From bab871f3a10c124465db5c47f1815bacd99e728f Mon Sep 17 00:00:00 2001
From: Rico Tzschichholz <ricotz@ubuntu.com>
Date: Thu, 3 Oct 2019 10:43:22 +0200
Subject: [PATCH] codegen: Allow passing/retrieving any delegate to/from
 varargs parameter

Initialize target/notify cvalues of delegate-typed arguments/result of
inferred varargs parameters and va_list.arg() calls.

Only the actual function pointer will be passed or retrieved. The target
and destroy values will be null.
---
 codegen/valaccodemethodcallmodule.vala | 24 +++++++++++++++++++++
 tests/Makefile.am                      |  1 +
 tests/methods/varargs-delegate.vala    | 30 ++++++++++++++++++++++++++
 3 files changed, 55 insertions(+)
 create mode 100644 tests/methods/varargs-delegate.vala

diff --git a/codegen/valaccodemethodcallmodule.vala b/codegen/valaccodemethodcallmodule.vala
index d41e2904d..3c3290092 100644
--- a/codegen/valaccodemethodcallmodule.vala
+++ b/codegen/valaccodemethodcallmodule.vala
@@ -475,6 +475,17 @@ public class Vala.CCodeMethodCallModule : CCodeAssignmentModule {
 					set_cvalue (arg, get_variable_cexpression (temp_var.name));
 					arg.target_value.value_type = arg.value_type;
 
+					if (arg.value_type is DelegateType && ((DelegateType) arg.value_type).delegate_symbol.has_target) {
+						// Initialize target/destroy cvalues to allow assignment of delegates from varargs
+						unowned GLibValue arg_value = (GLibValue) arg.target_value;
+						if (arg_value.delegate_target_cvalue == null) {
+							arg_value.delegate_target_cvalue = new CCodeConstant ("NULL");
+						}
+						if (arg_value.delegate_target_destroy_notify_cvalue == null) {
+							arg_value.delegate_target_destroy_notify_cvalue = new CCodeConstant ("NULL");
+						}
+					}
+
 					cexpr = new CCodeUnaryExpression (CCodeUnaryOperator.ADDRESS_OF, get_cvalue (arg));
 				} else {
 					cexpr = handle_struct_argument (null, arg, cexpr);
@@ -831,6 +842,19 @@ public class Vala.CCodeMethodCallModule : CCodeAssignmentModule {
 					// TODO avoid code duplication
 					result_type = expr.value_type;
 				}
+				if (st != null && get_ccode_name (st) == "va_list" && ma.member_name == "arg") {
+					if (result_type is DelegateType && ((DelegateType) result_type).delegate_symbol.has_target) {
+						set_cvalue (expr, null);
+						// Initialize target/destroy cvalues to allow assignment of delegates from varargs
+						unowned GLibValue arg_value = (GLibValue) expr.target_value;
+						if (arg_value.delegate_target_cvalue == null) {
+							arg_value.delegate_target_cvalue = new CCodeConstant ("NULL");
+						}
+						if (arg_value.delegate_target_destroy_notify_cvalue == null) {
+							arg_value.delegate_target_destroy_notify_cvalue = new CCodeConstant ("NULL");
+						}
+					}
+				}
 			}
 
 			if (m != null && m.get_format_arg_index () >= 0) {
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 068914630..f6b4c42a4 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -149,6 +149,7 @@ TESTS = \
 	methods/printf-invalid.test \
 	methods/printf-constructor.vala \
 	methods/printf-constructor-invalid.test \
+	methods/varargs-delegate.vala \
 	methods/varargs-delegate-without-target.vala \
 	methods/varargs-gvalue.vala \
 	methods/varargs-out.vala \
diff --git a/tests/methods/varargs-delegate.vala b/tests/methods/varargs-delegate.vala
new file mode 100644
index 000000000..a797d4c5d
--- /dev/null
+++ b/tests/methods/varargs-delegate.vala
@@ -0,0 +1,30 @@
+delegate string Foo ();
+
+string foo (void* data) {
+	return "foo";
+}
+
+void bar (int first, ...) {
+	assert (first == 23);
+	var args = va_list ();
+	Foo** out_func = args.arg ();
+	*out_func = (Foo*) foo;
+}
+
+void baz (int first, ...) {
+	assert (first == 42);
+	var args = va_list ();
+	Foo func = args.arg ();
+	assert (func () == "foo");
+}
+
+void main () {
+	{
+		Foo func;
+		bar (23, out func);
+		assert (func () == "foo");
+	}
+	{
+		baz (42, foo);
+	}
+}
-- 
2.47.2