fix: memory leak in policy ipc

[SimonSiefke]

Fixes a memory leaks in policy ipc.

Details

There exists only one PolicyChannelServer and multiple PolicyChannelClients. Currenly, when a client listens, an event disposable gets the PolicyChannelServer disposables. But it doesn't seem to be removed when the client disconnects or gets disposed.

listen(_: unknown, event: string): Event<any> {
	switch (event) {
		case 'onDidChange': return Event.map(
			this.service.onDidChange,
			names => names.reduce<object>((r, name) => ({ ...r, [name]: this.service.getPolicyValue(name) ?? null }), {}),
			this.disposables // here
		);
	}
}

Change

By moving the _onDidChange event creation to the constructor, the event disposables are only added once to this.disposables. When a client listens, disposables are added to this.disposables.

Before

When opening and closing a window 17 times, the number of functions in PolicyChannel.listen seems to grow each time:

After

When opening and closing a window 17 times, the number of functions in PolicyChannel.listen stays constant: