notif ios: Buffer notification tap events; same as on Android

It turns out that
`userNotificationCenter(_:didReceive:withCompletionHandler:)`
does execute when app is terminated and later opened by
tapping on a notification, so there is no need to check
`launchOptions` in `application(_:didFinishLaunchingWithOptions:)`
to handle this case.

But because we currently handle both cases, there is a potential
bug where if both are handled, it could cause double navigations
for the same notification. This is not observed in practice,
probably because we do not buffer events from
`userNotificationCenter(_:didReceive:withCompletionHandler:)`
currently and those events may be missed until Flutter init is
complete and the handler (in NotificationOpenService.init) is
setup.

So, remove the unnecessary handlers for `launchOptions`. This also
unifies our notification opening implementation between Android and
iOS, where we handle all types of notification tap events via the
same Pigeon EventChannel API.

Author: rajveermalviya

android/app/src/main/kotlin/com/zulip/flutter/notifications/Notifications.g.kt

@@ -14,26 +14,6 @@ import io.flutter.plugin.common.StandardMessageCodec
 import java.io.ByteArrayOutputStream
 import java.nio.ByteBuffer
 private object NotificationsPigeonUtils {
-
-  fun wrapResult(result: Any?): List<Any?> {
-    return listOf(result)
-  }
-
-  fun wrapError(exception: Throwable): List<Any?> {
-    return if (exception is FlutterError) {
-      listOf(
-        exception.code,
-        exception.message,
-        exception.details
-      )
-    } else {
-      listOf(
-        exception.javaClass.simpleName,
-        exception.toString(),
-        "Cause: " + exception.cause + ", Stacktrace: " + Log.getStackTraceString(exception)
-      )
-    }
-  }
   fun deepEquals(a: Any?, b: Any?): Boolean {
     if (a is ByteArray && b is ByteArray) {
         return a.contentEquals(b)
@@ -78,40 +58,6 @@ class FlutterError (
   val details: Any? = null
 ) : Throwable()
 
-/** Generated class from Pigeon that represents data sent in messages. */
-data class NotificationDataFromLaunch (
-  /**
-   * The raw payload that is attached to the notification,
-   * holding the information required to carry out the navigation.
-   *
-   * See [NotificationHostApi.getNotificationDataFromLaunch].
-   */
-  val payload: Map<Any?, Any?>
-)
- {
-  companion object {
-    fun fromList(pigeonVar_list: List<Any?>): NotificationDataFromLaunch {
-      val payload = pigeonVar_list[0] as Map<Any?, Any?>
-      return NotificationDataFromLaunch(payload)
-    }
-  }
-  fun toList(): List<Any?> {
-    return listOf(
-      payload,
-    )
-  }
-  override fun equals(other: Any?): Boolean {
-    if (other !is NotificationDataFromLaunch) {
-      return false
-    }
-    if (this === other) {
-      return true
-    }
-    return NotificationsPigeonUtils.deepEquals(toList(), other.toList())  }
-
-  override fun hashCode(): Int = toList().hashCode()
-}
-
 /**
  * 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.
@@ -202,16 +148,11 @@ private open class NotificationsPigeonCodec : StandardMessageCodec() {
   override fun readValueOfType(type: Byte, buffer: ByteBuffer): Any? {
     return when (type) {
       129.toByte() -> {
-        return (readValue(buffer) as? List<Any?>)?.let {
-          NotificationDataFromLaunch.fromList(it)
-        }
-      }
-      130.toByte() -> {
         return (readValue(buffer) as? List<Any?>)?.let {
           IosNotificationTapEvent.fromList(it)
         }
       }
-      131.toByte() -> {
+      130.toByte() -> {
         return (readValue(buffer) as? List<Any?>)?.let {
           AndroidNotificationTapEvent.fromList(it)
         }
@@ -221,16 +162,12 @@ private open class NotificationsPigeonCodec : StandardMessageCodec() {
   }
   override fun writeValue(stream: ByteArrayOutputStream, value: Any?)   {
     when (value) {
-      is NotificationDataFromLaunch -> {
-        stream.write(129)
-        writeValue(stream, value.toList())
-      }
       is IosNotificationTapEvent -> {
-        stream.write(130)
+        stream.write(129)
         writeValue(stream, value.toList())
       }
       is AndroidNotificationTapEvent -> {
-        stream.write(131)
+        stream.write(130)
         writeValue(stream, value.toList())
       }
       else -> super.writeValue(stream, value)
@@ -240,46 +177,6 @@ private open class NotificationsPigeonCodec : StandardMessageCodec() {
 
