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

use std::{collections::TryReserveError, convert::Infallible, io, marker::PhantomData};

use async_trait::async_trait;
use cbor4ii::core::error::DecodeError;
use futures::prelude::*;
use libp2p::{
    request_response::{self, Codec},
    StreamProtocol,
};
use serde::{de::DeserializeOwned, Serialize};

/// `Behaviour` type alias for the `Cbor` codec
pub type Behaviour<Req, Resp> = request_response::Behaviour<Cbor<Req, Resp>>;

/// Forked `cbor` codec with altered request/response sizes
pub struct Cbor<Req, Resp> {
    /// Phantom data
    phantom: PhantomData<(Req, Resp)>,
    /// Maximum request size in bytes
    request_size_maximum: u64,
    /// Maximum response size in bytes
    response_size_maximum: u64,
}

impl<Req, Resp> Default for Cbor<Req, Resp> {
    fn default() -> Self {
        Cbor {
            phantom: PhantomData,
            request_size_maximum: 20 * 1024 * 1024,
            response_size_maximum: 20 * 1024 * 1024,
        }
    }
}

impl<Req, Resp> Cbor<Req, Resp> {
    /// Create a new `Cbor` codec with the given request and response sizes
    #[must_use]
    pub fn new(request_size_maximum: u64, response_size_maximum: u64) -> Self {
        Cbor {
            phantom: PhantomData,
            request_size_maximum,
            response_size_maximum,
        }
    }
}

impl<Req, Resp> Clone for Cbor<Req, Resp> {
    fn clone(&self) -> Self {
        Self::default()
    }
}

#[async_trait]
impl<Req, Resp> Codec for Cbor<Req, Resp>
where
    Req: Send + Serialize + DeserializeOwned,
    Resp: Send + Serialize + DeserializeOwned,
{
    type Protocol = StreamProtocol;
    type Request = Req;
    type Response = Resp;

    async fn read_request<T>(&mut self, _: &Self::Protocol, io: &mut T) -> io::Result<Req>
    where
        T: AsyncRead + Unpin + Send,
    {
        let mut vec = Vec::new();

        io.take(self.request_size_maximum)
            .read_to_end(&mut vec)
            .await?;

        cbor4ii::serde::from_slice(vec.as_slice()).map_err(decode_into_io_error)
    }

    async fn read_response<T>(&mut self, _: &Self::Protocol, io: &mut T) -> io::Result<Resp>
    where
        T: AsyncRead + Unpin + Send,
    {
        let mut vec = Vec::new();

        io.take(self.response_size_maximum)
            .read_to_end(&mut vec)
            .await?;

        cbor4ii::serde::from_slice(vec.as_slice()).map_err(decode_into_io_error)
    }

    async fn write_request<T>(
        &mut self,
        _: &Self::Protocol,
        io: &mut T,
        req: Self::Request,
    ) -> io::Result<()>
    where
        T: AsyncWrite + Unpin + Send,
    {
        let data: Vec<u8> =
            cbor4ii::serde::to_vec(Vec::new(), &req).map_err(encode_into_io_error)?;

        io.write_all(data.as_ref()).await?;

        Ok(())
    }

    async fn write_response<T>(
        &mut self,
        _: &Self::Protocol,
        io: &mut T,
        resp: Self::Response,
    ) -> io::Result<()>
    where
        T: AsyncWrite + Unpin + Send,
    {
        let data: Vec<u8> =
            cbor4ii::serde::to_vec(Vec::new(), &resp).map_err(encode_into_io_error)?;

        io.write_all(data.as_ref()).await?;

        Ok(())
    }
}

/// Convert a `cbor4ii::serde::DecodeError` into an `io::Error`
fn decode_into_io_error(err: cbor4ii::serde::DecodeError<Infallible>) -> io::Error {
    match err {
        cbor4ii::serde::DecodeError::Core(DecodeError::Read(e)) => {
            io::Error::new(io::ErrorKind::Other, e)
        }
        cbor4ii::serde::DecodeError::Core(e @ DecodeError::Unsupported { .. }) => {
            io::Error::new(io::ErrorKind::Unsupported, e)
        }
        cbor4ii::serde::DecodeError::Core(e @ DecodeError::Eof { .. }) => {
            io::Error::new(io::ErrorKind::UnexpectedEof, e)
        }
        cbor4ii::serde::DecodeError::Core(e) => io::Error::new(io::ErrorKind::InvalidData, e),
        cbor4ii::serde::DecodeError::Custom(e) => {
            io::Error::new(io::ErrorKind::Other, e.to_string())
        }
    }
}

/// Convert a `cbor4ii::serde::EncodeError` into an `io::Error`
fn encode_into_io_error(err: cbor4ii::serde::EncodeError<TryReserveError>) -> io::Error {
    io::Error::new(io::ErrorKind::Other, err)
}