From 89b9519301451994c5b5f3a1cbe9962a3750cbc5 Mon Sep 17 00:00:00 2001
From: Tong Mu <dkwingsmt@gmail.com>
Date: Mon, 4 Nov 2019 18:58:17 -0800
Subject: [PATCH 01/14] Untested macOS impl

---
 shell/platform/darwin/macos/BUILD.gn          |   2 +
 .../Source/FlutterMouseCursorPlugin.h         |  26 +++
 .../Source/FlutterMouseCursorPlugin.mm        | 220 ++++++++++++++++++
 .../framework/Source/FlutterViewController.mm |   6 +
 4 files changed, 254 insertions(+)
 create mode 100644 shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.h
 create mode 100644 shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm

diff --git a/shell/platform/darwin/macos/BUILD.gn b/shell/platform/darwin/macos/BUILD.gn
index ff598fb8071c5..aef1cd7a6cd32 100644
--- a/shell/platform/darwin/macos/BUILD.gn
+++ b/shell/platform/darwin/macos/BUILD.gn
@@ -54,6 +54,8 @@ source_set("flutter_framework_source") {
     "framework/Source/FlutterEngine_Internal.h",
     "framework/Source/FlutterExternalTextureGL.h",
     "framework/Source/FlutterExternalTextureGL.mm",
+    "framework/Source/FlutterMouseCursorPlugin.h",
+    "framework/Source/FlutterMouseCursorPlugin.mm",
     "framework/Source/FlutterTextInputModel.h",
     "framework/Source/FlutterTextInputModel.mm",
     "framework/Source/FlutterTextInputPlugin.h",
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.h b/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.h
new file mode 100644
index 0000000000000..80512651f14b8
--- /dev/null
+++ b/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.h
@@ -0,0 +1,26 @@
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#import <Cocoa/Cocoa.h>
+
+#import "flutter/shell/platform/darwin/common/framework/Headers/FlutterBinaryMessenger.h"
+#import "flutter/shell/platform/darwin/macos/framework/Headers/FlutterViewController.h"
+
+/**
+ * A plugin to handle mouse cursor.
+ *
+ * Responsible for bridging the native macOS mouse cursor system with the
+ * Flutter framework mouse cursor classes, via system channels.
+ *
+ * This is not an FlutterPlugin since it needs access to FlutterViewController
+ * internals, so needs to be managed differently.
+ */
+@interface FlutterMouseCursorPlugin : NSObject
+
+/**
+ * Initializes a mouse cursor plugin that coordinates key event handling with
+ * |viewController|.
+ */
+- (nonnull instancetype)initWithViewController:(FlutterViewController*)viewController;
+
+@end
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm b/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm
new file mode 100644
index 0000000000000..4d4b67b24c979
--- /dev/null
+++ b/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm
@@ -0,0 +1,220 @@
+// Copyright 2019 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#import "flutter/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.h"
+
+#import <objc/message.h>
+
+#import "flutter/shell/platform/darwin/common/framework/Headers/FlutterCodecs.h"
+#import "flutter/shell/platform/darwin/macos/framework/Source/FlutterViewController_Internal.h"
+
+// System shape are constant integers used by the framework to represent a shape
+// of system cursors.
+//
+// They are intentionally designed to be meaningless integers.
+//
+// They must be kept in sync with Flutter framework's mouse_cursor.dart
+static int const kSystemShapeNone = 0x334c4a4c;
+static int const kSystemShapeBasic = 0xf17aaabc;
+static int const kSystemShapeClick = 0xa8affc08;
+static int const kSystemShapeText = 0x1cb251ec;
+static int const kSystemShapeForbidden = 0x7fa3b767;
+static int const kSystemShapeGrab = 0x28b91f80;
+static int const kSystemShapeGrabbing = 0x6631ce3e;
+
+static int const kDefaultSystemShape = kSystemShapeBasic;
+
+static NSString* const kMouseCursorChannel = @"flutter/mousecursor";
+
+static NSString* const kActivateShapeMethod = @"activateShape";
+static NSString* const kShapeKey = @"shape";
+static NSString* const kDeviceKey = @"device";
+
+@interface FlutterMouseCursorDeviceState : NSObject
+
+- (nonnull instancetype)initWithDevice:(int)device
+                                 shape:(nonnull NSCursor*)shape;
+
+- (void)dispose;
+
+- (BOOL)activateShape: (nonnull NSCursor *)shape;
+
+@property(readonly) int device;
+
+@property() NSCursor *shape;
+
+@end
+
+@implementation FlutterMouseCursorDeviceState {
+  BOOL _hidden;
+}
+
+- (nonnull instancetype)initWithDevice:(int)_device
+                                 shape:(nonnull NSCursor*)_shape {
+  device = _device;
+  shape = _shape;
+  _hidden = NO;
+  [shape set];
+  return self;
+}
+
+- (void)dispose {
+  if (_hidden)
+    [NSCursor unhide];
+}
+
+- (void)activateShape: (NSCursor *)targetShape {
+  if (targetShape == shape)
+    return;
+  [cursor set];
+  if (_hidden)
+    [NSCursor unhide];
+  shape = targetShape;
+  _hidden = NO;
+}
+
+- (void)hide {
+  if (!_hidden)
+    [NSCursor hide];
+}
+
+#pragma mark - Private
+
+@end
+
+@interface FlutterMouseCursorPlugin
+/**
+ * The channel used to communicate with Flutter.
+ */
+@property() FlutterMethodChannel* _channel;
+
+/**
+ * The FlutterViewController to manage input for.
+ */
+@property(nonatomic, weak) FlutterViewController* _flutterViewController;
+
+@property() NSDictionary *_shapeObjects;
+
+@property() FlutterMouseCursorDeviceState *_deviceState;
+
+@end
+
+@implementation FlutterMouseCursorPlugin
+
+- (instancetype)initWithViewController:(FlutterViewController*)viewController {
+  self = [super init];
+  if (self != nil) {
+    _flutterViewController = viewController;
+    _channel = [FlutterMethodChannel methodChannelWithName:kMouseCursorChannel
+                                           binaryMessenger:viewController.engine.binaryMessenger
+                                                     codec:[FlutterStandardMethodCodec sharedInstance]];
+    __weak FlutterMouseCursorPlugin* weakSelf = self;
+    [_channel setMethodCallHandler:^(FlutterMethodCall* call, FlutterResult result) {
+      [weakSelf handleMethodCall:call result:result];
+    }];
+    _shapeObjects = @{};
+  }
+  return self;
+}
+
+#pragma mark - Private
+
+- (void)handleMethodCall:(FlutterMethodCall*)call result:(FlutterResult)result {
+  BOOL handled = YES;
+  NSString* method = call.method;
+  if ([method isEqualToString:kActivateShapeMethod]) {
+    result([self activateShape:call.arguments]);
+  } else {
+    handled = NO;
+    NSLog(@"Unhandled mouse cursor method '%@'", method);
+    result(FlutterMethodNotImplemented);
+  }
+}
+
+- (id)activateShape:(NSDictionary*)arguments {
+  if (!arguments) {
+    return [FlutterError
+        errorWithCode:@"error"
+              message:@"Missing arguments"
+              details:@"Missing arguments while trying to activate shape"];
+  }
+  NSNumber* shapeArg = arguments[kShapeKey];
+  if (!shapeArg) {
+    return [FlutterError
+        errorWithCode:@"error"
+              message:@"Missing argument"
+              details:@"Missing argument shape while trying to activate shape"];
+  }
+  NSNumber* deviceArg = arguments[kDeviceKey];
+  if (!deviceArg) {
+    return [FlutterError
+        errorWithCode:@"error"
+              message:@"Missing argument"
+              details:@"Missing argument device while trying to activate shape"];
+  }
+  int shape = [shapeArg intValue];
+  int noNoneShape = shape == kSystemShapeNone ? kSystemShapeBasic : shape;
+  NSCursor* shapeObject = [self resolveShape: noNoneShape];
+  if (shapeObject == nil) {
+    // Unregistered shape. Return false to request fallback.
+    return [false];
+  }
+  [self ensureDevice: [deviceArg intValue] withShapeObject: shapeObject];
+  if (shape == kSystemShapeNone) {
+    [_deviceState hide];
+  } else {
+    [_deviceState activateShape: shapeObject];
+  }
+  return [true];
+}
+
+- (nullable NSCursor*)resolveShape:(int)shape {
+  NSCursor *cachedObject = _shapeObjects[shape];
+  if (cachedObject)
+    return cachedObject;
+  NSCursor *systemObject = [FlutterMouseCursorPlugin resolveSystemShape: shape];
+  if (!systemObject)
+    return nil;
+  _shapeObjects[shape] = systemObject;
+  return systemObject;
+}
+
+- (void)ensureDevice:(int)device
+     withShapeObject:(nonnull NSCursor*)shapeObject {
+  // MacOS only supports one device. Destroy the old when the new one is different.
+  if (_deviceState.device != device) {
+    [_deviceState dispose];
+    _deviceState = nil;
+  }
+  if (!_deviceState) {
+    _deviceState = [[FlutterMouseCursorDeviceState alloc] initWithDevice: device
+                                                                   shape: shapeObject];
+  }
+}
+
+#pragma mark - Static
+
+// Does not handle kSystemShapeNone.
+// Returns null for default.
++ (nullable NSCursor*)resolveSystemShape:(int)platformConstant {
+  switch (platformConstant) {
+    case kSystemShapeBasic:
+      return [NSCursor arrowCursor];
+    case kSystemShapeClick:
+      return [NSCursor pointingHandCursor];
+    case kSystemShapeText:
+      return [NSCursor IBeamCursor];
+    case kSystemShapeForbidden:
+      return [NSCursor operationNotAllowedCursor];
+    case kSystemShapeGrab:
+      return [NSCursor openHandCursor];
+    case kSystemShapeGrabbing:
+      return [NSCursor closedHandCursor];
+    default:
+      break;
+  }
+  return nil;
+}
+
+@end
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterViewController.mm b/shell/platform/darwin/macos/framework/Source/FlutterViewController.mm
index 2ea2070a1f737..870f7c79edad0 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterViewController.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterViewController.mm
@@ -8,6 +8,7 @@
 #import "flutter/shell/platform/darwin/common/framework/Headers/FlutterChannels.h"
 #import "flutter/shell/platform/darwin/common/framework/Headers/FlutterCodecs.h"
 #import "flutter/shell/platform/darwin/macos/framework/Headers/FlutterEngine.h"
+#import "flutter/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.h"
 #import "flutter/shell/platform/darwin/macos/framework/Source/FlutterEngine_Internal.h"
 #import "flutter/shell/platform/darwin/macos/framework/Source/FlutterTextInputPlugin.h"
 #import "flutter/shell/platform/darwin/macos/framework/Source/FlutterView.h"
@@ -168,6 +169,10 @@ @implementation FlutterViewController {
   // The project to run in this controller's engine.
   FlutterDartProject* _project;
 