 val NotificationsPigeonMethodCodec = StandardMethodCodec(NotificationsPigeonCodec())
 
-/** Generated interface from Pigeon that represents a handler of messages from Flutter. */
-interface NotificationHostApi {
-  /**
-   * Retrieves notification data if the app was launched by tapping on a notification.
-   *
-   * Returns `launchOptions.remoteNotification`,
-   * which is the raw APNs data dictionary
-   * if the app launch was opened by a notification tap,
-   * else null. See Apple doc:
-   *   https://developer.apple.com/documentation/uikit/uiapplication/launchoptionskey/remotenotification
-   */
-  fun getNotificationDataFromLaunch(): NotificationDataFromLaunch?
-
-  companion object {
-    /** The codec used by NotificationHostApi. */
-    val codec: MessageCodec<Any?> by lazy {
-      NotificationsPigeonCodec()
-    }
-    /** Sets up an instance of `NotificationHostApi` to handle messages through the `binaryMessenger`. */
-    @JvmOverloads
-    fun setUp(binaryMessenger: BinaryMessenger, api: NotificationHostApi?, messageChannelSuffix: String = "") {
-      val separatedMessageChannelSuffix = if (messageChannelSuffix.isNotEmpty()) ".$messageChannelSuffix" else ""
-      run {
-        val channel = BasicMessageChannel<Any?>(binaryMessenger, "dev.flutter.pigeon.zulip.NotificationHostApi.getNotificationDataFromLaunch$separatedMessageChannelSuffix", codec)
-        if (api != null) {
-          channel.setMessageHandler { _, reply ->
-            val wrapped: List<Any?> = try {
-              listOf(api.getNotificationDataFromLaunch())
-            } catch (exception: Throwable) {
-              NotificationsPigeonUtils.wrapError(exception)
-            }
-            reply.reply(wrapped)
-          }
-        } else {
-          channel.setMessageHandler(null)
-        }
-      }
-    }
-  }
-}
 
 private class NotificationsPigeonStreamHandler<T>(
     val wrapper: NotificationsPigeonEventChannelWrapper<T>

ios/Runner/AppDelegate.swift

@@ -20,18 +20,6 @@ import UIKit
 
     IosNativeHostApiSetup.setUp(binaryMessenger: controller.binaryMessenger, api: IosNativeHostApiImpl())
 
-    // Retrieve the remote notification payload from launch options;
-    // this will be null if the launch wasn't triggered by a notification.
-    let notificationPayload =
-      launchOptions?[.remoteNotification] as? [AnyHashable: Any]
-    let api = NotificationHostApiImpl(
-      notificationPayload.map { NotificationDataFromLaunch(payload: $0) }
-    )
-    NotificationHostApiSetup.setUp(
-      binaryMessenger: controller.binaryMessenger,
-      api: api
-    )
-
     notificationTapEventListener = NotificationTapEventListener()
     NotificationTapEventsStreamHandler.register(
       with: controller.binaryMessenger,
@@ -58,16 +46,3 @@ import UIKit
     completionHandler()
   }
 }
-
-private class NotificationHostApiImpl: NotificationHostApi {
-  private let maybeDataFromLaunch: NotificationDataFromLaunch?
-
-  init(_ maybeDataFromLaunch: NotificationDataFromLaunch?) {
-    self.maybeDataFromLaunch = maybeDataFromLaunch
-  }
-
-  func getNotificationDataFromLaunch() -> NotificationDataFromLaunch? {
-    maybeDataFromLaunch
-  }
-}
-

