[generator] Generate more [SupportedOSPlatform] attributes (#868)

Fixes: #863

In commits da12df4 and 412e974 (and others) we added support to
emit the `[SupportedOSPlatformAttribute]` custom attribute when
targeting .NET 6+ builds, using the Android API-level that the member
was introduced:

	[global::System.Runtime.Versioning.SupportedOSPlatformAttribute ("android23.0")]
	[global::Android.Runtime.Register ("android/telecom/InCallService", DoNotGenerateAcw=true, ApiSince = 23)]
	public abstract partial class InCallService : Android.App.Service {
	}

However, our "invoke" machinery uses this API without having the same
guards:

	[global::Android.Runtime.Register ("android/telecom/InCallService", DoNotGenerateAcw=true, ApiSince = 23)]
	internal partial class InCallServiceInvoker : InCallService {
	}

This results in build warnings when building e.g.
`xamarin-android/src/Mono.Android`:

	…/xamarin-android/src/Mono.Android/obj/Release/net6.0/android-30/mcw/Android.Telecom.InCallService.cs(1287,76):
	warning CA1416: This call site is reachable on all platforms. 'InCallService' is only supported on: 'android' 23.0 and later.

To fix these warnings, we need to emit the same
`[SupportedOSPlatformAttribute]` for these members as well:

	[global::System.Runtime.Versioning.SupportedOSPlatformAttribute ("android23.0")]
	[global::Android.Runtime.Register ("android/telecom/InCallService", DoNotGenerateAcw=true, ApiSince = 23)]
	internal partial class InCallServiceInvoker : InCallService {
	}

This change removes 4,699 `CA1416` warnings from our
`Mono.Android.dll` build.

The remaining 61 `CA1416` warnings are of the form:

	…\xamarin-android\src\Mono.Android\obj\Debug\net6.0\android-31\mcw\Java.Lang.Reflect.Method.cs(35,71):
	warning CA1416: This call site is reachable on all platforms. 'Executable' is only supported on: 'android' 26.0 and later.

The problem here is that `Java.Lang.Reflect.Method` class is available
since API-1, but it inherits from the `Java.Lang.Reflect.Executable`
class which was added in API-26.

See:

  - https://developer.android.com/reference/java/lang/reflect/Method
  - https://developer.android.com/reference/java/lang/reflect/Executable

This seems like a `Mono.Android.dll` issue and not something we should
attempt to fix in `generator`.

Author: jpobst

tools/generator/SourceWriters/BoundMethodExtensionStringOverload.cs

@@ -29,6 +29,8 @@ public BoundMethodExtensionStringOverload (Method method, CodeGenerationOptions
 			if (method.Deprecated != null)
 				Attributes.Add (new ObsoleteAttr (method.Deprecated.Replace ("\"", "\"\"").Trim ()));
 
+			SourceWriterExtensions.AddSupportedOSPlatform (Attributes, method, opt);
+
 			Parameters.Add (new MethodParameterWriter ("self", new TypeReferenceWriter (selfType)) { IsExtension = true });
 			this.AddMethodParametersStringOverloads (method.Parameters, opt);
 		}

tools/generator/SourceWriters/BoundMethodStringOverload.cs

@@ -27,6 +27,8 @@ public BoundMethodStringOverload (Method method, CodeGenerationOptions opt)
 			if (method.Deprecated != null)
 				Attributes.Add (new ObsoleteAttr (method.Deprecated.Replace ("\"", "\"\"").Trim ()));
 
+			SourceWriterExtensions.AddSupportedOSPlatform (Attributes, method, opt);
+
 			method.JavadocInfo?.AddJavadocs (Comments);
 
 			this.AddMethodParametersStringOverloads (method.Parameters, opt);

tools/generator/SourceWriters/BoundProperty.cs

@@ -69,13 +69,13 @@ public BoundProperty (GenBase gen, Property property, CodeGenerationOptions opt,
 			if (property.Getter.Deprecated != null && (property.Setter == null || property.Setter.Deprecated != null))
 				Attributes.Add (new ObsoleteAttr (property.Getter.Deprecated.Replace ("\"", "\"\"").Trim () + (property.Setter != null && property.Setter.Deprecated != property.Getter.Deprecated ? " " + property.Setter.Deprecated.Replace ("\"", "\"\"").Trim () : null)));
 
+			SourceWriterExtensions.AddSupportedOSPlatform (Attributes, property.Getter, opt);
+
 			SourceWriterExtensions.AddMethodCustomAttributes (GetterAttributes, property.Getter);
 
 			if (gen.IsGeneratable)
 				GetterComments.Add ($"// Metadata.xml XPath method reference: path=\"{gen.MetadataXPathReference}/method[@name='{property.Getter.JavaName}'{property.Getter.Parameters.GetMethodXPathPredicate ()}]\"");
 
