[engine, web] return switch expressions in many places (#162336)

engine/src/flutter/lib/web_ui/dev/common.dart

@@ -269,14 +269,10 @@ const List<String> kAllBrowserNames = <String>[kChrome, kEdge, kFirefox, kSafari
 ///
 /// The [browserName] matches the browser name passed as the `--browser` option.
 BrowserEnvironment getBrowserEnvironment(BrowserName browserName, {required bool useDwarf}) {
-  switch (browserName) {
+  return switch (browserName) {
-    case BrowserName.chrome:
+    BrowserName.chrome => ChromeEnvironment(useDwarf: useDwarf),
-      return ChromeEnvironment(useDwarf: useDwarf);
+    BrowserName.edge => EdgeEnvironment(),
-    case BrowserName.edge:
+    BrowserName.firefox => FirefoxEnvironment(),
-      return EdgeEnvironment();
+    BrowserName.safari => SafariMacOsEnvironment(),
-    case BrowserName.firefox:
+  };
-      return FirefoxEnvironment();
-    case BrowserName.safari:
-      return SafariMacOsEnvironment();
-  }
 }

engine/src/flutter/lib/web_ui/dev/steps/compile_bundle_step.dart

@@ -64,22 +64,20 @@ class CompileBundleStep implements PipelineStep {
   }
 
   TestCompiler _createCompiler(CompileConfiguration config) {
-    switch (config.compiler) {
+    return switch (config.compiler) {
-      case Compiler.dart2js:
+      Compiler.dart2js => Dart2JSCompiler(
-        return Dart2JSCompiler(
         testSetDirectory,
         outputBundleDirectory,
         renderer: config.renderer,
         isVerbose: isVerbose,
-        );
+      ),
-      case Compiler.dart2wasm:
+      Compiler.dart2wasm => Dart2WasmCompiler(
-        return Dart2WasmCompiler(
         testSetDirectory,
         outputBundleDirectory,
         renderer: config.renderer,
         isVerbose: isVerbose,
-        );
+      ),
-    }
+    };
   }
 
   @override

engine/src/flutter/lib/web_ui/dev/test_platform.dart

@@ -477,14 +477,11 @@ class BrowserPlatform extends PlatformPlugin {
   }
 
   String getCanvasKitVariant() {
-    switch (suite.runConfig.variant) {
+    return switch (suite.runConfig.variant) {
-      case CanvasKitVariant.full:
+      CanvasKitVariant.full => 'full',
-        return 'full';
+      CanvasKitVariant.chromium => 'chromium',
-      case CanvasKitVariant.chromium:
+      null => 'auto',
-        return 'chromium';
+    };
-      case null:
-        return 'auto';
-    }
   }
 
   String _makeBuildConfigString(String scriptBase, CompileConfiguration config) {

engine/src/flutter/lib/web_ui/lib/key.dart

@@ -133,55 +133,33 @@ class KeyData {
     // JavaScript only support 32-bit bitwise operations and needs to use
     // division instead.
     final int planeNum = (logical / 0x100000000).floor();
-    final String planeDescription =
+    final String planeDescription = switch (planeNum) {
-        (() {
+      0x000 => ' (Unicode)',
-          switch (planeNum) {
+      0x001 => ' (Unprintable)',
-            case 0x000:
+      0x002 => ' (Flutter)',
-              return ' (Unicode)';
+      0x011 => ' (Android)',
-            case 0x001:
+      0x012 => ' (Fuchsia)',
-              return ' (Unprintable)';
+      0x013 => ' (iOS)',
-            case 0x002:
+      0x014 => ' (macOS)',
-              return ' (Flutter)';
+      0x015 => ' (GTK)',
-            case 0x011:
+      0x016 => ' (Windows)',
-              return ' (Android)';
+      0x017 => ' (Web)',
-            case 0x012:
+      0x018 => ' (GLFW)',
-              return ' (Fuchsia)';
+      _ => '',
-            case 0x013:
+    };
-              return ' (iOS)';
-            case 0x014:
-              return ' (macOS)';
-            case 0x015:
-              return ' (GTK)';
-            case 0x016:
-              return ' (Windows)';
-            case 0x017:
-              return ' (Web)';
-            case 0x018:
-              return ' (GLFW)';
-          }
-          return '';
-        })();
     return '$result$planeDescription';
   }
 
