1 // Copyright 2013 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 //! Implementation of running at_exit routines
13 //! Documentation can be found on the `rt::at_exit` function.
18 use sys_common::mutex::Mutex;
20 type Queue = Vec<Box<FnBox()>>;
22 // NB these are specifically not types from `std::sync` as they currently rely
23 // on poisoning and this module needs to operate at a lower level than requiring
24 // the thread infrastructure to be in place (useful on the borders of
25 // initialization/destruction).
26 static LOCK: Mutex = Mutex::new();
27 static mut QUEUE: *mut Queue = ptr::null_mut();
29 const DONE: *mut Queue = 1_usize as *mut _;
31 // The maximum number of times the cleanup routines will be run. While running
32 // the at_exit closures new ones may be registered, and this count is the number
33 // of times the new closures will be allowed to register successfully. After
34 // this number of iterations all new registrations will return `false`.
35 const ITERS: usize = 10;
37 unsafe fn init() -> bool {
39 let state: Box<Queue> = box Vec::new();
40 QUEUE = Box::into_raw(state);
41 } else if QUEUE == DONE {
42 // can't re-init after a cleanup
53 let _guard = LOCK.lock();
54 mem::replace(&mut QUEUE, if i == ITERS { DONE } else { ptr::null_mut() })
57 // make sure we're not recursively cleaning up
58 assert!(queue != DONE);
60 // If we never called init, not need to cleanup!
62 let queue: Box<Queue> = Box::from_raw(queue);
63 for to_run in *queue {
71 pub fn push(f: Box<FnBox()>) -> bool {
73 let _guard = LOCK.lock();