diff --git a/packages/pigeon/CHANGELOG.md b/packages/pigeon/CHANGELOG.md
index e286a9c297a..2af203239b6 100644
--- a/packages/pigeon/CHANGELOG.md
+++ b/packages/pigeon/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 5.0.0
+
+* Creates new Generator classes for each language.
+
 ## 4.2.16
 
 * [swift] Fixes warnings with `Object` parameters.
diff --git a/packages/pigeon/lib/cpp_generator.dart b/packages/pigeon/lib/cpp_generator.dart
index 7e66600fa49..cddefacfc79 100644
--- a/packages/pigeon/lib/cpp_generator.dart
+++ b/packages/pigeon/lib/cpp_generator.dart
@@ -4,6 +4,7 @@
 
 import 'ast.dart';
 import 'functional.dart';
+import 'generator.dart';
 import 'generator_tools.dart';
 import 'pigeon_lib.dart' show Error;
 
@@ -21,14 +22,15 @@ const String _defaultCodecSerializer = 'flutter::StandardCodecSerializer';
 class CppOptions {
   /// Creates a [CppOptions] object
   const CppOptions({
-    this.header,
+    this.headerIncludePath,
     this.namespace,
     this.copyrightHeader,
+    this.headerOutPath,
   });
 
   /// The path to the header that will get placed in the source filed (example:
   /// "foo.h").
-  final String? header;
+  final String? headerIncludePath;
 
   /// The namespace where the generated class will live.
   final String? namespace;
@@ -36,13 +38,17 @@ class CppOptions {
   /// A copyright header that will get prepended to generated code.
   final Iterable<String>? copyrightHeader;
 
+  /// The path to the output header file location.
+  final String? headerOutPath;
+
   /// Creates a [CppOptions] from a Map representation where:
   /// `x = CppOptions.fromMap(x.toMap())`.
   static CppOptions fromMap(Map<String, Object> map) {
     return CppOptions(
-      header: map['header'] as String?,
+      headerIncludePath: map['header'] as String?,
       namespace: map['namespace'] as String?,
       copyrightHeader: map['copyrightHeader'] as Iterable<String>?,
+      headerOutPath: map['cppHeaderOut'] as String?,
     );
   }
 
@@ -50,7 +56,7 @@ class CppOptions {
   /// `x = CppOptions.fromMap(x.toMap())`.
   Map<String, Object> toMap() {
     final Map<String, Object> result = <String, Object>{
-      if (header != null) 'header': header!,
+      if (headerIncludePath != null) 'header': headerIncludePath!,
       if (namespace != null) 'namespace': namespace!,
       if (copyrightHeader != null) 'copyrightHeader': copyrightHeader!,
     };
@@ -64,6 +70,25 @@ class CppOptions {
   }
 }
 
+/// Class that manages all Cpp code generation.
+class CppGenerator extends Generator<OutputFileOptions<CppOptions>> {
+  /// Instantiates a Cpp Generator.
+  CppGenerator();
+
+  /// Generates Cpp files with specified [OutputFileOptions<CppOptions>]
+  @override
+  void generate(OutputFileOptions<CppOptions> languageOptions, Root root,
+      StringSink sink) {
+    final FileType fileType = languageOptions.fileType;
+    assert(fileType == FileType.header || fileType == FileType.source);
+    if (fileType == FileType.header) {
+      generateCppHeader(languageOptions.languageOptions, root, sink);
+    } else {
+      generateCppSource(languageOptions.languageOptions, root, sink);
+    }
+  }
+}
+
 String _getCodecSerializerName(Api api) => '${api.name}CodecSerializer';
 
 const String _pointerPrefix = 'pointer';
@@ -1026,8 +1051,8 @@ void _writeSystemHeaderIncludeBlock(Indent indent, List<String> headers) {
 
 /// Generates the ".h" file for the AST represented by [root] to [sink] with the
 /// provided [options] and [headerFileName].
-void generateCppHeader(
-    String? headerFileName, CppOptions options, Root root, StringSink sink) {
+void generateCppHeader(CppOptions options, Root root, StringSink sink) {
+  final String? headerFileName = options.headerOutPath;
   final Indent indent = Indent(sink);
   if (options.copyrightHeader != null) {
     addLines(indent, options.copyrightHeader!, linePrefix: '// ');
@@ -1128,7 +1153,7 @@ void generateCppSource(CppOptions options, Root root, StringSink sink) {
   indent.addln('#undef _HAS_EXCEPTIONS');
   indent.addln('');
 
-  indent.writeln('#include "${options.header}"');
+  indent.writeln('#include "${options.headerIncludePath}"');
   indent.addln('');
   _writeSystemHeaderIncludeBlock(indent, <String>[
     'flutter/basic_message_channel.h',
diff --git a/packages/pigeon/lib/dart_generator.dart b/packages/pigeon/lib/dart_generator.dart
index 0500bd4d945..e6f685052f1 100644
--- a/packages/pigeon/lib/dart_generator.dart
+++ b/packages/pigeon/lib/dart_generator.dart
@@ -9,6 +9,7 @@ import 'package:yaml/yaml.dart' as yaml;
 
 import 'ast.dart';
 import 'functional.dart';
+import 'generator.dart';
 import 'generator_tools.dart';
 
 /// Documentation comment open symbol.
@@ -24,11 +25,21 @@ const String _standardMessageCodec = 'StandardMessageCodec';
 /// Options that control how Dart code will be generated.
 class DartOptions {
   /// Constructor for DartOptions.
-  const DartOptions({this.copyrightHeader});
+  DartOptions({
+    this.copyrightHeader,
+    this.sourceOutPath,
+    this.testOutPath,
+  });
 
   /// A copyright header that will get prepended to generated code.
   final Iterable<String>? copyrightHeader;
 
+  /// Path to output generated Dart file.
+  String? sourceOutPath;
+
+  /// Path to output generated Test file for tests.
+  String? testOutPath;
+
   /// Creates a [DartOptions] from a Map representation where:
   /// `x = DartOptions.fromMap(x.toMap())`.
   static DartOptions fromMap(Map<String, Object> map) {
@@ -36,6 +47,8 @@ class DartOptions {
         map['copyrightHeader'] as Iterable<dynamic>?;
     return DartOptions(
       copyrightHeader: copyrightHeader?.cast<String>(),
+      sourceOutPath: map['sourceOutPath'] as String?,
+      testOutPath: map['testOutPath'] as String?,
     );
   }
 
@@ -44,6 +57,8 @@ class DartOptions {
   Map<String, Object> toMap() {
     final Map<String, Object> result = <String, Object>{
       if (copyrightHeader != null) 'copyrightHeader': copyrightHeader!,
+      if (sourceOutPath != null) 'sourceOutPath': sourceOutPath!,
+      if (testOutPath != null) 'testOutPath': testOutPath!,
     };
     return result;
   }
@@ -55,6 +70,33 @@ class DartOptions {
   }
 }
 
+/// Class that manages all Dart code generation.
+class DartGenerator extends Generator<DartOptions> {
+  /// Instantiates a Dart Generator.
+  DartGenerator();
+
+  /// Generates Dart files with specified [DartOptions]
+  @override
+  void generate(DartOptions languageOptions, Root root, StringSink sink,
+      {FileType fileType = FileType.na}) {
+    assert(fileType == FileType.na);
+    generateDart(languageOptions, root, sink);
+  }
+
+  /// Generates Dart files for testing with specified [DartOptions]
+  void generateTest(DartOptions languageOptions, Root root, StringSink sink) {
+    final String sourceOutPath = languageOptions.sourceOutPath ?? '';
+    final String testOutPath = languageOptions.testOutPath ?? '';
+    generateTestDart(
+      languageOptions,
+      root,
+      sink,
+      sourceOutPath: sourceOutPath,
+      testOutPath: testOutPath,
+    );
+  }
+}
+
 String _escapeForDartSingleQuotedString(String raw) {
   return raw
       .replaceAll(r'\', r'\\')
@@ -699,14 +741,14 @@ String _posixify(String inputPath) {
 }
 
 /// Generates Dart source code for test support libraries based on the given AST
-/// represented by [root], outputting the code to [sink]. [dartOutPath] is the
+/// represented by [root], outputting the code to [sink]. [sourceOutPath] is the
 /// path of the generated dart code to be tested. [testOutPath] is where the
 /// test code will be generated.
 void generateTestDart(
   DartOptions opt,
   Root root,
   StringSink sink, {
-  required String dartOutPath,
+  required String sourceOutPath,
   required String testOutPath,
 }) {
   final Indent indent = Indent(sink);
@@ -730,10 +772,10 @@ void generateTestDart(
   indent.writeln('');
   final String relativeDartPath =
       path.Context(style: path.Style.posix).relative(
-    _posixify(dartOutPath),
+    _posixify(sourceOutPath),
     from: _posixify(path.dirname(testOutPath)),
   );
-  late final String? packageName = _deducePackageName(dartOutPath);
+  late final String? packageName = _deducePackageName(sourceOutPath);
   if (!relativeDartPath.contains('/lib/') || packageName == null) {
     // If we can't figure out the package name or the relative path doesn't
     // include a 'lib' directory, try relative path import which only works in
diff --git a/packages/pigeon/lib/generator.dart b/packages/pigeon/lib/generator.dart
new file mode 100644
index 00000000000..02667e4a5c9
--- /dev/null
+++ b/packages/pigeon/lib/generator.dart
@@ -0,0 +1,13 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'ast.dart';
+
+/// A superclass of generator classes.
+///
+/// This provides the structure that is common across generators for different languages.
+abstract class Generator<T> {
+  /// Generates files for specified language with specified [languageOptions]
+  void generate(T languageOptions, Root root, StringSink sink);
+}
diff --git a/packages/pigeon/lib/generator_tools.dart b/packages/pigeon/lib/generator_tools.dart
index ea522eaa04d..b1ee06b01e8 100644
--- a/packages/pigeon/lib/generator_tools.dart
+++ b/packages/pigeon/lib/generator_tools.dart
@@ -9,7 +9,7 @@ import 'dart:mirrors';
 import 'ast.dart';
 
 /// The current version of pigeon. This must match the version in pubspec.yaml.
-const String pigeonVersion = '4.2.16';
+const String pigeonVersion = '5.0.0';
 
 /// Read all the content from [stdin] to a String.
 String readStdin() {
@@ -497,3 +497,29 @@ Iterable<NamedType> getFieldsInSerializationOrder(Class klass) {
   // This returns the fields in the order they are declared in the pigeon file.
   return klass.fields;
 }
+
+/// Enum to specify which file will be generated for multi-file generators
+enum FileType {
+  /// header file.
+  header,
+
+  /// source file.
+  source,
+
+  /// file type is not applicable.
+  na,
+}
+
+/// Options for [Generator]'s that have multiple output file types.
+///
+/// Specifies which file to write as well as wraps all language options.
+class OutputFileOptions<T> {
+  /// Constructor.
+  OutputFileOptions({required this.fileType, required this.languageOptions});
+
+  /// To specify which file type should be created.
+  FileType fileType;
+
+  /// Options for specified language across all file types.
+  T languageOptions;
+}
diff --git a/packages/pigeon/lib/java_generator.dart b/packages/pigeon/lib/java_generator.dart
index c52d976cfdf..daca63876d2 100644
--- a/packages/pigeon/lib/java_generator.dart
+++ b/packages/pigeon/lib/java_generator.dart
@@ -4,6 +4,7 @@
 
 import 'ast.dart';
 import 'functional.dart';
+import 'generator.dart';
 import 'generator_tools.dart';
 import 'pigeon_lib.dart' show TaskQueueType;
 
@@ -84,6 +85,20 @@ class JavaOptions {
   }
 }
 
+/// Class that manages all Java code generation.
+class JavaGenerator extends Generator<JavaOptions> {
+  /// Instantiates a Java Generator.
+  JavaGenerator();
+
+  /// Generates Java files with specified [JavaOptions]
+  @override
+  void generate(JavaOptions languageOptions, Root root, StringSink sink,
+      {FileType fileType = FileType.na}) {
+    assert(fileType == FileType.na);
+    generateJava(languageOptions, root, sink);
+  }
+}
+
 /// Calculates the name of the codec that will be generated for [api].
 String _getCodecName(Api api) => '${api.name}Codec';
 
diff --git a/packages/pigeon/lib/kotlin_generator.dart b/packages/pigeon/lib/kotlin_generator.dart
index 1f52d3d22c3..18e08c7398a 100644
--- a/packages/pigeon/lib/kotlin_generator.dart
+++ b/packages/pigeon/lib/kotlin_generator.dart
@@ -4,6 +4,7 @@
 
 import 'ast.dart';
 import 'functional.dart';
+import 'generator.dart';
 import 'generator_tools.dart';
 import 'pigeon_lib.dart' show TaskQueueType;
 
