Migrate Clipboard to platform messages (#6367)

The platform plugin now supports clipboard operations.

packages/flutter/lib/src/material/text_selection.dart

@@ -50,7 +50,7 @@ class _TextSelectionToolbar extends StatelessWidget {
   }
 
   void _handleCut() {
-    Clipboard.setClipboardData(new ClipboardData()..text = value.selection.textInside(value.text));
+    Clipboard.setData(new ClipboardData(text: value.selection.textInside(value.text)));
     delegate.inputValue = new InputValue(
       text: value.selection.textBefore(value.text) + value.selection.textAfter(value.text),
       selection: new TextSelection.collapsed(offset: value.selection.start)
@@ -59,7 +59,7 @@ class _TextSelectionToolbar extends StatelessWidget {
   }
 
   void _handleCopy() {
-    Clipboard.setClipboardData(new ClipboardData()..text = value.selection.textInside(value.text));
+    Clipboard.setData(new ClipboardData(text: value.selection.textInside(value.text)));
     delegate.inputValue = new InputValue(
       text: value.text,
       selection: new TextSelection.collapsed(offset: value.selection.end)
@@ -69,11 +69,11 @@ class _TextSelectionToolbar extends StatelessWidget {
 
   Future<Null> _handlePaste() async {
     InputValue value = this.value;  // Snapshot the input before using `await`.
-    ClipboardData clip = await Clipboard.getClipboardData(Clipboard.kTextPlain);
-    if (clip != null) {
+    ClipboardData data = await Clipboard.getData(Clipboard.kTextPlain);
+    if (data != null) {
       delegate.inputValue = new InputValue(
-        text: value.selection.textBefore(value.text) + clip.text + value.selection.textAfter(value.text),
-        selection: new TextSelection.collapsed(offset: value.selection.start + clip.text.length)
+        text: value.selection.textBefore(value.text) + data.text + value.selection.textAfter(value.text),
+        selection: new TextSelection.collapsed(offset: value.selection.start + data.text.length)
       );
     }
     delegate.hideToolbar();

packages/flutter/lib/src/services/clipboard.dart

@@ -4,38 +4,48 @@
 
 import 'dart:async';
 
-import 'package:flutter_services/editing.dart' as mojom;
-
-import 'shell.dart';
-
-export 'package:flutter_services/editing.dart' show ClipboardData;
-
-mojom.ClipboardProxy _initClipboardProxy() {
-  return shell.connectToApplicationService('mojo:clipboard', mojom.Clipboard.connectToService);
+import 'platform_messages.dart';
+
+/// Data stored on the system clip board.
+///
+/// The system clip board can contain data of various media types. This data
+/// structure currently supports only plain text data in the [text] property.
+class ClipboardData {
+  /// Creates data for the system clipboard.
+  const ClipboardData({ this.text });
+
+  /// Plain text data on the clip board.
+  final String text;
 }
 
-final mojom.ClipboardProxy _clipboardProxy = _initClipboardProxy();
-
-/// An interface to the system's clipboard. Wraps the mojo interface.
+/// An interface to the system's clipboard.
 class Clipboard {
-  /// Constants for common [getClipboardData] [format] types.
+  /// Constants for common [getData] [format] types.
   static final String kTextPlain = 'text/plain';
 
   Clipboard._();
 
   /// Stores the given clipboard data on the clipboard.
-  static void setClipboardData(mojom.ClipboardData clip) {
-    _clipboardProxy.setClipboardData(clip);
+  static Future<Null> setData(ClipboardData data) async {
+    await PlatformMessages.sendJSON('flutter/platform', <String, dynamic>{
+      'method': 'Clipboard.setData',
+      'args': <Map<String, dynamic>>[<String, dynamic>{
+        'text': data.text,
+      }],
+    });
   }
 
   /// Retrieves data from the clipboard that matches the given format.
   ///
   ///  * `format` is a media type, such as `text/plain`.
-  static Future<mojom.ClipboardData> getClipboardData(String format) {
-    Completer<mojom.ClipboardData> completer = new Completer<mojom.ClipboardData>();
-    _clipboardProxy.getClipboardData(format, (mojom.ClipboardData clip) {
-      completer.complete(clip);
+  static Future<ClipboardData> getData(String format) async {
+    Map<String, dynamic> result =
+        await PlatformMessages.sendJSON('flutter/platform', <String, dynamic>{
+      'method': 'Clipboard.getData',
+      'args': <String>[format],
     });
-    return completer.future;
+    if (result == null)
+      return null;
+    return new ClipboardData(text: result['text']);
   }
 }

packages/flutter/lib/src/services/platform_messages.dart

@@ -28,29 +28,35 @@ dynamic _decodeJSON(String message) {
   return message != null ? JSON.decode(message) : null;
 }
 
-void _sendString(String name, String message, void callback(String reply)) {
-  Uint8List encoded = UTF8.encoder.convert(message);
-  ui.window.sendPlatformMessage(name, encoded.buffer.asByteData(), (ByteData reply) {
-    try {
-      callback(_decodeUTF8(reply));
-    } catch (exception, stack) {
-      FlutterError.reportError(new FlutterErrorDetails(
-        exception: exception,
-        stack: stack,
-        library: 'services library',
-        context: 'during a platform message response callback',
-      ));
-    }
-  });
-}
-
 typedef Future<ByteData> _PlatformMessageHandler(ByteData message);
 
 /// Sends message to and receives messages from the underlying platform.
 class PlatformMessages {
+  /// Handlers for incoming platform messages.
   static final Map<String, _PlatformMessageHandler> _handlers =
       <String, _PlatformMessageHandler>{};
 
