[pigeon] Creates new Generator classes for each language (v3) (#3022)

* Rename generator class to Adapter

* create new generator class and dart subclass

* cpp and dart test gen

* added files

* Adds Generator class to all generators

* adds swift

* Updates tests to use new Adapter naming scheme

* Dart generate methods

* convert all generate functions to use new method

* chagngelog

* remove Generator class fields

* move paths to options

* remove dartTestOptions

* Nits and combines source and header generators

* renames Adapter to GeneratorAdapter

* Update version number for breaking changes

* nits

* more personal nits

* Fixes dart header bug

* add gen files for clarity

* better field naming

* better field naming

* removed unneeded dart test generator

* Add filetype to generator

* Adds filetype as field to generatorAdapters

* nits

* assert

* Default FileType

* alt v4

* alt v5

* nits

Author: tarrinneal

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.

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;
 
@@ -21,36 +22,41 @@ 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;
 
   /// 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?,
     );
   }
 
   /// Converts a [CppOptions] to a Map representation where:
   /// `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',

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.
@@ -24,18 +25,30 @@ 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) {
     final Iterable<dynamic>? copyrightHeader =
         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

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);
+}

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;
+}

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';
 

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';