1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134

// Copyright 2021 COMIT Network.
//
// 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
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.

use crate::codec::{Cookie, Message, NewRegistration, RendezvousCodec};
use crate::handler::Error;
use crate::handler::PROTOCOL_IDENT;
use crate::substream_handler::{FutureSubstream, Next, PassthroughProtocol, SubstreamHandler};
use crate::{ErrorCode, Namespace, Registration, Ttl};
use asynchronous_codec::Framed;
use futures::{SinkExt, TryFutureExt, TryStreamExt};
use libp2p_swarm::{NegotiatedSubstream, SubstreamProtocol};
use std::task::Context;
use void::Void;

pub struct Stream(FutureSubstream<OutEvent, Error>);

impl SubstreamHandler for Stream {
    type InEvent = Void;
    type OutEvent = OutEvent;
    type Error = Error;
    type OpenInfo = OpenInfo;

    fn upgrade(
        open_info: Self::OpenInfo,
    ) -> SubstreamProtocol<PassthroughProtocol, Self::OpenInfo> {
        SubstreamProtocol::new(PassthroughProtocol::new(PROTOCOL_IDENT), open_info)
    }

    fn new(substream: NegotiatedSubstream, info: Self::OpenInfo) -> Self {
        let mut stream = Framed::new(substream, RendezvousCodec::default());
        let sent_message = match info {
            OpenInfo::RegisterRequest(new_registration) => Message::Register(new_registration),
            OpenInfo::UnregisterRequest(namespace) => Message::Unregister(namespace),
            OpenInfo::DiscoverRequest {
                namespace,
                cookie,
                limit,
            } => Message::Discover {
                namespace,
                cookie,
                limit,
            },
        };

        Self(FutureSubstream::new(async move {
            use Message::*;
            use OutEvent::*;

            stream
                .send(sent_message.clone())
                .map_err(Error::WriteMessage)
                .await?;
            let received_message = stream.try_next().map_err(Error::ReadMessage).await?;
            let received_message = received_message.ok_or(Error::UnexpectedEndOfStream)?;

            let event = match (sent_message, received_message) {
                (Register(registration), RegisterResponse(Ok(ttl))) => Registered {
                    namespace: registration.namespace,
                    ttl,
                },
                (Register(registration), RegisterResponse(Err(error))) => {
                    RegisterFailed(registration.namespace, error)
                }
                (Discover { .. }, DiscoverResponse(Ok((registrations, cookie)))) => Discovered {
                    registrations,
                    cookie,
                },
                (Discover { namespace, .. }, DiscoverResponse(Err(error))) => {
                    DiscoverFailed { namespace, error }
                }
                (.., other) => return Err(Error::BadMessage(other)),
            };

            stream.close().map_err(Error::WriteMessage).await?;

            Ok(event)
        }))
    }

    fn inject_event(self, event: Self::InEvent) -> Self {
        void::unreachable(event)
    }

    fn advance(self, cx: &mut Context<'_>) -> Result<Next<Self, Self::OutEvent>, Self::Error> {
        Ok(self.0.advance(cx)?.map_state(Stream))
    }
}

#[derive(Debug, Clone)]
pub enum OutEvent {
    Registered {
        namespace: Namespace,
        ttl: Ttl,
    },
    RegisterFailed(Namespace, ErrorCode),
    Discovered {
        registrations: Vec<Registration>,
        cookie: Cookie,
    },
    DiscoverFailed {
        namespace: Option<Namespace>,
        error: ErrorCode,
    },
}

#[allow(clippy::large_enum_variant)]
#[allow(clippy::enum_variant_names)]
#[derive(Debug)]
pub enum OpenInfo {
    RegisterRequest(NewRegistration),
    UnregisterRequest(Namespace),
    DiscoverRequest {
        namespace: Option<Namespace>,
        cookie: Option<Cookie>,
        limit: Option<Ttl>,
    },
}