FlaxEngine/Source/Engine/Content/JsonAsset.cpp

// Copyright (c) 2012-2021 Wojciech Figat. All rights reserved.

#include "JsonAsset.h"
#include "Engine/Threading/Threading.h"
#if USE_EDITOR
#include "Engine/Platform/File.h"
#include "Engine/Core/Types/DataContainer.h"
#else
#include "Storage/ContentStorageManager.h"
#endif
#include "Content.h"
#include "FlaxEngine.Gen.h"
#include "Cache/AssetsCache.h"
#include "Engine/Core/Log.h"
#include "Engine/Serialization/JsonTools.h"
#include "Engine/Content/Factories/JsonAssetFactory.h"
#include "Engine/Core/Cache.h"
#include "Engine/Debug/Exceptions/JsonParseException.h"
#include "Engine/Scripting/Scripting.h"
#include "Engine/Utilities/StringConverter.h"

JsonAssetBase::JsonAssetBase(const SpawnParams& params, const AssetInfo* info)
    : Asset(params, info)
    , _path(info->Path)
    , Data(nullptr)
    , DataEngineBuild(0)
{
}

String JsonAssetBase::GetData() const
{
    if (Data == nullptr)
        return String::Empty;

    // Get serialized data
    rapidjson_flax::StringBuffer buffer;
    rapidjson_flax::Writer<rapidjson_flax::StringBuffer> writer(buffer);
    Data->Accept(writer);

    return String((const char*)buffer.GetString(), (int32)buffer.GetSize());
}

const String& JsonAssetBase::GetPath() const
{
#if USE_EDITOR
    return _path;
#else
    // In build all assets are packed into packages so use ID for original path lookup
    return Content::GetRegistry()->GetAssetPath(_id);
#endif
}

#if USE_EDITOR

void FindIds(ISerializable::DeserializeStream& node, Array<Guid>& output)
{
    if (node.IsObject())
    {
        for (auto i = node.MemberBegin(); i != node.MemberEnd(); ++i)
        {
            FindIds(i->value, output);
        }
    }
    else if (node.IsArray())
    {
        for (rapidjson::SizeType i = 0; i < node.Size(); i++)
        {
            FindIds(node[i], output);
        }
    }
    else if (node.IsString())
    {
        const auto length = node.GetStringLength();
        if (length == 32)
        {
            // Try parse as Guid in format `N` (32 hex chars)
            Guid id;
            if (!Guid::Parse(node.GetText(), id))
                output.Add(id);
        }
    }
}

void JsonAssetBase::GetReferences(Array<Guid>& output) const
{
    if (Data == nullptr)
        return;

    // Unified way to find asset references inside a generic asset.
    // This could deserialize managed/unmanaged object or load actors in case of SceneAsset or PrefabAsset.
    // But this would be performance killer.
    // The fastest way is to just iterate through the json and find all the Guid values.
    // It produces many invalid ids (like refs to scene objects).
    // But it's super fast, super low-memory and doesn't involve any advanced systems integration.

    FindIds(*Data, output);
}

#endif

Asset::LoadResult JsonAssetBase::loadAsset()
{
    // Load data (raw json file in editor, cooked asset in build game)
#if USE_EDITOR
    BytesContainer data;
    if (File::ReadAllBytes(GetPath(), data))
    {
        LOG(Warning, "Filed to load json asset data. {0}", ToString());
        return LoadResult::CannotLoadData;
    }
    if (data.Length() == 0)
    {
        return LoadResult::MissingDataChunk;
    }
#else
    // Get the asset storage container but don't load it now
    const auto storage = ContentStorageManager::GetStorage(GetPath(), true);
    if (!storage)
        return LoadResult::CannotLoadStorage;

    // Load header
    AssetInitData initData;
    if (storage->LoadAssetHeader(GetID(), initData))
        return LoadResult::CannotLoadInitData;