ios/Runner/NotificationTapEventListener.swift

@@ -5,15 +5,34 @@ import UIKit
 //   https://github.com/flutter/packages/blob/2dff6213a/packages/pigeon/example/app/ios/Runner/AppDelegate.swift#L49-L74
 class NotificationTapEventListener: NotificationTapEventsStreamHandler {
   var eventSink: PigeonEventSink<NotificationTapEvent>?
+  var buffer: [NotificationTapEvent] = []
 
   override func onListen(
     withArguments arguments: Any?,
     sink: PigeonEventSink<NotificationTapEvent>
   ) {
     eventSink = sink
+    if !buffer.isEmpty {
+      buffer.forEach {
+        sink.success($0)
+      }
+      buffer.removeAll()
+    }
+  }
+
+  override func onCancel(withArguments arguments: Any?) {
+    if let eventSink = self.eventSink {
+      eventSink.endOfStream()
+      self.eventSink = nil
+    }
   }
 
   func onNotificationTapEvent(payload: [AnyHashable: Any]) {
-    eventSink?.success(IosNotificationTapEvent(payload: payload))
+    let event = IosNotificationTapEvent(payload: payload)
+    if let eventSink = self.eventSink {
+      eventSink.success(event)
+    } else {
+      buffer.append(event)
+    }
   }
 }

ios/Runner/Notifications.g.swift

@@ -29,32 +29,6 @@ final class PigeonError: Error {
   }
 }
 
-private func wrapResult(_ result: Any?) -> [Any?] {
-  return [result]
-}
-
-private func wrapError(_ error: Any) -> [Any?] {
-  if let pigeonError = error as? PigeonError {
-    return [
-      pigeonError.code,
-      pigeonError.message,
-      pigeonError.details,
-    ]
-  }
-  if let flutterError = error as? FlutterError {
-    return [
-      flutterError.code,
-      flutterError.message,
-      flutterError.details,
-    ]
-  }
-  return [
-    "\(error)",
-    "\(type(of: error))",
-    "Stacktrace: \(Thread.callStackSymbols)",
-  ]
-}
-
 private func isNullish(_ value: Any?) -> Bool {
   return value is NSNull || value == nil
 }
@@ -128,35 +102,6 @@ func deepHashNotifications(value: Any?, hasher: inout Hasher) {
 
 
 
-/// Generated class from Pigeon that represents data sent in messages.
-struct NotificationDataFromLaunch: Hashable {
-  /// The raw payload that is attached to the notification,
-  /// holding the information required to carry out the navigation.
-  ///
-  /// See [NotificationHostApi.getNotificationDataFromLaunch].
-  var payload: [AnyHashable?: Any?]
-
-
-  // swift-format-ignore: AlwaysUseLowerCamelCase
-  static func fromList(_ pigeonVar_list: [Any?]) -> NotificationDataFromLaunch? {
-    let payload = pigeonVar_list[0] as! [AnyHashable?: Any?]
-
-    return NotificationDataFromLaunch(
-      payload: payload
-    )
-  }
-  func toList() -> [Any?] {
-    return [
-      payload
-    ]
-  }
-  static func == (lhs: NotificationDataFromLaunch, rhs: NotificationDataFromLaunch) -> Bool {
-    return deepEqualsNotifications(lhs.toList(), rhs.toList())  }
-  func hash(into hasher: inout Hasher) {
-    deepHashNotifications(value: toList(), hasher: &hasher)
-  }
-}
-
 /// Generated class from Pigeon that represents data sent in messages.
 /// This protocol should not be extended by any user class outside of the generated file.
 protocol NotificationTapEvent {
@@ -235,10 +180,8 @@ private class NotificationsPigeonCodecReader: FlutterStandardReader {
   override func readValue(ofType type: UInt8) -> Any? {
     switch type {
     case 129:
-      return NotificationDataFromLaunch.fromList(self.readValue() as! [Any?])
-    case 130:
       return IosNotificationTapEvent.fromList(self.readValue() as! [Any?])
-    case 131:
+    case 130:
       return AndroidNotificationTapEvent.fromList(self.readValue() as! [Any?])
     default:
       return super.readValue(ofType: type)
@@ -248,14 +191,11 @@ private class NotificationsPigeonCodecReader: FlutterStandardReader {
 
