wasm-tokio 0.5.0

Streaming WebAssembly codec based on Tokio
Documentation 
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use ::core::future::Future;

use tokio::io::{AsyncRead, AsyncReadExt as _, AsyncWrite, AsyncWriteExt as _};
use tokio_util::{
    bytes::{BufMut as _, BytesMut},
    codec::{Decoder, Encoder},
};

pub trait AsyncReadValue: AsyncRead {
    #[cfg_attr(
        feature = "tracing",
        tracing::instrument(level = "trace", ret, skip_all, fields(ty = "bool"))
    )]
    fn read_bool(&mut self) -> impl Future<Output = std::io::Result<bool>>
    where
        Self: Unpin,
    {
        async move {
            match self.read_u8().await? {
                0 => Ok(false),
                1 => Ok(true),
                n => Err(std::io::Error::new(
                    std::io::ErrorKind::InvalidData,
                    format!("invalid bool value byte `{n}`"),
                )),
            }
        }
    }

    #[cfg_attr(
        feature = "tracing",
        tracing::instrument(level = "trace", ret, skip_all, fields(ty = "option"))
    )]
    fn read_option_status(&mut self) -> impl Future<Output = std::io::Result<bool>>
    where
        Self: Unpin,
    {
        async move {
            match self.read_u8().await? {
                0 => Ok(false),
                1 => Ok(true),
                n => Err(std::io::Error::new(
                    std::io::ErrorKind::InvalidData,
                    format!("invalid option status byte value `{n}`"),
                )),
            }
        }
    }

    #[cfg_attr(
        feature = "tracing",
        tracing::instrument(level = "trace", ret, skip_all, fields(ty = "result"))
    )]
    fn read_result_status(&mut self) -> impl Future<Output = std::io::Result<bool>>
    where
        Self: Unpin,
    {
        async move {
            match self.read_u8().await? {
                0 => Ok(true),
                1 => Ok(false),
                n => Err(std::io::Error::new(
                    std::io::ErrorKind::InvalidData,
                    format!("invalid result status byte value `{n}`"),
                )),
            }
        }
    }
}

impl<T: AsyncRead> AsyncReadValue for T {}

pub trait AsyncWriteValue: AsyncWrite {
    #[cfg_attr(
        feature = "tracing",
        tracing::instrument(level = "trace", ret, skip_all, fields(ty = "bool"))
    )]
    fn write_bool(&mut self, v: bool) -> impl Future<Output = std::io::Result<()>>
    where
        Self: Unpin,
    {
        async move { self.write_u8(v.into()).await }
    }

    #[cfg_attr(
        feature = "tracing",
        tracing::instrument(level = "trace", ret, skip_all, fields(ty = "option"))
    )]
    fn write_option_status<T>(&mut self, v: Option<T>) -> impl Future<Output = std::io::Result<()>>
    where
        Self: Unpin,
    {
        async move { self.write_u8(v.is_some().into()).await }
    }

    #[cfg_attr(
        feature = "tracing",
        tracing::instrument(level = "trace", ret, skip_all, fields(ty = "result"))
    )]
    fn write_result_status<T, E>(
        &mut self,
        v: Result<T, E>,
    ) -> impl Future<Output = std::io::Result<()>>
    where
        Self: Unpin,
    {
        async move { self.write_u8(v.is_err().into()).await }
    }
}

impl<T: AsyncWrite> AsyncWriteValue for T {}

pub struct BoolCodec;

impl Encoder<bool> for BoolCodec {
    type Error = std::io::Error;

    fn encode(&mut self, item: bool, dst: &mut BytesMut) -> Result<(), Self::Error> {
        dst.put_u8(item.into());
        Ok(())
    }
}

impl Decoder for BoolCodec {
    type Item = bool;
    type Error = std::io::Error;

    fn decode(&mut self, src: &mut BytesMut) -> Result<Option<Self::Item>, Self::Error> {
        let Some(v) = src.first() else { return Ok(None) };
        match *v {
            0 => Ok(Some(false)),
            1 => Ok(Some(true)),
            n => Err(std::io::Error::new(
                std::io::ErrorKind::InvalidData,
                format!("invalid bool value byte `{n}`"),
            )),
        }
    }
}