[macOS] Implement dialog window (flutter#176893)

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---------

Co-authored-by: Matthew Kosarek <matt.kosarek@canonical.com>

Author: knopp

engine/src/flutter/shell/platform/darwin/macos/framework/Source/FlutterWindowController.h

@@ -41,7 +41,9 @@ struct FlutterWindowCreationRequest {
   struct FlutterWindowSize size;
   bool has_constraints;
   struct FlutterWindowConstraints constraints;
-  void (*on_close)();
+  int64_t parent_view_id;
+  void (*on_should_close)();
+  void (*on_will_close)();
   void (*notify_listeners)();
 };
 
@@ -54,6 +56,11 @@ int64_t InternalFlutter_WindowController_CreateRegularWindow(
     int64_t engine_id,
     const FlutterWindowCreationRequest* request);
 
+FLUTTER_DARWIN_EXPORT
+int64_t InternalFlutter_WindowController_CreateDialogWindow(
+    int64_t engine_id,
+    const FlutterWindowCreationRequest* request);
+
 FLUTTER_DARWIN_EXPORT
 void InternalFlutter_Window_Destroy(int64_t engine_id, void* window);
 

engine/src/flutter/shell/platform/darwin/macos/framework/Source/FlutterWindowController.mm

@@ -90,10 +90,14 @@ - (void)windowDidResignKey:(NSNotification*)notification {
 
 - (BOOL)windowShouldClose:(NSWindow*)sender {
   flutter::IsolateScope isolate_scope(*_isolate);
-  _creationRequest.on_close();
+  _creationRequest.on_should_close();
   return NO;
 }
 
+- (void)windowWillClose {
+  _creationRequest.on_will_close();
+}
+
 - (void)windowDidResize:(NSNotification*)notification {
   flutter::IsolateScope isolate_scope(*_isolate);
   _creationRequest.notify_listeners();
@@ -141,6 +145,59 @@ - (instancetype)init {
   return self;
 }
 
+- (FlutterViewIdentifier)createDialogWindow:(const FlutterWindowCreationRequest*)request {
+  FlutterViewController* c = [[FlutterViewController alloc] initWithEngine:_engine
+                                                                   nibName:nil
+                                                                    bundle:nil];
+
+  NSWindow* window = [[NSWindow alloc] init];
+  // If this is not set there will be double free on window close when
+  // using ARC.
+  [window setReleasedWhenClosed:NO];
+
+  window.contentViewController = c;
+  window.styleMask =
+      NSWindowStyleMaskResizable | NSWindowStyleMaskTitled | NSWindowStyleMaskClosable;
+  window.collectionBehavior = NSWindowCollectionBehaviorFullScreenAuxiliary;
+  if (request->has_size) {
+    [window flutterSetContentSize:request->size];
+  }
+  if (request->has_constraints) {
+    [window flutterSetConstraints:request->constraints];
+  }
+
+  FlutterWindowOwner* w = [[FlutterWindowOwner alloc] initWithWindow:window
+                                               flutterViewController:c
+                                                     creationRequest:*request];
+  window.delegate = w;
+  [_windows addObject:w];
+
+  NSWindow* parent = nil;
+
+  if (request->parent_view_id != 0) {
+    for (FlutterWindowOwner* owner in _windows) {
+      if (owner.flutterViewController.viewIdentifier == request->parent_view_id) {
+        parent = owner.window;
+        break;
+      }
+    }
+    if (parent == nil) {
+      FML_LOG(WARNING) << "Failed to find parent window for ID " << request->parent_view_id;
+    }
+  }
+
+  if (parent != nil) {
+    [parent beginCriticalSheet:window
+             completionHandler:^(NSModalResponse response){
+             }];
+  } else {
+    [window setIsVisible:YES];
+    [window makeKeyAndOrderFront:nil];
+  }
+
+  return c.viewIdentifier;
+}
+
 - (FlutterViewIdentifier)createRegularWindow:(const FlutterWindowCreationRequest*)request {
   FlutterViewController* c = [[FlutterViewController alloc] initWithEngine:_engine
                                                                    nibName:nil
@@ -182,11 +239,21 @@ - (void)destroyWindow:(NSWindow*)window {
   }
   if (owner != nil) {
     [_windows removeObject:owner];
+
+    for (NSWindow* win in owner.window.sheets) {
+      [self destroyWindow:win];
+    }
+
+    for (NSWindow* win in owner.window.childWindows) {
+      [self destroyWindow:win];
+    }
+
     // Make sure to unregister the controller from the engine and remove the FlutterView
     // before destroying the window and Flutter NSView.
     [owner.flutterViewController dispose];
     owner.window.delegate = nil;
     [owner.window close];
+    [owner windowWillClose];
   }
 }
 
@@ -210,6 +277,14 @@ int64_t InternalFlutter_WindowController_CreateRegularWindow(
   return [engine.windowController createRegularWindow:request];
 }
 
+int64_t InternalFlutter_WindowController_CreateDialogWindow(
+    int64_t engine_id,
+    const FlutterWindowCreationRequest* request) {
+  FlutterEngine* engine = [FlutterEngine engineForIdentifier:engine_id];
+  [engine enableMultiView];
+  return [engine.windowController createDialogWindow:request];
+}
+
 void InternalFlutter_Window_Destroy(int64_t engine_id, void* window) {
   NSWindow* w = (__bridge NSWindow*)window;
   FlutterEngine* engine = [FlutterEngine engineForIdentifier:engine_id];

engine/src/flutter/shell/platform/darwin/macos/framework/Source/FlutterWindowControllerTest.mm

@@ -59,7 +59,8 @@ void TearDown() {
   FlutterWindowCreationRequest request{
       .has_size = true,
       .size = {.width = 800, .height = 600},
-      .on_close = [] {},
+      .on_should_close = [] {},
+      .on_will_close = [] {},
       .notify_listeners = [] {},
   };
 
@@ -83,7 +84,8 @@ void TearDown() {
   FlutterWindowCreationRequest request{
       .has_size = true,
       .size = {.width = 800, .height = 600},
-      .on_close = [] {},
+      .on_should_close = [] {},
+      .on_will_close = [] {},
       .notify_listeners = [] {},
   };
 
@@ -125,7 +127,8 @@ void TearDown() {
   FlutterWindowCreationRequest request{
       .has_size = true,
       .size = {.width = 800, .height = 600},
-      .on_close = [] {},
+      .on_should_close = [] {},
+      .on_will_close = [] {},
       .notify_listeners = [] {},
   };
 
@@ -145,7 +148,8 @@ void TearDown() {
   FlutterWindowCreationRequest request{
       .has_size = true,
       .size = {.width = 800, .height = 600},
-      .on_close = [] {},
+      .on_should_close = [] {},
+      .on_will_close = [] {},
       .notify_listeners = [] {},
   };
 
@@ -164,7 +168,8 @@ void TearDown() {
   FlutterWindowCreationRequest request{
       .has_size = true,
       .size = {.width = 800, .height = 600},
-      .on_close = [] {},
+      .on_should_close = [] {},
+      .on_will_close = [] {},
       .notify_listeners = [] {},
   };