use std::cell::UnsafeCell;
use std::fmt;
use std::ops::{Deref, DerefMut};
use std::panic::{RefUnwindSafe, UnwindSafe};
use std::sync::atomic::{fence, AtomicUsize, Ordering};
use std::sync::Arc;
use std::sync::{LockResult, TryLockError, TryLockResult};
use crate::std::queue::mpsc_list::Queue as WaitList;
use super::blocking::SyncBlocker;
use super::poison;
use crate::cancel::trigger_cancel_panic;
use crate::park::ParkError;
pub struct Mutex<T: ?Sized> {
to_wake: WaitList<Arc<SyncBlocker>>,
cnt: AtomicUsize,
poison: poison::Flag,
data: UnsafeCell<T>,
}
unsafe impl<T: ?Sized + Send> Send for Mutex<T> {}
unsafe impl<T: ?Sized + Send> Sync for Mutex<T> {}
impl<T: ?Sized> UnwindSafe for Mutex<T> {}
impl<T: ?Sized> RefUnwindSafe for Mutex<T> {}
pub struct MutexGuard<'a, T: ?Sized + 'a> {
__lock: &'a Mutex<T>,
__poison: poison::Guard,
}
impl<T> Mutex<T> {
pub fn new_arc(t: T) -> Arc<Mutex<T>> {
Arc::new(Self::new(t))
}
pub fn new(t: T) -> Mutex<T> {
Mutex {
to_wake: WaitList::new(),
cnt: AtomicUsize::new(0),
poison: poison::Flag::new(),
data: UnsafeCell::new(t),
}
}
}
impl<T: ?Sized> Mutex<T> {
pub fn lock(&self) -> LockResult<MutexGuard<T>> {
match self.try_lock() {
Ok(g) => return Ok(g),
Err(TryLockError::WouldBlock) => {}
Err(TryLockError::Poisoned(e)) => return Err(e),
}
let cur = SyncBlocker::current();
self.to_wake.push(cur.clone());
if self.cnt.fetch_add(1, Ordering::SeqCst) == 0 {
self.to_wake
.pop()
.map(|w| self.unpark_one(&w))
.expect("got null blocker!");
}
loop {
match cur.park(None) {
Ok(_) => {
break;
}
Err(ParkError::Timeout) => unreachable!("mutex timeout"),
Err(ParkError::Canceled) => {
let b_ignore = if crate::coroutine_impl::is_coroutine() {
let cancel = crate::coroutine_impl::current_cancel_data();
cancel.is_disabled()
} else {
false
};
if cur.is_unparked() {
if b_ignore {
break;
}
self.unlock();
} else {
cur.set_release();
if cur.is_unparked() && cur.take_release() {
if b_ignore {
break;
}
self.unlock();
}
}
if b_ignore {
continue;
}
trigger_cancel_panic();
}
}
}
MutexGuard::new(self)
}
pub fn try_lock(&self) -> TryLockResult<MutexGuard<T>> {
if self.cnt.load(Ordering::SeqCst) == 0 {
match self
.cnt
.compare_exchange(0, 1, Ordering::SeqCst, Ordering::SeqCst)
{
Ok(_) => Ok(MutexGuard::new(self)?),
Err(_) => Err(TryLockError::WouldBlock),
}
} else {
Err(TryLockError::WouldBlock)
}
}
fn unpark_one(&self, w: &SyncBlocker) -> Result<(), ParkError> {
w.unpark()?;
if w.take_release() {
self.unlock();
}
Ok(())
}
fn unlock(&self) {
if self.cnt.fetch_sub(1, Ordering::SeqCst) > 1 {
self.to_wake
.pop()
.map(|w| self.unpark_one(&w));
}
}
#[inline]
pub fn is_poisoned(&self) -> bool {
self.poison.get()
}
pub fn into_inner(self) -> LockResult<T>
where
T: Sized,
{
let data = self.data.into_inner();
poison::map_result(self.poison.borrow(), |_| data)
}
pub fn get_mut(&mut self) -> LockResult<&mut T> {
let data = unsafe { &mut *self.data.get() };
poison::map_result(self.poison.borrow(), |_| data)
}
}
impl<T: ?Sized + Default> Default for Mutex<T> {
fn default() -> Mutex<T> {
Mutex::new(Default::default())
}
}
impl<T: ?Sized + fmt::Debug> fmt::Debug for Mutex<T> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match self.try_lock() {
Ok(guard) => write!(f, "Mutex {{ data: {:?} }}", &*guard),
Err(TryLockError::Poisoned(err)) => {
write!(f, "Mutex {{ data: Poisoned({:?}) }}", &**err.get_ref())
}
Err(TryLockError::WouldBlock) => write!(f, "Mutex {{ <locked> }}"),
}
}
}
impl<'mutex, T: ?Sized> MutexGuard<'mutex, T> {
fn new(lock: &'mutex Mutex<T>) -> LockResult<MutexGuard<'mutex, T>> {
fence(Ordering::SeqCst);
