iOS Background Platform Channels (#29665)

Author: gaaclarke

ci/licenses_golden/licenses_flutter

@@ -1157,8 +1157,6 @@ FILE: ../../../flutter/shell/platform/darwin/ios/framework/Source/connection_col
 FILE: ../../../flutter/shell/platform/darwin/ios/framework/Source/connection_collection_test.mm
 FILE: ../../../flutter/shell/platform/darwin/ios/framework/Source/platform_message_response_darwin.h
 FILE: ../../../flutter/shell/platform/darwin/ios/framework/Source/platform_message_response_darwin.mm
-FILE: ../../../flutter/shell/platform/darwin/ios/framework/Source/platform_message_router.h
-FILE: ../../../flutter/shell/platform/darwin/ios/framework/Source/platform_message_router.mm
 FILE: ../../../flutter/shell/platform/darwin/ios/framework/Source/profiler_metrics_ios.h
 FILE: ../../../flutter/shell/platform/darwin/ios/framework/Source/profiler_metrics_ios.mm
 FILE: ../../../flutter/shell/platform/darwin/ios/framework/Source/vsync_waiter_ios.h
@@ -1190,6 +1188,9 @@ FILE: ../../../flutter/shell/platform/darwin/ios/ios_surface_software.h
 FILE: ../../../flutter/shell/platform/darwin/ios/ios_surface_software.mm
 FILE: ../../../flutter/shell/platform/darwin/ios/ios_switchable_gl_context.h
 FILE: ../../../flutter/shell/platform/darwin/ios/ios_switchable_gl_context.mm
+FILE: ../../../flutter/shell/platform/darwin/ios/platform_message_handler_ios.h
+FILE: ../../../flutter/shell/platform/darwin/ios/platform_message_handler_ios.mm
+FILE: ../../../flutter/shell/platform/darwin/ios/platform_message_handler_ios_test.mm
 FILE: ../../../flutter/shell/platform/darwin/ios/platform_view_ios.h
 FILE: ../../../flutter/shell/platform/darwin/ios/platform_view_ios.mm
 FILE: ../../../flutter/shell/platform/darwin/ios/rendering_api_selection.h

shell/platform/darwin/common/framework/Headers/FlutterBinaryMessenger.h

@@ -31,6 +31,8 @@ typedef void (^FlutterBinaryMessageHandler)(NSData* _Nullable message, FlutterBi
 
 typedef int64_t FlutterBinaryMessengerConnection;
 
+@protocol FlutterTaskQueue;
+
 /**
  * A facility for communicating with the Flutter side using asynchronous message
  * passing with binary messages.
@@ -44,6 +46,16 @@ typedef int64_t FlutterBinaryMessengerConnection;
  */
 FLUTTER_DARWIN_EXPORT
 @protocol FlutterBinaryMessenger <NSObject>
+/// TODO(gaaclarke): Remove optional when macos supports Background Platform Channels.
+@optional
+- (NSObject<FlutterTaskQueue>*)makeBackgroundTaskQueue;
+
+- (FlutterBinaryMessengerConnection)
+ setMessageHandlerOnChannel:(NSString*)channel
+ binaryMessageHandler:(FlutterBinaryMessageHandler _Nullable)handler
+ taskQueue:(NSObject<FlutterTaskQueue>* _Nullable)taskQueue;
+
+@required
 /**
  * Sends a binary message to the Flutter side on the specified channel, expecting
  * no reply.

shell/platform/darwin/common/framework/Headers/FlutterChannels.h

@@ -8,6 +8,8 @@
 #import "FlutterBinaryMessenger.h"
 #import "FlutterCodecs.h"
 
+@protocol FlutterTaskQueue;
+
 NS_ASSUME_NONNULL_BEGIN
 /**
  * A message reply callback.
@@ -24,7 +26,8 @@ typedef void (^FlutterReply)(id _Nullable reply);
  * asynchronous replies back to Flutter.
  *
  * @param message The message.
- * @param callback A callback for submitting a reply to the sender.
+ * @param callback A callback for submitting a reply to the sender which can be invoked from any
+ * thread.
  */
 typedef void (^FlutterMessageHandler)(id _Nullable message, FlutterReply callback);
 
@@ -88,6 +91,27 @@ FLUTTER_DARWIN_EXPORT
  binaryMessenger:(NSObject<FlutterBinaryMessenger>*)messenger
  codec:(NSObject<FlutterMessageCodec>*)codec;
 
