[RGen] Implement the generation of the Notifications helper class.

src/rgen/Microsoft.Macios.Generator/Emitters/ClassEmitter.cs

@@ -219,7 +219,41 @@ void EmitProperties (in BindingContext context, TabbedWriter<StringWriter> class
 
 	void EmitNotifications (in ImmutableArray<Property> properties, TabbedWriter<StringWriter> classBlock)
 	{
-		// to be implemented, do not throw or tests will fail.
+		if (properties.Length == 0)
+			return;
+
+		// default values
+		const string defaultNotificationCenter = "NSNotificationCenter.DefaultCenter";
+		const string defaultEventArgument = "Foundation.NSNotificationEventArgs";
+
+		// add a space just to make it nicer to read
+		classBlock.WriteLine ();
+
+		// create a nested static class with the notification helpers
+		using (var notificationClass = classBlock.CreateBlock ("public static partial class Notifications", true)) {
+			notificationClass.WriteLine ();
+			// generate two methods per notification
+			foreach (var notification in properties) {
+				var count = 12; // == "Notification".Length;
+				var name = $"Observe{notification.Name [..^count]}";
+				var notificationCenter = notification.ExportFieldData?.FieldData.NotificationCenter ?? defaultNotificationCenter;
+				var eventType = notification.ExportFieldData?.FieldData.Type ?? defaultEventArgument;
+				// use the raw writer which makes it easier to read in this case
+				notificationClass.WriteRaw (
+@$"public static NSObject {name} (EventHandler<{eventType}> handler)
+{{
+	return {notificationCenter}.AddObserver ({notification.Name}, notification => handler (null, new {eventType} (notification)));
+}}
+
+public static NSObject {name} (NSObject objectToObserve, EventHandler<{eventType}> handler)
+{{
+	return {notificationCenter}.AddObserver ({notification.Name}, notification => handler (null, new {eventType} (notification)), objectToObserve);
+}}
+
+"
+);
+			}
+		}
 	}
 
 	/// <summary>

tests/rgen/Microsoft.Macios.Generator.Tests/Classes/ClassGenerationTests.cs

@@ -37,6 +37,10 @@ public class TestDataGenerator : BaseTestDataGenerator, IEnumerable<object []> {
 			(ApplePlatform.MacOSX, "AppKitPropertyTests", "AppKitPropertyTests.cs", "ExpectedAppKitPropertyTests.cs", null),
 			(ApplePlatform.MacOSX, "ThreadSafeAppKitPropertyTests", "ThreadSafeAppKitPropertyTests.cs", "ExpectedThreadSafeAppKitPropertyTests.cs", null),
 
+			(ApplePlatform.iOS, "NSUserDefaults", "NSUserDefaults.cs", "ExpectedNSUserDefaults.cs", null),
+			(ApplePlatform.TVOS, "NSUserDefaults", "NSUserDefaults.cs", "ExpectedNSUserDefaults.cs", null),
+			(ApplePlatform.MacCatalyst, "NSUserDefaults", "NSUserDefaults.cs", "ExpectedNSUserDefaults.cs", null),
+			(ApplePlatform.MacOSX, "NSUserDefaults", "NSUserDefaults.cs", "ExpectedNSUserDefaults.cs", null),
 		};
 
 		public IEnumerator<object []> GetEnumerator ()

tests/rgen/Microsoft.Macios.Generator.Tests/Classes/Data/ExpectedCIImage.cs

@@ -127,5 +127,20 @@ public static partial int FormatRGBA16Int
 			return Dlfcn.GetInt32 (Libraries.TestNamespace.Handle, "FormatRGBA16Int");
 		}
 	}
+
+	public static partial class Notifications
+	{
+
+		public static NSObject ObserveDidProcessEditing (EventHandler<Foundation.NSNotificationEventArgs> handler)
+		{
+			return NSNotificationCenter.DefaultCenter.AddObserver (DidProcessEditingNotification, notification => handler (null, new Foundation.NSNotificationEventArgs (notification)));
+		}
+
+		public static NSObject ObserveDidProcessEditing (NSObject objectToObserve, EventHandler<Foundation.NSNotificationEventArgs> handler)
+		{
+			return NSNotificationCenter.DefaultCenter.AddObserver (DidProcessEditingNotification, notification => handler (null, new Foundation.NSNotificationEventArgs (notification)), objectToObserve);
+		}
+
+	}
 	// TODO: add binding code here
 }

tests/rgen/Microsoft.Macios.Generator.Tests/Classes/Data/ExpectedNSUserDefaults.cs

