isolatengine 0.0.7

isolate communication engine.

example/lib/main.dart

import 'dart:async';
import 'dart:developer';
import 'dart:isolate';

import 'package:cancelable/cancelable.dart';
import 'package:flutter/material.dart';
import 'package:isolatengine/isolatengine.dart';

void main() {
  runApp(const MyApp());
}

void _entry(SendPort sendPort) async {
  final receivePort = ReceivePort();
  final engine = Isolatengine(receivePort, sendPort);
  engine['download'] = (param, cancelable, notify) async {
    var i = 0;
    final completer = Completer();
    StreamSubscription? sub;
    final timer = Timer.periodic(const Duration(seconds: 1), (timer) {
      final p = '${++i}/10';
      notify(p);
      if (i != 10) {
        return;
      }
      completer.complete();
    });
    cancelable.whenCancel(() {
      completer.completeError('cancelled');
    });
    try {
      await completer.future;
      sub?.cancel();
      timer.cancel();
    } catch (_) {
      sub?.cancel();
      timer.cancel();
      rethrow;
    }
    return null;
  };
  await engine.receive();
}

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        // This is the theme of your application.
        //
        // Try running your application with "flutter run". You'll see the
        // application has a blue toolbar. Then, without quitting the app, try
        // changing the primarySwatch below to Colors.green and then invoke
        // "hot reload" (press "r" in the console where you ran "flutter run",
        // or simply save your changes to "hot reload" in a Flutter IDE).
        // Notice that the counter didn't reset back to zero; the application
        // is not restarted.
        primarySwatch: Colors.blue,
      ),
      home: const MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({Key? key, required this.title}) : super(key: key);

  // This widget is the home page of your application. It is stateful, meaning
  // that it has a State object (defined below) that contains fields that affect
  // how it looks.

  // This class is the configuration for the state. It holds the values (in this
  // case the title) provided by the parent (in this case the App widget) and
  // used by the build method of the State. Fields in a Widget subclass are
  // always marked "final".

  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  String _text = "";
  Cancelable? _cancelable;
  final Isolatengine _engine = () {
    final receivePort = ReceivePort();
    final v = Isolatengine(receivePort);
    v.log = (name, data) {
      log(data.toString(), name: name);
    };
    Isolate.spawn(_entry, receivePort.sendPort);
    v.receive();
    return v;
  }();

  void _click() async {
    if (_cancelable != null) {
      _cancelable?.cancel();
      return;
    }
    _cancelable = Cancelable();
    setState(() {
      _text = "starting";
    });
    try {
      await _engine.deliver('download', cancelable: _cancelable, onNotify: (param) {
        if (param is String) {
          setState(() {
            _text = param;
          });
        }
      });
      setState(() {
        _text = "finished";
      });
    } catch (e) {
      setState(() {
        _text = e.toString();
      });
    }
    _cancelable = null;
  }

  @override
  Widget build(BuildContext context) {
    // This method is rerun every time setState is called, for instance as done
    // by the _incrementCounter method above.
    //
    // The Flutter framework has been optimized to make rerunning build methods
    // fast, so that you can just rebuild anything that needs updating rather
    // than having to individually change instances of widgets.
    return Scaffold(
      appBar: AppBar(
        // Here we take the value from the MyHomePage object that was created by
        // the App.build method, and use it to set our appbar title.
        title: Text(widget.title),
      ),
      body: Center(
        // Center is a layout widget. It takes a single child and positions it
        // in the middle of the parent.
        child: Column(
          // Column is also a layout widget. It takes a list of children and
          // arranges them vertically. By default, it sizes itself to fit its
          // children horizontally, and tries to be as tall as its parent.
          //
          // Invoke "debug painting" (press "p" in the console, choose the
          // "Toggle Debug Paint" action from the Flutter Inspector in Android
          // Studio, or the "Toggle Debug Paint" command in Visual Studio Code)
          // to see the wireframe for each widget.
          //
          // Column has various properties to control how it sizes itself and
          // how it positions its children. Here we use mainAxisAlignment to
          // center the children vertically; the main axis here is the vertical
          // axis because Columns are vertical (the cross axis would be
          // horizontal).
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            const Text(
              'Isolatengine',
            ),
            Text(
              _text,
              style: Theme.of(context).textTheme.headline4,
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _click,
        tooltip: 'click',
        child: const Icon(Icons.download),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }
}