[vision] Add nullability to (generated and manual) bindings

src/Vision/VNBarcodeSymbologyExtensions.cs

@@ -7,26 +7,28 @@
 // Copyright 2017 Xamarin Inc. All rights reserved.
 //
 
+#nullable enable
+
 using System;
 using Foundation;
 
 namespace Vision {
 	public static partial class VNBarcodeSymbologyExtensions {
 		public static NSString [] GetConstants (this VNBarcodeSymbology [] self)
 		{
-			if (self == null)
-				throw new ArgumentNullException (nameof (self));
+			if (self is null)
+				ObjCRuntime.ThrowHelper.ThrowArgumentNullException (nameof (self));
 
 			var array = new NSString [self.Length];
 			for (int n = 0; n < self.Length; n++)
-				array [n] = self [n].GetConstant ();
+				array [n] = self [n].GetConstant ()!;
 			return array;
 		}
 
-		public static VNBarcodeSymbology [] GetValues (NSString [] constants)
+		public static VNBarcodeSymbology [] GetValues (NSString []? constants)
 		{
-			if (constants == null)
-				throw new ArgumentNullException (nameof (constants));
+			if (constants is null)
+				ObjCRuntime.ThrowHelper.ThrowArgumentNullException (nameof (constants));
 
 			var array = new VNBarcodeSymbology [constants.Length];
 			for (int n = 0; n < constants.Length; n++)

src/Vision/VNCircle.cs

@@ -7,14 +7,16 @@
 // Copyright (c) Microsoft Corporation.
 //
 
+#nullable enable
+
 using System;
 using Foundation;
 using ObjCRuntime;
 
 namespace Vision {
 	public partial class VNCircle {
 
-		public static VNCircle CreateUsingRadius (VNPoint center, double radius)
+		public static VNCircle? CreateUsingRadius (VNPoint center, double radius)
 		{
 			var handle = Messaging.IntPtr_objc_msgSend (class_ptr, Selector.GetHandle ("alloc"));
 #if NET
@@ -25,7 +27,7 @@ public static VNCircle CreateUsingRadius (VNPoint center, double radius)
 			return Runtime.GetNSObject<VNCircle> (handle, true);
 		}
 
-		public static VNCircle CreateUsingDiameter (VNPoint center, double diameter)
+		public static VNCircle? CreateUsingDiameter (VNPoint center, double diameter)
 		{
 			var handle = Messaging.IntPtr_objc_msgSend (class_ptr, Selector.GetHandle ("alloc"));
 #if NET

src/Vision/VNCompat.cs

@@ -1,3 +1,5 @@
+#nullable enable
+
 #if !NET
 
 using System;
@@ -7,7 +9,7 @@ namespace Vision {
 	public partial class VNRequest {
 
 		[Obsolete ("Empty stub (not a public API).")]
-		public virtual IMTLDevice PreferredMetalContext { get; set; }
+		public virtual IMTLDevice? PreferredMetalContext { get; set; }
 	}
 }
 

src/Vision/VNDetectBarcodesRequest.cs

@@ -7,6 +7,8 @@
 // Copyright 2017 Xamarin Inc. All rights reserved.
 //
 
+#nullable enable
+
 using System;
 
 namespace Vision {

src/Vision/VNFaceLandmarkRegion2D.cs

@@ -7,13 +7,15 @@
 // Copyright 2017 Xamarin Inc. All rights reserved.
 //
 
+#nullable enable
+
 using System;
 using CoreGraphics;
 
 namespace Vision {
 	public partial class VNFaceLandmarkRegion2D {
 
-		public virtual CGPoint [] NormalizedPoints {
+		public virtual CGPoint []? NormalizedPoints {
 			get {
 				var ret = _GetNormalizedPoints ();
 				if (ret == IntPtr.Zero)
@@ -30,7 +32,7 @@ public virtual CGPoint [] NormalizedPoints {
 			}
 		}
 
-		public virtual CGPoint [] GetPointsInImage (CGSize imageSize)
+		public virtual CGPoint []? GetPointsInImage (CGSize imageSize)
 		{
 			// return the address of the array of pointCount points
 			// or NULL if the conversion could not take place.

src/Vision/VNFeaturePrintObservation.cs

@@ -7,14 +7,16 @@
 // Copyright 2019 Microsoft Corporation. All rights reserved.
 //
 
