sgx_tstd/src/sys_common/thread_info.rs

// Copyright (C) 2017-2018 Baidu, Inc. All Rights Reserved.
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use thread::SgxThread;
use core::cell::RefCell;

struct SgxThreadInfo {
    thread: SgxThread,
}

thread_local! { static THREAD_INFO: RefCell<Option<SgxThreadInfo>> = RefCell::new(None) }

impl SgxThreadInfo {

    fn with<R, F>(f: F) -> Option<R> where F: FnOnce(&mut SgxThreadInfo) -> R {
        THREAD_INFO.try_with(move |c| {
            if c.borrow().is_none() {
                *c.borrow_mut() = Some(SgxThreadInfo {
                    thread: SgxThread::new(),
                })
            }
            f(c.borrow_mut().as_mut().unwrap())
        }).ok()
    }
}

pub fn current_thread() -> Option<SgxThread> {
    SgxThreadInfo::with(|info| info.thread.clone())
}

pub fn set(thread: SgxThread) {
    THREAD_INFO.with(|c| assert!(c.borrow().is_none()));
    THREAD_INFO.with(move |c| *c.borrow_mut() = Some(SgxThreadInfo{
        thread,
    }));
}