   String? _escapeCharacter() {
-    if (character == null) {
+    return switch (character) {
-      return '<none>';
+      null => '<none>',
-    }
+      '\n' => r'"\n"',
-    switch (character!) {
+      '\t' => r'"\t"',
-      case '\n':
+      '\r' => r'"\r"',
-        return r'"\n"';
+      '\b' => r'"\b"',
-      case '\t':
+      '\f' => r'"\f"',
-        return r'"\t"';
+      _ => '"$character"',
-      case '\r':
+    };
-        return r'"\r"';
-      case '\b':
-        return r'"\b"';
-      case '\f':
-        return r'"\f"';
-      default:
-        return '"$character"';
-    }
   }
 
   String? _quotedCharCode() {

engine/src/flutter/lib/web_ui/lib/painting.dart

@@ -705,15 +705,12 @@ Future<void> _decodeImageFromListAsync(Uint8List list, ImageDecoderCallback call
 // to right, then from top to down. The order of the 4 bytes of pixels is
 // decided by `format`.
 Future<Codec> createBmp(Uint8List pixels, int width, int height, int rowBytes, PixelFormat format) {
-  late bool swapRedBlue;
+  final bool swapRedBlue = switch (format) {
-  switch (format) {
+    PixelFormat.bgra8888 => true,
-    case PixelFormat.bgra8888:
+    PixelFormat.rgba8888 => false,
-      swapRedBlue = true;
+    PixelFormat.rgbaFloat32 =>
-    case PixelFormat.rgba8888:
+      throw UnimplementedError('RGB conversion from rgbaFloat32 data is not implemented'),
-      swapRedBlue = false;
+  };
-    case PixelFormat.rgbaFloat32:
-      throw UnimplementedError('RGB conversion from rgbaFloat32 data is not implemented');
-  }
 
   // See https://en.wikipedia.org/wiki/BMP_file_format for format examples.
   // The header is in the 108-byte BITMAPV4HEADER format, or as called by

engine/src/flutter/lib/web_ui/lib/src/engine/canvas_pool.dart

@@ -911,7 +911,7 @@ class ContextStateHandle {
     strokeCap ??= ui.StrokeCap.butt;
     if (strokeCap != _currentStrokeCap) {
       _currentStrokeCap = strokeCap;
-      context.lineCap = stringForStrokeCap(strokeCap)!;
+      context.lineCap = strokeCap.name;
     }
   }
 
@@ -928,7 +928,7 @@ class ContextStateHandle {
     strokeJoin ??= ui.StrokeJoin.miter;
     if (strokeJoin != _currentStrokeJoin) {
       _currentStrokeJoin = strokeJoin;
-      context.lineJoin = stringForStrokeJoin(strokeJoin);
+      context.lineJoin = strokeJoin.name;
     }
   }
 

engine/src/flutter/lib/web_ui/lib/src/engine/canvaskit/canvaskit_api.dart

@@ -3431,17 +3431,14 @@ String get _canvasKitBaseUrl => configuration.canvasKitBaseUrl;
 
 @visibleForTesting
 List<String> getCanvasKitJsFileNames(CanvasKitVariant variant) {
-  switch (variant) {
+  return switch (variant) {
-    case CanvasKitVariant.auto:
+    CanvasKitVariant.auto => <String>[
-      return <String>[
       if (_enableCanvasKitChromiumInAutoMode) _kChromiumCanvasKitJsFileName,
       _kFullCanvasKitJsFileName,
-      ];
+    ],
-    case CanvasKitVariant.full:
+    CanvasKitVariant.full => <String>[_kFullCanvasKitJsFileName],
-      return <String>[_kFullCanvasKitJsFileName];
+    CanvasKitVariant.chromium => <String>[_kChromiumCanvasKitJsFileName],
-    case CanvasKitVariant.chromium:
+  };
-      return <String>[_kChromiumCanvasKitJsFileName];
-  }
 }
 
