Move boxing and mutex checking logic of condvar into sys_common.

library/std/src/sync/condvar.rs

@@ -2,10 +2,8 @@
 mod tests;
 
 use crate::fmt;
-use crate::sync::atomic::{AtomicUsize, Ordering};
 use crate::sync::{mutex, MutexGuard, PoisonError};
 use crate::sys_common::condvar as sys;
-use crate::sys_common::mutex as sys_mutex;
 use crate::sys_common::poison::{self, LockResult};
 use crate::time::{Duration, Instant};
 
@@ -109,8 +107,7 @@ impl WaitTimeoutResult {
 /// ```
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct Condvar {
-    inner: Box<sys::Condvar>,
-    mutex: AtomicUsize,
+    inner: sys::Condvar,
 }
 
 impl Condvar {
@@ -126,11 +123,7 @@ impl Condvar {
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn new() -> Condvar {
-        let mut c = Condvar { inner: box sys::Condvar::new(), mutex: AtomicUsize::new(0) };
-        unsafe {
-            c.inner.init();
-        }
-        c
+        Condvar { inner: sys::Condvar::new() }
     }
 
     /// Blocks the current thread until this condition variable receives a
@@ -192,7 +185,6 @@ impl Condvar {
     pub fn wait<'a, T>(&self, guard: MutexGuard<'a, T>) -> LockResult<MutexGuard<'a, T>> {
         let poisoned = unsafe {
             let lock = mutex::guard_lock(&guard);
-            self.verify(lock);
             self.inner.wait(lock);
             mutex::guard_poison(&guard).get()
         };
@@ -389,7 +381,6 @@ impl Condvar {
     ) -> LockResult<(MutexGuard<'a, T>, WaitTimeoutResult)> {
         let (poisoned, result) = unsafe {
             let lock = mutex::guard_lock(&guard);
-            self.verify(lock);
             let success = self.inner.wait_timeout(lock, dur);
             (mutex::guard_poison(&guard).get(), WaitTimeoutResult(!success))
         };
@@ -510,7 +501,7 @@ impl Condvar {
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn notify_one(&self) {
-        unsafe { self.inner.notify_one() }
+        self.inner.notify_one()
     }
 
     /// Wakes up all blocked threads on this condvar.
@@ -550,27 +541,7 @@ impl Condvar {
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn notify_all(&self) {
-        unsafe { self.inner.notify_all() }
-    }
-
-    fn verify(&self, mutex: &sys_mutex::MovableMutex) {
-        let addr = mutex.raw() as *const _ as usize;
-        match self.mutex.compare_and_swap(0, addr, Ordering::SeqCst) {
-            // If we got out 0, then we have successfully bound the mutex to
-            // this cvar.
-            0 => {}
-
-            // If we get out a value that's the same as `addr`, then someone
-            // already beat us to the punch.
-            n if n == addr => {}
-
-            // Anything else and we're using more than one mutex on this cvar,
-            // which is currently disallowed.
-            _ => panic!(
-                "attempted to use a condition variable with two \
-                         mutexes"
-            ),
-        }
+        self.inner.notify_all()
     }
 }
 
@@ -588,10 +559,3 @@ impl Default for Condvar {
         Condvar::new()
     }
 }
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl Drop for Condvar {
-    fn drop(&mut self) {
-        unsafe { self.inner.destroy() }
-    }
-}