issue(160501): added generation of empty classes in dart

packages/pigeon/example/app/android/app/src/main/kotlin/dev/flutter/pigeon_example_app/EventChannelMessages.g.kt

@@ -1,68 +1,98 @@
 // 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.
-// Autogenerated from Pigeon, do not edit directly.
+// Autogenerated from Pigeon (v22.7.0), do not edit directly.
 // See also: https://pub.dev/packages/pigeon
 @file:Suppress("UNCHECKED_CAST", "ArrayInDataClass")
 
+
+import android.util.Log
+import io.flutter.plugin.common.BasicMessageChannel
 import io.flutter.plugin.common.BinaryMessenger
 import io.flutter.plugin.common.EventChannel
-import io.flutter.plugin.common.StandardMessageCodec
+import io.flutter.plugin.common.MessageCodec
 import io.flutter.plugin.common.StandardMethodCodec
+import io.flutter.plugin.common.StandardMessageCodec
 import java.io.ByteArrayOutputStream
 import java.nio.ByteBuffer
 
 /**
- * Generated class from Pigeon that represents data sent in messages. This class should not be
- * extended by any user class outside of the generated file.
+ * Generated class from Pigeon that represents data sent in messages.
+ * This class should not be extended by any user class outside of the generated file.
  */
-sealed class PlatformEvent
+sealed class PlatformEvent 
 /** Generated class from Pigeon that represents data sent in messages. */
-data class IntEvent(val data: Long) : PlatformEvent() {
+data class IntEvent (
+  val data: Long
+) : PlatformEvent()
+ {
   companion object {
     fun fromList(pigeonVar_list: List<Any?>): IntEvent {
       val data = pigeonVar_list[0] as Long
       return IntEvent(data)
     }
   }
-
   fun toList(): List<Any?> {
     return listOf(
-        data,
+      data,
     )
   }
 }
 
 /** Generated class from Pigeon that represents data sent in messages. */
-data class StringEvent(val data: String) : PlatformEvent() {
+data class StringEvent (
+  val data: String
+) : PlatformEvent()
+ {
   companion object {
     fun fromList(pigeonVar_list: List<Any?>): StringEvent {
       val data = pigeonVar_list[0] as String
       return StringEvent(data)
     }
   }
-
   fun toList(): List<Any?> {
     return listOf(
-        data,
+      data,
     )
   }
 }
 
+/** Generated class from Pigeon that represents data sent in messages. */
+ class EmptyEvent (
+) : PlatformEvent()
+ {
+  companion object {
+    fun fromList(pigeonVar_list: List<Any?>): EmptyEvent {
+      return EmptyEvent()
+    }
+  }
+  fun toList(): List<Any?> {
+    return listOf(
+    )
+  }
+}
 private open class EventChannelMessagesPigeonCodec : StandardMessageCodec() {
   override fun readValueOfType(type: Byte, buffer: ByteBuffer): Any? {
     return when (type) {
       129.toByte() -> {
-        return (readValue(buffer) as? List<Any?>)?.let { IntEvent.fromList(it) }
+        return (readValue(buffer) as? List<Any?>)?.let {
+          IntEvent.fromList(it)
+        }
       }
       130.toByte() -> {
-        return (readValue(buffer) as? List<Any?>)?.let { StringEvent.fromList(it) }
+        return (readValue(buffer) as? List<Any?>)?.let {
+          StringEvent.fromList(it)
+        }
+      }
+      131.toByte() -> {
+        return (readValue(buffer) as? List<Any?>)?.let {
+          EmptyEvent.fromList(it)
+        }
       }
       else -> super.readValueOfType(type, buffer)
     }
   }
-
-  override fun writeValue(stream: ByteArrayOutputStream, value: Any?) {
+  override fun writeValue(stream: ByteArrayOutputStream, value: Any?)   {
     when (value) {
       is IntEvent -> {
         stream.write(129)
@@ -72,15 +102,21 @@ private open class EventChannelMessagesPigeonCodec : StandardMessageCodec() {
         stream.write(130)
         writeValue(stream, value.toList())
       }
+      is EmptyEvent -> {
+        stream.write(131)
+        writeValue(stream, value.toList())
+      }
       else -> super.writeValue(stream, value)
     }
   }
 }
 
-val EventChannelMessagesPigeonMethodCodec = StandardMethodCodec(EventChannelMessagesPigeonCodec())
+val EventChannelMessagesPigeonMethodCodec = StandardMethodCodec(EventChannelMessagesPigeonCodec());
+
 
