Refactor and migrate FlutterUndoManagerPlugin to ARC

shell/platform/darwin/ios/BUILD.gn

@@ -84,6 +84,9 @@ source_set("flutter_framework_source_arc") {
     "framework/Source/FlutterTextureRegistryRelay.mm",
     "framework/Source/FlutterUIPressProxy.h",
     "framework/Source/FlutterUIPressProxy.mm",
+    "framework/Source/FlutterUndoManagerDelegate.h",
+    "framework/Source/FlutterUndoManagerPlugin.h",
+    "framework/Source/FlutterUndoManagerPlugin.mm",
     "framework/Source/KeyCodeMap.g.mm",
     "framework/Source/KeyCodeMap_Internal.h",
     "framework/Source/UIViewController+FlutterScreenAndSceneIfLoaded.h",
@@ -157,9 +160,6 @@ source_set("flutter_framework_source") {
     "framework/Source/FlutterPluginAppLifeCycleDelegate.mm",
     "framework/Source/FlutterSemanticsScrollView.h",
     "framework/Source/FlutterSemanticsScrollView.mm",
-    "framework/Source/FlutterUndoManagerDelegate.h",
-    "framework/Source/FlutterUndoManagerPlugin.h",
-    "framework/Source/FlutterUndoManagerPlugin.mm",
     "framework/Source/FlutterView.h",
     "framework/Source/FlutterView.mm",
     "framework/Source/FlutterViewController.mm",

shell/platform/darwin/ios/framework/Source/FlutterEngine.mm

@@ -430,7 +430,6 @@ - (void)setViewController:(FlutterViewController*)viewController {
   [self maybeSetupPlatformViewChannels];
   [self updateDisplays];
   _textInputPlugin.get().viewController = viewController;
-  _undoManagerPlugin.get().viewController = viewController;
 
   if (viewController) {
     __block FlutterEngine* blockSelf = self;
@@ -465,7 +464,6 @@ - (void)setFlutterViewControllerWillDeallocObserver:(id<NSObject>)observer {
 - (void)notifyViewControllerDeallocated {
   [[self lifecycleChannel] sendMessage:@"AppLifecycleState.detached"];
   _textInputPlugin.get().viewController = nil;
-  _undoManagerPlugin.get().viewController = nil;
   if (!_allowHeadlessExecution) {
     [self destroyContext];
   } else if (_shell) {
@@ -1189,12 +1187,19 @@ - (void)flutterTextInputView:(FlutterTextInputView*)textInputView
 
 #pragma mark - Undo Manager Delegate
 
-- (void)flutterUndoManagerPlugin:(FlutterUndoManagerPlugin*)undoManagerPlugin
-         handleUndoWithDirection:(FlutterUndoRedoDirection)direction {
+- (void)handleUndoWithDirection:(FlutterUndoRedoDirection)direction {
   NSString* action = (direction == FlutterUndoRedoDirectionUndo) ? @"undo" : @"redo";
   [_undoManagerChannel.get() invokeMethod:@"UndoManagerClient.handleUndo" arguments:@[ action ]];
 }
 
+- (UIView<UITextInput>*)activeTextInputView {
+  return [[self textInputPlugin] textInputView];
+}
+
+- (NSUndoManager*)undoManager {
+  return self.viewController.undoManager;
+}
+
 #pragma mark - Screenshot Delegate
 
 - (flutter::Rasterizer::Screenshot)takeScreenshot:(flutter::Rasterizer::ScreenshotType)type

shell/platform/darwin/ios/framework/Source/FlutterUndoManagerDelegate.h

@@ -16,11 +16,29 @@ typedef NS_ENUM(NSInteger, FlutterUndoRedoDirection) {
   // NOLINTEND(readability-identifier-naming)
 };
 