+/**
+ * Initializes a `FlutterBasicMessageChannel` with the specified name, binary
+ * messenger, and message codec.
+ *
+ * The channel name logically identifies the channel; identically named channels
+ * interfere with each other's communication.
+ *
+ * The binary messenger is a facility for sending raw, binary messages to the
+ * Flutter side. This protocol is implemented by `FlutterEngine` and `FlutterViewController`.
+ *
+ * @param name The channel name.
+ * @param messenger The binary messenger.
+ * @param codec The message codec.
+ * @param taskQueue The FlutterTaskQueue that executes the handler (see
+ -[FlutterBinaryMessenger makeBackgroundTaskQueue]).
+ */
+- (instancetype)initWithName:(NSString*)name
+ binaryMessenger:(NSObject<FlutterBinaryMessenger>*)messenger
+ codec:(NSObject<FlutterMessageCodec>*)codec
+ taskQueue:(NSObject<FlutterTaskQueue>* _Nullable)taskQueue;
+
 /**
  * Sends the specified message to the Flutter side, ignoring any reply.
  *
@@ -142,7 +166,7 @@ typedef void (^FlutterResult)(id _Nullable result);
  * Invoke the callback with a `FlutterError` to indicate that the call failed.
  * Invoke the callback with `FlutterMethodNotImplemented` to indicate that the
  * method was unknown. Any other values, including `nil`, are interpreted as
- * successful results.
+ * successful results. This can be invoked from any thread.
  */
 typedef void (^FlutterMethodCallHandler)(FlutterMethodCall* call, FlutterResult result);
 
@@ -213,6 +237,27 @@ FLUTTER_DARWIN_EXPORT
  binaryMessenger:(NSObject<FlutterBinaryMessenger>*)messenger
  codec:(NSObject<FlutterMethodCodec>*)codec;
 
+/**
+ * Initializes a `FlutterMethodChannel` with the specified name, binary messenger,
+ * method codec, and task queue.
+ *
+ * The channel name logically identifies the channel; identically named channels
+ * interfere with each other's communication.
+ *
+ * The binary messenger is a facility for sending raw, binary messages to the
+ * Flutter side. This protocol is implemented by `FlutterEngine` and `FlutterViewController`.
+ *
+ * @param name The channel name.
+ * @param messenger The binary messenger.
+ * @param codec The method codec.
+ * @param taskQueue The FlutterTaskQueue that executes the handler (see
+ -[FlutterBinaryMessenger makeBackgroundTaskQueue]).
+ */
+- (instancetype)initWithName:(NSString*)name
+ binaryMessenger:(NSObject<FlutterBinaryMessenger>*)messenger
+ codec:(NSObject<FlutterMethodCodec>*)codec
+ taskQueue:(NSObject<FlutterTaskQueue>* _Nullable)taskQueue;
+
 // clang-format off
 /**
  * Invokes the specified Flutter method with the specified arguments, expecting
@@ -371,6 +416,27 @@ FLUTTER_DARWIN_EXPORT
 - (instancetype)initWithName:(NSString*)name
  binaryMessenger:(NSObject<FlutterBinaryMessenger>*)messenger
  codec:(NSObject<FlutterMethodCodec>*)codec;
+
+/**
+ * Initializes a `FlutterEventChannel` with the specified name, binary messenger,
+ * method codec and task queue.
+ *
+ * The channel name logically identifies the channel; identically named channels
+ * interfere with each other's communication.
+ *
+ * The binary messenger is a facility for sending raw, binary messages to the
+ * Flutter side. This protocol is implemented by `FlutterEngine` and `FlutterViewController`.
+ *
+ * @param name The channel name.
+ * @param messenger The binary messenger.
+ * @param codec The method codec.
+ * @param taskQueue The FlutterTaskQueue that executes the handler (see
+ -[FlutterBinaryMessenger makeBackgroundTaskQueue]).
+ */
+- (instancetype)initWithName:(NSString*)name
+ binaryMessenger:(NSObject<FlutterBinaryMessenger>*)messenger
+ codec:(NSObject<FlutterMethodCodec>*)codec
+ taskQueue:(NSObject<FlutterTaskQueue>* _Nullable)taskQueue;
 /**
  * Registers a handler for stream setup requests from the Flutter side.
  *

shell/platform/darwin/common/framework/Source/FlutterChannels.mm

@@ -16,11 +16,30 @@ static void ResizeChannelBuffer(NSObject<FlutterBinaryMessenger>* binaryMessenge
  [binaryMessenger sendOnChannel:FlutterChannelBuffersChannel message:message];
 }
 
