glib: install interfaces earlier, override properties in class_init

GObject upstream has started disabling support for installing interfaces
in GTypes after they have already been initialized (class_init) [1], so
we need to add GInterfaces a bit earlier (*before* class_init starts).

As GLib.Object.OverrideProperty() cannot to be called before class_init
(because it receives a GObjectClass, not a GType) or after (because
otherwise class_init would complain about properties of an interface not
being defined), then we need to call it during class_init.

[1] http://bugzilla.gnome.org/687659

A good side-effect of this fix is that we no longer use the hacky uint
field 'idx' to track the properties count for each class; now it gets
moved to the ClassInitializer class, and thus can be non-static, which
makes a bit more sense (we leave the old OverrideProperty overload for
backwards compatibility).

Simplest way to test this is launching the sample/treemodeldemo.exe and
sample/custom-scrollable.exe in Ubuntu 13.04 beta (which has GLib 2.36).
Fixes https://bugzilla.xamarin.com/show_bug.cgi?id=11510

generator/InterfaceGen.cs

@@ -117,10 +117,6 @@ namespace GtkSharp.Generation {
 				}
 				sw.WriteLine ("\t\t\tMarshal.StructureToPtr (native_iface, ifaceptr, false);");
 			}
-
-			foreach (Property prop in Properties.Values) {
-					sw.WriteLine ("\t\t\tGLib.Object.OverrideProperty (data, \"" + prop.CName + "\");");
-			}
 			sw.WriteLine ("\t\t}");
 			sw.WriteLine ();
 		}

glib/GType.cs

@@ -37,10 +37,14 @@ namespace GLib {
 		IntPtr val;
 
 		struct GTypeInfo {
+
+			[UnmanagedFunctionPointer (CallingConvention.Cdecl)]
+			public delegate void ClassInitDelegate (IntPtr gobject_class_handle);
+
 			public ushort class_size;
 			public IntPtr base_init;
 			public IntPtr base_finalize;
-			public IntPtr class_init;
+			public ClassInitDelegate class_init;
 			public IntPtr class_finalize;
 			public IntPtr class_data;
 			public ushort instance_size;
@@ -356,19 +360,23 @@ namespace GLib {
 			return sb.ToString ();
 		}
 
-		internal static GType RegisterGObjectType (System.Type t)
+		internal static GType RegisterGObjectType (Object.ClassInitializer gobject_class_initializer)
 		{
-			GType parent_gtype = LookupGObjectType (t.BaseType);
+			GType parent_gtype = LookupGObjectType (gobject_class_initializer.Type.BaseType);
-			string name = BuildEscapedName (t);
+			string name = BuildEscapedName (gobject_class_initializer.Type);
+
 			IntPtr native_name = GLib.Marshaller.StringToPtrGStrdup (name);
 			GTypeQuery query;
 			g_type_query (parent_gtype.Val, out query);
 			GTypeInfo info = new GTypeInfo ();
 			info.class_size = (ushort) query.class_size;
 			info.instance_size = (ushort) query.instance_size;
+			info.class_init = gobject_class_initializer.ClassInit;
+
 			GType gtype = new GType (g_type_register_static (parent_gtype.Val, native_name, ref info, 0));
 			GLib.Marshaller.Free (native_name);
-			Register (gtype, t);
+			Register (gtype, gobject_class_initializer.Type);
+
 			return gtype;
 		}
 

glib/Object.cs

@@ -1,9 +1,11 @@
 // Object.cs - GObject class wrapper implementation
 //
 // Authors: Mike Kestner <mkestner@speakeasy.net>
+//          Andres G. Aragoneses <knocte@gmail.com>
 //
 // Copyright (c) 2001-2003 Mike Kestner
 // Copyright (c) 2004-2005 Novell, Inc.
+// Copyright (c) 2013 Andres G. Aragoneses
 //
 // This program is free software; you can redistribute it and/or
 // modify it under the terms of version 2 of the Lesser GNU General 
@@ -214,6 +216,112 @@ namespace GLib {
 			public IntPtr dummy7;
 		}
 
