dearxan 0.5.5

Static analyzer and patcher for the Arxan anti-debug/DRM as found in FromSoftware titles
Documentation 
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use std::{any::Any, fmt, panic::UnwindSafe};

pub type DearxanResult = std::result::Result<Status, Error>;

/// The informational part of a [`DearxanResult`].
#[derive(Clone, Debug)]
pub struct Status {
    /// Whether Arxan was applied to the program.
    pub is_arxan_detected: bool,
    /// If true, the callback execution is blocking the program entry point. If false, the callback
    /// is being executed in a separate thread.
    ///
    /// In either case, it is guaranteed that the Arxan entry point stub has finished initializing
    /// once the callback runs.
    pub is_executing_entrypoint: bool,
}

/// Errors that prevented dearxan from finishing.
///
/// Either a `dyn`[`std::error::Error`] error or a payload panic as a string.
#[derive(Debug)]
pub enum Error {
    Error(Box<dyn std::error::Error + Send + Sync>),
    Panic(String),
}

impl Error {
    pub(crate) fn from_panic_payload(payload: Box<dyn Any + Send + 'static>) -> Self {
        // As of Rust 2024, library panic payloads are always `&'static str`.
        match payload.downcast::<&'static str>() {
            Ok(panic_msg) => Self::Panic(panic_msg.to_string()),
            Err(_) => Self::Panic("panicked, but failed to retrieve panic message".to_owned()),
        }
    }
}

pub(crate) fn from_maybe_panic<T, E>(
    fun: impl FnOnce() -> Result<T, E> + UnwindSafe,
) -> Result<T, Error>
where
    E: Into<Box<dyn std::error::Error + Send + Sync>>,
{
    std::panic::catch_unwind(fun)
        .map(|res| res.map_err(|e| Error::Error(e.into())))
        .unwrap_or_else(|e| Err(Error::from_panic_payload(e)))
}

impl fmt::Display for Error {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            Self::Error(err) => err.fmt(f),
            Self::Panic(msg) => f.write_str(msg),
        }
    }
}

impl std::error::Error for Error {}