Fixed ReactContext copy/move semantic (#4870)

* Fixed ReactContext copy/move semantic

* Change files

* Fixed formatting

* Test to show how to use a delegate in ReactPropertyBag

change/react-native-windows-2020-05-11-11-06-42-FixReactContext.json

@@ -0,0 +1,8 @@
+{
+  "type": "prerelease",
+  "comment": "Fixed ReactContext copy/move semantic",
+  "packageName": "react-native-windows",
+  "email": "vmorozov@microsoft.com",
+  "dependentChangeType": "patch",
+  "date": "2020-05-11T18:06:42.425Z"
+}

vnext/Microsoft.ReactNative.Cxx.UnitTests/Microsoft.ReactNative.Cxx.UnitTests.vcxproj

@@ -126,6 +126,7 @@
     <ClCompile Include="pch.cpp">
       <PrecompiledHeader>Create</PrecompiledHeader>
     </ClCompile>
+    <ClCompile Include="ReactContextTest.cpp" />
     <ClCompile Include="ReactModuleBuilderMock.cpp" />
     <ClCompile Include="TurboModuleTest.cpp" />
   </ItemGroup>

vnext/Microsoft.ReactNative.Cxx.UnitTests/ReactContextTest.cpp

@@ -0,0 +1,113 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+#include "pch.h"
+#include <ReactContext.h>
+#include "ReactModuleBuilderMock.h"
+
+using namespace winrt::Microsoft::ReactNative;
+
+struct ReactContextStub : implements<ReactContextStub, IReactContext> {
+  IReactPropertyBag Properties() noexcept {
+    VerifyElseCrashSz(false, "Not implemented");
+  }
+
+  void DispatchEvent(
+      Windows::UI::Xaml::FrameworkElement const & /*view*/,
+      hstring const & /*eventName*/,
+      JSValueArgWriter const & /*eventDataArgWriter*/) noexcept {
+    VerifyElseCrashSz(false, "Not implemented");
+  }
+
+  void CallJSFunction(
+      hstring const & /*moduleName*/,
+      hstring const & /*functionName*/,
+      JSValueArgWriter const & /*paramsArgWriter*/) noexcept {
+    VerifyElseCrashSz(false, "Not implemented");
+  }
+
+  void EmitJSEvent(
+      hstring const & /*eventEmitterName*/,
+      hstring const & /*eventName*/,
+      JSValueArgWriter const & /*paramsArgWriter*/) noexcept {
+    VerifyElseCrashSz(false, "Not implemented");
+  }
+};
+
+namespace ReactNativeTests {
+
+TEST_CLASS (ReactContextTest) {
+  TEST_METHOD(Test_ctor_Default) {
+    ReactContext context;
+    TestCheck(!context);
+  }
+
+  TEST_METHOD(Test_ctor_IReactContext) {
+    auto reactContextMock = winrt::make<ReactContextStub>();
+    ReactContext context{reactContextMock};
+    TestCheck(context);
+  }
+
+  TEST_METHOD(Test_ctor_copy) {
+    auto reactContextMock = winrt::make<ReactContextStub>();
+    ReactContext context1{reactContextMock};
+    ReactContext context2{context1};
+    TestCheck(context1);
+    TestCheck(context2);
+    TestCheckEqual(context1, context2);
+  }
+
+  TEST_METHOD(Test_ctor_move) {
+    auto reactContextMock = winrt::make<ReactContextStub>();
+    ReactContext context1{reactContextMock};
+    ReactContext context2{std::move(context1)};
+    TestCheck(!context1);
+    TestCheck(context2);
+  }
+
+  TEST_METHOD(Test_assign_nullptr) {
+    ReactContext context;
+    context = nullptr;
+    TestCheck(!context);
+  }
+
+  TEST_METHOD(Test_assign_copy) {
+    auto reactContextMock = winrt::make<ReactContextStub>();
+    ReactContext context1{reactContextMock};
+    ReactContext context2;
+    context2 = context1;
+    TestCheck(context1);
+    TestCheck(context2);
+    TestCheckEqual(context1, context2);
+  }
+
+  TEST_METHOD(Test_assign_move) {
+    auto reactContextMock = winrt::make<ReactContextStub>();
+    ReactContext context1{reactContextMock};
+    ReactContext context2;
+    context2 = std::move(context1);
+    TestCheck(!context1);
+    TestCheck(context2);
+  }
+
+  TEST_METHOD(Test_compare) {
+    auto reactContextMock1 = winrt::make<ReactContextStub>();
+    auto reactContextMock2 = winrt::make<ReactContextStub>();
+    ReactContext context11{reactContextMock1};
+    ReactContext context12{context11};
+    ReactContext context2{reactContextMock2};
+    ReactContext context3;
+    TestCheck(context11 == context12);
+    TestCheck(context12 == context11);
+    TestCheck(context11 != context2);
+    TestCheck(context11 != context3);
+    TestCheck(context2 != context11);
+    TestCheck(context3 != context11);
+    TestCheck(context3 == nullptr);
+    TestCheck(nullptr == context3);
+    TestCheck(context11 != nullptr);
+    TestCheck(nullptr != context11);
+  }
+};
+
+} // namespace ReactNativeTests