@@ -64,6 +65,20 @@ class KotlinOptions {
   }
 }
 
+/// Class that manages all Kotlin code generation.
+class KotlinGenerator extends Generator<KotlinOptions> {
+  /// Instantiates a Kotlin Generator.
+  KotlinGenerator();
+
+  /// Generates Kotlin files with specified [KotlinOptions]
+  @override
+  void generate(KotlinOptions languageOptions, Root root, StringSink sink,
+      {FileType fileType = FileType.na}) {
+    assert(fileType == FileType.na);
+    generateKotlin(languageOptions, root, sink);
+  }
+}
+
 /// Calculates the name of the codec that will be generated for [api].
 String _getCodecName(Api api) => '${api.name}Codec';
 
diff --git a/packages/pigeon/lib/objc_generator.dart b/packages/pigeon/lib/objc_generator.dart
index e8de7c1154c..3d7e3a64da2 100644
--- a/packages/pigeon/lib/objc_generator.dart
+++ b/packages/pigeon/lib/objc_generator.dart
@@ -4,6 +4,7 @@
 
 import 'ast.dart';
 import 'functional.dart';
+import 'generator.dart';
 import 'generator_tools.dart';
 import 'pigeon_lib.dart' show Error, TaskQueueType;
 
@@ -18,14 +19,14 @@ const DocumentCommentSpecification _docCommentSpec =
 class ObjcOptions {
   /// Parametric constructor for ObjcOptions.
   const ObjcOptions({
-    this.header,
+    this.headerIncludePath,
     this.prefix,
     this.copyrightHeader,
   });
 
   /// The path to the header that will get placed in the source filed (example:
   /// "foo.h").
-  final String? header;
+  final String? headerIncludePath;
 
   /// Prefix that will be appended before all generated classes and protocols.
   final String? prefix;
@@ -39,7 +40,7 @@ class ObjcOptions {
     final Iterable<dynamic>? copyrightHeader =
         map['copyrightHeader'] as Iterable<dynamic>?;
     return ObjcOptions(
-      header: map['header'] as String?,
+      headerIncludePath: map['header'] as String?,
       prefix: map['prefix'] as String?,
       copyrightHeader: copyrightHeader?.cast<String>(),
     );
@@ -49,7 +50,7 @@ class ObjcOptions {
   /// `x = ObjcOptions.fromMap(x.toMap())`.
   Map<String, Object> toMap() {
     final Map<String, Object> result = <String, Object>{
-      if (header != null) 'header': header!,
+      if (headerIncludePath != null) 'header': headerIncludePath!,
       if (prefix != null) 'prefix': prefix!,
       if (copyrightHeader != null) 'copyrightHeader': copyrightHeader!,
     };
@@ -63,6 +64,26 @@ class ObjcOptions {
   }
 }
 
+/// Class that manages all Objc header code generation.
+class ObjcGenerator extends Generator<OutputFileOptions<ObjcOptions>> {
+  /// Instantiates a Objc Generator.
+  ObjcGenerator();
+
+  /// Generates Objc files with specified [OutputFileOptions<ObjcOptions>]
+  @override
+  void generate(OutputFileOptions<ObjcOptions> languageOptions, Root root,
+      StringSink sink) {
+    final FileType fileType = languageOptions.fileType;
+    assert(fileType == FileType.header || fileType == FileType.source);
+
+    if (fileType == FileType.header) {
+      generateObjcHeader(languageOptions.languageOptions, root, sink);
+    } else {
+      generateObjcSource(languageOptions.languageOptions, root, sink);
+    }
+  }
+}
+
 /// Calculates the ObjC class name, possibly prefixed.
 String _className(String? prefix, String className) {
   if (prefix != null) {
@@ -890,7 +911,7 @@ void generateObjcSource(ObjcOptions options, Root root, StringSink sink) {
   }
 
   void writeImports() {
-    indent.writeln('#import "${options.header}"');
+    indent.writeln('#import "${options.headerIncludePath}"');
     indent.writeln('#import <Flutter/Flutter.h>');
   }
 
diff --git a/packages/pigeon/lib/pigeon_lib.dart b/packages/pigeon/lib/pigeon_lib.dart
index 5da91c4a7c5..5082dd19e8e 100644
--- a/packages/pigeon/lib/pigeon_lib.dart
+++ b/packages/pigeon/lib/pigeon_lib.dart
@@ -355,85 +355,116 @@ IOSink? _openSink(String? output) {
   return sink;
 }
 
-/// A generator that will write code to a sink based on the contents of [PigeonOptions].
-abstract class Generator {
-  /// Returns an [IOSink] instance to be written to if the [Generator] should
-  /// generate.  If it returns `null`, the [Generator] will be skipped.
-  IOSink? shouldGenerate(PigeonOptions options);
-
-  /// Write the generated code described in [root] to [sink] using the
-  /// [options].
-  void generate(StringSink sink, PigeonOptions options, Root root);
-
-  /// Generates errors that would only be appropriate for this [Generator]. For
-  /// example, maybe a certain feature isn't implemented in a [Generator] yet.
+/// An adapter that will call a generator to write code to a sink
+/// based on the contents of [PigeonOptions].
+abstract class GeneratorAdapter {
+  /// Constructor for [GeneratorAdapter]
+  GeneratorAdapter(this.fileTypeList);
+
+  /// A list of file types the generator should create.
+  List<FileType> fileTypeList;
+
+  /// Returns an [IOSink] instance to be written to
+  /// if the [GeneratorAdapter] should generate.
+  ///
+  /// If it returns `null`, the [GeneratorAdapter] will be skipped.
+  IOSink? shouldGenerate(PigeonOptions options, FileType fileType);
+
+  /// Write the generated code described in [root] to [sink] using the [options].
+  void generate(
+      StringSink sink, PigeonOptions options, Root root, FileType fileType);
+
+  /// Generates errors that would only be appropriate for this [GeneratorAdapter].
+  ///
+  /// For example, if a certain feature isn't implemented in a [GeneratorAdapter] yet.
   List<Error> validate(PigeonOptions options, Root root);
 }
 
 DartOptions _dartOptionsWithCopyrightHeader(
-    DartOptions? dartOptions, String? copyrightHeader) {
-  dartOptions = dartOptions ?? const DartOptions();
+    DartOptions? dartOptions, String? copyrightHeader,
+    {String? dartOutPath, String? testOutPath}) {
+  dartOptions = dartOptions ?? DartOptions();
   return dartOptions.merge(DartOptions(
+      sourceOutPath: dartOutPath,
+      testOutPath: testOutPath,
       copyrightHeader:
           copyrightHeader != null ? _lineReader(copyrightHeader) : null));
 }
 
-/// A [Generator] that generates the AST.
-class AstGenerator implements Generator {
-  /// Constructor for [AstGenerator].
-  const AstGenerator();
+/// A [GeneratorAdapter] that generates the AST.
+class AstGeneratorAdapter implements GeneratorAdapter {
+  /// Constructor for [AstGeneratorAdapter].
+  AstGeneratorAdapter();
+
+  @override
+  List<FileType> fileTypeList = const <FileType>[FileType.na];
 
   @override
-  void generate(StringSink sink, PigeonOptions options, Root root) {
+  void generate(
+      StringSink sink, PigeonOptions options, Root root, FileType fileType) {
     generateAst(root, sink);
   }
 
   @override
-  IOSink? shouldGenerate(PigeonOptions options) => _openSink(options.astOut);
+  IOSink? shouldGenerate(PigeonOptions options, FileType _) =>
+      _openSink(options.astOut);
 
   @override
   List<Error> validate(PigeonOptions options, Root root) => <Error>[];
 }
 
-/// A [Generator] that generates Dart source code.
-class DartGenerator implements Generator {
-  /// Constructor for [DartGenerator].
-  const DartGenerator();
+/// A [GeneratorAdapter] that generates Dart source code.
+class DartGeneratorAdapter implements GeneratorAdapter {
+  /// Constructor for [DartGeneratorAdapter].
+  DartGeneratorAdapter();
 
   @override
-  void generate(StringSink sink, PigeonOptions options, Root root) {
+  List<FileType> fileTypeList = const <FileType>[FileType.na];
+
+  @override
+  void generate(
+      StringSink sink, PigeonOptions options, Root root, FileType fileType) {
     final DartOptions dartOptionsWithHeader = _dartOptionsWithCopyrightHeader(
         options.dartOptions, options.copyrightHeader);
-    generateDart(dartOptionsWithHeader, root, sink);
+    final DartGenerator generator = DartGenerator();
+    generator.generate(dartOptionsWithHeader, root, sink);
   }
 
   @override
-  IOSink? shouldGenerate(PigeonOptions options) => _openSink(options.dartOut);
+  IOSink? shouldGenerate(PigeonOptions options, FileType _) =>
+      _openSink(options.dartOut);
 
   @override
   List<Error> validate(PigeonOptions options, Root root) => <Error>[];
 }
 
-/// A [Generator] that generates Dart test source code.
-class DartTestGenerator implements Generator {
-  /// Constructor for [DartTestGenerator].
-  const DartTestGenerator();
+/// A [GeneratorAdapter] that generates Dart test source code.
+class DartTestGeneratorAdapter implements GeneratorAdapter {
+  /// Constructor for [DartTestGeneratorAdapter].
+  DartTestGeneratorAdapter();
+
+  @override
+  List<FileType> fileTypeList = const <FileType>[FileType.na];
 
   @override
-  void generate(StringSink sink, PigeonOptions options, Root root) {
+  void generate(
+      StringSink sink, PigeonOptions options, Root root, FileType fileType) {
     final DartOptions dartOptionsWithHeader = _dartOptionsWithCopyrightHeader(
-        options.dartOptions, options.copyrightHeader);
-    generateTestDart(
+      options.dartOptions,
+      options.copyrightHeader,
+      dartOutPath: options.dartOut,
+      testOutPath: options.dartTestOut,
+    );
+    final DartGenerator testGenerator = DartGenerator();
+    testGenerator.generateTest(
       dartOptionsWithHeader,
       root,
       sink,
-      dartOutPath: options.dartOut!,
-      testOutPath: options.dartTestOut!,
     );
   }
 
   @override
-  IOSink? shouldGenerate(PigeonOptions options) {
+  IOSink? shouldGenerate(PigeonOptions options, FileType _) {
     if (options.dartTestOut != null) {
       return _openSink(options.dartTestOut);
     } else {
@@ -445,60 +476,55 @@ class DartTestGenerator implements Generator {
   List<Error> validate(PigeonOptions options, Root root) => <Error>[];
 }
 
-/// A [Generator] that generates Objective-C header code.
-class ObjcHeaderGenerator implements Generator {
-  /// Constructor for [ObjcHeaderGenerator].
-  const ObjcHeaderGenerator();
-
-  @override
-  void generate(StringSink sink, PigeonOptions options, Root root) {
-    final ObjcOptions objcOptions = options.objcOptions ?? const ObjcOptions();
-    final ObjcOptions objcOptionsWithHeader = objcOptions.merge(ObjcOptions(
-        copyrightHeader: options.copyrightHeader != null
-            ? _lineReader(options.copyrightHeader!)
-            : null));
-    generateObjcHeader(objcOptionsWithHeader, root, sink);
-  }
-
-  @override
-  IOSink? shouldGenerate(PigeonOptions options) =>
-      _openSink(options.objcHeaderOut);
+/// A [GeneratorAdapter] that generates Objective-C code.
+class ObjcGeneratorAdapter implements GeneratorAdapter {
+  /// Constructor for [ObjcGeneratorAdapter].
+  ObjcGeneratorAdapter(
+      {this.fileTypeList = const <FileType>[FileType.header, FileType.source]});
 
   @override
-  List<Error> validate(PigeonOptions options, Root root) =>
-      validateObjc(options.objcOptions!, root);
-}
-
-/// A [Generator] that generates Objective-C source code.
-class ObjcSourceGenerator implements Generator {
-  /// Constructor for [ObjcSourceGenerator].
-  const ObjcSourceGenerator();
+  List<FileType> fileTypeList;
 
   @override
-  void generate(StringSink sink, PigeonOptions options, Root root) {
+  void generate(
+      StringSink sink, PigeonOptions options, Root root, FileType fileType) {
     final ObjcOptions objcOptions = options.objcOptions ?? const ObjcOptions();
     final ObjcOptions objcOptionsWithHeader = objcOptions.merge(ObjcOptions(
-        copyrightHeader: options.copyrightHeader != null
-            ? _lineReader(options.copyrightHeader!)
-            : null));
-    generateObjcSource(objcOptionsWithHeader, root, sink);
+      copyrightHeader: options.copyrightHeader != null
+          ? _lineReader(options.copyrightHeader!)
+          : null,
+    ));
+    final OutputFileOptions<ObjcOptions> outputFileOptions =
+        OutputFileOptions<ObjcOptions>(
+            fileType: fileType, languageOptions: objcOptionsWithHeader);
+    final ObjcGenerator generator = ObjcGenerator();
+    generator.generate(outputFileOptions, root, sink);
   }
 
   @override
-  IOSink? shouldGenerate(PigeonOptions options) =>
-      _openSink(options.objcSourceOut);
+  IOSink? shouldGenerate(PigeonOptions options, FileType fileType) {
+    if (fileType == FileType.source) {
+      return _openSink(options.objcSourceOut);
+    } else {
+      return _openSink(options.objcHeaderOut);
+    }
+  }
 
   @override
   List<Error> validate(PigeonOptions options, Root root) => <Error>[];
 }
 
-/// A [Generator] that generates Java source code.
-class JavaGenerator implements Generator {
-  /// Constructor for [JavaGenerator].
-  const JavaGenerator();
+/// A [GeneratorAdapter] that generates Java source code.
+class JavaGeneratorAdapter implements GeneratorAdapter {
+  /// Constructor for [JavaGeneratorAdapter].
+  JavaGeneratorAdapter();
+
+  @override
+  List<FileType> fileTypeList = const <FileType>[FileType.na];
 
