1/* 2 * Copyright (C) 2022 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17/** 18 * Type of the onProgressUpdate callback function. 19 */ 20export type OnProgressUpdateType = (percentage: number) => void; 21 22/** 23 * Utility functions for working with functions. 24 */ 25export class FunctionUtils { 26 /** 27 * A function that does nothing. 28 */ 29 static readonly DO_NOTHING = () => { 30 // do nothing 31 }; 32 33 /** 34 * A function that does nothing asynchronously. 35 */ 36 static readonly DO_NOTHING_ASYNC = (): Promise<void> => { 37 return Promise.resolve(); 38 }; 39 40 /** 41 * Mixin two objects together. 42 * 43 * This function takes two objects and returns a new object that is the 44 * result of merging the two objects. The properties of the first object 45 * take precedence over the properties of the second object if there are 46 * any conflicts. 47 * 48 * @param a The first object. 49 * @param b The second object. 50 * @return The merged object. 51 */ 52 static mixin<T extends object, U extends object>(a: T, b: U): T & U { 53 const ret = {}; 54 Object.assign(ret, a); 55 Object.assign(ret, b); 56 57 const assignMethods = (dst: object, src: object) => { 58 for (const methodName of Object.getOwnPropertyNames( 59 Object.getPrototypeOf(src), 60 )) { 61 const method = (src as any)[methodName]; 62 (dst as any)[methodName] = method; 63 } 64 }; 65 66 assignMethods(ret, a); 67 assignMethods(ret, b); 68 69 return ret as T & U; 70 } 71} 72