Timestamp helper fix, Duration helper cleanup.

- The Timestamp proto does not allow for negative nanos fields, so the seconds
  must be shifted and a positive nanos then applied.
- Tweak the helpers on Duration to make it clear there is no "base" time
  involved.
- Update the unittests for duration and timestamp to cover positive and
  negative NSTimeIntervals and what their impact is on the protos.

1 files changed, 14 insertions, 3 deletions

diff --git a/objectivec/GPBWellKnownTypes.h b/objectivec/GPBWellKnownTypes.h
index 90d96c6f..04df4178 100644
--- a/objectivec/GPBWellKnownTypes.h
+++ b/objectivec/GPBWellKnownTypes.h
@@ -112,16 +112,27 @@ typedef NS_ENUM(NSInteger, GPBWellKnownTypesErrorCode) {
  * @note: Not all second/nanos combinations can be represented in a
  * NSTimeInterval, so getting this could be a lossy transform.
  **/
-@property(nonatomic, readwrite) NSTimeInterval timeIntervalSince1970;
+@property(nonatomic, readwrite) NSTimeInterval timeInterval;
 
 /**
  * Initializes a GPBDuration with the given NSTimeInterval.
  *
- * @param timeIntervalSince1970 Time interval to configure the GPBDuration with.
+ * @param timeInterval Time interval to configure the GPBDuration with.
  *
  * @return A newly initialized GPBDuration.
  **/
-- (instancetype)initWithTimeIntervalSince1970:(NSTimeInterval)timeIntervalSince1970;
+- (instancetype)initWithTimeInterval:(NSTimeInterval)timeInterval;
+
+// These next two methods are deprecated because GBPDuration has no need of a
+// "base" time. The older methods were about symmetry with GBPTimestamp, but
+// the unix epoch usage is too confusing.
+
+/** Deprecated, use timeInterval instead. */
+@property(nonatomic, readwrite) NSTimeInterval timeIntervalSince1970
+    __attribute__((deprecated("Use timeInterval")));
+/** Deprecated, use initWithTimeInterval: instead. */
+- (instancetype)initWithTimeIntervalSince1970:(NSTimeInterval)timeIntervalSince1970
+    __attribute__((deprecated("Use initWithTimeInterval:")));
 
 @end