+		internal class ClassInitializer {
+
+			internal uint Idx { get; set; }
+			internal Type Type { get; private set; }
+			internal bool HandlersOverriden { get; private set; }
+
+			bool is_first_subclass;
+			private GType gtype;
+			private List<GInterfaceAdapter> adapters = new List<GInterfaceAdapter> ();
+
+			internal ClassInitializer (Type type)
+			{
+				Idx = 1;
+				Type = type;
+				gtype = GType.RegisterGObjectType (this);
+				is_first_subclass = gtype.GetBaseType () == gtype.GetThresholdType ();
+			}
+
+			internal GType Init ()
+			{
+				AddGInterfaces ();
+				gtype.EnsureClass (); //calls class_init
+
+				AddProperties (gtype, Type, is_first_subclass, this);
+				ConnectDefaultHandlers (gtype, Type);
+				InvokeTypeInitializers (gtype, Type);
+				AddInterfaceProperties (gtype, Type);
+				return gtype;
+			}
+
+			private void AddGInterfaces ()
+			{
+				foreach (Type iface in Type.GetInterfaces ()) {
+					if (!iface.IsDefined (typeof (GInterfaceAttribute), true))
+						continue;
+
+					GInterfaceAttribute attr = iface.GetCustomAttributes (typeof (GInterfaceAttribute), false) [0] as GInterfaceAttribute;
+					GInterfaceAdapter adapter = Activator.CreateInstance (attr.AdapterType, null) as GInterfaceAdapter;
+
+					if (!iface.IsAssignableFrom (Type.BaseType)) {
+						GInterfaceInfo info = adapter.Info;
+						info.Data = gtype.Val;
+						g_type_add_interface_static (gtype.Val, adapter.GType.Val, ref info);
+						adapters.Add (adapter);
+					}
+				}
+			}
+
+			internal void ClassInit (IntPtr gobject_class_handle)
+			{
+				bool override_ctor = is_first_subclass;
+
+				bool override_props = is_first_subclass || adapters.Count > 0;
+
+				OverrideHandlers (gobject_class_handle, override_ctor, override_props);
+
+				foreach (GInterfaceAdapter adapter in adapters) {
+					InitializeProperties (adapter, gobject_class_handle);
+				}
+			}
+
+			private void InitializeProperties (GInterfaceAdapter adapter, IntPtr gobject_class_handle)
+			{
+				foreach (PropertyInfo pinfo in adapter.GetType ().GetProperties (BindingFlags.Instance | BindingFlags.Public | BindingFlags.DeclaredOnly)) {
+					foreach (object attr in pinfo.GetCustomAttributes (typeof (PropertyAttribute), false)) {
+						if (pinfo.GetIndexParameters ().Length > 0)
+							throw new InvalidOperationException (String.Format ("Property {0} of type {1} cannot be overriden because its GLib.PropertyAttribute is expected to have one or more indexed parameters",
+							                                                    pinfo.Name, adapter.GetType ().FullName));
+
+						PropertyAttribute property_attr = attr as PropertyAttribute;
+						if (property_attr != null) {
+							OverrideProperty (gobject_class_handle, property_attr.Name);
+						}
+					}
+				}
+			}
+
+			void OverrideProperty (IntPtr declaring_class, string name)
+			{
+				Object.OverrideProperty (declaring_class, Idx++, name);
+				Idx++;
+			}
+
+			internal void OverrideHandlers (bool ctor, bool properties)
+			{
+				OverrideHandlers (gtype.GetClassPtr (), ctor, properties);
+			}
+
+			private void OverrideHandlers (IntPtr gobject_class_handle, bool ctor, bool properties)
+			{
+				if (HandlersOverriden || (ctor == false && properties == false))
+					return;
+
+				GObjectClass gobject_class = (GObjectClass)Marshal.PtrToStructure (gobject_class_handle, typeof(GObjectClass));
+				if (ctor) {
+					gobject_class.constructor_cb = GLib.Object.ConstructorHandler;
+				}
+				if (properties) {
+					gobject_class.get_prop_cb = GLib.Object.GetPropertyHandler;
+					gobject_class.set_prop_cb = GLib.Object.SetPropertyHandler;
+				}
+				Marshal.StructureToPtr (gobject_class, gobject_class_handle, false);
+				HandlersOverriden = true;
+			}
+		}
+
 		[UnmanagedFunctionPointer (CallingConvention.Cdecl)]
 		delegate IntPtr ConstructorDelegate (IntPtr gtype, uint n_construct_properties, IntPtr construct_properties);
 
