From bd4b05e534e629bd6f0980f75a93f8e85ee184e2 Mon Sep 17 00:00:00 2001
From: apio <blobs.trading@gmail.com>
Date: Fri, 23 Dec 2022 10:23:13 +0100
Subject: [PATCH] Add OwnedPtr and SharedPtr

---
 luna/include/luna/OwnedPtr.h  |  61 ++++++++++++++++++++
 luna/include/luna/SharedPtr.h | 104 ++++++++++++++++++++++++++++++++++
 2 files changed, 165 insertions(+)
 create mode 100644 luna/include/luna/OwnedPtr.h
 create mode 100644 luna/include/luna/SharedPtr.h

diff --git a/luna/include/luna/OwnedPtr.h b/luna/include/luna/OwnedPtr.h
new file mode 100644
index 00000000..cc147f24
--- /dev/null
+++ b/luna/include/luna/OwnedPtr.h
@@ -0,0 +1,61 @@
+#pragma once
+#include <luna/Alloc.h>
+#include <luna/Result.h>
+
+template <typename T> class OwnedPtr
+{
+  public:
+    OwnedPtr(T* ptr)
+    {
+        m_ptr = ptr;
+    }
+
+    ~OwnedPtr()
+    {
+        if (m_ptr) delete m_ptr;
+    }
+
+    OwnedPtr(const OwnedPtr<T>& other) = delete;
+
+    OwnedPtr(OwnedPtr<T>&& other)
+    {
+        m_ptr = other.m_ptr;
+        other.m_ptr = nullptr;
+    }
+
+    T* ptr() const
+    {
+        return m_ptr;
+    }
+
+    T* operator->() const
+    {
+        return m_ptr;
+    }
+
+    T& operator*() const
+    {
+        return *m_ptr;
+    }
+
+  private:
+    T* m_ptr;
+};
+
+template <typename T, class... Args> Result<OwnedPtr<T>> make_owned(Args... args)
+{
+    T* raw = TRY(make<T>(args...));
+    return OwnedPtr<T> { raw };
+}
+
+template <typename T> OwnedPtr<T> adopt_owned(T* ptr)
+{
+    return OwnedPtr<T> { ptr };
+}
+
+template <typename T> Result<OwnedPtr<T>> adopt_owned_if_nonnull(T* ptr)
+{
+    if (ptr) return OwnedPtr<T> { ptr };
+    else
+        return err(ENOMEM);
+}
\ No newline at end of file
diff --git a/luna/include/luna/SharedPtr.h b/luna/include/luna/SharedPtr.h
new file mode 100644
index 00000000..08c09931
--- /dev/null
+++ b/luna/include/luna/SharedPtr.h
@@ -0,0 +1,104 @@
+#pragma once
+#include <luna/Alloc.h>
+#include <luna/Atomic.h>
+#include <luna/DebugLog.h>
+#include <luna/Result.h>
+#include <luna/ScopeGuard.h>
+
+namespace __detail
+{
+    struct RefCount
+    {
+        void ref()
+        {
+            m_ref_count++;
+        }
+
+        bool unref()
+        {
+            m_ref_count--;
+            return m_ref_count == 0;
+        }
+
+      private:
+        Atomic<int> m_ref_count { 1 };
+    };
+}
+
+template <typename T> class SharedPtr
+{
+    using RefCount = __detail::RefCount;
+
+  public:
+    SharedPtr(T* ptr, RefCount* ref_count) : m_ptr(ptr), m_ref_count(ref_count)
+    {
+    }
+
+    SharedPtr(const SharedPtr<T>& other) : m_ptr(other.m_ptr), m_ref_count(other.m_ref_count)
+    {
+        m_ref_count->ref();
+    }
+
+    SharedPtr(SharedPtr<T>&& other) : m_ptr(other.m_ptr), m_ref_count(other.m_ref_count)
+    {
+        other.m_ptr = nullptr;
+        other.m_ref_count = nullptr;
+    }
+
+    ~SharedPtr()
+    {
+        if (m_ref_count && m_ref_count->unref())
+        {
+            delete m_ref_count;
+            delete m_ptr;
+        }
+    }
+
+    T* ptr() const
+    {
+        return m_ptr;
+    }
+
+    T* operator->() const
+    {
+        return m_ptr;
+    }
+
+    T& operator*() const
+    {
+        return *m_ptr;
+    }
+
+  private:
+    T* m_ptr;
+    RefCount* m_ref_count;
+};
+
+template <typename T, class... Args> Result<SharedPtr<T>> make_shared(Args... args)
+{
+    using RefCount = __detail::RefCount;
+
+    RefCount* ref_count = TRY(make<RefCount>());
+    auto guard = make_scope_guard([&] { delete ref_count; });
+
+    T* ptr = TRY(make<T>(args...));
+    guard.deactivate();
+
+    return SharedPtr<T> { ptr, ref_count };
+}
+
+template <typename T> Result<SharedPtr<T>> adopt_shared(T* ptr)
+{
+    using RefCount = __detail::RefCount;
+
+    RefCount* ref_count = TRY(make<RefCount>());
+
+    return SharedPtr<T> { ptr, ref_count };
+}
+
+template <typename T> Result<SharedPtr<T>> adopt_shared_if_nonnull(T* ptr)
+{
+    if (ptr) return adopt_shared(ptr);
+    else
+        return err(ENOMEM);
+}
\ No newline at end of file