@@ -0,0 +1,147 @@
+// <auto-generated />
+
+#nullable enable
+
+using Foundation;
+using ObjCBindings;
+using ObjCRuntime;
+using System;
+using System.ComponentModel;
+using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
+using System.Drawing;
+using System.Runtime.InteropServices;
+using System.Runtime.Versioning;
+using System.Threading.Tasks;
+
+namespace Foundation;
+
+[Register ("NSUserDefaults", true)]
+public partial class NSUserDefaults
+{
+	[BindingImpl (BindingImplOptions.GeneratedCode | BindingImplOptions.Optimizable)]
+	static readonly NativeHandle class_ptr = Class.GetHandle ("NSUserDefaults");
+
+	public override NativeHandle ClassHandle => class_ptr;
+
+	[BindingImpl (BindingImplOptions.GeneratedCode | BindingImplOptions.Optimizable)]
+	[DesignatedInitializer]
+	[Export ("init")]
+	public NSUserDefaults () : base (NSObjectFlag.Empty)
+	{
+		if (IsDirectBinding)
+			InitializeHandle (global::ObjCRuntime.Messaging.IntPtr_objc_msgSend (this.Handle, global::ObjCRuntime.Selector.GetHandle ("init")), "init");
+		else
+			InitializeHandle (global::ObjCRuntime.Messaging.IntPtr_objc_msgSendSuper (this.SuperHandle, global::ObjCRuntime.Selector.GetHandle ("init")), "init");
+	}
+
+	[BindingImpl (BindingImplOptions.GeneratedCode | BindingImplOptions.Optimizable)]
+	[EditorBrowsable (EditorBrowsableState.Advanced)]
+	protected NSUserDefaults (NSObjectFlag t) : base (t) {}
+
+	[BindingImpl (BindingImplOptions.GeneratedCode | BindingImplOptions.Optimizable)]
+	[EditorBrowsable (EditorBrowsableState.Advanced)]
+	protected internal NSUserDefaults (NativeHandle handle) : base (handle) {}
+
+	static Foundation.NSString? _CompletedInitialSyncNotification;
+
+	[BindingImpl (BindingImplOptions.GeneratedCode | BindingImplOptions.Optimizable)]
+	[Advice ("Use 'NSUserDefaults.Notifications.CompletedInitialSyncNotification' helper method instead.")]
+	public static partial Foundation.NSString CompletedInitialSyncNotification
+	{
+		get
+		{
+			if (_CompletedInitialSyncNotification is null)
+				_CompletedInitialSyncNotification = Dlfcn.GetStringConstant (Libraries.Foundation.Handle, "NSUbiquitousUserDefaultsCompletedInitialSyncNotification")!;
+			return _CompletedInitialSyncNotification;
+		}
+	}
+
+	static Foundation.NSString? _DidChangeAccountsNotification;
+
+	[BindingImpl (BindingImplOptions.GeneratedCode | BindingImplOptions.Optimizable)]
+	[Advice ("Use 'NSUserDefaults.Notifications.DidChangeAccountsNotification' helper method instead.")]
+	public static partial Foundation.NSString DidChangeAccountsNotification
+	{
+		get
+		{
+			if (_DidChangeAccountsNotification is null)
+				_DidChangeAccountsNotification = Dlfcn.GetStringConstant (Libraries.Foundation.Handle, "NSUbiquitousUserDefaultsDidChangeAccountsNotification")!;
+			return _DidChangeAccountsNotification;
+		}
+	}
+
+	static Foundation.NSString? _NoCloudAccountNotification;
+
+	[BindingImpl (BindingImplOptions.GeneratedCode | BindingImplOptions.Optimizable)]
+	[Advice ("Use 'NSUserDefaults.Notifications.NoCloudAccountNotification' helper method instead.")]
+	public static partial Foundation.NSString NoCloudAccountNotification
+	{
+		get
+		{
+			if (_NoCloudAccountNotification is null)
+				_NoCloudAccountNotification = Dlfcn.GetStringConstant (Libraries.Foundation.Handle, "NSUbiquitousUserDefaultsNoCloudAccountNotification")!;
+			return _NoCloudAccountNotification;
+		}
+	}
+
+	static Foundation.NSString? _SizeLimitExceededNotification;
+
+	[BindingImpl (BindingImplOptions.GeneratedCode | BindingImplOptions.Optimizable)]
+	[Advice ("Use 'NSUserDefaults.Notifications.SizeLimitExceededNotification' helper method instead.")]
+	public static partial Foundation.NSString SizeLimitExceededNotification
+	{
+		get
+		{
+			if (_SizeLimitExceededNotification is null)
+				_SizeLimitExceededNotification = Dlfcn.GetStringConstant (Libraries.Foundation.Handle, "NSUserDefaultsSizeLimitExceededNotification")!;
+			return _SizeLimitExceededNotification;
+		}
+	}
+
+	public static partial class Notifications
+	{
+
+		public static NSObject ObserveCompletedInitialSync (EventHandler<Foundation.MyNotificationArgs> handler)
+		{
+			return SharedWorkspace.NotificationCenter.AddObserver (CompletedInitialSyncNotification, notification => handler (null, new Foundation.MyNotificationArgs (notification)));
+		}
+
+		public static NSObject ObserveCompletedInitialSync (NSObject objectToObserve, EventHandler<Foundation.MyNotificationArgs> handler)
+		{
+			return SharedWorkspace.NotificationCenter.AddObserver (CompletedInitialSyncNotification, notification => handler (null, new Foundation.MyNotificationArgs (notification)), objectToObserve);
+		}
+
+		public static NSObject ObserveDidChangeAccounts (EventHandler<Foundation.MyNotificationArgs> handler)
+		{
+			return NSNotificationCenter.DefaultCenter.AddObserver (DidChangeAccountsNotification, notification => handler (null, new Foundation.MyNotificationArgs (notification)));
+		}
+
+		public static NSObject ObserveDidChangeAccounts (NSObject objectToObserve, EventHandler<Foundation.MyNotificationArgs> handler)
+		{
+			return NSNotificationCenter.DefaultCenter.AddObserver (DidChangeAccountsNotification, notification => handler (null, new Foundation.MyNotificationArgs (notification)), objectToObserve);
+		}
+
+		public static NSObject ObserveNoCloudAccount (EventHandler<Foundation.NSNotificationEventArgs> handler)
+		{
+			return SharedWorkspace.NotificationCenter.AddObserver (NoCloudAccountNotification, notification => handler (null, new Foundation.NSNotificationEventArgs (notification)));
+		}
+
+		public static NSObject ObserveNoCloudAccount (NSObject objectToObserve, EventHandler<Foundation.NSNotificationEventArgs> handler)
+		{
+			return SharedWorkspace.NotificationCenter.AddObserver (NoCloudAccountNotification, notification => handler (null, new Foundation.NSNotificationEventArgs (notification)), objectToObserve);
+		}
+
+		public static NSObject ObserveSizeLimitExceeded (EventHandler<Foundation.NSNotificationEventArgs> handler)
+		{
+			return NSNotificationCenter.DefaultCenter.AddObserver (SizeLimitExceededNotification, notification => handler (null, new Foundation.NSNotificationEventArgs (notification)));
+		}
+
+		public static NSObject ObserveSizeLimitExceeded (NSObject objectToObserve, EventHandler<Foundation.NSNotificationEventArgs> handler)
+		{
+			return NSNotificationCenter.DefaultCenter.AddObserver (SizeLimitExceededNotification, notification => handler (null, new Foundation.NSNotificationEventArgs (notification)), objectToObserve);
+		}
+
+	}
+	// TODO: add binding code here
+}

