Kernel+LibC: Turn errno codes into a strongly typed enum

..and allow implicit creation of KResult and KResultOr from ErrnoCode.
This means that kernel functions that return those types can finally
do "return EINVAL;" and it will just work.

There's a handful of functions that still deal with signed integers
that should be converted to return KResults.

1 files changed, 10 insertions, 3 deletions

diff --git a/Kernel/KResult.h b/Kernel/KResult.h
index 2629b25551..48e348b9fa 100644
--- a/Kernel/KResult.h
+++ b/Kernel/KResult.h
@@ -27,6 +27,8 @@
 #pragma once
 
 #include <AK/Assertions.h>
+#include <AK/Platform.h>
+#include <AK/StdLibExtras.h>
 #include <LibC/errno_numbers.h>
 
 namespace Kernel {
@@ -37,10 +39,9 @@ enum KSuccessTag {
 
 class [[nodiscard]] KResult {
 public:
-    ALWAYS_INLINE explicit KResult(int negative_e)
-        : m_error(negative_e)
+    KResult(ErrnoCode error)
+        : m_error(-error)
     {
-        ASSERT(negative_e <= 0);
     }
     KResult(KSuccessTag)
         : m_error(0)
@@ -69,6 +70,12 @@ public:
     {
     }
 
+    KResultOr(ErrnoCode error)
+        : m_error(error)
+        , m_is_error(true)
+    {
+    }
+
     ALWAYS_INLINE KResultOr(T&& value)
     {
         new (&m_storage) T(move(value));