Conditions.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "DataStorage/CommonTypes.h"
#include "Templates/SubclassOf.h"
#include "UObject/WeakObjectPtrTemplates.h"
 
class UScriptStruct;
 
namespace UE::Editor::DataStorage
{
    class ICoreProvider;
 
namespace Queries
{
    struct FColumnBase
    {
        TWeakObjectPtr<const UScriptStruct> TypeInfo = nullptr;
        FName Identifier = NAME_None;
 
    protected:
        FColumnBase() = default;
        constexpr explicit FColumnBase(TWeakObjectPtr<const UScriptStruct> ColumnTypeInfo, const FName& InIdentifier)
            : TypeInfo(ColumnTypeInfo)
            , Identifier(InIdentifier)
        {}
    };
 
    template<typename T = void>
    struct TColumn final : public FColumnBase
    {
        template <typename U = T> requires (!std::is_same_v<U, void>)
            constexpr explicit TColumn(const FName& Identifier = NAME_None) : FColumnBase(T::StaticStruct(), Identifier) {}
        
        template <typename U = T> requires (std::is_same_v<U, void>)
            constexpr explicit TColumn(TWeakObjectPtr<const UScriptStruct> ColumnTypeInfo, const FName& Identifier = NAME_None)
                : FColumnBase(ColumnTypeInfo, Identifier)
        {}
    };
 
    /*
     * Compile Context used to resolve dynamic columns when FConditions are compiled
     */
    class IQueryConditionCompileContext 
    {
    public:
        virtual ~IQueryConditionCompileContext() = default;
        virtual const UScriptStruct* GenerateDynamicColumn(const FDynamicColumnDescription&) const = 0;
    };
 
    /*
     * Specialized compile context that accepts an ICoreProvider
     */
    class FEditorStorageQueryConditionCompileContext : public IQueryConditionCompileContext 
    {
    public:
        TYPEDELEMENTFRAMEWORK_API explicit FEditorStorageQueryConditionCompileContext(ICoreProvider* InDataStorage);
        TYPEDELEMENTFRAMEWORK_API virtual const UScriptStruct* GenerateDynamicColumn(const FDynamicColumnDescription& Description) const override;
        
    private:
        ICoreProvider* DataStorage;
    };
 
 
    class FConditions final
    {
    public:
        using ContainsCallback = TFunctionRef<bool(uint8_t ColumnIndex, TWeakObjectPtr<const UScriptStruct> Column)>;
 
        TYPEDELEMENTFRAMEWORK_API friend FConditions operator&&(const FConditions& Lhs, FColumnBase Rhs);
        TYPEDELEMENTFRAMEWORK_API friend FConditions operator&&(const FConditions& Lhs, const FConditions& Rhs);
        TYPEDELEMENTFRAMEWORK_API friend FConditions operator&&(FColumnBase Lhs, FColumnBase Rhs);
        TYPEDELEMENTFRAMEWORK_API friend FConditions operator&&(FColumnBase Lhs, const FConditions& Rhs);
 
        TYPEDELEMENTFRAMEWORK_API friend FConditions operator||(const FConditions& Lhs, FColumnBase Rhs);
        TYPEDELEMENTFRAMEWORK_API friend FConditions operator||(const FConditions& Lhs, const FConditions& Rhs);
        TYPEDELEMENTFRAMEWORK_API friend FConditions operator||(FColumnBase Lhs, FColumnBase Rhs);
        TYPEDELEMENTFRAMEWORK_API friend FConditions operator||(FColumnBase Lhs, const FConditions& Rhs);
 
        TYPEDELEMENTFRAMEWORK_API FConditions();
        // Not marked as "explicit" to allow conversion from a column. This means that conditions with a single
        // argument can be written in the same way as ones that use combinations.
        TYPEDELEMENTFRAMEWORK_API FConditions(FColumnBase Column);
 
        // Compile must be called before using any functions that access the columns
        TYPEDELEMENTFRAMEWORK_API FConditions& Compile(const IQueryConditionCompileContext& CompileContext);
 
        // Check whether these query conditions have been compiled
        TYPEDELEMENTFRAMEWORK_API bool IsCompiled() const;
 
        TYPEDELEMENTFRAMEWORK_API void AppendToString(FString& Output) const;
 
