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).

4 files changed, 7 insertions, 204 deletions

diff --git a/Firestore/Source/Core/FSTSnapshotVersion.h b/Firestore/Source/Core/FSTSnapshotVersion.h
index b72e4a2..8649d40 100644
--- a/Firestore/Source/Core/FSTSnapshotVersion.h
+++ b/Firestore/Source/Core/FSTSnapshotVersion.h
@@ -18,7 +18,7 @@
 
 NS_ASSUME_NONNULL_BEGIN
 
-@class FSTTimestamp;
+@class FIRTimestamp;
 
 /**
  * A version of a document in Firestore. This corresponds to the version timestamp, such as
@@ -30,13 +30,13 @@ NS_ASSUME_NONNULL_BEGIN
 + (instancetype)noVersion;
 
 /** Creates a new version representing the given timestamp. */
-+ (instancetype)versionWithTimestamp:(FSTTimestamp *)timestamp;
++ (instancetype)versionWithTimestamp:(FIRTimestamp *)timestamp;
 
 - (instancetype)init NS_UNAVAILABLE;
 
 - (NSComparisonResult)compare:(FSTSnapshotVersion *)other;
 
-@property(nonatomic, strong, readonly) FSTTimestamp *timestamp;
+@property(nonatomic, strong, readonly) FIRTimestamp *timestamp;
 
 @end
 
diff --git a/Firestore/Source/Core/FSTSnapshotVersion.mm b/Firestore/Source/Core/FSTSnapshotVersion.mm
index 980ae52..58b2be4 100644
--- a/Firestore/Source/Core/FSTSnapshotVersion.mm
+++ b/Firestore/Source/Core/FSTSnapshotVersion.mm
@@ -16,7 +16,7 @@
 
 #import "Firestore/Source/Core/FSTSnapshotVersion.h"
 
-#import "Firestore/Source/Core/FSTTimestamp.h"
+#import "FIRTimestamp.h"
 
 NS_ASSUME_NONNULL_BEGIN
 
@@ -26,17 +26,17 @@ NS_ASSUME_NONNULL_BEGIN
   static FSTSnapshotVersion *min;
   static dispatch_once_t onceToken;
   dispatch_once(&onceToken, ^{
-    FSTTimestamp *timestamp = [[FSTTimestamp alloc] initWithSeconds:0 nanos:0];
+    FIRTimestamp *timestamp = [[FIRTimestamp alloc] initWithSeconds:0 nanoseconds:0];
     min = [FSTSnapshotVersion versionWithTimestamp:timestamp];
   });
   return min;
 }
 
-+ (instancetype)versionWithTimestamp:(FSTTimestamp *)timestamp {
++ (instancetype)versionWithTimestamp:(FIRTimestamp *)timestamp {
   return [[FSTSnapshotVersion alloc] initWithTimestamp:timestamp];
 }
 
