lib/src/common.dart - dart-services - Git at Google

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.

 import 'dart:io';

 const kMainDart = 'main.dart';
 const kBootstrapDart = 'bootstrap.dart';

 /// This code should be kept up-to-date with WebEntrypointTarget.build() from
 /// flutter_tools: https://github.com/flutter/flutter/blob/169020719bc5882e746b836629721644633b6c8a/packages/flutter_tools/lib/src/build_system/targets/web.dart#L137
 const kBootstrapFlutterCode = r'''
 import 'dart:ui' as ui;
 import 'package:flutter_web_plugins/flutter_web_plugins.dart';
 import 'generated_plugin_registrant.dart';
 import 'main.dart' as entrypoint;

 Future<void> main() async {
   registerPlugins(webPluginRegistrar);
   await ui.webOnlyInitializePlatform();
   entrypoint.main();
 }
 ''';

 const kBootstrapDartCode = r'''
 import 'main.dart' as user_code;

 void main() {
   user_code.main();
 }
 ''';

 const sampleCode = '''
 void main() {
   print("hello");
 }
 ''';

 const sampleCodeWeb = """
 import 'dart:html';

 void main() {
   print("hello");
   querySelector('#foo')?.text = 'bar';
 }
 """;

 const sampleCodeFlutter = '''
 import 'package:flutter/material.dart';

 void main() async {
   runApp(
     MaterialApp(
       debugShowCheckedModeBanner: false,
       home: Scaffold(
         appBar: AppBar(
           title: const Text('Hey there, boo!'),
         ),
         body: const Center(
           child: Text(
             'You are pretty okay.',
           ),
         ),
       ),
     ),
   );
 }
 ''';

 // From https://gist.github.com/johnpryan/1a28bdd9203250d3226cc25d512579ec
 const sampleCodeFlutterCounter = r'''
 import 'package:flutter/material.dart';

 void main() => runApp(MyApp());

 class MyApp extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     return MaterialApp(
       title: 'Flutter Demo',
       debugShowCheckedModeBanner: false,
       theme: ThemeData(
         primarySwatch: Colors.blue,
       ),
       home: const MyHomePage(title: 'Flutter Demo Home Page'),
     );
   }
 }

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

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

 class _MyHomePageState extends State<MyHomePage> {
   int _counter = 0;

   void _incrementCounter() {
     setState(() {
       _counter++;
     });
   }

   @override
   Widget build(BuildContext context) {
     return Scaffold(
       appBar: AppBar(
         title: Text(widget.title),
       ),
       body: Center(
         child: Column(
           mainAxisAlignment: MainAxisAlignment.center,
           children: <Widget>[
             const Text(
               'You have pushed the button this many times:',
             ),
             Text(
               '$_counter',
               style: Theme.of(context).textTheme.headlineMedium,
             ),
           ],
         ),
       ),
       floatingActionButton: FloatingActionButton(
         onPressed: _incrementCounter,
         tooltip: 'Increment',
         child: const Icon(Icons.add),
       ),
     );
   }
 }
 ''';

 // From https://gist.github.com/RedBrogdon/e0a2e942e85fde2cd39b2741ff0c49e5
 const sampleCodeFlutterSunflower = r'''
 import 'dart:math' as math;
 import 'package:flutter/material.dart';

 const Color primaryColor = Colors.orange;
 const TargetPlatform platform = TargetPlatform.android;

 void main() {
   runApp(Sunflower());
 }

 class SunflowerPainter extends CustomPainter {
   static const seedRadius = 2.0;
   static const scaleFactor = 4;
   static const tau = math.pi * 2;

   static final phi = (math.sqrt(5) + 1) / 2;

   final int seeds;

   SunflowerPainter(this.seeds);

   @override
   void paint(Canvas canvas, Size size) {
     final center = size.width / 2;

     for (var i = 0; i < seeds; i++) {
       final theta = i * tau / phi;
       final r = math.sqrt(i) * scaleFactor;
       final x = center + r * math.cos(theta);
       final y = center - r * math.sin(theta);
       final offset = Offset(x, y);
       if (!size.contains(offset)) {
         continue;
       }
       drawSeed(canvas, x, y);
     }
   }

   @override
   bool shouldRepaint(SunflowerPainter oldDelegate) {
     return oldDelegate.seeds != seeds;
   }

   // Draw a small circle representing a seed centered at (x,y).
   void drawSeed(Canvas canvas, double x, double y) {
     final paint = Paint()
       ..strokeWidth = 2
       ..style = PaintingStyle.fill
       ..color = primaryColor;
     canvas.drawCircle(Offset(x, y), seedRadius, paint);
   }
 }

 class Sunflower extends StatefulWidget {
   @override
   State<Sunflower> createState() {
     return _SunflowerState();
   }
 }

 class _SunflowerState extends State<Sunflower> {
   double seeds = 100.0;

   int get seedCount => seeds.floor();

   @override
   Widget build(BuildContext context) {
     return MaterialApp(
       debugShowCheckedModeBanner: false,
       theme: ThemeData().copyWith(
         platform: platform,
         brightness: Brightness.dark,
         sliderTheme: SliderThemeData.fromPrimaryColors(
           primaryColor: primaryColor,
           primaryColorLight: primaryColor,
           primaryColorDark: primaryColor,
           valueIndicatorTextStyle: const DefaultTextStyle.fallback().style,
         ),
       ),
       home: Scaffold(
         appBar: AppBar(title: const Text("Sunflower")),
         drawer: Drawer(
             child: ListView(
           children: const [
             DrawerHeader(
               child: Center(
                 child: Text(
                   "Sunflower 🌻",
                   style: TextStyle(fontSize: 32),
                 ),
               ),
             ),
           ],
         )),
         body: Container(
           constraints: const BoxConstraints.expand(),
           decoration:
               BoxDecoration(border: Border.all(color: Colors.transparent)),
           child: Column(
             crossAxisAlignment: CrossAxisAlignment.center,
             mainAxisAlignment: MainAxisAlignment.start,
             children: [
               Container(
                 decoration: BoxDecoration(
                     border: Border.all(color: Colors.transparent)),
                 child: SizedBox(
                   width: 400,
                   height: 400,
                   child: CustomPaint(
                     painter: SunflowerPainter(seedCount),
                   ),
                 ),
               ),
               Text("Showing $seedCount seeds"),
               ConstrainedBox(
                 constraints: const BoxConstraints.tightFor(width: 300),
                 child: Slider.adaptive(
                   min: 20,
                   max: 2000,
                   value: seeds,
                   onChanged: (newValue) {
                     setState(() {
                       seeds = newValue;
                     });
                   },
                 ),
               ),
             ],
           ),
         ),
       ),
     );
   }
 }
 ''';