   @override
-  void generate(StringSink sink, PigeonOptions options, Root root) {
+  void generate(
+      StringSink sink, PigeonOptions options, Root root, FileType fileType) {
     JavaOptions javaOptions = options.javaOptions ?? const JavaOptions();
     javaOptions = javaOptions.merge(JavaOptions(
         className: javaOptions.className ??
@@ -506,104 +532,108 @@ class JavaGenerator implements Generator {
         copyrightHeader: options.copyrightHeader != null
             ? _lineReader(options.copyrightHeader!)
             : null));
-    generateJava(javaOptions, root, sink);
+    final JavaGenerator generator = JavaGenerator();
+    generator.generate(javaOptions, root, sink);
   }
 
   @override
-  IOSink? shouldGenerate(PigeonOptions options) => _openSink(options.javaOut);
+  IOSink? shouldGenerate(PigeonOptions options, FileType _) =>
+      _openSink(options.javaOut);
 
   @override
   List<Error> validate(PigeonOptions options, Root root) => <Error>[];
 }
 
-/// A [Generator] that generates Swift source code.
-class SwiftGenerator implements Generator {
-  /// Constructor for [SwiftGenerator].
-  const SwiftGenerator();
+/// A [GeneratorAdapter] that generates Swift source code.
+class SwiftGeneratorAdapter implements GeneratorAdapter {
+  /// Constructor for [SwiftGeneratorAdapter].
+  SwiftGeneratorAdapter();
 
   @override
-  void generate(StringSink sink, PigeonOptions options, Root root) {
+  List<FileType> fileTypeList = const <FileType>[FileType.na];
+
+  @override
+  void generate(
+      StringSink sink, PigeonOptions options, Root root, FileType fileType) {
     SwiftOptions swiftOptions = options.swiftOptions ?? const SwiftOptions();
     swiftOptions = swiftOptions.merge(SwiftOptions(
         copyrightHeader: options.copyrightHeader != null
             ? _lineReader(options.copyrightHeader!)
             : null));
-    generateSwift(swiftOptions, root, sink);
+    final SwiftGenerator generator = SwiftGenerator();
+    generator.generate(swiftOptions, root, sink);
   }
 
   @override
-  IOSink? shouldGenerate(PigeonOptions options) => _openSink(options.swiftOut);
+  IOSink? shouldGenerate(PigeonOptions options, FileType _) =>
+      _openSink(options.swiftOut);
 
   @override
   List<Error> validate(PigeonOptions options, Root root) => <Error>[];
 }
 
-/// A [Generator] that generates C++ header code.
-class CppHeaderGenerator implements Generator {
-  /// Constructor for [CppHeaderGenerator].
-  const CppHeaderGenerator();
-
-  @override
-  void generate(StringSink sink, PigeonOptions options, Root root) {
-    final CppOptions cppOptions = options.cppOptions ?? const CppOptions();
-    final CppOptions cppOptionsWithHeader = cppOptions.merge(CppOptions(
-        copyrightHeader: options.copyrightHeader != null
-            ? _lineReader(options.copyrightHeader!)
-            : null));
-    generateCppHeader(path.basenameWithoutExtension(options.cppHeaderOut!),
-        cppOptionsWithHeader, root, sink);
-  }
+/// A [GeneratorAdapter] that generates C++ source code.
+class CppGeneratorAdapter implements GeneratorAdapter {
+  /// Constructor for [CppGeneratorAdapter].
+  CppGeneratorAdapter(
+      {this.fileTypeList = const <FileType>[FileType.header, FileType.source]});
 
   @override
-  IOSink? shouldGenerate(PigeonOptions options) =>
-      _openSink(options.cppHeaderOut);
+  List<FileType> fileTypeList;
 
   @override
-  List<Error> validate(PigeonOptions options, Root root) =>
-      validateCpp(options.cppOptions!, root);
-}
-
-/// A [Generator] that generates C++ source code.
-class CppSourceGenerator implements Generator {
-  /// Constructor for [CppSourceGenerator].
-  const CppSourceGenerator();
-
-  @override
-  void generate(StringSink sink, PigeonOptions options, Root root) {
+  void generate(
+      StringSink sink, PigeonOptions options, Root root, FileType fileType) {
     final CppOptions cppOptions = options.cppOptions ?? const CppOptions();
     final CppOptions cppOptionsWithHeader = cppOptions.merge(CppOptions(
-        copyrightHeader: options.copyrightHeader != null
-            ? _lineReader(options.copyrightHeader!)
-            : null));
-    generateCppSource(cppOptionsWithHeader, root, sink);
+      copyrightHeader: options.copyrightHeader != null
+          ? _lineReader(options.copyrightHeader!)
+          : null,
+    ));
+    final OutputFileOptions<CppOptions> outputFileOptions =
+        OutputFileOptions<CppOptions>(
+            fileType: fileType, languageOptions: cppOptionsWithHeader);
+    final CppGenerator generator = CppGenerator();
+    generator.generate(outputFileOptions, root, sink);
   }
 
   @override
-  IOSink? shouldGenerate(PigeonOptions options) =>
-      _openSink(options.cppSourceOut);
+  IOSink? shouldGenerate(PigeonOptions options, FileType fileType) {
+    if (fileType == FileType.source) {
+      return _openSink(options.cppSourceOut);
+    } else {
+      return _openSink(options.cppHeaderOut);
+    }
+  }
 
   @override
   List<Error> validate(PigeonOptions options, Root root) => <Error>[];
 }
 
-/// A [Generator] that generates Kotlin source code.
-class KotlinGenerator implements Generator {
-  /// Constructor for [KotlinGenerator].
-  const KotlinGenerator();
+/// A [GeneratorAdapter] that generates Kotlin source code.
+class KotlinGeneratorAdapter implements GeneratorAdapter {
+  /// Constructor for [KotlinGeneratorAdapter].
+  KotlinGeneratorAdapter({this.fileTypeList = const <FileType>[FileType.na]});
+
+  @override
+  List<FileType> fileTypeList;
 
   @override
-  void generate(StringSink sink, PigeonOptions options, Root root) {
+  void generate(
+      StringSink sink, PigeonOptions options, Root root, FileType fileType) {
     KotlinOptions kotlinOptions =
         options.kotlinOptions ?? const KotlinOptions();
     kotlinOptions = kotlinOptions.merge(KotlinOptions(
         copyrightHeader: options.copyrightHeader != null
             ? _lineReader(options.copyrightHeader!)
             : null));
-    generateKotlin(kotlinOptions, root, sink);
+    final KotlinGenerator generator = KotlinGenerator();
+    generator.generate(kotlinOptions, root, sink);
   }
 
   @override
-  IOSink? shouldGenerate(PigeonOptions options) => _openSink(options.kotlinOut);
+  IOSink? shouldGenerate(PigeonOptions options, FileType _) =>
+      _openSink(options.kotlinOut);
 
   @override
   List<Error> validate(PigeonOptions options, Root root) => <Error>[];
@@ -1331,37 +1361,35 @@ ${_argParser.usage}''';
   }
 
   /// The 'main' entrypoint used by the command-line tool.  [args] are the
-  /// command-line arguments.  The optional parameter [generators] allows you to
+  /// command-line arguments.  The optional parameter [adapters] allows you to
   /// customize the generators that pigeon will use. The optional parameter
   /// [sdkPath] allows you to specify the Dart SDK path.
   static Future<int> run(List<String> args,
-      {List<Generator>? generators, String? sdkPath}) {
+      {List<GeneratorAdapter>? adapters, String? sdkPath}) {
     final PigeonOptions options = Pigeon.parseArgs(args);
-    return runWithOptions(options, generators: generators, sdkPath: sdkPath);
+    return runWithOptions(options, adapters: adapters, sdkPath: sdkPath);
   }
 
   /// The 'main' entrypoint used by external packages.  [options] is
-  /// used when running the code generator.  The optional parameter [generators] allows you to
+  /// used when running the code generator.  The optional parameter [adapters] allows you to
   /// customize the generators that pigeon will use. The optional parameter
   /// [sdkPath] allows you to specify the Dart SDK path.
   static Future<int> runWithOptions(PigeonOptions options,
-      {List<Generator>? generators, String? sdkPath}) async {
+      {List<GeneratorAdapter>? adapters, String? sdkPath}) async {
     final Pigeon pigeon = Pigeon.setup();
     if (options.debugGenerators ?? false) {
       generator_tools.debugGenerators = true;
     }
-    final List<Generator> safeGenerators = generators ??
-        <Generator>[
-          const DartGenerator(),
-          const JavaGenerator(),
-          const SwiftGenerator(),
-          const KotlinGenerator(),
-          const CppHeaderGenerator(),
-          const CppSourceGenerator(),
-          const DartTestGenerator(),
-          const ObjcHeaderGenerator(),
-          const ObjcSourceGenerator(),
-          const AstGenerator(),
+    final List<GeneratorAdapter> safeGeneratorAdapters = adapters ??
+        <GeneratorAdapter>[
+          DartGeneratorAdapter(),
+          JavaGeneratorAdapter(),
+          SwiftGeneratorAdapter(),
+          KotlinGeneratorAdapter(),
+          CppGeneratorAdapter(),
+          DartTestGeneratorAdapter(),
+          ObjcGeneratorAdapter(),
+          AstGeneratorAdapter(),
         ];
     _executeConfigurePigeon(options);
 
@@ -1383,12 +1411,12 @@ ${_argParser.usage}''';
       }
     }
 
-    for (final Generator generator in safeGenerators) {
-      final IOSink? sink = generator.shouldGenerate(options);
+    for (final GeneratorAdapter adapter in safeGeneratorAdapters) {
+      final IOSink? sink = adapter.shouldGenerate(options, FileType.source);
       if (sink != null) {
-        final List<Error> generatorErrors =
-            generator.validate(options, parseResults.root);
-        errors.addAll(generatorErrors);
+        final List<Error> adapterErrors =
+            adapter.validate(options, parseResults.root);
+        errors.addAll(adapterErrors);
         await releaseSink(sink);
       }
     }
@@ -1415,22 +1443,24 @@ ${_argParser.usage}''';
 
     if (options.objcHeaderOut != null) {
       options = options.merge(PigeonOptions(
-          objcOptions: options.objcOptions!.merge(
-              ObjcOptions(header: path.basename(options.objcHeaderOut!)))));
+          objcOptions: options.objcOptions!.merge(ObjcOptions(
+              headerIncludePath: path.basename(options.objcHeaderOut!)))));
     }
 
     if (options.cppHeaderOut != null) {
       options = options.merge(PigeonOptions(
-          cppOptions: options.cppOptions!.merge(
-              CppOptions(header: path.basename(options.cppHeaderOut!)))));
+          cppOptions: options.cppOptions!.merge(CppOptions(
+              headerIncludePath: path.basename(options.cppHeaderOut!)))));
     }
 
-    for (final Generator generator in safeGenerators) {
-      final IOSink? sink = generator.shouldGenerate(options);
-      if (sink != null) {
-        generator.generate(sink, options, parseResults.root);
-        await sink.flush();
-        await releaseSink(sink);
+    for (final GeneratorAdapter adapter in safeGeneratorAdapters) {
+      for (final FileType fileType in adapter.fileTypeList) {
+        final IOSink? sink = adapter.shouldGenerate(options, fileType);
+        if (sink != null) {
+          adapter.generate(sink, options, parseResults.root, fileType);
+          await sink.flush();
+          await releaseSink(sink);
+        }
       }
     }
 
diff --git a/packages/pigeon/lib/swift_generator.dart b/packages/pigeon/lib/swift_generator.dart
index 0311b8de21d..77fff7e2fac 100644
--- a/packages/pigeon/lib/swift_generator.dart
+++ b/packages/pigeon/lib/swift_generator.dart
@@ -4,6 +4,7 @@
 
 import 'ast.dart';
 import 'functional.dart';
+import 'generator.dart';
 import 'generator_tools.dart';
 
 /// Documentation comment open symbol.
@@ -47,6 +48,20 @@ class SwiftOptions {
   }
 }
 