poison::map_result(lock.poison.borrow(), |guard| MutexGuard {
__lock: lock,
__poison: guard,
})
}
}
impl<'mutex, T: ?Sized> Deref for MutexGuard<'mutex, T> {
type Target = T;
fn deref(&self) -> &T {
unsafe { &*self.__lock.data.get() }
}
}
impl<'mutex, T: ?Sized> DerefMut for MutexGuard<'mutex, T> {
fn deref_mut(&mut self) -> &mut T {
unsafe { &mut *self.__lock.data.get() }
}
}
impl<'a, T: ?Sized> Drop for MutexGuard<'a, T> {
#[inline]
fn drop(&mut self) {
self.__lock.poison.done(&self.__poison);
self.__lock.unlock();
fence(Ordering::SeqCst);
}
}
impl<'a, T: ?Sized + fmt::Debug> fmt::Debug for MutexGuard<'a, T> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
f.debug_struct("MutexGuard")
.field("lock", &self.__lock)
.finish()
}
}
pub fn unlock_mutex<T: ?Sized>(lock: &Mutex<T>) {
lock.unlock();
}
pub fn guard_lock<'a, T: ?Sized>(guard: &MutexGuard<'a, T>) -> &'a Mutex<T> {
guard.__lock
}
pub fn guard_poison<'a, T: ?Sized>(guard: &MutexGuard<'a, T>) -> &'a poison::Flag {
&guard.__lock.poison
}
#[cfg(test)]
mod tests {
#![feature(test)]
use super::*;
use crate::std::sync::channel::channel;
use crate::std::sync::Condvar;
use std::sync::atomic::{AtomicUsize, Ordering};
use std::sync::Arc;
use std::thread;
struct Packet<T>(Arc<(Mutex<T>, Condvar)>);
unsafe impl<T: Send> Send for Packet<T> {}
unsafe impl<T> Sync for Packet<T> {}
#[derive(Eq, PartialEq, Debug)]
struct NonCopy(i32);
#[test]
fn smoke() {
let m = Mutex::new(());
drop(m.lock().unwrap());
drop(m.lock().unwrap());
}
#[test]
fn lots_and_lots() {
const J: u32 = 1000;
const K: u32 = 3;
let m = Arc::new(Mutex::new(0));
fn inc(m: &Mutex<u32>) {
for _ in 0..J {
*m.lock().unwrap() += 1;
}
}
let (tx, rx) = channel();
for _ in 0..K {
let tx2 = tx.clone();
let m2 = m.clone();
thread::spawn(move || {
inc(&m2);
tx2.send(()).unwrap();
});
let tx2 = tx.clone();
let m2 = m.clone();
go!(move || {
inc(&m2);
tx2.send(()).unwrap();
});
}
drop(tx);
for _ in 0..2 * K {
rx.recv().unwrap();
}
assert_eq!(*m.lock().unwrap(), J * K * 2);
}
#[test]
fn try_lock() {
let m = Mutex::new(());
*m.try_lock().unwrap() = ();
}
#[test]
fn test_into_inner() {
let m = Mutex::new(NonCopy(10));
assert_eq!(m.into_inner().unwrap(), NonCopy(10));
}
#[test]
fn test_into_inner_drop() {
struct Foo(Arc<AtomicUsize>);
impl Drop for Foo {
fn drop(&mut self) {
self.0.fetch_add(1, Ordering::SeqCst);
}
}
let num_drops = Arc::new(AtomicUsize::new(0));
let m = Mutex::new(Foo(num_drops.clone()));
assert_eq!(num_drops.load(Ordering::SeqCst), 0);
{
let _inner = m.into_inner().unwrap();
assert_eq!(num_drops.load(Ordering::SeqCst), 0);
}
assert_eq!(num_drops.load(Ordering::SeqCst), 1);
}
#[test]
fn test_into_inner_poison() {
let m = Arc::new(Mutex::new(NonCopy(10)));
let m2 = m.clone();
let _ = thread::spawn(move || {
let _lock = m2.lock().unwrap();
panic!("test panic in inner thread to poison mutex");
})
.join();
assert!(m.is_poisoned());
match Arc::try_unwrap(m).unwrap().into_inner() {
Err(e) => assert_eq!(e.into_inner(), NonCopy(10)),
Ok(x) => panic!("into_inner of poisoned Mutex is Ok: {:?}", x),
}
}
#[test]
fn test_get_mut() {
let mut m = Mutex::new(NonCopy(10));
*m.get_mut().unwrap() = NonCopy(20);
assert_eq!(m.into_inner().unwrap(), NonCopy(20));
}
#[test]
fn test_get_mut_poison() {
let m = Arc::new(Mutex::new(NonCopy(10)));
let m2 = m.clone();
let _ = thread::spawn(move || {
let _lock = m2.lock().unwrap();
panic!("test panic in inner thread to poison mutex");
})
.join();
assert!(m.is_poisoned());
match Arc::try_unwrap(m).unwrap().get_mut() {
Err(e) => assert_eq!(*e.into_inner(), NonCopy(10)),