 // https://gist.github.com/johnpryan/5e28c5273c2c1a41d30bad9f9d11da56
 const sampleCodeFlutterDraggableCard = '''
 import 'package:flutter/material.dart';
 import 'package:flutter/physics.dart';

 main() {
   runApp(
     MaterialApp(
       debugShowCheckedModeBanner: false,
       home: PhysicsCardDragDemo(),
     ),
   );
 }

 class PhysicsCardDragDemo extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     return Scaffold(
       appBar: AppBar(
         title: const Text('A draggable card!'),
       ),
       body: const DraggableCard(
         child: FlutterLogo(
           size: 128,
         ),
       ),
     );
   }
 }

 class DraggableCard extends StatefulWidget {
   final Widget child;
   const DraggableCard({required this.child});

   @override
   State<DraggableCard> createState() => _DraggableCardState();
 }

 class _DraggableCardState extends State<DraggableCard>
     with SingleTickerProviderStateMixin {
   AnimationController? _controller;
   Alignment _dragAlignment = Alignment.center;
   Animation<Alignment>? _animation;

   void _runAnimation(Offset pixelsPerSecond, Size size) {
     _animation = _controller!.drive(
       AlignmentTween(
         begin: _dragAlignment,
         end: Alignment.center,
       ),
     );

     final unitsPerSecondX = pixelsPerSecond.dx / size.width;
     final unitsPerSecondY = pixelsPerSecond.dy / size.height;
     final unitsPerSecond = Offset(unitsPerSecondX, unitsPerSecondY);
     final unitVelocity = unitsPerSecond.distance;

     const spring = SpringDescription(
       mass: 30,
       stiffness: 1,
       damping: 1,
     );

     final simulation = SpringSimulation(spring, 0, 1, -unitVelocity);

     _controller!.animateWith(simulation);
   }

   @override
   void initState() {
     super.initState();
     _controller = AnimationController(vsync: this);

     _controller!.addListener(() {
       setState(() {
         _dragAlignment = _animation!.value;
       });
     });
   }

   @override
   void dispose() {
     _controller!.dispose();
     super.dispose();
   }

   @override
   Widget build(BuildContext context) {
     final size = MediaQuery.of(context).size;
     return GestureDetector(
       onPanDown: (details) {
         _controller!.stop();
       },
       onPanUpdate: (details) {
         setState(() {
           _dragAlignment += Alignment(
             details.delta.dx / (size.width / 2),
             details.delta.dy / (size.height / 2),
           );
         });
       },
       onPanEnd: (details) {
         _runAnimation(details.velocity.pixelsPerSecond, size);
       },
       child: Align(
         alignment: _dragAlignment,
         child: Card(
           child: widget.child,
         ),
       ),
     );
   }
 }
 ''';

 // From https://gist.github.com/johnpryan/289ecf8480ad005f01faeace70bd529a
 const sampleCodeFlutterImplicitAnimations = '''
 import 'dart:math';
 import 'package:flutter/material.dart';

 class DiscData {
   static final _rng = Random();

   final double size;
   final Color color;
   final Alignment alignment;

   DiscData()
       : size = _rng.nextDouble() * 40 + 10,
         color = Color.fromARGB(
           _rng.nextInt(200),
           _rng.nextInt(255),
           _rng.nextInt(255),
           _rng.nextInt(255),
         ),
         alignment = Alignment(
           _rng.nextDouble() * 2 - 1,
           _rng.nextDouble() * 2 - 1,
         );
 }

 void main() async {
   runApp(
     MaterialApp(
       debugShowCheckedModeBanner: false,
       home: Scaffold(
         body: Container(
           color: const Color(0xFF15202D),
           child: const SizedBox.expand(
             child: VariousDiscs(50),
           ),
         ),
       ),
     ),
   );
 }

 class VariousDiscs extends StatefulWidget {
   final int numberOfDiscs;

   const VariousDiscs(this.numberOfDiscs);

   @override
   State<VariousDiscs> createState() => _VariousDiscsState();
 }

 class _VariousDiscsState extends State<VariousDiscs> {
   final _discs = <DiscData>[];

   @override
   void initState() {
     super.initState();
     _makeDiscs();
   }

   void _makeDiscs() {
     _discs.clear();
     for (int i = 0; i < widget.numberOfDiscs; i++) {
       _discs.add(DiscData());
     }
   }

   @override
   Widget build(BuildContext context) {
     return GestureDetector(
       onTap: () => setState(() {
         _makeDiscs();
       }),
       child: Stack(
         children: [
           const Center(
             child: Text(
               'Click a disc!',
               style: TextStyle(color: Colors.white, fontSize: 50),
             ),
           ),
           for (final disc in _discs)
             Positioned.fill(
               child: AnimatedAlign(
                 duration: const Duration(milliseconds: 500),
                 curve: Curves.easeInOut,
                 alignment: disc.alignment,
                 child: AnimatedContainer(
                   duration: const Duration(milliseconds: 500),
                   decoration: BoxDecoration(
                     color: disc.color,
                     shape: BoxShape.circle,
                   ),
                   height: disc.size,
                   width: disc.size,
                 ),
               ),
             ),
         ],
       ),
     );
   }
 }
 ''';

 const sampleCodeMultiFoo = """
 import 'bar.dart';

 void main() {
   print(bar());
 }
 """;

 const sampleCodeMultiBar = '''
 bar() {
   return 4;
 }
 ''';

 const sampleCodeLibraryMultiFoo = """
 library foofoo;

 part 'bar.dart';

 void main() {
   print(bar());
 }
 """;

 const sampleCodePartMultiBar = '''
 part of foofoo;

 bar() {
   return 4;
 }
 ''';

 const sampleCodeAsync = """
 import 'dart:html';

 void main() async {
   print("hello");
   querySelector('#foo')?.text = 'bar';
   var foo = await HttpRequest.getString('http://www.google.com');
   print(foo);
 }
 """;

 const sampleCodeError = '''
 void main() {
   print("hello")
 }
 ''';

 const sampleCodeErrors = '''
 void main() {
   print1("hello");
   print2("hello");
   print3("hello");
 }
 ''';

 const sampleDart2Error = '''
 class Foo {
   final bool isAlwaysNull;
   Foo(this.isAlwaysNull) {}
 }

 void main(List<String> argv) {
   var x = new Foo(null);
   var y = 1;
   y = x;
 }
 ''';