+/// Class that manages all Swift code generation.
+class SwiftGenerator extends Generator<SwiftOptions> {
+  /// Instantiates a Swift Generator.
+  SwiftGenerator();
+
+  /// Generates Swift files with specified [SwiftOptions]
+  @override
+  void generate(SwiftOptions languageOptions, Root root, StringSink sink,
+      {FileType fileType = FileType.na}) {
+    assert(fileType == FileType.na);
+    generateSwift(languageOptions, root, sink);
+  }
+}
+
 /// Calculates the name of the codec that will be generated for [api].
 String _getCodecName(Api api) => '${api.name}Codec';
 
diff --git a/packages/pigeon/mock_handler_tester/test/message.dart b/packages/pigeon/mock_handler_tester/test/message.dart
index f5ce56c7f0b..4f6c9d14457 100644
--- a/packages/pigeon/mock_handler_tester/test/message.dart
+++ b/packages/pigeon/mock_handler_tester/test/message.dart
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
-// Autogenerated from Pigeon (v4.2.15), do not edit directly.
+// Autogenerated from Pigeon (v5.0.0), do not edit directly.
 // See also: https://pub.dev/packages/pigeon
 // ignore_for_file: public_member_api_docs, non_constant_identifier_names, avoid_as, unused_import, unnecessary_parenthesis, prefer_null_aware_operators, omit_local_variable_types, unused_shown_name, unnecessary_import
 import 'dart:async';
diff --git a/packages/pigeon/mock_handler_tester/test/test.dart b/packages/pigeon/mock_handler_tester/test/test.dart
index 8fcd5ae8d66..9b97826b605 100644
--- a/packages/pigeon/mock_handler_tester/test/test.dart
+++ b/packages/pigeon/mock_handler_tester/test/test.dart
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
-// Autogenerated from Pigeon (v4.2.15), do not edit directly.
+// Autogenerated from Pigeon (v5.0.0), do not edit directly.
 // See also: https://pub.dev/packages/pigeon
 // ignore_for_file: public_member_api_docs, non_constant_identifier_names, avoid_as, unused_import, unnecessary_parenthesis, unnecessary_import
 // ignore_for_file: avoid_relative_lib_imports
diff --git a/packages/pigeon/platform_tests/alternate_language_test_plugin/android/src/main/java/com/example/alternate_language_test_plugin/CoreTests.java b/packages/pigeon/platform_tests/alternate_language_test_plugin/android/src/main/java/com/example/alternate_language_test_plugin/CoreTests.java
index c2f03631815..95b0e2a9509 100644
--- a/packages/pigeon/platform_tests/alternate_language_test_plugin/android/src/main/java/com/example/alternate_language_test_plugin/CoreTests.java
+++ b/packages/pigeon/platform_tests/alternate_language_test_plugin/android/src/main/java/com/example/alternate_language_test_plugin/CoreTests.java
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
-// Autogenerated from Pigeon (v4.2.16), do not edit directly.
+// Autogenerated from Pigeon (v5.0.0), do not edit directly.
 // See also: https://pub.dev/packages/pigeon
 
 package com.example.alternate_language_test_plugin;
diff --git a/packages/pigeon/platform_tests/alternate_language_test_plugin/ios/Classes/CoreTests.gen.h b/packages/pigeon/platform_tests/alternate_language_test_plugin/ios/Classes/CoreTests.gen.h
index 0e98e89469a..1def5e7af69 100644
--- a/packages/pigeon/platform_tests/alternate_language_test_plugin/ios/Classes/CoreTests.gen.h
+++ b/packages/pigeon/platform_tests/alternate_language_test_plugin/ios/Classes/CoreTests.gen.h
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
-// Autogenerated from Pigeon (v4.2.16), do not edit directly.
+// Autogenerated from Pigeon (v5.0.0), do not edit directly.
 // See also: https://pub.dev/packages/pigeon
 #import <Foundation/Foundation.h>
 @protocol FlutterBinaryMessenger;
diff --git a/packages/pigeon/platform_tests/alternate_language_test_plugin/ios/Classes/CoreTests.gen.m b/packages/pigeon/platform_tests/alternate_language_test_plugin/ios/Classes/CoreTests.gen.m
index fa13afaf750..244b1e236c5 100644
--- a/packages/pigeon/platform_tests/alternate_language_test_plugin/ios/Classes/CoreTests.gen.m
+++ b/packages/pigeon/platform_tests/alternate_language_test_plugin/ios/Classes/CoreTests.gen.m
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
-// Autogenerated from Pigeon (v4.2.16), do not edit directly.
+// Autogenerated from Pigeon (v5.0.0), do not edit directly.
 // See also: https://pub.dev/packages/pigeon
 #import "CoreTests.gen.h"
 #import <Flutter/Flutter.h>
diff --git a/packages/pigeon/platform_tests/flutter_null_safe_unit_tests/lib/core_tests.gen.dart b/packages/pigeon/platform_tests/flutter_null_safe_unit_tests/lib/core_tests.gen.dart
index 2bca40161b1..fe0fe3335ea 100644
--- a/packages/pigeon/platform_tests/flutter_null_safe_unit_tests/lib/core_tests.gen.dart
+++ b/packages/pigeon/platform_tests/flutter_null_safe_unit_tests/lib/core_tests.gen.dart
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
-// Autogenerated from Pigeon (v4.2.15), do not edit directly.
+// Autogenerated from Pigeon (v5.0.0), do not edit directly.
 // See also: https://pub.dev/packages/pigeon
 // ignore_for_file: public_member_api_docs, non_constant_identifier_names, avoid_as, unused_import, unnecessary_parenthesis, prefer_null_aware_operators, omit_local_variable_types, unused_shown_name, unnecessary_import
 import 'dart:async';
@@ -205,14 +205,11 @@ class _HostIntegrationCoreApiCodec extends StandardMessageCodec {
     if (value is AllNullableTypes) {
       buffer.putUint8(128);
       writeValue(buffer, value.encode());
-    } else if (value is AllNullableTypes) {
-      buffer.putUint8(129);
-      writeValue(buffer, value.encode());
     } else if (value is AllNullableTypesWrapper) {
-      buffer.putUint8(130);
+      buffer.putUint8(129);
       writeValue(buffer, value.encode());
     } else if (value is AllTypes) {
-      buffer.putUint8(131);
+      buffer.putUint8(130);
       writeValue(buffer, value.encode());
     } else {
       super.writeValue(buffer, value);
@@ -226,12 +223,9 @@ class _HostIntegrationCoreApiCodec extends StandardMessageCodec {
         return AllNullableTypes.decode(readValue(buffer)!);
 
       case 129:
-        return AllNullableTypes.decode(readValue(buffer)!);
-
-      case 130:
         return AllNullableTypesWrapper.decode(readValue(buffer)!);
 
-      case 131:
+      case 130:
         return AllTypes.decode(readValue(buffer)!);
 
       default:
@@ -489,6 +483,34 @@ class HostIntegrationCoreApi {
     }
   }
 
+  /// Returns the passed in generic Object.
+  Future<Object> echoObject(Object arg_anObject) async {
+    final BasicMessageChannel<Object?> channel = BasicMessageChannel<Object?>(
+        'dev.flutter.pigeon.HostIntegrationCoreApi.echoObject', codec,
+        binaryMessenger: _binaryMessenger);
+    final List<Object?>? replyList =
+        await channel.send(<Object?>[arg_anObject]) as List<Object?>?;
+    if (replyList == null) {
+      throw PlatformException(
+        code: 'channel-error',
+        message: 'Unable to establish connection on channel.',
+      );
+    } else if (replyList.length > 1) {
+      throw PlatformException(
+        code: replyList[0]! as String,
+        message: replyList[1] as String?,
+        details: replyList[2],
+      );
+    } else if (replyList[0] == null) {
+      throw PlatformException(
+        code: 'null-error',
+        message: 'Host platform returned null value for non-null return value.',
+      );
+    } else {
+      return replyList[0]!;
+    }
+  }
+
   /// Returns the inner `aString` value from the wrapped object, to test
   /// sending of nested objects.
   Future<String?> extractNestedNullableString(
@@ -694,6 +716,29 @@ class HostIntegrationCoreApi {
     }
   }
 
+  /// Returns the passed in generic Object.
+  Future<Object?> echoNullableObject(Object? arg_aNullableObject) async {
+    final BasicMessageChannel<Object?> channel = BasicMessageChannel<Object?>(
+        'dev.flutter.pigeon.HostIntegrationCoreApi.echoNullableObject', codec,
+        binaryMessenger: _binaryMessenger);
+    final List<Object?>? replyList =
+        await channel.send(<Object?>[arg_aNullableObject]) as List<Object?>?;
+    if (replyList == null) {
+      throw PlatformException(
+        code: 'channel-error',
+        message: 'Unable to establish connection on channel.',
+      );
+    } else if (replyList.length > 1) {
+      throw PlatformException(
+        code: replyList[0]! as String,
+        message: replyList[1] as String?,
+        details: replyList[2],
+      );
+    } else {
+      return replyList[0];
+    }
+  }
+
   /// A no-op function taking no arguments and returning no value, to sanity
   /// test basic asynchronous calling.
   Future<void> noopAsync() async {
diff --git a/packages/pigeon/platform_tests/flutter_null_safe_unit_tests/lib/multiple_arity.gen.dart b/packages/pigeon/platform_tests/flutter_null_safe_unit_tests/lib/multiple_arity.gen.dart
index e8486ceac4e..e92ab29cebd 100644
--- a/packages/pigeon/platform_tests/flutter_null_safe_unit_tests/lib/multiple_arity.gen.dart
+++ b/packages/pigeon/platform_tests/flutter_null_safe_unit_tests/lib/multiple_arity.gen.dart
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
-// Autogenerated from Pigeon (v4.2.15), do not edit directly.
+// Autogenerated from Pigeon (v5.0.0), do not edit directly.
 // See also: https://pub.dev/packages/pigeon
 // ignore_for_file: public_member_api_docs, non_constant_identifier_names, avoid_as, unused_import, unnecessary_parenthesis, prefer_null_aware_operators, omit_local_variable_types, unused_shown_name, unnecessary_import
 import 'dart:async';
diff --git a/packages/pigeon/platform_tests/flutter_null_safe_unit_tests/lib/non_null_fields.gen.dart b/packages/pigeon/platform_tests/flutter_null_safe_unit_tests/lib/non_null_fields.gen.dart
index f972b5472e2..1ff71bfa346 100644
--- a/packages/pigeon/platform_tests/flutter_null_safe_unit_tests/lib/non_null_fields.gen.dart
+++ b/packages/pigeon/platform_tests/flutter_null_safe_unit_tests/lib/non_null_fields.gen.dart
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
-// Autogenerated from Pigeon (v4.2.15), do not edit directly.
+// Autogenerated from Pigeon (v5.0.0), do not edit directly.
 // See also: https://pub.dev/packages/pigeon
 // ignore_for_file: public_member_api_docs, non_constant_identifier_names, avoid_as, unused_import, unnecessary_parenthesis, prefer_null_aware_operators, omit_local_variable_types, unused_shown_name, unnecessary_import
 import 'dart:async';
diff --git a/packages/pigeon/platform_tests/flutter_null_safe_unit_tests/lib/null_fields.gen.dart b/packages/pigeon/platform_tests/flutter_null_safe_unit_tests/lib/null_fields.gen.dart
index 50db20b91f8..88f4611e746 100644
--- a/packages/pigeon/platform_tests/flutter_null_safe_unit_tests/lib/null_fields.gen.dart
+++ b/packages/pigeon/platform_tests/flutter_null_safe_unit_tests/lib/null_fields.gen.dart
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
-// Autogenerated from Pigeon (v4.2.15), do not edit directly.
+// Autogenerated from Pigeon (v5.0.0), do not edit directly.
 // See also: https://pub.dev/packages/pigeon
 // ignore_for_file: public_member_api_docs, non_constant_identifier_names, avoid_as, unused_import, unnecessary_parenthesis, prefer_null_aware_operators, omit_local_variable_types, unused_shown_name, unnecessary_import
 import 'dart:async';
diff --git a/packages/pigeon/platform_tests/flutter_null_safe_unit_tests/lib/null_safe_pigeon.dart b/packages/pigeon/platform_tests/flutter_null_safe_unit_tests/lib/null_safe_pigeon.dart
index b54be15aafb..13fe926bcf1 100644
--- a/packages/pigeon/platform_tests/flutter_null_safe_unit_tests/lib/null_safe_pigeon.dart
+++ b/packages/pigeon/platform_tests/flutter_null_safe_unit_tests/lib/null_safe_pigeon.dart
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
-// Autogenerated from Pigeon (v4.2.15), do not edit directly.
+// Autogenerated from Pigeon (v5.0.0), do not edit directly.
 // See also: https://pub.dev/packages/pigeon
 // ignore_for_file: public_member_api_docs, non_constant_identifier_names, avoid_as, unused_import, unnecessary_parenthesis, prefer_null_aware_operators, omit_local_variable_types, unused_shown_name, unnecessary_import
 import 'dart:async';
diff --git a/packages/pigeon/platform_tests/flutter_null_safe_unit_tests/lib/nullable_returns.gen.dart b/packages/pigeon/platform_tests/flutter_null_safe_unit_tests/lib/nullable_returns.gen.dart
index 8ddfef08b4c..be1979c8adf 100644
--- a/packages/pigeon/platform_tests/flutter_null_safe_unit_tests/lib/nullable_returns.gen.dart
+++ b/packages/pigeon/platform_tests/flutter_null_safe_unit_tests/lib/nullable_returns.gen.dart
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
-// Autogenerated from Pigeon (v4.2.15), do not edit directly.
+// Autogenerated from Pigeon (v5.0.0), do not edit directly.
 // See also: https://pub.dev/packages/pigeon
 // ignore_for_file: public_member_api_docs, non_constant_identifier_names, avoid_as, unused_import, unnecessary_parenthesis, prefer_null_aware_operators, omit_local_variable_types, unused_shown_name, unnecessary_import
 import 'dart:async';
diff --git a/packages/pigeon/platform_tests/flutter_null_safe_unit_tests/lib/primitive.dart b/packages/pigeon/platform_tests/flutter_null_safe_unit_tests/lib/primitive.dart
index 149c54c68ed..36a569e4f46 100644
--- a/packages/pigeon/platform_tests/flutter_null_safe_unit_tests/lib/primitive.dart
+++ b/packages/pigeon/platform_tests/flutter_null_safe_unit_tests/lib/primitive.dart
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
-// Autogenerated from Pigeon (v4.2.15), do not edit directly.
+// Autogenerated from Pigeon (v5.0.0), do not edit directly.
 // See also: https://pub.dev/packages/pigeon
 // ignore_for_file: public_member_api_docs, non_constant_identifier_names, avoid_as, unused_import, unnecessary_parenthesis, prefer_null_aware_operators, omit_local_variable_types, unused_shown_name, unnecessary_import
 import 'dart:async';
diff --git a/packages/pigeon/platform_tests/shared_test_plugin_code/lib/src/generated/core_tests.gen.dart b/packages/pigeon/platform_tests/shared_test_plugin_code/lib/src/generated/core_tests.gen.dart
index 377a02e57f7..fe0fe3335ea 100644
--- a/packages/pigeon/platform_tests/shared_test_plugin_code/lib/src/generated/core_tests.gen.dart
+++ b/packages/pigeon/platform_tests/shared_test_plugin_code/lib/src/generated/core_tests.gen.dart
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
-// Autogenerated from Pigeon (v4.2.16), do not edit directly.
+// Autogenerated from Pigeon (v5.0.0), do not edit directly.
 // See also: https://pub.dev/packages/pigeon
 // ignore_for_file: public_member_api_docs, non_constant_identifier_names, avoid_as, unused_import, unnecessary_parenthesis, prefer_null_aware_operators, omit_local_variable_types, unused_shown_name, unnecessary_import
 import 'dart:async';
diff --git a/packages/pigeon/platform_tests/test_plugin/android/src/main/kotlin/com/example/test_plugin/CoreTests.gen.kt b/packages/pigeon/platform_tests/test_plugin/android/src/main/kotlin/com/example/test_plugin/CoreTests.gen.kt
index 5b33490f65a..61a957c8b55 100644
--- a/packages/pigeon/platform_tests/test_plugin/android/src/main/kotlin/com/example/test_plugin/CoreTests.gen.kt
+++ b/packages/pigeon/platform_tests/test_plugin/android/src/main/kotlin/com/example/test_plugin/CoreTests.gen.kt
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 // 
-// Autogenerated from Pigeon (v4.2.16), do not edit directly.
+// Autogenerated from Pigeon (v5.0.0), do not edit directly.
 // See also: https://pub.dev/packages/pigeon
 
