libp2p_core/transport/
optional.rs

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 crate::transport::{ListenerId, Transport, TransportError, TransportEvent};
22use multiaddr::Multiaddr;
23use std::{pin::Pin, task::Context, task::Poll};
24
25/// Transport that is possibly disabled.
26///
27/// An `OptionalTransport<T>` is a wrapper around an `Option<T>`. If it is disabled (read: contains
28/// `None`), then any attempt to dial or listen will return `MultiaddrNotSupported`. If it is
29/// enabled (read: contains `Some`), then dialing and listening will be handled by the inner
30/// transport.
31#[derive(Debug, Copy, Clone)]
32#[pin_project::pin_project]
33pub struct OptionalTransport<T>(#[pin] Option<T>);
34
35impl<T> OptionalTransport<T> {
36    /// Builds an `OptionalTransport` with the given transport in an enabled
37    /// state.
38    pub fn some(inner: T) -> OptionalTransport<T> {
39        OptionalTransport(Some(inner))
40    }
41
42    /// Builds a disabled `OptionalTransport`.
43    pub fn none() -> OptionalTransport<T> {
44        OptionalTransport(None)
45    }
46}
47
48impl<T> From<T> for OptionalTransport<T> {
49    fn from(inner: T) -> Self {
50        OptionalTransport(Some(inner))
51    }
52}
53
54impl<T> Transport for OptionalTransport<T>
55where
56    T: Transport,
57{
58    type Output = T::Output;
59    type Error = T::Error;
60    type ListenerUpgrade = T::ListenerUpgrade;
61    type Dial = T::Dial;
62
63    fn listen_on(
64        &mut self,
65        id: ListenerId,
66        addr: Multiaddr,
67    ) -> Result<(), TransportError<Self::Error>> {
68        if let Some(inner) = self.0.as_mut() {
69            inner.listen_on(id, addr)
70        } else {
71            Err(TransportError::MultiaddrNotSupported(addr))
72        }
73    }
74
75    fn remove_listener(&mut self, id: ListenerId) -> bool {
76        if let Some(inner) = self.0.as_mut() {
77            inner.remove_listener(id)
78        } else {
79            false
80        }
81    }
82
83    fn dial(&mut self, addr: Multiaddr) -> Result<Self::Dial, TransportError<Self::Error>> {
84        if let Some(inner) = self.0.as_mut() {
85            inner.dial(addr)
86        } else {
87            Err(TransportError::MultiaddrNotSupported(addr))
88        }
89    }
90
91    fn dial_as_listener(
92        &mut self,
93        addr: Multiaddr,
94    ) -> Result<Self::Dial, TransportError<Self::Error>> {
95        if let Some(inner) = self.0.as_mut() {
96            inner.dial_as_listener(addr)
97        } else {
98            Err(TransportError::MultiaddrNotSupported(addr))
99        }
100    }
101
102    fn address_translation(&self, server: &Multiaddr, observed: &Multiaddr) -> Option<Multiaddr> {
103        if let Some(inner) = &self.0 {
104            inner.address_translation(server, observed)
105        } else {
106            None
107        }
108    }
109
110    fn poll(
111        self: Pin<&mut Self>,
112        cx: &mut Context<'_>,
113    ) -> Poll<TransportEvent<Self::ListenerUpgrade, Self::Error>> {
114        if let Some(inner) = self.project().0.as_pin_mut() {
115            inner.poll(cx)
116        } else {
117            Poll::Pending
118        }
119    }
120}
libp2p_core/transport/optional.rs

libp2p_core/transport/
optional.rs
