fn setup_state()

in glean-core/src/lib.rs [229:252]

• 24 lines of code
• 6 McCabe index (conditional complexity)

fn setup_state(state: State) {
    // The `OnceCell` type wrapping our state is thread-safe and can only be set once.
    // Therefore even if our check for it being empty succeeds, setting it could fail if a
    // concurrent thread is quicker in setting it.
    // However this will not cause a bigger problem, as the second `set` operation will just fail.
    // We can log it and move on.
    //
    // For all wrappers this is not a problem, as the State object is intialized exactly once on
    // calling `initialize` on the global singleton and further operations check that it has been
    // initialized.
    if STATE.get().is_none() {
        if STATE.set(Mutex::new(state)).is_err() {
            log::error!(
                "Global Glean state object is initialized already. This probably happened concurrently."
            );
        }
    } else {
        // We allow overriding the global State object to support test mode.
        // In test mode the State object is fully destroyed and recreated.
        // This all happens behind a mutex and is therefore also thread-safe.
        let mut lock = STATE.get().unwrap().lock().unwrap();
        *lock = state;
    }
}