Fix support for delegates returning arrays of structs (#510)

Author: kennykerr

.gitignore

@@ -11,3 +11,4 @@ packages
 Debug
 Release
 Generated Files
+obj

cppwinrt/code_writers.h

@@ -965,7 +965,7 @@ namespace cppwinrt
         }
     }
 
-    static void write_consume_return_type(writer& w, method_signature const& signature)
+    static void write_consume_return_type(writer& w, method_signature const& signature, bool delegate_types)
     {
         if (!signature.return_signature())
         {
@@ -981,13 +981,15 @@ namespace cppwinrt
         %* %{};)";
 
             w.abi_types = true;
+            w.delegate_types = delegate_types;
 
             w.write(format,
                 signature.return_param_name(),
                 signature.return_signature(),
                 signature.return_param_name());
 
             w.abi_types = false;
+            w.delegate_types = false;
         }
         else if (category == param_category::object_type || category == param_category::string_type)
         {
@@ -1077,7 +1079,7 @@ namespace cppwinrt
             bind<write_comma_generic_types>(generics),
             method_name,
             bind<write_consume_params>(signature),
-            bind<write_consume_return_type>(signature),
+            bind<write_consume_return_type>(signature, false),
             type,
             get_abi_name(method),
             bind<write_abi_args>(signature),
@@ -2447,7 +2449,7 @@ struct __declspec(empty_bases) produce_dispatch_to_overridable<T, D, %>
                 type_name,
                 bind_list(", ", generics),
                 bind<write_consume_params>(signature),
-                bind<write_consume_return_type>(signature),
+                bind<write_consume_return_type>(signature, true),
                 type_name,
                 bind_list(", ", generics),
                 bind<write_abi_args>(signature),
@@ -2500,7 +2502,7 @@ struct __declspec(empty_bases) produce_dispatch_to_overridable<T, D, %>
                 type_name,
                 type_name,
                 bind<write_consume_params>(signature),
-                bind<write_consume_return_type>(signature),
+                bind<write_consume_return_type>(signature, true),
                 type_name,
                 bind<write_abi_args>(signature),
                 bind<write_consume_return_statement>(signature));

cppwinrt/type_writers.h

@@ -106,6 +106,7 @@ namespace cppwinrt
 
         std::string type_namespace;
         bool abi_types{};
+        bool delegate_types{};
         bool param_names{};
         bool consume_types{};
         bool async_types{};
@@ -276,6 +277,10 @@ namespace cppwinrt
                     {
                         write("@::%", ns, name);
                     }
+                    else if (delegate_types)
+                    {
+                        write("struct impl::struct_%_%", get_impl_name(ns), name);
+                    }
                     else
                     {
                         write("struct struct_%_%", get_impl_name(ns), name);

test/test/struct_delegate.cpp

@@ -0,0 +1,21 @@
+#include "pch.h"
+#include "winrt/test_component.delegates.h"
+
+using namespace winrt;
+using namespace test_component;
+
+TEST_CASE("struct_delegate")
+{
+    Delegates::StructDelegate d = []
+    {
+        return com_array{ Struct{ L"First", L"Second" }, Struct{ L"Third", L"Fourth" } };
+    };
+
+    auto values = d();
+
+    REQUIRE(values.size() == 2);
+    REQUIRE(values[0].First == L"First");
+    REQUIRE(values[0].Second == L"Second");
+    REQUIRE(values[1].First == L"Third");
+    REQUIRE(values[1].Second == L"Fourth");
+}

test/test/test.vcxproj

@@ -417,6 +417,7 @@
     <ClCompile Include="return_params_abi.cpp" />
     <ClCompile Include="single_threaded_observable_vector.cpp" />
     <ClCompile Include="structs.cpp" />
+    <ClCompile Include="struct_delegate.cpp" />
     <ClCompile Include="tearoff.cpp" />
     <ClCompile Include="thread_pool.cpp" />
     <ClCompile Include="uniform_in_params.cpp" />

test/test_component/test_component.idl

@@ -11,6 +11,12 @@ namespace Windows.Foundation.Metadata
 
 namespace test_component
 {
+    struct Struct
+    {
+        String First;
+        String Second;
+    };
+
     namespace Delegates
     {
         delegate void AgileDelegate();
@@ -22,6 +28,7 @@ namespace test_component
         delegate String[] ReturnStringArrayDelegate();
         delegate void OutStringArrayDelegate(out String[] value);
         delegate void RefStringArrayDelegate(ref String[] value);
+        delegate test_component.Struct[] StructDelegate();
     }
 
     enum Signed
@@ -39,12 +46,6 @@ namespace test_component
         Third = 2
     };
 
-    struct Struct
-    {
-        String First;
-        String Second;
-    };
-
     runtimeclass Simple
     {
         Simple();