1 files changed, 122 insertions, 0 deletions
diff --git a/Firestore/Source/Core/FSTTimestamp.m b/Firestore/Source/Core/FSTTimestamp.m
new file mode 100644
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+++ b/Firestore/Source/Core/FSTTimestamp.m
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+/*
+ * 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 "FSTTimestamp.h"
+
+#import "FSTAssert.h"
+#import "FSTComparison.h"
+
+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 = FSTCompareInt64s(self.seconds, other.seconds);
+  if (result != NSOrderedSame) {
+    return result;
+  }
+  return FSTCompareInt32s(self.nanos, other.nanos);
+}
+
+@end
+
+NS_ASSUME_NONNULL_END