@@ -262,10 +370,16 @@ namespace GLib {
 		[DllImport ("libgobject-2.0-0.dll", CallingConvention = CallingConvention.Cdecl)]
 		static extern void g_object_class_override_property (IntPtr klass, uint prop_id, IntPtr name);
 
-		public static void OverrideProperty (IntPtr declaring_class, string name)
+		public static void OverrideProperty (IntPtr oclass, uint property_id, string name)
 		{
 			IntPtr native_name = GLib.Marshaller.StringToPtrGStrdup (name);
-			g_object_class_override_property (declaring_class, idx, native_name);
+			g_object_class_override_property (oclass, property_id, native_name);
+		}
+
+		[Obsolete ("Use OverrideProperty(oclass,property_id,name)")]
+		public static void OverrideProperty (IntPtr declaring_class, string name)
+		{
+			OverrideProperty (declaring_class, idx, name);
 			idx++;
 		}
 
@@ -301,13 +415,13 @@ namespace GLib {
 			return pspec.Handle;
 		}
 
-		static void AddProperties (GType gtype, System.Type t, bool register_instance_prop, ref bool handlers_overridden)
+		static void AddProperties (GType gtype, System.Type t, bool register_instance_prop, ClassInitializer gobject_class_initializer)
 		{
 			if (register_instance_prop) {
 				IntPtr declaring_class = gtype.GetClassPtr ();
 				ParamSpec pspec = new ParamSpec ("gtk-sharp-managed-instance", "", "", GType.Pointer, ParamFlags.Writable | ParamFlags.ConstructOnly);
-				g_object_class_install_property (declaring_class, idx, pspec.Handle);
+				g_object_class_install_property (declaring_class, gobject_class_initializer.Idx, pspec.Handle);
-				idx++;
+				gobject_class_initializer.Idx++;
 			}
 
 			foreach (PropertyInfo pinfo in t.GetProperties (BindingFlags.Instance | BindingFlags.Public | BindingFlags.DeclaredOnly)) {
@@ -315,17 +429,11 @@ namespace GLib {
 					if(pinfo.GetIndexParameters().Length > 0)
 						throw(new InvalidOperationException(String.Format("GLib.RegisterPropertyAttribute cannot be applied to property {0} of type {1} because the property expects one or more indexed parameters", pinfo.Name, t.FullName)));
 
-					if (!handlers_overridden) {
+					gobject_class_initializer.OverrideHandlers (false, true);
-						IntPtr class_ptr = gtype.GetClassPtr ();
+
-						GObjectClass gobject_class = (GObjectClass) Marshal.PtrToStructure (class_ptr, typeof (GObjectClass));
-						gobject_class.get_prop_cb = GetPropertyHandler;
-						gobject_class.set_prop_cb = SetPropertyHandler;
-						Marshal.StructureToPtr (gobject_class, class_ptr, false);
-						handlers_overridden = true;
-					}
 					PropertyAttribute property_attr = attr as PropertyAttribute;
 					try {
-						IntPtr param_spec = RegisterProperty (gtype, property_attr.Name, property_attr.Nickname, property_attr.Blurb, idx, (GType) pinfo.PropertyType, pinfo.CanRead, pinfo.CanWrite);
+						IntPtr param_spec = RegisterProperty (gtype, property_attr.Name, property_attr.Nickname, property_attr.Blurb, gobject_class_initializer.Idx, (GType) pinfo.PropertyType, pinfo.CanRead, pinfo.CanWrite);
 						Type type = (Type)gtype;
 						Dictionary<IntPtr, PropertyInfo> gtype_properties;
 						if (!Properties.TryGetValue (type, out gtype_properties)) {
@@ -333,7 +441,7 @@ namespace GLib {
 							Properties [type] = gtype_properties;
 						}
 						gtype_properties.Add (param_spec, pinfo);
-						idx++;
+						gobject_class_initializer.Idx++;
 					} catch (ArgumentException) {
 						throw new InvalidOperationException (String.Format ("GLib.PropertyAttribute cannot be applied to property {0} of type {1} because the return type of the property is not supported", pinfo.Name, t.FullName));
 					}
@@ -410,7 +518,7 @@ namespace GLib {
 		[DllImport ("libgobject-2.0-0.dll", CallingConvention = CallingConvention.Cdecl)]
 		static extern void g_type_add_interface_static (IntPtr gtype, IntPtr iface_type, ref GInterfaceInfo info);
 