+  // The plugin used to handle mouse cursor. This is not an FlutterPlugin, so must be owned
+  // separately.
+  FlutterMouseCursorPlugin* _mouseCursorPlugin;
+
   // The plugin used to handle text input. This is not an FlutterPlugin, so must be owned
   // separately.
   FlutterTextInputPlugin* _textInputPlugin;
@@ -317,6 +322,7 @@ - (void)configureTrackingArea {
 }
 
 - (void)addInternalPlugins {
+  _mouseCursorPlugin = [[FlutterMouseCursorPlugin alloc] initWithViewController:self];
   _textInputPlugin = [[FlutterTextInputPlugin alloc] initWithViewController:self];
   _keyEventChannel =
       [FlutterBasicMessageChannel messageChannelWithName:@"flutter/keyevent"

From 35521522ea1570f2c141b508f4ca4bf088e3a161 Mon Sep 17 00:00:00 2001
From: Tong Mu <dkwingsmt@gmail.com>
Date: Tue, 5 Nov 2019 11:23:56 -0800
Subject: [PATCH 02/14] Workable mac

---
 .../Source/FlutterMouseCursorPlugin.h         |  2 +-
 .../Source/FlutterMouseCursorPlugin.mm        | 80 ++++++++++---------
 2 files changed, 42 insertions(+), 40 deletions(-)

diff --git a/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.h b/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.h
index 80512651f14b8..c211a23c3a017 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.h
+++ b/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.h
@@ -21,6 +21,6 @@
  * Initializes a mouse cursor plugin that coordinates key event handling with
  * |viewController|.
  */
-- (nonnull instancetype)initWithViewController:(FlutterViewController*)viewController;
+- (nonnull instancetype)initWithViewController:(nonnull FlutterViewController*)viewController;
 
 @end
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm b/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm
index 4d4b67b24c979..c13532d9a0ee4 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm
@@ -23,8 +23,6 @@
 static int const kSystemShapeGrab = 0x28b91f80;
 static int const kSystemShapeGrabbing = 0x6631ce3e;
 
-static int const kDefaultSystemShape = kSystemShapeBasic;
-
 static NSString* const kMouseCursorChannel = @"flutter/mousecursor";
 
 static NSString* const kActivateShapeMethod = @"activateShape";
@@ -38,7 +36,7 @@ - (nonnull instancetype)initWithDevice:(int)device
 
 - (void)dispose;
 
-- (BOOL)activateShape: (nonnull NSCursor *)shape;
+- (void)activateShape: (nonnull NSCursor *)targetShape;
 
 @property(readonly) int device;
 
@@ -50,12 +48,12 @@ @implementation FlutterMouseCursorDeviceState {
   BOOL _hidden;
 }
 
-- (nonnull instancetype)initWithDevice:(int)_device
-                                 shape:(nonnull NSCursor*)_shape {
-  device = _device;
-  shape = _shape;
+- (nonnull instancetype)initWithDevice:(int)device
+                                 shape:(nonnull NSCursor*)shape {
+  _device = device;
+  _shape = shape;
   _hidden = NO;
-  [shape set];
+  [_shape set];
   return self;
 }
 
@@ -64,45 +62,48 @@ - (void)dispose {
     [NSCursor unhide];
 }
 
-- (void)activateShape: (NSCursor *)targetShape {
-  if (targetShape == shape)
+- (void)activateShape: (nonnull NSCursor *)targetShape {
+  if (targetShape == _shape && !_hidden)
     return;
-  [cursor set];
-  if (_hidden)
+  [targetShape set];
+  if (_hidden) {
     [NSCursor unhide];
-  shape = targetShape;
+  }
+  _shape = targetShape;
   _hidden = NO;
 }
 
 - (void)hide {
-  if (!_hidden)
+  if (!_hidden) {
     [NSCursor hide];
+  }
+  _hidden = YES;
 }
 
 #pragma mark - Private
 
 @end
 
-@interface FlutterMouseCursorPlugin
+@interface FlutterMouseCursorPlugin ()
 /**
  * The channel used to communicate with Flutter.
  */
-@property() FlutterMethodChannel* _channel;
+@property() FlutterMethodChannel* channel;
 
 /**
  * The FlutterViewController to manage input for.
  */
-@property(nonatomic, weak) FlutterViewController* _flutterViewController;
+@property(nonatomic, weak) FlutterViewController* flutterViewController;
 
-@property() NSDictionary *_shapeObjects;
+@property() NSMutableDictionary *shapeObjects;
 
-@property() FlutterMouseCursorDeviceState *_deviceState;
+@property() FlutterMouseCursorDeviceState *deviceState;
 
 @end
 
 @implementation FlutterMouseCursorPlugin
 
-- (instancetype)initWithViewController:(FlutterViewController*)viewController {
+- (instancetype)initWithViewController:(nonnull FlutterViewController*)viewController {
   self = [super init];
   if (self != nil) {
     _flutterViewController = viewController;
@@ -113,14 +114,14 @@ - (instancetype)initWithViewController:(FlutterViewController*)viewController {
     [_channel setMethodCallHandler:^(FlutterMethodCall* call, FlutterResult result) {
       [weakSelf handleMethodCall:call result:result];
     }];
-    _shapeObjects = @{};
+    _shapeObjects = [[NSMutableDictionary alloc] init];
   }
   return self;
 }
 