tests/rgen/Microsoft.Macios.Generator.Tests/Classes/Data/NSUserDefaults.cs

@@ -0,0 +1,34 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+using System;
+using System.Runtime.Versioning;
+using Foundation;
+using ObjCBindings;
+
+namespace Foundation
+
+public partial class MyNotificationArgs {
+
+}
+
+[BindingType<Class>]
+public partial class NSUserDefaults : NSObject {
+
+	// default values
+
+	[Field<Property> ("NSUserDefaultsSizeLimitExceededNotification", Flags = Property.Notification)]
+	public static partial NSString SizeLimitExceededNotification { get; }
+
+	// special notification center
+	[Field<Property> ("NSUbiquitousUserDefaultsNoCloudAccountNotification", Flags = Property.Notification, NotificationCenter = "SharedWorkspace.NotificationCenter")]
+	public static partial NSString NoCloudAccountNotification { get; }
+
+	// special args
+	[Field<Property> ("NSUbiquitousUserDefaultsDidChangeAccountsNotification", Flags = Property.Notification, Type = typeof (MyNotificationArgs))]
+	public static partial NSString DidChangeAccountsNotification { get; }
+
+	// full customization
+	[Field<Property> ("NSUbiquitousUserDefaultsCompletedInitialSyncNotification", Flags = Property.Notification, Type = typeof (MyNotificationArgs), NotificationCenter = "SharedWorkspace.NotificationCenter")]
+	public static partial NSString CompletedInitialSyncNotification { get; }
+}