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
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177

//! Inter process comunication module
#![allow(clippy::missing_errors_doc)]

use std::fs::{metadata, remove_file};
use std::marker::PhantomData;
use std::net::Ipv4Addr;
use std::os::unix::net::UnixDatagram;
use std::path::{Path, PathBuf};
use std::time::Instant;

use bincode::{deserialize, serialize};
use serde::{Deserialize, Serialize};

const NAMED_SOCKET_0: &str = "gistit-0";
const NAMED_SOCKET_1: &str = "gistit-1";
const READBUF_SIZE: usize = 60_000;
const CONNECT_TIMEOUT_SECS: u64 = 3;

pub trait SockEnd {}

#[derive(Debug)]
pub struct Server;
impl SockEnd for Server {}

#[derive(Debug)]
pub struct Client;
impl SockEnd for Client {}

#[derive(Debug)]
pub struct Bridge<T: SockEnd> {
    pub sock_0: UnixDatagram,
    pub sock_1: UnixDatagram,
    base: PathBuf,
    __marker_t: PhantomData<T>,
}

/// Recv from [`NAMED_SOCKET_0`] and send to [`NAMED_SOCKET_1`]
/// The owner of sock_0
pub fn server(base: &Path) -> Result<Bridge<Server>> {
    let sockpath_0 = &base.join(NAMED_SOCKET_0);
    if metadata(sockpath_0).is_ok() {
        remove_file(sockpath_0)?;
    }

    Ok(Bridge {
        sock_0: UnixDatagram::bind(sockpath_0)?,
        sock_1: UnixDatagram::unbound()?,
        base: base.to_path_buf(),
        __marker_t: PhantomData,
    })
}

/// Recv from [`NAMED_SOCKET_1`] and send to [`NAMED_SOCKET_0`]
/// The owner of sock_1
pub fn client(base: &Path) -> Result<Bridge<Client>> {
    let sockpath_1 = &base.join(NAMED_SOCKET_1);
    if metadata(sockpath_1).is_ok() {
        remove_file(sockpath_1)?;
    }

    Ok(Bridge {
        sock_0: UnixDatagram::unbound()?,
        sock_1: UnixDatagram::bind(sockpath_1)?,
        base: base.to_path_buf(),
        __marker_t: PhantomData,
    })
}

fn __alive(base: &Path, dgram: &UnixDatagram, sock_name: &str) -> bool {
    !matches!(dgram.connect(base.join(sock_name)), Err(_))
}

fn __connect_blocking(base: &Path, dgram: &UnixDatagram, sock_name: &str) -> Result<()> {
    let earlier = Instant::now();
    while let Err(err) = dgram.connect(base.join(sock_name)) {
        if Instant::now().duration_since(earlier).as_secs() > CONNECT_TIMEOUT_SECS {
            return Err(err.into());
        }
    }
    Ok(())
}

impl Bridge<Server> {
    pub fn alive(&self) -> bool {
        __alive(&self.base, &self.sock_1, NAMED_SOCKET_1)
    }

    pub fn connect_blocking(&mut self) -> Result<()> {
        __connect_blocking(&self.base, &self.sock_1, NAMED_SOCKET_1)
    }

    pub fn send(&self, instruction: Instruction) -> Result<()> {
        let encoded = serialize(&instruction).unwrap();
        self.sock_1.send(&encoded)?;
        Ok(())
    }

    pub fn recv(&self) -> Result<Instruction> {
        let mut buf = vec![0u8; READBUF_SIZE];
        self.sock_0.recv(&mut buf)?;
        let target = deserialize(&buf).unwrap();
        Ok(target)
    }
}

impl Bridge<Client> {
    pub fn alive(&self) -> bool {
        __alive(&self.base, &self.sock_0, NAMED_SOCKET_0)
    }

    pub fn connect_blocking(&mut self) -> Result<()> {
        __connect_blocking(&self.base, &self.sock_0, NAMED_SOCKET_0)
    }

    pub fn send(&self, instruction: Instruction) -> Result<()> {
        let encoded = serialize(&instruction).unwrap();
        self.sock_0.send(&encoded)?;
        Ok(())
    }

    pub fn recv(&self) -> Result<Instruction> {
        let mut buf = vec![0u8; READBUF_SIZE];
        self.sock_1.recv(&mut buf)?;
        let target = deserialize(&buf).unwrap();
        Ok(target)
    }
}

#[derive(Serialize, Deserialize, Debug)]
pub enum Instruction {
    Listen { host: Ipv4Addr, port: u16 },
    Dial { peer_id: String },
    Provide { hash: String, data: Vec<u8> },
    Get { hash: String },
    Status,
    Shutdown,
    // Daemon responses
    Response(ServerResponse),
}

#[derive(Serialize, Deserialize, Debug)]
pub enum ServerResponse {
    PeerId(String),
    Status(String),
}

pub type Result<T> = std::result::Result<T, Error>;

#[derive(Debug)]
pub struct Error {
    pub kind: ErrorKind,
}

#[derive(Debug)]
pub enum ErrorKind {
    IO(std::io::Error),
}

impl From<std::io::Error> for Error {
    fn from(err: std::io::Error) -> Self {
        Self {
            kind: ErrorKind::IO(err),
        }
    }
}

impl std::error::Error for Error {
    fn description(&self) -> &str {
        "gistit ipc error"
    }
}

impl std::fmt::Display for Error {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "gistit ipc error")
    }
}