56 lines
1.8 KiB
TypeScript
56 lines
1.8 KiB
TypeScript
/*
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Copyright 2022 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 type {StateObserver} from "./types";
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import type {StateEvent} from "../../storage/types";
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import type {Transaction} from "../../storage/idb/Transaction";
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import {BaseObservableValue} from "../../../observable/value/BaseObservableValue";
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/**
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* Observable value for a state event with a given type and state key.
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* Unsubscribes when last subscription is removed */
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export class ObservedStateKeyValue extends BaseObservableValue<StateEvent | undefined> implements StateObserver {
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private event?: StateEvent;
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private removeCallback?: () => void;
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constructor(private readonly type: string, private readonly stateKey: string) {
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super();
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}
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/** @internal */
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async load(roomId: string, txn: Transaction): Promise<void> {
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this.event = (await txn.roomState.get(roomId, this.type, this.stateKey))?.event;
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}
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/** @internal */
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handleStateEvent(event: StateEvent) {
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if (event.type === this.type && event.state_key === this.stateKey) {
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this.event = event;
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this.emit(this.get());
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}
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}
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get(): StateEvent | undefined {
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return this.event;
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}
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setRemoveCallback(callback: () => void) {
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this.removeCallback = callback;
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}
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onUnsubscribeLast() {
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this.removeCallback?.();
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}
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}
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