        TYPEDELEMENTFRAMEWORK_API bool Verify(TConstArrayView<FColumnBase> AvailableColumns) const;
        TYPEDELEMENTFRAMEWORK_API bool Verify(
            TArray<TWeakObjectPtr<const UScriptStruct>>& MatchedColumns,
            TConstArrayView<FColumnBase> AvailableColumns,
            bool AvailableColumnsAreSorted = false) const;
        TYPEDELEMENTFRAMEWORK_API bool Verify(TConstArrayView<TWeakObjectPtr<const UScriptStruct>> AvailableColumns,
            bool AvailableColumnsAreSorted = false) const;
        TYPEDELEMENTFRAMEWORK_API bool Verify(
            TArray<TWeakObjectPtr<const UScriptStruct>>& MatchedColumns,
            TConstArrayView<TWeakObjectPtr<const UScriptStruct>> AvailableColumns,
            bool AvailableColumnsAreSorted = false) const;
        TYPEDELEMENTFRAMEWORK_API bool Verify(TSet<TWeakObjectPtr<const UScriptStruct>> AvailableColumns) const;
        TYPEDELEMENTFRAMEWORK_API bool Verify(ContainsCallback Callback) const;
 
        TYPEDELEMENTFRAMEWORK_API uint8_t MinimumColumnMatchRequired() const;
        TYPEDELEMENTFRAMEWORK_API TConstArrayView<TWeakObjectPtr<const UScriptStruct>> GetColumns() const;
        TYPEDELEMENTFRAMEWORK_API bool IsEmpty() const;
        TYPEDELEMENTFRAMEWORK_API bool UsesDynamicTemplates() const;
 
    private:
        template<typename AvailableColumnType, typename ProjectionFunction>
        bool VerifyWithDynamicColumn(TConstArrayView<AvailableColumnType> AvailableColumns, uint64& OutMatches, ProjectionFunction Projection) const;
        
        void AppendName(FString& Output, TWeakObjectPtr<const UScriptStruct> TypeInfo) const;
 
        bool EntersScopeNext(uint8_t Index) const;
        bool EntersScope(uint8_t Index) const;
        bool Contains(TWeakObjectPtr<const UScriptStruct> ColumnType, const TArray<FColumnBase>& AvailableColumns) const;
 
        bool VerifyBootstrap(ContainsCallback Contains) const;
        bool VerifyRange(uint8_t& TokenIndex, uint8_t& ColumnIndex, ContainsCallback Contains) const;
 
        void ConvertColumnBitToArray(TArray<TWeakObjectPtr<const UScriptStruct>>& MatchedColumns, uint64 ColumnBits) const;
 
        uint8_t MinimumColumnMatchRequiredRange(uint8_t& Front) const;
 
        static void AppendQuery(FConditions& Target, const FConditions& Source);
 
        static constexpr SIZE_T MaxColumnCount = 32;
        static constexpr SIZE_T MaxTokenCount = 64;
 
        enum class Token : uint8_t
        {
            None,
            And,
            Or,
            ScopeOpen,
            ScopeClose
        };
 
        enum class EColumnFlags : uint8_t
        {
            DynamicColumnTemplate = 1 << 0
        };
        FRIEND_ENUM_CLASS_FLAGS(EColumnFlags);
        
        using ColumnArray = TArray<TWeakObjectPtr<const UScriptStruct>, TInlineAllocator<MaxColumnCount>>;
        using TokenArray = TArray<Token, TInlineAllocator<MaxTokenCount>>;
        using IdentifierArray = TArray<FName, TInlineAllocator<MaxColumnCount>>;
        using ColumnFlagArray = TArray<EColumnFlags, TInlineAllocator<MaxColumnCount>>;
 
        ColumnArray Columns;
        ColumnFlagArray ColumnFlags;
        TokenArray Tokens;
        IdentifierArray Identifiers;
        uint8_t ColumnCount = 0;
        uint8_t TokenCount = 0;
        bool bIsCompiled = false;
    };
 
    TYPEDELEMENTFRAMEWORK_API FConditions operator&&(const FConditions& Lhs, FColumnBase Rhs);
    TYPEDELEMENTFRAMEWORK_API FConditions operator&&(const FConditions& Lhs, const FConditions& Rhs);
    TYPEDELEMENTFRAMEWORK_API FConditions operator&&(FColumnBase Lhs, FColumnBase Rhs);
    TYPEDELEMENTFRAMEWORK_API FConditions operator&&(FColumnBase Lhs, const FConditions& Rhs);
 
    TYPEDELEMENTFRAMEWORK_API FConditions operator||(const FConditions& Lhs, FColumnBase Rhs);
    TYPEDELEMENTFRAMEWORK_API FConditions operator||(const FConditions& Lhs, const FConditions& Rhs);
    TYPEDELEMENTFRAMEWORK_API FConditions operator||(FColumnBase Lhs, FColumnBase Rhs);
    TYPEDELEMENTFRAMEWORK_API FConditions operator||(FColumnBase Lhs, const FConditions& Rhs);
} // namespace Queries
} // namespace UE::Editor::DataStorage