-private class PigeonStreamHandler<T>(val wrapper: PigeonEventChannelWrapper<T>) :
-    EventChannel.StreamHandler {
+private class PigeonStreamHandler<T>(
+    val wrapper: PigeonEventChannelWrapper<T>
+) : EventChannel.StreamHandler {
   var pigeonSink: PigeonEventSink<T>? = null
 
   override fun onListen(p0: Any?, sink: EventChannel.EventSink) {
@@ -108,27 +144,22 @@ class PigeonEventSink<T>(private val sink: EventChannel.EventSink) {
   fun error(errorCode: String, errorMessage: String?, errorDetails: Any?) {
     sink.error(errorCode, errorMessage, errorDetails)
   }
-
-  fun endOfStream() {
+  
+  fun endOfStream() { 
     sink.endOfStream()
   }
 }
-
+      
 abstract class StreamEventsStreamHandler : PigeonEventChannelWrapper<PlatformEvent> {
   companion object {
-    fun register(
-        messenger: BinaryMessenger,
-        streamHandler: StreamEventsStreamHandler,
-        instanceName: String = ""
-    ) {
-      var channelName: String =
-          "dev.flutter.pigeon.pigeon_example_package.EventChannelMethods.streamEvents"
+    fun register(messenger: BinaryMessenger, streamHandler: StreamEventsStreamHandler, instanceName: String = "") {
+      var channelName: String = "dev.flutter.pigeon.pigeon_example_package.EventChannelMethods.streamEvents"
       if (instanceName.isNotEmpty()) {
         channelName += ".$instanceName"
       }
       val internalStreamHandler = PigeonStreamHandler<PlatformEvent>(streamHandler)
-      EventChannel(messenger, channelName, EventChannelMessagesPigeonMethodCodec)
-          .setStreamHandler(internalStreamHandler)
+      EventChannel(messenger, channelName, EventChannelMessagesPigeonMethodCodec).setStreamHandler(internalStreamHandler)
     }
   }
 }
+

packages/pigeon/example/app/android/app/src/main/kotlin/dev/flutter/pigeon_example_app/MainActivity.kt

@@ -13,6 +13,7 @@ import PigeonEventSink
 import PlatformEvent
 import StreamEventsStreamHandler
 import StringEvent
+import EmptyEvent
 import android.os.Handler
 import android.os.Looper
 import io.flutter.embedding.android.FlutterActivity
@@ -72,6 +73,10 @@ class EventListener : StreamEventsStreamHandler() {
     eventSink?.success(StringEvent(data = event))
   }
 
+  fun onEmptyEvent() {
+    eventSink?.success(EmptyEvent())
+  }
+
   fun onEventsDone() {
     eventSink?.endOfStream()
     eventSink = null
@@ -93,6 +98,11 @@ fun sendEvents(eventListener: EventListener) {
                 eventListener.onIntEvent(count.toLong())
                 count++
               }
+            } else if (count % 5 == 0) {
+              handler.post {
+                eventListener.onEmptyEvent()
+                count++
+              }
             } else {
               handler.post {
                 eventListener.onStringEvent(count.toString())

packages/pigeon/example/app/ios/Runner/AppDelegate.swift

@@ -66,6 +66,12 @@ class EventListener: StreamEventsStreamHandler {
     }
   }
 
+  func onEmptyEvent() {
+    if let eventSink = eventSink {
+      eventSink.success(EmptyEvent())
+    }
+  }
+
   func onEventsDone() {
     eventSink?.endOfStream()
     eventSink = nil
@@ -84,6 +90,8 @@ func sendEvents(_ eventListener: EventListener) {
       } else {
         if (count % 2) == 0 {
           eventListener.onIntEvent(event: Int64(count))
+        } else if (count % 5) == 0 {
+          eventListener.onEmptyEvent()
         } else {
           eventListener.onStringEvent(event: String(count))
         }

packages/pigeon/example/app/ios/Runner/EventChannelMessages.g.swift

@@ -1,7 +1,7 @@
 // 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.
-// Autogenerated from Pigeon, do not edit directly.
+// Autogenerated from Pigeon (v22.7.0), do not edit directly.
 // See also: https://pub.dev/packages/pigeon
 
 import Foundation
@@ -33,6 +33,7 @@ protocol PlatformEvent {
 struct IntEvent: PlatformEvent {
   var data: Int64
 
