[pigeon] migrate to null-safety

packages/pigeon/README.md

@@ -78,7 +78,7 @@ Example:
 
 ```dart
 class Value {
-  int number;
+  int? number;
 }
 
 @HostApi()

packages/pigeon/example/README.md

@@ -14,11 +14,11 @@ from Flutter to the host-platform.
 import 'package:pigeon/pigeon.dart';
 
 class SearchRequest {
-  String query;
+  String? query;
 }
 
 class SearchReply {
-  String result;
+  String? result;
 }
 
 @HostApi()

packages/pigeon/lib/ast.dart

@@ -17,8 +17,12 @@ class Node {}
 /// Represents a method on an [Api].
 class Method extends Node {
   /// Parametric constructor for [Method].
-  Method(
-      {this.name, this.returnType, this.argType, this.isAsynchronous = false});
+  Method({
+    required this.name,
+    required this.returnType,
+    required this.argType,
+    this.isAsynchronous = false,
+  });
 
   /// The name of the method.
   String name;
@@ -36,7 +40,12 @@ class Method extends Node {
 /// Represents a collection of [Method]s that are hosted on a given [location].
 class Api extends Node {
   /// Parametric constructor for [Api].
-  Api({this.name, this.location, this.methods, this.dartHostTestHandler});
+  Api({
+    required this.name,
+    required this.location,
+    required this.methods,
+    this.dartHostTestHandler,
+  });
 
   /// The name of the API.
   String name;
@@ -48,13 +57,16 @@ class Api extends Node {
   List<Method> methods;
 
   /// The name of the Dart test interface to generate to help with testing.
-  String dartHostTestHandler;
+  String? dartHostTestHandler;
 }
 
 /// Represents a field on a [Class].
 class Field extends Node {
   /// Parametric constructor for [Field].
-  Field({this.name, this.dataType});
+  Field({
+    required this.name,
+    required this.dataType,
+  });
 
   /// The name of the field.
   String name;
@@ -71,7 +83,10 @@ class Field extends Node {
 /// Represents a class with [Field]s.
 class Class extends Node {
   /// Parametric constructor for [Class].
-  Class({this.name, this.fields});
+  Class({
+    required this.name,
+    required this.fields,
+  });
 
   /// The name of the class.
   String name;
@@ -88,7 +103,10 @@ class Class extends Node {
 /// Top-level node for the AST.
 class Root extends Node {
   /// Parametric constructor for [Root].
-  Root({this.classes, this.apis});
+  Root({
+    required this.classes,
+    required this.apis,
+  });
 
   /// All the classes contained in the AST.
   List<Class> classes;

packages/pigeon/lib/dart_generator.dart

@@ -33,7 +33,7 @@ void _writeHostApi(DartOptions opt, Indent indent, Api api) {
       }
       String argSignature = '';
       String sendArgument = 'null';
-      String encodedDeclaration;
+      String? encodedDeclaration;
       if (func.argType != 'void') {
         argSignature = '${func.argType} arg';
         sendArgument = 'encoded';
@@ -47,17 +47,18 @@ void _writeHostApi(DartOptions opt, Indent indent, Api api) {
           indent.writeln(encodedDeclaration);
         }
         final String channelName = makeChannelName(api, func);
-        indent.writeln('const BasicMessageChannel<Object$nullTag> channel =');
+        indent.writeln(
+            'const BasicMessageChannel<Object$nullTag> channel = BasicMessageChannel<Object$nullTag>(');
         indent.nest(2, () {
           indent.writeln(
-            'BasicMessageChannel<Object$nullTag>(\'$channelName\', StandardMessageCodec());',
+            '\'$channelName\', StandardMessageCodec());',
           );
         });
         final String returnStatement = func.returnType == 'void'
             ? '// noop'
             : 'return ${func.returnType}.decode(replyMap[\'${Keys.result}\']$unwrapOperator);';
         indent.format('''
-final Map<Object$nullTag, Object$nullTag>$nullTag replyMap = await channel.send($sendArgument) as Map<Object$nullTag, Object$nullTag>$nullTag;
+final Map<Object$nullTag, Object$nullTag>$nullTag replyMap =\n\t\tawait channel.send($sendArgument) as Map<Object$nullTag, Object$nullTag>$nullTag;
 if (replyMap == null) {
 \tthrow PlatformException(
 \t\tcode: 'channel-error',
@@ -83,7 +84,7 @@ void _writeFlutterApi(
   DartOptions opt,
   Indent indent,
   Api api, {
-  String Function(Method) channelNameFunc,
+  String Function(Method)? channelNameFunc,
   bool isMockHandler = false,
 }) {
   assert(api.location == ApiLocation.flutter);
@@ -105,14 +106,14 @@ void _writeFlutterApi(
         indent.write('');
         indent.scoped('{', '}', () {
           indent.writeln(
-            'const BasicMessageChannel<Object$nullTag> channel =',
+            'const BasicMessageChannel<Object$nullTag> channel = BasicMessageChannel<Object$nullTag>(',
           );
           final String channelName = channelNameFunc == null
               ? makeChannelName(api, func)
               : channelNameFunc(func);
           indent.nest(2, () {
