From 75b0117dfbbedea75fd91e4ced8d24e499db4b07 Mon Sep 17 00:00:00 2001
From: Rico Tzschichholz <ricotz@ubuntu.com>
Date: Wed, 26 May 2021 18:39:20 +0200
Subject: [PATCH] codegen: Implementing GLib.Source.prepare/check is optional
 since 2.36

---
 codegen/valaccodemethodcallmodule.vala | 19 ++++++++++++++++++-
 tests/objects/gsource.vala             |  7 +++++++
 vapi/glib-2.0.vapi                     | 11 ++++++++---
 3 files changed, 33 insertions(+), 4 deletions(-)

diff --git a/codegen/valaccodemethodcallmodule.vala b/codegen/valaccodemethodcallmodule.vala
index bbd08e00f..ceb9370ec 100644
--- a/codegen/valaccodemethodcallmodule.vala
+++ b/codegen/valaccodemethodcallmodule.vala
@@ -188,10 +188,27 @@ public class Vala.CCodeMethodCallModule : CCodeAssignmentModule {
 				// g_source_new
 
 				string class_prefix = get_ccode_lower_case_name (current_class);
+				string prepare_func = "NULL";
+				string check_func = "NULL";
+				foreach (Method impl in current_class.get_methods ()) {
+					if (!impl.overrides) {
+						continue;
+					}
+					switch (impl.name) {
+					case "prepare":
+						prepare_func = "%s_real_prepare".printf (class_prefix);
+						break;
+					case "check":
+						check_func = "%s_real_check".printf (class_prefix);
+						break;
+					default:
+						break;
+					}
+				}
 
 				var funcs = new CCodeDeclaration ("const GSourceFuncs");
 				funcs.modifiers = CCodeModifiers.STATIC;
-				funcs.add_declarator (new CCodeVariableDeclarator ("_source_funcs", new CCodeConstant ("{ %s_real_prepare, %s_real_check, %s_real_dispatch, %s_finalize}".printf (class_prefix, class_prefix, class_prefix, class_prefix))));
+				funcs.add_declarator (new CCodeVariableDeclarator ("_source_funcs", new CCodeConstant ("{ %s, %s, %s_real_dispatch, %s_finalize}".printf (prepare_func, check_func, class_prefix, class_prefix))));
 				ccode.add_statement (funcs);
 
 				ccall.add_argument (new CCodeCastExpression (new CCodeUnaryExpression (CCodeUnaryOperator.ADDRESS_OF, new CCodeIdentifier ("_source_funcs")), "GSourceFuncs *"));
diff --git a/tests/objects/gsource.vala b/tests/objects/gsource.vala
index 753d2c4d9..e1f4f07a3 100644
--- a/tests/objects/gsource.vala
+++ b/tests/objects/gsource.vala
@@ -34,7 +34,14 @@ class BarSource : Source {
 	}
 }
 
+class ManamSource : Source {
+	public override bool dispatch (SourceFunc? callback) {
+		return false;
+	}
+}
+
 void main () {
 	var foo = new FooSource ();
 	var bar = new BarSource (1000);
+	var manam = new ManamSource ();
 }
diff --git a/vapi/glib-2.0.vapi b/vapi/glib-2.0.vapi
index 2a1456028..140d46a5d 100644
--- a/vapi/glib-2.0.vapi
+++ b/vapi/glib-2.0.vapi
@@ -2119,8 +2119,13 @@ namespace GLib {
 		[CCode (cname = "G_SOURCE_REMOVE")]
 		public const bool REMOVE;
 
+#if VALA_0_18
+		protected virtual bool prepare (out int timeout_);
+		protected virtual bool check ();
+#else
 		protected abstract bool prepare (out int timeout_);
 		protected abstract bool check ();
+#endif
 		protected abstract bool dispatch (SourceFunc? _callback);
 	}
 
@@ -2138,10 +2143,10 @@ namespace GLib {
 
 	[CCode (has_type_id = false)]
 	public struct SourceFuncs {
-		public SourcePrepareFunc prepare;
-		public SourceCheckFunc check;
+		public SourcePrepareFunc? prepare;
+		public SourceCheckFunc? check;
 		public SourceDispatchFunc dispatch;
-		public SourceFinalizeFunc finalize;
+		public SourceFinalizeFunc? finalize;
 	}
 
 	[CCode (has_target = false)]
-- 
2.47.2