 /// Code fragments for testing multi file compiling.
 /// These fragments are taken from [sampleCodeFlutterImplicitAnimations] and
 /// only separated and re-arranged to facilitate testing multi file tests.

 const sampleCode3PartFlutterImplicitAnimationsImports = r'''
 import 'dart:math';
 import 'package:flutter/material.dart';
 ''';

 const sampleCode3PartFlutterImplicitAnimationsMain = r'''

 void main() async {
   runApp(
     MaterialApp(
       debugShowCheckedModeBanner: false,
       home: Scaffold(
         body: Container(
           color: const Color(0xFF15202D),
           child: const SizedBox.expand(
             child: VariousDiscs(50),
           ),
         ),
       ),
     ),
   );
 }
 ''';

 const sampleCode3PartFlutterImplicitAnimationsDiscData = r'''

 class DiscData {
   static final _rng = Random();

   final double size;
   final Color color;
   final Alignment alignment;

   DiscData()
       : size = _rng.nextDouble() * 40 + 10,
         color = Color.fromARGB(
           _rng.nextInt(200),
           _rng.nextInt(255),
           _rng.nextInt(255),
           _rng.nextInt(255),
         ),
         alignment = Alignment(
           _rng.nextDouble() * 2 - 1,
           _rng.nextDouble() * 2 - 1,
         );
 }
 ''';

 const sampleCode3PartFlutterImplicitAnimationsVarious = r'''

 class VariousDiscs extends StatefulWidget {
   final int numberOfDiscs;

   const VariousDiscs(this.numberOfDiscs);

   @override
   State<VariousDiscs> createState() => _VariousDiscsState();
 }

 class _VariousDiscsState extends State<VariousDiscs> {
   final _discs = <DiscData>[];

   @override
   void initState() {
     super.initState();
     _makeDiscs();
   }

   void _makeDiscs() {
     _discs.clear();
     for (int i = 0; i < widget.numberOfDiscs; i++) {
       _discs.add(DiscData());
     }
   }

   @override
   Widget build(BuildContext context) {
     return GestureDetector(
       onTap: () => setState(() {
         _makeDiscs();
       }),
       child: Stack(
         children: [
           const Center(
             child: Text(
               'Click a disc!',
               style: TextStyle(color: Colors.white, fontSize: 50),
             ),
           ),
           for (final disc in _discs)
             Positioned.fill(
               child: AnimatedAlign(
                 duration: const Duration(milliseconds: 500),
                 curve: Curves.easeInOut,
                 alignment: disc.alignment,
                 child: AnimatedContainer(
                   duration: const Duration(milliseconds: 500),
                   decoration: BoxDecoration(
                     color: disc.color,
                     shape: BoxShape.circle,
                   ),
                   height: disc.size,
                   width: disc.size,
                 ),
               ),
             ),
         ],
       ),
     );
   }
 }
 ''';

 /// Create 2 files for multi file testing using imports.
 const sampleCode2PartImportMain = '''
 $sampleCode3PartFlutterImplicitAnimationsImports
 import 'various.dart';
 $sampleCode3PartFlutterImplicitAnimationsMain
 ''';

 const sampleCode2PartImportVarious = '''
 $sampleCode3PartFlutterImplicitAnimationsImports
 $sampleCode3PartFlutterImplicitAnimationsDiscData
 $sampleCode3PartFlutterImplicitAnimationsVarious
 ''';

 /// Create 3 separate files for multi file testing using imports.
 /// Here main.dart will be importing 'various.dart' and 'discdata.dart',
 /// and 'various.dart' importing 'discdata.dart'.
 const sampleCode3PartImportMain = '''
 $sampleCode3PartFlutterImplicitAnimationsImports
 import 'various.dart';
 import 'discdata.dart';
 $sampleCode3PartFlutterImplicitAnimationsMain
 ''';

 const sampleCode3PartImportDiscData = '''
 $sampleCode3PartFlutterImplicitAnimationsImports
 $sampleCode3PartFlutterImplicitAnimationsDiscData
 ''';

 const sampleCode3PartImportVarious = '''
 $sampleCode3PartFlutterImplicitAnimationsImports
 import 'discdata.dart';
 $sampleCode3PartFlutterImplicitAnimationsVarious
 ''';

 /// Create 2 file test using "part 'various.dart'" to bring in second file.
 const sampleCode2PartLibraryMain = '''
 library testanim;
 $sampleCode3PartFlutterImplicitAnimationsImports
 part 'various.dart';
 $sampleCode3PartFlutterImplicitAnimationsMain
 ''';

 const sampleCode2PartVariousAndDiscDataPartOfTestAnim = '''
 part of testanim;
 $sampleCode3PartFlutterImplicitAnimationsDiscData
 $sampleCode3PartFlutterImplicitAnimationsVarious
 ''';

 /// Create 3 file test using "part 'various.dart'" and "part 'discdata.dart'"
 /// to bring in second and third files.
 const sampleCode3PartLibraryMain = '''
 library testanim;
 $sampleCode3PartFlutterImplicitAnimationsImports
 part 'discdata.dart';
 part 'various.dart';
 $sampleCode3PartFlutterImplicitAnimationsMain
 ''';

 const sampleCode3PartDiscDataPartOfTestAnim = '''
 part of testanim;
 $sampleCode3PartFlutterImplicitAnimationsDiscData
 ''';

 const sampleCode3PartVariousPartOfTestAnim = '''
 part of testanim;
 $sampleCode3PartFlutterImplicitAnimationsVarious
 ''';

 class Lines {
   final List<int> _starts = <int>[];