 #pragma mark - Private
 
-- (void)handleMethodCall:(FlutterMethodCall*)call result:(FlutterResult)result {
+- (void)handleMethodCall:(nonnull FlutterMethodCall*)call result:(FlutterResult)result {
   BOOL handled = YES;
   NSString* method = call.method;
   if ([method isEqualToString:kActivateShapeMethod]) {
@@ -132,7 +133,7 @@ - (void)handleMethodCall:(FlutterMethodCall*)call result:(FlutterResult)result {
   }
 }
 
-- (id)activateShape:(NSDictionary*)arguments {
+- (id)activateShape:(nonnull NSDictionary*)arguments {
   if (!arguments) {
     return [FlutterError
         errorWithCode:@"error"
@@ -153,43 +154,44 @@ - (id)activateShape:(NSDictionary*)arguments {
               message:@"Missing argument"
               details:@"Missing argument device while trying to activate shape"];
   }
-  int shape = [shapeArg intValue];
-  int noNoneShape = shape == kSystemShapeNone ? kSystemShapeBasic : shape;
-  NSCursor* shapeObject = [self resolveShape: noNoneShape];
+  NSNumber *noNoneShape = [shapeArg intValue] == kSystemShapeNone ?
+    [NSNumber numberWithInt:kSystemShapeBasic] :
+    shapeArg;
+  NSCursor* shapeObject = [self resolveShape:noNoneShape];
   if (shapeObject == nil) {
     // Unregistered shape. Return false to request fallback.
-    return [false];
+    return @(NO);
   }
-  [self ensureDevice: [deviceArg intValue] withShapeObject: shapeObject];
-  if (shape == kSystemShapeNone) {
+  [self ensureDevice:deviceArg withShapeObject:shapeObject];
+  if ([shapeArg intValue] == kSystemShapeNone) {
     [_deviceState hide];
   } else {
-    [_deviceState activateShape: shapeObject];
+    [_deviceState activateShape:shapeObject];
   }
-  return [true];
+  return @(YES);
 }
 
-- (nullable NSCursor*)resolveShape:(int)shape {
+- (nullable NSCursor*)resolveShape:(NSNumber*)shape {
   NSCursor *cachedObject = _shapeObjects[shape];
   if (cachedObject)
     return cachedObject;
-  NSCursor *systemObject = [FlutterMouseCursorPlugin resolveSystemShape: shape];
+  NSCursor *systemObject = [FlutterMouseCursorPlugin resolveSystemShape:shape];
   if (!systemObject)
     return nil;
   _shapeObjects[shape] = systemObject;
   return systemObject;
 }
 
-- (void)ensureDevice:(int)device
+- (void)ensureDevice:(NSNumber*)device
      withShapeObject:(nonnull NSCursor*)shapeObject {
   // MacOS only supports one device. Destroy the old when the new one is different.
-  if (_deviceState.device != device) {
+  if (_deviceState.device != [device intValue]) {
     [_deviceState dispose];
     _deviceState = nil;
   }
   if (!_deviceState) {
-    _deviceState = [[FlutterMouseCursorDeviceState alloc] initWithDevice: device
-                                                                   shape: shapeObject];
+    _deviceState = [[FlutterMouseCursorDeviceState alloc] initWithDevice:[device intValue]
+                                                                   shape:shapeObject];
   }
 }
 
@@ -197,8 +199,8 @@ - (void)ensureDevice:(int)device
 
 // Does not handle kSystemShapeNone.
 // Returns null for default.
-+ (nullable NSCursor*)resolveSystemShape:(int)platformConstant {
-  switch (platformConstant) {
++ (nullable NSCursor*)resolveSystemShape:(NSNumber*)platformConstant {
+  switch ([platformConstant intValue]) {
     case kSystemShapeBasic:
       return [NSCursor arrowCursor];
     case kSystemShapeClick:

From 38aedbb262d3f8197913be313234f59902ef7c1a Mon Sep 17 00:00:00 2001
From: Tong Mu <dkwingsmt@gmail.com>
Date: Mon, 4 May 2020 14:41:56 -0700
Subject: [PATCH 03/14] Modernize

---
 .../Source/FlutterMouseCursorPlugin.mm        | 44 +++++++++----------
 1 file changed, 22 insertions(+), 22 deletions(-)

diff --git a/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm b/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm
index c13532d9a0ee4..0d192805aabed 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm
@@ -15,18 +15,18 @@
 // They are intentionally designed to be meaningless integers.
 //
 // They must be kept in sync with Flutter framework's mouse_cursor.dart
-static int const kSystemShapeNone = 0x334c4a4c;
-static int const kSystemShapeBasic = 0xf17aaabc;
-static int const kSystemShapeClick = 0xa8affc08;
-static int const kSystemShapeText = 0x1cb251ec;
-static int const kSystemShapeForbidden = 0x7fa3b767;
-static int const kSystemShapeGrab = 0x28b91f80;
-static int const kSystemShapeGrabbing = 0x6631ce3e;
+static int const kSystemShapeNone = 0x334c4a;
+static int const kSystemShapeBasic = 0xf17aaa;
+static int const kSystemShapeClick = 0xa8affc;
+static int const kSystemShapeText = 0x1cb251;
+static int const kSystemShapeForbidden = 0x350f9d;
+static int const kSystemShapeGrab = 0x28b91f;
+static int const kSystemShapeGrabbing = 0x6631ce;
 
 static NSString* const kMouseCursorChannel = @"flutter/mousecursor";
 
-static NSString* const kActivateShapeMethod = @"activateShape";
-static NSString* const kShapeKey = @"shape";
+static NSString* const kActivateSystemCursorMethod = @"activateSystemCursor";
+static NSString* const kShapeCodeKey = @"shapeCode";
 static NSString* const kDeviceKey = @"device";
 
 @interface FlutterMouseCursorDeviceState : NSObject
@@ -124,8 +124,8 @@ - (instancetype)initWithViewController:(nonnull FlutterViewController*)viewContr
 - (void)handleMethodCall:(nonnull FlutterMethodCall*)call result:(FlutterResult)result {
   BOOL handled = YES;
   NSString* method = call.method;
-  if ([method isEqualToString:kActivateShapeMethod]) {
-    result([self activateShape:call.arguments]);
+  if ([method isEqualToString:kActivateSystemCursorMethod]) {
+    result([self activateSystemCursor:call.arguments]);
   } else {
     handled = NO;
     NSLog(@"Unhandled mouse cursor method '%@'", method);
@@ -133,37 +133,37 @@ - (void)handleMethodCall:(nonnull FlutterMethodCall*)call result:(FlutterResult)
   }
 }
 
-- (id)activateShape:(nonnull NSDictionary*)arguments {
+- (id)activateSystemCursor:(nonnull NSDictionary*)arguments {
   if (!arguments) {
     return [FlutterError
         errorWithCode:@"error"
               message:@"Missing arguments"
-              details:@"Missing arguments while trying to activate shape"];
+              details:@"Missing arguments while trying to activate system cursor"];
   }
-  NSNumber* shapeArg = arguments[kShapeKey];
-  if (!shapeArg) {
+  NSNumber* shapeCodeArg = arguments[kShapeCodeKey];
+  if (!shapeCodeArg) {
     return [FlutterError
         errorWithCode:@"error"
               message:@"Missing argument"
-              details:@"Missing argument shape while trying to activate shape"];
+              details:@"Missing argument shapeCode while trying to activate system cursor"];
   }
   NSNumber* deviceArg = arguments[kDeviceKey];
   if (!deviceArg) {
     return [FlutterError
         errorWithCode:@"error"
               message:@"Missing argument"
-              details:@"Missing argument device while trying to activate shape"];
+              details:@"Missing argument device while trying to activate system cursor"];
   }
-  NSNumber *noNoneShape = [shapeArg intValue] == kSystemShapeNone ?
+  NSNumber *noNoneShape = [shapeCodeArg intValue] == kSystemShapeNone ?
     [NSNumber numberWithInt:kSystemShapeBasic] :
-    shapeArg;
-  NSCursor* shapeObject = [self resolveShape:noNoneShape];
+    shapeCodeArg;
+  NSCursor* shapeObject = [self resolveShapeCode:noNoneShape];
   if (shapeObject == nil) {
     // Unregistered shape. Return false to request fallback.
     return @(NO);
   }
   [self ensureDevice:deviceArg withShapeObject:shapeObject];
-  if ([shapeArg intValue] == kSystemShapeNone) {
+  if ([shapeCodeArg intValue] == kSystemShapeNone) {
     [_deviceState hide];
   } else {
     [_deviceState activateShape:shapeObject];
@@ -171,7 +171,7 @@ - (id)activateShape:(nonnull NSDictionary*)arguments {
   return @(YES);
 }
 