+#nullable enable
+
 using System;
 using Foundation;
 using ObjCRuntime;
 
 namespace Vision {
 	public partial class VNFeaturePrintObservation {
 
-		public bool ComputeDistance (out float [] distance, VNFeaturePrintObservation featurePrint, out NSError error)
+		public bool ComputeDistance (out float [] distance, VNFeaturePrintObservation featurePrint, out NSError? error)
 		{
 			distance = new float [ElementCount];
 			unsafe {

src/Vision/VNRecognizedPointsObservation.cs

@@ -7,21 +7,23 @@
 // Copyright (c) Microsoft Corporation.
 //
 
+#nullable enable
+
 using System;
 using Foundation;
 using ObjCRuntime;
 
 namespace Vision {
 	public partial class VNRecognizedPointsObservation {
 
-		public T [] GetAvailableKeys<T> () where T : Enum
+		public T []? GetAvailableKeys<T> () where T : Enum
 		{
 			var type = typeof (T);
 			if (!(type == typeof (VNHumanBodyPoseObservationJointName) || type == typeof (VNHumanHandPoseObservationJointName)))
 				throw new InvalidOperationException ($"Only '{nameof (VNHumanBodyPoseObservationJointName)}' and '{nameof (VNHumanHandPoseObservationJointName)}' are supported.");
 
 			NSString[] keys = AvailableKeys;
-			if (keys == null)
+			if (keys is null)
 				return null;
 
 			if (keys.Length == 0)
@@ -34,14 +36,14 @@ public T [] GetAvailableKeys<T> () where T : Enum
 			return null;
 		}
 
-		public T [] GetAvailableGroupKeys<T> () where T : Enum
+		public T []? GetAvailableGroupKeys<T> () where T : Enum
 		{
 			var type = typeof (T);
 			if (!(type == typeof (VNHumanBodyPoseObservationJointsGroupName) || type == typeof (VNHumanHandPoseObservationJointsGroupName)))
 				throw new InvalidOperationException ($"Only '{nameof (VNHumanBodyPoseObservationJointsGroupName)}' and '{nameof (VNHumanHandPoseObservationJointsGroupName)}' are supported.");
 
 			NSString[] keys = AvailableGroupKeys;
-			if (keys == null)
+			if (keys is null)
 				return null;
 
 			if (keys.Length == 0)

src/Vision/VNRequest.cs

@@ -7,6 +7,8 @@
 // Copyright 2017 Xamarin Inc. All rights reserved.
 //
 
+#nullable enable
+
 using System;
 using Foundation;
 using ObjCRuntime;

src/Vision/VNRequestRevision.cs

@@ -7,16 +7,18 @@
 // Copyright 2018 Microsoft Corporation.
 //
 
+#nullable enable
+
 using System;
 using Foundation;
 using ObjCRuntime;
 
 namespace Vision {
 	public partial class VNRequest {
 
-		internal static T [] GetSupportedVersions<T> (NSIndexSet indexSet) where T : Enum
+		internal static T []? GetSupportedVersions<T> (NSIndexSet indexSet) where T : Enum
 		{
-			if (indexSet == null)
+			if (indexSet is null)
 				return null;
 
 			var count = indexSet.Count;

src/Vision/VNUtils.cs

@@ -7,6 +7,8 @@
 // Copyright 2017 Xamarin Inc. All rights reserved.
 //
 
+#nullable enable
+
 using System;
 using System.Runtime.InteropServices;
 using CoreGraphics;
@@ -175,10 +177,10 @@ public static CGPoint GetImagePoint (Vector2 faceLandmarkPoint, CGRect faceBound
 
 	public partial class VNGeometryUtils {
 
-		public static VNCircle CreateBoundingCircle (Vector2 [] points, out NSError error)
+		public static VNCircle? CreateBoundingCircle (Vector2 [] points, out NSError error)
 		{
-			if (points == null)
-				throw new ArgumentNullException (nameof (points));
+			if (points is null)
+				ObjCRuntime.ThrowHelper.ThrowArgumentNullException (nameof (points));
 			if (points.Length == 0)
 				throw new ArgumentException ($"'{nameof (points)}' array must have more than zero elements.");
 

src/Vision/VNVector.cs

@@ -7,14 +7,16 @@
 // Copyright (c) Microsoft Corporation.
 //
 
+#nullable enable
+
 using System;
 using Foundation;
 using ObjCRuntime;
 
 namespace Vision {
 	public partial class VNVector {
 
-		public static VNVector Create (double r, double theta)
+		public static VNVector? Create (double r, double theta)
 		{
 			var handle = Messaging.IntPtr_objc_msgSend (class_ptr, Selector.GetHandle ("alloc"));
 			handle = Messaging.IntPtr_objc_msgSend_Double_Double (handle, Selector.GetHandle ("initWithR:theta:"), r, theta);