+static FlutterBinaryMessengerConnection SetMessageHandler(
+ NSObject<FlutterBinaryMessenger>* messenger,
+ NSString* name,
+ FlutterBinaryMessageHandler handler,
+ NSObject<FlutterTaskQueue>* taskQueue) {
+ if (taskQueue) {
+ NSCAssert([messenger respondsToSelector:@selector(setMessageHandlerOnChannel:
+ binaryMessageHandler:taskQueue:)],
+ @"");
+ return [messenger setMessageHandlerOnChannel:name
+ binaryMessageHandler:handler
+ taskQueue:taskQueue];
+ } else {
+ return [messenger setMessageHandlerOnChannel:name binaryMessageHandler:handler];
+ }
+}
+
+////////////////////////////////////////////////////////////////////////////////
 @implementation FlutterBasicMessageChannel {
  NSObject<FlutterBinaryMessenger>* _messenger;
  NSString* _name;
  NSObject<FlutterMessageCodec>* _codec;
  FlutterBinaryMessengerConnection _connection;
+ NSObject<FlutterTaskQueue>* _taskQueue;
 }
 + (instancetype)messageChannelWithName:(NSString*)name
  binaryMessenger:(NSObject<FlutterBinaryMessenger>*)messenger {
@@ -40,18 +59,28 @@ + (instancetype)messageChannelWithName:(NSString*)name
 - (instancetype)initWithName:(NSString*)name
  binaryMessenger:(NSObject<FlutterBinaryMessenger>*)messenger
  codec:(NSObject<FlutterMessageCodec>*)codec {
+ self = [self initWithName:name binaryMessenger:messenger codec:codec taskQueue:nil];
+ return self;
+}
+
+- (instancetype)initWithName:(NSString*)name
+ binaryMessenger:(NSObject<FlutterBinaryMessenger>*)messenger
+ codec:(NSObject<FlutterMessageCodec>*)codec
+ taskQueue:(NSObject<FlutterTaskQueue>*)taskQueue {
  self = [super init];
  NSAssert(self, @"Super init cannot be nil");
  _name = [name retain];
  _messenger = [messenger retain];
  _codec = [codec retain];
+ _taskQueue = [taskQueue retain];
  return self;
 }
 
 - (void)dealloc {
  [_name release];
  [_messenger release];
  [_codec release];
+ [_taskQueue release];
  [super dealloc];
 }
 
@@ -85,7 +114,7 @@ - (void)setMessageHandler:(FlutterMessageHandler)handler {
  callback([codec encode:reply]);
  });
  };
- _connection = [_messenger setMessageHandlerOnChannel:_name binaryMessageHandler:messageHandler];
+ _connection = SetMessageHandler(_messenger, _name, messageHandler, _taskQueue);
 }
 
 - (void)resizeChannelBuffer:(NSInteger)newSize {
@@ -96,6 +125,7 @@ - (void)resizeChannelBuffer:(NSInteger)newSize {
 
 #pragma mark - Method channel
 
+////////////////////////////////////////////////////////////////////////////////
 @implementation FlutterError
 + (instancetype)errorWithCode:(NSString*)code message:(NSString*)message details:(id)details {
  return [[[FlutterError alloc] initWithCode:code message:message details:details] autorelease];
@@ -136,6 +166,7 @@ - (NSUInteger)hash {
 }
 @end
 
+////////////////////////////////////////////////////////////////////////////////
 @implementation FlutterMethodCall
 + (instancetype)methodCallWithMethodName:(NSString*)method arguments:(id)arguments {
  return [[[FlutterMethodCall alloc] initWithMethodName:method arguments:arguments] autorelease];
@@ -175,11 +206,13 @@ - (NSUInteger)hash {
 
 NSObject const* FlutterMethodNotImplemented = [[NSObject alloc] init];
 
+////////////////////////////////////////////////////////////////////////////////
 @implementation FlutterMethodChannel {
  NSObject<FlutterBinaryMessenger>* _messenger;
  NSString* _name;
  NSObject<FlutterMethodCodec>* _codec;
  FlutterBinaryMessengerConnection _connection;
+ NSObject<FlutterTaskQueue>* _taskQueue;
 }
 
 + (instancetype)methodChannelWithName:(NSString*)name
@@ -198,18 +231,27 @@ + (instancetype)methodChannelWithName:(NSString*)name
 - (instancetype)initWithName:(NSString*)name
  binaryMessenger:(NSObject<FlutterBinaryMessenger>*)messenger
  codec:(NSObject<FlutterMethodCodec>*)codec {
+ self = [self initWithName:name binaryMessenger:messenger codec:codec taskQueue:nil];
+ return self;
+}
+- (instancetype)initWithName:(NSString*)name
+ binaryMessenger:(NSObject<FlutterBinaryMessenger>*)messenger
+ codec:(NSObject<FlutterMethodCodec>*)codec
+ taskQueue:(NSObject<FlutterTaskQueue>*)taskQueue {
  self = [super init];
  NSAssert(self, @"Super init cannot be nil");
  _name = [name retain];
  _messenger = [messenger retain];
  _codec = [codec retain];
+ _taskQueue = [taskQueue retain];
  return self;
 }
 
