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// ES6 Set does not allow to reasonably store compound objects; this class 18// rectifies the problem by implementing generic set on top of Map and an 19// injective function from objects of generic type to strings. 20export class GenericSet<T> { 21 interner: (t: T) => string; 22 23 // Passed function should be injective (as in never having the same output for 24 // two different inputs). 25 constructor(interner: (t: T) => string) { 26 this.interner = interner; 27 } 28 29 backingMap = new Map<string, T>(); 30 31 has(column: T): boolean { 32 return this.backingMap.has(this.interner(column)); 33 } 34 35 add(column: T) { 36 this.backingMap.set(this.interner(column), column); 37 } 38 39 delete(column: T) { 40 this.backingMap.delete(this.interner(column)); 41 } 42 43 values(): Iterable<T> { 44 return this.backingMap.values(); 45 } 46} 47