libp2p_core/transport/
optional.rs

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1// Copyright 2019 Parity Technologies (UK) Ltd.
2//
3// Permission is hereby granted, free of charge, to any person obtaining a
4// copy of this software and associated documentation files (the "Software"),
5// to deal in the Software without restriction, including without limitation
6// the rights to use, copy, modify, merge, publish, distribute, sublicense,
7// and/or sell copies of the Software, and to permit persons to whom the
8// Software is furnished to do so, subject to the following conditions:
9//
10// The above copyright notice and this permission notice shall be included in
11// all copies or substantial portions of the Software.
12//
13// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
14// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
15// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
16// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
17// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
18// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
19// DEALINGS IN THE SOFTWARE.
20
21use std::{
22    pin::Pin,
23    task::{Context, Poll},
24};
25
26use multiaddr::Multiaddr;
27
28use crate::transport::{DialOpts, ListenerId, Transport, TransportError, TransportEvent};
29
30/// Transport that is possibly disabled.
31///
32/// An `OptionalTransport<T>` is a wrapper around an `Option<T>`. If it is disabled (read: contains
33/// `None`), then any attempt to dial or listen will return `MultiaddrNotSupported`. If it is
34/// enabled (read: contains `Some`), then dialing and listening will be handled by the inner
35/// transport.
36#[derive(Debug, Copy, Clone)]
37#[pin_project::pin_project]
38pub struct OptionalTransport<T>(#[pin] Option<T>);
39
40impl<T> OptionalTransport<T> {
41    /// Builds an `OptionalTransport` with the given transport in an enabled
42    /// state.
43    pub fn some(inner: T) -> OptionalTransport<T> {
44        OptionalTransport(Some(inner))
45    }
46
47    /// Builds a disabled `OptionalTransport`.
48    pub fn none() -> OptionalTransport<T> {
49        OptionalTransport(None)
50    }
51}
52
53impl<T> From<T> for OptionalTransport<T> {
54    fn from(inner: T) -> Self {
55        OptionalTransport(Some(inner))
56    }
57}
58
59impl<T> Transport for OptionalTransport<T>
60where
61    T: Transport,
62{
63    type Output = T::Output;
64    type Error = T::Error;
65    type ListenerUpgrade = T::ListenerUpgrade;
66    type Dial = T::Dial;
67
68    fn listen_on(
69        &mut self,
70        id: ListenerId,
71        addr: Multiaddr,
72    ) -> Result<(), TransportError<Self::Error>> {
73        if let Some(inner) = self.0.as_mut() {
74            inner.listen_on(id, addr)
75        } else {
76            Err(TransportError::MultiaddrNotSupported(addr))
77        }
78    }
79
80    fn remove_listener(&mut self, id: ListenerId) -> bool {
81        if let Some(inner) = self.0.as_mut() {
82            inner.remove_listener(id)
83        } else {
84            false
85        }
86    }
87
88    fn dial(
89        &mut self,
90        addr: Multiaddr,
91        opts: DialOpts,
92    ) -> Result<Self::Dial, TransportError<Self::Error>> {
93        if let Some(inner) = self.0.as_mut() {
94            inner.dial(addr, opts)
95        } else {
96            Err(TransportError::MultiaddrNotSupported(addr))
97        }
98    }
99
100    fn poll(
101        self: Pin<&mut Self>,
102        cx: &mut Context<'_>,
103    ) -> Poll<TransportEvent<Self::ListenerUpgrade, Self::Error>> {
104        if let Some(inner) = self.project().0.as_pin_mut() {
105            inner.poll(cx)
106        } else {
107            Poll::Pending
108        }
109    }
110}
libp2p_core/transport/optional.rs

libp2p_core/transport/
optional.rs
