Shared via Rust Playground

playground.rs

use std::sync::Once;

pub struct Lazy<T: Sync>(pub *const T, pub Once);

impl<T: Sync> Lazy<T> {
    #[inline(always)]
    pub fn get<F>(&'static mut self, f: F) -> &T
        where F: FnOnce() -> T
    {
        unsafe {
            let r = &mut self.0;
            self.1.call_once(|| {
                *r = Box::into_raw(Box::new(f()));
            });

            &*self.0
        }
    }
}

unsafe impl<T: Sync> Sync for Lazy<T> {}

#[macro_export]
macro_rules! __lazy_static_create {
    ($NAME:ident, $T:ty) => {
        use std::sync::ONCE_INIT;
        static mut $NAME: Lazy<$T> = Lazy(0 as *const $T, ONCE_INIT);
    }
}


macro_rules! lazy_static {
    ($(#[$attr:meta])* static ref $N:ident : $T:ty = $e:expr; $($t:tt)*) => {
        lazy_static!(@PRIV, $(#[$attr])* static ref $N : $T = $e; $($t)*);
    };
    ($(#[$attr:meta])* pub static ref $N:ident : $T:ty = $e:expr; $($t:tt)*) => {
        lazy_static!(@PUB, $(#[$attr])* static ref $N : $T = $e; $($t)*);
    };
    (@$VIS:ident, $(#[$attr:meta])* static ref $N:ident : $T:ty = $e:expr; $($t:tt)*) => {
        lazy_static!(@MAKE TY, $VIS, $(#[$attr])*, $N);
        impl ::std::ops::Deref for $N {
            type Target = $T;
            #[allow(unsafe_code)]
            fn deref<'a>(&'a self) -> &'a $T {
                unsafe {
                    #[inline(always)]
                    fn __static_ref_initialize() -> $T { $e }

                    #[inline(always)]
                    unsafe fn __stability() -> &'static $T {
                        __lazy_static_create!(LAZY, $T);
                        LAZY.get(__static_ref_initialize)
                    }
                    __stability()
                }
            }
        }
        lazy_static!($($t)*);
    };
    (@MAKE TY, PUB, $(#[$attr:meta])*, $N:ident) => {
        #[allow(missing_copy_implementations)]
        #[allow(non_camel_case_types)]
        #[allow(dead_code)]
        $(#[$attr])*
        pub struct $N {__private_field: ()}
        #[doc(hidden)]
        pub static $N: $N = $N {__private_field: ()};
    };
    (@MAKE TY, PRIV, $(#[$attr:meta])*, $N:ident) => {
        #[allow(missing_copy_implementations)]
        #[allow(non_camel_case_types)]
        #[allow(dead_code)]
        $(#[$attr])*
        struct $N {__private_field: ()}
        #[doc(hidden)]
        static $N: $N = $N {__private_field: ()};
    };
    () => ()
}


lazy_static! {
	/// EventUUID is used internally to index events, is randomly
	/// generated at first access.
	pub static ref EVENT_UUID: String = "asdf".to_string();
}

fn print_stuff(x: &'static String) { println!("{}",x)}

fn main() {
  print_stuff(&*EVENT_UUID)

}