             indent.writeln(
-              'BasicMessageChannel<Object$nullTag>(\'$channelName\', StandardMessageCodec());',
+              '\'$channelName\', StandardMessageCodec());',
             );
           });
           final String messageHandlerSetter =
@@ -248,9 +249,10 @@ void generateDart(DartOptions opt, Root root, StringSink sink) {
             final Field field = klass.fields[index];
             indent.write('..${field.name} = ');
             if (customClassNames.contains(field.dataType)) {
-              indent.add(
-                'pigeonMap[\'${field.name}\'] != null ? ${field.dataType}.decode(pigeonMap[\'${field.name}\']$unwrapOperator) : null',
-              );
+              indent.format('''
+pigeonMap['${field.name}'] != null
+\t\t? ${field.dataType}.decode(pigeonMap['${field.name}']$unwrapOperator)
+\t\t: null''', leadingSpace: false, trailingNewline: false);
             } else {
               indent.add(
                 'pigeonMap[\'${field.name}\'] as ${_addGenericTypes(field.dataType, nullTag)}',
@@ -300,9 +302,10 @@ void generateTestDart(
   for (final Api api in root.apis) {
     if (api.location == ApiLocation.host && api.dartHostTestHandler != null) {
       final Api mockApi = Api(
-        name: api.dartHostTestHandler,
+        name: api.dartHostTestHandler!,
         methods: api.methods,
         location: ApiLocation.flutter,
+        dartHostTestHandler: api.dartHostTestHandler,
       );
       indent.writeln('');
       _writeFlutterApi(

packages/pigeon/lib/generator_tools.dart

@@ -8,7 +8,7 @@ import 'dart:mirrors';
 import 'ast.dart';
 
 /// The current version of pigeon. This must match the version in pubspec.yaml.
-const String pigeonVersion = '0.1.24';
+const String pigeonVersion = '0.2.0';
 
 /// Read all the content from [stdin] to a String.
 String readStdin() {
@@ -55,17 +55,26 @@ class Indent {
   }
 
   /// Replaces the newlines and tabs of input and adds it to the stream.
-  void format(String input) {
-    for (final String line in input.split('\n')) {
-      writeln(line.replaceAll('\t', tab));
+  void format(String input,
+      {bool leadingSpace = true, bool trailingNewline = true}) {
+    final List<String> lines = input.split('\n');
+    for (int i = 0; i < lines.length; ++i) {
+      final String line = lines[i];
+      if (i == 0 && !leadingSpace) {
+        addln(line.replaceAll('\t', tab));
+      } else if (i == lines.length - 1 && !trailingNewline) {
+        write(line.replaceAll('\t', tab));
+      } else {
+        writeln(line.replaceAll('\t', tab));
+      }
     }
   }
 
   /// Scoped increase of the ident level.  For the execution of [func] the
   /// indentation will be incremented.
   void scoped(
-    String begin,
-    String end,
+    String? begin,
+    String? end,
     Function func, {
     bool addTrailingNewline = true,
   }) {
@@ -83,12 +92,12 @@ class Indent {
 
   /// Like `scoped` but writes the current indentation level.
   void writeScoped(
-    String begin,
+    String? begin,
     String end,
     Function func, {
     bool addTrailingNewline = true,
   }) {
-    scoped(str() + begin ?? '', end, func,
+    scoped(str() + (begin ?? ''), end, func,
         addTrailingNewline: addTrailingNewline);
   }
 
@@ -133,7 +142,10 @@ String makeChannelName(Api api, Method func) {
 /// Represents the mapping of a Dart datatype to a Host datatype.
 class HostDatatype {
   /// Parametric constructor for HostDatatype.
-  HostDatatype({this.datatype, this.isBuiltin});
+  HostDatatype({
+    required this.datatype,
+    required this.isBuiltin,
+  });
 
   /// The [String] that can be printed into host code to represent the type.
   final String datatype;
@@ -147,9 +159,9 @@ class HostDatatype {
 /// `builtinResolver` will return the host datatype for the Dart datatype for
 /// builtin types.  `customResolver` can modify the datatype of custom types.
 HostDatatype getHostDatatype(
-    Field field, List<Class> classes, String Function(String) builtinResolver,
-    {String Function(String) customResolver}) {
-  final String datatype = builtinResolver(field.dataType);
+    Field field, List<Class> classes, String? Function(String) builtinResolver,
+    {String Function(String)? customResolver}) {
+  final String? datatype = builtinResolver(field.dataType);
   if (datatype == null) {
     if (classes.map((Class x) => x.name).contains(field.dataType)) {
       final String customName = customResolver != null

packages/pigeon/lib/java_generator.dart

@@ -20,11 +20,17 @@ const Map<String, String> _javaTypeForDartTypeMap = <String, String>{
 
 /// Options that control how Java code will be generated.
 class JavaOptions {
+  /// Creates a [JavaOptions] object
+  JavaOptions({
+    this.className,
+    this.package,
+  });
+
   /// The name of the class that will house all the generated classes.