-			SourceWriterExtensions.AddSupportedOSPlatform (GetterAttributes, property.Getter, opt);
-
 			GetterAttributes.Add (new RegisterAttr (property.Getter.JavaName, property.Getter.JniSignature, property.Getter.IsVirtual ? property.Getter.GetConnectorNameFull (opt) : string.Empty, additionalProperties: property.Getter.AdditionalAttributeString ()));
 
 			SourceWriterExtensions.AddMethodBody (GetBody, property.Getter, opt);

tools/generator/SourceWriters/BoundPropertyStringVariant.cs

@@ -24,6 +24,8 @@ public BoundPropertyStringVariant (Property property, CodeGenerationOptions opt)
 
 			SetVisibility ((property.Setter ?? property.Getter).Visibility);
 
+			SourceWriterExtensions.AddSupportedOSPlatform (Attributes, property.Getter, opt);
+
 			HasGet = true;
 
 			if (is_array)

tools/generator/SourceWriters/ClassInvokerClass.cs

@@ -26,6 +26,8 @@ public ClassInvokerClass (ClassGen klass, CodeGenerationOptions opt)
 
 			Attributes.Add (new RegisterAttr (klass.RawJniName, noAcw: true, additionalProperties: klass.AdditionalAttributeString ()) { UseGlobal = true });
 
+			SourceWriterExtensions.AddSupportedOSPlatform (Attributes, klass, opt);
+
 			var ctor = new ConstructorWriter {
 				Name = Name,
 				IsPublic = true,

tools/generator/SourceWriters/Extensions/SourceWriterExtensions.cs

@@ -85,7 +85,7 @@ public static void AddInterfaceListenerEventsAndProperties (TypeWriter tw, Inter
 
 					AddInterfaceListenerEventsAndProperties (tw, iface, target, name, setter,
 						string.Format ("__v => {0} = __v", prop.Name),
-						string.Format ("__v => {0} = null", prop.Name), opt);
+						string.Format ("__v => {0} = null", prop.Name), opt, prop.Getter);
 				} else {
 					refs.Add (method.Name);
 					string rm = null;
@@ -103,7 +103,7 @@ public static void AddInterfaceListenerEventsAndProperties (TypeWriter tw, Inter
 
 					AddInterfaceListenerEventsAndProperties (tw, iface, target, name, method.Name,
 						method.Name,
-						remove, opt);
+						remove, opt, method);
 				}
 			}
 
@@ -113,7 +113,9 @@ public static void AddInterfaceListenerEventsAndProperties (TypeWriter tw, Inter
 			tw.Methods.Add (new CreateImplementorMethod (iface, opt));
 		}
 
-		public static void AddInterfaceListenerEventsAndProperties (TypeWriter tw, InterfaceGen iface, ClassGen target, string name, string connector_fmt, string add, string remove, CodeGenerationOptions opt)
+		// Parameter 'setListenerMethod' refers to the method used to set the listener, like 'addOnRoutingChangedListener'/'setOnRoutingChangedListener'.
+		// This is used to determine what API level the listener setter is available on.
+		public static void AddInterfaceListenerEventsAndProperties (TypeWriter tw, InterfaceGen iface, ClassGen target, string name, string connector_fmt, string add, string remove, CodeGenerationOptions opt, Method setListenerMethod)
 		{
 			if (!iface.IsValid)
 				return;
@@ -128,11 +130,11 @@ public static void AddInterfaceListenerEventsAndProperties (TypeWriter tw, Inter
 				if (target.ContainsName (nameUnique))
 					nameUnique += "Event";
 
-				AddInterfaceListenerEventOrProperty (tw, iface, method, target, nameUnique, connector_fmt, add, remove, opt);
+				AddInterfaceListenerEventOrProperty (tw, iface, method, target, nameUnique, connector_fmt, add, remove, opt, setListenerMethod);
 			}
 		}
 
-		public static void AddInterfaceListenerEventOrProperty (TypeWriter tw, InterfaceGen iface, Method method, ClassGen target, string name, string connector_fmt, string add, string remove, CodeGenerationOptions opt)
+		public static void AddInterfaceListenerEventOrProperty (TypeWriter tw, InterfaceGen iface, Method method, ClassGen target, string name, string connector_fmt, string add, string remove, CodeGenerationOptions opt, Method setListenerMethod)
 		{
 			if (method.EventName == string.Empty)
 				return;
@@ -157,7 +159,7 @@ public static void AddInterfaceListenerEventOrProperty (TypeWriter tw, Interface
 					var mt = target.Methods.Where (method => string.Compare (method.Name, connector_fmt, StringComparison.OrdinalIgnoreCase) == 0 && method.IsListenerConnector).FirstOrDefault ();
 					var hasHandlerArgument = mt != null && mt.IsListenerConnector && mt.Parameters.Count == 2 && mt.Parameters [1].Type == "Android.OS.Handler";
 
