diff options
Diffstat (limited to 'src/libstd/sys_common/at_exit_imp.rs')
| -rw-r--r-- | src/libstd/sys_common/at_exit_imp.rs | 75 | 
1 files changed, 0 insertions, 75 deletions
| diff --git a/src/libstd/sys_common/at_exit_imp.rs b/src/libstd/sys_common/at_exit_imp.rs deleted file mode 100644 index 6b799db856e..00000000000 --- a/src/libstd/sys_common/at_exit_imp.rs +++ /dev/null @@ -1,75 +0,0 @@ -//! Implementation of running at_exit routines -//! -//! Documentation can be found on the `rt::at_exit` function. - -use crate::mem; -use crate::ptr; -use crate::sys_common::mutex::Mutex; - -type Queue = Vec<Box<dyn FnOnce()>>; - -// NB these are specifically not types from `std::sync` as they currently rely -// on poisoning and this module needs to operate at a lower level than requiring -// the thread infrastructure to be in place (useful on the borders of -// initialization/destruction). -// We never call `LOCK.init()`, so it is UB to attempt to -// acquire this mutex reentrantly! -static LOCK: Mutex = Mutex::new(); -static mut QUEUE: *mut Queue = ptr::null_mut(); - -const DONE: *mut Queue = 1_usize as *mut _; - -// The maximum number of times the cleanup routines will be run. While running -// the at_exit closures new ones may be registered, and this count is the number -// of times the new closures will be allowed to register successfully. After -// this number of iterations all new registrations will return `false`. -const ITERS: usize = 10; - -unsafe fn init() -> bool { - if QUEUE.is_null() { - let state: Box<Queue> = box Vec::new(); - QUEUE = Box::into_raw(state); - } else if QUEUE == DONE { - // can't re-init after a cleanup - return false; - } - - true -} - -pub fn cleanup() { - for i in 1..=ITERS { - unsafe { - let queue = { - let _guard = LOCK.lock(); - mem::replace(&mut QUEUE, if i == ITERS { DONE } else { ptr::null_mut() }) - }; - - // make sure we're not recursively cleaning up - assert!(queue != DONE); - - // If we never called init, not need to cleanup! - if !queue.is_null() { - let queue: Box<Queue> = Box::from_raw(queue); - for to_run in *queue { - // We are not holding any lock, so reentrancy is fine. - to_run(); - } - } - } - } -} - -pub fn push(f: Box<dyn FnOnce()>) -> bool { - unsafe { - let _guard = LOCK.lock(); - if init() { - // We are just moving `f` around, not calling it. - // There is no possibility of reentrancy here. - (*QUEUE).push(f); - true - } else { - false - } - } -} | 
