codegen: Handle non-default AsyncResult parameter position

Unfortunately gdbus-codegen puts the AsyncResult parameter after possible
out-parameters therefore there is an "async_result_pos" attribute required
to handle this correctly.

Vala supposely follows the common practice to put the AsyncResult before
out-parameters by default.

Fixes https://gitlab.gnome.org/GNOME/vala/issues/709

10 files changed, 134 insertions, 8 deletions

diff --git a/codegen/valaccodebasemodule.vala b/codegen/valaccodebasemodule.vala
index d4c443124..9ea2e2c1b 100644
--- a/codegen/valaccodebasemodule.vala
+++ b/codegen/valaccodebasemodule.vala
@@ -4711,7 +4711,7 @@ public abstract class Vala.CCodeBaseModule : CodeGenerator {
 				// output arguments used separately
 				out_arg_map = new HashMap<int,CCodeExpression> (direct_hash, direct_equal);
 				// pass GAsyncResult stored in closure to finish function
-				out_arg_map.set (get_param_pos (0.1), new CCodeMemberAccess.pointer (new CCodeIdentifier ("_data_"), "_res_"));
+				out_arg_map.set (get_param_pos (get_ccode_async_result_pos (m)), new CCodeMemberAccess.pointer (new CCodeIdentifier ("_data_"), "_res_"));
 			}
 
 			if (cl != null && !cl.is_compact) {
@@ -6504,6 +6504,11 @@ public abstract class Vala.CCodeBaseModule : CodeGenerator {
 		return get_ccode_attribute(m).vfunc_name;
 	}
 
+	public static double get_ccode_async_result_pos (Method m) {
+		assert (m.coroutine);
+		return m.get_attribute_double ("CCode", "async_result_pos", 0.1);
+	}
+
 	public static string get_ccode_finish_name (Method m) {
 		return get_ccode_attribute(m).finish_name;
 	}
diff --git a/codegen/valaccodemethodcallmodule.vala b/codegen/valaccodemethodcallmodule.vala
index 187e1b01f..c188fb0ce 100644
--- a/codegen/valaccodemethodcallmodule.vala
+++ b/codegen/valaccodemethodcallmodule.vala
@@ -127,7 +127,7 @@ public class Vala.CCodeMethodCallModule : CCodeAssignmentModule {
 				// output arguments used separately
 				out_arg_map = new HashMap<int,CCodeExpression> (direct_hash, direct_equal);
 				// pass GAsyncResult stored in closure to finish function
-				out_arg_map.set (get_param_pos (0.1), new CCodeMemberAccess.pointer (new CCodeIdentifier ("_data_"), "_res_"));
+				out_arg_map.set (get_param_pos (get_ccode_async_result_pos (m)), new CCodeMemberAccess.pointer (new CCodeIdentifier ("_data_"), "_res_"));
 			}
 		}
 
diff --git a/codegen/valagasyncmodule.vala b/codegen/valagasyncmodule.vala
index 37ea7de08..6c706e8cf 100644
--- a/codegen/valagasyncmodule.vala
+++ b/codegen/valagasyncmodule.vala
@@ -603,7 +603,7 @@ public class Vala.GAsyncModule : GtkModule {
 
 		var cparam_map = new HashMap<int,CCodeParameter> (direct_hash, direct_equal);
 
-		cparam_map.set (get_param_pos (0.1), new CCodeParameter ("_res_", "GAsyncResult*"));
+		cparam_map.set (get_param_pos (get_ccode_async_result_pos (m)), new CCodeParameter ("_res_", "GAsyncResult*"));
 
 		generate_cparameters (m, cfile, cparam_map, finishfunc, null, null, null, 2);
 
@@ -902,9 +902,9 @@ public class Vala.GAsyncModule : GtkModule {
 					carg_map.set (get_param_pos (-0.9), new CCodeIdentifier ("_user_data_"));
 				}
 			} else if (direction == 2) {
-				cparam_map.set (get_param_pos (0.1), new CCodeParameter ("_res_", "GAsyncResult*"));
+				cparam_map.set (get_param_pos (get_ccode_async_result_pos (m)), new CCodeParameter ("_res_", "GAsyncResult*"));
 				if (carg_map != null) {
-					carg_map.set (get_param_pos (0.1), new CCodeIdentifier ("_res_"));
+					carg_map.set (get_param_pos (get_ccode_async_result_pos (m)), new CCodeIdentifier ("_res_"));
 				}
 			}
 		}
diff --git a/codegen/valagdbusclientmodule.vala b/codegen/valagdbusclientmodule.vala
index f2b199392..9939c501b 100644
--- a/codegen/valagdbusclientmodule.vala
+++ b/codegen/valagdbusclientmodule.vala
@@ -951,7 +951,7 @@ public class Vala.GDBusClientModule : GDBusModule {
 
 		var cparam_map = new HashMap<int,CCodeParameter> (direct_hash, direct_equal);
 