 Iterable<String> get _canvasKitJsUrls {

engine/src/flutter/lib/web_ui/lib/src/engine/canvaskit/embedded_views.dart

@@ -614,12 +614,10 @@ class HtmlViewEmbedder {
   }
 
   DomElement _getElement(RenderingEntity entity) {
-    switch (entity) {
+    return switch (entity) {
-      case RenderingRenderCanvas():
+      RenderingRenderCanvas() => entity.displayCanvas!.hostElement,
-        return entity.displayCanvas!.hostElement;
+      RenderingPlatformView() => _viewClipChains[entity.viewId]!.root,
-      case RenderingPlatformView():
+    };
-        return _viewClipChains[entity.viewId]!.root;
-    }
   }
 
   /// Returns a [List] of ints mapping elements from the [next] rendering to
@@ -796,18 +794,13 @@ class Mutator {
       return false;
     }
 
-    switch (type) {
+    return switch (type) {
-      case MutatorType.clipRect:
+      MutatorType.clipRect => rect == typedOther.rect,
-        return rect == typedOther.rect;
+      MutatorType.clipRRect => rrect == typedOther.rrect,
-      case MutatorType.clipRRect:
+      MutatorType.clipPath => path == typedOther.path,
-        return rrect == typedOther.rrect;
+      MutatorType.transform => matrix == typedOther.matrix,
-      case MutatorType.clipPath:
+      MutatorType.opacity => alpha == typedOther.alpha,
-        return path == typedOther.path;
+    };
-      case MutatorType.transform:
-        return matrix == typedOther.matrix;
-      case MutatorType.opacity:
-        return alpha == typedOther.alpha;
-    }
   }
 
   @override

engine/src/flutter/lib/web_ui/lib/src/engine/canvaskit/text.dart

@@ -899,13 +899,10 @@ class CkParagraph implements ui.Paragraph {
   @override
   ui.TextRange getWordBoundary(ui.TextPosition position) {
     assert(!_disposed, 'Paragraph has been disposed.');
-    final int characterPosition;
+    final int characterPosition = switch (position.affinity) {
-    switch (position.affinity) {
+      ui.TextAffinity.upstream => position.offset - 1,
-      case ui.TextAffinity.upstream:
+      ui.TextAffinity.downstream => position.offset,
-        characterPosition = position.offset - 1;
+    };
-      case ui.TextAffinity.downstream:
-        characterPosition = position.offset;
-    }
     final SkTextRange skRange = skiaObject.getWordBoundary(characterPosition.toDouble());
     return ui.TextRange(start: skRange.start.toInt(), end: skRange.end.toInt());
   }

engine/src/flutter/lib/web_ui/lib/src/engine/html/bitmap_canvas.dart

@@ -1323,31 +1323,6 @@ SvgBlendMode? blendModeToSvgEnum(ui.BlendMode? blendMode) {
   }
 }
 
-String? stringForStrokeCap(ui.StrokeCap? strokeCap) {
-  if (strokeCap == null) {
-    return null;
-  }
-  switch (strokeCap) {
-    case ui.StrokeCap.butt:
-      return 'butt';
-    case ui.StrokeCap.round:
-      return 'round';
-    case ui.StrokeCap.square:
-      return 'square';
-  }
-}
-
-String stringForStrokeJoin(ui.StrokeJoin strokeJoin) {
-  switch (strokeJoin) {
-    case ui.StrokeJoin.round:
-      return 'round';
-    case ui.StrokeJoin.bevel:
-      return 'bevel';
-    case ui.StrokeJoin.miter:
-      return 'miter';
-  }
-}
-
 /// Clips the content element against a stack of clip operations and returns
 /// root of a tree that contains content node.
 ///

engine/src/flutter/lib/web_ui/lib/src/engine/html/dom_canvas.dart

@@ -14,7 +14,6 @@ import '../svg.dart';
 import '../text/canvas_paragraph.dart';
 import '../util.dart';
 import '../vector_math.dart';
-import 'bitmap_canvas.dart';
 import 'painting.dart';
 import 'path/path.dart';
 import 'path/path_to_svg.dart';
@@ -351,8 +350,8 @@ SVGSVGElement pathToSvgElement(SurfacePath path, SurfacePaintData paint) {
           paint.strokeWidth != null)) {
     svgPath.setAttribute('stroke', colorValueToCssString(paint.color));
     svgPath.setAttribute('stroke-width', '${paint.strokeWidth ?? 1.0}');
-    if (paint.strokeCap != null) {
+    if (paint.strokeCap case final value?) {
-      svgPath.setAttribute('stroke-linecap', '${stringForStrokeCap(paint.strokeCap)}');
+      svgPath.setAttribute('stroke-linecap', value.name);
     }
     svgPath.setAttribute('fill', 'none');
   } else {