   Lines(String source) {
     final units = source.codeUnits;
     for (var i = 0; i < units.length; i++) {
       if (units[i] == 10) _starts.add(i);
     }
   }

   /// Return the 0-based line number.
   int getLineForOffset(int offset) {
     for (var i = 0; i < _starts.length; i++) {
       if (offset <= _starts[i]) return i;
     }
     return _starts.length;
   }
 }

 /// Returns the version of the current Dart runtime.
 ///
 /// The returned `String` is formatted as the [semver](http://semver.org) version
 /// string of the current Dart runtime, possibly followed by whitespace and other
 /// version and build details.
 String get vmVersion => Platform.version;

 /// If [str] has leading and trailing quotes, remove them.
 String stripMatchingQuotes(String str) {
   if (str.length <= 1) return str;

   if (str.startsWith("'") && str.endsWith("'")) {
     str = str.substring(1, str.length - 1);
   } else if (str.startsWith('"') && str.endsWith('"')) {
     str = str.substring(1, str.length - 1);
   }
   return str;
 }

 class _SourcesGroupFile {
   String filename;
   String content;

   _SourcesGroupFile(this.filename, this.content);
 }

 ///This RegExp matches a variety of possible `main` function definition formats
 ///Like:
 /// - `Future<void> main(List<String> args) async {`
 /// - `void main(List<String> args) async {`
 /// - `void main() {`
 /// - `void main( List < String >  args ) async {`
 /// - `void main(Args arg) {`
 /// - `main() {`
 /// - `void main() {}`
 /// - `void main() => runApp(MyApp());`
 final RegExp mainFunctionDefinition = RegExp(
     r'''[\s]*(Future)?[\<]?(void)?[\>]?[\s]*main[\s]*\((\s*\w*\s*\<?\s*\w*\s*\>?\s*\w*\s*)?\)\s*(async)?\s*[\{|\=]+''');

 /// Used to remove 2 or more '..' and any number of following slashes of '/' or '\'.
 final RegExp sanitizeUpDirectories = RegExp(r'[\.]{2,}[\\\/]*');

 /// Used to remove 'package:', 'dart:', 'http://', 'https://' etc.
 final RegExp sanitizePackageDartHttp = RegExp(r'[\w]*[\:][\/]*');

 /// Sanitizes [filename] by using the regular expressions
 /// [sanitizeUpDirectories] and [sanitizePackageDartHttp] to remove
 /// anything like 'package:', 'dart:' or 'http://', and then removing
 /// runs of more than a single '.' (do not allow '..' up directories to
 /// escape temp directory).
 String _sanitizeFileName(String filename) {
   filename = filename.replaceAll(sanitizePackageDartHttp, '');
   filename = filename.replaceAll(sanitizeUpDirectories, '');
   return filename;
 }

 /// Goes through [sources] map of source files and sanitizes the filenames
 /// and ensures that the file containing the main entry point that bootstrap
 /// will be calling is called [kMainDart].
 /// [sources] is a map containing the source files in the format
 ///   `{ "filename1":"sourcecode1" .. "filenameN":"sourcecodeN"}`.
 /// [activeSourceName] is the name of the source file active in the editor.
 /// Returns [activeSourceName] or a new name if sanitized or renamed.
 String sanitizeAndCheckFilenames(Map<String, String> sources,
     [String activeSourceName = kMainDart]) {
   activeSourceName = _sanitizeFileName(activeSourceName);

   final files =
       sources.entries.map((e) => _SourcesGroupFile(e.key, e.value)).toList();

   var foundKMain = false;
   // Check for kMainDart file and also sanitize filenames.
   for (final sourceFile in files) {
     sourceFile.filename = _sanitizeFileName(sourceFile.filename);
     if (sourceFile.filename == kMainDart) {
       foundKMain = true;
     }
   }
   // One of the files must be named kMainDart. This is the file that the
   // bootstrap dart file will import and call main() on.
   if (!foundKMain && files.isNotEmpty) {
     // We need to rename the file containing the main() function to kMainDart.
     for (final sourceFile in files) {
       if (mainFunctionDefinition.hasMatch(sourceFile.content)) {
         // This file has a main() function, rename it to kMainDart
         // and also change activeSourceName if that is the file being
         // renamed.
         if (sourceFile.filename == activeSourceName) {
           activeSourceName = kMainDart;
         }
         sourceFile.filename = kMainDart;
         foundKMain = true;
         break;
       }
     }
     if (!foundKMain) {
       // No kMainDart was found so just change the first file to be kMainDart.
       if (files[0].filename == activeSourceName) {
         activeSourceName = kMainDart;
       }
       files[0].filename = kMainDart;
     }
   }

   // Take our files list and create a new files {filename:content} map.
   sources.clear();
   for (final sourceFiles in files) {
     sources[sourceFiles.filename] = sourceFiles.content;
   }

   return activeSourceName;
 }

 /// Count the total lines across all files in [sources] file map.
 int countLines(Map<String, String> sources) {
   var totalLines = 0;
   for (final filename in sources.keys) {
     totalLines += countLinesInString(sources[filename]!);
   }
   return totalLines;
 }

 // Character constants.
 const int _lf = 10;
 const int _cr = 13;

 /// Count lines in string (CR, LF or CR-LF can be line separators).
 /// (Gives correct result as opposed to .split('\n').length, which
 /// reports 1 extra line in many cases, and this does so without the
 /// extra work .split() would do by creating the list of copied strings).
 int countLinesInString(String str) {
   final data = str.codeUnits;
   var lines = 0;
   final end = data.length;
   var sliceStart = 0;
   var char = 0;
   for (var i = 0; i < end; i++) {
     final previousChar = char;
     char = data[i];
     if (char != _cr) {
       if (char != _lf) continue;
       if (previousChar == _cr) {
         sliceStart = i + 1;
         continue;
       }
     }
     lines++;
     sliceStart = i + 1;
   }
   if (sliceStart < end) {
     lines++;
   }
   return lines;
 }
	// Copyright (c) 2014, the Dart project authors. Please see the AUTHORS file
	// for details. All rights reserved. Use of this source code is governed by a
	// BSD-style license that can be found in the LICENSE file.