-		cparam_map.set (get_param_pos (0.1), new CCodeParameter ("_res_", "GAsyncResult*"));
+		cparam_map.set (get_param_pos (get_ccode_async_result_pos (m)), new CCodeParameter ("_res_", "GAsyncResult*"));
 
 		generate_cparameters (m, cfile, cparam_map, function, null, null, null, 2);
 
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 00bb4a45b..a63e38dfe 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -344,6 +344,7 @@ TESTS = \
 	asynchronous/bug793158.vala \
 	asynchronous/closures.vala \
 	asynchronous/generator.vala \
+	asynchronous/result-pos.vala \
 	asynchronous/yield.vala \
 	generics/bug694765-1.vala \
 	generics/bug694765-2.vala \
@@ -370,6 +371,7 @@ TESTS = \
 	gir/bug742012.test \
 	gir/bug788775.test \
 	gir/array-fixed-length.test \
+	gir/async-result-pos.test \
 	gir/delegate-alias-without-target.test \
 	annotations/deprecated.vala \
 	annotations/description.vala \
diff --git a/tests/asynchronous/result-pos.vala b/tests/asynchronous/result-pos.vala
new file mode 100644
index 000000000..3c86f75b5
--- /dev/null
+++ b/tests/asynchronous/result-pos.vala
@@ -0,0 +1,48 @@
+[CCode (async_result_pos = 2.1)]
+async void foo (int in_i, out int out_i) {
+	out_i = in_i;
+}
+
+[CCode (async_result_pos = 2.1)]
+async void bar (int in_i, out int out_i) throws Error {
+	out_i = in_i;
+}
+
+async void run () {
+	int i;
+	yield foo (323, out i);
+	assert (i == 323);
+	try {
+		yield bar (742, out i);
+		assert (i == 742);
+	} catch {
+		assert_not_reached ();
+	}
+	loop.quit ();
+}
+
+MainLoop loop;
+
+void main () {
+	loop = new MainLoop ();
+
+	foo.begin (23, (o,r) => {
+		int i;
+		foo.end (r, out i);
+		assert (i == 23);
+	});
+
+	bar.begin (42, (o,r) => {
+		try {
+			int i;
+			bar.end (r, out i);
+			assert (i == 42);
+		} catch {
+			assert_not_reached ();
+		}
+	});
+
+	run.begin ();
+
+	loop.run ();
+}
diff --git a/tests/gir/async-result-pos.test b/tests/gir/async-result-pos.test
new file mode 100644
index 000000000..2a17f53dc
--- /dev/null
+++ b/tests/gir/async-result-pos.test
@@ -0,0 +1,56 @@
+GIR
+
+Input:
+
+<class name="Foo" c:type="TestFoo" glib:type-name="TestFoo" glib:get-type="test_foo_get_type" glib:type-struct="FooClass" parent="GObject.Object">
+  <method name="method_async" c:identifier="test_foo_method_async">
+    <return-value transfer-ownership="none">
+      <type name="none"/>
+    </return-value>
+    <parameters>
+      <instance-parameter name="self" transfer-ownership="none">
+        <type name="Foo" c:type="TestFoo*"/>
+      </instance-parameter>
+      <parameter name="input" transfer-ownership="none">
+        <type name="utf8" c:type="const gchar*"/>
+      </parameter>
+      <parameter name="_callback_" transfer-ownership="none" allow-none="1" closure="2" scope="async">
+        <type name="Gio.AsyncReadyCallback" c:type="GAsyncReadyCallback"/>
+      </parameter>
+      <parameter name="_callback__target" transfer-ownership="none" allow-none="1">
+        <type name="gpointer" c:type="void*"/>
+      </parameter>
+    </parameters>
+  </method>
+  <method name="method_finish" c:identifier="test_foo_method_finish" throws="1">
+    <return-value transfer-ownership="full">
+      <type name="none"/>
+    </return-value>
+    <parameters>
+      <instance-parameter name="self" transfer-ownership="none">
+        <type name="Foo" c:type="TestFoo*"/>
+      </instance-parameter>
+      <parameter name="output" direction="out" transfer-ownership="full">
+        <type name="utf8" c:type="gchar**"/>
+      </parameter>
+      <parameter name="_res_" transfer-ownership="none">
+        <type name="Gio.AsyncResult" c:type="GAsyncResult*"/>
+      </parameter>
+    </parameters>
+  </method>
+  <constructor name="new" c:identifier="test_foo_new">
+    <return-value transfer-ownership="full">
+      <type name="Test.Foo" c:type="TestFoo*"/>
+    </return-value>
+  </constructor>
+</class>
+
+Output:
+
+[CCode (cheader_filename = "test.h", type_id = "test_foo_get_type ()")]
+public class Foo : GLib.Object {
+	[CCode (has_construct_function = false)]
+	public Foo ();
+	[CCode (async_result_pos = 2.1)]
+	public async void method_async (string input, out string output) throws GLib.Error;
+}
diff --git a/vala/valagirparser.vala b/vala/valagirparser.vala
index 948e9d13b..c9a9a576d 100644
--- a/vala/valagirparser.vala
+++ b/vala/valagirparser.vala
@@ -3823,6 +3823,7 @@ public class Vala.GirParser : CodeVisitor {
 