Ok(x) => panic!("get_mut of poisoned Mutex is Ok: {:?}", x),
}
}
#[test]
fn test_mutex_arc_condvar() {
let packet = Packet(Arc::new((Mutex::new(false), Condvar::new())));
let packet2 = Packet(packet.0.clone());
let (tx, rx) = channel();
let _t = thread::spawn(move || {
rx.recv().unwrap();
let &(ref lock, ref cvar) = &*packet2.0;
let mut lock = lock.lock().unwrap();
*lock = true;
cvar.notify_one();
});
let &(ref lock, ref cvar) = &*packet.0;
let mut lock = lock.lock().unwrap();
tx.send(()).unwrap();
assert!(!*lock);
while !*lock {
lock = cvar.wait(lock).unwrap();
}
}
#[test]
fn test_arc_condvar_poison() {
let packet = Packet(Arc::new((Mutex::new(1), Condvar::new())));
let packet2 = Packet(packet.0.clone());
let (tx, rx) = channel();
let _t = thread::spawn(move || -> () {
rx.recv().unwrap();
let &(ref lock, ref cvar) = &*packet2.0;
let _g = lock.lock().unwrap();
cvar.notify_one();
panic!();
});
let &(ref lock, ref cvar) = &*packet.0;
let mut lock = lock.lock().unwrap();
tx.send(()).unwrap();
while *lock == 1 {
match cvar.wait(lock) {
Ok(l) => {
lock = l;
assert_eq!(*lock, 1);
}
Err(..) => break,
}
}
}
#[test]
fn test_mutex_arc_poison() {
let arc = Arc::new(Mutex::new(1));
assert!(!arc.is_poisoned());
let arc2 = arc.clone();
let _ = thread::spawn(move || {
let lock = arc2.lock().unwrap();
assert_eq!(*lock, 2);
})
.join();
assert!(arc.lock().is_err());
assert!(arc.is_poisoned());
}
#[test]
fn test_mutex_arc_nested() {
let arc = Arc::new(Mutex::new(1));
let arc2 = Arc::new(Mutex::new(arc));
let (tx, rx) = channel();
let _t = thread::spawn(move || {
let lock = arc2.lock().unwrap();
let lock2 = lock.lock().unwrap();
assert_eq!(*lock2, 1);
tx.send(()).unwrap();
});
rx.recv().unwrap();
}
#[test]
fn test_mutex_arc_access_in_unwind() {
let arc = Arc::new(Mutex::new(1));
let arc2 = arc.clone();
let _ = thread::spawn(move || -> () {
struct Unwinder {
i: Arc<Mutex<i32>>,
}
impl Drop for Unwinder {
fn drop(&mut self) {
*self.i.lock().unwrap() += 1;
}
}
let _u = Unwinder { i: arc2 };
panic!();
})
.join();
let lock = arc.lock().unwrap();
assert_eq!(*lock, 2);
}
#[test]
fn test_mutex_unsized() {
let mutex: &Mutex<[i32]> = &Mutex::new([1, 2, 3]);
{
let b = &mut *mutex.lock().unwrap();
b[0] = 4;
b[2] = 5;
}
let comp: &[i32] = &[4, 2, 5];
assert_eq!(&*mutex.lock().unwrap(), comp);
}
#[test]
fn test_mutex_canceled() {
use crate::sleep::sleep;
use std::mem::drop;
use std::time::Duration;
let mutex1 = Arc::new(Mutex::new(0));
let mutex2 = mutex1.clone();
let mutex3 = mutex1.clone();
let g = mutex1.lock().unwrap();
let h1 = go!(move || {
let mut g = mutex2.lock().unwrap();
*g += 1;
});
let h2 = go!(move || {
sleep(Duration::from_millis(50));
let mut g = mutex3.lock().unwrap();
*g += 1;
});
sleep(Duration::from_millis(100));
unsafe { h1.coroutine().cancel() };
h1.join().unwrap_err();
drop(g);
h2.join().unwrap();
let g = mutex1.lock().unwrap();
assert_eq!(*g, 1);
}
#[test]
fn test_mutex_canceled_by_other_wait() {
use crate::sleep::sleep;
use std::mem::drop;
use std::time::Duration;
let mutex1 = Arc::new(Mutex::new(0));
let mutex2 = mutex1.clone();
let mutex3 = mutex1.clone();
let g = mutex1.lock().unwrap();
let h1 = go!(move || {
let mut g = mutex2.lock().unwrap();
sleep(Duration::from_secs(10000));
*g += 1;
});
let h2 = go!(move || {
sleep(Duration::from_millis(50));
let mut g = mutex3.lock().unwrap();
*g += 1;
});
sleep(Duration::from_millis(100));
drop(g);
sleep(Duration::from_millis(50));
unsafe { h1.coroutine().cancel() };
h1.join().unwrap_err();
h2.join().unwrap();
let g = mutex1.lock().unwrap();
assert_eq!(*g, 1);
}
}