+
   // swift-format-ignore: AlwaysUseLowerCamelCase
   static func fromList(_ pigeonVar_list: [Any?]) -> IntEvent? {
     let data = pigeonVar_list[0] as! Int64
@@ -52,6 +53,7 @@ struct IntEvent: PlatformEvent {
 struct StringEvent: PlatformEvent {
   var data: String
 
+
   // swift-format-ignore: AlwaysUseLowerCamelCase
   static func fromList(_ pigeonVar_list: [Any?]) -> StringEvent? {
     let data = pigeonVar_list[0] as! String
@@ -67,13 +69,31 @@ struct StringEvent: PlatformEvent {
   }
 }
 
+/// Generated class from Pigeon that represents data sent in messages.
+struct EmptyEvent: PlatformEvent {
+
+
+  // swift-format-ignore: AlwaysUseLowerCamelCase
+  static func fromList(_ pigeonVar_list: [Any?]) -> EmptyEvent? {
+
+    return EmptyEvent(
+    )
+  }
+  func toList() -> [Any?] {
+    return [
+    ]
+  }
+}
+
 private class EventChannelMessagesPigeonCodecReader: FlutterStandardReader {
   override func readValue(ofType type: UInt8) -> Any? {
     switch type {
     case 129:
       return IntEvent.fromList(self.readValue() as! [Any?])
     case 130:
       return StringEvent.fromList(self.readValue() as! [Any?])
+    case 131:
+      return EmptyEvent.fromList(self.readValue() as! [Any?])
     default:
       return super.readValue(ofType: type)
     }
@@ -88,6 +108,9 @@ private class EventChannelMessagesPigeonCodecWriter: FlutterStandardWriter {
     } else if let value = value as? StringEvent {
       super.writeByte(130)
       super.writeValue(value.toList())
+    } else if let value = value as? EmptyEvent {
+      super.writeByte(131)
+      super.writeValue(value.toList())
     } else {
       super.writeValue(value)
     }
@@ -105,12 +128,11 @@ private class EventChannelMessagesPigeonCodecReaderWriter: FlutterStandardReader
 }
 
 class EventChannelMessagesPigeonCodec: FlutterStandardMessageCodec, @unchecked Sendable {
-  static let shared = EventChannelMessagesPigeonCodec(
-    readerWriter: EventChannelMessagesPigeonCodecReaderWriter())
+  static let shared = EventChannelMessagesPigeonCodec(readerWriter: EventChannelMessagesPigeonCodecReaderWriter())
 }
 
-var eventChannelMessagesPigeonMethodCodec = FlutterStandardMethodCodec(
-  readerWriter: EventChannelMessagesPigeonCodecReaderWriter())
+var eventChannelMessagesPigeonMethodCodec = FlutterStandardMethodCodec(readerWriter: EventChannelMessagesPigeonCodecReaderWriter());
+
 
 private class PigeonStreamHandler<ReturnType>: NSObject, FlutterStreamHandler {
   private let wrapper: PigeonEventChannelWrapper<ReturnType>
@@ -162,18 +184,16 @@ class PigeonEventSink<ReturnType> {
 }
 
 class StreamEventsStreamHandler: PigeonEventChannelWrapper<PlatformEvent> {
-  static func register(
-    with messenger: FlutterBinaryMessenger,
-    instanceName: String = "",
-    streamHandler: StreamEventsStreamHandler
-  ) {
+  static func register(with messenger: FlutterBinaryMessenger, 
+                      instanceName: String = "",
+                      streamHandler: StreamEventsStreamHandler) {
     var channelName = "dev.flutter.pigeon.pigeon_example_package.EventChannelMethods.streamEvents"
     if !instanceName.isEmpty {
       channelName += ".\(instanceName)"
     }
     let internalStreamHandler = PigeonStreamHandler<PlatformEvent>(wrapper: streamHandler)
-    let channel = FlutterEventChannel(
-      name: channelName, binaryMessenger: messenger, codec: eventChannelMessagesPigeonMethodCodec)
+    let channel = FlutterEventChannel(name: channelName, binaryMessenger: messenger, codec: eventChannelMessagesPigeonMethodCodec)
     channel.setStreamHandler(internalStreamHandler)
   }
 }
+

packages/pigeon/example/app/lib/main.dart

@@ -99,6 +99,8 @@ class _MyHomePageState extends State<MyHomePage> {
         case StringEvent():
           final String stringData = event.data;
           yield '$stringData, ';
+        case EmptyEvent():
+          yield 'EmptyEvent, ';
       }
     }
   }