Port FieldTransform to C++ (#1033)

* port FieldMask to C++

* address changes

* address changes

* fix test

* address change

* Port transform operations (FSTTransformOperation, FSTServerTimestampTransform) to C++

* address changes

* address changes

* address changes

* implement `FieldTransform` in C++

* port `FieldTransform`

* make `fieldTransforms` shared inside `context`

* address changes

* fix lint

* address changes

2 files changed, 40 insertions, 0 deletions

diff --git a/Firestore/core/test/firebase/firestore/model/CMakeLists.txt b/Firestore/core/test/firebase/firestore/model/CMakeLists.txt
index 5e494f1..3bac89d 100644
--- a/Firestore/core/test/firebase/firestore/model/CMakeLists.txt
+++ b/Firestore/core/test/firebase/firestore/model/CMakeLists.txt
@@ -20,6 +20,7 @@ cc_test(
     document_test.cc
     field_mask_test.cc
     field_path_test.cc
+    field_transform_test.cc
     field_value_test.cc
     maybe_document_test.cc
     no_document_test.cc
diff --git a/Firestore/core/test/firebase/firestore/model/field_transform_test.cc b/Firestore/core/test/firebase/firestore/model/field_transform_test.cc
new file mode 100644
index 0000000..b66aeef
--- /dev/null
+++ b/Firestore/core/test/firebase/firestore/model/field_transform_test.cc
@@ -0,0 +1,39 @@
+/*
+ * Copyright 2018 Google
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "Firestore/core/src/firebase/firestore/model/field_transform.h"
+#include "Firestore/core/src/firebase/firestore/model/transform_operations.h"
+#include "Firestore/core/test/firebase/firestore/testutil/testutil.h"
+
+#include "absl/memory/memory.h"
+#include "gtest/gtest.h"
+
+namespace firebase {
+namespace firestore {
+namespace model {
+
+TEST(FieldTransform, Getter) {
+  FieldTransform transform(testutil::Field("foo"),
+                           absl::make_unique<ServerTimestampTransform>(
+                               ServerTimestampTransform::Get()));
+
+  EXPECT_EQ(testutil::Field("foo"), transform.path());
+  EXPECT_EQ(ServerTimestampTransform::Get(), transform.transformation());
+}
+
+}  // namespace model
+}  // namespace firestore
+}  // namespace firebase