 		int i = 0, j=1;
 
+		int first_out = -1;
 		int last = -1;
 		foreach (ParameterInfo info in parameters) {
 			if (s is Delegate && info.closure_idx == i) {
@@ -3854,6 +3855,16 @@ public class Vala.GirParser : CodeVisitor {
 				// hidden parameters at the end of the parameter list
 				info.vala_idx = (j - 1) + (i - last) * 0.1F;
 			}
+			if (first_out < 0 && info.param.direction == ParameterDirection.OUT) {
+				first_out = i;
+			}
+			if (s is Method && first_out >= 0 && info.param.variable_type != null) {
+				var type_name = info.param.variable_type.to_string ();
+				if (type_name == "GLib.AsyncResult" || type_name == "Gio.AsyncResult") {
+					var shift = ((Method) s).binding == MemberBinding.INSTANCE ? 1.1 : 0.1;
+					s.set_attribute_double ("CCode", "async_result_pos", i + shift);
+				}
+			}
 			i++;
 		}
 
@@ -4093,6 +4104,8 @@ public class Vala.GirParser : CodeVisitor {
 				}
 			}
 
+			method.copy_attribute_double (finish_method, "CCode", "async_result_pos");
+
 			foreach (var param in finish_method.get_parameters ()) {
 				if (param.direction == ParameterDirection.OUT) {
 					var async_param = param.copy ();
diff --git a/vala/valamethod.vala b/vala/valamethod.vala
index 0190702cd..81ca7bb0d 100644
--- a/vala/valamethod.vala
+++ b/vala/valamethod.vala
@@ -978,6 +978,7 @@ public class Vala.Method : Subroutine, Callable {
 			foreach (var param in get_type_parameters ()) {
 				end_method.add_type_parameter (param);
 			}
+			end_method.copy_attribute_double (this, "CCode", "async_result_pos");
 		}
 		return end_method;
 	}
@@ -1042,7 +1043,7 @@ public class Vala.Method : Subroutine, Callable {
 		var result_type = new ObjectType ((ObjectTypeSymbol) glib_ns.scope.lookup ("AsyncResult"));
 
 		var result_param = new Parameter ("_res_", result_type);
-		result_param.set_attribute_double ("CCode", "pos", 0.1);
+		result_param.set_attribute_double ("CCode", "pos", get_attribute_double ("CCode", "async_result_pos", 0.1));
 		params.add (result_param);
 
 		foreach (var param in parameters) {
diff --git a/vala/valausedattr.vala b/vala/valausedattr.vala
index 5b6dcca5f..060594628 100644
--- a/vala/valausedattr.vala
+++ b/vala/valausedattr.vala
@@ -39,7 +39,8 @@ public class Vala.UsedAttr : CodeVisitor {
 		"has_copy_function", "lower_case_csuffix", "ref_sink_function", "dup_function", "finish_function", "generic_type_pos",
 		"array_length_type", "array_length", "array_length_cname", "array_length_cexpr", "array_null_terminated",
 		"vfunc_name", "finish_vfunc_name", "finish_name", "free_function_address_of", "pos", "delegate_target", "delegate_target_cname",
-		"array_length_pos", "delegate_target_pos", "destroy_notify_pos", "ctype", "has_new_function", "notify", "finish_instance", "",
+		"array_length_pos", "delegate_target_pos", "destroy_notify_pos", "ctype", "has_new_function", "notify", "finish_instance",
+		"async_result_pos", "",
 
 		"Immutable", "",
 		"Compact", "",