[pigeon] Moves all codec logic to singular custom codec (flutter#6600)

[pigeon] Moves all codec logic to singular custom codec.

Also fixes a few small codec related bugs that have cropped up over time.

fixes flutter#147454
fixes flutter#147127
fixes flutter#147587
fixes flutter#148065

Author: tarrinneal

packages/pigeon/CHANGELOG.md

@@ -1,3 +1,12 @@
+## 20.0.0
+
+* Moves all codec logic to single custom codec per file.
+* **Breaking Change** Limits the number of total custom types to 126.
+  * If more than 126 custom types are needed, consider breaking up your definition files.
+* Fixes bug that prevented collection subtypes from being added properly.
+* [swift] Adds `@unchecked Sendable` to codec method.
+* [objc] [cpp] Fixes bug that prevented setting custom header import path.
+
 ## 19.0.2
 
 * [kotlin] Adds the `@JvmOverloads` to the `HostApi` setUp method. This prevents the calling Java code from having to provide an empty `String` as Kotlin provides it by default  

packages/pigeon/example/app/android/app/src/main/java/io/flutter/plugins/Messages.java

@@ -181,7 +181,7 @@ ArrayList<Object> toList() {
       ArrayList<Object> toListResult = new ArrayList<Object>(4);
       toListResult.add(name);
       toListResult.add(description);
-      toListResult.add(code == null ? null : code.index);
+      toListResult.add(code);
       toListResult.add(data);
       return toListResult;
     }
@@ -193,13 +193,45 @@ ArrayList<Object> toList() {
       Object description = __pigeon_list.get(1);
       pigeonResult.setDescription((String) description);
       Object code = __pigeon_list.get(2);
-      pigeonResult.setCode(Code.values()[(int) code]);
+      pigeonResult.setCode((Code) code);
       Object data = __pigeon_list.get(3);
       pigeonResult.setData((Map<String, String>) data);
       return pigeonResult;
     }
   }
 
+  private static class PigeonCodec extends StandardMessageCodec {
+    public static final PigeonCodec INSTANCE = new PigeonCodec();
+
+    private PigeonCodec() {}
+
+    @Override
+    protected Object readValueOfType(byte type, @NonNull ByteBuffer buffer) {
+      switch (type) {
+        case (byte) 129:
+          return MessageData.fromList((ArrayList<Object>) readValue(buffer));
+        case (byte) 130:
+          Object value = readValue(buffer);
+          return value == null ? null : Code.values()[(int) value];
+        default:
+          return super.readValueOfType(type, buffer);
+      }
+    }
+
+    @Override
+    protected void writeValue(@NonNull ByteArrayOutputStream stream, Object value) {
+      if (value instanceof MessageData) {
+        stream.write(129);
+        writeValue(stream, ((MessageData) value).toList());
+      } else if (value instanceof Code) {
+        stream.write(130);
+        writeValue(stream, value == null ? null : ((Code) value).index);
+      } else {
+        super.writeValue(stream, value);
+      }
+    }
+  }
+
   /** Asynchronous error handling return type for non-nullable API method returns. */
   public interface Result<T> {
     /** Success case callback method for handling returns. */
@@ -224,33 +256,6 @@ public interface VoidResult {
     /** Failure case callback method for handling errors. */
     void error(@NonNull Throwable error);
   }
-
-  private static class ExampleHostApiCodec extends StandardMessageCodec {
-    public static final ExampleHostApiCodec INSTANCE = new ExampleHostApiCodec();
-
-    private ExampleHostApiCodec() {}
-
-    @Override
-    protected Object readValueOfType(byte type, @NonNull ByteBuffer buffer) {
-      switch (type) {
-        case (byte) 128:
-          return MessageData.fromList((ArrayList<Object>) readValue(buffer));
-        default:
-          return super.readValueOfType(type, buffer);
-      }
-    }
-
-    @Override
-    protected void writeValue(@NonNull ByteArrayOutputStream stream, Object value) {
-      if (value instanceof MessageData) {
-        stream.write(128);
-        writeValue(stream, ((MessageData) value).toList());
-      } else {
-        super.writeValue(stream, value);
-      }
-    }
-  }
-
   /** Generated interface from Pigeon that represents a handler of messages from Flutter. */
   public interface ExampleHostApi {
 
@@ -264,7 +269,7 @@ public interface ExampleHostApi {
 
     /** The codec used by ExampleHostApi. */
     static @NonNull MessageCodec<Object> getCodec() {
-      return ExampleHostApiCodec.INSTANCE;
+      return PigeonCodec.INSTANCE;
     }
     /** Sets up an instance of `ExampleHostApi` to handle messages through the `binaryMessenger`. */
     static void setUp(@NonNull BinaryMessenger binaryMessenger, @Nullable ExampleHostApi api) {
@@ -382,7 +387,7 @@ public MessageFlutterApi(
     /** Public interface for sending reply. */
     /** The codec used by MessageFlutterApi. */
     static @NonNull MessageCodec<Object> getCodec() {
-      return new StandardMessageCodec();
+      return PigeonCodec.INSTANCE;
     }
 
     public void flutterMethod(@Nullable String aStringArg, @NonNull Result<String> result) {

