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#![no_std] extern crate alloc; #[macro_use] extern crate lazy_static; use alloc::boxed::Box; use alloc::collections::linked_list::LinkedList; use core::any::Any; use core::any::TypeId; use spin::Mutex; lazy_static! { static ref GLOBALS_LIST: Mutex<LinkedList<(TypeId, &'static Mutex<dyn Any + Send + Sync>)>> = { Mutex::new(LinkedList::new()) }; } pub fn get<T>() -> &'static Mutex<T> where T: 'static + Default + Send + core::marker::Sync, { { let mut globals = GLOBALS_LIST.lock(); let id = TypeId::of::<T>(); let p = globals.iter().find(|&r| r.0 == id); if let Some(v) = p { return unsafe { &*(v.1 as *const Mutex<dyn Any + Send + Sync> as *const Mutex<T>) }; } let v = Box::new(Mutex::new(T::default())); let handle = Box::leak(v); globals.push_front((id, handle)); } get() } #[cfg(test)] mod test { use crate::*; use alloc::vec::Vec; #[derive(Default)] struct Foo { x: u32, } #[derive(Default)] struct Bar { x: u32, } #[test] fn basic() { let f = get::<Foo>().lock(); let b = get::<Bar>().lock(); assert_eq!(0, f.x); assert_eq!(0, b.x); } #[test] fn basic_2() { { let mut f = get::<Vec<u32>>().lock(); let _b = get::<Vec<u8>>().lock(); f.resize(2_000_000, 0); } { let mut f = get::<Vec<u32>>().lock(); assert_eq!(2_000_000, f.len()); f.resize(100, 0); } { let f = get::<Vec<u32>>().lock(); assert_eq!(100, f.len()); } } }