vendor/lazy_static-0.2.11/src/core_lazy.rs

   1 // Copyright 2016 lazy-static.rs Developers
   2 //
   3 // Licensed under the Apache License, Version 2.0, <LICENSE-APACHE or
   4 // http://apache.org/licenses/LICENSE-2.0> or the MIT license <LICENSE-MIT or
   5 // http://opensource.org/licenses/MIT>, at your option. This file may not be
   6 // copied, modified, or distributed except according to those terms.
   7
   8 extern crate spin;
   9
  10 use self::spin::Once;
  11
  12 pub struct Lazy<T: Sync>(Once<T>);
  13
  14 impl<T: Sync> Lazy<T> {
  15     #[inline(always)]
  16     pub const fn new() -> Self {
  17         Lazy(Once::new())
  18     }
  19
  20     #[inline(always)]
  21     pub fn get<F>(&'static self, builder: F) -> &T
  22         where F: FnOnce() -> T
  23     {
  24         self.0.call_once(builder)
  25     }
  26 }
  27
  28 #[macro_export]
  29 macro_rules! __lazy_static_create {
  30     ($NAME:ident, $T:ty) => {
  31         static $NAME: $crate::lazy::Lazy<$T> = $crate::lazy::Lazy::new();
  32     }
  33 }