 package com.example.test_plugin
diff --git a/packages/pigeon/platform_tests/test_plugin/ios/Classes/CoreTests.gen.swift b/packages/pigeon/platform_tests/test_plugin/ios/Classes/CoreTests.gen.swift
index b44380ded81..844e541a562 100644
--- a/packages/pigeon/platform_tests/test_plugin/ios/Classes/CoreTests.gen.swift
+++ b/packages/pigeon/platform_tests/test_plugin/ios/Classes/CoreTests.gen.swift
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 // 
-// Autogenerated from Pigeon (v4.2.16), do not edit directly.
+// Autogenerated from Pigeon (v5.0.0), do not edit directly.
 // See also: https://pub.dev/packages/pigeon
 
 import Foundation
diff --git a/packages/pigeon/platform_tests/test_plugin/macos/Classes/CoreTests.gen.swift b/packages/pigeon/platform_tests/test_plugin/macos/Classes/CoreTests.gen.swift
index b44380ded81..844e541a562 100644
--- a/packages/pigeon/platform_tests/test_plugin/macos/Classes/CoreTests.gen.swift
+++ b/packages/pigeon/platform_tests/test_plugin/macos/Classes/CoreTests.gen.swift
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 // 
-// Autogenerated from Pigeon (v4.2.16), do not edit directly.
+// Autogenerated from Pigeon (v5.0.0), do not edit directly.
 // See also: https://pub.dev/packages/pigeon
 
 import Foundation
diff --git a/packages/pigeon/platform_tests/test_plugin/windows/pigeon/core_tests.gen.cpp b/packages/pigeon/platform_tests/test_plugin/windows/pigeon/core_tests.gen.cpp
index a70c9377311..110c75e358d 100644
--- a/packages/pigeon/platform_tests/test_plugin/windows/pigeon/core_tests.gen.cpp
+++ b/packages/pigeon/platform_tests/test_plugin/windows/pigeon/core_tests.gen.cpp
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
-// Autogenerated from Pigeon (v4.2.16), do not edit directly.
+// Autogenerated from Pigeon (v5.0.0), do not edit directly.
 // See also: https://pub.dev/packages/pigeon
 
 #undef _HAS_EXCEPTIONS
diff --git a/packages/pigeon/platform_tests/test_plugin/windows/pigeon/core_tests.gen.h b/packages/pigeon/platform_tests/test_plugin/windows/pigeon/core_tests.gen.h
index 67b36263a85..527a0ff45c8 100644
--- a/packages/pigeon/platform_tests/test_plugin/windows/pigeon/core_tests.gen.h
+++ b/packages/pigeon/platform_tests/test_plugin/windows/pigeon/core_tests.gen.h
@@ -2,11 +2,11 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
-// Autogenerated from Pigeon (v4.2.16), do not edit directly.
+// Autogenerated from Pigeon (v5.0.0), do not edit directly.
 // See also: https://pub.dev/packages/pigeon
 
-#ifndef PIGEON_CORE_TESTS_GEN_CORE_TESTS_PIGEONTEST_H_
-#define PIGEON_CORE_TESTS_GEN_CORE_TESTS_PIGEONTEST_H_
+#ifndef PIGEON_CORE_TESTS_PIGEONTEST_H_
+#define PIGEON_CORE_TESTS_PIGEONTEST_H_
 #include <flutter/basic_message_channel.h>
 #include <flutter/binary_messenger.h>
 #include <flutter/encodable_value.h>
@@ -412,4 +412,4 @@ class HostTrivialApi {
   HostTrivialApi() = default;
 };
 }  // namespace core_tests_pigeontest
-#endif  // PIGEON_CORE_TESTS_GEN_CORE_TESTS_PIGEONTEST_H_
+#endif  // PIGEON_CORE_TESTS_PIGEONTEST_H_
diff --git a/packages/pigeon/pubspec.yaml b/packages/pigeon/pubspec.yaml
index 886f56a6ea0..e4ada89edd1 100644
--- a/packages/pigeon/pubspec.yaml
+++ b/packages/pigeon/pubspec.yaml
@@ -2,7 +2,7 @@ name: pigeon
 description: Code generator tool to make communication between Flutter and the host platform type-safe and easier.
 repository: https://github.com/flutter/packages/tree/main/packages/pigeon
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3Apigeon
-version: 4.2.16 # This must match the version in lib/generator_tools.dart
+version: 5.0.0 # This must match the version in lib/generator_tools.dart
 
 environment:
   sdk: ">=2.12.0 <3.0.0"
diff --git a/packages/pigeon/test/cpp_generator_test.dart b/packages/pigeon/test/cpp_generator_test.dart
index 4733c1f4bf0..172ce2ea3fe 100644
--- a/packages/pigeon/test/cpp_generator_test.dart
+++ b/packages/pigeon/test/cpp_generator_test.dart
@@ -45,7 +45,7 @@ void main() {
     ], enums: <Enum>[]);
     {
       final StringBuffer sink = StringBuffer();
-      generateCppHeader('', const CppOptions(), root, sink);
+      generateCppHeader(const CppOptions(), root, sink);
       final String code = sink.toString();
       expect(code, contains('class Input'));
       expect(code, contains('class Output'));
@@ -101,7 +101,7 @@ void main() {
     ], enums: <Enum>[]);
     {
       final StringBuffer sink = StringBuffer();
-      generateCppHeader('', const CppOptions(), root, sink);
+      generateCppHeader(const CppOptions(), root, sink);
       final String code = sink.toString();
       // Method name and argument names should be adjusted.
       expect(code, contains(' DoSomething(const Input& some_input)'));
@@ -144,7 +144,7 @@ void main() {
     ], classes: <Class>[], enums: <Enum>[]);
     {
       final StringBuffer sink = StringBuffer();
-      generateCppHeader('', const CppOptions(), root, sink);
+      generateCppHeader(const CppOptions(), root, sink);
       final String code = sink.toString();
 
       expect(
@@ -184,7 +184,7 @@ void main() {
     ], classes: <Class>[], enums: <Enum>[]);
     {
       final StringBuffer sink = StringBuffer();
-      generateCppHeader('', const CppOptions(), root, sink);
+      generateCppHeader(const CppOptions(), root, sink);
       final String code = sink.toString();
 
