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#![allow(non_camel_case_types, non_snake_case)]
use crate::co;
use crate::decl::*;
use crate::ole::{privs::*, vts::*};
com_interface! { IUnknown: "00000000-0000-0000-c000-000000000046";
/// [`IUnknown`](https://learn.microsoft.com/en-us/windows/win32/api/unknwn/nn-unknwn-iunknown)
/// COM interface. It's the base to all COM interfaces.
///
/// The `clone` method calls
/// [`AddRef`](https://learn.microsoft.com/en-us/windows/win32/api/unknwn/nf-unknwn-iunknown-addref)
/// internally.
///
/// Automatically calls
/// [`Release`](https://learn.microsoft.com/en-us/windows/win32/api/unknwn/nf-unknwn-iunknown-release)
/// when the object goes out of scope.
}
/// This trait is enabled with the `ole` feature, and provides methods for
/// [`IUnknown`](crate::IUnknown). It is the base trait for all COM traits.
///
/// Prefer importing this trait through the prelude:
///
/// ```no_run
/// use winsafe::prelude::*;
/// ```
///
/// Note that the `IUnknown` virtual table has two other methods: `AddRef` and
/// `Release`. While these methods are relevant in C++, here they are abstracted
/// away as it follows:
///
/// * `AddRef` – called along the `clone` method from the
/// [`Clone`](std::clone::Clone) trait;
///
/// * `Release` – called automatically by the [`Drop`](std::ops::Drop) trait, so
/// you don't need to worry about it.
pub trait ole_IUnknown: Clone {
/// The COM interface ID.
const IID: co::IID;
/// Creates an object from a COM virtual table pointer.
///
/// This method can be used as an escape hatch to interoperate with other
/// libraries.
///
/// # Panics
///
/// Panics if trying to create a custom COM implementation object.
///
/// # Safety
///
/// Be sure the pointer points to a properly allocated COM virtual table.
#[must_use]
unsafe fn from_ptr(p: *mut std::ffi::c_void) -> Self;
/// Returns the pointer to the underlying COM virtual table.
///
/// This method can be used as an escape hatch to interoperate with other
/// libraries.
#[must_use]
fn ptr(&self) -> *mut std::ffi::c_void;
/// Returns a mutable reference do the underlying COM virtual table pointer.
///
/// This method can be used as an escape hatch to interoperate with other
/// libraries.
///
/// # Panics
///
/// Panics if trying to modify a custom COM implementation object.
///
/// # Safety
///
/// Be sure the pointer being set points to a properly allocated COM virtual
/// table.
#[must_use]
unsafe fn as_mut(&mut self) -> &mut *mut std::ffi::c_void;
/// Creates an object from a null COM virtual table pointer.
///
/// # Safety
///
/// The pointer must be initialized before any call. Do not call methods on
/// a null COM pointer.
#[must_use]
unsafe fn null() -> Self {
Self::from_ptr(std::ptr::null_mut())
}
/// Returns the pointer to the underlying COM virtual table and sets the
/// internal pointer to null, so that
/// [`Release`](https://learn.microsoft.com/en-us/windows/win32/api/unknwn/nf-unknwn-iunknown-release)
/// won't be called.
///
/// Be sure to release the pointer, otherwise, as the name of this method
/// implies, you will cause a resource leak.
#[must_use]
fn leak(&mut self) -> *mut std::ffi::c_void {
let p = self.ptr();
unsafe { *self.as_mut() = std::ptr::null_mut(); }
p
}
/// [`IUnknown::QueryInterface`](https://learn.microsoft.com/en-us/windows/win32/api/unknwn/nf-unknwn-iunknown-queryinterface(refiid_void))
/// method.
#[must_use]
fn QueryInterface<T>(&self) -> HrResult<T>
where T: ole_IUnknown,
{
let mut queried = unsafe { T::null() };
ok_to_hrresult(
unsafe {
(vt::<IUnknownVT>(self).QueryInterface)(
self.ptr(),
&T::IID as *const _ as _,
queried.as_mut(),
)
},
).map(|_| queried)
}
}