-					tw.Events.Add (new InterfaceListenerEvent (iface, name, nameSpec, full_delegate_name, connector_fmt, add, remove, hasHandlerArgument, opt));
+					tw.Events.Add (new InterfaceListenerEvent (iface, setListenerMethod, name, nameSpec, full_delegate_name, connector_fmt, add, remove, hasHandlerArgument, opt));
 				}
 			} else {
 				if (opt.GetSafeIdentifier (name) != name) {

tools/generator/SourceWriters/InterfaceInvokerMethod.cs

@@ -30,6 +30,8 @@ public InterfaceInvokerMethod (InterfaceGen iface, Method method, CodeGeneration
 			method_callback = new MethodCallback (iface, method, opt, null, method.IsReturnCharSequence);
 			context_this = context.ContextType.GetObjectHandleProperty ("this");
 
+			SourceWriterExtensions.AddSupportedOSPlatform (Attributes, method, opt);
+
 			this.AddMethodParameters (method.Parameters, opt);
 		}
 

tools/generator/SourceWriters/InterfaceInvokerProperty.cs

@@ -27,6 +27,8 @@ public InterfaceInvokerProperty (InterfaceGen iface, Property property, CodeGene
 			IsPublic = true;
 			IsUnsafe = true;
 
+			SourceWriterExtensions.AddSupportedOSPlatform (Attributes, property.Getter, opt);
+
 			HasGet = property.Getter != null;
 
 			if (property.Getter != null) {

tools/generator/SourceWriters/InterfaceListenerEvent.cs

@@ -12,13 +12,15 @@ public class InterfaceListenerEvent : EventWriter
 	{
 		readonly InterfaceListenerEventHandlerHelper helper_method;
 
-		public InterfaceListenerEvent (InterfaceGen iface, string name, string nameSpec, string fullDelegateName, string wrefSuffix, string add, string remove, bool hasHandlerArgument, CodeGenerationOptions opt)
+		public InterfaceListenerEvent (InterfaceGen iface, Method method, string name, string nameSpec, string fullDelegateName, string wrefSuffix, string add, string remove, bool hasHandlerArgument, CodeGenerationOptions opt)
 		{
 			Name = name;
 			EventType = new TypeReferenceWriter (opt.GetOutputName (fullDelegateName));
 
 			IsPublic = true;
 
+			SourceWriterExtensions.AddSupportedOSPlatform (Attributes, method, opt);
+
 			HasAdd = true;
 
 			AddBody.Add ($"global::Java.Interop.EventHelper.AddEventHandler<{opt.GetOutputName (iface.FullName)}, {opt.GetOutputName (iface.FullName)}Implementor>(");
@@ -36,7 +38,7 @@ public InterfaceListenerEvent (InterfaceGen iface, string name, string nameSpec,
 			RemoveBody.Add ($"__h => __h.{nameSpec}Handler -= value);");
 
 			if (hasHandlerArgument)
-				helper_method = new InterfaceListenerEventHandlerHelper (iface, add, opt);
+				helper_method = new InterfaceListenerEventHandlerHelper (iface, method, add, opt);
 		}
 
 		public override void Write (CodeWriter writer)
@@ -49,12 +51,14 @@ public override void Write (CodeWriter writer)
 
 	public class InterfaceListenerEventHandlerHelper : MethodWriter
 	{
-		public InterfaceListenerEventHandlerHelper (InterfaceGen iface, string add, CodeGenerationOptions opt)
+		public InterfaceListenerEventHandlerHelper (InterfaceGen iface, Method method, string add, CodeGenerationOptions opt)
 		{
 			Name = add + "_Event_With_Handler_Helper";
 			Parameters.Add (new MethodParameterWriter ("value", new TypeReferenceWriter (opt.GetOutputName (iface.FullName))));
 			ReturnType = TypeReferenceWriter.Void;
 
+			SourceWriterExtensions.AddSupportedOSPlatform (Attributes, method, opt);
+
 			Body.Add ($"{add} (value, null);");
 		}
 	}

tools/generator/SourceWriters/MethodAsyncWrapper.cs

@@ -28,6 +28,8 @@ public MethodAsyncWrapper (Method method, CodeGenerationOptions opt)
 			if (!method.IsVoid)
 				ReturnType.Name += "<" + opt.GetTypeReferenceName (method.RetVal) + ">";
 
+			SourceWriterExtensions.AddSupportedOSPlatform (Attributes, method, opt);
+
 			Body.Add ($"return global::System.Threading.Tasks.Task.Run (() => {method.AdjustedName} ({method.Parameters.GetCall (opt)}));");
 
 			this.AddMethodParameters (method.Parameters, opt);