EM_Task/CoreUObject/Private/UObject/PropertyStr.cpp

// Copyright Epic Games, Inc. All Rights Reserved.

#include "CoreMinimal.h"
#include "UObject/ObjectMacros.h"
#include "UObject/PropertyPortFlags.h"
#include "UObject/UnrealType.h"
#include "Misc/StringBuilder.h"
#include "Misc/AsciiSet.h"

/*-----------------------------------------------------------------------------
        FStrProperty.
-----------------------------------------------------------------------------*/
IMPLEMENT_FIELD(FStrProperty)

EConvertFromTypeResult FStrProperty::ConvertFromType(const FPropertyTag& Tag, FStructuredArchive::FSlot Slot, uint8* Data, UStruct* DefaultsStruct)
{
    // Convert serialized text to string.
    if (Tag.Type == NAME_TextProperty)
    {
        FText Text;
        Slot << Text;
        const FString String = FTextInspector::GetSourceString(Text) ? *FTextInspector::GetSourceString(Text) : TEXT("");
        SetPropertyValue_InContainer(Data, String, Tag.ArrayIndex);

        return EConvertFromTypeResult::Converted;
    }

    return EConvertFromTypeResult::UseSerializeItem;
}

FString FStrProperty::GetCPPTypeForwardDeclaration() const
{
    return FString();
}

// Necessary to fix Compiler Error C2026 and C1091
FString FStrProperty::ExportCppHardcodedText(const FString& InSource, const FString& Indent)
{
    constexpr FAsciiSet EscapableCharacters("\\\"\n\r\t");

    auto EstimateExportedStringLength = [&EscapableCharacters](const UTF16CHAR* InStr)
    {
        int32 EstimatedLen = 0;
        while (const UTF16CHAR Char = *InStr++)
        {
            if (EscapableCharacters.Contains(Char))
            {
                // Exported escaped
                EstimatedLen += 2;
            }
            else if (Char > 0x7f)
            {
                // Exported as a UTF-16 sequence
                EstimatedLen += 4;
            }
            else
            {
                // Exported verbatim
                EstimatedLen += 1;
            }
        }
        return EstimatedLen;
    };

    const int32 PreferredLineSize = 256;
    const int32 LinesPerString    = 16;

    // Note: This is a no-op on platforms that are using a 16-bit TCHAR
    FTCHARToUTF16 UTF16SourceString(*InSource, InSource.Len() + 1);  // include the null terminator

    const bool bUseSubStrings = EstimateExportedStringLength(UTF16SourceString.Get()) > (LinesPerString * PreferredLineSize);
    int32 LineNum             = 0;

    TStringBuilder<1024> Result;

    if (bUseSubStrings)
    {
        Result << TEXT("*(FString(");
    }

    const UTF16CHAR* SourceBegin = UTF16SourceString.Get();
    const UTF16CHAR* SourceIt    = SourceBegin;
    do
    {
        if (SourceIt > SourceBegin)
        {
            Result << TEXT("\n");
            Result << Indent;
        }

        ++LineNum;
        if (bUseSubStrings && (LineNum % LinesPerString) == 0)
        {
            Result << TEXT(") + FString(");
        }

        Result << TEXT("TEXT(\"");
        {
            int32 ResultStartLen = Result.Len();
            while (*SourceIt && (Result.Len() - ResultStartLen) < PreferredLineSize)
            {
                if (EscapableCharacters.Contains(*SourceIt))
                {
                    const TCHAR CharToEscape = (TCHAR)*SourceIt++;

                    Result << TEXT('\\');
                    switch (CharToEscape)
                    {
                        case TEXT('\n'):
                            Result << TEXT('n');
                            break;
                        case TEXT('\r'):
                            Result << TEXT('r');
                            break;
                        case TEXT('\t'):
                            Result << TEXT('t');
                            break;
                        default:
                            Result << CharToEscape;
                            break;
                    }
                }
                else if (*SourceIt > 0x7f)
                {
                    // If this character is part of a surrogate pair, then combine them and write them as a single UTF-32 sequence
                    // Otherwise just write out the character as a UTF-16 sequence
                    if (StringConv::IsHighSurrogate(*SourceIt) && StringConv::IsLowSurrogate(*(SourceIt + 1)))
                    {
                        const UTF32CHAR Codepoint = StringConv::EncodeSurrogate(*SourceIt, *(SourceIt + 1));
                        Result.Appendf(TEXT("\\U%08x"), Codepoint);
                        SourceIt += 2;
                    }
                    else
                    {
                        Result.Appendf(TEXT("\\u%04x"), *SourceIt++);
                    }
                }
                else
                {
                    Result << (TCHAR)*SourceIt++;
                }
            }
        }
        Result << TEXT("\")");
    } while (*SourceIt);

    if (bUseSubStrings)
    {
        Result << TEXT("))");
    }

    return Result.ToString();
}

void FStrProperty::ExportTextItem(FString& ValueStr, const void* PropertyValue, const void* DefaultValue, UObject* Parent, int32 PortFlags, UObject* ExportRootScope) const
{
    FString& StringValue = *(FString*)PropertyValue;
    if (0 != (PortFlags & PPF_ExportCpp))
    {
        ValueStr += FString::Printf(TEXT("FString(%s)"), *ExportCppHardcodedText(StringValue, FString()));
    }
    else if (!(PortFlags & PPF_Delimited))
    {
        ValueStr += StringValue;
    }
    else if (StringValue.Len() > 0)
    {
        ValueStr += FString::Printf(TEXT("\"%s\""), *(StringValue.ReplaceCharWithEscapedChar()));
    }
    else
    {
        ValueStr += TEXT("\"\"");
    }
}
const TCHAR* FStrProperty::ImportText_Internal(const TCHAR* Buffer, void* Data, int32 PortFlags, UObject* Parent, FOutputDevice* ErrorText) const
{
    if (!(PortFlags & PPF_Delimited))
    {
        *(FString*)Data = Buffer;

        // in order to indicate that the value was successfully imported, advance the buffer past the last character that was imported
        Buffer += FCString::Strlen(Buffer);
    }
    else
    {
        // require quoted string here
        if (*Buffer != TCHAR('"'))
        {
            ErrorText->Logf(TEXT("Missing opening '\"' in string property value: %s"), Buffer);
            return NULL;
        }
        const TCHAR* Start = Buffer;
        FString Temp;
        Buffer = FPropertyHelpers::ReadToken(Buffer, Temp);
        if (Buffer == NULL)
        {
            return NULL;
        }
        if (Buffer > Start && Buffer[-1] != TCHAR('"'))
        {
            ErrorText->Logf(TEXT("Missing terminating '\"' in string property value: %s"), Start);
            return NULL;
        }
        *(FString*)Data = MoveTemp(Temp);
    }
    return Buffer;
}

uint32 FStrProperty::GetValueTypeHashInternal(const void* Src) const
{
    return GetTypeHash(*(const FString*)Src);
}