From 9b86132fd00e3a1558f80bae9982c4fb02f96238 Mon Sep 17 00:00:00 2001
From: "Dr. Chat" <arkolbed@gmail.com>
Date: Sat, 6 Aug 2016 18:14:26 -0500
Subject: [PATCH] Rewrite XIOCompletion::WaitForNotification

---
 src/xenia/kernel/xboxkrnl/xboxkrnl_io.cc |  4 ++--
 src/xenia/kernel/xiocompletion.cc        | 19 ++++++++-----------
 src/xenia/kernel/xiocompletion.h         |  6 ++----
 3 files changed, 12 insertions(+), 17 deletions(-)

diff --git a/src/xenia/kernel/xboxkrnl/xboxkrnl_io.cc b/src/xenia/kernel/xboxkrnl/xboxkrnl_io.cc
index f30fbf826..641de8e1e 100644
--- a/src/xenia/kernel/xboxkrnl/xboxkrnl_io.cc
+++ b/src/xenia/kernel/xboxkrnl/xboxkrnl_io.cc
@@ -368,8 +368,8 @@ dword_result_t NtRemoveIoCompletion(
   }
 
   uint64_t timeout_ticks = timeout ? static_cast<uint32_t>(*timeout) : 0u;
-  if (port->WaitForNotification(timeout_ticks)) {
-    auto notification = port->DequeueNotification();
+  XIOCompletion::IONotification notification;
+  if (port->WaitForNotification(timeout_ticks, &notification)) {
     if (key_context) {
       *key_context = notification.key_context;
     }
diff --git a/src/xenia/kernel/xiocompletion.cc b/src/xenia/kernel/xiocompletion.cc
index 4739424ba..0ccc733ed 100644
--- a/src/xenia/kernel/xiocompletion.cc
+++ b/src/xenia/kernel/xiocompletion.cc
@@ -26,20 +26,17 @@ void XIOCompletion::QueueNotification(IONotification& notification) {
   notification_semaphore_->Release(1, nullptr);
 }
 
-XIOCompletion::IONotification XIOCompletion::DequeueNotification() {
-  std::unique_lock<std::mutex> lock(notification_lock_);
-  assert_false(notifications_.empty());
-
-  auto notification = notifications_.front();
-  notifications_.pop();
-
-  return notification;
-}
-
-bool XIOCompletion::WaitForNotification(uint64_t wait_ticks) {
+bool XIOCompletion::WaitForNotification(uint64_t wait_ticks,
+                                        IONotification* notify) {
   auto ms = std::chrono::milliseconds(TimeoutTicksToMs(wait_ticks));
   auto res = threading::Wait(notification_semaphore_.get(), false, ms);
   if (res == threading::WaitResult::kSuccess) {
+    std::unique_lock<std::mutex> lock(notification_lock_);
+    assert_false(notifications_.empty());
+
+    std::memcpy(notify, &notifications_.front(), sizeof(IONotification));
+    notifications_.pop();
+
     return true;
   }
 
diff --git a/src/xenia/kernel/xiocompletion.h b/src/xenia/kernel/xiocompletion.h
index 1634f2519..f974ee4ee 100644
--- a/src/xenia/kernel/xiocompletion.h
+++ b/src/xenia/kernel/xiocompletion.h
@@ -34,11 +34,9 @@ class XIOCompletion : public XObject {
   };
 
   void QueueNotification(IONotification& notification);
-  IONotification DequeueNotification();
 
-  // If you call this and it returns true, you MUST dequeue a notification!
-  // Returns true if the wait was cancelled because a notification was queued.
-  bool WaitForNotification(uint64_t wait_ticks);
+  // Returns true if the wait ended because a notification was received.
+  bool WaitForNotification(uint64_t wait_ticks, IONotification* notify);
 
  private:
   static const uint32_t kMaxNotifications = 1024;