feat(templates): add TScopeCallback TGuardValue and TScopeCounter

This commit is contained in:
_Redstone_c_ 2023-01-02 21:49:24 +08:00
parent 38ec8f6571
commit e057cdc84d
4 changed files with 223 additions and 0 deletions

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@ -24,6 +24,7 @@ void TestTemplates()
TestTuple();
TestFunction();
TestAtomic();
TestScopeHelper();
TestMiscTemplates();
}
@ -1381,6 +1382,93 @@ void TestAtomic()
}
}
void TestScopeHelper()
{
{
int32 CheckNum = 0;
{
TScopeCallback ScopeCallback([&]() { CheckNum = 2; });
always_check(CheckNum == 0);
CheckNum = 1;
always_check(CheckNum == 1);
}
always_check(CheckNum == 2);
}
{
int32 CheckNum = 0;
{
TScopeCallback ScopeCallback([&]() { CheckNum = 2; });
always_check(CheckNum == 0);
CheckNum = 1;
always_check(CheckNum == 1);
ScopeCallback.Release();
}
always_check(CheckNum == 1);
}
{
int32 CheckNum = 0;
{
TScopeCallback ScopeCallbackA([&]() { CheckNum = 2; });
TScopeCallback ScopeCallbackB(MoveTemp(ScopeCallbackA));
always_check(CheckNum == 0);
CheckNum = 1;
always_check(CheckNum == 1);
}
always_check(CheckNum == 2);
}
{
int32 CheckNum = 1;
{
TGuardValue GuardValue(CheckNum);
CheckNum = 2;
always_check(CheckNum == 2);
}
always_check(CheckNum == 1);
}
{
int32 CheckNum = 1;
{
TGuardValue GuardValue(CheckNum, 2);
always_check(CheckNum == 2);
}
always_check(CheckNum == 1);
}
{
int32 CheckNum = 1;
{
TGuardValue GuardValue(CheckNum, 2);
always_check(CheckNum == 2);
GuardValue.Release();
}
always_check(CheckNum == 2);
}
{
int32 CheckNum = 1;
{
TGuardValue GuardValueA(CheckNum, 2);
TGuardValue GuardValueB(MoveTemp(GuardValueA));
always_check(CheckNum == 2);
}
always_check(CheckNum == 1);
}
{
int32 CheckNum = 1;
{
TScopeCounter GuardValue(CheckNum);
always_check(CheckNum == 2);
}
always_check(CheckNum == 1);
}
}
NAMESPACE_UNNAMED_BEGIN
template <typename T>