-- (nullable NSCursor*)resolveShape:(NSNumber*)shape {
+- (nullable NSCursor*)resolveShapeCode:(NSNumber*)shape {
   NSCursor *cachedObject = _shapeObjects[shape];
   if (cachedObject)
     return cachedObject;

From 6272fc1e14b39599bb9be1034737455126d5b142 Mon Sep 17 00:00:00 2001
From: Tong Mu <dkwingsmt@gmail.com>
Date: Mon, 4 May 2020 15:09:41 -0700
Subject: [PATCH 04/14] Simplify

---
 .../Source/FlutterMouseCursorPlugin.mm        | 99 +++++--------------
 1 file changed, 24 insertions(+), 75 deletions(-)

diff --git a/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm b/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm
index 0d192805aabed..e3929d39e0719 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm
@@ -29,60 +29,6 @@
 static NSString* const kShapeCodeKey = @"shapeCode";
 static NSString* const kDeviceKey = @"device";
 
-@interface FlutterMouseCursorDeviceState : NSObject
-
-- (nonnull instancetype)initWithDevice:(int)device
-                                 shape:(nonnull NSCursor*)shape;
-
-- (void)dispose;
-
-- (void)activateShape: (nonnull NSCursor *)targetShape;
-
-@property(readonly) int device;
-
-@property() NSCursor *shape;
-
-@end
-
-@implementation FlutterMouseCursorDeviceState {
-  BOOL _hidden;
-}
-
-- (nonnull instancetype)initWithDevice:(int)device
-                                 shape:(nonnull NSCursor*)shape {
-  _device = device;
-  _shape = shape;
-  _hidden = NO;
-  [_shape set];
-  return self;
-}
-
-- (void)dispose {
-  if (_hidden)
-    [NSCursor unhide];
-}
-
-- (void)activateShape: (nonnull NSCursor *)targetShape {
-  if (targetShape == _shape && !_hidden)
-    return;
-  [targetShape set];
-  if (_hidden) {
-    [NSCursor unhide];
-  }
-  _shape = targetShape;
-  _hidden = NO;
-}
-
-- (void)hide {
-  if (!_hidden) {
-    [NSCursor hide];
-  }
-  _hidden = YES;
-}
-
-#pragma mark - Private
-
-@end
 
 @interface FlutterMouseCursorPlugin ()
 /**
@@ -97,12 +43,14 @@ @interface FlutterMouseCursorPlugin ()
 
 @property() NSMutableDictionary *shapeObjects;
 
-@property() FlutterMouseCursorDeviceState *deviceState;
+@property() NSCursor *shape;
 
 @end
 
 @implementation FlutterMouseCursorPlugin
 
+BOOL _hidden;
+
 - (instancetype)initWithViewController:(nonnull FlutterViewController*)viewController {
   self = [super init];
   if (self != nil) {
@@ -154,21 +102,15 @@ - (id)activateSystemCursor:(nonnull NSDictionary*)arguments {
               message:@"Missing argument"
               details:@"Missing argument device while trying to activate system cursor"];
   }
-  NSNumber *noNoneShape = [shapeCodeArg intValue] == kSystemShapeNone ?
-    [NSNumber numberWithInt:kSystemShapeBasic] :
-    shapeCodeArg;
-  NSCursor* shapeObject = [self resolveShapeCode:noNoneShape];
+  if ([shapeCodeArg intValue] == kSystemShapeNone) {
+    return [self hide];
+  }
+  NSCursor* shapeObject = [self resolveShapeCode:shapeCodeArg];
   if (shapeObject == nil) {
     // Unregistered shape. Return false to request fallback.
     return @(NO);
   }
-  [self ensureDevice:deviceArg withShapeObject:shapeObject];
-  if ([shapeCodeArg intValue] == kSystemShapeNone) {
-    [_deviceState hide];
-  } else {
-    [_deviceState activateShape:shapeObject];
-  }
-  return @(YES);
+  return [self activateShapeObject:shapeObject];
 }
 
 - (nullable NSCursor*)resolveShapeCode:(NSNumber*)shape {
@@ -182,17 +124,24 @@ - (nullable NSCursor*)resolveShapeCode:(NSNumber*)shape {
   return systemObject;
 }
 
-- (void)ensureDevice:(NSNumber*)device
-     withShapeObject:(nonnull NSCursor*)shapeObject {
-  // MacOS only supports one device. Destroy the old when the new one is different.
-  if (_deviceState.device != [device intValue]) {
-    [_deviceState dispose];
-    _deviceState = nil;
+- (id)activateShapeObject: (nonnull NSCursor *)targetShape {
+  if (targetShape == _shape && !_hidden)
+    return @(YES);
+  [targetShape set];
+  if (_hidden) {
+    [NSCursor unhide];
   }
-  if (!_deviceState) {
-    _deviceState = [[FlutterMouseCursorDeviceState alloc] initWithDevice:[device intValue]
-                                                                   shape:shapeObject];
+  _shape = targetShape;
+  _hidden = NO;
+  return @(YES);
+}
+
+- (id)hide {
+  if (!_hidden) {
+    [NSCursor hide];
   }
+  _hidden = YES;
+  return @(YES);
 }
 
 #pragma mark - Static

From 8ca0900f29eab5b60a8e308826aae2650de48a85 Mon Sep 17 00:00:00 2001
From: Tong Mu <dkwingsmt@gmail.com>
Date: Thu, 7 May 2020 19:58:33 -0700
Subject: [PATCH 05/14] Address comments

---
 .../Source/FlutterMouseCursorPlugin.mm        | 74 +++++++++----------
 1 file changed, 33 insertions(+), 41 deletions(-)

diff --git a/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm b/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm
index e3929d39e0719..0e94af9740d1d 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm
@@ -7,7 +7,6 @@
 #import <objc/message.h>
 
 #import "flutter/shell/platform/darwin/common/framework/Headers/FlutterCodecs.h"
-#import "flutter/shell/platform/darwin/macos/framework/Source/FlutterViewController_Internal.h"
 
 // System shape are constant integers used by the framework to represent a shape
 // of system cursors.
@@ -15,13 +14,13 @@
 // They are intentionally designed to be meaningless integers.
 //
 // They must be kept in sync with Flutter framework's mouse_cursor.dart
-static int const kSystemShapeNone = 0x334c4a;
-static int const kSystemShapeBasic = 0xf17aaa;
-static int const kSystemShapeClick = 0xa8affc;
-static int const kSystemShapeText = 0x1cb251;
-static int const kSystemShapeForbidden = 0x350f9d;
-static int const kSystemShapeGrab = 0x28b91f;
-static int const kSystemShapeGrabbing = 0x6631ce;
+static const int kSystemShapeNone = 0x334c4a;
+static const int kSystemShapeBasic = 0xf17aaa;
+static const int kSystemShapeClick = 0xa8affc;
+static const int kSystemShapeText = 0x1cb251;
+static const int kSystemShapeForbidden = 0x350f9d;
+static const int kSystemShapeGrab = 0x28b91f;
+static const int kSystemShapeGrabbing = 0x6631ce;
 
 static NSString* const kMouseCursorChannel = @"flutter/mousecursor";
 
@@ -29,28 +28,48 @@
 static NSString* const kShapeCodeKey = @"shapeCode";
 static NSString* const kDeviceKey = @"device";
 
