[macOS] Handle termination in FlutterAppDelegate

ci/licenses_golden/licenses_flutter

@@ -2618,7 +2618,6 @@ ORIGIN: ../../../flutter/shell/platform/darwin/macos/framework/Source/Accessibil
 ORIGIN: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterAppDelegate.mm + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterAppDelegate_Internal.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterApplication.mm + ../../../flutter/LICENSE
-ORIGIN: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterApplication_Internal.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterBackingStore.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterBackingStore.mm + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterChannelKeyResponder.h + ../../../flutter/LICENSE
@@ -5214,7 +5213,6 @@ FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/Accessibilit
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterAppDelegate.mm
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterAppDelegate_Internal.h
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterApplication.mm
-FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterApplication_Internal.h
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterBackingStore.h
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterBackingStore.mm
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterChannelKeyResponder.h

shell/platform/darwin/macos/framework/Source/FlutterAppDelegate.mm

@@ -42,13 +42,6 @@ - (void)applicationWillFinishLaunching:(NSNotification*)notification {
   }
 }
 
-// This always returns NSTerminateNow, since by the time we get here, the
-// application has already been asked if it should terminate or not, and if not,
-// then termination never gets this far.
-- (NSApplicationTerminateReply)applicationShouldTerminate:(NSApplication*)sender {
-  return NSTerminateNow;
-}
-
 #pragma mark Private Methods
 
 - (NSString*)applicationName {
@@ -60,4 +53,22 @@ - (NSString*)applicationName {
   return applicationName;
 }
 
+- (NSApplicationTerminateReply)applicationShouldTerminate:(NSApplication* _Nonnull)sender {
+  // If the framework has already told us to terminate, terminate immediately.
+  if ([[self terminationHandler] shouldTerminate]) {
+    return NSTerminateNow;
+  }
+
+  // Send a termination request to the framework.
+  FlutterEngineTerminationHandler* terminationHandler = [self terminationHandler];
+  [terminationHandler requestApplicationTermination:sender
+                                           exitType:kFlutterAppExitTypeCancelable
+                                             result:nil];
+
+  // Cancel termination to allow the framework to handle the request asynchronously. When the
+  // termination request returns from the app, if termination is desired, this method will be
+  // reinvoked with self.terminationHandler.shouldTerminate set to YES.
+  return NSTerminateCancel;
+}
+
 @end

shell/platform/darwin/macos/framework/Source/FlutterApplication.mm

@@ -3,88 +3,6 @@
 // found in the LICENSE file.
 
 #import "flutter/shell/platform/darwin/macos/framework/Headers/FlutterApplication.h"
-#import "flutter/shell/platform/darwin/macos/framework/Source/FlutterApplication_Internal.h"
 