       expect(
@@ -238,7 +238,7 @@ void main() {
     ], enums: <Enum>[]);
     {
       final StringBuffer sink = StringBuffer();
-      generateCppHeader('', const CppOptions(), root, sink);
+      generateCppHeader(const CppOptions(), root, sink);
       final String code = sink.toString();
       expect(code, isNot(contains('){')));
       expect(code, isNot(contains('const{')));
@@ -271,7 +271,7 @@ void main() {
     ], classes: <Class>[], enums: <Enum>[]);
     {
       final StringBuffer sink = StringBuffer();
-      generateCppHeader('', const CppOptions(), root, sink);
+      generateCppHeader(const CppOptions(), root, sink);
       final String code = sink.toString();
       expect(code, contains('''
 #include <flutter/basic_message_channel.h>
@@ -286,7 +286,8 @@ void main() {
     }
     {
       final StringBuffer sink = StringBuffer();
-      generateCppSource(const CppOptions(header: 'a_header.h'), root, sink);
+      generateCppSource(
+          const CppOptions(headerIncludePath: 'a_header.h'), root, sink);
       final String code = sink.toString();
       expect(code, contains('''
 #include "a_header.h"
@@ -322,7 +323,7 @@ void main() {
     ], classes: <Class>[], enums: <Enum>[]);
     {
       final StringBuffer sink = StringBuffer();
-      generateCppHeader('', const CppOptions(namespace: 'foo'), root, sink);
+      generateCppHeader(const CppOptions(namespace: 'foo'), root, sink);
       final String code = sink.toString();
       expect(code, contains('namespace foo {'));
       expect(code, contains('}  // namespace foo'));
@@ -390,7 +391,7 @@ void main() {
     ], enums: <Enum>[]);
     {
       final StringBuffer sink = StringBuffer();
-      generateCppHeader('', const CppOptions(), root, sink);
+      generateCppHeader(const CppOptions(), root, sink);
       final String code = sink.toString();
       // Getters should return const pointers.
       expect(code, contains('const bool* nullable_bool()'));
@@ -521,7 +522,7 @@ void main() {
     ], enums: <Enum>[]);
     {
       final StringBuffer sink = StringBuffer();
-      generateCppHeader('', const CppOptions(), root, sink);
+      generateCppHeader(const CppOptions(), root, sink);
       final String code = sink.toString();
       // POD getters should return copies references.
       expect(code, contains('bool non_nullable_bool()'));
@@ -644,7 +645,7 @@ void main() {
     ], enums: <Enum>[]);
     {
       final StringBuffer sink = StringBuffer();
-      generateCppHeader('', const CppOptions(), root, sink);
+      generateCppHeader(const CppOptions(), root, sink);
       final String code = sink.toString();
       expect(
           code, contains('ErrorOr<std::optional<bool>> ReturnNullableBool()'));
@@ -749,7 +750,7 @@ void main() {
     ], enums: <Enum>[]);
     {
       final StringBuffer sink = StringBuffer();
-      generateCppHeader('', const CppOptions(), root, sink);
+      generateCppHeader(const CppOptions(), root, sink);
       final String code = sink.toString();
       expect(code, contains('ErrorOr<bool> ReturnBool()'));
       expect(code, contains('ErrorOr<int64_t> ReturnInt()'));
@@ -831,7 +832,7 @@ void main() {
     ], enums: <Enum>[]);
     {
       final StringBuffer sink = StringBuffer();
-      generateCppHeader('', const CppOptions(), root, sink);
+      generateCppHeader(const CppOptions(), root, sink);
       final String code = sink.toString();
       expect(
           code,
@@ -962,7 +963,7 @@ void main() {
     ], enums: <Enum>[]);
     {
       final StringBuffer sink = StringBuffer();
-      generateCppHeader('', const CppOptions(), root, sink);
+      generateCppHeader(const CppOptions(), root, sink);
       final String code = sink.toString();
       expect(
           code,
@@ -1148,7 +1149,7 @@ void main() {
       ],
     );
     final StringBuffer sink = StringBuffer();
-    generateCppHeader('foo', const CppOptions(), root, sink);
+    generateCppHeader(const CppOptions(headerIncludePath: 'foo'), root, sink);
     final String code = sink.toString();
     for (final String comment in comments) {
       expect(code, contains('//$comment'));
@@ -1183,7 +1184,7 @@ void main() {
       enums: <Enum>[],
     );
     final StringBuffer sink = StringBuffer();
-    generateCppHeader('', const CppOptions(), root, sink);
+    generateCppHeader(const CppOptions(), root, sink);
     final String code = sink.toString();
     expect(code, isNot(contains(' : public flutter::StandardCodecSerializer')));
   });
@@ -1225,7 +1226,7 @@ void main() {
       ])
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
-    generateCppHeader('', const CppOptions(), root, sink);
+    generateCppHeader(const CppOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains(' : public flutter::StandardCodecSerializer'));
   });
diff --git a/packages/pigeon/test/dart_generator_test.dart b/packages/pigeon/test/dart_generator_test.dart
index bf359ddfe43..c77e5d89e37 100644
--- a/packages/pigeon/test/dart_generator_test.dart
+++ b/packages/pigeon/test/dart_generator_test.dart
@@ -29,7 +29,7 @@ void main() {
       enums: <Enum>[],
     );
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(), root, sink);
+    generateDart(DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('class Foobar'));
     expect(code, contains('  dataType1? field1;'));
@@ -49,7 +49,7 @@ void main() {
       enums: <Enum>[anEnum],
     );
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(), root, sink);
+    generateDart(DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('enum Foobar'));
     expect(code, contains('  one,'));
@@ -92,7 +92,7 @@ void main() {
       ])
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(), root, sink);
+    generateDart(DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('class Api'));
     expect(code, contains('Future<Output> doSomething(Input arg_input)'));
@@ -118,7 +118,7 @@ void main() {
       ])
     ], classes: <Class>[], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(), root, sink);
+    generateDart(DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('class Api'));
     expect(code, contains('Future<int> add(int arg_x, int arg_y)'));
@@ -145,7 +145,7 @@ void main() {
       ])
     ], classes: <Class>[], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(), root, sink);
+    generateDart(DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('class Api'));
     expect(code, contains('int add(int x, int y)'));
@@ -182,7 +182,7 @@ void main() {
       )
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(), root, sink);
+    generateDart(DartOptions(), root, sink);
     final String code = sink.toString();
     expect(
       code,
@@ -224,7 +224,7 @@ void main() {
       )
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(), root, sink);
+    generateDart(DartOptions(), root, sink);
     final String code = sink.toString();
     expect(
       code,
@@ -276,7 +276,7 @@ void main() {
       ])
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(), root, sink);
+    generateDart(DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('abstract class Api'));
     expect(code, contains('static void setup(Api'));
@@ -310,7 +310,7 @@ void main() {
       ]),
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(), root, sink);
+    generateDart(DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('Future<void> doSomething'));
     expect(code, contains('return;'));
@@ -343,7 +343,7 @@ void main() {
       ]),
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(), root, sink);
+    generateDart(DartOptions(), root, sink);
     final String code = sink.toString();
     // The next line verifies that we're not setting a variable to the value of "doSomething", but
     // ignores the line where we assert the value of the argument isn't null, since on that line
@@ -373,7 +373,7 @@ void main() {
       ]),
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(), root, sink);
+    generateDart(DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, matches('output.*=.*doSomething[(][)]'));
     expect(code, contains('Output doSomething();'));
@@ -415,7 +415,7 @@ void main() {
       )
     ]);
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(), root, sink);
+    generateDart(DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('enum1?.index,'));
     expect(code, contains('? Enum.values[result[0]! as int]'));
@@ -442,7 +442,7 @@ void main() {
       ])
     ]);
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(), root, sink);
+    generateDart(DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('enum Foo {'));
     expect(code, contains('Future<void> bar(Foo? arg_foo) async'));
@@ -485,7 +485,7 @@ void main() {
       )
     ]);
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(), root, sink);
+    generateDart(DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('enum1.index,'));
     expect(code, contains('enum1: Enum.values[result[0]! as int]'));
@@ -512,7 +512,7 @@ void main() {
       ]),
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(), root, sink);
+    generateDart(DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, matches('channel.send[(]null[)]'));
   });
@@ -570,7 +570,7 @@ void main() {
     ], enums: <Enum>[]);
     final StringBuffer mainCodeSink = StringBuffer();
     final StringBuffer testCodeSink = StringBuffer();
-    generateDart(const DartOptions(), root, mainCodeSink);
+    generateDart(DartOptions(), root, mainCodeSink);
     final String mainCode = mainCodeSink.toString();
     expect(mainCode, isNot(contains(r"import 'fo\'o.dart';")));
     expect(mainCode, contains('class Api {'));
@@ -579,10 +579,10 @@ void main() {
     expect(mainCode, isNot(contains("'${Keys.result}': output")));
     expect(mainCode, isNot(contains('return <Object>[];')));
     generateTestDart(
-      const DartOptions(),
+      DartOptions(),
       root,
       testCodeSink,
-      dartOutPath: "fo'o.dart",
+      sourceOutPath: "fo'o.dart",
       testOutPath: 'test.dart',
     );
     final String testCode = testCodeSink.toString();
@@ -631,7 +631,7 @@ void main() {
       ])
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(), root, sink);
+    generateDart(DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('abstract class Api'));
     expect(code, contains('Future<Output> doSomething(Input arg0);'));
@@ -675,7 +675,7 @@ void main() {
       ])
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(), root, sink);
+    generateDart(DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, isNot(matches('=.s*doSomething')));
     expect(code, contains('await api.doSomething('));
@@ -719,7 +719,7 @@ void main() {
       ])
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(), root, sink);
+    generateDart(DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('class Api'));
     expect(code, matches('Output.*doSomething.*Input'));
@@ -747,7 +747,7 @@ void main() {
       ]),
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(), root, sink);
+    generateDart(DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, matches('channel.send[(]null[)]'));
   });
@@ -788,7 +788,7 @@ void main() {
       enums: <Enum>[],
     );
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(), root, sink);
+    generateDart(DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('class Foobar'));
     expect(code, contains('  List<int?>? field1;'));
@@ -815,7 +815,7 @@ void main() {
       enums: <Enum>[],
     );
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(), root, sink);
+    generateDart(DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('class Foobar'));
     expect(code, contains('  Map<String?, int?>? field1;'));
@@ -844,7 +844,7 @@ void main() {
       enums: <Enum>[],
     );
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(), root, sink);
+    generateDart(DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('doit(List<int?> arg'));
   });
@@ -872,7 +872,7 @@ void main() {
       enums: <Enum>[],
     );
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(), root, sink);
+    generateDart(DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('doit(List<int?> arg'));
   });
@@ -896,7 +896,7 @@ void main() {
       enums: <Enum>[],
     );
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(), root, sink);
+    generateDart(DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('Future<List<int?>> doit('));
     expect(code,
@@ -931,7 +931,7 @@ void main() {
       enums: <Enum>[],
     );
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(), root, sink);
+    generateDart(DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('List<int?> doit('));
     expect(
@@ -958,7 +958,7 @@ void main() {
       enums: <Enum>[],
     );
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(), root, sink);
+    generateDart(DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('Future<int?> doit()'));
     expect(code, contains('return (replyList[0] as int?);'));
@@ -983,7 +983,7 @@ void main() {
       enums: <Enum>[],
     );
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(), root, sink);
+    generateDart(DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('Future<List<int?>?> doit()'));
     expect(code,
@@ -1008,7 +1008,7 @@ void main() {
       enums: <Enum>[],
     );
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(), root, sink);
+    generateDart(DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('Future<int?> doit()'));
     expect(code, contains('return (replyList[0] as int?);'));
@@ -1031,7 +1031,7 @@ void main() {
       enums: <Enum>[],
     );
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(), root, sink);
+    generateDart(DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('int? doit();'));
     expect(code, contains('final int? output = api.doit();'));
@@ -1055,7 +1055,7 @@ void main() {
       enums: <Enum>[],
     );
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(), root, sink);
+    generateDart(DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('Future<int?> doit();'));
     expect(code, contains('final int? output = await api.doit();'));
@@ -1078,7 +1078,7 @@ void main() {
       enums: <Enum>[],
     );
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(), root, sink);
+    generateDart(DartOptions(), root, sink);
     final String code = sink.toString();
     expect(
         code,
@@ -1107,7 +1107,7 @@ void main() {
       enums: <Enum>[],
     );
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(), root, sink);
+    generateDart(DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('Future<void> doit(int? arg_foo) async {'));
   });
@@ -1133,7 +1133,7 @@ void main() {
       enums: <Enum>[],
     );
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(), root, sink);
+    generateDart(DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('void doit(int? foo);'));
   });
@@ -1151,10 +1151,10 @@ name: foobar
           Root(classes: <Class>[], apis: <Api>[], enums: <Enum>[]);
       final StringBuffer sink = StringBuffer();
       generateTestDart(
-        const DartOptions(),
+        DartOptions(),
         root,
         sink,
-        dartOutPath: path.join(foo.path, 'bar.dart'),
+        sourceOutPath: path.join(foo.path, 'bar.dart'),
         testOutPath: path.join(tempDir.path, 'test', 'bar_test.dart'),
       );
       final String code = sink.toString();
@@ -1238,7 +1238,7 @@ name: foobar
       ],
     );
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(), root, sink);
+    generateDart(DartOptions(), root, sink);
     final String code = sink.toString();
     for (final String comment in comments) {
       expect(code, contains('///$comment'));
@@ -1273,7 +1273,7 @@ name: foobar
       enums: <Enum>[],
     );
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(), root, sink);
+    generateDart(DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, isNot(contains('extends StandardMessageCodec')));
     expect(code, contains('StandardMessageCodec'));
@@ -1316,7 +1316,7 @@ name: foobar
       ])
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(), root, sink);
+    generateDart(DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('extends StandardMessageCodec'));
   });
@@ -1355,10 +1355,10 @@ name: foobar
     );
     final StringBuffer sink = StringBuffer();
     generateTestDart(
-      const DartOptions(),
+      DartOptions(),
       root,
       sink,
-      dartOutPath: 'code.dart',
+      sourceOutPath: 'code.dart',
       testOutPath: 'test.dart',
     );
     final String testCode = sink.toString();
diff --git a/packages/pigeon/test/objc_generator_test.dart b/packages/pigeon/test/objc_generator_test.dart
index cf83029338e..aeb2db68e26 100644
--- a/packages/pigeon/test/objc_generator_test.dart
+++ b/packages/pigeon/test/objc_generator_test.dart
@@ -32,7 +32,8 @@ void main() {
       ]),
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
-    generateObjcSource(const ObjcOptions(header: 'foo.h'), root, sink);
+    generateObjcSource(
+        const ObjcOptions(headerIncludePath: 'foo.h'), root, sink);
     final String code = sink.toString();
     expect(code, contains('#import "foo.h"'));
     expect(code, contains('@implementation Foobar'));
@@ -103,7 +104,8 @@ void main() {
       ],
     );
     final StringBuffer sink = StringBuffer();
-    generateObjcSource(const ObjcOptions(header: 'foo.h'), root, sink);
+    generateObjcSource(
+        const ObjcOptions(headerIncludePath: 'foo.h'), root, sink);
     final String code = sink.toString();
     expect(code, contains('#import "foo.h"'));
     expect(code, contains('@implementation Foobar'));
@@ -133,7 +135,8 @@ void main() {
       ])
     ]);
     final StringBuffer sink = StringBuffer();
-    const ObjcOptions options = ObjcOptions(header: 'foo.h', prefix: 'AC');
+    const ObjcOptions options =
+        ObjcOptions(headerIncludePath: 'foo.h', prefix: 'AC');
     {
       generateObjcHeader(options, root, sink);
       final String code = sink.toString();
@@ -169,7 +172,7 @@ void main() {
         EnumMember(name: 'two'),
       ])
     ]);
-    const ObjcOptions options = ObjcOptions(header: 'foo.h');
+    const ObjcOptions options = ObjcOptions(headerIncludePath: 'foo.h');
     final List<Error> errors = validateObjc(options, root);
     expect(errors.length, 1);
     expect(errors[0].message, contains('Nullable enum'));
@@ -204,7 +207,8 @@ void main() {
       ],
     );
     final StringBuffer sink = StringBuffer();
-    generateObjcHeader(const ObjcOptions(header: 'foo.h'), root, sink);
+    generateObjcHeader(
+        const ObjcOptions(headerIncludePath: 'foo.h'), root, sink);
     final String code = sink.toString();
     expect(code, contains('@property(nonatomic, assign) Enum1 enum1'));
   });
@@ -275,7 +279,8 @@ void main() {
       ])
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
-    generateObjcSource(const ObjcOptions(header: 'foo.h'), root, sink);
+    generateObjcSource(
+        const ObjcOptions(headerIncludePath: 'foo.h'), root, sink);
     final String code = sink.toString();
     expect(code, contains('#import "foo.h"'));
     expect(code, contains('@implementation Input'));
@@ -322,7 +327,8 @@ void main() {
     ], enums: <Enum>[]);
 
     final StringBuffer sink = StringBuffer();
-    generateObjcHeader(const ObjcOptions(header: 'foo.h'), root, sink);
+    generateObjcHeader(
+        const ObjcOptions(headerIncludePath: 'foo.h'), root, sink);
     final String code = sink.toString();
     expect(code, contains('@interface Foobar'));
     expect(code, contains('@class FlutterStandardTypedData;'));
@@ -350,7 +356,8 @@ void main() {
     ], enums: <Enum>[]);
 