	import 'dart:io';

	const kMainDart = 'main.dart';
	const kBootstrapDart = 'bootstrap.dart';

	/// This code should be kept up-to-date with WebEntrypointTarget.build() from
	/// flutter_tools: https://github.com/flutter/flutter/blob/169020719bc5882e746b836629721644633b6c8a/packages/flutter_tools/lib/src/build_system/targets/web.dart#L137
	const kBootstrapFlutterCode = r'''
	import 'dart:ui' as ui;
	import 'package:flutter_web_plugins/flutter_web_plugins.dart';
	import 'generated_plugin_registrant.dart';
	import 'main.dart' as entrypoint;

	Future<void> main() async {
	registerPlugins(webPluginRegistrar);
	await ui.webOnlyInitializePlatform();
	entrypoint.main();
	}
	''';

	const kBootstrapDartCode = r'''
	import 'main.dart' as user_code;

	void main() {
	user_code.main();
	}
	''';

	const sampleCode = '''
	void main() {
	print("hello");
	}
	''';

	const sampleCodeWeb = """
	import 'dart:html';

	void main() {
	print("hello");
	querySelector('#foo')?.text = 'bar';
	}
	""";

	const sampleCodeFlutter = '''
	import 'package:flutter/material.dart';

	void main() async {
	runApp(
	MaterialApp(
	debugShowCheckedModeBanner: false,
	home: Scaffold(
	appBar: AppBar(
	title: const Text('Hey there, boo!'),
	),
	body: const Center(
	child: Text(
	'You are pretty okay.',
	),
	),
	),
	),
	);
	}
	''';

	// From https://gist.github.com/johnpryan/1a28bdd9203250d3226cc25d512579ec
	const sampleCodeFlutterCounter = r'''
	import 'package:flutter/material.dart';

	void main() => runApp(MyApp());

	class MyApp extends StatelessWidget {
	@override
	Widget build(BuildContext context) {
	return MaterialApp(
	title: 'Flutter Demo',
	debugShowCheckedModeBanner: false,
	theme: ThemeData(
	primarySwatch: Colors.blue,
	),
	home: const MyHomePage(title: 'Flutter Demo Home Page'),
	);
	}
	}

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

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

	class _MyHomePageState extends State<MyHomePage> {
	int _counter = 0;

	void _incrementCounter() {
	setState(() {
	_counter++;
	});
	}

	@override
	Widget build(BuildContext context) {
	return Scaffold(
	appBar: AppBar(
	title: Text(widget.title),
	),
	body: Center(
	child: Column(
	mainAxisAlignment: MainAxisAlignment.center,
	children: <Widget>[
	const Text(
	'You have pushed the button this many times:',
	),
	Text(
	'$_counter',
	style: Theme.of(context).textTheme.headlineMedium,
	),
	],
	),
	),
	floatingActionButton: FloatingActionButton(
	onPressed: _incrementCounter,
	tooltip: 'Increment',
	child: const Icon(Icons.add),
	),
	);
	}
	}
	''';

	// From https://gist.github.com/RedBrogdon/e0a2e942e85fde2cd39b2741ff0c49e5
	const sampleCodeFlutterSunflower = r'''
	import 'dart:math' as math;
	import 'package:flutter/material.dart';

	const Color primaryColor = Colors.orange;
	const TargetPlatform platform = TargetPlatform.android;

	void main() {
	runApp(Sunflower());
	}

	class SunflowerPainter extends CustomPainter {
	static const seedRadius = 2.0;
	static const scaleFactor = 4;
	static const tau = math.pi * 2;

	static final phi = (math.sqrt(5) + 1) / 2;

	final int seeds;

	SunflowerPainter(this.seeds);

	@override
	void paint(Canvas canvas, Size size) {
	final center = size.width / 2;

	for (var i = 0; i < seeds; i++) {
	final theta = i * tau / phi;
	final r = math.sqrt(i) * scaleFactor;
	final x = center + r * math.cos(theta);
	final y = center - r * math.sin(theta);
	final offset = Offset(x, y);
	if (!size.contains(offset)) {
	continue;
	}
	drawSeed(canvas, x, y);
	}
	}

	@override
	bool shouldRepaint(SunflowerPainter oldDelegate) {
	return oldDelegate.seeds != seeds;
	}

	// Draw a small circle representing a seed centered at (x,y).
	void drawSeed(Canvas canvas, double x, double y) {
	final paint = Paint()
	..strokeWidth = 2
	..style = PaintingStyle.fill
	..color = primaryColor;
	canvas.drawCircle(Offset(x, y), seedRadius, paint);
	}
	}

	class Sunflower extends StatefulWidget {
	@override
	State<Sunflower> createState() {
	return _SunflowerState();
	}
	}

	class _SunflowerState extends State<Sunflower> {
	double seeds = 100.0;

	int get seedCount => seeds.floor();

	@override
	Widget build(BuildContext context) {
	return MaterialApp(
	debugShowCheckedModeBanner: false,
	theme: ThemeData().copyWith(
	platform: platform,
	brightness: Brightness.dark,
	sliderTheme: SliderThemeData.fromPrimaryColors(
	primaryColor: primaryColor,
	primaryColorLight: primaryColor,
	primaryColorDark: primaryColor,
	valueIndicatorTextStyle: const DefaultTextStyle.fallback().style,
	),
	),
	home: Scaffold(
	appBar: AppBar(title: const Text("Sunflower")),
	drawer: Drawer(
	child: ListView(
	children: const [
	DrawerHeader(
	child: Center(
	child: Text(
	"Sunflower 🌻",
	style: TextStyle(fontSize: 32),
	),
	),
	),
	],
	)),
	body: Container(
	constraints: const BoxConstraints.expand(),
	decoration:
	BoxDecoration(border: Border.all(color: Colors.transparent)),
	child: Column(
	crossAxisAlignment: CrossAxisAlignment.center,
	mainAxisAlignment: MainAxisAlignment.start,
	children: [
	Container(
	decoration: BoxDecoration(
	border: Border.all(color: Colors.transparent)),
	child: SizedBox(
	width: 400,
	height: 400,
	child: CustomPaint(
	painter: SunflowerPainter(seedCount),
	),
	),
	),
	Text("Showing $seedCount seeds"),
	ConstrainedBox(
	constraints: const BoxConstraints.tightFor(width: 300),
	child: Slider.adaptive(
	min: 20,
	max: 2000,
	value: seeds,
	onChanged: (newValue) {
	setState(() {
	seeds = newValue;
	});
	},
	),
	),
	],
	),
	),
	),
	);
	}
	}
	''';

