From 80de0969db963252ae3377e9bdb168623a2ca288 Mon Sep 17 00:00:00 2001
From: Kenny Kerr <kekerr@microsoft.com>
Date: Thu, 16 Jan 2020 14:18:05 -0800
Subject: [PATCH] Provide winrt_activation_handler to hook/mock activation
 (#477)

---
 strings/base_activation.h       |  5 ++++
 strings/base_extern.h           |  1 +
 test/test/custom_activation.cpp | 52 +++++++++++++++++++++++++++++++++
 test/test/test.vcxproj          | 10 +++++++
 4 files changed, 68 insertions(+)
 create mode 100644 test/test/custom_activation.cpp

diff --git a/strings/base_activation.h b/strings/base_activation.h
index c50effe94..37c70aaa9 100644
--- a/strings/base_activation.h
+++ b/strings/base_activation.h
@@ -21,6 +21,11 @@ namespace winrt::impl
     template <typename Interface>
     hresult get_runtime_activation_factory(param::hstring const& name, void** result) noexcept
     {
+        if (winrt_activation_handler)
+        {
+            return winrt_activation_handler(*(void**)(&name), guid_of<Interface>(), result);
+        }
+
         static int32_t(__stdcall * handler)(void* classId, guid const& iid, void** factory) noexcept;
 
         impl::load_runtime_function("RoGetActivationFactory", handler,
diff --git a/strings/base_extern.h b/strings/base_extern.h
index fa9906f09..d78b9c3f1 100644
--- a/strings/base_extern.h
+++ b/strings/base_extern.h
@@ -2,6 +2,7 @@
 __declspec(selectany) int32_t(__stdcall* winrt_to_hresult_handler)(void* address) noexcept {};
 __declspec(selectany) void(__stdcall* winrt_suspend_handler)(void const* token) noexcept {};
 __declspec(selectany) void(__stdcall* winrt_resume_handler)(void const* token) noexcept {};
+__declspec(selectany) int32_t(__stdcall* winrt_activation_handler)(void* classId, winrt::guid const& iid, void** factory) noexcept {};
 
 extern "C"
 {
diff --git a/test/test/custom_activation.cpp b/test/test/custom_activation.cpp
new file mode 100644
index 000000000..d3e309461
--- /dev/null
+++ b/test/test/custom_activation.cpp
@@ -0,0 +1,52 @@
+#include "winrt/Windows.Foundation.Numerics.h"
+#include "catch.hpp"
+
+using namespace winrt;
+using namespace Windows::Foundation;
+
+namespace
+{
+    struct custom_factory : implements<custom_factory, IUriRuntimeClassFactory>
+    {
+        inline static Uri mock_uri{ nullptr };
+
+        Uri CreateUri(hstring const& value) const
+        {
+            REQUIRE(value == L"http://ignored.com");
+            return mock_uri;
+        }
+
+        Uri CreateWithRelativeUri(hstring const&, hstring const&) const
+        {
+            throw hresult_not_implemented();
+        }
+    };
+
+    int32_t __stdcall handler(void* classId, winrt::guid const& iid, void** factory) noexcept
+    {
+        bool expected = reinterpret_cast<hstring const&>(classId) == L"Windows.Foundation.Uri";
+        REQUIRE(expected);
+        REQUIRE(iid == guid_of<IUriRuntimeClassFactory>());
+
+        *factory = detach_abi(make<custom_factory>());
+        return 0;
+    }
+}
+
+TEST_CASE("custom_activation")
+{
+    custom_factory::mock_uri = Uri(L"http://actual.com");
+    clear_factory_cache();
+
+    // Set up global handler
+    REQUIRE(!winrt_activation_handler);
+    winrt_activation_handler = handler;
+
+    // Windows.Foundation.Uri activation factory now returns mock object
+    auto uri = Uri(L"http://ignored.com");
+    REQUIRE(uri.Domain() == L"actual.com");
+
+    // Remove global handler
+    winrt_activation_handler = nullptr;
+    clear_factory_cache();
+}
diff --git a/test/test/test.vcxproj b/test/test/test.vcxproj
index 604aff066..41419ebae 100644
--- a/test/test/test.vcxproj
+++ b/test/test/test.vcxproj
@@ -315,6 +315,16 @@
       <PrecompiledHeader Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">NotUsing</PrecompiledHeader>
       <PrecompiledHeader Condition="'$(Configuration)|$(Platform)'=='Release|x64'">NotUsing</PrecompiledHeader>
     </ClCompile>
+    <ClCompile Include="custom_activation.cpp">
+      <PrecompiledHeader Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">NotUsing</PrecompiledHeader>
+      <PrecompiledHeader Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">NotUsing</PrecompiledHeader>
+      <PrecompiledHeader Condition="'$(Configuration)|$(Platform)'=='Debug|ARM64'">NotUsing</PrecompiledHeader>
+      <PrecompiledHeader Condition="'$(Configuration)|$(Platform)'=='Release|ARM64'">NotUsing</PrecompiledHeader>
+      <PrecompiledHeader Condition="'$(Configuration)|$(Platform)'=='Debug|ARM'">NotUsing</PrecompiledHeader>
+      <PrecompiledHeader Condition="'$(Configuration)|$(Platform)'=='Release|ARM'">NotUsing</PrecompiledHeader>
+      <PrecompiledHeader Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">NotUsing</PrecompiledHeader>
+      <PrecompiledHeader Condition="'$(Configuration)|$(Platform)'=='Release|x64'">NotUsing</PrecompiledHeader>
+    </ClCompile>
     <ClCompile Include="custom_error.cpp" />
     <ClCompile Include="delegate.cpp" />
     <ClCompile Include="delegates.cpp" />