From 9833ee17e09abdc132899a5d4c161979f5f0f54e Mon Sep 17 00:00:00 2001
From: Timothy Roberts <39689890+timrobertsdev@users.noreply.github.com>
Date: Wed, 7 Sep 2022 01:44:17 -0400
Subject: [PATCH 1/3] Change `Event` to be FFI-safe using `NonNull`

---
 src/data_types/mod.rs                          | 2 +-
 src/proto/media/disk.rs                        | 2 +-
 uefi-test-runner/src/proto/media/known_disk.rs | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/data_types/mod.rs b/src/data_types/mod.rs
index f369f25fd..e4058725c 100644
--- a/src/data_types/mod.rs
+++ b/src/data_types/mod.rs
@@ -39,7 +39,7 @@ impl Handle {
 
 /// Handle to an event structure
 #[repr(transparent)]
-pub struct Event(*mut c_void);
+pub struct Event(NonNull<c_void>);
 
 impl Event {
     /// Clone this `Event`
diff --git a/src/proto/media/disk.rs b/src/proto/media/disk.rs
index 9cf7926a7..56e54b6ef 100644
--- a/src/proto/media/disk.rs
+++ b/src/proto/media/disk.rs
@@ -74,7 +74,7 @@ impl DiskIo {
 #[repr(C)]
 pub struct DiskIo2Token {
     /// Event to be signalled when an asynchronous disk I/O operation completes.
-    pub event: Event,
+    pub event: Option<Event>,
     /// Transaction status code.
     pub transaction_status: Status,
 }
diff --git a/uefi-test-runner/src/proto/media/known_disk.rs b/uefi-test-runner/src/proto/media/known_disk.rs
index 717859811..e0f5bf315 100644
--- a/uefi-test-runner/src/proto/media/known_disk.rs
+++ b/uefi-test-runner/src/proto/media/known_disk.rs
@@ -214,7 +214,7 @@ fn test_raw_disk_io2(handle: Handle, bt: &BootServices) {
             // Initialise the task context
             let mut task = DiskIoTask {
                 token: DiskIo2Token {
-                    event: event.unsafe_clone(),
+                    event: Some(event.unsafe_clone()),
                     transaction_status: uefi::Status::NOT_READY,
                 },
                 buffer: [0; 512],

From 44db75e3e31cf0fbefe721d134a0c9beed038938 Mon Sep 17 00:00:00 2001
From: Timothy Roberts <39689890+timrobertsdev@users.noreply.github.com>
Date: Wed, 12 Oct 2022 23:25:31 -0400
Subject: [PATCH 2/3] Add `Event` change to changelog. Improve `Event`
 docstring.

---
 CHANGELOG.md          | 1 +
 src/data_types/mod.rs | 4 +++-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5636458e0..596f9f465 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,7 @@
   `Address` always take a 64-bit value, regardless of target platform.
 - The conversion methods on `DevicePathToText` and `DevicePathFromText`
   now return a `uefi::Result` instead of an `Option`.
+- `Event` is now a newtype around `NonNull<c_void>` instead of `*mut c_void`.
 
 ## uefi-macros - [Unreleased]
 
diff --git a/src/data_types/mod.rs b/src/data_types/mod.rs
index 7ce404748..4505aee3c 100644
--- a/src/data_types/mod.rs
+++ b/src/data_types/mod.rs
@@ -37,7 +37,9 @@ impl Handle {
     }
 }
 
-/// Handle to an event structure
+/// Handle to an event structure, guaranteed to be non-null.
+/// 
+/// If you need to have a nullable event, use `Option<Event>`.
 #[repr(transparent)]
 pub struct Event(NonNull<c_void>);
 

From 19ecdb356d66a01913809f3f166ec3bf4878a080 Mon Sep 17 00:00:00 2001
From: Timothy Roberts <39689890+timrobertsdev@users.noreply.github.com>
Date: Mon, 17 Oct 2022 16:05:02 -0400
Subject: [PATCH 3/3] Cargo fmt for whitespace

---
 src/data_types/mod.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/data_types/mod.rs b/src/data_types/mod.rs
index 4505aee3c..987d7e95b 100644
--- a/src/data_types/mod.rs
+++ b/src/data_types/mod.rs
@@ -38,7 +38,7 @@ impl Handle {
 }
 
 /// Handle to an event structure, guaranteed to be non-null.
-/// 
+///
 /// If you need to have a nullable event, use `Option<Event>`.
 #[repr(transparent)]
 pub struct Event(NonNull<c_void>);