From c634c2757cfa5167140387793ad8fff09ba59752 Mon Sep 17 00:00:00 2001
From: _Redstone_c_ <myredstone1024@gmail.com>
Date: Sat, 21 Jan 2023 14:34:57 +0800
Subject: [PATCH] feat(memory): add InOutPtr and the corresponding testing

---
 .../Source/Private/Testing/MemoryTesting.cpp  | 29 +++++++
 .../Source/Public/Memory/InOutPointer.h       | 78 +++++++++++++++++++
 .../Source/Public/Testing/MemoryTesting.h     |  1 +
 3 files changed, 108 insertions(+)
 create mode 100644 Redcraft.Utility/Source/Public/Memory/InOutPointer.h

diff --git a/Redcraft.Utility/Source/Private/Testing/MemoryTesting.cpp b/Redcraft.Utility/Source/Private/Testing/MemoryTesting.cpp
index eba4618..d849f92 100644
--- a/Redcraft.Utility/Source/Private/Testing/MemoryTesting.cpp
+++ b/Redcraft.Utility/Source/Private/Testing/MemoryTesting.cpp
@@ -7,6 +7,7 @@
 #include "Memory/SharedPointer.h"
 #include "Memory/MemoryOperator.h"
 #include "Memory/ObserverPointer.h"
+#include "Memory/InOutPointer.h"
 #include "Miscellaneous/AssertionMacros.h"
 
 NAMESPACE_REDCRAFT_BEGIN
@@ -25,6 +26,7 @@ void TestMemory()
 	TestUniquePointer();
 	TestSharedPointer();
 	TestObserverPointer();
+	TestInOutPointer();
 }
 
 void TestAlignment()
@@ -1098,6 +1100,33 @@ void TestObserverPointer()
 	}
 }
 
+void TestInOutPointer()
+{
+	{
+		TUniquePtr<int64> Temp;
+		
+		[](int64** InPtr) { *InPtr = new int64; } (OutPtr(Temp));
+		always_check(Temp.IsValid());
+
+		Temp.Reset();
+		
+		[](int64** InPtr) { *InPtr = new int64; } (OutPtr(Temp, TDefaultDelete<int64>()));
+		always_check(Temp.IsValid());
+	}
+
+	{
+		TUniquePtr<int64> Temp = MakeUnique<int64>(2485800585);
+
+		[](int64** InPtr) { always_check(**InPtr == 2485800585); delete* InPtr; *InPtr = new int64; } (InOutPtr(Temp));
+		always_check(Temp.IsValid());
+
+		Temp = MakeUnique<int64>(2821859274);
+
+		[](int64** InPtr) { always_check(**InPtr == 2821859274); delete* InPtr; *InPtr = new int64; } (InOutPtr(Temp, TDefaultDelete<int64>()));
+		always_check(Temp.IsValid());
+	}
+}
+
 NAMESPACE_END(Testing)
 
