FlaxEngine/Source/Engine/Content/JsonAsset.h

// Copyright (c) 2012-2023 Wojciech Figat. All rights reserved.

#pragma once

#include "Asset.h"
#include "Engine/Core/ISerializable.h"
#include "Engine/Serialization/Json.h"

/// <summary>
/// Base class for all Json-format assets.
/// </summary>
/// <seealso cref="Asset" />
API_CLASS(Abstract, NoSpawn) class FLAXENGINE_API JsonAssetBase : public Asset
{
    DECLARE_SCRIPTING_TYPE_NO_SPAWN(JsonAssetBase);
protected:
    String _path;
    bool _isVirtualDocument = false;

protected:
    /// <summary>
    /// Initializes a new instance of the <see cref="JsonAssetBase"/> class.
    /// </summary>
    /// <param name="params">The object initialization parameters.</param>
    /// <param name="info">The asset object information.</param>
    explicit JsonAssetBase(const SpawnParams& params, const AssetInfo* info);

public:
    /// <summary>
    /// The parsed json document.
    /// </summary>
    ISerializable::SerializeDocument Document;

    /// <summary>
    /// The data node (reference from Document or Document itself).
    /// </summary>
    ISerializable::DeserializeStream* Data;

    /// <summary>
    /// The data type name from the header. Allows to recognize the data type.
    /// </summary>
    API_FIELD(ReadOnly) String DataTypeName;

    /// <summary>
    /// The serialized data engine build number. Can be used to convert/upgrade data between different formats across different engine versions.
    /// </summary>
    API_FIELD(ReadOnly) int32 DataEngineBuild;

    /// <summary>
    /// The Json data (as string).
    /// </summary>
    API_PROPERTY() String GetData() const;

    /// <summary>
    /// The Json data (as string).
    /// </summary>
    API_PROPERTY() void SetData(const StringView& value);

    /// <summary>
    /// Initializes the virtual Json asset with custom data.
    /// </summary>
    /// <remarks>Can be used only for virtual assets created at runtime.</remarks>
    /// <param name="dataTypeName">The data type name from the header. Allows to recognize the data type.</param>
    /// <param name="dataJson">The Json with serialized data.</param>
    /// <returns>True if failed, otherwise false.</returns>
    API_FUNCTION() bool Init(const StringView& dataTypeName, const StringAnsiView& dataJson);

#if USE_EDITOR
    /// <summary>
    /// Parses Json string to find any object references inside it. It can produce list of references to assets and/or scene objects. Supported only in Editor.
    /// </summary>
    /// <param name="json">The Json string.</param>
    /// <param name="output">The output list of object IDs references by the asset (appended, not cleared).</param>
    API_FUNCTION() static void GetReferences(const StringAnsiView& json, API_PARAM(Out) Array<Guid, HeapAllocation>& output);

    /// <summary>
    /// Saves this asset to the file. Supported only in Editor.
    /// </summary>
    /// <param name="path">The custom asset path to use for the saving. Use empty value to save this asset to its own storage location. Can be used to duplicate asset. Must be specified when saving virtual asset.</param>
    /// <returns>True if cannot save data, otherwise false.</returns>
    API_FUNCTION() bool Save(const StringView& path = StringView::Empty) const;

    /// <summary>
    /// Saves this asset to the Json Writer buffer (both ID, Typename header and Data contents). Supported only in Editor.
    /// </summary>
    /// <param name="writer">The output Json Writer to write asset.</param>
    /// <returns>True if cannot save data, otherwise false.</returns>
    bool Save(JsonWriter& writer) const;
#endif

protected:
    // Gets the serialized Json data (from runtime state).
    virtual void OnGetData(rapidjson_flax::StringBuffer& buffer) const;

public:
    // [Asset]
    const String& GetPath() const override;
    uint64 GetMemoryUsage() const override;
#if USE_EDITOR
    void GetReferences(Array<Guid, HeapAllocation>& output) const override;
#endif

protected:
    // [Asset]
    LoadResult loadAsset() override;
    void unload(bool isReloading) override;
#if USE_EDITOR
    void onRename(const StringView& newPath) override;
#endif
};

/// <summary>
/// Generic type of Json-format asset. It provides the managed representation of this resource data so it can be accessed via C# API.
/// </summary>
/// <seealso cref="JsonAssetBase" />
API_CLASS(NoSpawn) class FLAXENGINE_API JsonAsset : public JsonAssetBase
{
    DECLARE_ASSET_HEADER(JsonAsset);
private:
    ScriptingType::Dtor _dtor;
    bool _isAfterReload = false;

public:
    /// <summary>
    /// The scripting type of the deserialized unmanaged object instance (e.g. PhysicalMaterial).
    /// </summary>
    ScriptingTypeHandle InstanceType;

    /// <summary>
    /// The deserialized unmanaged object instance (e.g. PhysicalMaterial). Might be null if asset was loaded before binary module with that asset was loaded (use GetInstance for this case).
    /// </summary>
    void* Instance;

    /// <summary>
    /// Gets the deserialized native object instance of the given type. Returns null if asset is not loaded or loaded object has different type.
    /// </summary>
    /// <returns>The asset instance object or null.</returns>
    template<typename T>
    T* GetInstance() const
    {
        const_cast<JsonAsset*>(this)->CreateInstance();
        return Instance && InstanceType.IsAssignableFrom(T::TypeInitializer) ? (T*)Instance : nullptr;
    }

public:
    // [JsonAssetBase]
    uint64 GetMemoryUsage() const override;

protected:
    // [JsonAssetBase]
    LoadResult loadAsset() override;
    void unload(bool isReloading) override;
    void onLoaded_MainThread() override;

private:
    bool CreateInstance();
    void DeleteInstance();
#if USE_EDITOR
    void OnScriptsReloadStart();
    void OnScriptsReloaded();
#endif
};