+// Maps a Flutter's constant to a platform's cursor object.
+//
+// Returns nil for unknown constants, including kSystemShapeNone.
+static NSCursor* resolveSystemShape(NSNumber* platformConstant) {
+  switch ([platformConstant intValue]) {
+    case kSystemShapeBasic:
+      return [NSCursor arrowCursor];
+    case kSystemShapeClick:
+      return [NSCursor pointingHandCursor];
+    case kSystemShapeText:
+      return [NSCursor IBeamCursor];
+    case kSystemShapeForbidden:
+      return [NSCursor operationNotAllowedCursor];
+    case kSystemShapeGrab:
+      return [NSCursor openHandCursor];
+    case kSystemShapeGrabbing:
+      return [NSCursor closedHandCursor];
+  }
+  return nil;
+}
 
 @interface FlutterMouseCursorPlugin ()
 /**
  * The channel used to communicate with Flutter.
  */
-@property() FlutterMethodChannel* channel;
+@property(nonatomic) FlutterMethodChannel* channel;
 
 /**
  * The FlutterViewController to manage input for.
  */
 @property(nonatomic, weak) FlutterViewController* flutterViewController;
 
-@property() NSMutableDictionary *shapeObjects;
+@property(nonatomic) NSMutableDictionary *shapeObjects;
 
-@property() NSCursor *shape;
+@property(nonatomic) NSCursor *shape;
+
+@property(nonatomic) BOOL hidden;
 
 @end
 
 @implementation FlutterMouseCursorPlugin
 
-BOOL _hidden;
-
 - (instancetype)initWithViewController:(nonnull FlutterViewController*)viewController {
   self = [super init];
   if (self != nil) {
@@ -70,13 +89,10 @@ - (instancetype)initWithViewController:(nonnull FlutterViewController*)viewContr
 #pragma mark - Private
 
 - (void)handleMethodCall:(nonnull FlutterMethodCall*)call result:(FlutterResult)result {
-  BOOL handled = YES;
   NSString* method = call.method;
   if ([method isEqualToString:kActivateSystemCursorMethod]) {
     result([self activateSystemCursor:call.arguments]);
   } else {
-    handled = NO;
-    NSLog(@"Unhandled mouse cursor method '%@'", method);
     result(FlutterMethodNotImplemented);
   }
 }
@@ -117,7 +133,7 @@ - (nullable NSCursor*)resolveShapeCode:(NSNumber*)shape {
   NSCursor *cachedObject = _shapeObjects[shape];
   if (cachedObject)
     return cachedObject;
-  NSCursor *systemObject = [FlutterMouseCursorPlugin resolveSystemShape:shape];
+  NSCursor *systemObject = resolveSystemShape(shape);
   if (!systemObject)
     return nil;
   _shapeObjects[shape] = systemObject;
@@ -144,28 +160,4 @@ - (id)hide {
   return @(YES);
 }
 
-#pragma mark - Static
-
-// Does not handle kSystemShapeNone.
-// Returns null for default.
-+ (nullable NSCursor*)resolveSystemShape:(NSNumber*)platformConstant {
-  switch ([platformConstant intValue]) {
-    case kSystemShapeBasic:
-      return [NSCursor arrowCursor];
-    case kSystemShapeClick:
-      return [NSCursor pointingHandCursor];
-    case kSystemShapeText:
-      return [NSCursor IBeamCursor];
-    case kSystemShapeForbidden:
-      return [NSCursor operationNotAllowedCursor];
-    case kSystemShapeGrab:
-      return [NSCursor openHandCursor];
-    case kSystemShapeGrabbing:
-      return [NSCursor closedHandCursor];
-    default:
-      break;
-  }
-  return nil;
-}
-
 @end

From 55a63a52d4e270da23d664d18e0ea09e9da5e8e7 Mon Sep 17 00:00:00 2001
From: Tong Mu <dkwingsmt@gmail.com>
Date: Fri, 8 May 2020 16:58:18 -0700
Subject: [PATCH 06/14] Refactor with FlutterPlugin

---
 .../Source/FlutterMouseCursorPlugin.h         |  11 +-
 .../Source/FlutterMouseCursorPlugin.mm        | 100 ++++++------------
 .../framework/Source/FlutterViewController.mm |   6 +-
 3 files changed, 37 insertions(+), 80 deletions(-)

diff --git a/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.h b/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.h
index c211a23c3a017..052c9845357b0 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.h
+++ b/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.h
@@ -11,16 +11,7 @@
  *
  * Responsible for bridging the native macOS mouse cursor system with the
  * Flutter framework mouse cursor classes, via system channels.
- *
- * This is not an FlutterPlugin since it needs access to FlutterViewController
- * internals, so needs to be managed differently.
- */
-@interface FlutterMouseCursorPlugin : NSObject
-
-/**
- * Initializes a mouse cursor plugin that coordinates key event handling with
- * |viewController|.
  */
-- (nonnull instancetype)initWithViewController:(nonnull FlutterViewController*)viewController;
+@interface FlutterMouseCursorPlugin : NSObject <FlutterPlugin>
 
 @end
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm b/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm
index 0e94af9740d1d..f38a0ec7c7c77 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm
@@ -2,10 +2,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#import "flutter/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.h"
-
 #import <objc/message.h>
 
+#import "FlutterMouseCursorPlugin.h"
 #import "flutter/shell/platform/darwin/common/framework/Headers/FlutterCodecs.h"
 
 // System shape are constant integers used by the framework to represent a shape
@@ -30,11 +29,11 @@
 
 // Maps a Flutter's constant to a platform's cursor object.
 //
-// Returns nil for unknown constants, including kSystemShapeNone.
+// Returns the arrow cursor for unknown constants, including kSystemShapeNone.
 static NSCursor* resolveSystemShape(NSNumber* platformConstant) {
   switch ([platformConstant intValue]) {
     case kSystemShapeBasic:
-      return [NSCursor arrowCursor];
+      break;
     case kSystemShapeClick:
       return [NSCursor pointingHandCursor];
     case kSystemShapeText:
@@ -46,7 +45,7 @@
     case kSystemShapeGrabbing:
       return [NSCursor closedHandCursor];
   }
-  return nil;
+  return [NSCursor arrowCursor];;
 }
 
 @interface FlutterMouseCursorPlugin ()
@@ -56,47 +55,24 @@ @interface FlutterMouseCursorPlugin ()
 @property(nonatomic) FlutterMethodChannel* channel;
 
 /**
- * The FlutterViewController to manage input for.
+ * Whether the cursor is currently hidden. 
  */
-@property(nonatomic, weak) FlutterViewController* flutterViewController;
-
-@property(nonatomic) NSMutableDictionary *shapeObjects;
-
-@property(nonatomic) NSCursor *shape;
-
 @property(nonatomic) BOOL hidden;
 
 @end
 
 @implementation FlutterMouseCursorPlugin
 
-- (instancetype)initWithViewController:(nonnull FlutterViewController*)viewController {
+- (instancetype)initWithChannel:(FlutterMethodChannel *)channel {
   self = [super init];
-  if (self != nil) {
-    _flutterViewController = viewController;
-    _channel = [FlutterMethodChannel methodChannelWithName:kMouseCursorChannel
-                                           binaryMessenger:viewController.engine.binaryMessenger
-                                                     codec:[FlutterStandardMethodCodec sharedInstance]];
-    __weak FlutterMouseCursorPlugin* weakSelf = self;
-    [_channel setMethodCallHandler:^(FlutterMethodCall* call, FlutterResult result) {
-      [weakSelf handleMethodCall:call result:result];
-    }];
-    _shapeObjects = [[NSMutableDictionary alloc] init];
+  if (self) {
+    _channel = channel;
   }
   return self;
 }
 