-@class FlutterUndoManagerPlugin;
-
+/**
+ * Protocol for undo manager changes from the `FlutterUndoManagerPlugin`, typically a
+ * `FlutterEngine`.
+ */
 @protocol FlutterUndoManagerDelegate <NSObject>
-- (void)flutterUndoManagerPlugin:(FlutterUndoManagerPlugin*)undoManagerPlugin
-         handleUndoWithDirection:(FlutterUndoRedoDirection)direction;
+
+/**
+ * The `NSUndoManager` that should be managed by the `FlutterUndoManagerPlugin`.
+ * When the delegate is `FlutterEngine` this will be the `FlutterViewController`'s undo manager.
+ */
+@property(nonatomic, readonly, nullable) NSUndoManager* undoManager;
+
+/**
+ * Used to notify the active view when undo manager state (can redo/can undo)
+ * changes, in order to force keyboards to update undo/redo buttons.
+ */
+@property(nonatomic, readonly, nullable) UIView<UITextInput>* activeTextInputView;
+
+/**
+ * Pass changes to the framework through the undo manager channel.
+ */
+- (void)handleUndoWithDirection:(FlutterUndoRedoDirection)direction;
+
 @end
 NS_ASSUME_NONNULL_END
 

shell/platform/darwin/ios/framework/Source/FlutterUndoManagerPlugin.h

@@ -7,15 +7,11 @@
 
 #import <UIKit/UIKit.h>
 
-#import "flutter/fml/memory/weak_ptr.h"
 #import "flutter/shell/platform/darwin/common/framework/Headers/FlutterChannels.h"
-#import "flutter/shell/platform/darwin/ios/framework/Headers/FlutterViewController.h"
 #import "flutter/shell/platform/darwin/ios/framework/Source/FlutterUndoManagerDelegate.h"
 
 @interface FlutterUndoManagerPlugin : NSObject
 
-@property(nonatomic, assign) FlutterViewController* viewController;
-
 - (instancetype)init NS_UNAVAILABLE;
 + (instancetype)new NS_UNAVAILABLE;
 

shell/platform/darwin/ios/framework/Source/FlutterUndoManagerPlugin.mm

@@ -3,12 +3,6 @@
 // found in the LICENSE file.
 
 #import "flutter/shell/platform/darwin/ios/framework/Source/FlutterUndoManagerPlugin.h"
-#import "flutter/shell/platform/darwin/ios/framework/Source/FlutterEngine_Internal.h"
-
-#import <Foundation/Foundation.h>
-#import <UIKit/UIKit.h>
-
-#include "flutter/fml/logging.h"
 
 #pragma mark - UndoManager channel method names.
 static NSString* const kSetUndoStateMethod = @"UndoManager.setUndoState";
@@ -17,24 +11,24 @@
 static NSString* const kCanUndo = @"canUndo";
 static NSString* const kCanRedo = @"canRedo";
 
-@implementation FlutterUndoManagerPlugin {
-  id<FlutterUndoManagerDelegate> _undoManagerDelegate;
-}
+@interface FlutterUndoManagerPlugin ()
+@property(nonatomic, weak, readonly) id<FlutterUndoManagerDelegate> undoManagerDelegate;
+@end
+
+@implementation FlutterUndoManagerPlugin
 
 - (instancetype)initWithDelegate:(id<FlutterUndoManagerDelegate>)undoManagerDelegate {
   self = [super init];
 
   if (self) {
-    // `_undoManagerDelegate` is a weak reference because it should retain FlutterUndoManagerPlugin.
     _undoManagerDelegate = undoManagerDelegate;
   }
 
   return self;
 }
 
 - (void)dealloc {
-  [self resetUndoManager];
-  [super dealloc];
+  [_undoManagerDelegate.undoManager removeAllActionsWithTarget:self];
 }
 
 - (void)handleMethodCall:(FlutterMethodCall*)call result:(FlutterResult)result {
@@ -48,46 +42,43 @@ - (void)handleMethodCall:(FlutterMethodCall*)call result:(FlutterResult)result {
   }
 }
 
-- (NSUndoManager*)undoManager {
-  return _viewController.undoManager;
-}
-
-- (void)resetUndoManager API_AVAILABLE(ios(9.0)) {
-  [[self undoManager] removeAllActionsWithTarget:self];
+- (void)resetUndoManager {
+  [self.undoManagerDelegate.undoManager removeAllActionsWithTarget:self];
 }
 