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

@@ -69,38 +69,45 @@ data class MessageData(
     fun fromList(__pigeon_list: List<Any?>): MessageData {
       val name = __pigeon_list[0] as String?
       val description = __pigeon_list[1] as String?
-      val code = Code.ofRaw(__pigeon_list[2] as Int)!!
+      val code = __pigeon_list[2] as Code
       val data = __pigeon_list[3] as Map<String?, String?>
       return MessageData(name, description, code, data)
     }
   }
 
   fun toList(): List<Any?> {
-    return listOf<Any?>(
+    return listOf(
         name,
         description,
-        code.raw,
+        code,
         data,
     )
   }
 }
 
-private object ExampleHostApiCodec : StandardMessageCodec() {
+private object MessagesPigeonCodec : StandardMessageCodec() {
   override fun readValueOfType(type: Byte, buffer: ByteBuffer): Any? {
     return when (type) {
-      128.toByte() -> {
+      129.toByte() -> {
         return (readValue(buffer) as? List<Any?>)?.let { MessageData.fromList(it) }
       }
+      130.toByte() -> {
+        return (readValue(buffer) as Int?)?.let { Code.ofRaw(it) }
+      }
       else -> super.readValueOfType(type, buffer)
     }
   }
 
   override fun writeValue(stream: ByteArrayOutputStream, value: Any?) {
     when (value) {
       is MessageData -> {
-        stream.write(128)
+        stream.write(129)
         writeValue(stream, value.toList())
       }
+      is Code -> {
+        stream.write(130)
+        writeValue(stream, value.raw)
+      }
       else -> super.writeValue(stream, value)
     }
   }
@@ -116,7 +123,7 @@ interface ExampleHostApi {
 
   companion object {
     /** The codec used by ExampleHostApi. */
-    val codec: MessageCodec<Any?> by lazy { ExampleHostApiCodec }
+    val codec: MessageCodec<Any?> by lazy { MessagesPigeonCodec }
     /** Sets up an instance of `ExampleHostApi` to handle messages through the `binaryMessenger`. */
     @JvmOverloads
     fun setUp(
@@ -136,7 +143,7 @@ interface ExampleHostApi {
           channel.setMessageHandler { _, reply ->
             val wrapped: List<Any?> =
                 try {
-                  listOf<Any?>(api.getHostLanguage())
+                  listOf(api.getHostLanguage())
                 } catch (exception: Throwable) {
                   wrapError(exception)
                 }
@@ -159,7 +166,7 @@ interface ExampleHostApi {
             val bArg = args[1].let { num -> if (num is Int) num.toLong() else num as Long }
             val wrapped: List<Any?> =
                 try {
-                  listOf<Any?>(api.add(aArg, bArg))
+                  listOf(api.add(aArg, bArg))
                 } catch (exception: Throwable) {
                   wrapError(exception)
                 }
@@ -203,7 +210,7 @@ class MessageFlutterApi(
 ) {
   companion object {
     /** The codec used by MessageFlutterApi. */
-    val codec: MessageCodec<Any?> by lazy { StandardMessageCodec() }
+    val codec: MessageCodec<Any?> by lazy { MessagesPigeonCodec }
   }
 
   fun flutterMethod(aStringArg: String?, callback: (Result<String>) -> Unit) {

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

@@ -89,7 +89,7 @@ struct MessageData {
   static func fromList(_ __pigeon_list: [Any?]) -> MessageData? {
     let name: String? = nilOrValue(__pigeon_list[0])
     let description: String? = nilOrValue(__pigeon_list[1])
-    let code = Code(rawValue: __pigeon_list[2] as! Int)!
+    let code = __pigeon_list[2] as! Code
     let data = __pigeon_list[3] as! [String?: String?]
 
     return MessageData(
@@ -103,46 +103,55 @@ struct MessageData {
     return [
       name,
       description,
-      code.rawValue,
+      code,
       data,
     ]
   }
 }
-
-private class ExampleHostApiCodecReader: FlutterStandardReader {
+private class MessagesPigeonCodecReader: FlutterStandardReader {
   override func readValue(ofType type: UInt8) -> Any? {
     switch type {
-    case 128:
+    case 129:
       return MessageData.fromList(self.readValue() as! [Any?])
+    case 130:
+      var enumResult: Code? = nil
+      let enumResultAsInt: Int? = nilOrValue(self.readValue() as? Int)
+      if let enumResultAsInt = enumResultAsInt {
+        enumResult = Code(rawValue: enumResultAsInt)
+      }
+      return enumResult
     default:
       return super.readValue(ofType: type)
     }
   }
 }
 
-private class ExampleHostApiCodecWriter: FlutterStandardWriter {
+private class MessagesPigeonCodecWriter: FlutterStandardWriter {
   override func writeValue(_ value: Any) {
     if let value = value as? MessageData {
-      super.writeByte(128)
+      super.writeByte(129)
       super.writeValue(value.toList())
+    } else if let value = value as? Code {
+      super.writeByte(130)
+      super.writeValue(value.rawValue)
     } else {
       super.writeValue(value)
     }
   }
 }
 