 NAMESPACE_MODULE_END(Utility)
diff --git a/Redcraft.Utility/Source/Public/Memory/InOutPointer.h b/Redcraft.Utility/Source/Public/Memory/InOutPointer.h
new file mode 100644
index 0000000..8c10836
--- /dev/null
+++ b/Redcraft.Utility/Source/Public/Memory/InOutPointer.h
@@ -0,0 +1,78 @@
+#pragma once
+
+#include "CoreTypes.h"
+#include "Templates/Tuple.h"
+#include "Templates/Utility.h"
+#include "Memory/PointerTraits.h"
+#include "Templates/Noncopyable.h"
+#include "TypeTraits/TypeTraits.h"
+
+NAMESPACE_REDCRAFT_BEGIN
+NAMESPACE_MODULE_BEGIN(Redcraft)
+NAMESPACE_MODULE_BEGIN(Utility)
+
+NAMESPACE_PRIVATE_BEGIN
+
+template <typename RT, typename ST>
+using TRawPointer = TConditional<CVoid<RT>, typename TPointerTraits<TRemoveCVRef<ST>>::ElementType*, RT>;
+
+template <bool bEnableInput, typename RT, typename ST, typename... Ts>
+class FInOutPtr final : private FSingleton
+{
+public:
+
+	explicit FInOutPtr(ST& InPtr, Ts&&... Args) requires (!bEnableInput)
+		: SPointer(InPtr), Tuple(nullptr, Forward<Ts>(Args)...)
+	{ }
+
+	explicit FInOutPtr(ST& InPtr, Ts&&... Args) requires (bEnableInput)
+		: SPointer(InPtr), Tuple(InPtr.Release(), Forward<Ts>(Args)...)
+	{ }
+
+	~FInOutPtr()
+	{
+		if constexpr (requires(RT* RPtr, ST& SPtr, Ts&&... Args) { SPtr.Reset(RPtr, Forward<Ts>(Args)...); })
+		{
+			Tuple.Apply([this](Ts&&... Args) { SPointer.Reset(Forward<Ts>(Args)...); });
+		}
+		else if constexpr (CConstructibleFrom<ST, RT, Ts...> && CMoveAssignable<ST>)
+		{
+			SPointer = Tuple.template Construct<ST>();
+		}
+		else check_no_entry();
+	}
+
+	operator    RT*()                                { return &Tuple.First; }
+	operator void**() requires (!CSameAs<void*, RT>) { return &Tuple.First; }
+
+private:
+
+	ST& SPointer;
+	TTuple< RT, Ts&&...> Tuple;
+
+};
+
+NAMESPACE_PRIVATE_END
+
+template <typename RT = void, typename ST, typename... Ts> requires ((CVoid<RT>) || (CPointer<RT>)
+	&& (requires(NAMESPACE_PRIVATE::TRawPointer<RT, ST>* RPtr, ST& SPtr, Ts&&... Args) { SPtr.Reset(RPtr, Forward<Ts>(Args)...); })
+	|| (CConstructibleFrom<ST, NAMESPACE_PRIVATE::TRawPointer<RT, ST>, Ts...> && CMoveAssignable<ST>)
+	&& requires { typename TPointerTraits<TRemoveCV<ST>>::ElementType; })
+auto OutPtr(ST& InPtr, Ts&&... Args)
+{
+	return NAMESPACE_PRIVATE::FInOutPtr<false, NAMESPACE_PRIVATE::TRawPointer<RT, ST>, ST, Ts...>(InPtr, Forward<Ts>(Args)...);
+}
+
+template <typename RT = void, typename ST, typename... Ts> requires ((CVoid<RT>) || (CPointer<RT>)
+	&& (requires(NAMESPACE_PRIVATE::TRawPointer<RT, ST>* RPtr, ST& SPtr, Ts&&... Args) { SPtr.Reset(RPtr, Forward<Ts>(Args)...); })
+	|| (CConstructibleFrom<ST, NAMESPACE_PRIVATE::TRawPointer<RT, ST>, Ts...> && CMoveAssignable<ST>)
+	&& requires(ST& SPtr) { { SPtr.Release() } -> CConvertibleTo<NAMESPACE_PRIVATE::TRawPointer<RT, ST>>; }
+	&& requires { typename TPointerTraits<TRemoveCV<ST>>::ElementType; })
+auto InOutPtr(ST& InPtr, Ts&&... Args)
+{
+	return NAMESPACE_PRIVATE::FInOutPtr<true, NAMESPACE_PRIVATE::TRawPointer<RT, ST>, ST, Ts...>(InPtr, Forward<Ts>(Args)...);
+}
+
+NAMESPACE_MODULE_END(Utility)
+NAMESPACE_MODULE_END(Redcraft)
+NAMESPACE_REDCRAFT_END
diff --git a/Redcraft.Utility/Source/Public/Testing/MemoryTesting.h b/Redcraft.Utility/Source/Public/Testing/MemoryTesting.h
index 344eac9..f4fb660 100644
--- a/Redcraft.Utility/Source/Public/Testing/MemoryTesting.h
+++ b/Redcraft.Utility/Source/Public/Testing/MemoryTesting.h
@@ -17,6 +17,7 @@ REDCRAFTUTILITY_API void TestPointerTraits();
 REDCRAFTUTILITY_API void TestUniquePointer();
 REDCRAFTUTILITY_API void TestSharedPointer();
 REDCRAFTUTILITY_API void TestObserverPointer();
+REDCRAFTUTILITY_API void TestInOutPointer();
 
 NAMESPACE_END(Testing)