From 471a30ca3dbb20186494af28ca5f5052150c301e Mon Sep 17 00:00:00 2001
From: Thomas Denney <me@thomasdenney.co.uk>
Date: Thu, 15 Sep 2016 09:24:09 +0100
Subject: [PATCH] Minimise memory usage in Mac app directory watcher

---
 clients/macuploader/Microbit Uploader/DirectoryWatcher.m | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/clients/macuploader/Microbit Uploader/DirectoryWatcher.m b/clients/macuploader/Microbit Uploader/DirectoryWatcher.m
index 66290d67..e33fff81 100644
--- a/clients/macuploader/Microbit Uploader/DirectoryWatcher.m	
+++ b/clients/macuploader/Microbit Uploader/DirectoryWatcher.m	
@@ -55,14 +55,16 @@ void callback(ConstFSEventStreamRef streamRef, void * info, size_t numEvents, vo
 
 - (void)rescanPathWithEvents:(BOOL)sendEvents {
     NSArray<NSString*>* downloadFiles = [[NSFileManager defaultManager] contentsOfDirectoryAtPath:self.path error:nil];
+    NSMutableSet<NSString*>* fullSet = [NSMutableSet new];
     for (NSString * file in downloadFiles) {
+        [fullSet addObject:file];
         if (![self.knownFiles containsObject:file]) {
             if (sendEvents) {
                 [self.delegate watcher:self observedNewFileAtPath:file];
             }
-            [self.knownFiles addObject:file];
         }
     }
+    self.knownFiles = fullSet;
 }
 
 @end