uefi: return Result<Event> rather than Option<Event>

For all three functions, it is the normal / good case to be there. We can
also see this in the edk2 implementations of the corresponding functions.

Author: phip1611

uefi/src/proto/console/pointer/mod.rs

@@ -2,6 +2,7 @@
 
 //! Pointer device access.
 
+use crate::Error;
 use crate::proto::unsafe_protocol;
 use crate::{Event, Result, Status, StatusExt};
 use uefi_raw::protocol::console::SimplePointerProtocol;
@@ -53,9 +54,8 @@ impl Pointer {
     /// for input from the pointer device
     ///
     /// [`boot::wait_for_event`]: crate::boot::wait_for_event
-    #[must_use]
-    pub fn wait_for_input_event(&self) -> Option<Event> {
-        Event::from_ptr(self.0.wait_for_input)
+    pub fn wait_for_input_event(&self) -> Result<Event> {
+        Event::from_ptr(self.0.wait_for_input).ok_or(Error::from(Status::UNSUPPORTED))
     }
 
     /// Returns a reference to the pointer device information.

uefi/src/proto/console/text/input.rs

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: MIT OR Apache-2.0
 
 use crate::proto::unsafe_protocol;
-use crate::{Char16, Event, Result, Status, StatusExt};
+use crate::{Char16, Error, Event, Result, Status, StatusExt};
 use core::mem::MaybeUninit;
 use uefi_raw::protocol::console::{InputKey, SimpleTextInputProtocol};
 
@@ -84,9 +84,8 @@ impl Input {
     /// for a key to be available
     ///
     /// [`boot::wait_for_event`]: crate::boot::wait_for_event
-    #[must_use]
-    pub fn wait_for_key_event(&self) -> Option<Event> {
-        Event::from_ptr(self.0.wait_for_key)
+    pub fn wait_for_key_event(&self) -> Result<Event> {
+        Event::from_ptr(self.0.wait_for_key).ok_or(Error::from(Status::UNSUPPORTED))
     }
 }
 

uefi/src/proto/network/snp.rs

@@ -16,8 +16,9 @@ use core::ffi::c_void;
 use core::net::IpAddr;
 use core::ptr;
 use core::ptr::NonNull;
+use uefi::Error;
 use uefi_raw::protocol::network::snp::SimpleNetworkProtocol;
-use uefi_raw::{Boolean, IpAddress as EfiIpAddr, MacAddress as EfiMacAddr};
+use uefi_raw::{Boolean, IpAddress as EfiIpAddr, MacAddress as EfiMacAddr, Status};
 
 pub use uefi_raw::protocol::network::snp::{
     InterruptStatus, NetworkMode, NetworkState, NetworkStatistics, ReceiveFlags,
@@ -269,9 +270,8 @@ impl SimpleNetwork {
     ///
     /// On QEMU, this event seems to never fire; it is suggested to verify that your implementation
     /// of UEFI properly implements this event before using it.
-    #[must_use]
-    pub fn wait_for_packet_event(&self) -> Option<Event> {
-        Event::from_ptr(self.0.wait_for_packet)
+    pub fn wait_for_packet_event(&self) -> Result<Event> {
+        Event::from_ptr(self.0.wait_for_packet).ok_or(Error::from(Status::UNSUPPORTED))
     }
 
     /// Returns a reference to the Simple Network mode.