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
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158

use socks5_proto::{Address, Reply, Response};
use std::{
    io::{IoSlice, Result},
    net::SocketAddr,
    pin::Pin,
    task::{Context, Poll},
};
use tokio::{
    io::{AsyncRead, AsyncWrite, AsyncWriteExt, ReadBuf},
    net::{
        tcp::{ReadHalf, WriteHalf},
        TcpStream,
    },
};

#[derive(Debug)]
pub struct Bind<S> {
    stream: TcpStream,
    _state: S,
}

#[derive(Debug)]
pub struct NeedFirstReply;

#[derive(Debug)]
pub struct NeedSecondReply;

#[derive(Debug)]
pub struct Ready;

impl Bind<NeedFirstReply> {
    pub(super) fn new(stream: TcpStream) -> Self {
        Self {
            stream,
            _state: NeedFirstReply,
        }
    }

    pub async fn reply(mut self, reply: Reply, addr: Address) -> Result<Bind<NeedSecondReply>> {
        let resp = Response::new(reply, addr);
        resp.write_to(&mut self.stream).await?;
        Ok(Bind::<NeedSecondReply>::new(self.stream))
    }

    #[inline]
    pub fn local_addr(&self) -> Result<SocketAddr> {
        self.stream.local_addr()
    }

    #[inline]
    pub fn peer_addr(&self) -> Result<SocketAddr> {
        self.stream.peer_addr()
    }

    #[inline]
    pub async fn shutdown(&mut self) -> Result<()> {
        self.stream.shutdown().await
    }
}

impl Bind<NeedSecondReply> {
    fn new(stream: TcpStream) -> Self {
        Self {
            stream,
            _state: NeedSecondReply,
        }
    }

    pub async fn reply(mut self, reply: Reply, addr: Address) -> Result<Bind<Ready>> {
        let resp = Response::new(reply, addr);
        resp.write_to(&mut self.stream).await?;
        Ok(Bind::<Ready>::new(self.stream))
    }

    #[inline]
    pub fn local_addr(&self) -> Result<SocketAddr> {
        self.stream.local_addr()
    }

    #[inline]
    pub fn peer_addr(&self) -> Result<SocketAddr> {
        self.stream.peer_addr()
    }

    #[inline]
    pub async fn shutdown(&mut self) -> Result<()> {
        self.stream.shutdown().await
    }
}

impl Bind<Ready> {
    fn new(stream: TcpStream) -> Self {
        Self {
            stream,
            _state: Ready,
        }
    }

    #[inline]
    pub fn local_addr(&self) -> Result<SocketAddr> {
        self.stream.local_addr()
    }

    #[inline]
    pub fn peer_addr(&self) -> Result<SocketAddr> {
        self.stream.peer_addr()
    }

    #[inline]
    pub fn split(&mut self) -> (ReadHalf, WriteHalf) {
        self.stream.split()
    }
}

impl AsyncRead for Bind<Ready> {
    fn poll_read(
        mut self: Pin<&mut Self>,
        cx: &mut Context<'_>,
        buf: &mut ReadBuf<'_>,
    ) -> Poll<Result<()>> {
        Pin::new(&mut self.stream).poll_read(cx, buf)
    }
}

impl AsyncWrite for Bind<Ready> {
    #[inline]
    fn poll_write(
        mut self: Pin<&mut Self>,
        cx: &mut Context<'_>,
        buf: &[u8],
    ) -> Poll<Result<usize>> {
        Pin::new(&mut self.stream).poll_write(cx, buf)
    }

    #[inline]
    fn poll_write_vectored(
        mut self: Pin<&mut Self>,
        cx: &mut Context<'_>,
        bufs: &[IoSlice<'_>],
    ) -> Poll<Result<usize>> {
        Pin::new(&mut self.stream).poll_write_vectored(cx, bufs)
    }

    #[inline]
    fn is_write_vectored(&self) -> bool {
        self.stream.is_write_vectored()
    }

    #[inline]
    fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>> {
        Pin::new(&mut self.stream).poll_flush(cx)
    }

    #[inline]
    fn poll_shutdown(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>> {
        Pin::new(&mut self.stream).poll_shutdown(cx)
    }
}