vnext/Microsoft.ReactNative.Cxx/JSValueWriter.h

@@ -5,8 +5,9 @@
 #ifndef MICROSOFT_REACTNATIVE_JSVALUEWRITER
 #define MICROSOFT_REACTNATIVE_JSVALUEWRITER
 
+#include <winrt/Microsoft.ReactNative.h>
+#include "JSValue.h"
 #include "StructInfo.h"
-#include "winrt/Microsoft.ReactNative.h"
 
 namespace winrt::Microsoft::ReactNative {
 

vnext/Microsoft.ReactNative.Cxx/ReactContext.h

@@ -15,6 +15,8 @@ namespace winrt::Microsoft::ReactNative {
 // It wraps up the IReactContext and adds convenience methods for
 // working with C++ types.
 struct ReactContext {
+  ReactContext(std::nullptr_t = nullptr) noexcept {}
+
   ReactContext(IReactContext const &handle) noexcept : m_handle{handle} {}
 
   IReactContext const &Handle() const noexcept {
@@ -68,8 +70,32 @@ struct ReactContext {
     m_handle.DispatchEvent(view, eventName, paramsArgWriter);
   }
 
+  friend bool operator==(ReactContext const &left, ReactContext const &right) noexcept {
+    return left.m_handle == right.m_handle;
+  }
+
+  friend bool operator!=(ReactContext const &left, ReactContext const &right) noexcept {
+    return left.m_handle != right.m_handle;
+  }
+
+  friend bool operator==(ReactContext const &left, std::nullptr_t) noexcept {
+    return !static_cast<bool>(left.m_handle);
+  }
+
+  friend bool operator!=(ReactContext const &left, std::nullptr_t) noexcept {
+    return static_cast<bool>(left.m_handle);
+  }
+
+  friend bool operator==(std::nullptr_t, ReactContext const &right) noexcept {
+    return !static_cast<bool>(right.m_handle);
+  }
+
+  friend bool operator!=(std::nullptr_t, ReactContext const &right) noexcept {
+    return static_cast<bool>(right.m_handle);
+  }
+
  private:
-  const IReactContext m_handle;
+  IReactContext m_handle;
 };
 
 } // namespace winrt::Microsoft::ReactNative

vnext/Microsoft.ReactNative.IntegrationTests/ReactNativeHostTests.cpp

@@ -1,6 +1,8 @@
 #include "pch.h"
 
-#include <winrt/Microsoft.ReactNative.h>
+#include <NativeModules.h>
+
+using namespace React;
 
 namespace ReactNativeIntegrationTests {
 

vnext/Microsoft.ReactNative.IntegrationTests/ReactPropertyBagTests.cpp

@@ -491,7 +491,6 @@ TEST_CLASS (ReactPropertyBagTests) {
   }
 
   TEST_METHOD(PropertyBag_Property_string) {
-    // We only support enums defined in IDL.
     ReactPropertyId<hstring> fooName{L"Foo"};
     ReactPropertyBag pb{ReactPropertyBagHelper::CreatePropertyBag()};
 
@@ -504,6 +503,25 @@ TEST_CLASS (ReactPropertyBagTests) {
     pb.Remove(fooName);
     TestCheck(!pb.Get(fooName));
   }
+
+  TEST_METHOD(PropertyBag_Property_delegate) {
+    ReactPropertyId<ReactCreatePropertyValue> fooName{L"Foo"};
+    ReactPropertyBag pb{ReactPropertyBagHelper::CreatePropertyBag()};
+
+    TestCheck(!pb.Get(fooName));
+    ReactCreatePropertyValue createValue1 = []() { return winrt::box_value(5); };
+    TestCheckEqual(createValue1, *pb.GetOrCreate(fooName, [&createValue1]() { return createValue1; }));
+    TestCheckEqual(createValue1, *pb.Get(fooName));
+    TestCheckEqual(5, winrt::unbox_value<int>((*pb.Get(fooName))()));
+
+    ReactCreatePropertyValue createValue2 = []() { return winrt::box_value(10); };
+    pb.Set(fooName, createValue2);
+    TestCheckEqual(createValue2, *pb.Get(fooName));
+    TestCheckEqual(10, winrt::unbox_value<int>((*pb.Get(fooName))()));
+    TestCheck(createValue1 != *pb.Get(fooName));
+    pb.Remove(fooName);
+    TestCheck(!pb.Get(fooName));
+  }
 };
 
 } // namespace ReactNativeIntegrationTests