cocos_creator_framework/assets/Script/res/ResLoader.ts

/**
 * ResLoader2，封装资源的加载和卸载接口，隐藏新老资源底层差异
 * 1. 加载资源接口
 * 2. 卸载资源接口
 * 
 * 2021-1-24 by 宝爷
 */

import { Asset, js, error, Constructor, resources, __private, assetManager, AssetManager } from "cc";
export type ProgressCallback = __private.cocos_core_asset_manager_shared_ProgressCallback;
export type CompleteCallback<T = any> = __private.cocos_core_asset_manager_shared_CompleteCallbackWithData;
export type IRemoteOptions = __private.cocos_core_asset_manager_shared_IRemoteOptions;
export type AssetType<T = Asset> = Constructor<T>;

interface ILoadResArgs<T extends Asset> {
    bundle?: string;
    dir?: string;
    paths: string | string[];
    type: AssetType<T> | null;
    onProgress: ProgressCallback | null;
    onComplete: CompleteCallback<T> | null;
}

export default class ResLoader {

    public parseLoadResArgs<T extends Asset>(
        paths: string | string[],
        type?: AssetType<T> | ProgressCallback | CompleteCallback | null,
        onProgress?: AssetType<T> | ProgressCallback | CompleteCallback | null,
        onComplete?: ProgressCallback | CompleteCallback | null
    ) {
        let pathsOut: any = paths;
        let typeOut: any = type;
        let onProgressOut: any = onProgress;
        let onCompleteOut: any = onComplete;
        if (onComplete === undefined) {
            const isValidType = js.isChildClassOf(type as AssetType, Asset);
            if (onProgress) {
                onCompleteOut = onProgress as CompleteCallback;
                if (isValidType) {
                    onProgressOut = null;
                }
            } else if (onProgress === undefined && !isValidType) {
                onCompleteOut = type as CompleteCallback;
                onProgressOut = null;
                typeOut = null;
            }
            if (onProgress !== undefined && !isValidType) {
                onProgressOut = type as ProgressCallback;
                typeOut = null;
            }
        }
        return { paths: pathsOut, type: typeOut, onProgress: onProgressOut, onComplete: onCompleteOut };
    }

    private loadByBundleAndArgs<T extends Asset>(bundle: AssetManager.Bundle, args: ILoadResArgs<T>): void {
        if (args.dir) {
            bundle.loadDir(args.paths as string, args.type, args.onProgress, args.onComplete);
        } else {
            if (typeof args.paths == 'string') {
                bundle.load(args.paths, args.type, args.onProgress, args.onComplete);
            } else {
                bundle.load(args.paths, args.type, args.onProgress, args.onComplete);
            }    
        }
    }

    private loadByArgs<T extends Asset>(args: ILoadResArgs<T>) {
        if (args.bundle) {
            if (assetManager.bundles.has(args.bundle)) {
                let bundle = assetManager.bundles.get(args.bundle);
                this.loadByBundleAndArgs(bundle!, args);
            } else {
                // 自动加载bundle
                assetManager.loadBundle(args.bundle, (err, bundle) => {
                    if (!err) {
                        this.loadByBundleAndArgs(bundle, args);
                    }
                })
            }
        } else {
            this.loadByBundleAndArgs(resources, args);
        }
    }

    public load<T extends Asset>(bundleName: string, paths: string | string[], type: AssetType<T> | null, onProgress: ProgressCallback | null, onComplete: CompleteCallback<T> | null): void;
    public load<T extends Asset>(bundleName: string, paths: string | string[], onProgress: ProgressCallback | null, onComplete: CompleteCallback<T> | null): void;
    public load<T extends Asset>(bundleName: string, paths: string | string[], onComplete?: CompleteCallback<T> | null): void;
    public load<T extends Asset>(bundleName: string, paths: string | string[], type: AssetType<T> | null, onComplete?: CompleteCallback<T> | null): void;
    public load<T extends Asset>(paths: string | string[], type: AssetType<T> | null, onProgress: ProgressCallback | null, onComplete: CompleteCallback<T> | null): void;
    public load<T extends Asset>(paths: string | string[], onProgress: ProgressCallback | null, onComplete: CompleteCallback<T> | null): void;
    public load<T extends Asset>(paths: string | string[], onComplete?: CompleteCallback<T> | null): void;
    public load<T extends Asset>(paths: string | string[], type: AssetType<T> | null, onComplete?: CompleteCallback<T> | null): void;
    public load<T extends Asset>(
        bundleName: string,
        paths?: string | string[] | AssetType<T> | ProgressCallback | CompleteCallback | null,
        type?: AssetType<T> | ProgressCallback | CompleteCallback | null,
        onProgress?: ProgressCallback | CompleteCallback | null,
        onComplete?: CompleteCallback | null,
    ) {
        let args: ILoadResArgs<T> | null = null;
        if (typeof paths === "string" || paths instanceof Array) {
            args = this.parseLoadResArgs(paths, type, onProgress, onComplete);
            args.bundle = bundleName;
        } else {
            args = this.parseLoadResArgs(bundleName, paths, type, onProgress);
        }
        this.loadByArgs(args);
    }

    public loadDir<T extends Asset>(bundleName: string, dir: string, type: AssetType<T> | null, onProgress: ProgressCallback | null, onComplete: CompleteCallback<T[]> | null): void;
    public loadDir<T extends Asset>(bundleName: string, dir: string, onProgress: ProgressCallback | null, onComplete: CompleteCallback<T[]> | null): void;
    public loadDir<T extends Asset>(bundleName: string, dir: string, onComplete?: CompleteCallback<T[]> | null): void;
    public loadDir<T extends Asset>(bundleName: string, dir: string, type: AssetType<T> | null, onComplete?: CompleteCallback<T[]> | null): void;
    public loadDir<T extends Asset>(dir: string, type: AssetType<T> | null, onProgress: ProgressCallback | null, onComplete: CompleteCallback<T[]> | null): void;
    public loadDir<T extends Asset>(dir: string, onProgress: ProgressCallback | null, onComplete: CompleteCallback<T[]> | null): void;
    public loadDir<T extends Asset>(dir: string, onComplete?: CompleteCallback<T[]> | null): void;
    public loadDir<T extends Asset>(dir: string, type: AssetType<T> | null, onComplete?: CompleteCallback<T[]> | null): void;
    public loadDir<T extends Asset>(
        bundleName: string,
        dir?: string | AssetType<T> | ProgressCallback | CompleteCallback | null,
        type?: AssetType<T> | ProgressCallback | CompleteCallback | null,
        onProgress?: ProgressCallback | CompleteCallback | null,
        onComplete?: CompleteCallback | null,
    ) {
        let args: ILoadResArgs<T> | null = null;
        if (typeof dir === "string") {
            args = this.parseLoadResArgs(dir, type, onProgress, onComplete);
            args.bundle = bundleName;
        } else {
            args = this.parseLoadResArgs(bundleName, dir, type, onProgress);
        }
        args.dir = args.paths as string;
        this.loadByArgs(args);
    }

    public loadRemote<T extends Asset>(url: string, options: IRemoteOptions | null, onComplete?: CompleteCallback<T> | null): void;
    public loadRemote<T extends Asset>(url: string, onComplete?: CompleteCallback<T> | null): void;
    public loadRemote(url: string, ...args: any): void {
        assetManager.loadRemote(url, args);
    }
}

export let resLoader = new ResLoader();