Extends the `?` operator to Option types by Wrap the Option to Error

option_to_error.rs

pub trait Sealed {}

impl<T> Sealed for Option<T> {}

pub trait Context<T, E>: Sealed {
    /// Wrap the Option to a general error.
    fn ok(self) -> Result<T, Error>;

    /// Wrap the Option with additional message
    fn err<C>(self, context: C) -> Result<T, Error>
    where
        C: Display + Send + Sync + 'static;

    /// Wrap the Option::None with additional message that is evaluated lazily
    /// only once with Option::unwrap().
    fn with_err<C, F>(self, f: F) -> Result<T, Error>
    where
        C: Display + Send + Sync + 'static,
        F: FnOnce() -> C;
}

impl<T> Context<T, Infallible> for Option<T> {
    fn ok(self) -> Result<T, Error> {
        self.ok_or(MessageCode::GENERAL_ERROR.into())
    }

    fn err<C>(self, context: C) -> Result<T, Error>
    where
        C: Display + Send + Sync + 'static,
    {
        self.ok_or(Error::msg(context))
    }

    fn with_err<C, F>(self, context: F) -> Result<T, Error>
    where
        C: Display + Send + Sync + 'static,
        F: FnOnce() -> C,
    {
        self.ok_or_else(|| Error::msg(context()))
    }
}