-  String className;
+  String? className;
 
   /// The package where the generated class will live.
-  String package;
+  String? package;
 }
 
 void _writeHostApi(Indent indent, Api api) {
@@ -198,7 +204,7 @@ String _makeSetter(Field field) {
   return 'set$uppercased';
 }
 
-String _javaTypeForDartType(String datatype) {
+String? _javaTypeForDartType(String datatype) {
   return _javaTypeForDartTypeMap[datatype];
 }
 
@@ -236,11 +242,10 @@ void generateJava(JavaOptions options, Root root, StringSink sink) {
   indent.writeln('import java.util.HashMap;');
 
   indent.addln('');
-  assert(options.className != null);
   indent.writeln('/** Generated class from Pigeon. */');
   indent.writeln(
       '@SuppressWarnings({"unused", "unchecked", "CodeBlock2Expr", "RedundantSuppression"})');
-  indent.write('public class ${options.className} ');
+  indent.write('public class ${options.className!} ');
   indent.scoped('{', '}', () {
     for (final Class klass in root.classes) {
       indent.addln('');

packages/pigeon/lib/objc_generator.dart

@@ -8,17 +8,20 @@ import 'generator_tools.dart';
 /// Options that control how Objective-C code will be generated.
 class ObjcOptions {
   /// Parametric constructor for ObjcOptions.
-  ObjcOptions({this.header, this.prefix});
+  ObjcOptions({
+    this.header,
+    this.prefix,
+  });
 
   /// The path to the header that will get placed in the source filed (example:
   /// "foo.h").
-  String header;
+  String? header;
 
   /// Prefix that will be appended before all generated classes and protocols.
-  String prefix;
+  String? prefix;
 }
 
-String _className(String prefix, String className) {
+String _className(String? prefix, String className) {
   if (prefix != null) {
     return '$prefix$className';
   } else {
@@ -58,12 +61,12 @@ const Map<String, String> _propertyTypeForDartTypeMap = <String, String>{
   'Map': 'strong',
 };
 
-String _objcTypeForDartType(String type) {
+String? _objcTypeForDartType(String type) {
   return _objcTypeForDartTypeMap[type];
 }
 
 String _propertyTypeForDartType(String type) {
-  final String result = _propertyTypeForDartTypeMap[type];
+  final String? result = _propertyTypeForDartTypeMap[type];
   if (result == null) {
     return 'assign';
   } else {
@@ -72,7 +75,7 @@ String _propertyTypeForDartType(String type) {
 }
 
 void _writeClassDeclarations(
-    Indent indent, List<Class> classes, String prefix) {
+    Indent indent, List<Class> classes, String? prefix) {
   for (final Class klass in classes) {
     indent.writeln('@interface ${_className(prefix, klass.name)} : NSObject');
     for (final Field field in klass.fields) {
@@ -191,7 +194,7 @@ void generateObjcHeader(ObjcOptions options, Root root, StringSink sink) {
 }
 
 String _dictGetter(
-    List<String> classnames, String dict, Field field, String prefix) {
+    List<String> classnames, String dict, Field field, String? prefix) {
   if (classnames.contains(field.dataType)) {
     String className = field.dataType;
     if (prefix != null) {

packages/pigeon/lib/pigeon_cl.dart

@@ -11,7 +11,7 @@ import 'package:pigeon/pigeon_lib.dart';
 
 /// This creates a relative path from `from` to `input`, the output being a
 /// posix path on all platforms.
-String _posixRelative(String input, {String from}) {
+String _posixRelative(String input, {required String from}) {
   final path.Context context = path.Context(style: path.Style.posix);
   final String rawInputPath = input;
   final String absInputPath = File(rawInputPath).absolute.path;
@@ -27,19 +27,19 @@ String _posixRelative(String input, {String from}) {
 /// This is the main entrypoint for the command-line tool.  [args] are the
 /// commmand line arguments and there is an optional [packageConfig] to
 /// accomodate users that want to integrate pigeon with other build systems.
-Future<void> runCommandLine(List<String> args, {Uri packageConfig}) async {
+Future<void> runCommandLine(List<String> args, {Uri? packageConfig}) async {
   final PigeonOptions opts = Pigeon.parseArgs(args);
   final Directory tempDir = Directory.systemTemp.createTempSync(
     'flutter_pigeon.',
   );
 
   String importLine = '';
   if (opts.input != null) {
-    final String relInputPath = _posixRelative(opts.input, from: tempDir.path);
+    final String relInputPath = _posixRelative(opts.input!, from: tempDir.path);
     importLine = 'import \'$relInputPath\';\n';
   }
   final String code = """
-// @dart = 2.2
+// @dart = 2.12
 $importLine
 import 'dart:io';
 import 'dart:isolate';