	// https://gist.github.com/johnpryan/5e28c5273c2c1a41d30bad9f9d11da56
	const sampleCodeFlutterDraggableCard = '''
	import 'package:flutter/material.dart';
	import 'package:flutter/physics.dart';

	main() {
	runApp(
	MaterialApp(
	debugShowCheckedModeBanner: false,
	home: PhysicsCardDragDemo(),
	),
	);
	}

	class PhysicsCardDragDemo extends StatelessWidget {
	@override
	Widget build(BuildContext context) {
	return Scaffold(
	appBar: AppBar(
	title: const Text('A draggable card!'),
	),
	body: const DraggableCard(
	child: FlutterLogo(
	size: 128,
	),
	),
	);
	}
	}

	class DraggableCard extends StatefulWidget {
	final Widget child;
	const DraggableCard({required this.child});

	@override
	State<DraggableCard> createState() => _DraggableCardState();
	}

	class _DraggableCardState extends State<DraggableCard>
	with SingleTickerProviderStateMixin {
	AnimationController? _controller;
	Alignment _dragAlignment = Alignment.center;
	Animation<Alignment>? _animation;

	void _runAnimation(Offset pixelsPerSecond, Size size) {
	_animation = _controller!.drive(
	AlignmentTween(
	begin: _dragAlignment,
	end: Alignment.center,
	),
	);

	final unitsPerSecondX = pixelsPerSecond.dx / size.width;
	final unitsPerSecondY = pixelsPerSecond.dy / size.height;
	final unitsPerSecond = Offset(unitsPerSecondX, unitsPerSecondY);
	final unitVelocity = unitsPerSecond.distance;

	const spring = SpringDescription(
	mass: 30,
	stiffness: 1,
	damping: 1,
	);

	final simulation = SpringSimulation(spring, 0, 1, -unitVelocity);

	_controller!.animateWith(simulation);
	}

	@override
	void initState() {
	super.initState();
	_controller = AnimationController(vsync: this);

	_controller!.addListener(() {
	setState(() {
	_dragAlignment = _animation!.value;
	});
	});
	}

	@override
	void dispose() {
	_controller!.dispose();
	super.dispose();
	}

	@override
	Widget build(BuildContext context) {
	final size = MediaQuery.of(context).size;
	return GestureDetector(
	onPanDown: (details) {
	_controller!.stop();
	},
	onPanUpdate: (details) {
	setState(() {
	_dragAlignment += Alignment(
	details.delta.dx / (size.width / 2),
	details.delta.dy / (size.height / 2),
	);
	});
	},
	onPanEnd: (details) {
	_runAnimation(details.velocity.pixelsPerSecond, size);
	},
	child: Align(
	alignment: _dragAlignment,
	child: Card(
	child: widget.child,
	),
	),
	);
	}
	}
	''';

	// From https://gist.github.com/johnpryan/289ecf8480ad005f01faeace70bd529a
	const sampleCodeFlutterImplicitAnimations = '''
	import 'dart:math';
	import 'package:flutter/material.dart';

	class DiscData {
	static final _rng = Random();

	final double size;
	final Color color;
	final Alignment alignment;

	DiscData()
	: size = _rng.nextDouble() * 40 + 10,
	color = Color.fromARGB(
	_rng.nextInt(200),
	_rng.nextInt(255),
	_rng.nextInt(255),
	_rng.nextInt(255),
	),
	alignment = Alignment(
	_rng.nextDouble() * 2 - 1,
	_rng.nextDouble() * 2 - 1,
	);
	}

	void main() async {
	runApp(
	MaterialApp(
	debugShowCheckedModeBanner: false,
	home: Scaffold(
	body: Container(
	color: const Color(0xFF15202D),
	child: const SizedBox.expand(
	child: VariousDiscs(50),
	),
	),
	),
	),
	);
	}

	class VariousDiscs extends StatefulWidget {
	final int numberOfDiscs;

	const VariousDiscs(this.numberOfDiscs);

	@override
	State<VariousDiscs> createState() => _VariousDiscsState();
	}

	class _VariousDiscsState extends State<VariousDiscs> {
	final _discs = <DiscData>[];

	@override
	void initState() {
	super.initState();
	_makeDiscs();
	}

	void _makeDiscs() {
	_discs.clear();
	for (int i = 0; i < widget.numberOfDiscs; i++) {
	_discs.add(DiscData());
	}
	}

	@override
	Widget build(BuildContext context) {
	return GestureDetector(
	onTap: () => setState(() {
	_makeDiscs();
	}),
	child: Stack(
	children: [
	const Center(
	child: Text(
	'Click a disc!',
	style: TextStyle(color: Colors.white, fontSize: 50),
	),
	),
	for (final disc in _discs)
	Positioned.fill(
	child: AnimatedAlign(
	duration: const Duration(milliseconds: 500),
	curve: Curves.easeInOut,
	alignment: disc.alignment,
	child: AnimatedContainer(
	duration: const Duration(milliseconds: 500),
	decoration: BoxDecoration(
	color: disc.color,
	shape: BoxShape.circle,
	),
	height: disc.size,
	width: disc.size,
	),
	),
	),
	],
	),
	);
	}
	}
	''';

	const sampleCodeMultiFoo = """
	import 'bar.dart';

	void main() {
	print(bar());
	}
	""";

	const sampleCodeMultiBar = '''
	bar() {
	return 4;
	}
	''';

	const sampleCodeLibraryMultiFoo = """
	library foofoo;

	part 'bar.dart';

	void main() {
	print(bar());
	}
	""";

	const sampleCodePartMultiBar = '''
	part of foofoo;

	bar() {
	return 4;
	}
	''';

	const sampleCodeAsync = """
	import 'dart:html';

	void main() async {
	print("hello");
	querySelector('#foo')?.text = 'bar';
	var foo = await HttpRequest.getString('http://www.google.com');
	print(foo);
	}
	""";

	const sampleCodeError = '''
	void main() {
	print("hello")
	}
	''';

	const sampleCodeErrors = '''
	void main() {
	print1("hello");
	print2("hello");
	print3("hello");
	}
	''';

	const sampleDart2Error = '''
	class Foo {
	final bool isAlwaysNull;
	Foo(this.isAlwaysNull) {}
	}

	void main(List<String> argv) {
	var x = new Foo(null);
	var y = 1;
	y = x;
	}
	''';

