tor/src/rust/protover/errors.rs

// Copyright (c) 2018, The Tor Project, Inc.
// Copyright (c) 2018, isis agora lovecruft
// See LICENSE for licensing information

//! Various errors which may occur during protocol version parsing.

use std::fmt;
use std::fmt::Display;

/// All errors which may occur during protover parsing routines.
#[derive(Clone, Copy, Debug, Eq, PartialEq, Hash)]
#[allow(missing_docs)] // See Display impl for error descriptions
pub enum ProtoverError {
    Overlap,
    LowGreaterThanHigh,
    Unparseable,
    ExceedsMax,
    ExceedsExpansionLimit,
    UnknownProtocol,
    ExceedsNameLimit,
    InvalidProtocol,
}

/// Descriptive error messages for `ProtoverError` variants.
impl Display for ProtoverError {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match *self {
            ProtoverError::Overlap
                => write!(f, "Two or more (low, high) protover ranges would overlap once expanded."),
            ProtoverError::LowGreaterThanHigh
                => write!(f, "The low in a (low, high) protover range was greater than high."),
            ProtoverError::Unparseable
                => write!(f, "The protover string was unparseable."),
            ProtoverError::ExceedsMax
                => write!(f, "The high in a (low, high) protover range exceeds u32::MAX."),
            ProtoverError::ExceedsExpansionLimit
                => write!(f, "The protover string would exceed the maximum expansion limit."),
            ProtoverError::UnknownProtocol
                => write!(f, "A protocol in the protover string we attempted to parse is unknown."),
            ProtoverError::ExceedsNameLimit
                => write!(f, "An unrecognised protocol name was too long."),
            ProtoverError::InvalidProtocol
                => write!(f, "A protocol name includes invalid characters."),
        }
    }
}