cocos_creator_proj_base/loader/loading_queue.ts

import { handler, gen_handler } from "../util";
import { loader_mgr } from "./loader_mgr";

export class LoadingQueue
{
    private static _inst:LoadingQueue;
    private _loadingMap:Map<string, handler[]>;
    private constructor()
    {
        this._loadingMap = new Map();
    }

    static getInst()
    {
        if(!this._inst) {
            this._inst = new LoadingQueue();
        }
        return this._inst;
    }

    loadPrefabObj(path:string, cb:handler)
    {
        let cbs = this._loadingMap.get(path);
        if(!cbs) {
            cbs = [];
            this._loadingMap.set(path, cbs);
        }
        cbs.push(cb);
        if(cbs.length > 1) {
            return;
        }
        loader_mgr.get_inst().loadPrefabObj(path, gen_handler((node:cc.Node) => {
            const cbs = this._loadingMap.get(path);
            if(cbs) {
                cbs.forEach(cb => cb.exec(node));
                cbs.length = 0;
                this._loadingMap.delete(path);
            }
        }));
    }

    clear()
    {
        this._loadingMap.clear();
    }
}