diff --git a/library/std/src/io/stdio.rs b/library/std/src/io/stdio.rs index 9b6bd70523da..b68e538c19fb 100644 --- a/library/std/src/io/stdio.rs +++ b/library/std/src/io/stdio.rs @@ -9,6 +9,7 @@ use crate::cell::RefCell; use crate::fmt; use crate::io::{self, BufReader, Initializer, IoSlice, IoSliceMut, LineWriter}; use crate::lazy::SyncOnceCell; +use crate::pin::Pin; use crate::sync::atomic::{AtomicBool, Ordering}; use crate::sync::{Mutex, MutexGuard}; use crate::sys::stdio; @@ -488,7 +489,7 @@ pub struct Stdout { // FIXME: this should be LineWriter or BufWriter depending on the state of // stdout (tty or not). Note that if this is not line buffered it // should also flush-on-panic or some form of flush-on-abort. - inner: &'static ReentrantMutex>>, + inner: Pin<&'static ReentrantMutex>>>, } /// A locked reference to the `Stdout` handle. @@ -548,25 +549,29 @@ pub struct StdoutLock<'a> { pub fn stdout() -> Stdout { static INSTANCE: SyncOnceCell>>> = SyncOnceCell::new(); + + fn cleanup() { + if let Some(instance) = INSTANCE.get() { + // Flush the data and disable buffering during shutdown + // by replacing the line writer by one with zero + // buffering capacity. + // We use try_lock() instead of lock(), because someone + // might have leaked a StdoutLock, which would + // otherwise cause a deadlock here. + if let Some(lock) = Pin::static_ref(instance).try_lock() { + *lock.borrow_mut() = LineWriter::with_capacity(0, stdout_raw()); + } + } + } + Stdout { - inner: INSTANCE.get_or_init(|| unsafe { - let _ = sys_common::at_exit(|| { - if let Some(instance) = INSTANCE.get() { - // Flush the data and disable buffering during shutdown - // by replacing the line writer by one with zero - // buffering capacity. - // We use try_lock() instead of lock(), because someone - // might have leaked a StdoutLock, which would - // otherwise cause a deadlock here. - if let Some(lock) = instance.try_lock() { - *lock.borrow_mut() = LineWriter::with_capacity(0, stdout_raw()); - } - } - }); - let r = ReentrantMutex::new(RefCell::new(LineWriter::new(stdout_raw()))); - r.init(); - r - }), + inner: Pin::static_ref(&INSTANCE).get_or_init_pin( + || unsafe { + let _ = sys_common::at_exit(cleanup); + ReentrantMutex::new(RefCell::new(LineWriter::new(stdout_raw()))) + }, + |mutex| unsafe { mutex.init() }, + ), } } @@ -698,7 +703,7 @@ impl fmt::Debug for StdoutLock<'_> { /// an error. #[stable(feature = "rust1", since = "1.0.0")] pub struct Stderr { - inner: &'static ReentrantMutex>, + inner: Pin<&'static ReentrantMutex>>, } /// A locked reference to the `Stderr` handle. @@ -760,11 +765,10 @@ pub fn stderr() -> Stderr { static INSTANCE: SyncOnceCell>> = SyncOnceCell::new(); Stderr { - inner: INSTANCE.get_or_init(|| unsafe { - let r = ReentrantMutex::new(RefCell::new(stderr_raw())); - r.init(); - r - }), + inner: Pin::static_ref(&INSTANCE).get_or_init_pin( + || unsafe { ReentrantMutex::new(RefCell::new(stderr_raw())) }, + |mutex| unsafe { mutex.init() }, + ), } } diff --git a/library/std/src/lib.rs b/library/std/src/lib.rs index e9ac7875cc26..5aa9d6a3562f 100644 --- a/library/std/src/lib.rs +++ b/library/std/src/lib.rs @@ -291,6 +291,7 @@ #![feature(panic_info_message)] #![feature(panic_internals)] #![feature(panic_unwind)] +#![feature(pin_static_ref)] #![feature(prelude_import)] #![feature(ptr_internals)] #![feature(raw)]