-private class ExampleHostApiCodecReaderWriter: FlutterStandardReaderWriter {
+private class MessagesPigeonCodecReaderWriter: FlutterStandardReaderWriter {
   override func reader(with data: Data) -> FlutterStandardReader {
-    return ExampleHostApiCodecReader(data: data)
+    return MessagesPigeonCodecReader(data: data)
   }
 
   override func writer(with data: NSMutableData) -> FlutterStandardWriter {
-    return ExampleHostApiCodecWriter(data: data)
+    return MessagesPigeonCodecWriter(data: data)
   }
 }
 
-class ExampleHostApiCodec: FlutterStandardMessageCodec {
-  static let shared = ExampleHostApiCodec(readerWriter: ExampleHostApiCodecReaderWriter())
+class MessagesPigeonCodec: FlutterStandardMessageCodec, @unchecked Sendable {
+  static let shared = MessagesPigeonCodec(readerWriter: MessagesPigeonCodecReaderWriter())
 }
 
 /// Generated protocol from Pigeon that represents a handler of messages from Flutter.
@@ -154,8 +163,7 @@ protocol ExampleHostApi {
 
 /// Generated setup class from Pigeon to handle messages through the `binaryMessenger`.
 class ExampleHostApiSetup {
-  /// The codec used by ExampleHostApi.
-  static var codec: FlutterStandardMessageCodec { ExampleHostApiCodec.shared }
+  static var codec: FlutterStandardMessageCodec { MessagesPigeonCodec.shared }
   /// Sets up an instance of `ExampleHostApi` to handle messages through the `binaryMessenger`.
   static func setUp(
     binaryMessenger: FlutterBinaryMessenger, api: ExampleHostApi?, messageChannelSuffix: String = ""
@@ -228,12 +236,16 @@ class MessageFlutterApi: MessageFlutterApiProtocol {
     self.binaryMessenger = binaryMessenger
     self.messageChannelSuffix = messageChannelSuffix.count > 0 ? ".\(messageChannelSuffix)" : ""
   }
+  var codec: MessagesPigeonCodec {
+    return MessagesPigeonCodec.shared
+  }
   func flutterMethod(
     aString aStringArg: String?, completion: @escaping (Result<String, PigeonError>) -> Void
   ) {
     let channelName: String =
       "dev.flutter.pigeon.pigeon_example_package.MessageFlutterApi.flutterMethod\(messageChannelSuffix)"
-    let channel = FlutterBasicMessageChannel(name: channelName, binaryMessenger: binaryMessenger)
+    let channel = FlutterBasicMessageChannel(
+      name: channelName, binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([aStringArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
         completion(.failure(createConnectionError(withChannelName: channelName)))

packages/pigeon/example/app/lib/src/messages.g.dart

@@ -54,7 +54,7 @@ class MessageData {
     return <Object?>[
       name,
       description,
-      code.index,
+      code,
       data,
     ];
   }
@@ -64,19 +64,22 @@ class MessageData {
     return MessageData(
       name: result[0] as String?,
       description: result[1] as String?,
-      code: Code.values[result[2]! as int],
+      code: result[2]! as Code,
       data: (result[3] as Map<Object?, Object?>?)!.cast<String?, String?>(),
     );
   }
 }
 
-class _ExampleHostApiCodec extends StandardMessageCodec {
-  const _ExampleHostApiCodec();
+class _PigeonCodec extends StandardMessageCodec {
+  const _PigeonCodec();
   @override
   void writeValue(WriteBuffer buffer, Object? value) {
     if (value is MessageData) {
-      buffer.putUint8(128);
+      buffer.putUint8(129);
       writeValue(buffer, value.encode());
+    } else if (value is Code) {
+      buffer.putUint8(130);
+      writeValue(buffer, value.index);
     } else {
       super.writeValue(buffer, value);
     }
@@ -85,8 +88,11 @@ class _ExampleHostApiCodec extends StandardMessageCodec {
   @override
   Object? readValueOfType(int type, ReadBuffer buffer) {
     switch (type) {
-      case 128:
+      case 129:
         return MessageData.decode(readValue(buffer)!);
+      case 130:
+        final int? value = readValue(buffer) as int?;
+        return value == null ? null : Code.values[value];
       default:
         return super.readValueOfType(type, buffer);
     }
@@ -104,8 +110,7 @@ class ExampleHostApi {
             messageChannelSuffix.isNotEmpty ? '.$messageChannelSuffix' : '';
   final BinaryMessenger? __pigeon_binaryMessenger;
 
-  static const MessageCodec<Object?> pigeonChannelCodec =
-      _ExampleHostApiCodec();
+  static const MessageCodec<Object?> pigeonChannelCodec = _PigeonCodec();
 
   final String __pigeon_messageChannelSuffix;
 
@@ -198,8 +203,7 @@ class ExampleHostApi {
 }
 
 abstract class MessageFlutterApi {
-  static const MessageCodec<Object?> pigeonChannelCodec =
-      StandardMessageCodec();
+  static const MessageCodec<Object?> pigeonChannelCodec = _PigeonCodec();
 
   String flutterMethod(String? aString);