-#import "flutter/shell/platform/darwin/macos/framework/Headers/FlutterAppDelegate.h"
-#import "flutter/shell/platform/darwin/macos/framework/Source/FlutterAppDelegate_Internal.h"
-#import "flutter/shell/platform/darwin/macos/framework/Source/FlutterEngine_Internal.h"
-#include "flutter/shell/platform/embedder/embedder.h"
-
-// An NSApplication subclass that implements overrides necessary for some
-// Flutter features, like application lifecycle handling.
 @implementation FlutterApplication
-
-// Initialize NSApplication using the custom subclass. Check whether NSApp was
-// already initialized using another class, because that would break some
-// things. Warn about the mismatch only once, and only in debug builds.
-+ (NSApplication*)sharedApplication {
-  NSApplication* app = [super sharedApplication];
-
-  // +sharedApplication initializes the global NSApp, so if we're delivering
-  // something other than a FlutterApplication, warn the developer once.
-#ifndef FLUTTER_RELEASE
-  static dispatch_once_t onceToken = 0;
-  dispatch_once(&onceToken, ^{
-    if (![app respondsToSelector:@selector(terminateApplication:)]) {
-      NSLog(@"NSApp should be of type %s, not %s.\n"
-             "System requests for the application to terminate will not be sent to "
-             "the Flutter framework, so the framework will be unable to cancel "
-             "those requests.\n"
-             "Modify the application's NSPrincipleClass to be %s in the "
-             "Info.plist to fix this.",
-            [[self className] UTF8String], [[NSApp className] UTF8String],
-            [[self className] UTF8String]);
-    }
-  });
-#endif  // !FLUTTER_RELEASE
-  return app;
-}
-
-// |terminate| is the entry point for orderly "quit" operations in Cocoa. This
-// includes the application menu's Quit menu item and keyboard equivalent, the
-// application's dock icon menu's Quit menu item, "quit" (not "force quit") in
-// the Activity Monitor, and quits triggered by user logout and system restart
-// and shutdown.
-//
-// We override the normal |terminate| implementation. Our implementation, which
-// is specific to the asynchronous nature of Flutter, works by asking the
-// application delegate to terminate using its |requestApplicationTermination|
-// method instead of going through |applicationShouldTerminate|.
-//
-// The standard |applicationShouldTerminate| is not used because returning
-// NSTerminateLater from that function moves the run loop into a modal dialog
-// mode (NSModalPanelRunLoopMode), which stops the main run loop from processing
-// messages like, for instance, the response to the method channel call, and
-// code paths leading to it must be redirected to |requestApplicationTermination|.
-//
-// |requestApplicationTermination| differs from the standard
-// |applicationShouldTerminate| in that no special event loop is run in the case
-// that immediate termination is not possible (e.g., if dialog boxes allowing
-// the user to cancel have to be shown, or data needs to be saved). Instead,
-// requestApplicationTermination sends a method channel call to the framework asking
-// it if it is OK to terminate. When that method channel call returns with a
-// result, the application either terminates or continues running.
-- (void)terminate:(id)sender {
-  FlutterAppDelegate* delegate = [self delegate];
-  if (!delegate || ![delegate respondsToSelector:@selector(terminationHandler)] ||
-      [delegate terminationHandler] == nil) {
-    // If there's no termination handler, then just terminate.
-    [super terminate:sender];
-  }
-  FlutterEngineTerminationHandler* terminationHandler =
-      [static_cast<FlutterAppDelegate*>([self delegate]) terminationHandler];
-  [terminationHandler requestApplicationTermination:sender
-                                           exitType:kFlutterAppExitTypeCancelable
-                                             result:nil];
-  // Return, don't exit. The application delegate is responsible for exiting on
-  // its own by calling |terminateApplication|.
-}
-
-// Starts the regular Cocoa application termination flow, so that plugins will
-// get the appropriate notifications after the application has already decided
-// to quit. This is called after the application has decided that
-// it's OK to terminate.
-- (void)terminateApplication:(id)sender {
-  [super terminate:sender];
-}
 @end

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

@@ -13,9 +13,7 @@
 #include "flutter/shell/platform/embedder/embedder.h"
 
 #import "flutter/shell/platform/darwin/macos/framework/Headers/FlutterAppDelegate.h"
-#import "flutter/shell/platform/darwin/macos/framework/Headers/FlutterApplication.h"
 #import "flutter/shell/platform/darwin/macos/framework/Source/FlutterAppDelegate_Internal.h"
-#import "flutter/shell/platform/darwin/macos/framework/Source/FlutterApplication_Internal.h"
 #import "flutter/shell/platform/darwin/macos/framework/Source/FlutterCompositor.h"
 #import "flutter/shell/platform/darwin/macos/framework/Source/FlutterDartProject_Internal.h"
 #import "flutter/shell/platform/darwin/macos/framework/Source/FlutterMenuPlugin.h"
@@ -176,15 +174,11 @@ - (instancetype)initWithEngine:(FlutterEngine*)engine
   _terminator = terminator ? terminator : ^(id sender) {
     // Default to actually terminating the application. The terminator exists to
     // allow tests to override it so that an actual exit doesn't occur.
-    FlutterApplication* flutterApp = [FlutterApplication sharedApplication];
-    if (flutterApp && [flutterApp respondsToSelector:@selector(terminateApplication:)]) {
-      [[FlutterApplication sharedApplication] terminateApplication:sender];
-    } else if (flutterApp) {
-      [flutterApp terminate:sender];
-    }
+    NSApplication* flutterApp = [NSApplication sharedApplication];
+    [flutterApp terminate:sender];
   };
   FlutterAppDelegate* appDelegate =
-      (FlutterAppDelegate*)[[FlutterApplication sharedApplication] delegate];
+      (FlutterAppDelegate*)[[NSApplication sharedApplication] delegate];
   appDelegate.terminationHandler = self;
   return self;
 }
@@ -202,7 +196,7 @@ - (void)handleRequestAppExitMethodCall:(NSDictionary<NSString*, id>*)arguments
   FlutterAppExitType exitType =
       [type isEqualTo:@"cancelable"] ? kFlutterAppExitTypeCancelable : kFlutterAppExitTypeRequired;
 
