Fix Unable to perform a database vacuum: out of memory when exiting (#…

…2398)

* Due to many poor Internet sources of how to use this application, may folk still do not add --synchronize or --monitor switches because their documentation source fails to detail this. When this is the case, the itemdb does not get fully initialised, but when we exit, we try and clean up, because we have partially initalised, we cannot perform a vacuum of the database which generates an error. This patch adds a flag for this specific scenario, so that if triggered, we do not try to vacuum the database and not triggering a false error.

src/main.d

@@ -57,6 +57,7 @@ int main(string[] args)
 	bool displaySyncOptions = false;
 	bool cleanupLocalFilesGlobal = false;
 	bool synchronizeConfigured = false;
+	bool invalidSyncExit = false;
 
 	// start and finish messages
 	string startMessage = "Starting a sync with OneDrive";
@@ -85,7 +86,9 @@ int main(string[] args)
 		// was itemDb initialised?
 		if (itemDb !is null) {
 			// Make sure the .wal file is incorporated into the main db before we exit
-			itemDb.performVacuum();
+			if(!invalidSyncExit) {
+				itemDb.performVacuum();
+			}
 			destroy(itemDb);
 		}
 		// cleanup any dry-run data
@@ -116,7 +119,9 @@ int main(string[] args)
 		// was itemDb initialised?
 		if (itemDb !is null) {
 			// Make sure the .wal file is incorporated into the main db before we exit
-			itemDb.performVacuum();
+			if(!invalidSyncExit) {
+				itemDb.performVacuum();
+			}
 			destroy(itemDb);
 		}
 		// cleanup any dry-run data
@@ -985,6 +990,7 @@ int main(string[] args)
 			log.log("\n--synchronize or --monitor switches missing from your command line input. Please add one (not both) of these switches to your command line or use 'onedrive --help' for further assistance.\n");
 			log.log("No OneDrive sync will be performed without one of these two arguments being present.\n");
 			// Use exit scopes to shutdown API
+			invalidSyncExit = true;
 			return EXIT_FAILURE;
 		}
 	}