/**
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* @license
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* Copyright 2018 Google LLC. All Rights Reserved.
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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* =============================================================================
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*/
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import {IOHandler} from './types';
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export type IORouter = (url: string|string[], onProgress?: Function) =>
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IOHandler;
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export class IORouterRegistry {
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// Singleton instance.
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private static instance: IORouterRegistry;
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private saveRouters: IORouter[];
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private loadRouters: IORouter[];
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private constructor() {
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this.saveRouters = [];
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this.loadRouters = [];
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}
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private static getInstance(): IORouterRegistry {
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if (IORouterRegistry.instance == null) {
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IORouterRegistry.instance = new IORouterRegistry();
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}
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return IORouterRegistry.instance;
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}
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/**
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* Register a save-handler router.
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*
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* @param saveRouter A function that maps a URL-like string onto an instance
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* of `IOHandler` with the `save` method defined or `null`.
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*/
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static registerSaveRouter(saveRouter: IORouter) {
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IORouterRegistry.getInstance().saveRouters.push(saveRouter);
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}
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/**
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* Register a load-handler router.
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*
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* @param loadRouter A function that maps a URL-like string onto an instance
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* of `IOHandler` with the `load` method defined or `null`.
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*/
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static registerLoadRouter(loadRouter: IORouter) {
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IORouterRegistry.getInstance().loadRouters.push(loadRouter);
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}
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/**
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* Look up IOHandler for saving, given a URL-like string.
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*
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* @param url
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* @returns If only one match is found, an instance of IOHandler with the
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* `save` method defined. If no match is found, `null`.
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* @throws Error, if more than one match is found.
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*/
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static getSaveHandlers(url: string|string[]): IOHandler[] {
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return IORouterRegistry.getHandlers(url, 'save');
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}
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/**
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* Look up IOHandler for loading, given a URL-like string.
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*
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* @param url
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* @param onProgress Optional, progress callback function, fired periodically
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* before the load is completed.
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* @returns All valid handlers for `url`, given the currently registered
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* handler routers.
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*/
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static getLoadHandlers(url: string|string[], onProgress?: Function):
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IOHandler[] {
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return IORouterRegistry.getHandlers(url, 'load', onProgress);
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}
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private static getHandlers(
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url: string|string[], handlerType: 'save'|'load',
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onProgress?: Function): IOHandler[] {
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const validHandlers: IOHandler[] = [];
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const routers = handlerType === 'load' ?
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IORouterRegistry.getInstance().loadRouters :
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IORouterRegistry.getInstance().saveRouters;
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routers.forEach(router => {
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const handler = router(url, onProgress);
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if (handler !== null) {
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validHandlers.push(handler);
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}
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});
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return validHandlers;
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}
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}
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export const registerSaveRouter = (loudRouter: IORouter) =>
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IORouterRegistry.registerSaveRouter(loudRouter);
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export const registerLoadRouter = (loudRouter: IORouter) =>
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IORouterRegistry.registerLoadRouter(loudRouter);
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export const getSaveHandlers = (url: string|string[]) =>
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IORouterRegistry.getSaveHandlers(url);
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export const getLoadHandlers = (url: string|string[], onProgress?: Function) =>
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IORouterRegistry.getLoadHandlers(url, onProgress);
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