zesdex/crates/zesdex-utils/src/error.rs

#![allow(
    clippy::cast_possible_truncation,
    clippy::cast_sign_loss,
    clippy::cast_precision_loss,
    clippy::cast_possible_wrap
)]

use std::fmt;

/// Unified error type for the zesdex codebase.
#[derive(Debug)]
pub enum Error {
    /// Wraps an I/O error.
    Io(std::io::Error),
    /// Wraps a JSON serialization/deserialization error.
    Serde(serde_json::Error),
    /// A generic parse failure with a message.
    Parse(String),
    /// A resource was not found.
    NotFound(String),
    /// Invalid input was provided.
    InvalidInput(String),
    /// The session is locked and cannot be accessed.
    SessionLocked,
}

impl fmt::Display for Error {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            Self::Io(e) => write!(f, "I/O error: {e}"),
            Self::Serde(e) => write!(f, "serialization error: {e}"),
            Self::Parse(msg) => write!(f, "parse error: {msg}"),
            Self::NotFound(resource) => write!(f, "not found: {resource}"),
            Self::InvalidInput(msg) => write!(f, "invalid input: {msg}"),
            Self::SessionLocked => write!(f, "session is locked"),
        }
    }
}

impl std::error::Error for Error {
    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
        match self {
            Self::Io(e) => Some(e),
            Self::Serde(e) => Some(e),
            Self::Parse(_) | Self::NotFound(_) | Self::InvalidInput(_) | Self::SessionLocked => {
                None
            }
        }
    }
}

// ---------------------------------------------------------------------------
// From conversions
// ---------------------------------------------------------------------------

impl From<std::io::Error> for Error {
    fn from(e: std::io::Error) -> Self {
        Self::Io(e)
    }
}

impl From<serde_json::Error> for Error {
    fn from(e: serde_json::Error) -> Self {
        Self::Serde(e)
    }
}

// Note: anyhow already provides `From<E> for anyhow::Error` for all
// `E: std::error::Error + Send + Sync + 'static`, which our `Error` satisfies.

// ---------------------------------------------------------------------------
// Type alias
// ---------------------------------------------------------------------------

/// Convenience alias for `Result<T, zesdex_utils::Error>`.
pub type Result<T> = std::result::Result<T, Error>;

// ---------------------------------------------------------------------------
// Additional impls
// ---------------------------------------------------------------------------

impl Error {
    /// Create a `Parse` error.
    pub fn parse(msg: impl Into<String>) -> Self {
        Self::Parse(msg.into())
    }

    /// Create a `NotFound` error.
    pub fn not_found(resource: impl Into<String>) -> Self {
        Self::NotFound(resource.into())
    }

    /// Create an `InvalidInput` error.
    pub fn invalid_input(msg: impl Into<String>) -> Self {
        Self::InvalidInput(msg.into())
    }
}