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