RapidJsonPluginLoading.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "JsonUtils/RapidJsonUtils.h"
#include "JsonUtils/JsonConversion.h"
#include "Internationalization/Text.h"
 
struct FLocalizationTargetDescriptor;
struct FModuleDescriptor;
struct FPluginDescriptor;
struct FCustomBuildSteps;
struct FPluginReferenceDescriptor;
struct FPluginDisallowedDescriptor;
struct FPluginManifest;
 
namespace UE {
namespace Projects {
namespace Private {
 
bool TryGetBoolField(Json::FConstObject Object, const TCHAR* FieldName, bool& Out);
bool TryGetNumberField(Json::FConstObject Object, const TCHAR* FieldName, int32& Out);
bool TryGetNumberField(Json::FConstObject Object, const TCHAR* FieldName, uint32& Out);
bool TryGetStringField(Json::FConstObject Object, const TCHAR* FieldName, FString& Out);
bool TryGetStringField(Json::FConstObject Object, const TCHAR* FieldName, FStringView& Out);
bool TryGetStringArrayField(Json::FConstObject Object, const TCHAR* FieldName, TArray<FString>& Out);
bool TryGetStringArrayField(Json::FConstObject Object, const TCHAR* FieldName, TArray<FName>& Out); 
 
bool TryGetStringArrayFieldWithDeprecatedFallback(Json::FConstObject Object, const TCHAR* FieldName, const TCHAR* DeprecatedFieldName, TArray<FString>& OutArray);
 
FText GetArrayObjectTypeError(const TCHAR* FieldName, int32 Index);
FText GetArrayObjectChildParseError(const TCHAR* FieldName, int32 Index, const FText& PropagateError);
 
 
template<typename TEnum>
inline bool TryGetEnumArrayField(Json::FConstObject Object, const TCHAR* FieldName, TArray<TEnum>& OutArray)
{
    TOptional<Json::FConstArray> Array = Json::GetArrayField(Object, FieldName);
    if (!Array.IsSet())
    {
        return false;
    }
 
    OutArray.Reset(Array->Size());
    for (const Json::FValue& JsonValue : *Array)
    {
        if (!JsonValue.IsString())
        {
            continue;
        }
 
        TEnum Value;
        if (LexTryParseString(Value, JsonValue.GetString()))
        {
            OutArray.Add(Value);
        }
    }
    return true;
}
 
template<typename TEnum>
inline bool TryGetEnumArrayFieldWithDeprecatedFallback(Json::FConstObject Object, const TCHAR* FieldName, const TCHAR* DeprecatedFieldName, TArray<TEnum>& OutArray)
{
    if (TryGetEnumArrayField<TEnum>(Object, FieldName, /*out*/ OutArray))
    {
        return true;
    }
    else if (TryGetEnumArrayField<TEnum>(Object, DeprecatedFieldName, /*out*/ OutArray))
    {
        //@TODO: Warn about deprecated field fallback?
        return true;
    }
    else
    {
        return false;
    }
}
 
// A private interface as to not expose RapidJson types
 
TOptional<FText> Read(Json::FConstObject Object, FPluginManifest& Out);
TOptional<FText> Read(Json::FConstObject Object, FPluginDescriptor& Out);
TOptional<FText> Read(Json::FConstObject Object, FModuleDescriptor& Out);
TOptional<FText> Read(Json::FConstObject Object, FLocalizationTargetDescriptor& Out);
TOptional<FText> Read(Json::FConstObject Object, FPluginReferenceDescriptor& Out);
TOptional<FText> Read(Json::FConstObject Object, FPluginDisallowedDescriptor& Out);
 
FCustomBuildSteps ReadCustomBuildSteps(Json::FConstObject Object, const TCHAR* FieldName);
 
// Helper functions to convert and call the rapidjson functions from default json sources
template<typename FUNCTOR>
bool ReadFromDefaultJsonHelper(const FJsonObject& Object, FUNCTOR && Functor)
{
    TOptional<Json::FDocument> Document = Json::ConvertSharedJsonToRapidJsonDocument(Object);
    if (!Document.IsSet())
    {
        return false;
    }
 
    TOptional<Json::FConstObject> RootObject = Json::GetRootObject(*Document);
    if (!RootObject.IsSet())
    {
        return false;
    }
 
    return Functor(*RootObject);
}
 
template<typename TYPE>
bool ReadFromDefaultJson(const FJsonObject& Object, TYPE& Out, FText* OutFailReason)
{
    return ReadFromDefaultJsonHelper(
        Object,
        [&Out, OutFailReason](Json::FConstObject RootObject)
        {
            TOptional<FText> ResultError = Read(RootObject, Out);
            if (ResultError)
            {
                if (OutFailReason)
                {
                    *OutFailReason = *ResultError;
                }
 
                return false;
            }
 
            return true;
        }
    );
}   
 
template<typename TYPE>
TOptional<FText> ReadArray(Json::FConstObject Object, const TCHAR* FieldName, TArray<TYPE>& OutArray)
{
    TOptional<Json::FConstArray> ArrayValue = Json::GetArrayField(Object, FieldName);
    if(ArrayValue.IsSet())
    {
        OutArray.Reserve(ArrayValue->Size());
 
        for (const Json::FValue& ArrayItem : *ArrayValue)
        {
            if (ArrayItem.IsObject())
            {
                TOptional<FText> EntryResult = Read(ArrayItem.GetObject(), OutArray.Emplace_GetRef());
                if (EntryResult.IsSet())
                {
                    OutArray.Pop();
                    return GetArrayObjectChildParseError(FieldName, OutArray.Num(), *EntryResult);
                }
            }
            else
            {
                return GetArrayObjectTypeError(FieldName, OutArray.Num());
            }
        }
    }
    
    return {};
}
 
template<typename TYPE>
bool ReadArrayFromDefaultJson(const FJsonObject& Object, const TCHAR* Name, TArray<TYPE>& OutArray, FText* OutFailReason)
{
    return ReadFromDefaultJsonHelper(
        Object,
        [Name, &OutArray, OutFailReason](Json::FConstObject RootObject)
        {
            TOptional<FText> ArrayError = ReadArray<TYPE>(RootObject, Name, OutArray);
            if (ArrayError)
            {
                if (OutFailReason)
                {
                    *OutFailReason = MoveTemp(*ArrayError);
                }
 
                return false;
            }
 
            return true;
        }
    );
}   
    
}
}  
}