78 lines
2.4 KiB
JavaScript
78 lines
2.4 KiB
JavaScript
/*
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Copyright 2017 New Vector Ltd
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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 RoomViewStore from './stores/RoomViewStore';
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/**
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* Consumes changes from the RoomViewStore and notifies specific things
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* about when the active room changes. Unlike listening for RoomViewStore
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* changes, you can subscribe to only changes relevant to a particular
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* room.
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*
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* TODO: If we introduce an observer for something else, factor out
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* the adding / removing of listeners & emitting into a common class.
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*/
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class ActiveRoomObserver {
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constructor() {
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this._listeners = {};
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this._activeRoomId = RoomViewStore.getRoomId();
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// TODO: We could self-destruct when the last listener goes away, or at least
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// stop listening.
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this._roomStoreToken = RoomViewStore.addListener(this._onRoomViewStoreUpdate.bind(this));
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}
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addListener(roomId, listener) {
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if (!this._listeners[roomId]) this._listeners[roomId] = [];
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this._listeners[roomId].push(listener);
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}
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removeListener(roomId, listener) {
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if (this._listeners[roomId]) {
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const i = this._listeners[roomId].indexOf(listener);
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if (i > -1) {
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this._listeners[roomId].splice(i, 1);
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}
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} else {
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console.warn("Unregistering unrecognised listener (roomId=" + roomId + ")");
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}
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}
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_emit(roomId) {
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if (!this._listeners[roomId]) return;
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for (const l of this._listeners[roomId]) {
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l.call();
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}
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}
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_onRoomViewStoreUpdate() {
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// emit for the old room ID
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if (this._activeRoomId) this._emit(this._activeRoomId);
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// update our cache
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this._activeRoomId = RoomViewStore.getRoomId();
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// and emit for the new one
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if (this._activeRoomId) this._emit(this._activeRoomId);
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}
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}
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if (global.mx_ActiveRoomObserver === undefined) {
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global.mx_ActiveRoomObserver = new ActiveRoomObserver();
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}
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export default global.mx_ActiveRoomObserver;
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