1 files changed, 63 insertions, 0 deletions
diff --git a/vendor/windows-core/src/out_param.rs b/vendor/windows-core/src/out_param.rs
new file mode 100644
index 00000000..828746c1
--- /dev/null
+++ b/vendor/windows-core/src/out_param.rs
@@ -0,0 +1,63 @@
+use super::*;
+use core::mem::{take, transmute_copy, zeroed};
+
+/// Provides automatic parameter conversion in cases where the Windows API expects implicit conversion support.
+///
+/// This is a mutable version of [Param] meant to support out parameters.
+/// There is no need to implement this trait. Blanket implementations are provided for all applicable Windows types.
+pub trait OutParam<T: TypeKind, C = <T as TypeKind>::TypeKind>: Sized
+where
+    T: Type<T>,
+{
+    #[doc(hidden)]
+    unsafe fn borrow_mut(&self) -> OutRef<'_, T>;
+}
+
+impl<T> OutParam<T, CloneType> for &mut T
+where
+    T: TypeKind<TypeKind = CloneType> + Clone + Default,
+{
+    unsafe fn borrow_mut(&self) -> OutRef<'_, T> {
+        unsafe {
+            let this: &mut T = transmute_copy(self);
+            take(this);
+            transmute_copy(self)
+        }
+    }
+}
+
+impl<T> OutParam<T, CopyType> for &mut T
+where
+    T: TypeKind<TypeKind = CopyType> + Clone + Default,
+{
+    unsafe fn borrow_mut(&self) -> OutRef<'_, T> {
+        unsafe { transmute_copy(self) }
+    }
+}
+
+impl<T> OutParam<T, InterfaceType> for &mut Option<T>
+where
+    T: TypeKind<TypeKind = InterfaceType> + Clone,
+{
+    unsafe fn borrow_mut(&self) -> OutRef<'_, T> {
+        unsafe {
+            let this: &mut Option<T> = transmute_copy(self);
+            take(this);
+            transmute_copy(self)
+        }
+    }
+}
+
+impl<T> OutParam<T> for Option<&mut T>
+where
+    T: Type<T>,
+{
+    unsafe fn borrow_mut(&self) -> OutRef<'_, T> {
+        unsafe {
+            match self {
+                Some(this) => transmute_copy(this),
+                None => zeroed(),
+            }
+        }
+    }
+}