 private class NotificationsPigeonCodecWriter: FlutterStandardWriter {
   override func writeValue(_ value: Any) {
-    if let value = value as? NotificationDataFromLaunch {
+    if let value = value as? IosNotificationTapEvent {
       super.writeByte(129)
       super.writeValue(value.toList())
-    } else if let value = value as? IosNotificationTapEvent {
-      super.writeByte(130)
-      super.writeValue(value.toList())
     } else if let value = value as? AndroidNotificationTapEvent {
-      super.writeByte(131)
+      super.writeByte(130)
       super.writeValue(value.toList())
     } else {
       super.writeValue(value)
@@ -279,46 +219,6 @@ class NotificationsPigeonCodec: FlutterStandardMessageCodec, @unchecked Sendable
 
 var notificationsPigeonMethodCodec = FlutterStandardMethodCodec(readerWriter: NotificationsPigeonCodecReaderWriter());
 
-/// Generated protocol from Pigeon that represents a handler of messages from Flutter.
-protocol NotificationHostApi {
-  /// Retrieves notification data if the app was launched by tapping on a notification.
-  ///
-  /// Returns `launchOptions.remoteNotification`,
-  /// which is the raw APNs data dictionary
-  /// if the app launch was opened by a notification tap,
-  /// else null. See Apple doc:
-  ///   https://developer.apple.com/documentation/uikit/uiapplication/launchoptionskey/remotenotification
-  func getNotificationDataFromLaunch() throws -> NotificationDataFromLaunch?
-}
-
-/// Generated setup class from Pigeon to handle messages through the `binaryMessenger`.
-class NotificationHostApiSetup {
-  static var codec: FlutterStandardMessageCodec { NotificationsPigeonCodec.shared }
-  /// Sets up an instance of `NotificationHostApi` to handle messages through the `binaryMessenger`.
-  static func setUp(binaryMessenger: FlutterBinaryMessenger, api: NotificationHostApi?, messageChannelSuffix: String = "") {
-    let channelSuffix = messageChannelSuffix.count > 0 ? ".\(messageChannelSuffix)" : ""
-    /// Retrieves notification data if the app was launched by tapping on a notification.
-    ///
-    /// Returns `launchOptions.remoteNotification`,
-    /// which is the raw APNs data dictionary
-    /// if the app launch was opened by a notification tap,
-    /// else null. See Apple doc:
-    ///   https://developer.apple.com/documentation/uikit/uiapplication/launchoptionskey/remotenotification
-    let getNotificationDataFromLaunchChannel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.zulip.NotificationHostApi.getNotificationDataFromLaunch\(channelSuffix)", binaryMessenger: binaryMessenger, codec: codec)
-    if let api = api {
-      getNotificationDataFromLaunchChannel.setMessageHandler { _, reply in
-        do {
-          let result = try api.getNotificationDataFromLaunch()
-          reply(wrapResult(result))
-        } catch {
-          reply(wrapError(error))
-        }
-      }
-    } else {
-      getNotificationDataFromLaunchChannel.setMessageHandler(nil)
-    }
-  }
-}
 
 private class PigeonStreamHandler<ReturnType>: NSObject, FlutterStreamHandler {
   private let wrapper: PigeonEventChannelWrapper<ReturnType>