 #pragma mark - Private
 
-- (void)handleMethodCall:(nonnull FlutterMethodCall*)call result:(FlutterResult)result {
-  NSString* method = call.method;
-  if ([method isEqualToString:kActivateSystemCursorMethod]) {
-    result([self activateSystemCursor:call.arguments]);
-  } else {
-    result(FlutterMethodNotImplemented);
-  }
-}
-
 - (id)activateSystemCursor:(nonnull NSDictionary*)arguments {
   if (!arguments) {
     return [FlutterError
@@ -105,59 +81,53 @@ - (id)activateSystemCursor:(nonnull NSDictionary*)arguments {
               details:@"Missing arguments while trying to activate system cursor"];
   }
   NSNumber* shapeCodeArg = arguments[kShapeCodeKey];
-  if (!shapeCodeArg) {
-    return [FlutterError
-        errorWithCode:@"error"
-              message:@"Missing argument"
-              details:@"Missing argument shapeCode while trying to activate system cursor"];
-  }
   NSNumber* deviceArg = arguments[kDeviceKey];
-  if (!deviceArg) {
+  if (!shapeCodeArg || !deviceArg) {
     return [FlutterError
         errorWithCode:@"error"
               message:@"Missing argument"
-              details:@"Missing argument device while trying to activate system cursor"];
+              details:@"Missing argument while trying to activate system cursor"];
   }
   if ([shapeCodeArg intValue] == kSystemShapeNone) {
-    return [self hide];
-  }
-  NSCursor* shapeObject = [self resolveShapeCode:shapeCodeArg];
-  if (shapeObject == nil) {
-    // Unregistered shape. Return false to request fallback.
-    return @(NO);
-  }
-  return [self activateShapeObject:shapeObject];
-}
-
-- (nullable NSCursor*)resolveShapeCode:(NSNumber*)shape {
-  NSCursor *cachedObject = _shapeObjects[shape];
-  if (cachedObject)
-    return cachedObject;
-  NSCursor *systemObject = resolveSystemShape(shape);
-  if (!systemObject)
+    [self hide];
     return nil;
-  _shapeObjects[shape] = systemObject;
-  return systemObject;
+  }
+  NSCursor* shapeObject = resolveSystemShape(shapeCodeArg);
+  [self activateShapeObject:shapeObject];
+  return nil;
 }
 
-- (id)activateShapeObject: (nonnull NSCursor *)targetShape {
-  if (targetShape == _shape && !_hidden)
-    return @(YES);
+- (void)activateShapeObject: (nonnull NSCursor *)targetShape {
   [targetShape set];
   if (_hidden) {
     [NSCursor unhide];
   }
-  _shape = targetShape;
   _hidden = NO;
-  return @(YES);
 }
 
-- (id)hide {
+- (void)hide {
   if (!_hidden) {
     [NSCursor hide];
   }
   _hidden = YES;
-  return @(YES);
+}
+
+#pragma mark - FlutterPlugin implementation
+
++ (void)registerWithRegistrar:(id<FlutterPluginRegistrar>)registrar {
+  FlutterMethodChannel *channel = [FlutterMethodChannel methodChannelWithName:kMouseCursorChannel
+                                                              binaryMessenger:registrar.messenger];
+  FlutterMouseCursorPlugin *instance = [[FlutterMouseCursorPlugin alloc] initWithChannel:channel];
+  [registrar addMethodCallDelegate:instance channel:channel];
+}
+
+- (void)handleMethodCall:(FlutterMethodCall *)call result:(FlutterResult)result {
+  NSString* method = call.method;
+  if ([method isEqualToString:kActivateSystemCursorMethod]) {
+    result([self activateSystemCursor:call.arguments]);
+  } else {
+    result(FlutterMethodNotImplemented);
+  }
 }
 
 @end
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterViewController.mm b/shell/platform/darwin/macos/framework/Source/FlutterViewController.mm
index 18ad460cbf4a2..34bee32373a74 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterViewController.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterViewController.mm
@@ -174,10 +174,6 @@ @implementation FlutterViewController {
   // The project to run in this controller's engine.
   FlutterDartProject* _project;
 
-  // The plugin used to handle mouse cursor. This is not an FlutterPlugin, so must be owned
-  // separately.
-  FlutterMouseCursorPlugin* _mouseCursorPlugin;
-
   // The plugin used to handle text input. This is not an FlutterPlugin, so must be owned
   // separately.
   FlutterTextInputPlugin* _textInputPlugin;
@@ -355,7 +351,7 @@ - (void)configureTrackingArea {
 }
 
 - (void)addInternalPlugins {
-  _mouseCursorPlugin = [[FlutterMouseCursorPlugin alloc] initWithViewController:self];
+  [FlutterMouseCursorPlugin registerWithRegistrar:[self registrarForPlugin:@"mousecursor"]];
   _textInputPlugin = [[FlutterTextInputPlugin alloc] initWithViewController:self];
   _keyEventChannel =
       [FlutterBasicMessageChannel messageChannelWithName:@"flutter/keyevent"

From cd7abf118fc11f78df446648f9262da6b150b0f8 Mon Sep 17 00:00:00 2001
From: Tong Mu <dkwingsmt@gmail.com>
Date: Fri, 8 May 2020 19:37:45 -0700
Subject: [PATCH 07/14] Cached dict

---
 .../Source/FlutterMouseCursorPlugin.mm        | 74 ++++++++++---------
 1 file changed, 39 insertions(+), 35 deletions(-)

diff --git a/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm b/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm
index f38a0ec7c7c77..42d0664535c46 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm
@@ -7,45 +7,36 @@
 #import "FlutterMouseCursorPlugin.h"
 #import "flutter/shell/platform/darwin/common/framework/Headers/FlutterCodecs.h"
 
-// System shape are constant integers used by the framework to represent a shape
-// of system cursors.
-//
-// They are intentionally designed to be meaningless integers.
-//
-// They must be kept in sync with Flutter framework's mouse_cursor.dart
-static const int kSystemShapeNone = 0x334c4a;
-static const int kSystemShapeBasic = 0xf17aaa;
-static const int kSystemShapeClick = 0xa8affc;
-static const int kSystemShapeText = 0x1cb251;
-static const int kSystemShapeForbidden = 0x350f9d;
-static const int kSystemShapeGrab = 0x28b91f;
-static const int kSystemShapeGrabbing = 0x6631ce;
-
 static NSString* const kMouseCursorChannel = @"flutter/mousecursor";
 
 static NSString* const kActivateSystemCursorMethod = @"activateSystemCursor";
-static NSString* const kShapeCodeKey = @"shapeCode";
+static NSString* const kKindKey = @"kind";
 static NSString* const kDeviceKey = @"device";
 
+static NSString* const kKindValueNone = @"none";
+
+static NSMutableDictionary* cachedSystemCursors;
+
 // Maps a Flutter's constant to a platform's cursor object.
 //
 // Returns the arrow cursor for unknown constants, including kSystemShapeNone.
-static NSCursor* resolveSystemShape(NSNumber* platformConstant) {
-  switch ([platformConstant intValue]) {
-    case kSystemShapeBasic:
-      break;
-    case kSystemShapeClick:
-      return [NSCursor pointingHandCursor];
-    case kSystemShapeText:
-      return [NSCursor IBeamCursor];
-    case kSystemShapeForbidden:
-      return [NSCursor operationNotAllowedCursor];
-    case kSystemShapeGrab:
-      return [NSCursor openHandCursor];
-    case kSystemShapeGrabbing:
-      return [NSCursor closedHandCursor];
-  }
-  return [NSCursor arrowCursor];;
+static NSCursor* mapKindToCursor(NSString* kind) {
+  // The following mapping must be kept in sync with Flutter framework's
+  // mouse_cursor.dart
+  if ([kind isEqualToString:@"basic"])
+    return [NSCursor arrowCursor];
+  else if ([kind isEqualToString:@"click"])
+    return [NSCursor pointingHandCursor];
+  else if ([kind isEqualToString:@"text"])
+    return [NSCursor IBeamCursor];
+  else if ([kind isEqualToString:@"forbidden"])
+    return [NSCursor operationNotAllowedCursor];
+  else if ([kind isEqualToString:@"grab"])
+    return [NSCursor openHandCursor];
+  else if ([kind isEqualToString:@"grabbing"])
+    return [NSCursor closedHandCursor];
+  else
+    return [NSCursor arrowCursor];
 }
 
