// SPDX-License-Identifier: GPL-2.0 OR MIT //! DRM File objects.//!//! C header: [`include/drm/drm_file.h`](srctree/include/drm/drm_file.h) use crate::{bindings, drm, error::Result, prelude::*, types::Opaque};use core::marker::PhantomData;use core::pin::Pin; /// Trait that must be implemented by DRM drivers to represent a DRM File (a client instance).pub trait DriverFile {    /// The parent `Driver` implementation for this `DriverFile`.    type Driver: drm::Driver;     /// Open a new file (called when a client opens the DRM device).    fn open(device: &drm::Device<Self::Driver>) -> Result<Pin<KBox<Self>>>;} /// An open DRM File.////// # Invariants////// `self.0` is a valid instance of a `struct drm_file`.#[repr(transparent)]pub struct File<T: DriverFile>(Opaque<bindings::drm_file>, PhantomData<T>); impl<T: DriverFile> File<T> {    #[doc(hidden)]    /// Not intended to be called externally, except via declare_drm_ioctls!()    ///    /// # Safety    ///    /// `raw_file` must be a valid pointer to an open `struct drm_file`, opened through `T::open`.    pub unsafe fn from_raw<'a>(ptr: *mut bindings::drm_file) -> &'a File<T> {        // SAFETY: `raw_file` is valid by the safety requirements of this function.        unsafe { &*ptr.cast() }    }     pub(super) fn as_raw(&self) -> *mut bindings::drm_file {        self.0.get()    }     fn driver_priv(&self) -> *mut T {        // SAFETY: By the type invariants of `Self`, `self.as_raw()` is always valid.        unsafe { (*self.as_raw()).driver_priv }.cast()    }     /// Return a pinned reference to the driver file structure.    pub fn inner(&self) -> Pin<&T> {        // SAFETY: By the type invariant the pointer `self.as_raw()` points to a valid and opened        // `struct drm_file`, hence `driver_priv` has been properly initialized by `open_callback`.        unsafe { Pin::new_unchecked(&*(self.driver_priv())) }    }     /// The open callback of a `struct drm_file`.    pub(crate) extern "C" fn open_callback(        raw_dev: *mut bindings::drm_device,        raw_file: *mut bindings::drm_file,    ) -> core::ffi::c_int {        // SAFETY: A callback from `struct drm_driver::open` guarantees that        // - `raw_dev` is valid pointer to a `struct drm_device`,        // - the corresponding `struct drm_device` has been registered.        let drm = unsafe { drm::Device::from_raw(raw_dev) };         // SAFETY: `raw_file` is a valid pointer to a `struct drm_file`.        let file = unsafe { File::<T>::from_raw(raw_file) };         let inner = match T::open(drm) {            Err(e) => {                return e.to_errno();            }            Ok(i) => i,        };         // SAFETY: This pointer is treated as pinned, and the Drop guarantee is upheld in        // `postclose_callback()`.        let driver_priv = KBox::into_raw(unsafe { Pin::into_inner_unchecked(inner) });         // SAFETY: By the type invariants of `Self`, `self.as_raw()` is always valid.        unsafe { (*file.as_raw()).driver_priv = driver_priv.cast() };         0    }     /// The postclose callback of a `struct drm_file`.    pub(crate) extern "C" fn postclose_callback(        _raw_dev: *mut bindings::drm_device,        raw_file: *mut bindings::drm_file,    ) {        // SAFETY: This reference won't escape this function        let file = unsafe { File::<T>::from_raw(raw_file) };         // SAFETY: `file.driver_priv` has been created in `open_callback` through `KBox::into_raw`.        let _ = unsafe { KBox::from_raw(file.driver_priv()) };    }} impl<T: DriverFile> super::private::Sealed for File<T> {}