80 lines
1.9 KiB
Dart
80 lines
1.9 KiB
Dart
import 'dart:async';
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import 'package:flutter/foundation.dart';
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typedef EventCallback<Data> = Future<dynamic> Function(Data data);
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abstract class BaseEvent<EventType, Data> {
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EventType type;
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Data data;
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/// Constructor.
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BaseEvent(this.type, this.data);
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/// Consume this event.
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@visibleForTesting
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Future<dynamic> consume() async {
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final cb = findCallback(type);
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if (cb == null) {
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return null;
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} else {
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return cb(data);
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}
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}
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EventCallback<Data>? findCallback(EventType type);
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}
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abstract class BaseEventLoop<EventType, Data> {
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final List<BaseEvent<EventType, Data>> _evts = [];
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Timer? _timer;
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List<BaseEvent<EventType, Data>> get evts => _evts;
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Future<void> onReady() async {
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// Poll every 100ms.
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_timer = Timer.periodic(Duration(milliseconds: 100), _handleTimer);
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}
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/// An Event is about to be consumed.
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Future<void> onPreConsume(BaseEvent<EventType, Data> evt) async {}
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/// An Event was consumed.
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Future<void> onPostConsume(BaseEvent<EventType, Data> evt) async {}
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/// Events are all handled and cleared.
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Future<void> onEventsClear() async {}
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/// Events start to consume.
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Future<void> onEventsStartConsuming() async {}
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Future<void> _handleTimer(Timer timer) async {
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if (_evts.isEmpty) {
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return;
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}
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timer.cancel();
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_timer = null;
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// Handle the logic.
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await onEventsStartConsuming();
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while (_evts.isNotEmpty) {
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final evt = _evts.first;
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_evts.remove(evt);
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await onPreConsume(evt);
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await evt.consume();
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await onPostConsume(evt);
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}
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await onEventsClear();
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// Now events are all processed.
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_timer = Timer.periodic(Duration(milliseconds: 100), _handleTimer);
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}
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Future<void> close() async {
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_timer?.cancel();
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}
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void pushEvent(BaseEvent<EventType, Data> evt) {
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_evts.add(evt);
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}
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void clear() {
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_evts.clear();
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}
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}
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