 @interface FlutterMouseCursorPlugin ()
@@ -80,19 +71,19 @@ - (id)activateSystemCursor:(nonnull NSDictionary*)arguments {
               message:@"Missing arguments"
               details:@"Missing arguments while trying to activate system cursor"];
   }
-  NSNumber* shapeCodeArg = arguments[kShapeCodeKey];
+  NSString* kindArg = arguments[kKindKey];
   NSNumber* deviceArg = arguments[kDeviceKey];
-  if (!shapeCodeArg || !deviceArg) {
+  if (!kindArg || !deviceArg) {
     return [FlutterError
         errorWithCode:@"error"
               message:@"Missing argument"
               details:@"Missing argument while trying to activate system cursor"];
   }
-  if ([shapeCodeArg intValue] == kSystemShapeNone) {
+  if ([kindArg isEqualToString:kKindValueNone]) {
     [self hide];
     return nil;
   }
-  NSCursor* shapeObject = resolveSystemShape(shapeCodeArg);
+  NSCursor* shapeObject = [FlutterMouseCursorPlugin resolveKindToCursor:kindArg];
   [self activateShapeObject:shapeObject];
   return nil;
 }
@@ -112,6 +103,19 @@ - (void)hide {
   _hidden = YES;
 }
 
++ (NSCursor*)resolveKindToCursor:(NSString*)kind {
+  if (cachedSystemCursors == nil) {
+    cachedSystemCursors = [NSMutableDictionary dictionary];
+  }
+  
+  NSCursor* cachedValue = [cachedSystemCursors objectForKey:kind];
+  if (cachedValue == nil) {
+    cachedValue = mapKindToCursor(kind);
+    [cachedSystemCursors setValue:cachedValue forKey:kind];
+  }
+  return cachedValue;
+}
+
 #pragma mark - FlutterPlugin implementation
 
 + (void)registerWithRegistrar:(id<FlutterPluginRegistrar>)registrar {

From ec138bc9c73d4ffde03606769be2d5453b7b43f9 Mon Sep 17 00:00:00 2001
From: Tong Mu <dkwingsmt@gmail.com>
Date: Tue, 19 May 2020 11:34:12 -0700
Subject: [PATCH 08/14] Update per comments

---
 .../Source/FlutterMouseCursorPlugin.mm        | 86 ++++++++++++-------
 1 file changed, 54 insertions(+), 32 deletions(-)

diff --git a/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm b/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm
index 42d0664535c46..5a4bb1378d6fa 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm
@@ -15,12 +15,12 @@
 
 static NSString* const kKindValueNone = @"none";
 
-static NSMutableDictionary* cachedSystemCursors;
-
-// Maps a Flutter's constant to a platform's cursor object.
-//
-// Returns the arrow cursor for unknown constants, including kSystemShapeNone.
-static NSCursor* mapKindToCursor(NSString* kind) {
+/**
+ * Maps a Flutter's constant to a platform's cursor object.
+ *
+ * Returns the arrow cursor for unknown constants, including kSystemShapeNone.
+ */
+static NSCursor* GetCursorForKind(NSString* kind) {
   // The following mapping must be kept in sync with Flutter framework's
   // mouse_cursor.dart
   if ([kind isEqualToString:@"basic"])
@@ -41,36 +41,62 @@
 
 @interface FlutterMouseCursorPlugin ()
 /**
- * The channel used to communicate with Flutter.
+ * Whether the cursor is currently hidden.
  */
-@property(nonatomic) FlutterMethodChannel* channel;
+@property(nonatomic) BOOL hidden;
 
 /**
- * Whether the cursor is currently hidden. 
+ * Handles the method call that activates a system cursor.
+ *
+ * Returns a FlutterError if the arguments can not be recognized. Otherwise
+ * returns nil.
  */
-@property(nonatomic) BOOL hidden;
+- (FlutterError*)activateSystemCursor:(nonnull NSDictionary*)arguments;
+
+/**
+ * Displays the specified cursor.
+ *
+ * This method unhides the cursor before displaying the cursor, and updates
+ * internal states.
+ */
+- (void)displayCursorObject: (nonnull NSCursor *)cursorObject;
+
+/**
+ * Hides the cursor.
+ *
+ * This method hides the cursor if the cursor is currently unhidden, and
+ * updates internal states.
+ */
+- (void)hide;
+
+/**
+ * Handle all method calls.
+ */
+- (void)handleMethodCall:(FlutterMethodCall *)call result:(FlutterResult)result;
 
 @end
 
 @implementation FlutterMouseCursorPlugin
 
-- (instancetype)initWithChannel:(FlutterMethodChannel *)channel {
+#pragma mark - Private
+
+NSMutableDictionary* cachedSystemCursors;
+
+- (instancetype)init {
   self = [super init];
   if (self) {
-    _channel = channel;
+    cachedSystemCursors = [NSMutableDictionary dictionary];
   }
   return self;
 }
 
-#pragma mark - Private
-
-- (id)activateSystemCursor:(nonnull NSDictionary*)arguments {
-  if (!arguments) {
-    return [FlutterError
-        errorWithCode:@"error"
-              message:@"Missing arguments"
-              details:@"Missing arguments while trying to activate system cursor"];
+- (void)dealloc {
+  if (_hidden) {
+    [NSCursor unhide];
   }
+}
+
+- (FlutterError*)activateSystemCursor:(nonnull NSDictionary*)arguments {
   NSString* kindArg = arguments[kKindKey];
   NSNumber* deviceArg = arguments[kDeviceKey];
   if (!kindArg || !deviceArg) {
@@ -83,13 +109,13 @@ - (id)activateSystemCursor:(nonnull NSDictionary*)arguments {
     [self hide];
     return nil;
   }
-  NSCursor* shapeObject = [FlutterMouseCursorPlugin resolveKindToCursor:kindArg];
-  [self activateShapeObject:shapeObject];
+  NSCursor* cursorObject = [FlutterMouseCursorPlugin cursorFromKind:kindArg];
+  [self displayCursorObject:cursorObject];
   return nil;
 }
 
-- (void)activateShapeObject: (nonnull NSCursor *)targetShape {
-  [targetShape set];
+- (void)displayCursorObject: (nonnull NSCursor *)cursorObject {
+  [cursorObject set];
   if (_hidden) {
     [NSCursor unhide];
   }
@@ -103,14 +129,10 @@ - (void)hide {
   _hidden = YES;
 }
 
-+ (NSCursor*)resolveKindToCursor:(NSString*)kind {
-  if (cachedSystemCursors == nil) {
-    cachedSystemCursors = [NSMutableDictionary dictionary];
-  }
-  
++ (NSCursor*)cursorFromKind:(NSString*)kind {
   NSCursor* cachedValue = [cachedSystemCursors objectForKey:kind];
-  if (cachedValue == nil) {
-    cachedValue = mapKindToCursor(kind);
+  if (!cachedValue) {
+    cachedValue = GetCursorForKind(kind);
     [cachedSystemCursors setValue:cachedValue forKey:kind];
   }
   return cachedValue;
@@ -121,7 +143,7 @@ + (NSCursor*)resolveKindToCursor:(NSString*)kind {
 + (void)registerWithRegistrar:(id<FlutterPluginRegistrar>)registrar {
   FlutterMethodChannel *channel = [FlutterMethodChannel methodChannelWithName:kMouseCursorChannel
                                                               binaryMessenger:registrar.messenger];
-  FlutterMouseCursorPlugin *instance = [[FlutterMouseCursorPlugin alloc] initWithChannel:channel];
+  FlutterMouseCursorPlugin *instance = [[FlutterMouseCursorPlugin alloc] init];
   [registrar addMethodCallDelegate:instance channel:channel];
 }
 

From bd95f8278c998d0c0c276e4dd7e8af8ea4e03ea1 Mon Sep 17 00:00:00 2001
From: Tong Mu <dkwingsmt@gmail.com>
Date: Tue, 19 May 2020 13:00:54 -0700
Subject: [PATCH 09/14] format

---
 .../Source/FlutterMouseCursorPlugin.mm        | 19 +++++++++----------
 1 file changed, 9 insertions(+), 10 deletions(-)

diff --git a/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm b/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm
index 5a4bb1378d6fa..07fffd87caea0 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm
@@ -59,7 +59,7 @@ - (FlutterError*)activateSystemCursor:(nonnull NSDictionary*)arguments;
  * This method unhides the cursor before displaying the cursor, and updates
  * internal states.
  */
-- (void)displayCursorObject: (nonnull NSCursor *)cursorObject;
+- (void)displayCursorObject:(nonnull NSCursor*)cursorObject;
 
