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).

2 files changed, 83 insertions, 0 deletions

diff --git a/Firestore/Source/Public/FIRTimestamp.h b/Firestore/Source/Public/FIRTimestamp.h
new file mode 100644
index 0000000..d0a77f3
--- /dev/null
+++ b/Firestore/Source/Public/FIRTimestamp.h
@@ -0,0 +1,82 @@
+/*
+ * 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 <Foundation/Foundation.h>
+
+NS_ASSUME_NONNULL_BEGIN
+
+/**
+ * A Timestamp represents a point in time independent of any time zone or calendar, represented as
+ * seconds and fractions of seconds at nanosecond resolution in UTC Epoch time. It is encoded using
+ * the Proleptic Gregorian Calendar which extends the Gregorian calendar backwards to year one. It
+ * is encoded assuming all minutes are 60 seconds long, i.e. leap seconds are "smeared" so that no
+ * leap second table is needed for interpretation. Range is from 0001-01-01T00:00:00Z to
+ * 9999-12-31T23:59:59.999999999Z. By restricting to that range, we ensure that we can convert to
+ * and from  RFC 3339 date strings.
+ *
+ * @see https://github.com/google/protobuf/blob/master/src/google/protobuf/timestamp.proto for the
+ * reference timestamp definition.
+ */
+NS_SWIFT_NAME(Timestamp)
+@interface FIRTimestamp : NSObject <NSCopying>
+
+/** */
+- (instancetype)init NS_UNAVAILABLE;
+
+/**
+ * Creates a new timestamp.
+ *
+ * @param seconds the number of seconds since epoch.
+ * @param nanoseconds the number of nanoseconds after the seconds.
+ */
+- (instancetype)initWithSeconds:(int64_t)seconds
+                    nanoseconds:(int32_t)nanoseconds NS_DESIGNATED_INITIALIZER;
+
+/**
+ * Creates a new timestamp.
+ *
+ * @param seconds the number of seconds since epoch.
+ * @param nanoseconds the number of nanoseconds after the seconds.
+ */
++ (instancetype)timestampWithSeconds:(int64_t)seconds nanoseconds:(int32_t)nanoseconds;
+
+/** Creates a new timestamp from the given date. */
++ (instancetype)timestampWithDate:(NSDate *)date;
+
+/** Creates a new timestamp with the current date / time. */
++ (instancetype)timestamp;
+
+/** Returns a new NSDate corresponding to this timestamp. This may lose precision. */
+- (NSDate *)approximateDateValue;
+
+- (NSComparisonResult)compare:(FIRTimestamp *)other;
+
+/**
+ * Represents seconds of UTC time since Unix epoch 1970-01-01T00:00:00Z.
+ * Must be from 0001-01-01T00:00:00Z to 9999-12-31T23:59:59Z inclusive.
+ */
+@property(nonatomic, assign, readonly) int64_t seconds;
+
+/**
+ * Non-negative fractions of a second at nanosecond resolution. Negative second values with
+ * fractions must still have non-negative nanos values that count forward in time.
+ * Must be from 0 to 999,999,999 inclusive.
+ */
+@property(nonatomic, assign, readonly) int32_t nanoseconds;
+
+@end
+
+NS_ASSUME_NONNULL_END
diff --git a/Firestore/Source/Public/FirebaseFirestore.h b/Firestore/Source/Public/FirebaseFirestore.h
index ff110fd..36f9fb7 100644
--- a/Firestore/Source/Public/FirebaseFirestore.h
+++ b/Firestore/Source/Public/FirebaseFirestore.h
@@ -29,5 +29,6 @@
 #import "FIRQuerySnapshot.h"
 #import "FIRSetOptions.h"
 #import "FIRSnapshotMetadata.h"
+#import "FIRTimestamp.h"
 #import "FIRTransaction.h"
 #import "FIRWriteBatch.h"