port Firestore SnapshotVersion in C++ (#767)

* implement SnapshotVersion and test

1 files changed, 34 insertions, 0 deletions

diff --git a/Firestore/core/src/firebase/firestore/model/snapshot_version.cc b/Firestore/core/src/firebase/firestore/model/snapshot_version.cc
new file mode 100644
index 0000000..114e313
--- /dev/null
+++ b/Firestore/core/src/firebase/firestore/model/snapshot_version.cc
@@ -0,0 +1,34 @@
+/*
+ * 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/snapshot_version.h"
+
+namespace firebase {
+namespace firestore {
+namespace model {
+
+SnapshotVersion::SnapshotVersion(const Timestamp& timestamp)
+    : timestamp_(timestamp) {
+}
+
+const SnapshotVersion& SnapshotVersion::None() {
+  static const SnapshotVersion kNone(Timestamp{});
+  return kNone;
+}
+
+}  // namespace model
+}  // namespace firestore
+}  // namespace firebase