 /**
  * Hides the cursor.
@@ -72,7 +72,7 @@ - (void)hide;
 /**
  * Handle all method calls.
  */
-- (void)handleMethodCall:(FlutterMethodCall *)call result:(FlutterResult)result;
+- (void)handleMethodCall:(FlutterMethodCall*)call result:(FlutterResult)result;
 
 @end
 
@@ -100,10 +100,9 @@ - (FlutterError*)activateSystemCursor:(nonnull NSDictionary*)arguments {
   NSString* kindArg = arguments[kKindKey];
   NSNumber* deviceArg = arguments[kDeviceKey];
   if (!kindArg || !deviceArg) {
-    return [FlutterError
-        errorWithCode:@"error"
-              message:@"Missing argument"
-              details:@"Missing argument while trying to activate system cursor"];
+    return [FlutterError errorWithCode:@"error"
+                               message:@"Missing argument"
+                               details:@"Missing argument while trying to activate system cursor"];
   }
   if ([kindArg isEqualToString:kKindValueNone]) {
     [self hide];
@@ -114,7 +113,7 @@ - (FlutterError*)activateSystemCursor:(nonnull NSDictionary*)arguments {
   return nil;
 }
 
-- (void)displayCursorObject: (nonnull NSCursor *)cursorObject {
+- (void)displayCursorObject:(nonnull NSCursor*)cursorObject {
   [cursorObject set];
   if (_hidden) {
     [NSCursor unhide];
@@ -141,13 +140,13 @@ + (NSCursor*)cursorFromKind:(NSString*)kind {
 #pragma mark - FlutterPlugin implementation
 
 + (void)registerWithRegistrar:(id<FlutterPluginRegistrar>)registrar {
-  FlutterMethodChannel *channel = [FlutterMethodChannel methodChannelWithName:kMouseCursorChannel
+  FlutterMethodChannel* channel = [FlutterMethodChannel methodChannelWithName:kMouseCursorChannel
                                                               binaryMessenger:registrar.messenger];
-  FlutterMouseCursorPlugin *instance = [[FlutterMouseCursorPlugin alloc] init];
+  FlutterMouseCursorPlugin* instance = [[FlutterMouseCursorPlugin alloc] init];
   [registrar addMethodCallDelegate:instance channel:channel];
 }
 
-- (void)handleMethodCall:(FlutterMethodCall *)call result:(FlutterResult)result {
+- (void)handleMethodCall:(FlutterMethodCall*)call result:(FlutterResult)result {
   NSString* method = call.method;
   if ([method isEqualToString:kActivateSystemCursorMethod]) {
     result([self activateSystemCursor:call.arguments]);

From 8da2c72155762882416ed5262dc0f94d24e16c44 Mon Sep 17 00:00:00 2001
From: Tong Mu <dkwingsmt@gmail.com>
Date: Tue, 19 May 2020 13:49:34 -0700
Subject: [PATCH 10/14] Remove device arg

---
 .../darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm b/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm
index 07fffd87caea0..f9d54c08bc7eb 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm
@@ -11,7 +11,6 @@
 
 static NSString* const kActivateSystemCursorMethod = @"activateSystemCursor";
 static NSString* const kKindKey = @"kind";
-static NSString* const kDeviceKey = @"device";
 
 static NSString* const kKindValueNone = @"none";
 
@@ -98,8 +97,7 @@ - (void)dealloc {
 
 - (FlutterError*)activateSystemCursor:(nonnull NSDictionary*)arguments {
   NSString* kindArg = arguments[kKindKey];
-  NSNumber* deviceArg = arguments[kDeviceKey];
-  if (!kindArg || !deviceArg) {
+  if (!kindArg) {
     return [FlutterError errorWithCode:@"error"
                                message:@"Missing argument"
                                details:@"Missing argument while trying to activate system cursor"];

From 17bd7d8016b61b7c9a6b07915aced1646b6dd2a4 Mon Sep 17 00:00:00 2001
From: Tong Mu <dkwingsmt@gmail.com>
Date: Tue, 19 May 2020 14:59:40 -0700
Subject: [PATCH 11/14] Format

---
 .../darwin/macos/framework/Source/FlutterViewController.mm      | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/shell/platform/darwin/macos/framework/Source/FlutterViewController.mm b/shell/platform/darwin/macos/framework/Source/FlutterViewController.mm
index 34bee32373a74..31708f233ce37 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterViewController.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterViewController.mm
@@ -8,8 +8,8 @@
 #import "flutter/shell/platform/darwin/common/framework/Headers/FlutterChannels.h"
 #import "flutter/shell/platform/darwin/common/framework/Headers/FlutterCodecs.h"
 #import "flutter/shell/platform/darwin/macos/framework/Headers/FlutterEngine.h"
-#import "flutter/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.h"
 #import "flutter/shell/platform/darwin/macos/framework/Source/FlutterEngine_Internal.h"
+#import "flutter/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.h"
 #import "flutter/shell/platform/darwin/macos/framework/Source/FlutterTextInputPlugin.h"
 #import "flutter/shell/platform/darwin/macos/framework/Source/FlutterView.h"
 #import "flutter/shell/platform/embedder/embedder.h"

From 81fd9dd4785f00c36f04e62ffaec3472dc9c9593 Mon Sep 17 00:00:00 2001
From: Tong Mu <dkwingsmt@gmail.com>
Date: Tue, 19 May 2020 16:34:16 -0700
Subject: [PATCH 12/14] Update license

---
 .../darwin/macos/framework/Source/FlutterMouseCursorPlugin.h     | 1 +
 1 file changed, 1 insertion(+)

diff --git a/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.h b/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.h
index 052c9845357b0..73b1d63e87d92 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.h
+++ b/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.h
@@ -1,3 +1,4 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 

From 033014f07e2755c0c1c01978609fee0656f58e12 Mon Sep 17 00:00:00 2001
From: Tong Mu <dkwingsmt@gmail.com>
Date: Tue, 19 May 2020 16:46:34 -0700
Subject: [PATCH 13/14] Update licences

---
 ci/licenses_golden/licenses_flutter                             | 2 ++
 .../darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm   | 2 +-
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/ci/licenses_golden/licenses_flutter b/ci/licenses_golden/licenses_flutter
index 4aad0ab44b3e8..77cb61b3f608d 100755
--- a/ci/licenses_golden/licenses_flutter
+++ b/ci/licenses_golden/licenses_flutter
@@ -956,6 +956,8 @@ FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterEngin
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterEngine_Internal.h
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterExternalTextureGL.h
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterExternalTextureGL.mm
+FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.h
+FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterTextInputModel.h
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterTextInputModel.mm
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterTextInputPlugin.h
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm b/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm
index f9d54c08bc7eb..931e354b1d592 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm
@@ -1,4 +1,4 @@
-// Copyright 2019 The Flutter Authors. All rights reserved.
+// Copyright 2013 The Flutter Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 

From 021d2c3cc3cbb81a4b65f75bdb4c9d371c75742f Mon Sep 17 00:00:00 2001
From: Tong Mu <dkwingsmt@gmail.com>
Date: Wed, 20 May 2020 13:26:18 -0700
Subject: [PATCH 14/14] Doc update

---
 .../macos/framework/Source/FlutterMouseCursorPlugin.mm     | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm b/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm
index 931e354b1d592..6bf19720c7194 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm
@@ -55,21 +55,18 @@ - (FlutterError*)activateSystemCursor:(nonnull NSDictionary*)arguments;
 /**
  * Displays the specified cursor.
  *
- * This method unhides the cursor before displaying the cursor, and updates
+ * Unhides the cursor before displaying the cursor, and updates
  * internal states.
  */
 - (void)displayCursorObject:(nonnull NSCursor*)cursorObject;
 
 /**
  * Hides the cursor.
- *
- * This method hides the cursor if the cursor is currently unhidden, and
- * updates internal states.
  */
 - (void)hide;
 
 /**
- * Handle all method calls.
+ * Handles all method calls from Flutter.
  */
 - (void)handleMethodCall:(FlutterMethodCall*)call result:(FlutterResult)result;