Geolocation Accuracy and Cached Location Bug

Summary:There are two issues:

1. When calling startObserving or getCurrentPosition for the first time, _locationManager is not initialized and the accuracy value set in options is lost.

2. When using the cached location _lastLocationEvent, current timestamp retrieved by CFAbsoluteTimeGetCurrent() is from 2001, but the timestamp of the location is from 1970. In addition, the comparison between _lastLocationEvent[@"coords"][@"accuracy"] and options.accuracy is incorrect. Less value indicates more accurate location.
Closes facebook#6198

Differential Revision: D3023786

Pulled By: nicklockwood

fb-gh-sync-id: 869c0e34252470275bf99cf0e5861747247f1158
shipit-source-id: 869c0e34252470275bf99cf0e5861747247f1158

Libraries/Geolocation/RCTLocationObserver.m

@@ -124,7 +124,7 @@ - (dispatch_queue_t)methodQueue
 
 #pragma mark - Private API
 
-- (void)beginLocationUpdates
+- (void)beginLocationUpdatesWithDesiredAccuracy:(CLLocationAccuracy)desiredAccuracy
 {
   if (!_locationManager) {
     _locationManager = [CLLocationManager new];
@@ -143,6 +143,7 @@ - (void)beginLocationUpdates
   }
   */
 
+  _locationManager.desiredAccuracy = desiredAccuracy;
   // Start observing location
   [_locationManager startUpdatingLocation];
 }
@@ -174,8 +175,7 @@ - (void)timeout:(NSTimer *)timer
     _observerOptions.accuracy = MIN(_observerOptions.accuracy, request.options.accuracy);
   }
 
-  _locationManager.desiredAccuracy = _observerOptions.accuracy;
-  [self beginLocationUpdates];
+  [self beginLocationUpdatesWithDesiredAccuracy:_observerOptions.accuracy];
   _observingLocation = YES;
 }
 
@@ -221,8 +221,8 @@ - (void)timeout:(NSTimer *)timer
 
   // Check if previous recorded location exists and is good enough
   if (_lastLocationEvent &&
-      CFAbsoluteTimeGetCurrent() - [RCTConvert NSTimeInterval:_lastLocationEvent[@"timestamp"]] < options.maximumAge &&
-      [_lastLocationEvent[@"coords"][@"accuracy"] doubleValue] >= options.accuracy) {
+      [NSDate date].timeIntervalSince1970 - [RCTConvert NSTimeInterval:_lastLocationEvent[@"timestamp"]] < options.maximumAge &&
+      [_lastLocationEvent[@"coords"][@"accuracy"] doubleValue] <= options.accuracy) {
 
     // Call success block with most recent known location
     successBlock(@[_lastLocationEvent]);
@@ -245,8 +245,11 @@ - (void)timeout:(NSTimer *)timer
   [_pendingRequests addObject:request];
 
   // Configure location manager and begin updating location
-  _locationManager.desiredAccuracy = MIN(_locationManager.desiredAccuracy, options.accuracy);
-  [self beginLocationUpdates];
+  CLLocationAccuracy accuracy = options.accuracy;
+  if (_locationManager) {
+    accuracy = MIN(_locationManager.desiredAccuracy, accuracy);
+  }
+  [self beginLocationUpdatesWithDesiredAccuracy:accuracy];
 }
 
 #pragma mark - CLLocationManagerDelegate
@@ -282,7 +285,7 @@ - (void)locationManager:(CLLocationManager *)manager
   }
   [_pendingRequests removeAllObjects];
 
-  // Stop updating if not not observing
+  // Stop updating if not observing
   if (!_observingLocation) {
     [_locationManager stopUpdatingLocation];
   }