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@ -0,0 +1,133 @@
#pragma once
#include "CoreTypes.h"
#include "Templates/Utility.h"
#include "TypeTraits/Invocable.h"
#include "Templates/Noncopyable.h"
#include "TypeTraits/CompositeType.h"
#include "TypeTraits/Miscellaneous.h"
#include "TypeTraits/SupportedOperations.h"
NAMESPACE_REDCRAFT_BEGIN
NAMESPACE_MODULE_BEGIN(Redcraft)
NAMESPACE_MODULE_BEGIN(Utility)
/** The class template is a general-purpose scope guard intended to call its callback function when a scope is exited. */
template <CInvocable F> requires (CDestructible<F>)
class TScopeCallback final : public FNoncopyable
{
public:
/** Initializes the callback function with a function or function object. */
template <typename InF> requires (!CSameAs<TRemoveCVRef<InF>, TScopeCallback> && CConstructibleFrom<F, InF>)
FORCEINLINE constexpr explicit TScopeCallback(InF&& Func) : Storage(Forward<InF>(Func)), bIsActive(true) { }
/** Move constructor. Initializes the stored object with the one in other. */
FORCEINLINE constexpr TScopeCallback(TScopeCallback&& InValue) requires (CMoveConstructible<F>)
: Storage(MoveTemp(InValue.Storage)), bIsActive(InValue.bIsActive)
{
InValue.Release();
}
/** Calls the callback function if the TScopeCallback is active, then destroys the stored object. */
FORCEINLINE constexpr ~TScopeCallback()
{
if (bIsActive) Storage();
}
/** Makes the TScopeCallback inactive. */
FORCEINLINE constexpr void Release() { bIsActive = false; }
/** @return a const reference to the stored object. */
FORCEINLINE constexpr const F& Get() const { return Storage; }
private:
F Storage;
bool bIsActive;
};
template <typename F>
TScopeCallback(F) -> TScopeCallback<F>;
/** The class template is a general-purpose scope guard intended to make sure a value is restored when a scope is exited. */
template <typename T> requires (CCopyConstructible<T> && CCopyAssignable<T> && CMoveAssignable<T> && CDestructible<T>)
class TGuardValue final : public FNoncopyable
{
public:
/** Initializes the TGuardValue with a reference. */
FORCEINLINE constexpr TGuardValue(T& InReference) : Reference(InReference), OldValue(InReference), bIsActive(true) { }
/** Initializes the TGuardValue with a reference and assign a new value to the reference. */
template <typename U> requires (CAssignableFrom<T&, U>)
FORCEINLINE constexpr TGuardValue(T& InReference, U&& InValue) : Reference(InReference), OldValue(InReference), bIsActive(true) { InReference = InValue; }
/** Move constructor. Initializes the referenced value and old value with the one in other. */
FORCEINLINE constexpr TGuardValue(TGuardValue&& InValue) requires (CMoveConstructible<T>)
: Reference(InValue.Reference), OldValue(MoveTemp(InValue.OldValue)), bIsActive(InValue.bIsActive)
{
InValue.Release();
}
/** Restore the referenced value if the TGuardValue is active, then destroys the old value. */
FORCEINLINE constexpr ~TGuardValue()
{
if (bIsActive) Reference = MoveTemp(OldValue);
}
/** Makes the TGuardValue inactive. */
FORCEINLINE constexpr void Release() { bIsActive = false; }
/** @return a const reference to the old value. */
FORCEINLINE constexpr const T& Get() const { return OldValue; }
private:
T& Reference;
T OldValue;
bool bIsActive;
};
template <typename T>
TGuardValue(T&) -> TGuardValue<T>;
template <typename T, typename U>
TGuardValue(T&, U&&) -> TGuardValue<T>;
/** Commonly used to make sure a value is incremented, and then decremented when a scope is exited. */
template <typename T> requires (requires(T& Value) { ++Value; --Value; })
class TScopeCounter : public FNoncopyable
{
public:
/** Initializes the TScopeCounter with a reference and increments it. */
FORCEINLINE constexpr TScopeCounter(T& InReference)
: Reference(InReference)
{
++Reference;
}
/** Decrements the referenced value. */
FORCEINLINE constexpr ~TScopeCounter()
{
--Reference;
}
/** @return a const reference to the value. */
FORCEINLINE constexpr const T& Get() const { return Reference; }
private:
T& Reference;
};
template <typename T>
TScopeCounter(T&) -> TScopeCounter<T>;
NAMESPACE_MODULE_END(Utility)
NAMESPACE_MODULE_END(Redcraft)
NAMESPACE_REDCRAFT_END

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@ -14,3 +14,4 @@
#include "Templates/TypeHash.h"
#include "Templates/Function.h"
#include "Templates/Atomic.h"
#include "Templates/ScopeHelper.h"

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@ -17,6 +17,7 @@ REDCRAFTUTILITY_API void TestAny();
REDCRAFTUTILITY_API void TestTuple();
REDCRAFTUTILITY_API void TestFunction();
REDCRAFTUTILITY_API void TestAtomic();
REDCRAFTUTILITY_API void TestScopeHelper();
REDCRAFTUTILITY_API void TestMiscTemplates();
NAMESPACE_END(Testing)