diff --git a/packages/pigeon/bin/pigeon.dart b/packages/pigeon/bin/pigeon.dart
index 1a424e092f0..650716a0ad3 100644
--- a/packages/pigeon/bin/pigeon.dart
+++ b/packages/pigeon/bin/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.
 
-// @dart = 2.2
+// @dart = 2.3
 
 import 'dart:async';
 import 'dart:io';
@@ -26,18 +26,122 @@ String _posixRelative(String input, {String from}) {
   return context.relative(posixAbsInputPath, from: posixTempPath);
 }
 
+/// aa_bb_cc -> AaBbCc
+String _underLineToHump(String str) {
+  return str
+      .split('_')
+      .map((String e) => e.replaceRange(0, 1, e[0].toUpperCase()))
+      .join();
+}
+
+/// AaBbCc -> aa_bb_cc
+String _humpToUnderLine(String str) {
+  return str.replaceAllMapped(RegExp(r'(^[A-Z])|([A-Z])'), (Match match) {
+    if (match[2] != null) {
+      return '_${match[2]?.toLowerCase()}';
+    } else {
+      return match[1]?.toLowerCase() ?? '';
+    }
+  });
+}
+
 Future<void> main(List<String> args) async {
   final PigeonOptions opts = Pigeon.parseArgs(args);
   final Directory tempDir = Directory.systemTemp.createTempSync(
     'flutter_pigeon.',
   );
+  if (opts.isDir) {
+    final Directory inputDir = Directory(opts.inputDir);
+    if (!inputDir.existsSync()) {
+      tempDir.deleteSync(recursive: true);
+      exit(exitCode);
+    }
+
+    final List<FileSystemEntity> list = inputDir.listSync(recursive: true);
+    final List<String> inputDirs = path.split(opts.inputDir);
+    for (int i = 0; i < list.length; i++) {
+      final FileSystemEntity element = list[i];
+      if (element is File) {
+        final String input = element.path;
+        final List<String> fileParents = path.split(input);
+        final String fileName = path.basenameWithoutExtension(input);
+        final String outName = _humpToUnderLine('${fileName}_${opts.suffit}');
+        final String humpName = _underLineToHump(outName);
+        opts.input = input;
+
+        final List<String> middle =
+            fileParents.sublist(inputDirs.length, fileParents.length - 1);
+        final List<String> javaPackage = middle.isNotEmpty
+            ? <String>[
+                '--java_package',
+                '${opts.javaOptions.package}.${middle.join('.')}',
+              ]
+            : <String>[
+                '--java_package',
+                opts.javaOptions.package,
+              ];
+
+        final List<String> objcPrefix = opts.objcOptions.prefix != null
+            ? <String>[
+                '--objc_prefix',
+                opts.objcOptions.prefix,
+              ]
+            : List<String>.empty();
 
