sync: Improve logging when connection restored, avoid retries. (#1408)

* sync: Improve logging when connection restored, avoid retries.

Don't retry requests if the error is that the machine is offline

Source/santasyncservice/SNTSyncManager.m

@@ -257,8 +257,8 @@ - (SNTSyncStatusType)preflightOnly:(BOOL)preflightOnly {
     return [self eventUploadWithSyncState:syncState];
   }
 
-  LOGE(@"Preflight failed, will try again once %@ is reachable",
-       [[SNTConfigurator configurator] syncBaseURL].absoluteString);
+  SLOGE(@"Preflight failed, will try again once %@ is reachable",
+        [[SNTConfigurator configurator] syncBaseURL].absoluteString);
   [self startReachability];
   return SNTSyncStatusTypePreflightFailed;
 }
@@ -386,6 +386,7 @@ - (SNTSyncState *)createSyncStateWithStatus:(SNTSyncStatusType *)status {
 - (void)setReachable:(BOOL)reachable {
   _reachable = reachable;
   if (reachable) {
+    LOGD(@"Internet connection has been restored, triggering a new sync.");
     [self stopReachability];
     [self sync];
   }

Source/santasyncservice/SNTSyncStage.mm

@@ -14,6 +14,7 @@
 
 #import "Source/santasyncservice/SNTSyncStage.h"
 
+#include <Foundation/Foundation.h>
 #import <MOLXPCConnection/MOLXPCConnection.h>
 
 #import "Source/common/SNTCommonEnums.h"
@@ -176,6 +177,11 @@ - (NSData *)dataFromRequest:(NSURLRequest *)request
     data = [self performRequest:request timeout:timeout response:&response error:&requestError];
     if (response.statusCode == 200) break;
 
+    // If the original request failed because of a "No network" error, break out of the loop,
+    // subsequent retries are pointless and the entire sync will be retried once a connection
+    // is established.
+    if (requestError.code == NSURLErrorNotConnectedToInternet) break;
+
     // If the original request failed because of an auth error, attempt to get a new XSRF token and
     // try again. Unfortunately some servers cause NSURLSession to return 'client cert required' or
     // 'could not parse response' when a 403 occurs and SSL cert auth is enabled.