isolate sample maintenance (#167)

* isolate sample maintenance

- use slightly more meaningful names
- rename files
- misc small readability changes

* update MAINTENANCE.md

* fix gh username

* formatting

* upgrade dependencies

isolate_example/lib/data_transfer_page.dart

@@ -142,7 +142,9 @@ class DataTransferIsolateController extends ChangeNotifier {
   }
 
   Future<void> generateRandomNumbers(bool transferableTyped) async {
-    if (running) return;
+    if (running) {
+      return;
+    }
 
     if (transferableTyped) {
       runningTest = 2;
@@ -150,7 +152,7 @@ class DataTransferIsolateController extends ChangeNotifier {
       runningTest = 1;
     }
 
-    Random rng = Random();
+    var random = Random();
 
     currentProgress.clear();
 
@@ -162,7 +164,7 @@ class DataTransferIsolateController extends ChangeNotifier {
       randNums.clear();
 
       for (int j = 0; j < 1000000; j++) {
-        randNums.add(rng.nextInt(100));
+        randNums.add(random.nextInt(100));
       }
 
       if (transferableTyped) {
@@ -221,28 +223,28 @@ class RunningList extends StatelessWidget {
   }
 }
 
-Future<void> _secondIsolateEntryPoint(SendPort callerSP) async {
-  ReceivePort newIceRP = ReceivePort();
-  callerSP.send(newIceRP.sendPort);
+Future<void> _secondIsolateEntryPoint(SendPort sendPort) async {
+  var receivePort = ReceivePort();
+  sendPort.send(receivePort.sendPort);
   int length = 1;
 
-  newIceRP.listen(
+  receivePort.listen(
     (dynamic message) async {
       if (message is String && message == 'start') {
-        await generateAndSum(callerSP, createNums(), length);
+        await generateAndSum(sendPort, createNums(), length);
 
-        callerSP.send('done');
+        sendPort.send('done');
       } else if (message is TransferableTypedData) {
         await generateAndSum(
-            callerSP, message.materialize().asInt32List(), length);
+            sendPort, message.materialize().asInt32List(), length);
         length++;
       } else if (message is List<int>) {
-        await generateAndSum(callerSP, message, length);
+        await generateAndSum(sendPort, message, length);
         length++;
       }
 
       if (length == 101) {
-        callerSP.send('done');
+        sendPort.send('done');
         length = 1;
       }
     },
@@ -250,9 +252,9 @@ Future<void> _secondIsolateEntryPoint(SendPort callerSP) async {
 }
 
 Iterable<int> createNums() sync* {
-  final rng = Random();
+  var random = Random();
   for (int i = 0; i < 100000000; i++) {
-    yield rng.nextInt(100);
+    yield random.nextInt(100);
   }
 }
 

isolate_example/lib/infinite_process_page.dart

@@ -102,7 +102,7 @@ class InfiniteProcessPage extends StatelessWidget {
 
 class InfiniteProcessIsolateController extends ChangeNotifier {
   Isolate newIsolate;
-  ReceivePort mIceRP;
+  ReceivePort receivePort;
   SendPort newIceSP;
   Capability capability;
 
@@ -120,12 +120,13 @@ class InfiniteProcessIsolateController extends ChangeNotifier {
   List<int> get currentResults => _currentResults;
 
   Future<void> createIsolate() async {
-    mIceRP = ReceivePort();
-    newIsolate = await Isolate.spawn(_secondIsolateEntryPoint, mIceRP.sendPort);
+    receivePort = ReceivePort();
+    newIsolate =
+        await Isolate.spawn(_secondIsolateEntryPoint, receivePort.sendPort);
   }
 
   void listen() {
-    mIceRP.listen((dynamic message) {
+    receivePort.listen((dynamic message) {
       if (message is SendPort) {
         newIceSP = message;
         newIceSP.send(_currentMultiplier);
@@ -224,7 +225,9 @@ Future<void> _secondIsolateEntryPoint(SendPort callerSP) async {
   callerSP.send(newIceRP.sendPort);
 
   newIceRP.listen((dynamic message) {
-    if (message is int) multiplyValue = message;
+    if (message is int) {
+      multiplyValue = message;
+    }
   });
 
   // This runs until the isolate is terminated.

isolate_example/lib/main.dart

@@ -14,19 +14,19 @@
 
 import 'package:flutter/material.dart';
 
-import 'page_one.dart';
-import 'page_three.dart';
-import 'page_two.dart';
+import 'data_transfer_page.dart';
+import 'infinite_process_page.dart';
+import 'performance_page.dart';
 
 void main() {
   runApp(
     MaterialApp(
-      home: StartApp(),
+      home: HomePage(),
     ),
   );
 }
 
-class StartApp extends StatelessWidget {
+class HomePage extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     return MaterialApp(

isolate_example/lib/performance_page.dart

@@ -17,15 +17,15 @@ import 'package:flutter/material.dart';
 
 // Computes the nth number in the Fibonacci sequence.
 int fib(int n) {
-  int number1 = n - 1;
-  int number2 = n - 2;
+  var a = n - 1;
+  var b = n - 2;
 
   if (n == 1) {
     return 0;
   } else if (n == 0) {
     return 1;
   } else {
-    return (fib(number1) + fib(number2));
+    return (fib(a) + fib(b));
   }
 }
 
