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mirror of https://github.com/laurent22/joplin.git synced 2024-12-09 08:45:55 +02:00
joplin/packages/lib/eventManager.ts
Henry Heino c0c3b4d23e
Mobile: Plugins: Fix event listener memory leak when disabling/uninstalling plugins (#10280)
Co-authored-by: Laurent Cozic <laurent22@users.noreply.github.com>
2024-04-11 09:04:47 +01:00

182 lines
6.0 KiB
TypeScript

const fastDeepEqual = require('fast-deep-equal');
import { EventEmitter } from 'events';
import type { State as AppState } from './reducer';
export enum EventName {
ResourceCreate = 'resourceCreate',
ResourceChange = 'resourceChange',
SettingsChange = 'settingsChange',
TodoToggle = 'todoToggle',
NoteTypeToggle = 'noteTypeToggle',
SyncStart = 'syncStart',
SessionEstablished = 'sessionEstablished',
SyncComplete = 'syncComplete',
ItemChange = 'itemChange',
NoteAlarmTrigger = 'noteAlarmTrigger',
AlarmChange = 'alarmChange',
KeymapChange = 'keymapChange',
NoteContentChange = 'noteContentChange',
OcrServiceResourcesProcessed = 'ocrServiceResourcesProcessed',
NoteResourceIndexed = 'noteResourceIndexed',
}
// eslint-disable-next-line @typescript-eslint/no-explicit-any -- Partial refactor of old code from before rule was applied
export type EventListenerCallback = (...args: any[])=> void;
// eslint-disable-next-line @typescript-eslint/no-explicit-any -- Partial refactor of old code from before rule was applied
type AppStateChangeCallback = (event: { value: any })=> void;
// eslint-disable-next-line @typescript-eslint/no-explicit-any -- Partial refactor of old code from before rule was applied
type FilterObject = any;
export type FilterHandler = (object: FilterObject)=> FilterObject;
export class EventManager {
private emitter_: EventEmitter;
private appStatePrevious_: Record<string, AppState[keyof AppState]>;
private appStateWatchedProps_: string[];
private appStateListeners_: Record<string, AppStateChangeCallback[]>;
public constructor() {
this.reset();
}
public reset() {
this.emitter_ = new EventEmitter();
this.appStatePrevious_ = {};
this.appStateWatchedProps_ = [];
this.appStateListeners_ = {};
}
public on(eventName: EventName, callback: EventListenerCallback) {
return this.emitter_.on(eventName, callback);
}
// eslint-disable-next-line @typescript-eslint/no-explicit-any -- Old code before rule was applied
public emit(eventName: EventName, object: any = null) {
return this.emitter_.emit(eventName, object);
}
public removeListener(eventName: string, callback: EventListenerCallback) {
return this.emitter_.removeListener(eventName, callback);
}
public off(eventName: EventName, callback: EventListenerCallback) {
return this.removeListener(eventName, callback);
}
public filterOn(filterName: string, callback: FilterHandler) {
return this.emitter_.on(`filter:${filterName}`, callback);
}
public filterOff(filterName: string, callback: FilterHandler) {
return this.removeListener(`filter:${filterName}`, callback);
}
// eslint-disable-next-line @typescript-eslint/no-explicit-any -- Old code before rule was applied
public async filterEmit(filterName: string, object: any) {
let output = object;
const listeners = this.emitter_.listeners(`filter:${filterName}`);
for (const listener of listeners) {
// When we pass the object to the plugin, it is always going to be
// modified since it is serialized/unserialized. So we need to use a
// deep equality check to see if it's been changed. Normally the
// filter objects should be relatively small so there shouldn't be
// much of a performance hit.
const newOutput = await listener(output);
// Plugin didn't return anything - so we leave the object as it is.
if (newOutput === undefined) continue;
if (!fastDeepEqual(newOutput, output)) {
output = newOutput;
}
}
return output;
}
public appStateOn(propName: string, callback: AppStateChangeCallback) {
if (!this.appStateListeners_[propName]) {
this.appStateListeners_[propName] = [];
this.appStateWatchedProps_.push(propName);
}
this.appStateListeners_[propName].push(callback);
}
public appStateOff(propName: string, callback: AppStateChangeCallback) {
if (!this.appStateListeners_[propName]) {
throw new Error('EventManager: Trying to unregister a state prop watch for a non-watched prop (1)');
}
const idx = this.appStateListeners_[propName].indexOf(callback);
if (idx < 0) throw new Error('EventManager: Trying to unregister a state prop watch for a non-watched prop (2)');
this.appStateListeners_[propName].splice(idx, 1);
}
private stateValue_(state: AppState, propName: string) {
const parts = propName.split('.');
// eslint-disable-next-line @typescript-eslint/no-explicit-any -- Partially refactored old code from before rule was applied.
let s: any = state;
for (const p of parts) {
if (!(p in s)) throw new Error(`Invalid state property path: ${propName}`);
s = s[p];
}
return s;
}
// This function works by keeping a copy of the watched props and, whenever this function
// is called, comparing the previous and new values and emitting events if they have changed.
// The appStateEmit function should be called from a middleware.
public appStateEmit(state: AppState) {
if (!this.appStateWatchedProps_.length) return;
for (const propName of this.appStateWatchedProps_) {
let emit = false;
const stateValue = this.stateValue_(state, propName);
if (!(propName in this.appStatePrevious_) || this.appStatePrevious_[propName] !== stateValue) {
this.appStatePrevious_[propName] = stateValue;
emit = true;
}
if (emit) {
const listeners = this.appStateListeners_[propName];
if (!listeners || !listeners.length) continue;
const eventValue = Object.freeze(stateValue);
for (const listener of listeners) {
listener({ value: eventValue });
}
}
}
}
public once(eventName: string, callback: EventListenerCallback) {
return this.emitter_.once(eventName, callback);
}
// For testing only; only applies to listeners registered with .on.
public listenerCounter_(event: EventName) {
const initialListeners = this.emitter_.listeners(event);
return {
getCountRemoved: () => {
const currentListeners = this.emitter_.listeners(event);
let countRemoved = 0;
for (const listener of initialListeners) {
if (!currentListeners.includes(listener)) {
countRemoved ++;
}
}
return countRemoved;
},
};
}
}
const eventManager = new EventManager();
export default eventManager;