-- (instancetype)initWithTimestamp:(FSTTimestamp *)timestamp {
+- (instancetype)initWithTimestamp:(FIRTimestamp *)timestamp {
   self = [super init];
   if (self) {
     _timestamp = timestamp;
diff --git a/Firestore/Source/Core/FSTTimestamp.h b/Firestore/Source/Core/FSTTimestamp.h
deleted file mode 100644
index f86779d..0000000
--- a/Firestore/Source/Core/FSTTimestamp.h
+++ /dev/null
@@ -1,72 +0,0 @@
-/*
- * Copyright 2017 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
-
-/**
- * An FSTTimestamp represents an absolute time from the backend at up to nanosecond precision.
- * An FSTTimestamp is represented in terms of UTC and does not have an associated timezone.
- */
-@interface FSTTimestamp : NSObject <NSCopying>
-
-- (instancetype)init NS_UNAVAILABLE;
-
-/**
- * Creates a new timestamp.
- *
- * @param seconds the number of seconds since epoch.
- * @param nanos the number of nanoseconds after the seconds.
- */
-- (instancetype)initWithSeconds:(int64_t)seconds nanos:(int32_t)nanos NS_DESIGNATED_INITIALIZER;
-
-/** Creates a new timestamp with the current date / time. */
-+ (instancetype)timestamp;
-
-/** Creates a new timestamp from the given date. */
-+ (instancetype)timestampWithDate:(NSDate *)date;
-
-/** Returns a new NSDate corresponding to this timestamp. This may lose precision. */
-- (NSDate *)approximateDateValue;
-
-/**
- * Converts the given date to a 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;
-
-- (NSComparisonResult)compare:(FSTTimestamp *)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 nanos;
-
-@end
-
-NS_ASSUME_NONNULL_END
diff --git a/Firestore/Source/Core/FSTTimestamp.mm b/Firestore/Source/Core/FSTTimestamp.mm
deleted file mode 100644
index d2b492a..0000000
--- a/Firestore/Source/Core/FSTTimestamp.mm
+++ /dev/null
@@ -1,125 +0,0 @@
-/*
- * Copyright 2017 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 "Firestore/Source/Core/FSTTimestamp.h"
-
-#include "Firestore/core/src/firebase/firestore/util/comparison.h"
-
-#import "Firestore/Source/Util/FSTAssert.h"
-
-using firebase::firestore::util::WrapCompare;
-
-NS_ASSUME_NONNULL_BEGIN
-
-static const int kNanosPerSecond = 1000000000;
-
-@implementation FSTTimestamp
-
-#pragma mark - Constructors
-
-+ (instancetype)timestamp {
-  return [FSTTimestamp timestampWithDate:[NSDate date]];
-}
-
-+ (instancetype)timestampWithDate:(NSDate *)date {
-  double secondsDouble;
-  double fraction = modf(date.timeIntervalSince1970, &secondsDouble);
-  // GCP Timestamps always have non-negative nanos.
-  if (fraction < 0) {
-    fraction += 1.0;
-    secondsDouble -= 1.0;
-  }
-  int64_t seconds = (int64_t)secondsDouble;
-  int32_t nanos = (int32_t)(fraction * kNanosPerSecond);
-  return [[FSTTimestamp alloc] initWithSeconds:seconds nanos:nanos];
-}
-
-- (instancetype)initWithSeconds:(int64_t)seconds nanos:(int32_t)nanos {
-  self = [super init];
-  if (self) {
-    FSTAssert(nanos >= 0, @"timestamp nanoseconds out of range: %d", nanos);
-    FSTAssert(nanos < 1e9, @"timestamp nanoseconds out of range: %d", nanos);
-    // Midnight at the beginning of 1/1/1 is the earliest timestamp Firestore supports.
-    FSTAssert(seconds >= -62135596800L, @"timestamp seconds out of range: %lld", seconds);
-    // This will break in the year 10,000.
-    FSTAssert(seconds < 253402300800L, @"timestamp seconds out of range: %lld", seconds);
-
-    _seconds = seconds;
-    _nanos = nanos;
-  }
-  return self;
-}
-
-#pragma mark - NSObject methods
-
-- (BOOL)isEqual:(id)object {
-  if (self == object) {
-    return YES;
-  }
-  if (![object isKindOfClass:[FSTTimestamp class]]) {
-    return NO;
-  }
-  return [self isEqualToTimestamp:(FSTTimestamp *)object];
-}
-
-- (NSUInteger)hash {
-  return (NSUInteger)((self.seconds >> 32) ^ self.seconds ^ self.nanos);
-}
-
-- (NSString *)description {
-  return [NSString
-      stringWithFormat:@"<FSTTimestamp: seconds=%lld nanos=%d>", self.seconds, self.nanos];
-}
-
-/** Implements NSCopying without actually copying because timestamps are immutable. */
-- (id)copyWithZone:(NSZone *_Nullable)zone {
-  return self;
-}
-
-#pragma mark - Public methods
-
-- (NSDate *)approximateDateValue {
-  NSTimeInterval interval = (NSTimeInterval)self.seconds + ((NSTimeInterval)self.nanos) / 1e9;
-  return [NSDate dateWithTimeIntervalSince1970:interval];
-}
-
-- (BOOL)isEqualToTimestamp:(FSTTimestamp *)other {
-  return [self compare:other] == NSOrderedSame;
-}
-
-- (NSString *)ISO8601String {
-  NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
-  formatter.dateFormat = @"yyyy-MM-dd'T'HH:mm:ss";
-  formatter.timeZone = [NSTimeZone timeZoneWithName:@"UTC"];
-  NSDate *secondsDate = [NSDate dateWithTimeIntervalSince1970:self.seconds];
-  NSString *secondsString = [formatter stringFromDate:secondsDate];
-  FSTAssert(secondsString.length == 19, @"Invalid ISO string: %@", secondsString);
-
-  NSString *nanosString = [NSString stringWithFormat:@"%09d", self.nanos];
-  return [NSString stringWithFormat:@"%@.%@Z", secondsString, nanosString];
-}
-
-- (NSComparisonResult)compare:(FSTTimestamp *)other {
-  NSComparisonResult result = WrapCompare<int64_t>(self.seconds, other.seconds);
-  if (result != NSOrderedSame) {
-    return result;
-  }
-  return WrapCompare<int32_t>(self.nanos, other.nanos);
-}
-
-@end
-
-NS_ASSUME_NONNULL_END