Info) -> Self::Future {
        future::pending()
    }
}