engine/src/flutter/lib/web_ui/lib/src/engine/services/message_codecs.dart

@@ -453,14 +453,11 @@ class StandardMessageCodec implements MessageCodec<dynamic> {
   /// [readValueOfType].
   int readSize(ReadBuffer buffer) {
     final int value = buffer.getUint8();
-    switch (value) {
+    return switch (value) {
-      case 254:
+      254 => buffer.getUint16(),
-        return buffer.getUint16();
+      255 => buffer.getUint32(),
-      case 255:
+      _ => value,
-        return buffer.getUint32();
+    };
-      default:
-        return value;
-    }
   }
 }
 

engine/src/flutter/lib/web_ui/lib/src/engine/shader_data.dart

@@ -118,33 +118,20 @@ enum UniformType {
 }
 
 UniformType? uniformTypeFromJson(int value) {
-  switch (value) {
+  return switch (value) {
-    case 0:
+    0 => UniformType.Boolean,
-      return UniformType.Boolean;
+    1 => UniformType.SByte,
-    case 1:
+    2 => UniformType.UByte,
-      return UniformType.SByte;
+    3 => UniformType.Short,
-    case 2:
+    4 => UniformType.UShort,
-      return UniformType.UByte;
+    5 => UniformType.Int,
-    case 3:
+    6 => UniformType.Uint,
-      return UniformType.Short;
+    7 => UniformType.Int64,
-    case 4:
+    8 => UniformType.Uint64,
-      return UniformType.UShort;
+    9 => UniformType.Half,
-    case 5:
+    10 => UniformType.Float,
-      return UniformType.Int;
+    11 => UniformType.Double,
-    case 6:
+    12 => UniformType.SampledImage,
-      return UniformType.Uint;
+    _ => null,
-    case 7:
+  };
-      return UniformType.Int64;
-    case 8:
-      return UniformType.Uint64;
-    case 9:
-      return UniformType.Half;
-    case 10:
-      return UniformType.Float;
-    case 11:
-      return UniformType.Double;
-    case 12:
-      return UniformType.SampledImage;
-  }
-  return null;
 }

engine/src/flutter/lib/web_ui/lib/src/engine/text/canvas_paragraph.dart

@@ -225,13 +225,10 @@ class CanvasParagraph implements ui.Paragraph {
 
   @override
   ui.TextRange getWordBoundary(ui.TextPosition position) {
-    final int characterPosition;
+    final int characterPosition = switch (position.affinity) {
-    switch (position.affinity) {
+      ui.TextAffinity.upstream => position.offset - 1,
-      case ui.TextAffinity.upstream:
+      ui.TextAffinity.downstream => position.offset,
-        characterPosition = position.offset - 1;
+    };
-      case ui.TextAffinity.downstream:
-        characterPosition = position.offset;
-    }
     final int start = WordBreaker.prevBreakIndex(plainText, characterPosition + 1);
     final int end = WordBreaker.nextBreakIndex(plainText, characterPosition);
     return ui.TextRange(start: start, end: end);

engine/src/flutter/lib/web_ui/lib/src/engine/text/layout_service.dart

@@ -587,18 +587,13 @@ class LineBuilder {
     final double emptySpace = maxWidth - width;
     final ui.TextAlign textAlign = paragraph.paragraphStyle.effectiveTextAlign;
 