	/// Code fragments for testing multi file compiling.
	/// These fragments are taken from [sampleCodeFlutterImplicitAnimations] and
	/// only separated and re-arranged to facilitate testing multi file tests.

	const sampleCode3PartFlutterImplicitAnimationsImports = r'''
	import 'dart:math';
	import 'package:flutter/material.dart';
	''';

	const sampleCode3PartFlutterImplicitAnimationsMain = r'''

	void main() async {
	runApp(
	MaterialApp(
	debugShowCheckedModeBanner: false,
	home: Scaffold(
	body: Container(
	color: const Color(0xFF15202D),
	child: const SizedBox.expand(
	child: VariousDiscs(50),
	),
	),
	),
	),
	);
	}
	''';

	const sampleCode3PartFlutterImplicitAnimationsDiscData = r'''

	class DiscData {
	static final _rng = Random();

	final double size;
	final Color color;
	final Alignment alignment;

	DiscData()
	: size = _rng.nextDouble() * 40 + 10,
	color = Color.fromARGB(
	_rng.nextInt(200),
	_rng.nextInt(255),
	_rng.nextInt(255),
	_rng.nextInt(255),
	),
	alignment = Alignment(
	_rng.nextDouble() * 2 - 1,
	_rng.nextDouble() * 2 - 1,
	);
	}
	''';

	const sampleCode3PartFlutterImplicitAnimationsVarious = r'''

	class VariousDiscs extends StatefulWidget {
	final int numberOfDiscs;

	const VariousDiscs(this.numberOfDiscs);

	@override
	State<VariousDiscs> createState() => _VariousDiscsState();
	}

	class _VariousDiscsState extends State<VariousDiscs> {
	final _discs = <DiscData>[];

	@override
	void initState() {
	super.initState();
	_makeDiscs();
	}

	void _makeDiscs() {
	_discs.clear();
	for (int i = 0; i < widget.numberOfDiscs; i++) {
	_discs.add(DiscData());
	}
	}

	@override
	Widget build(BuildContext context) {
	return GestureDetector(
	onTap: () => setState(() {
	_makeDiscs();
	}),
	child: Stack(
	children: [
	const Center(
	child: Text(
	'Click a disc!',
	style: TextStyle(color: Colors.white, fontSize: 50),
	),
	),
	for (final disc in _discs)
	Positioned.fill(
	child: AnimatedAlign(
	duration: const Duration(milliseconds: 500),
	curve: Curves.easeInOut,
	alignment: disc.alignment,
	child: AnimatedContainer(
	duration: const Duration(milliseconds: 500),
	decoration: BoxDecoration(
	color: disc.color,
	shape: BoxShape.circle,
	),
	height: disc.size,
	width: disc.size,
	),
	),
	),
	],
	),
	);
	}
	}
	''';

	/// Create 2 files for multi file testing using imports.
	const sampleCode2PartImportMain = '''
	$sampleCode3PartFlutterImplicitAnimationsImports
	import 'various.dart';
	$sampleCode3PartFlutterImplicitAnimationsMain
	''';

	const sampleCode2PartImportVarious = '''
	$sampleCode3PartFlutterImplicitAnimationsImports
	$sampleCode3PartFlutterImplicitAnimationsDiscData
	$sampleCode3PartFlutterImplicitAnimationsVarious
	''';

	/// Create 3 separate files for multi file testing using imports.
	/// Here main.dart will be importing 'various.dart' and 'discdata.dart',
	/// and 'various.dart' importing 'discdata.dart'.
	const sampleCode3PartImportMain = '''
	$sampleCode3PartFlutterImplicitAnimationsImports
	import 'various.dart';
	import 'discdata.dart';
	$sampleCode3PartFlutterImplicitAnimationsMain
	''';

	const sampleCode3PartImportDiscData = '''
	$sampleCode3PartFlutterImplicitAnimationsImports
	$sampleCode3PartFlutterImplicitAnimationsDiscData
	''';

	const sampleCode3PartImportVarious = '''
	$sampleCode3PartFlutterImplicitAnimationsImports
	import 'discdata.dart';
	$sampleCode3PartFlutterImplicitAnimationsVarious
	''';

	/// Create 2 file test using "part 'various.dart'" to bring in second file.
	const sampleCode2PartLibraryMain = '''
	library testanim;
	$sampleCode3PartFlutterImplicitAnimationsImports
	part 'various.dart';
	$sampleCode3PartFlutterImplicitAnimationsMain
	''';

	const sampleCode2PartVariousAndDiscDataPartOfTestAnim = '''
	part of testanim;
	$sampleCode3PartFlutterImplicitAnimationsDiscData
	$sampleCode3PartFlutterImplicitAnimationsVarious
	''';

	/// Create 3 file test using "part 'various.dart'" and "part 'discdata.dart'"
	/// to bring in second and third files.
	const sampleCode3PartLibraryMain = '''
	library testanim;
	$sampleCode3PartFlutterImplicitAnimationsImports
	part 'discdata.dart';
	part 'various.dart';
	$sampleCode3PartFlutterImplicitAnimationsMain
	''';

	const sampleCode3PartDiscDataPartOfTestAnim = '''
	part of testanim;
	$sampleCode3PartFlutterImplicitAnimationsDiscData
	''';

	const sampleCode3PartVariousPartOfTestAnim = '''
	part of testanim;
	$sampleCode3PartFlutterImplicitAnimationsVarious
	''';

	class Lines {
	final List<int> _starts = <int>[];

