Kernel: Introduce contended and locked resource concepts

Author: https://github.com/boricj
Commit: https://github.com/SerenityOS/serenity/commit/3d684316c2d
Pull-request: https://github.com/SerenityOS/serenity/pull/8851
Reviewed-by: https://github.com/awesomekling ✅
Reviewed-by: https://github.com/bgianfo

Kernel/Locking/ContendedResource.h

@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 2021, the SerenityOS developers.
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/StdLibExtras.h>
+#include <Kernel/Locking/Mutex.h>
+
+namespace Kernel {
+
+template<typename T, LockMode LockingMode>
+class LockedResource {
+    AK_MAKE_NONCOPYABLE(LockedResource);
+
+public:
+    LockedResource(T* value, Mutex& mutex)
+        : m_value(value)
+        , m_mutex_locker(mutex, LockingMode)
+    {
+    }
+
+    ALWAYS_INLINE T const* operator->() const { return m_value; }
+    ALWAYS_INLINE T const& operator*() const { return *m_value; }
+
+    ALWAYS_INLINE T* operator->() requires(!IsConst<T>) { return m_value; }
+    ALWAYS_INLINE T& operator*() requires(!IsConst<T>) { return *m_value; }
+
+    ALWAYS_INLINE T const* get() const { return m_value; }
+    ALWAYS_INLINE T* get() requires(!IsConst<T>) { return m_value; }
+
+private:
+    T* m_value;
+    MutexLocker m_mutex_locker;
+};
+
+class ContendedResource {
+    template<typename, LockMode>
+    friend class LockedResource;
+
+    AK_MAKE_NONCOPYABLE(ContendedResource);
+    AK_MAKE_NONMOVABLE(ContendedResource);
+
+public:
+    ContendedResource() = default;
+
+protected:
+    mutable Mutex m_mutex;
+};
+
+}