cocos_lib/cocos/core/assets/Asset.h

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#pragma once

#include <functional>
#include "base/std/any.h"
#include "base/std/optional.h"

#include "base/Macros.h"
#include "core/Types.h"
#include "core/data/Object.h"
#include "core/event/EventTarget.h"

namespace cc {

class Node;

class Asset : public CCObject {
public:
    using Super = CCObject;

    Asset();
    ~Asset() override;

    /**
     * @en
     * Returns the url of this asset's native object, if none it will returns an empty string.
     * @zh
     * 返回该资源对应的目标平台资源的 URL，如果没有将返回一个空字符串。
     * @readOnly
     */
    ccstd::string getNativeUrl() const;

    NativeDep getNativeDep() const;

    inline const ccstd::string &getUuid() const { return _uuid; }
    inline void setUuid(const ccstd::string &uuid) { _uuid = uuid; }

    /**
     * @en
     * The underlying native asset of this asset if one is available.<br>
     * This property can be used to access additional details or functionality related to the asset.<br>
     * This property will be initialized by the loader if `_native` is available.
     * @zh
     * 此资源的基础资源（如果有）。 此属性可用于访问与资源相关的其他详细信息或功能。<br>
     * 如果`_native`可用，则此属性将由加载器初始化。
     * @default null
     * @private
     */
    virtual ccstd::any getNativeAsset() const {
        return _file;
    }

    virtual void setNativeAsset(const ccstd::any &obj) {
        _file = obj;
    }

    /**
     * @param error - null or the error info
     * @param node - the created node or null
     */
    using CreateNodeCallback = std::function<void(Error, Node *)>;
    /**
     * @en
     * Create a new node using this asset in the scene.<br/>
     * If this type of asset don't have its corresponding node type, this method should be null.
     * @zh
     * 使用该资源在场景中创建一个新节点。<br/>
     * 如果这类资源没有相应的节点类型，该方法应该是空的。
     */
    virtual void createNode(const CreateNodeCallback &cb) {}

    void addAssetRef();
    void decAssetRef(bool autoRelease = true);
    inline uint32_t getAssetRefCount() const { return _assetRefCount; }

    virtual void onLoaded() {}

    virtual void initDefault() { initDefault(ccstd::nullopt); }

    virtual void initDefault(const ccstd::optional<ccstd::string> &uuid);

    virtual bool validate() const { return true; }

    bool isDefault() const { return _isDefault; }

    bool destroy() override;

    void destruct() override;

    // SERIALIZATION

    /**
     * @return
     */
    virtual ccstd::any serialize(const ccstd::any & /*ctxForExporting*/) { return ccstd::any{}; };

    /**
     *
     * @param data
     */
    virtual void deserialize(const ccstd::any &serializedData, const ccstd::any &handle) {}

    ccstd::string toString() const override { return _nativeUrl; }

protected:
    /**
     * @en
     * Set native file name for this asset.
     * @zh
     * 为此资源设置原始文件名。
     * @seealso nativeUrl
     *
     * @param filename
     * @param inLibrary
     * @private
     */
    void setRawAsset(const ccstd::string &filename, bool inLibrary = true);

    // Make _native, _nativeUrl public for deserialization
public:
    ccstd::string _native;
    ccstd::string _nativeUrl;

protected:
    ccstd::string _uuid;

    ccstd::any _file;
    uint32_t _assetRefCount{0};

    bool _loaded{true};
    bool _isDefault{false};

    CC_DISALLOW_COPY_MOVE_ASSIGN(Asset);
};

} // namespace cc