	Lines(String source) {
	final units = source.codeUnits;
	for (var i = 0; i < units.length; i++) {
	if (units[i] == 10) _starts.add(i);
	}
	}

	/// Return the 0-based line number.
	int getLineForOffset(int offset) {
	for (var i = 0; i < _starts.length; i++) {
	if (offset <= _starts[i]) return i;
	}
	return _starts.length;
	}
	}

	/// Returns the version of the current Dart runtime.
	///
	/// The returned `String` is formatted as the [semver](http://semver.org) version
	/// string of the current Dart runtime, possibly followed by whitespace and other
	/// version and build details.
	String get vmVersion => Platform.version;

	/// If [str] has leading and trailing quotes, remove them.
	String stripMatchingQuotes(String str) {
	if (str.length <= 1) return str;

	if (str.startsWith("'") && str.endsWith("'")) {
	str = str.substring(1, str.length - 1);
	} else if (str.startsWith('"') && str.endsWith('"')) {
	str = str.substring(1, str.length - 1);
	}
	return str;
	}

	class _SourcesGroupFile {
	String filename;
	String content;

	_SourcesGroupFile(this.filename, this.content);
	}

	///This RegExp matches a variety of possible `main` function definition formats
	///Like:
	/// - `Future<void> main(List<String> args) async {`
	/// - `void main(List<String> args) async {`
	/// - `void main() {`
	/// - `void main( List < String > args ) async {`
	/// - `void main(Args arg) {`
	/// - `main() {`
	/// - `void main() {}`
	/// - `void main() => runApp(MyApp());`
	final RegExp mainFunctionDefinition = RegExp(
	r'''[\s](Future)?[\<]?(void)?[\>]?[\s]main[\s]\((\s\w\s\<?\s\w\s\>?\s\w\s)?\)\s(async)?\s[\{\|\=]+''');

	/// Used to remove 2 or more '..' and any number of following slashes of '/' or '\'.
	final RegExp sanitizeUpDirectories = RegExp(r'[\.]{2,}[\\\/]*');

	/// Used to remove 'package:', 'dart:', 'http://', 'https://' etc.
	final RegExp sanitizePackageDartHttp = RegExp(r'[\w][\:][\/]');

	/// Sanitizes [filename] by using the regular expressions
	/// [sanitizeUpDirectories] and [sanitizePackageDartHttp] to remove
	/// anything like 'package:', 'dart:' or 'http://', and then removing
	/// runs of more than a single '.' (do not allow '..' up directories to
	/// escape temp directory).
	String _sanitizeFileName(String filename) {
	filename = filename.replaceAll(sanitizePackageDartHttp, '');
	filename = filename.replaceAll(sanitizeUpDirectories, '');
	return filename;
	}

	/// Goes through [sources] map of source files and sanitizes the filenames
	/// and ensures that the file containing the main entry point that bootstrap
	/// will be calling is called [kMainDart].
	/// [sources] is a map containing the source files in the format
	/// `{ "filename1":"sourcecode1" .. "filenameN":"sourcecodeN"}`.
	/// [activeSourceName] is the name of the source file active in the editor.
	/// Returns [activeSourceName] or a new name if sanitized or renamed.
	String sanitizeAndCheckFilenames(Map<String, String> sources,
	[String activeSourceName = kMainDart]) {
	activeSourceName = _sanitizeFileName(activeSourceName);

	final files =
	sources.entries.map((e) => _SourcesGroupFile(e.key, e.value)).toList();

	var foundKMain = false;
	// Check for kMainDart file and also sanitize filenames.
	for (final sourceFile in files) {
	sourceFile.filename = _sanitizeFileName(sourceFile.filename);
	if (sourceFile.filename == kMainDart) {
	foundKMain = true;
	}
	}
	// One of the files must be named kMainDart. This is the file that the
	// bootstrap dart file will import and call main() on.
	if (!foundKMain && files.isNotEmpty) {
	// We need to rename the file containing the main() function to kMainDart.
	for (final sourceFile in files) {
	if (mainFunctionDefinition.hasMatch(sourceFile.content)) {
	// This file has a main() function, rename it to kMainDart
	// and also change activeSourceName if that is the file being
	// renamed.
	if (sourceFile.filename == activeSourceName) {
	activeSourceName = kMainDart;
	}
	sourceFile.filename = kMainDart;
	foundKMain = true;
	break;
	}
	}
	if (!foundKMain) {
	// No kMainDart was found so just change the first file to be kMainDart.
	if (files[0].filename == activeSourceName) {
	activeSourceName = kMainDart;
	}
	files[0].filename = kMainDart;
	}
	}

	// Take our files list and create a new files {filename:content} map.
	sources.clear();
	for (final sourceFiles in files) {
	sources[sourceFiles.filename] = sourceFiles.content;
	}

	return activeSourceName;
	}

	/// Count the total lines across all files in [sources] file map.
	int countLines(Map<String, String> sources) {
	var totalLines = 0;
	for (final filename in sources.keys) {
	totalLines += countLinesInString(sources[filename]!);
	}
	return totalLines;
	}

	// Character constants.
	const int _lf = 10;
	const int _cr = 13;

	/// Count lines in string (CR, LF or CR-LF can be line separators).
	/// (Gives correct result as opposed to .split('\n').length, which
	/// reports 1 extra line in many cases, and this does so without the
	/// extra work .split() would do by creating the list of copied strings).
	int countLinesInString(String str) {
	final data = str.codeUnits;
	var lines = 0;
	final end = data.length;
	var sliceStart = 0;
	var char = 0;
	for (var i = 0; i < end; i++) {
	final previousChar = char;
	char = data[i];
	if (char != _cr) {
	if (char != _lf) continue;
	if (previousChar == _cr) {
	sliceStart = i + 1;
	continue;
	}
	}
	lines++;
	sliceStart = i + 1;
	}
	if (sliceStart < end) {
	lines++;
	}
	return lines;
	}