+  /// Mock handlers that intercept and respond to outgoing messages.
+  static final Map<String, _PlatformMessageHandler> _mockHandlers =
+      <String, _PlatformMessageHandler>{};
+
+  static Future<ByteData> _sendPlatformMessage(String name, ByteData message) {
+    final Completer<ByteData> completer = new Completer<ByteData>();
+    ui.window.sendPlatformMessage(name, message, (ByteData reply) {
+      try {
+        completer.complete(reply);
+      } catch (exception, stack) {
+        FlutterError.reportError(new FlutterErrorDetails(
+          exception: exception,
+          stack: stack,
+          library: 'services library',
+          context: 'during a platform message response callback',
+        ));
+      }
+    });
+    return completer.future;
+  }
+
   /// Calls the handler registered for the given name.
   ///
   /// Typically called by [ServicesBinding] to handle platform messages received
@@ -77,22 +83,22 @@ class PlatformMessages {
     }
   }
 
+  /// Send a binary message to the host application.
+  static Future<ByteData> sendBinary(String name, ByteData message) {
+    final _PlatformMessageHandler handler = _mockHandlers[name];
+    if (handler != null)
+      return handler(message);
+    return _sendPlatformMessage(name, message);
+  }
+
   /// Send a string message to the host application.
-  static Future<String> sendString(String name, String message) {
-    Completer<String> completer = new Completer<String>();
-    _sendString(name, message, (String reply) {
-      completer.complete(reply);
-    });
-    return completer.future;
+  static Future<String> sendString(String name, String message) async {
+    return _decodeUTF8(await sendBinary(name, _encodeUTF8(message)));
   }
 
   /// Sends a JSON-encoded message to the host application and JSON-decodes the response.
-  static Future<dynamic> sendJSON(String name, dynamic json) {
-    Completer<dynamic> completer = new Completer<dynamic>();
-    _sendString(name, JSON.encode(json), (String reply) {
-      completer.complete(_decodeJSON(reply));
-    });
-    return completer.future;
+  static Future<dynamic> sendJSON(String name, dynamic json) async {
+    return _decodeJSON(await sendString(name, _encodeJSON(json)));
   }
 
   /// Set a callback for receiving binary messages from the platform.
@@ -123,4 +129,35 @@ class PlatformMessages {
       return _encodeJSON(await handler(_decodeJSON(message)));
     });
   }
+
+  /// Sets a message handler that intercepts outgoing messages in binary form.
+  ///
+  /// The given callback will replace the currently registered callback (if any).
+  /// To remove the mock handler, pass `null` as the `handler` argument.
+  static void setMockBinaryMessageHandler(String name, Future<ByteData> handler(ByteData message)) {
+    if (handler == null)
+      _mockHandlers.remove(handler);
+    else
+      _mockHandlers[name] = handler;
+  }
+
+  /// Sets a message handler that intercepts outgoing messages in string form.
+  ///
+  /// The given callback will replace the currently registered callback (if any).
+  /// To remove the mock handler, pass `null` as the `handler` argument.
+  static void setMockStringMessageHandler(String name, Future<String> handler(String message)) {
+    setMockBinaryMessageHandler(name, (ByteData message) async {
+      return _encodeUTF8(await handler(_decodeUTF8(message)));
+    });
+  }
+
+  /// Sets a message handler that intercepts outgoing messages in JSON form.
+  ///
+  /// The given callback will replace the currently registered callback (if any).
+  /// To remove the mock handler, pass `null` as the `handler` argument.
+  static void setMockJSONMessageHandler(String name, Future<dynamic> handler(dynamic message)) {
+    setMockStringMessageHandler(name, (String message) async {
+      return _encodeJSON(await handler(_decodeJSON(message)));
+    });
+  }
 }

packages/flutter/test/widget/input_test.dart

@@ -7,6 +7,7 @@ import 'dart:async';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/rendering.dart';
+import 'package:flutter/services.dart';
 import 'package:flutter_services/editing.dart' as mojom;
 import 'package:meta/meta.dart';
 
@@ -30,29 +31,30 @@ class MockKeyboard extends mojom.KeyboardProxy {
   void setEditingState(mojom.EditingState state) {}
 }
 
-class MockClipboard extends mojom.ClipboardProxy {
-  MockClipboard() : super.unbound();
-
-  mojom.ClipboardData _clip;
-
-  @override
-  void setClipboardData(mojom.ClipboardData clip) {
-    _clip = clip;
-  }
-
-  @override
-  void getClipboardData(String format, void callback(mojom.ClipboardData clip)) {
-    scheduleMicrotask(() {
-      callback(_clip);
-    });
+class MockClipboard {
+  Object _clipboardData = <String, dynamic>{
+    'text': null
+  };
+
+  Future<dynamic> handleJSONMessage(dynamic json) async {
+    final String method = json['method'];
+    final List<dynamic> args= json['args'];
+    switch (method) {
+      case 'Clipboard.getData':
+        return _clipboardData;
+      case 'Clipboard.setData':
+        _clipboardData = args[0];
+        break;
+    }
   }
 }
 
 void main() {
   MockKeyboard mockKeyboard = new MockKeyboard();
   serviceMocker.registerMockService(mockKeyboard);
+
   MockClipboard mockClipboard = new MockClipboard();
-  serviceMocker.registerMockService(mockClipboard);
+  PlatformMessages.setMockJSONMessageHandler('flutter/platform', mockClipboard.handleJSONMessage);
 
   const String kThreeLines =
     'First line of text is here abcdef ghijkl mnopqrst. ' +