-  [self requestApplicationTermination:[FlutterApplication sharedApplication]
+  [self requestApplicationTermination:[NSApplication sharedApplication]
                              exitType:exitType
                                result:result];
 }
@@ -212,6 +206,7 @@ - (void)handleRequestAppExitMethodCall:(NSDictionary<NSString*, id>*)arguments
 - (void)requestApplicationTermination:(id)sender
                              exitType:(FlutterAppExitType)type
                                result:(nullable FlutterResult)result {
+  _shouldTerminate = YES;
   switch (type) {
     case kFlutterAppExitTypeCancelable: {
       FlutterJSONMethodCodec* codec = [FlutterJSONMethodCodec sharedInstance];
@@ -238,6 +233,8 @@ - (void)requestApplicationTermination:(id)sender
                    NSDictionary* replyArgs = (NSDictionary*)decoded_reply;
                    if ([replyArgs[@"response"] isEqual:@"exit"]) {
                      _terminator(sender);
+                   } else if ([replyArgs[@"response"] isEqual:@"cancel"]) {
+                     _shouldTerminate = NO;
                    }
                    if (result != nil) {
                      result(replyArgs);

shell/platform/darwin/macos/framework/Source/FlutterEngineTest.mm

@@ -14,7 +14,6 @@
 #include "flutter/shell/platform/common/accessibility_bridge.h"
 #import "flutter/shell/platform/darwin/common/framework/Headers/FlutterChannels.h"
 #import "flutter/shell/platform/darwin/macos/framework/Headers/FlutterAppDelegate.h"
-#import "flutter/shell/platform/darwin/macos/framework/Headers/FlutterApplication.h"
 #import "flutter/shell/platform/darwin/macos/framework/Source/FlutterEngineTestUtils.h"
 #import "flutter/shell/platform/darwin/macos/framework/Source/FlutterViewControllerTestUtils.h"
 #include "flutter/shell/platform/embedder/embedder.h"

shell/platform/darwin/macos/framework/Source/FlutterEngine_Internal.h

@@ -8,7 +8,6 @@
 
 #include <memory>
 
-#import "flutter/shell/platform/darwin/macos/framework/Headers/FlutterApplication.h"
 #import "flutter/shell/platform/darwin/macos/framework/Source/AccessibilityBridgeMac.h"
 #import "flutter/shell/platform/darwin/macos/framework/Source/FlutterCompositor.h"
 #import "flutter/shell/platform/darwin/macos/framework/Source/FlutterPlatformViewController.h"
@@ -52,11 +51,14 @@ typedef NS_ENUM(NSInteger, FlutterAppExitResponse) {
  * messages through the platform channel managed by the engine.
  */
 @interface FlutterEngineTerminationHandler : NSObject
+
+@property(nonatomic, readonly) BOOL shouldTerminate;
+
 - (instancetype)initWithEngine:(FlutterEngine*)engine
                     terminator:(nullable FlutterTerminationCallback)terminator;
 - (void)handleRequestAppExitMethodCall:(NSDictionary<NSString*, id>*)data
                                 result:(FlutterResult)result;
-- (void)requestApplicationTermination:(FlutterApplication*)sender
+- (void)requestApplicationTermination:(NSApplication*)sender
                              exitType:(FlutterAppExitType)type
                                result:(nullable FlutterResult)result;
 @end