1// Copyright (C) 2018 The Android Open Source Project 2// 3// Licensed under the Apache License, Version 2.0 (the "License"); 4// you may not use this file except in compliance with the License. 5// You may obtain a copy of the License at 6// 7// http://www.apache.org/licenses/LICENSE-2.0 8// 9// Unless required by applicable law or agreed to in writing, software 10// distributed under the License is distributed on an "AS IS" BASIS, 11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12// See the License for the specific language governing permissions and 13// limitations under the License. 14 15import {Disposable} from '../base/disposable'; 16 17export interface HasKind { 18 kind: string; 19} 20 21export class RegistryError extends Error { 22 constructor(message?: string) { 23 super(message); 24 this.name = this.constructor.name; 25 } 26} 27 28export class Registry<T> { 29 private key: (t: T) => string; 30 protected registry: Map<string, T>; 31 32 static kindRegistry<T extends HasKind>(): Registry<T> { 33 return new Registry<T>((t) => t.kind); 34 } 35 36 constructor(key: (t: T) => string) { 37 this.registry = new Map<string, T>(); 38 this.key = key; 39 } 40 41 register(registrant: T): Disposable { 42 const kind = this.key(registrant); 43 if (this.registry.has(kind)) { 44 throw new RegistryError( 45 `Registrant ${kind} already exists in the registry`, 46 ); 47 } 48 this.registry.set(kind, registrant); 49 50 return { 51 dispose: () => this.registry.delete(kind), 52 }; 53 } 54 55 has(kind: string): boolean { 56 return this.registry.has(kind); 57 } 58 59 get(kind: string): T { 60 const registrant = this.registry.get(kind); 61 if (registrant === undefined) { 62 throw new RegistryError(`${kind} has not been registered.`); 63 } 64 return registrant; 65 } 66 67 tryGet(kind: string): T | undefined { 68 return this.registry.get(kind); 69 } 70 71 // Support iteration: for (const foo of fooRegistry.values()) { ... } 72 *values() { 73 yield* this.registry.values(); 74 } 75 76 unregisterAllForTesting(): void { 77 this.registry.clear(); 78 } 79} 80