1 files changed, 31 insertions, 0 deletions
diff --git a/src/libstd/sys/windows/mutex.rs b/src/libstd/sys/windows/mutex.rs
index 0847f3b52bf..ca20858bb5b 100644
--- a/src/libstd/sys/windows/mutex.rs
+++ b/src/libstd/sys/windows/mutex.rs
@@ -12,6 +12,7 @@ use prelude::v1::*;
 
 use cell::UnsafeCell;
 use sys::sync as ffi;
+use mem;
 
 pub struct Mutex { inner: UnsafeCell<ffi::SRWLOCK> }
 
@@ -57,3 +58,33 @@ impl Mutex {
         // ...
     }
 }
+
+pub struct ReentrantMutex { inner: Box<UnsafeCell<ffi::CRITICAL_SECTION>> }
+
+unsafe impl Send for ReentrantMutex {}
+unsafe impl Sync for ReentrantMutex {}
+
+impl ReentrantMutex {
+    pub unsafe fn new() -> ReentrantMutex {
+        let mutex = ReentrantMutex { inner: box mem::uninitialized() };
+        ffi::InitializeCriticalSection(mutex.inner.get());
+        mutex
+    }
+
+    pub unsafe fn lock(&self) {
+        ffi::EnterCriticalSection(self.inner.get());
+    }
+
+    #[inline]
+    pub unsafe fn try_lock(&self) -> bool {
+        ffi::TryEnterCriticalSection(self.inner.get()) != 0
+    }
+
+    pub unsafe fn unlock(&self) {
+        ffi::LeaveCriticalSection(self.inner.get());
+    }
+
+    pub unsafe fn destroy(&self) {
+        ffi::DeleteCriticalSection(self.inner.get());
+    }
+}