     final StringBuffer sink = StringBuffer();
-    generateObjcSource(const ObjcOptions(header: 'foo.h'), root, sink);
+    generateObjcSource(
+        const ObjcOptions(headerIncludePath: 'foo.h'), root, sink);
     final String code = sink.toString();
     expect(code, contains('@implementation Foobar'));
     expect(code,
@@ -371,7 +378,8 @@ void main() {
       ])
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
-    generateObjcHeader(const ObjcOptions(header: 'foo.h'), root, sink);
+    generateObjcHeader(
+        const ObjcOptions(headerIncludePath: 'foo.h'), root, sink);
     final String code = sink.toString();
     expect(code,
         contains('@property(nonatomic, strong, nullable) Input * nested;'));
@@ -391,7 +399,8 @@ void main() {
       ])
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
-    generateObjcSource(const ObjcOptions(header: 'foo.h'), root, sink);
+    generateObjcSource(
+        const ObjcOptions(headerIncludePath: 'foo.h'), root, sink);
     final String code = sink.toString();
     expect(
         code,
@@ -530,7 +539,8 @@ void main() {
       ])
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
-    generateObjcHeader(const ObjcOptions(header: 'foo.h'), root, sink);
+    generateObjcHeader(
+        const ObjcOptions(headerIncludePath: 'foo.h'), root, sink);
     final String code = sink.toString();
     expect(code, contains('@interface Api : NSObject'));
     expect(
@@ -569,7 +579,8 @@ void main() {
       ])
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
-    generateObjcSource(const ObjcOptions(header: 'foo.h'), root, sink);
+    generateObjcSource(
+        const ObjcOptions(headerIncludePath: 'foo.h'), root, sink);
     final String code = sink.toString();
     expect(code, contains('@implementation Api'));
     expect(code, matches('void.*doSomething.*Input.*Output.*{'));
@@ -599,7 +610,9 @@ void main() {
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
     generateObjcHeader(
-        const ObjcOptions(header: 'foo.h', prefix: 'ABC'), root, sink);
+        const ObjcOptions(headerIncludePath: 'foo.h', prefix: 'ABC'),
+        root,
+        sink);
     final String code = sink.toString();
     expect(code, contains('(void)doSomething:'));
   });
@@ -628,7 +641,9 @@ void main() {
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
     generateObjcSource(
-        const ObjcOptions(header: 'foo.h', prefix: 'ABC'), root, sink);
+        const ObjcOptions(headerIncludePath: 'foo.h', prefix: 'ABC'),
+        root,
+        sink);
     final String code = sink.toString();
     expect(code, isNot(matches('=.*doSomething')));
     expect(code, matches('[.*doSomething:.*]'));
@@ -659,7 +674,9 @@ void main() {
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
     generateObjcHeader(
-        const ObjcOptions(header: 'foo.h', prefix: 'ABC'), root, sink);
+        const ObjcOptions(headerIncludePath: 'foo.h', prefix: 'ABC'),
+        root,
+        sink);
     final String code = sink.toString();
     expect(code, contains('completion:(void(^)(NSError *_Nullable))'));
   });
@@ -688,7 +705,9 @@ void main() {
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
     generateObjcSource(
-        const ObjcOptions(header: 'foo.h', prefix: 'ABC'), root, sink);
+        const ObjcOptions(headerIncludePath: 'foo.h', prefix: 'ABC'),
+        root,
+        sink);
     final String code = sink.toString();
     expect(code, contains('completion:(void(^)(NSError *_Nullable))'));
     expect(code, contains('completion(nil)'));
@@ -712,7 +731,9 @@ void main() {
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
     generateObjcHeader(
-        const ObjcOptions(header: 'foo.h', prefix: 'ABC'), root, sink);
+        const ObjcOptions(headerIncludePath: 'foo.h', prefix: 'ABC'),
+        root,
+        sink);
     final String code = sink.toString();
     expect(code, matches('ABCOutput.*doSomethingWithError:[(]FlutterError'));
   });
@@ -735,7 +756,9 @@ void main() {
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
     generateObjcSource(
-        const ObjcOptions(header: 'foo.h', prefix: 'ABC'), root, sink);
+        const ObjcOptions(headerIncludePath: 'foo.h', prefix: 'ABC'),
+        root,
+        sink);
     final String code = sink.toString();
     expect(code, matches('output.*=.*api doSomethingWithError:&error'));
   });
@@ -758,7 +781,9 @@ void main() {
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
     generateObjcHeader(
-        const ObjcOptions(header: 'foo.h', prefix: 'ABC'), root, sink);
+        const ObjcOptions(headerIncludePath: 'foo.h', prefix: 'ABC'),
+        root,
+        sink);
     final String code = sink.toString();
     expect(
         code,
@@ -784,7 +809,9 @@ void main() {
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
     generateObjcSource(
-        const ObjcOptions(header: 'foo.h', prefix: 'ABC'), root, sink);
+        const ObjcOptions(headerIncludePath: 'foo.h', prefix: 'ABC'),
+        root,
+        sink);
     final String code = sink.toString();
     expect(
         code,
@@ -902,7 +929,9 @@ void main() {
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
     generateObjcHeader(
-        const ObjcOptions(header: 'foo.h', prefix: 'ABC'), root, sink);
+        const ObjcOptions(headerIncludePath: 'foo.h', prefix: 'ABC'),
+        root,
+        sink);
     final String code = sink.toString();
     expect(
         code,
@@ -941,7 +970,9 @@ void main() {
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
     generateObjcHeader(
-        const ObjcOptions(header: 'foo.h', prefix: 'ABC'), root, sink);
+        const ObjcOptions(headerIncludePath: 'foo.h', prefix: 'ABC'),
+        root,
+        sink);
     final String code = sink.toString();
     expect(
         code,
@@ -968,7 +999,9 @@ void main() {
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
     generateObjcHeader(
-        const ObjcOptions(header: 'foo.h', prefix: 'ABC'), root, sink);
+        const ObjcOptions(headerIncludePath: 'foo.h', prefix: 'ABC'),
+        root,
+        sink);
     final String code = sink.toString();
     expect(
         code,
@@ -988,7 +1021,9 @@ void main() {
     ], classes: <Class>[], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
     generateObjcHeader(
-        const ObjcOptions(header: 'foo.h', prefix: 'ABC'), root, sink);
+        const ObjcOptions(headerIncludePath: 'foo.h', prefix: 'ABC'),
+        root,
+        sink);
     final String code = sink.toString();
     expect(
         code,
@@ -1027,7 +1062,9 @@ void main() {
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
     generateObjcSource(
-        const ObjcOptions(header: 'foo.h', prefix: 'ABC'), root, sink);
+        const ObjcOptions(headerIncludePath: 'foo.h', prefix: 'ABC'),
+        root,
+        sink);
     final String code = sink.toString();
     expect(
         code,
@@ -1065,7 +1102,9 @@ void main() {
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
     generateObjcSource(
-        const ObjcOptions(header: 'foo.h', prefix: 'ABC'), root, sink);
+        const ObjcOptions(headerIncludePath: 'foo.h', prefix: 'ABC'),
+        root,
+        sink);
     final String code = sink.toString();
     expect(
         code,
@@ -1085,7 +1124,9 @@ void main() {
     ], classes: <Class>[], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
     generateObjcSource(
-        const ObjcOptions(header: 'foo.h', prefix: 'ABC'), root, sink);
+        const ObjcOptions(headerIncludePath: 'foo.h', prefix: 'ABC'),
+        root,
+        sink);
     final String code = sink.toString();
     expect(
         code,
@@ -1112,7 +1153,9 @@ void main() {
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
     generateObjcSource(
-        const ObjcOptions(header: 'foo.h', prefix: 'ABC'), root, sink);
+        const ObjcOptions(headerIncludePath: 'foo.h', prefix: 'ABC'),
+        root,
+        sink);
     final String code = sink.toString();
     expect(
         code,
@@ -1129,7 +1172,7 @@ void main() {
     final StringBuffer sink = StringBuffer();
     generateObjcSource(
       ObjcOptions(
-          header: 'foo.h',
+          headerIncludePath: 'foo.h',
           prefix: 'ABC',
           copyrightHeader: makeIterable('hello world')),
       root,
@@ -1144,7 +1187,7 @@ void main() {
     final StringBuffer sink = StringBuffer();
     generateObjcHeader(
       ObjcOptions(
-          header: 'foo.h',
+          headerIncludePath: 'foo.h',
           prefix: 'ABC',
           copyrightHeader: makeIterable('hello world')),
       root,
@@ -1175,7 +1218,9 @@ void main() {
     );
     final StringBuffer sink = StringBuffer();
     generateObjcHeader(
-        const ObjcOptions(header: 'foo.h', prefix: 'ABC'), root, sink);
+        const ObjcOptions(headerIncludePath: 'foo.h', prefix: 'ABC'),
+        root,
+        sink);
     final String code = sink.toString();
     expect(code, contains('NSArray<NSNumber *> * field1'));
   });
@@ -1205,14 +1250,18 @@ void main() {
     {
       final StringBuffer sink = StringBuffer();
       generateObjcHeader(
-          const ObjcOptions(header: 'foo.h', prefix: 'ABC'), root, sink);
+          const ObjcOptions(headerIncludePath: 'foo.h', prefix: 'ABC'),
+          root,
+          sink);
       final String code = sink.toString();
       expect(code, contains('doitArg:(NSArray<NSNumber *> *)arg'));
     }
     {
       final StringBuffer sink = StringBuffer();
       generateObjcSource(
-          const ObjcOptions(header: 'foo.h', prefix: 'ABC'), root, sink);
+          const ObjcOptions(headerIncludePath: 'foo.h', prefix: 'ABC'),
+          root,
+          sink);
       final String code = sink.toString();
       expect(
           code,
@@ -1246,14 +1295,18 @@ void main() {
     {
       final StringBuffer sink = StringBuffer();
       generateObjcHeader(
-          const ObjcOptions(header: 'foo.h', prefix: 'ABC'), root, sink);
+          const ObjcOptions(headerIncludePath: 'foo.h', prefix: 'ABC'),
+          root,
+          sink);
       final String code = sink.toString();
       expect(code, contains('doitArg:(NSArray<NSNumber *> *)arg'));
     }
     {
       final StringBuffer sink = StringBuffer();
       generateObjcSource(
-          const ObjcOptions(header: 'foo.h', prefix: 'ABC'), root, sink);
+          const ObjcOptions(headerIncludePath: 'foo.h', prefix: 'ABC'),
+          root,
+          sink);
       final String code = sink.toString();
       expect(code, contains('doitArg:(NSArray<NSNumber *> *)arg'));
     }
@@ -1290,7 +1343,9 @@ void main() {
     {
       final StringBuffer sink = StringBuffer();
       generateObjcHeader(
-          const ObjcOptions(header: 'foo.h', prefix: 'ABC'), root, sink);
+          const ObjcOptions(headerIncludePath: 'foo.h', prefix: 'ABC'),
+          root,
+          sink);
       final String code = sink.toString();
       expect(code, contains('doitArg:(NSArray<NSArray<NSNumber *> *> *)arg'));
     }
@@ -1317,7 +1372,9 @@ void main() {
     {
       final StringBuffer sink = StringBuffer();
       generateObjcHeader(
-          const ObjcOptions(header: 'foo.h', prefix: 'ABC'), root, sink);
+          const ObjcOptions(headerIncludePath: 'foo.h', prefix: 'ABC'),
+          root,
+          sink);
       final String code = sink.toString();
       expect(
           code, contains('- (nullable NSArray<NSNumber *> *)doitWithError:'));
@@ -1325,7 +1382,9 @@ void main() {
     {
       final StringBuffer sink = StringBuffer();
       generateObjcSource(
-          const ObjcOptions(header: 'foo.h', prefix: 'ABC'), root, sink);
+          const ObjcOptions(headerIncludePath: 'foo.h', prefix: 'ABC'),
+          root,
+          sink);
       final String code = sink.toString();
       expect(code, contains('NSArray<NSNumber *> *output ='));
     }
@@ -1352,7 +1411,9 @@ void main() {
     {
       final StringBuffer sink = StringBuffer();
       generateObjcHeader(
-          const ObjcOptions(header: 'foo.h', prefix: 'ABC'), root, sink);
+          const ObjcOptions(headerIncludePath: 'foo.h', prefix: 'ABC'),
+          root,
+          sink);
       final String code = sink.toString();
       expect(
           code, contains('doitWithCompletion:(void(^)(NSArray<NSNumber *> *'));
@@ -1360,7 +1421,9 @@ void main() {
     {
       final StringBuffer sink = StringBuffer();
       generateObjcSource(
-          const ObjcOptions(header: 'foo.h', prefix: 'ABC'), root, sink);
+          const ObjcOptions(headerIncludePath: 'foo.h', prefix: 'ABC'),
+          root,
+          sink);
       final String code = sink.toString();
       expect(
           code, contains('doitWithCompletion:(void(^)(NSArray<NSNumber *> *'));
@@ -1389,7 +1452,9 @@ void main() {
     {
       final StringBuffer sink = StringBuffer();
       generateObjcHeader(
-          const ObjcOptions(header: 'foo.h', prefix: 'ABC'), root, sink);
+          const ObjcOptions(headerIncludePath: 'foo.h', prefix: 'ABC'),
+          root,
+          sink);
       final String code = sink.toString();
       expect(
           code,
@@ -1399,7 +1464,9 @@ void main() {
     {
       final StringBuffer sink = StringBuffer();
       generateObjcSource(
-          const ObjcOptions(header: 'foo.h', prefix: 'ABC'), root, sink);
+          const ObjcOptions(headerIncludePath: 'foo.h', prefix: 'ABC'),
+          root,
+          sink);
       final String code = sink.toString();
       expect(code, contains('NSArray *args = message;'));
       expect(code,
@@ -1434,7 +1501,9 @@ void main() {
     {
       final StringBuffer sink = StringBuffer();
       generateObjcHeader(
-          const ObjcOptions(header: 'foo.h', prefix: 'ABC'), root, sink);
+          const ObjcOptions(headerIncludePath: 'foo.h', prefix: 'ABC'),
+          root,
+          sink);
       final String code = sink.toString();
       expect(
           code,
@@ -1444,7 +1513,9 @@ void main() {
     {
       final StringBuffer sink = StringBuffer();
       generateObjcSource(
-          const ObjcOptions(header: 'foo.h', prefix: 'ABC'), root, sink);
+          const ObjcOptions(headerIncludePath: 'foo.h', prefix: 'ABC'),
+          root,
+          sink);
       final String code = sink.toString();
       expect(code, contains('NSArray *args = message;'));
       expect(code,
@@ -1477,7 +1548,9 @@ void main() {
     {
       final StringBuffer sink = StringBuffer();
       generateObjcHeader(
-          const ObjcOptions(header: 'foo.h', prefix: 'ABC'), root, sink);
+          const ObjcOptions(headerIncludePath: 'foo.h', prefix: 'ABC'),
+          root,
+          sink);
       final String code = sink.toString();
       expect(
           code,
@@ -1487,7 +1560,9 @@ void main() {
     {
       final StringBuffer sink = StringBuffer();
       generateObjcSource(
-          const ObjcOptions(header: 'foo.h', prefix: 'ABC'), root, sink);
+          const ObjcOptions(headerIncludePath: 'foo.h', prefix: 'ABC'),
+          root,
+          sink);
       final String code = sink.toString();
       expect(
           code,
@@ -1531,14 +1606,18 @@ void main() {
     {
       final StringBuffer sink = StringBuffer();
       generateObjcHeader(
-          const ObjcOptions(header: 'foo.h', prefix: 'ABC'), divideRoot, sink);
+          const ObjcOptions(headerIncludePath: 'foo.h', prefix: 'ABC'),
+          divideRoot,
+          sink);
       final String code = sink.toString();
       expect(code, matches('divideValue:.*by:.*error.*;'));
     }
     {
       final StringBuffer sink = StringBuffer();
       generateObjcSource(
-          const ObjcOptions(header: 'foo.h', prefix: 'ABC'), divideRoot, sink);
+          const ObjcOptions(headerIncludePath: 'foo.h', prefix: 'ABC'),
+          divideRoot,
+          sink);
       final String code = sink.toString();
       expect(code, matches('divideValue:.*by:.*error.*;'));
     }
@@ -1549,7 +1628,7 @@ void main() {
     {
       final StringBuffer sink = StringBuffer();
       generateObjcHeader(
-        const ObjcOptions(header: 'foo.h', prefix: 'ABC'),
+        const ObjcOptions(headerIncludePath: 'foo.h', prefix: 'ABC'),
         divideRoot,
         sink,
       );
@@ -1559,7 +1638,7 @@ void main() {
     {
       final StringBuffer sink = StringBuffer();
       generateObjcSource(
-        const ObjcOptions(header: 'foo.h', prefix: 'ABC'),
+        const ObjcOptions(headerIncludePath: 'foo.h', prefix: 'ABC'),
         divideRoot,
         sink,
       );
diff --git a/packages/pigeon/test/pigeon_lib_test.dart b/packages/pigeon/test/pigeon_lib_test.dart
index 4a121e7e9e0..64c4af7b5ab 100644
--- a/packages/pigeon/test/pigeon_lib_test.dart
+++ b/packages/pigeon/test/pigeon_lib_test.dart
@@ -6,20 +6,26 @@ import 'dart:async';
 import 'dart:io';
 
