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

mod tcp;
pub use tcp::*;

#[cfg(unix)]
mod unix;

#[cfg(unix)]
pub use unix::*;

#[cfg(windows)]
mod windows;

use std::time::Duration;
use std::{convert, io};

use async_trait::async_trait;
use distant_auth::AuthHandler;
#[cfg(windows)]
pub use windows::*;

use super::ClientConfig;
use crate::client::{Client, UntypedClient};
use crate::common::{Connection, Transport};

/// Interface that performs the connection to produce a [`Transport`] for use by the [`Client`].
#[async_trait]
pub trait Connector {
    /// Type of transport produced by the connection.
    type Transport: Transport + 'static;

    async fn connect(self) -> io::Result<Self::Transport>;
}

#[async_trait]
impl<T: Transport + 'static> Connector for T {
    type Transport = T;

    async fn connect(self) -> io::Result<Self::Transport> {
        Ok(self)
    }
}

/// Builder for a [`Client`] or [`UntypedClient`].
pub struct ClientBuilder<H, C> {
    auth_handler: H,
    connector: C,
    config: ClientConfig,
    connect_timeout: Option<Duration>,
}

impl<H, C> ClientBuilder<H, C> {
    /// Configure the authentication handler to use when connecting to a server.
    pub fn auth_handler<U>(self, auth_handler: U) -> ClientBuilder<U, C> {
        ClientBuilder {
            auth_handler,
            config: self.config,
            connector: self.connector,
            connect_timeout: self.connect_timeout,
        }
    }

    /// Configure the client-local configuration details.
    pub fn config(self, config: ClientConfig) -> Self {
        Self {
            auth_handler: self.auth_handler,
            config,
            connector: self.connector,
            connect_timeout: self.connect_timeout,
        }
    }

    /// Configure the connector to use to facilitate connecting to a server.
    pub fn connector<U>(self, connector: U) -> ClientBuilder<H, U> {
        ClientBuilder {
            auth_handler: self.auth_handler,
            config: self.config,
            connector,
            connect_timeout: self.connect_timeout,
        }
    }

    /// Configure a maximum duration to wait for a connection to a server to complete.
    pub fn connect_timeout(self, connect_timeout: impl Into<Option<Duration>>) -> Self {
        Self {
            auth_handler: self.auth_handler,
            config: self.config,
            connector: self.connector,
            connect_timeout: connect_timeout.into(),
        }
    }
}

impl ClientBuilder<(), ()> {
    pub fn new() -> Self {
        Self {
            auth_handler: (),
            config: Default::default(),
            connector: (),
            connect_timeout: None,
        }
    }
}

impl Default for ClientBuilder<(), ()> {
    fn default() -> Self {
        Self::new()
    }
}

impl<H, C> ClientBuilder<H, C>
where
    H: AuthHandler + Send,
    C: Connector,
{
    /// Establishes a connection with a remote server using the configured [`Transport`]
    /// and other settings, returning a new [`UntypedClient`] instance once the connection
    /// is fully established and authenticated.
    pub async fn connect_untyped(self) -> io::Result<UntypedClient> {
        let auth_handler = self.auth_handler;
        let config = self.config;
        let connect_timeout = self.connect_timeout;

        let f = async move {
            let transport = match connect_timeout {
                Some(duration) => tokio::time::timeout(duration, self.connector.connect())
                    .await
                    .map_err(|x| io::Error::new(io::ErrorKind::TimedOut, x))
                    .and_then(convert::identity)?,
                None => self.connector.connect().await?,
            };
            let connection = Connection::client(transport, auth_handler).await?;
            Ok(UntypedClient::spawn(connection, config))
        };

        match connect_timeout {
            Some(duration) => tokio::time::timeout(duration, f)
                .await
                .map_err(|x| io::Error::new(io::ErrorKind::TimedOut, x))
                .and_then(convert::identity),
            None => f.await,
        }
    }

    /// Establishes a connection with a remote server using the configured [`Transport`] and other
    /// settings, returning a new [`Client`] instance once the connection is fully established and
    /// authenticated.
    pub async fn connect<T, U>(self) -> io::Result<Client<T, U>> {
        Ok(self.connect_untyped().await?.into_typed_client())
    }
}