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use crate::*;
use bindings::Windows::Win32::System::WinRT::IWeakReferenceSource;
pub unsafe trait Interface: Sized + Abi {
type Vtable;
const IID: Guid;
unsafe fn vtable(&self) -> &Self::Vtable {
self.assume_vtable::<Self>()
}
unsafe fn assume_vtable<T: Interface>(&self) -> &T::Vtable {
let this: RawPtr = std::mem::transmute_copy(self);
&(*(*(this as *mut *mut _) as *mut _))
}
unsafe fn query(&self, iid: *const Guid, interface: *mut RawPtr) -> HRESULT {
(self.assume_vtable::<IUnknown>().0)(std::mem::transmute_copy(self), iid, interface)
}
fn cast<T: Interface>(&self) -> Result<T> {
unsafe {
let mut result = None;
(self.assume_vtable::<IUnknown>().0)(
std::mem::transmute_copy(self),
&T::IID,
&mut result as *mut _ as _,
)
.and_some(result)
}
}
fn downgrade(&self) -> Result<Weak<Self>> {
self.cast::<IWeakReferenceSource>()
.and_then(|source| Weak::downgrade(&source))
}
}