    // Load the actual data
    auto chunk = initData.Header.Chunks[0];
    if (chunk == nullptr)
        return LoadResult::MissingDataChunk;
    if (storage->LoadAssetChunk(chunk))
        return LoadResult::CannotLoadData;
    auto& data = chunk->Data;
#endif

    // Parse json document
    Document.Parse(data.Get<char>(), data.Length());
    if (Document.HasParseError())
    {
        Log::JsonParseException(Document.GetParseError(), Document.GetErrorOffset());
        return LoadResult::CannotLoadData;
    }

    // Gather information from the header
    const auto id = JsonTools::GetGuid(Document, "ID");
    if (id != _id)
    {
        LOG(Warning, "Invalid json asset id. Asset: {0}, serialized: {1}.", _id, id);
        return LoadResult::InvalidData;
    }
    DataTypeName = JsonTools::GetString(Document, "TypeName");
    DataEngineBuild = JsonTools::GetInt(Document, "EngineBuild", FLAXENGINE_VERSION_BUILD);
    auto dataMember = Document.FindMember("Data");
    if (dataMember == Document.MemberEnd())
    {
        LOG(Warning, "Missing json asset data.");
        return LoadResult::InvalidData;
    }
    Data = &dataMember->value;

    return LoadResult::Ok;
}

void JsonAssetBase::unload(bool isReloading)
{
    ISerializable::SerializeDocument tmp;
    Document.Swap(tmp);
    Data = nullptr;
    DataTypeName.Clear();
    DataEngineBuild = 0;
}

#if USE_EDITOR

void JsonAssetBase::onRename(const StringView& newPath)
{
    ScopeLock lock(Locker);

    // Rename
    _path = newPath;
}

#endif

REGISTER_JSON_ASSET(JsonAsset, "FlaxEngine.JsonAsset", true);

JsonAsset::JsonAsset(const SpawnParams& params, const AssetInfo* info)
    : JsonAssetBase(params, info)
    , Instance(nullptr)
{
}

Asset::LoadResult JsonAsset::loadAsset()
{
    // Base
    auto result = JsonAssetBase::loadAsset();
    if (result != LoadResult::Ok || IsInternalType())
        return result;

    // Try to scripting type for this data
    const StringAsANSI<> dataTypeNameAnsi(DataTypeName.Get(), DataTypeName.Length());
    const auto typeHandle = Scripting::FindScriptingType(StringAnsiView(dataTypeNameAnsi.Get(), DataTypeName.Length()));
    if (typeHandle)
    {
        auto& type = typeHandle.GetType();
        switch (type.Type)
        {
        case ScriptingTypes::Class:
        {
            // Ensure that object can deserialized
            const ScriptingType::InterfaceImplementation* interfaces = type.GetInterface(&ISerializable::TypeInitializer);
            if (!interfaces)
            {
                LOG(Warning, "Cannot deserialize {0} from Json Asset because it doesn't implement ISerializable interface.", type.ToString());
                break;
            }

            // Allocate object
            const auto instance = Allocator::Allocate(type.Size);
            if (!instance)
                return LoadResult::Failed;
            Instance = instance;
            InstanceType = typeHandle;
            _dtor = type.Class.Dtor;
            type.Class.Ctor(instance);

            // Deserialize object
            auto modifier = Cache::ISerializeModifier.Get();
            modifier->EngineBuild = DataEngineBuild;
            ((ISerializable*)((byte*)instance + interfaces->VTableOffset))->Deserialize(*Data, modifier.Value);
            // TODO: delete object when containing BinaryModule gets unloaded
            break;
        }
        default: ;
        }
    }

    return result;
}

void JsonAsset::unload(bool isReloading)
{
    // Base
    JsonAssetBase::unload(isReloading);

    if (Instance)
    {
        InstanceType = ScriptingTypeHandle();
        _dtor(Instance);
        Allocator::Free(Instance);
        Instance = nullptr;
        _dtor = nullptr;
    }
}