clean up API for file_generator.dart

test/file_generator_test.dart

 #!/usr/bin/env dart
 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library file_generator_test;
 
 import 'package:protoc_plugin/indenting_writer.dart';
 import 'package:protoc_plugin/src/descriptor.pb.dart';
 import 'package:protoc_plugin/src/plugin.pb.dart';
@@ skipping 109 matching lines @@
 }
 
 class _ReadonlyPhoneNumber extends PhoneNumber with ReadonlyMessageMixin {}
 
 ''';
     FileDescriptorProto fd = buildFileDescriptor();
     var options = parseGenerationOptions(
         new CodeGeneratorRequest(), new CodeGeneratorResponse());
     FileGenerator fg = new FileGenerator(fd);
     link(options, [fg]);
-
-    IndentingWriter writer = new IndentingWriter();
-    fg.generate(writer);
-    expect(writer.toString(), expected);
+    expect(fg.generateMainFile(), expected);
   });
 
   test('FileGenerator outputs a pbjson.dart file for a proto with one message',
       () {
     var expected = r'''
 ///
 //  Generated code. Do not modify.
 ///
 library test_pbjson;
 
 const PhoneNumber$json = const {
   '1': 'PhoneNumber',
   '2': const [
     const {'1': 'number', '3': 1, '4': 2, '5': 9},
     const {'1': 'type', '3': 2, '4': 1, '5': 5, '6': ''},
     const {'1': 'name', '3': 3, '4': 1, '5': 9, '7': r'$'},
   ],
 };
 
 ''';
     FileDescriptorProto fd = buildFileDescriptor();
     var options = parseGenerationOptions(
         new CodeGeneratorRequest(), new CodeGeneratorResponse());
     FileGenerator fg = new FileGenerator(fd);
     link(options, [fg]);
-
-    IndentingWriter writer = new IndentingWriter();
-    fg.generateJsonDart(writer);
-    expect(writer.toString(), expected);
+    expect(fg.generateJsonFile(), expected);
   });
 
   test('FileGenerator generates files for a top-level enum', () {
     // NOTE: Below > 80 cols because it is matching generated code > 80 cols.
 
     String expected = r'''
 ///
 //  Generated code. Do not modify.
 ///
 library test;
@@ skipping 34 matching lines @@
 
 ''';
 
     FileDescriptorProto fd =
         buildFileDescriptor(phoneNumber: false, topLevelEnum: true);
     var options = parseGenerationOptions(
         new CodeGeneratorRequest(), new CodeGeneratorResponse());
 
     FileGenerator fg = new FileGenerator(fd);
     link(options, [fg]);
-
-    var writer = new IndentingWriter();
-    fg.generate(writer);
-    expect(writer.toString(), expected);
-
-    writer = new IndentingWriter();
-    fg.generateEnumFile(writer);
-    expect(writer.toString(), expectedEnum);
+    expect(fg.generateMainFile(), expected);
+    expect(fg.generateEnumFile(), expectedEnum);
   });
 
   test('FileGenerator generates a .pbjson.dart file for a top-level enum', () {
     String expected = r'''
 ///
 //  Generated code. Do not modify.
 ///
 library test_pbjson;
 
 const PhoneType$json = const {
   '1': 'PhoneType',
   '2': const [
     const {'1': 'MOBILE', '2': 0},
     const {'1': 'HOME', '2': 1},
     const {'1': 'WORK', '2': 2},
     const {'1': 'BUSINESS', '2': 2},
   ],
 };
 
 ''';
 
     FileDescriptorProto fd =
         buildFileDescriptor(phoneNumber: false, topLevelEnum: true);
     var options = parseGenerationOptions(
         new CodeGeneratorRequest(), new CodeGeneratorResponse());
 
     FileGenerator fg = new FileGenerator(fd);
     link(options, [fg]);
-
-    var writer = new IndentingWriter();
-    fg.generateJsonDart(writer);
-    expect(writer.toString(), expected);
+    expect(fg.generateJsonFile(), expected);
   });
 
   test('FileGenerator outputs library for a .proto in a package', () {
     String expected = r'''
 ///
 //  Generated code. Do not modify.
 ///
 library pb_library_test;
 
 import 'package:protobuf/protobuf.dart';
 
