Make FSTTimestamp into a public Firestore class (#698)

- FSTTimestamp is now FIRTimestamp, under Firestore/Source/{Public,API}. This is a temporary solution; eventually, FIRTimestamp is supposed to live somewhere under Firebase;
- move most internal Timestamp methods to the public header (the only exception is ISOString).

1 files changed, 35 insertions, 0 deletions

diff --git a/Firestore/Source/API/FIRTimestamp+Internal.h b/Firestore/Source/API/FIRTimestamp+Internal.h
new file mode 100644
index 0000000..48e38b2
--- /dev/null
+++ b/Firestore/Source/API/FIRTimestamp+Internal.h
@@ -0,0 +1,35 @@
+/*
+ * 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.
+ */
+
+#import "FIRTimestamp.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+/** Internal FIRTimestamp API we don't want exposed in our public header files. */
+@interface FIRTimestamp (Internal)
+
+/**
+ * Converts the given date to an ISO 8601 timestamp string, useful for rendering in JSON.
+ *
+ * ISO 8601 dates times in UTC look like this: "1912-04-14T23:40:00.000000000Z".
+ *
+ * @see http://www.ecma-international.org/ecma-262/6.0/#sec-date-time-string-format
+ */
+- (NSString *)ISO8601String;
+
+@end
+
+NS_ASSUME_NONNULL_END