 - (void)dealloc {
  [_name release];
  [_messenger release];
  [_codec release];
+ [_taskQueue release];
  [super dealloc];
 }
 
@@ -256,7 +298,7 @@ - (void)setMethodCallHandler:(FlutterMethodCallHandler)handler {
  }
  });
  };
- _connection = [_messenger setMessageHandlerOnChannel:_name binaryMessageHandler:messageHandler];
+ _connection = SetMessageHandler(_messenger, _name, messageHandler, _taskQueue);
 }
 
 - (void)resizeChannelBuffer:(NSInteger)newSize {
@@ -269,10 +311,13 @@ - (void)resizeChannelBuffer:(NSInteger)newSize {
 
 NSObject const* FlutterEndOfEventStream = [[NSObject alloc] init];
 
+////////////////////////////////////////////////////////////////////////////////
 @implementation FlutterEventChannel {
  NSObject<FlutterBinaryMessenger>* _messenger;
  NSString* _name;
  NSObject<FlutterMethodCodec>* _codec;
+ NSObject<FlutterTaskQueue>* _taskQueue;
+ FlutterBinaryMessengerConnection _connection;
 }
 + (instancetype)eventChannelWithName:(NSString*)name
  binaryMessenger:(NSObject<FlutterBinaryMessenger>*)messenger {
@@ -290,25 +335,36 @@ + (instancetype)eventChannelWithName:(NSString*)name
 - (instancetype)initWithName:(NSString*)name
  binaryMessenger:(NSObject<FlutterBinaryMessenger>*)messenger
  codec:(NSObject<FlutterMethodCodec>*)codec {
+ return [self initWithName:name binaryMessenger:messenger codec:codec taskQueue:nil];
+}
+
+- (instancetype)initWithName:(NSString*)name
+ binaryMessenger:(NSObject<FlutterBinaryMessenger>*)messenger
+ codec:(NSObject<FlutterMethodCodec>*)codec
+ taskQueue:(NSObject<FlutterTaskQueue>* _Nullable)taskQueue {
  self = [super init];
  NSAssert(self, @"Super init cannot be nil");
  _name = [name retain];
  _messenger = [messenger retain];
  _codec = [codec retain];
+ _taskQueue = [taskQueue retain];
  return self;
 }
 
 - (void)dealloc {
  [_name release];
  [_codec release];
  [_messenger release];
+ [_taskQueue release];
  [super dealloc];
 }
 
-static void SetStreamHandlerMessageHandlerOnChannel(NSObject<FlutterStreamHandler>* handler,
- NSString* name,
- NSObject<FlutterBinaryMessenger>* messenger,
- NSObject<FlutterMethodCodec>* codec) {
+static FlutterBinaryMessengerConnection SetStreamHandlerMessageHandlerOnChannel(
+ NSObject<FlutterStreamHandler>* handler,
+ NSString* name,
+ NSObject<FlutterBinaryMessenger>* messenger,
+ NSObject<FlutterMethodCodec>* codec,
+ NSObject<FlutterTaskQueue>* taskQueue) {
  __block FlutterEventSink currentSink = nil;
  FlutterBinaryMessageHandler messageHandler = ^(NSData* message, FlutterBinaryReply callback) {
  FlutterMethodCall* call = [codec decodeMethodCall:message];
@@ -354,14 +410,16 @@ static void SetStreamHandlerMessageHandlerOnChannel(NSObject<FlutterStreamHandle
  callback(nil);
  }
  };
- [messenger setMessageHandlerOnChannel:name binaryMessageHandler:messageHandler];
+ return SetMessageHandler(messenger, name, messageHandler, taskQueue);
 }
 
 - (void)setStreamHandler:(NSObject<FlutterStreamHandler>*)handler {
  if (!handler) {
- [_messenger setMessageHandlerOnChannel:_name binaryMessageHandler:nil];
+ [_messenger cleanUpConnection:_connection];
+ _connection = 0;
  return;
  }
- SetStreamHandlerMessageHandlerOnChannel(handler, _name, _messenger, _codec);
+ _connection =
+ SetStreamHandlerMessageHandlerOnChannel(handler, _name, _messenger, _codec, _taskQueue);
 }
 @end