 ''';
     FileDescriptorProto fd = buildFileDescriptor();
     fd.package = "pb_library";
     var options = parseGenerationOptions(
         new CodeGeneratorRequest(), new CodeGeneratorResponse());
 
     FileGenerator fg = new FileGenerator(fd);
     link(options, [fg]);
 
     var writer = new IndentingWriter();
-    fg.generateHeader(writer);
+    fg.writeMainHeader(writer);
     expect(writer.toString(), expected);
   });
 
   test('FileGenerator outputs a fixnum import when needed', () {
     String expected = r'''
 ///
 //  Generated code. Do not modify.
 ///
 library test;
 
@@ skipping 12 matching lines @@
             ..type = FieldDescriptorProto_Type.TYPE_INT64
         ]));
 
     var options = parseGenerationOptions(
         new CodeGeneratorRequest(), new CodeGeneratorResponse());
 
     FileGenerator fg = new FileGenerator(fd);
     link(options, [fg]);
 
     var writer = new IndentingWriter();
-    fg.generateHeader(writer);
+    fg.writeMainHeader(writer);
     expect(writer.toString(), expected);
   });
 
   test('FileGenerator outputs extra imports for a service', () {
     String expected = r'''
 ///
 //  Generated code. Do not modify.
 ///
 library test;
 
 import 'dart:async';
 
 import 'package:protobuf/protobuf.dart';
 
 import 'test.pbjson.dart';
 
 ''';
     FileDescriptorProto fd = new FileDescriptorProto()
       ..name = 'test'
       ..service.add(new ServiceDescriptorProto());
 
     var options = parseGenerationOptions(
         new CodeGeneratorRequest(), new CodeGeneratorResponse());
 
     FileGenerator fg = new FileGenerator(fd);
     link(options, [fg]);
 
     var writer = new IndentingWriter();
-    fg.generateHeader(writer);
+    fg.writeMainHeader(writer);
     expect(writer.toString(), expected);
   });
 
   test('FileGenerator handles field_name options', () {
     // NOTE: Below > 80 cols because it is matching generated code > 80 cols.
     String expected = r'''
 ///
 //  Generated code. Do not modify.
 ///
 library test;
@@ skipping 44 matching lines @@
 ''';
     FileDescriptorProto fd = buildFileDescriptor();
     var request = new CodeGeneratorRequest();
     request.parameter = 'field_name=PhoneNumber.number|No,'
         'field_name=PhoneNumber.name|Name_,'
         'field_name=PhoneNumber.type|The_type';
     var options = parseGenerationOptions(request, new CodeGeneratorResponse());
 
     FileGenerator fg = new FileGenerator(fd);
     link(options, [fg]);
-
-    var writer = new IndentingWriter();
-    fg.generate(writer);
-    expect(writer.toString(), expected);
+    expect(fg.generateMainFile(), expected);
   });
 
   test('FileGenerator generates imports for .pb.dart files', () {
     // NOTE: Below > 80 cols because it is matching generated code > 80 cols.
     String expected = r'''
 ///
 //  Generated code. Do not modify.
 ///
 library test;
 
@@ skipping 154 matching lines @@
     FileDescriptorProto fd = new FileDescriptorProto()
       ..name = 'test.proto'
       ..messageType.add(md);
     fd.dependency.addAll(['package1.proto', 'package2.proto']);
     var request = new CodeGeneratorRequest();
     var response = new CodeGeneratorResponse();
     var options = parseGenerationOptions(request, response);
 
     FileGenerator fg = new FileGenerator(fd);
     link(options, [fg, new FileGenerator(fd1), new FileGenerator(fd2)]);
-
-    var writer = new IndentingWriter();
-    fg.generate(writer);
-    expect(writer.toString(), expected);
-
-    writer = new IndentingWriter();
-    fg.generateJsonDart(writer);
-    expect(writer.toString(), expectedJson);
+    expect(fg.generateMainFile(), expected);
+    expect(fg.generateJsonFile(), expectedJson);
   });
 }