90 lines
2.6 KiB
JavaScript
90 lines
2.6 KiB
JavaScript
/*
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Copyright 2020 The Matrix.org Foundation C.I.C.
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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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http://www.apache.org/licenses/LICENSE-2.0
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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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import {BaseObservableValue} from "../../observable/ObservableValue.js";
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export class ObservedEventMap {
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constructor(notifyEmpty) {
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this._map = new Map();
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this._notifyEmpty = notifyEmpty;
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}
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observe(eventId, eventEntry = null) {
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let observable = this._map.get(eventId);
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if (!observable) {
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observable = new ObservedEvent(this, eventEntry);
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this._map.set(eventId, observable);
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}
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return observable;
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}
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updateEvents(eventEntries) {
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for (let i = 0; i < eventEntries.length; i += 1) {
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const entry = eventEntries[i];
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const observable = this._map.get(entry.id);
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observable?.update(entry);
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}
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}
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_remove(observable) {
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this._map.delete(observable.get().id);
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if (this._map.size === 0) {
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this._notifyEmpty();
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}
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}
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}
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class ObservedEvent extends BaseObservableValue {
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constructor(eventMap, entry) {
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super();
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this._eventMap = eventMap;
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this._entry = entry;
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// remove subscription in microtask after creating it
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// otherwise ObservedEvents would easily never get
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// removed if you never subscribe
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Promise.resolve().then(() => {
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if (!this.hasSubscriptions) {
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this._eventMap.remove(this);
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this._eventMap = null;
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}
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});
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}
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subscribe(handler) {
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if (!this._eventMap) {
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throw new Error("ObservedEvent expired, subscribe right after calling room.observeEvent()");
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}
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return super.subscribe(handler);
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}
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onUnsubscribeLast() {
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this._eventMap._remove(this);
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this._eventMap = null;
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super.onUnsubscribeLast();
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}
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update(entry) {
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// entries are mostly updated in-place,
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// apart from when they are created,
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// but doesn't hurt to reassign
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this._entry = entry;
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this.emit(this._entry);
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}
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get() {
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return this._entry;
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}
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}
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