libp2p-core 0.43.2

// Copyright 2022 Protocol Labs.
// 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
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.

use std::{convert::Infallible, iter};

use futures::future;

use crate::upgrade::{InboundUpgrade, OutboundUpgrade, UpgradeInfo};

/// Implementation of [`UpgradeInfo`], [`InboundUpgrade`] and [`OutboundUpgrade`] that always
/// returns a pending upgrade.
#[derive(Debug, Copy, Clone)]
pub struct PendingUpgrade<P> {
    protocol_name: P,
}

impl<P> PendingUpgrade<P> {
    pub fn new(protocol_name: P) -> Self {
        Self { protocol_name }
    }
}

impl<P> UpgradeInfo for PendingUpgrade<P>
where
    P: AsRef<str> + Clone,
{
    type Info = P;
    type InfoIter = iter::Once<P>;

    fn protocol_info(&self) -> Self::InfoIter {
        iter::once(self.protocol_name.clone())
    }
}

impl<C, P> InboundUpgrade<C> for PendingUpgrade<P>
where
    P: AsRef<str> + Clone,
{
    type Output = Infallible;
    type Error = Infallible;
    type Future = future::Pending<Result<Self::Output, Self::Error>>;

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

impl<C, P> OutboundUpgrade<C> for PendingUpgrade<P>
where
    P: AsRef<str> + Clone,
{
    type Output = Infallible;
    type Error = Infallible;
    type Future = future::Pending<Result<Self::Output, Self::Error>>;

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