ferogram-fsm 0.3.8

// Copyright (c) Ankit Chaubey <ankitchaubey.dev@gmail.com>
//
// ferogram: async Telegram MTProto client in Rust
// https://github.com/ankit-chaubey/ferogram
//
// Licensed under either the MIT License or the Apache License 2.0.
// See the LICENSE-MIT or LICENSE-APACHE file in this repository:
// https://github.com/ankit-chaubey/ferogram
//
// Feel free to use, modify, and share this code.
// Please keep this notice when redistributing.

use std::fmt;

/// An error from a [`StateStorage`](crate::StateStorage) backend.
#[derive(Debug)]
pub struct StorageError {
    message: String,
    source: Option<Box<dyn std::error::Error + Send + Sync>>,
}

impl StorageError {
    /// Create a storage error with a plain message.
    pub fn new(message: impl Into<String>) -> Self {
        Self {
            message: message.into(),
            source: None,
        }
    }

    /// Create a storage error wrapping an underlying cause.
    pub fn with_source(
        message: impl Into<String>,
        source: impl std::error::Error + Send + Sync + 'static,
    ) -> Self {
        Self {
            message: message.into(),
            source: Some(Box::new(source)),
        }
    }
}

impl fmt::Display for StorageError {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "state storage error: {}", self.message)?;
        if let Some(ref src) = self.source {
            write!(f, ": {src}")?;
        }
        Ok(())
    }
}

impl std::error::Error for StorageError {
    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
        self.source.as_ref().map(|e| e.as_ref() as _)
    }
}