-- (void)registerUndoWithDirection:(FlutterUndoRedoDirection)direction API_AVAILABLE(ios(9.0)) {
-  [[self undoManager] beginUndoGrouping];
-  [[self undoManager] registerUndoWithTarget:self
-                                     handler:^(id target) {
-                                       // Register undo with opposite direction.
-                                       FlutterUndoRedoDirection newDirection =
-                                           (direction == FlutterUndoRedoDirectionRedo)
-                                               ? FlutterUndoRedoDirectionUndo
-                                               : FlutterUndoRedoDirectionRedo;
-                                       [target registerUndoWithDirection:newDirection];
-                                       // Invoke method on delegate.
-                                       [_undoManagerDelegate flutterUndoManagerPlugin:self
-                                                              handleUndoWithDirection:direction];
-                                     }];
-  [[self undoManager] endUndoGrouping];
+- (void)registerUndoWithDirection:(FlutterUndoRedoDirection)direction {
+  NSUndoManager* undoManager = self.undoManagerDelegate.undoManager;
+  [undoManager beginUndoGrouping];
+  [undoManager registerUndoWithTarget:self
+                              handler:^(FlutterUndoManagerPlugin* target) {
+                                // Register undo with opposite direction.
+                                FlutterUndoRedoDirection newDirection =
+                                    (direction == FlutterUndoRedoDirectionRedo)
+                                        ? FlutterUndoRedoDirectionUndo
+                                        : FlutterUndoRedoDirectionRedo;
+                                [target registerUndoWithDirection:newDirection];
+                                // Invoke method on delegate.
+                                [target.undoManagerDelegate handleUndoWithDirection:direction];
+                              }];
+  [undoManager endUndoGrouping];
 }
 
-- (void)registerRedo API_AVAILABLE(ios(9.0)) {
-  [[self undoManager] beginUndoGrouping];
-  [[self undoManager]
-      registerUndoWithTarget:self
-                     handler:^(id target) {
-                       // Register undo with opposite direction.
-                       [target registerUndoWithDirection:FlutterUndoRedoDirectionRedo];
-                     }];
-  [[self undoManager] endUndoGrouping];
-  [[self undoManager] undo];
+- (void)registerRedo {
+  NSUndoManager* undoManager = self.undoManagerDelegate.undoManager;
+  [undoManager beginUndoGrouping];
+  [undoManager registerUndoWithTarget:self
+                              handler:^(id target) {
+                                // Register undo with opposite direction.
+                                [target registerUndoWithDirection:FlutterUndoRedoDirectionRedo];
+                              }];
+  [undoManager endUndoGrouping];
+  [undoManager undo];
 }
 
-- (void)setUndoState:(NSDictionary*)dictionary API_AVAILABLE(ios(9.0)) {
-  BOOL groupsByEvent = [self undoManager].groupsByEvent;
-  [self undoManager].groupsByEvent = NO;
+- (void)setUndoState:(NSDictionary*)dictionary {
+  NSUndoManager* undoManager = self.undoManagerDelegate.undoManager;
+  BOOL groupsByEvent = undoManager.groupsByEvent;
+  undoManager.groupsByEvent = NO;
   BOOL canUndo = [dictionary[kCanUndo] boolValue];
   BOOL canRedo = [dictionary[kCanRedo] boolValue];
 
@@ -99,16 +90,15 @@ - (void)setUndoState:(NSDictionary*)dictionary API_AVAILABLE(ios(9.0)) {
   if (canRedo) {
     [self registerRedo];
   }
-
-  if (_viewController.engine.textInputPlugin.textInputView != nil) {
+  UIView<UITextInput>* textInputView = self.undoManagerDelegate.activeTextInputView;
+  if (textInputView != nil) {
     // This is needed to notify the iPadOS keyboard that it needs to update the
     // state of the UIBarButtons. Otherwise, the state changes to NSUndoManager
     // will not show up until the next keystroke (or other trigger).
-    UITextInputAssistantItem* assistantItem =
-        _viewController.engine.textInputPlugin.textInputView.inputAssistantItem;
+    UITextInputAssistantItem* assistantItem = textInputView.inputAssistantItem;
     assistantItem.leadingBarButtonGroups = assistantItem.leadingBarButtonGroups;
   }
-  [self undoManager].groupsByEvent = groupsByEvent;
+  undoManager.groupsByEvent = groupsByEvent;
 }
 
 @end