1 files changed, 56 insertions, 0 deletions
diff --git a/library/std/src/sys/windows/condvar.rs b/library/std/src/sys/windows/condvar.rs
new file mode 100644
index 00000000000..8f7f6854cc2
--- /dev/null
+++ b/library/std/src/sys/windows/condvar.rs
@@ -0,0 +1,56 @@
+use crate::cell::UnsafeCell;
+use crate::sys::c;
+use crate::sys::mutex::{self, Mutex};
+use crate::sys::os;
+use crate::time::Duration;
+
+pub struct Condvar {
+    inner: UnsafeCell<c::CONDITION_VARIABLE>,
+}
+
+unsafe impl Send for Condvar {}
+unsafe impl Sync for Condvar {}
+
+impl Condvar {
+    pub const fn new() -> Condvar {
+        Condvar { inner: UnsafeCell::new(c::CONDITION_VARIABLE_INIT) }
+    }
+
+    #[inline]
+    pub unsafe fn init(&mut self) {}
+
+    #[inline]
+    pub unsafe fn wait(&self, mutex: &Mutex) {
+        let r = c::SleepConditionVariableSRW(self.inner.get(), mutex::raw(mutex), c::INFINITE, 0);
+        debug_assert!(r != 0);
+    }
+
+    pub unsafe fn wait_timeout(&self, mutex: &Mutex, dur: Duration) -> bool {
+        let r = c::SleepConditionVariableSRW(
+            self.inner.get(),
+            mutex::raw(mutex),
+            super::dur2timeout(dur),
+            0,
+        );
+        if r == 0 {
+            debug_assert_eq!(os::errno() as usize, c::ERROR_TIMEOUT as usize);
+            false
+        } else {
+            true
+        }
+    }
+
+    #[inline]
+    pub unsafe fn notify_one(&self) {
+        c::WakeConditionVariable(self.inner.get())
+    }
+
+    #[inline]
+    pub unsafe fn notify_all(&self) {
+        c::WakeAllConditionVariable(self.inner.get())
+    }
+
+    pub unsafe fn destroy(&self) {
+        // ...
+    }
+}