[foundation] Add support for NSValue/CGAffineTransform and StoreValueAtAddress overload (#6887)

Support for `NSValue`/`CGAffineTransform` exists in iOS/tvOS/watchOS,
from UIKit, but not for macOS. However this will be required for the
new protocols inside CoreImage.

Also add an overload for `StoreValueAtAddress` since the original
one was deprecated but we did not provide the new alternative to
update the code.

runtime/monotouch-support.h

@@ -1,4 +1,4 @@
-#ifndef __MONOTOUCH_SUPPORT_H__
+#ifndef __MONOTOUCH_SUPPORT_H__
 #define __MONOTOUCH_SUPPORT_H__
 
 #ifdef __cplusplus
@@ -15,6 +15,11 @@ void           xamarin_start_wwan (const char *uri);
 const char *   xamarin_GetFolderPath (int folder);
 #endif
 
+#ifdef MONOMAC
+const char *
+xamarin_encode_CGAffineTransform ();
+#endif
+
 #if defined (__arm64__)
 void objc_msgSend_stret (void);
 void objc_msgSendSuper_stret (void);

runtime/xamarin-support.m

@@ -172,3 +172,13 @@ void objc_msgSendSuper_stret (void)
 
 #endif
 
+#ifdef MONOMAC
+// <quote>Do not hard-code this parameter as a C string.</quote>
+// works on iOS (where we don't need it) and crash on macOS
+const char *
+xamarin_encode_CGAffineTransform ()
+{
+    // COOP: no managed memory access: any mode.
+    return @encode (CGAffineTransform);
+}
+#endif

src/Foundation/NSValue.cs

@@ -1,6 +1,7 @@
 //
 // Copyright 2010, Novell, Inc.
 // Copyright 2011, 2012, 2013 Xamarin Inc
+// Copyright 2019 Microsoft Corporation
 //
 // Permission is hereby granted, free of charge, to any person obtaining
 // a copy of this software and associated documentation files (the
@@ -22,11 +23,14 @@
 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 //
 
+using System;
 #if !NO_SYSTEM_DRAWING
 using System.Drawing;
 #endif
 using System.Runtime.InteropServices;
 
+using CoreGraphics;
+
 namespace Foundation {
 	public partial class NSValue : NSObject {
 #if !COREBUILD
@@ -64,6 +68,31 @@ namespace Foundation {
 			get { return (PointF)CGPointValue; }
 		}
 #endif
+
+#if MONOMAC
+		// @encode(CGAffineTransform) -> "{CGAffineTransform=dddddd}" but...
+		// using a C string crash on macOS (while it works fine on iOS)
+		[DllImport ("__Internal")]
+		extern static IntPtr xamarin_encode_CGAffineTransform ();
+
+		// The `+valueWithCGAffineTransform:` selector comes from UIKit and is not available on macOS
+		public unsafe static NSValue FromCGAffineTransform (CGAffineTransform tran)
+		{
+			return Create ((IntPtr) (void*) &tran, xamarin_encode_CGAffineTransform ());
+		}
+
+		// The `CGAffineTransformValue` selector comes from UIKit and is not available on macOS
+		public unsafe virtual CGAffineTransform CGAffineTransformValue {
+			get {
+				var result = new CGAffineTransform ();
+				// avoid potential buffer overflow since we use the older `getValue:` API to cover all platforms
+				// and we can cheat here with the actual string comparison (since we are the one doing it)
+				if (ObjCType == "{CGAffineTransform=dddddd}")
+					StoreValueAtAddress ((IntPtr) (void*) &result);
+				return result;
+			}
+		}
+#endif
 #endif
 	}
 }

src/foundation.cs

@@ -10879,14 +10879,19 @@ namespace Foundation
 		[Export ("getValue:")]
 		void StoreValueAtAddress (IntPtr value);
 
+		[Watch (4,0), TV (11,0), Mac (10,13), iOS (11,0)]
+		[Export ("getValue:size:")]
+		void StoreValueAtAddress (IntPtr value, nuint size);
+
 		[Export ("objCType")][Internal]
 		IntPtr ObjCTypePtr ();
 		
 		//[Export ("initWithBytes:objCType:")][Internal]
 		//NSValue InitFromBytes (IntPtr byte_ptr, IntPtr char_ptr_type);
-		//[Export ("valueWithBytes:objCType:")][Static][Internal]
-		//+ (NSValue *)valueWithBytes:(const void *)value objCType:(const char *)type;
-		//+ (NSValue *)value:(const void *)value withObjCType:(const char *)type;
+
+		[Static][Internal]
+		[Export ("valueWithBytes:objCType:")]
+		NSValue Create (IntPtr bytes, IntPtr objCType);
 
 		[Static]
 		[Export ("valueWithNonretainedObject:")]

tests/monotouch-test/CoreGraphics/AffineTransformTest.cs

@@ -5,6 +5,7 @@
 //	Rolf Bjarne Kvinge <rolf@xamarin.com>
 //
 // Copyright 2014 Xamarin Inc. All rights reserved.
+// Copyright 2019 Microsoft Corporation
 //
 
 using System;
@@ -334,6 +335,22 @@ namespace MonoTouchFixtures.CoreGraphics {
 			Assert.AreEqual ((nfloat) 1.0, transform.x0, "x0");
 			Assert.AreEqual ((nfloat) (-2.0), transform.y0, "y0");
 		}
+
+		[Test]
+		public void NSValueRoundtrip ()
+		{
+			var transform = new CGAffineTransform (1, 2, 3, 4, 5, 6);
+			// looks simplistic but that NSValue logic is implemented by "us" on macOS
+			using (var nsv = NSValue.FromCGAffineTransform (transform)) {
+				var tback = nsv.CGAffineTransformValue;
+				Assert.AreEqual ((nfloat)1, tback.xx, "xx");
+				Assert.AreEqual ((nfloat)2, tback.yx, "yx");
+				Assert.AreEqual ((nfloat)3, tback.xy, "xy");
+				Assert.AreEqual ((nfloat)4, tback.yy, "yy");
+				Assert.AreEqual ((nfloat)5, tback.x0, "x0");
+				Assert.AreEqual ((nfloat)6, tback.y0, "y0");
+			}
+		}
 	}
 
 

tests/xtro-sharpie/common-Foundation.ignore

@@ -417,7 +417,6 @@
 !missing-selector! +NSURLRequest::requestWithURL:cachePolicy:timeoutInterval: not bound
 !missing-selector! +NSURLRequest::supportsSecureCoding not bound
 !missing-selector! +NSValue::value:withObjCType: not bound
-!missing-selector! +NSValue::valueWithBytes:objCType: not bound
 !missing-selector! +NSXPCInterface::interfaceWithProtocol: not bound
 !missing-selector! NSArray::addObserver:forKeyPath:options:context: not bound
 !missing-selector! NSArray::arrayByAddingObject: not bound
@@ -837,7 +836,6 @@
 !missing-selector! NSURLProtocol::task not bound
 !missing-selector! NSURLRequest::HTTPShouldUsePipelining not bound
 !missing-selector! NSUUID::initWithUUIDBytes: not bound
-!missing-selector! NSValue::getValue:size: not bound
 !missing-selector! NSValue::initWithBytes:objCType: not bound
 !missing-selector! NSXPCConnection::auditSessionIdentifier not bound
 !missing-selector! NSXPCConnection::effectiveGroupIdentifier not bound