-		static void AddInterfaces (GType gtype, Type t, ref bool handlers_overridden)
+		static void AddInterfaceProperties (GType gtype, Type t)
 		{
 			foreach (Type iface in t.GetInterfaces ()) {
 				if (!iface.IsDefined (typeof (GInterfaceAttribute), true))
@@ -418,23 +526,7 @@ namespace GLib {
 
 				GInterfaceAttribute attr = iface.GetCustomAttributes (typeof (GInterfaceAttribute), false) [0] as GInterfaceAttribute;
 				GInterfaceAdapter adapter = Activator.CreateInstance (attr.AdapterType, null) as GInterfaceAdapter;
-				if (!handlers_overridden) {
-					IntPtr class_ptr = gtype.GetClassPtr ();
-					GObjectClass gobject_class = (GObjectClass) Marshal.PtrToStructure (class_ptr, typeof (GObjectClass));
-					gobject_class.get_prop_cb = GetPropertyHandler;
-					gobject_class.set_prop_cb = SetPropertyHandler;
-					Marshal.StructureToPtr (gobject_class, class_ptr, false);
-					handlers_overridden = true;
-				}
 
-				if (!iface.IsAssignableFrom (t.BaseType)) {
-					GInterfaceInfo info = adapter.Info;
-					info.Data = gtype.GetClassPtr ();
-					//FIXME:  overiding prop is done inside the init of interface adapter
-					// not sure that it is the good solution but 
-					// it is the only one I found without exception or loop
-					g_type_add_interface_static (gtype.Val, adapter.GType.Val, ref info);
-				}
 				foreach (PropertyInfo p in iface.GetProperties ()) {
 					PropertyAttribute[] attrs = p.GetCustomAttributes (typeof (PropertyAttribute), true) as PropertyAttribute [];
 					if (attrs.Length == 0)
@@ -457,24 +549,11 @@ namespace GLib {
 
 		protected internal static GType RegisterGType (System.Type t)
 		{
-			GType gtype = GType.RegisterGObjectType (t);
+			//this is a deprecated way of tracking a property counter,
-			bool is_first_subclass = gtype.GetBaseType () == gtype.GetThresholdType ();
+			//but we may still need it for backwards compatibility
-
-			if (is_first_subclass) {
-				IntPtr class_ptr = gtype.GetClassPtr ();
-				GObjectClass gobject_class = (GObjectClass) Marshal.PtrToStructure (class_ptr, typeof (GObjectClass));
-				gobject_class.constructor_cb = ConstructorHandler;
-				gobject_class.get_prop_cb = GetPropertyHandler;
-				gobject_class.set_prop_cb = SetPropertyHandler;
-				Marshal.StructureToPtr (gobject_class, class_ptr, false);
-			}
 			idx = 1;
-			bool handlers_overridden = is_first_subclass;
+
-			AddProperties (gtype, t, is_first_subclass, ref handlers_overridden);
+			return new ClassInitializer (t).Init ();
-			ConnectDefaultHandlers (gtype, t);
-			InvokeTypeInitializers (gtype, t);
-			AddInterfaces (gtype, t, ref handlers_overridden);
-			return gtype;
 		}
 
 		protected GType LookupGType ()