+        final List<String> fileArgs = <String>[
+          '--input',
+          input,
+          '--dart_out',
+          path.join(
+            opts.dartOutDir.replaceAll('/', path.separator),
+            middle.join(path.separator),
+            '$outName.dart',
+          ),
+          '--java_out',
+          path.join(
+            opts.javaOutDir.replaceAll('/', path.separator),
+            opts.javaOptions.package?.replaceAll('.', path.separator) ?? '',
+            middle.join(path.separator),
+            '$humpName.java',
+          ),
+          ...javaPackage,
+          '--objc_header_out',
+          path.join(
+            opts.objcOutDir.replaceAll('/', path.separator),
+            middle.join(path.separator),
+            '$humpName.h',
+          ),
+          '--objc_source_out',
+          path.join(
+            opts.objcOutDir.replaceAll('/', path.separator),
+            middle.join(path.separator),
+            '$humpName.m',
+          ),
+          ...objcPrefix,
+        ];
+
+        print('generate file $input');
+        print('generate args $fileArgs');
+        final int code = await _genFile(fileArgs, opts, tempDir);
+        print('generate resule $code $input');
+        print('============================');
+      }
+    }
+  } else {
+    await _genFile(args, opts, tempDir);
+  }
+  tempDir.deleteSync(recursive: true);
+  exit(exitCode);
+}
+
+Future<int> _genFile(
+    List<String> args, PigeonOptions opts, Directory tempDir) async {
   String importLine = '';
   if (opts.input != null) {
     final String relInputPath = _posixRelative(opts.input, from: tempDir.path);
     importLine = 'import \'$relInputPath\';\n';
   }
-  final String code = """// @dart = 2.2
+  final String code = """// @dart = 2.3
 $importLine
 import 'dart:io';
 import 'dart:isolate';
@@ -68,6 +172,5 @@ void main(List<String> args, SendPort sendPort) async {
     }
   });
   final int exitCode = await completer.future;
-  tempDir.deleteSync(recursive: true);
-  exit(exitCode);
+  return exitCode;
 }
diff --git a/packages/pigeon/example/README.md b/packages/pigeon/example/README.md
index 8b8409d84cf..91d1efb5cdb 100644
--- a/packages/pigeon/example/README.md
+++ b/packages/pigeon/example/README.md
@@ -41,6 +41,26 @@ flutter pub run pigeon \
   --java_out ./android/app/src/main/java/dev/flutter/pigeon/Pigeon.java \
   --java_package "dev.flutter.pigeon"
 ```
+### Directory model generated
+
+Enable Directory model generated
+
+```sh
+flutter pub run pigeon --dir
+```
+
+Other args
+
+```sh
+flutter pub run pigeon --dir \
+  --input_dir pigeons \
+  --dart_out_dir lib \
+  --objc_out_dir ios/Runner \
+  --objc_prefix FL \
+  --java_out_dir android/app/src/main/java \
+  --java_package "dev.flutter.pigeon"
+```
+
 
 ### AppDelegate.m
 
diff --git a/packages/pigeon/lib/dart_generator.dart b/packages/pigeon/lib/dart_generator.dart
index 80f7cb5e616..bf8926433e7 100644
--- a/packages/pigeon/lib/dart_generator.dart
+++ b/packages/pigeon/lib/dart_generator.dart
@@ -134,14 +134,14 @@ void _writeFlutterApi(
                   : func.returnType == 'void'
                       ? 'return;'
                       : 'return null;';
-              indent.write('if (message == null) ');
-              indent.scoped('{', '}', () {
-                indent.writeln(emptyReturnStatement);
-              });
               String call;
               if (argType == 'void') {
                 call = 'api.${func.name}()';
               } else {
+                indent.write('if (message == null) ');
+                indent.scoped('{', '}', () {
+                  indent.writeln(emptyReturnStatement);
+                });
                 indent.writeln(
                   'final $argType input = $argType.decode(message);',
                 );
diff --git a/packages/pigeon/lib/pigeon_lib.dart b/packages/pigeon/lib/pigeon_lib.dart
index 22d3871d6b2..5bb69122595 100644
--- a/packages/pigeon/lib/pigeon_lib.dart
+++ b/packages/pigeon/lib/pigeon_lib.dart
@@ -117,6 +117,24 @@ bool _isFlutterApi(ClassMirror apiMirror) {
 
 /// Options used when running the code generator.
 class PigeonOptions {
+  /// Enable directory model
+  bool isDir;
+
+  /// Directory model suffit that will be appended after all generated classes or file.
+  String suffit;
+
+  /// Path to the directory which will be processed.
+  String inputDir;
+
+  /// Path to the dart direcotry that will be generated.
+  String dartOutDir;
+
+  /// Path to the Objective-C source and header direcotry will be generated.
+  String objcOutDir;
+
+  /// Path to the java direcotry that will be generated.
+  String javaOutDir;
+
   /// Path to the file which will be processed.
   String input;
 
@@ -284,6 +302,19 @@ options:
   }
 
   static final ArgParser _argParser = ArgParser()
+    ..addFlag('dir', abbr: 'd', help: 'Enable directory model')
+    ..addOption('suffit',
+        defaultsTo: 'pigeon',
+        help: 'Directory model suffix for generated classes or files.')
+    ..addOption('input_dir', defaultsTo: 'pigeons', help: 'Path to pigeon.')
+    ..addOption('dart_out_dir',
+        defaultsTo: 'lib', help: 'Path to generated Dart source directory.')
+    ..addOption('java_out_dir',
+        defaultsTo: 'android/src/main/java',
+        help: 'Path to generated Java directory.')
+    ..addOption('objc_out_dir',
+        defaultsTo: 'ios/Classes',
+        help: 'Path to generated Objective-C source and header directory.')
     ..addOption('input', help: 'REQUIRED: Path to pigeon file.')
     ..addOption('dart_out',
         help: 'REQUIRED: Path to generated Dart source file (.dart).')
@@ -307,6 +338,12 @@ options:
     final ArgResults results = _argParser.parse(args);
 
     final PigeonOptions opts = PigeonOptions();
+    opts.isDir = results['dir'];
+    opts.suffit = results['suffit'];
+    opts.inputDir = results['input_dir'];
+    opts.dartOutDir = results['dart_out_dir'];
+    opts.objcOutDir = results['objc_out_dir'];
+    opts.javaOutDir = results['java_out_dir'];
     opts.input = results['input'];
     opts.dartOut = results['dart_out'];
     opts.dartTestOut = results['dart_test_out'];
@@ -327,6 +364,7 @@ options:
       sink = stdout;
     } else {
       file = File(output);
+      file.parent.createSync(recursive: true);
       sink = file.openWrite();
     }
     func(sink);
diff --git a/packages/pigeon/pubspec.yaml b/packages/pigeon/pubspec.yaml
index b3ea3c2fefc..71f82909500 100644
--- a/packages/pigeon/pubspec.yaml
+++ b/packages/pigeon/pubspec.yaml
@@ -8,4 +8,4 @@ dependencies:
 dev_dependencies:
   test: ^1.11.1
 environment:
-  sdk: '>=2.2.0 <3.0.0'
+  sdk: '>=2.3.0 <3.0.0'