-    switch (textAlign) {
+    return switch (textAlign) {
-      case ui.TextAlign.center:
+      ui.TextAlign.center => emptySpace / 2.0,
-        return emptySpace / 2.0;
+      ui.TextAlign.right => emptySpace,
-      case ui.TextAlign.right:
+      ui.TextAlign.start => _paragraphDirection == ui.TextDirection.rtl ? emptySpace : 0.0,
-        return emptySpace;
+      ui.TextAlign.end => _paragraphDirection == ui.TextDirection.rtl ? 0.0 : emptySpace,
-      case ui.TextAlign.start:
+      _ => 0.0,
-        return _paragraphDirection == ui.TextDirection.rtl ? emptySpace : 0.0;
+    };
-      case ui.TextAlign.end:
-        return _paragraphDirection == ui.TextDirection.rtl ? 0.0 : emptySpace;
-      default:
-        return 0.0;
-    }
   }
 
   bool get isOverflowing => width > maxWidth;

engine/src/flutter/lib/web_ui/lib/src/engine/text/paragraph.dart

@@ -1108,26 +1108,11 @@ String? _textDecorationToCssString(
     }
   }
   if (decorationStyle != null) {
-    decorations.write(_decorationStyleToCssString(decorationStyle));
+    decorations.write(decorationStyle.name);
   }
   return decorations.isEmpty ? null : decorations.toString();
 }
 
-String? _decorationStyleToCssString(ui.TextDecorationStyle decorationStyle) {
-  switch (decorationStyle) {
-    case ui.TextDecorationStyle.dashed:
-      return 'dashed';
-    case ui.TextDecorationStyle.dotted:
-      return 'dotted';
-    case ui.TextDecorationStyle.double:
-      return 'double';
-    case ui.TextDecorationStyle.solid:
-      return 'solid';
-    case ui.TextDecorationStyle.wavy:
-      return 'wavy';
-  }
-}
-
 /// Converts [align] to its corresponding CSS value.
 ///
 /// This value is used as the "text-align" CSS property, e.g.:

engine/src/flutter/lib/web_ui/lib/src/engine/text/text_direction.dart

@@ -166,16 +166,11 @@ FragmentFlow _getFragmentFlow(String text, int i) {
   }
 
   final ui.TextDirection? textDirection = _textDirectionLookup.findForChar(codePoint);
-  switch (textDirection) {
+  return switch (textDirection) {
-    case ui.TextDirection.ltr:
+    ui.TextDirection.ltr => FragmentFlow.ltr,
-      return FragmentFlow.ltr;
+    ui.TextDirection.rtl => FragmentFlow.rtl,
-
+    null => FragmentFlow.sandwich,
-    case ui.TextDirection.rtl:
+  };
-      return FragmentFlow.rtl;
-
-    case null:
-      return FragmentFlow.sandwich;
-  }
 }
 
 bool _isDigit(int codePoint) {

engine/src/flutter/lib/web_ui/lib/src/engine/util.dart

@@ -345,20 +345,14 @@ String colorValueToCssString(int value) {
   if ((0xff000000 & value) == 0xff000000) {
     final String hexValue = (value & 0xFFFFFF).toRadixString(16);
     final int hexValueLength = hexValue.length;
-    switch (hexValueLength) {
+    return switch (hexValueLength) {
-      case 1:
+      1 => '#00000$hexValue',
-        return '#00000$hexValue';
+      2 => '#0000$hexValue',
-      case 2:
+      3 => '#000$hexValue',
-        return '#0000$hexValue';
+      4 => '#00$hexValue',
-      case 3:
+      5 => '#0$hexValue',
-        return '#000$hexValue';
+      _ => '#$hexValue',
-      case 4:
+    };
-        return '#00$hexValue';
-      case 5:
-        return '#0$hexValue';
-      default:
-        return '#$hexValue';
-    }
   } else {
     final double alpha = ((value >> 24) & 0xFF) / 255.0;
     final StringBuffer sb = StringBuffer();
@@ -889,20 +883,7 @@ class LruCache<K extends Object, V extends Object> {
 }
 
 /// Returns the VM-compatible string for the tile mode.
-String tileModeString(ui.TileMode? tileMode) {
+String tileModeString(ui.TileMode? tileMode) => tileMode?.name ?? 'unspecified';
-  switch (tileMode) {
-    case ui.TileMode.clamp:
-      return 'clamp';
-    case ui.TileMode.mirror:
-      return 'mirror';
-    case ui.TileMode.repeated:
-      return 'repeated';
-    case ui.TileMode.decal:
-      return 'decal';
-    case null:
-      return 'unspecified';
-  }
-}
 
 /// A size where both the width and height are integers.
 class BitmapSize {