import mongoose from "mongoose";
export declare const syncSchema: {
    userId: {
        type: mongoose.Types.ObjectIdConstructor;
        required: boolean;
    };
    oid: {
        type: mongoose.Types.ObjectIdConstructor;
        required: boolean;
    };
    version: NumberConstructor;
};
export interface SyncDoc {
    userId: mongoose.Types.ObjectId;
    oid: mongoose.Types.ObjectId;
    version: number;
}
export interface SyncModel<T> {
    createNew(userId: string, oid: string, extra: Object): Promise<T>;
    checkVersion(userId: string, oid: string, version: number): Promise<boolean>;
    increaseVersion(userId: mongoose.Types.ObjectId, oid: mongoose.Types.ObjectId): Promise<void>;
}
export declare const extendSchemaWithSync: (schema: mongoose.Schema, model: () => mongoose.Model<mongoose.Document<any>>) => void;