@@ -49,25 +49,29 @@ class _PerformancePageState extends State<PerformancePage> {
             padding: EdgeInsets.only(top: 150),
             child: Column(
               children: [
-                FutureBuilder<void>(
+                FutureBuilder(
                   future: computeFuture,
                   builder: (context, snapshot) {
                     return RaisedButton(
                       child: const Text('Compute on Main'),
                       elevation: 8.0,
-                      onPressed: createMainIsolateCallBack(context, snapshot),
+                      onPressed:
+                          snapshot.connectionState == ConnectionState.done
+                              ? () => handleComputeOnMain(context)
+                              : null,
                     );
                   },
                 ),
-                FutureBuilder<void>(
+                FutureBuilder(
                   future: computeFuture,
                   builder: (context, snapshot) {
                     return RaisedButton(
-                      child: const Text('Compute on Secondary'),
-                      elevation: 8.0,
-                      onPressed:
-                          createSecondaryIsolateCallBack(context, snapshot),
-                    );
+                        child: const Text('Compute on Secondary'),
+                        elevation: 8.0,
+                        onPressed:
+                            snapshot.connectionState == ConnectionState.done
+                                ? () => handleComputeOnSecondary(context)
+                                : null);
                   },
                 ),
               ],
@@ -78,54 +82,40 @@ class _PerformancePageState extends State<PerformancePage> {
     );
   }
 
-  VoidCallback createMainIsolateCallBack(
-    BuildContext context,
-    AsyncSnapshot snapshot,
-  ) {
-    if (snapshot.connectionState == ConnectionState.done) {
-      return () {
-        setState(() {
-          computeFuture = computeOnMainIsolate()
-            ..then((_) {
-              final snackBar = SnackBar(
-                content: Text('Main Isolate Done!'),
-              );
-              Scaffold.of(context).showSnackBar(snackBar);
-            });
-        });
-      };
-    } else {
-      return null;
-    }
+  void handleComputeOnMain(BuildContext context) {
+    var future = computeOnMainIsolate()
+      ..then((_) {
+        var snackBar = SnackBar(
+          content: Text('Main Isolate Done!'),
+        );
+        Scaffold.of(context).showSnackBar(snackBar);
+      });
+
+    setState(() {
+      computeFuture = future;
+    });
   }
 
-  VoidCallback createSecondaryIsolateCallBack(
-      BuildContext context, AsyncSnapshot snapshot) {
-    if (snapshot.connectionState == ConnectionState.done) {
-      return () {
-        setState(() {
-          computeFuture = computeOnSecondaryIsolate()
-            ..then((_) {
-              final snackBar = SnackBar(
-                content: Text('Secondary Isolate Done!'),
-              );
-              Scaffold.of(context).showSnackBar(snackBar);
-            });
-        });
-      };
-    } else {
-      return null;
-    }
+  void handleComputeOnSecondary(BuildContext context) {
+    var future = computeOnSecondaryIsolate()
+      ..then((_) {
+        var snackBar = SnackBar(
+          content: Text('Secondary Isolate Done!'),
+        );
+        Scaffold.of(context).showSnackBar(snackBar);
+      });
+
+    setState(() {
+      computeFuture = future;
+    });
   }
 
   Future<void> computeOnMainIsolate() async {
-    // A delay is added here to give Flutter the chance to redraw the UI at least
-    // once before the computation (which, since it's run on the main isolate,
-    // will lock up the app) begins executing.
-    await Future.delayed(
-      Duration(milliseconds: 100),
-      () => fib(45),
-    );
+    // A delay is added here to give Flutter the chance to redraw the UI at
+    // least once before the computation (which, since it's run on the main
+    // isolate, will lock up the app) begins executing.
+    await Future<void>.delayed(Duration(milliseconds: 100));
+    fib(45);
   }
 
   Future<void> computeOnSecondaryIsolate() async {
@@ -141,24 +131,22 @@ class SmoothAnimationWidget extends StatefulWidget {
 
 class SmoothAnimationWidgetState extends State<SmoothAnimationWidget>
     with TickerProviderStateMixin {
-  AnimationController _controller;
+  AnimationController _animationController;
   Animation<BorderRadius> _borderAnimation;
 
   @override
   void initState() {
     super.initState();
 
-    _controller = AnimationController(
-      duration: const Duration(seconds: 1),
-      vsync: this,
-    );
+    _animationController =
+        AnimationController(duration: const Duration(seconds: 1), vsync: this);
 
     _borderAnimation = BorderRadiusTween(
-      begin: BorderRadius.circular(100.0),
-      end: BorderRadius.circular(0.0),
-    ).animate(_controller);
+            begin: BorderRadius.circular(100.0),
+            end: BorderRadius.circular(0.0))
+        .animate(_animationController);
 
-    _controller.repeat(reverse: true);
+    _animationController.repeat(reverse: true);
   }
 
   @override
@@ -192,7 +180,7 @@ class SmoothAnimationWidgetState extends State<SmoothAnimationWidget>
 
   @override
   void dispose() {
-    _controller.dispose();
+    _animationController.dispose();
     super.dispose();
   }
 }

isolate_example/pubspec.lock

@@ -73,7 +73,7 @@ packages:
       name: provider
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "3.1.0"
+    version: "3.1.0+1"
   quiver:
     dependency: transitive
     description: