dspk-stream 0.0.10

//! Errors of a stream session.

use std::fmt;

/// What went wrong in a stream session.
#[derive(Debug, thiserror::Error)]
pub enum StreamError {
    #[error("I/O: {0}")]
    Io(#[from] std::io::Error),
    #[error("TLS: {0}")]
    Tls(String),
    #[error("connect: {0}")]
    Connect(#[from] quinn::ConnectError),
    #[error("connection: {0}")]
    Connection(#[from] quinn::ConnectionError),
    #[error("read: {0}")]
    Read(#[from] quinn::ReadExactError),
    #[error("write: {0}")]
    Write(#[from] quinn::WriteError),
    #[error("message of {len} bytes exceeds the {max}-byte limit")]
    TooLarge { len: usize, max: usize },
    #[error("stream ended inside a message")]
    Truncated,
    #[error("decode: {0}")]
    Decode(#[from] prost::DecodeError),
    /// The peer sent something the protocol does not allow.
    #[error("protocol: {0}")]
    Protocol(String),
    /// The server refused or failed a request, and said why.
    #[error("server: {0}")]
    Server(String),
    #[error(transparent)]
    Dsp(#[from] dspk_core::DspError),
}

impl StreamError {
    pub(crate) fn protocol(message: impl fmt::Display) -> Self {
        Self::Protocol(message.to_string())
    }

    /// What to tell a client about this error (the reason, without the kind's prefix).
    pub(crate) fn reason(&self) -> String {
        match self {
            Self::Protocol(m) | Self::Server(m) | Self::Tls(m) => m.clone(),
            other => other.to_string(),
        }
    }

    /// The peer closed the connection (a client leaving), not a failure.
    pub fn is_closed_by_peer(&self) -> bool {
        use quinn::{ConnectionError, ReadError, ReadExactError};
        matches!(
            self,
            Self::Connection(ConnectionError::ApplicationClosed(_) | ConnectionError::LocallyClosed)
                | Self::Read(ReadExactError::ReadError(ReadError::ConnectionLost(ConnectionError::ApplicationClosed(_) | ConnectionError::LocallyClosed)))
        )
    }
}

pub type StreamResult<T> = Result<T, StreamError>;