Firestore project: Import of API interfaces. (#1337)

- 198063502 Address comment upstream. by zxu <zxu>
  - 197942352 Fix style upstream and fix destination depot in copybara. by zxu <zxu>
  - 197925542 Fix headers with change from GitHub, see the current diff... by zxu <zxu>
  - 197922012 Implement ListenerRegistration::Remove(). by zxu <zxu>
  - 197713382 Implement more on listener class and implement ListenerRe... by zxu <zxu>
  - 196551381 Implement more on listener class and implement the Docume... by zxu <zxu>
  - 196276752 Implement the SnapshotMetadata with inline methods and (n... by zxu <zxu>
  - 195841793 Implement the wrapper class for callback (EventListener). by zxu <zxu>
  - 194112388 Add Android-Wrapper for DocumentReference's non-callback ... by zxu <zxu>
  - 192445183 Add Android-Wrapper for Firestore's remaining methods. by zxu <zxu>
  - 190986604 Manually import the public portion of by mcg <mcg>
  - 189013767 Add Android-Wrapper for Firestore's method that does not ... by zxu <zxu>
  - 188809445 Import of firebase-ios-sdk from Github. by mcg <mcg>
  - 187049498 Import of firebase-ios-sdk from Github. by mcg <mcg>
  - 184568931 Import of firebase-ios-sdk from Github. by mcg <mcg>

ORIGINAL_AUTHOR=Firebase <firebase-noreply>
PiperOrigin-RevId: 198063502

1 files changed, 38 insertions, 0 deletions

diff --git a/Firestore/core/include/firebase/firestore/document_snapshot.h b/Firestore/core/include/firebase/firestore/document_snapshot.h
new file mode 100644
index 0000000..3be72b5
--- /dev/null
+++ b/Firestore/core/include/firebase/firestore/document_snapshot.h
@@ -0,0 +1,38 @@
+/*
+ * 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.
+ */
+
+#ifndef FIRESTORE_CORE_INCLUDE_FIREBASE_FIRESTORE_DOCUMENT_SNAPSHOT_H_
+#define FIRESTORE_CORE_INCLUDE_FIREBASE_FIRESTORE_DOCUMENT_SNAPSHOT_H_
+
+namespace firebase {
+namespace firestore {
+
+/**
+ * A DocumentSnapshot contains data read from a document in your Firestore
+ * database. The data can be extracted with the data() method or by using
+ * FooValue() to access a specific field, where Foo is the type of that field.
+ *
+ * For a DocumentSnapshot that points to a non-existing document, any data
+ * access will cause a failed assertion. You can use the exists() method to
+ * explicitly verify a documents existence.
+ */
+// TODO(zxu123): add more methods to complete the class and make it useful.
+class DocumentSnapshot {};
+
+}  // namespace firestore
+}  // namespace firebase
+
+#endif  // FIRESTORE_CORE_INCLUDE_FIREBASE_FIRESTORE_DOCUMENT_SNAPSHOT_H_