 import 'package:pigeon/ast.dart';
+import 'package:pigeon/generator_tools.dart';
 import 'package:pigeon/pigeon_lib.dart';
 import 'package:test/test.dart';
 
-class _ValidatorGenerator implements Generator {
-  _ValidatorGenerator(this.sink);
+class _ValidatorGeneratorAdapter implements GeneratorAdapter {
+  _ValidatorGeneratorAdapter(this.sink);
+
+  @override
+  List<FileType> fileTypeList = const <FileType>[FileType.na];
+
   bool didCallValidate = false;
 
   final IOSink? sink;
 
   @override
-  void generate(StringSink sink, PigeonOptions options, Root root) {}
+  void generate(
+      StringSink sink, PigeonOptions options, Root root, FileType fileType) {}
 
   @override
-  IOSink? shouldGenerate(PigeonOptions options) => sink;
+  IOSink? shouldGenerate(PigeonOptions options, FileType _) => sink;
 
   @override
   List<Error> validate(PigeonOptions options, Root root) {
@@ -397,9 +403,9 @@ abstract class NestorApi {
     final Root root = Root(apis: <Api>[], classes: <Class>[], enums: <Enum>[]);
     const PigeonOptions options =
         PigeonOptions(copyrightHeader: './copyright_header.txt');
-    const DartGenerator dartGenerator = DartGenerator();
+    final DartGeneratorAdapter dartGeneratorAdapter = DartGeneratorAdapter();
     final StringBuffer buffer = StringBuffer();
-    dartGenerator.generate(buffer, options, root);
+    dartGeneratorAdapter.generate(buffer, options, root, FileType.na);
     expect(buffer.toString(), startsWith('// Copyright 2013'));
   });
 
@@ -407,9 +413,9 @@ abstract class NestorApi {
     final Root root = Root(apis: <Api>[], classes: <Class>[], enums: <Enum>[]);
     const PigeonOptions options = PigeonOptions(
         javaOut: 'Foo.java', copyrightHeader: './copyright_header.txt');
-    const JavaGenerator javaGenerator = JavaGenerator();
+    final JavaGeneratorAdapter javaGeneratorAdapter = JavaGeneratorAdapter();
     final StringBuffer buffer = StringBuffer();
-    javaGenerator.generate(buffer, options, root);
+    javaGeneratorAdapter.generate(buffer, options, root, FileType.na);
     expect(buffer.toString(), startsWith('// Copyright 2013'));
   });
 
@@ -417,9 +423,10 @@ abstract class NestorApi {
     final Root root = Root(apis: <Api>[], classes: <Class>[], enums: <Enum>[]);
     const PigeonOptions options =
         PigeonOptions(copyrightHeader: './copyright_header.txt');
-    const ObjcHeaderGenerator objcHeaderGenerator = ObjcHeaderGenerator();
+    final ObjcGeneratorAdapter objcHeaderGeneratorAdapter =
+        ObjcGeneratorAdapter();
     final StringBuffer buffer = StringBuffer();
-    objcHeaderGenerator.generate(buffer, options, root);
+    objcHeaderGeneratorAdapter.generate(buffer, options, root, FileType.header);
     expect(buffer.toString(), startsWith('// Copyright 2013'));
   });
 
@@ -427,9 +434,10 @@ abstract class NestorApi {
     final Root root = Root(apis: <Api>[], classes: <Class>[], enums: <Enum>[]);
     const PigeonOptions options =
         PigeonOptions(copyrightHeader: './copyright_header.txt');
-    const ObjcSourceGenerator objcSourceGenerator = ObjcSourceGenerator();
+    final ObjcGeneratorAdapter objcSourceGeneratorAdapter =
+        ObjcGeneratorAdapter();
     final StringBuffer buffer = StringBuffer();
-    objcSourceGenerator.generate(buffer, options, root);
+    objcSourceGeneratorAdapter.generate(buffer, options, root, FileType.source);
     expect(buffer.toString(), startsWith('// Copyright 2013'));
   });
 
@@ -437,9 +445,9 @@ abstract class NestorApi {
     final Root root = Root(apis: <Api>[], classes: <Class>[], enums: <Enum>[]);
     const PigeonOptions options = PigeonOptions(
         swiftOut: 'Foo.swift', copyrightHeader: './copyright_header.txt');
-    const SwiftGenerator swiftGenerator = SwiftGenerator();
+    final SwiftGeneratorAdapter swiftGeneratorAdapter = SwiftGeneratorAdapter();
     final StringBuffer buffer = StringBuffer();
-    swiftGenerator.generate(buffer, options, root);
+    swiftGeneratorAdapter.generate(buffer, options, root, FileType.na);
     expect(buffer.toString(), startsWith('// Copyright 2013'));
   });
 
@@ -447,9 +455,9 @@ abstract class NestorApi {
     final Root root = Root(apis: <Api>[], classes: <Class>[], enums: <Enum>[]);
     const PigeonOptions options = PigeonOptions(
         cppHeaderOut: 'Foo.h', copyrightHeader: './copyright_header.txt');
-    const CppHeaderGenerator cppHeaderGenerator = CppHeaderGenerator();
+    final CppGeneratorAdapter cppHeaderGeneratorAdapter = CppGeneratorAdapter();
     final StringBuffer buffer = StringBuffer();
-    cppHeaderGenerator.generate(buffer, options, root);
+    cppHeaderGeneratorAdapter.generate(buffer, options, root, FileType.header);
     expect(buffer.toString(), startsWith('// Copyright 2013'));
   });
 
@@ -457,9 +465,10 @@ abstract class NestorApi {
     final Root root = Root(apis: <Api>[], classes: <Class>[], enums: <Enum>[]);
     const PigeonOptions options =
         PigeonOptions(copyrightHeader: './copyright_header.txt');
-    const CppSourceGenerator cppSourceGenerator = CppSourceGenerator();
+    final CppGeneratorAdapter cppSourceGeneratorAdapter =
+        CppGeneratorAdapter(fileTypeList: <FileType>[FileType.source]);
     final StringBuffer buffer = StringBuffer();
-    cppSourceGenerator.generate(buffer, options, root);
+    cppSourceGeneratorAdapter.generate(buffer, options, root, FileType.source);
     expect(buffer.toString(), startsWith('// Copyright 2013'));
   });
 
@@ -929,9 +938,10 @@ abstract class Api {
       dartTestOut: 'stdout',
       dartOut: 'stdout',
     );
-    const DartTestGenerator dartGenerator = DartTestGenerator();
+    final DartTestGeneratorAdapter dartGeneratorAdapter =
+        DartTestGeneratorAdapter();
     final StringBuffer buffer = StringBuffer();
-    dartGenerator.generate(buffer, options, root);
+    dartGeneratorAdapter.generate(buffer, options, root, FileType.source);
     expect(buffer.toString(), startsWith('// Copyright 2013'));
   });
 
@@ -1187,9 +1197,10 @@ abstract class Api {
   test('generator validation', () async {
     final Completer<void> completer = Completer<void>();
     withTempFile('foo.dart', (File input) async {
-      final _ValidatorGenerator generator = _ValidatorGenerator(stdout);
+      final _ValidatorGeneratorAdapter generator =
+          _ValidatorGeneratorAdapter(stdout);
       final int result = await Pigeon.run(<String>['--input', input.path],
-          generators: <Generator>[generator]);
+          adapters: <GeneratorAdapter>[generator]);
       expect(generator.didCallValidate, isTrue);
       expect(result, isNot(0));
       completer.complete();
@@ -1200,10 +1211,11 @@ abstract class Api {
   test('generator validation skipped', () async {
     final Completer<void> completer = Completer<void>();
     withTempFile('foo.dart', (File input) async {
-      final _ValidatorGenerator generator = _ValidatorGenerator(null);
+      final _ValidatorGeneratorAdapter generator =
+          _ValidatorGeneratorAdapter(null);
       final int result = await Pigeon.run(
           <String>['--input', input.path, '--dart_out', 'foo.dart'],
-          generators: <Generator>[generator]);
+          adapters: <GeneratorAdapter>[generator]);
       expect(generator.didCallValidate, isFalse);
       expect(result, equals(0));
       completer.complete();
@@ -1214,10 +1226,11 @@ abstract class Api {
   test('run with PigeonOptions', () async {
     final Completer<void> completer = Completer<void>();
     withTempFile('foo.dart', (File input) async {
-      final _ValidatorGenerator generator = _ValidatorGenerator(null);
+      final _ValidatorGeneratorAdapter generator =
+          _ValidatorGeneratorAdapter(null);
       final int result = await Pigeon.runWithOptions(
           PigeonOptions(input: input.path, dartOut: 'foo.dart'),
-          generators: <Generator>[generator]);
+          adapters: <GeneratorAdapter>[generator]);
       expect(generator.didCallValidate, isFalse);
       expect(result, equals(0));
       completer.complete();
diff --git a/packages/pigeon/tool/shared/generation.dart b/packages/pigeon/tool/shared/generation.dart
index 01efa09c8f5..3e6ced166f8 100644
--- a/packages/pigeon/tool/shared/generation.dart
+++ b/packages/pigeon/tool/shared/generation.dart
@@ -168,7 +168,7 @@ Future<int> runPigeon({
     copyrightHeader: './copyright_header.txt',
     dartOut: dartOut,
     dartTestOut: dartTestOut,
-    dartOptions: const DartOptions(),
+    dartOptions: DartOptions(),
     cppHeaderOut: cppHeaderOut,
     cppSourceOut: cppSourceOut,
     cppOptions: CppOptions(namespace: cppNamespace),