Merge branch 'charlesmchen/contactParsingPerf'

Signal/src/contact/SystemContactsFetcher.swift

@@ -88,8 +88,14 @@ class SystemContactsFetcher: NSObject {
     }
 
     private func updateContacts() {
+        AssertIsOnMainThread()
+
         systemContactsHaveBeenRequestedAtLeastOnce = true
 
+        let contactStore = self.contactStore
+        let allowedContactKeys = self.allowedContactKeys
+
+        DispatchQueue.global().async {
             var systemContacts = [CNContact]()
             do {
                 let contactFetchRequest = CNContactFetchRequest(keysToFetch: allowedContactKeys)
@@ -102,8 +108,11 @@ class SystemContactsFetcher: NSObject {
             }
 
             let contacts = systemContacts.map { Contact(systemContact: $0) }
+            DispatchQueue.main.async {
                 self.delegate?.systemContactsFetcher(self, updatedContacts: contacts)
             }
+        }
+    }
 
     private func startObservingContactChanges() {
         NotificationCenter.default.addObserver(self,

Signal/src/util/OWSContactsSyncing.m

@@ -19,6 +19,8 @@ NSString *const kTSStorageManagerOWSContactsSyncingLastMessageKey =
 
 @interface OWSContactsSyncing ()
 
+@property (nonatomic, readonly) dispatch_queue_t serialQueue;
+
 @property (nonatomic, readonly) OWSContactsManager *contactsManager;
 @property (nonatomic, readonly) OWSMessageSender *messageSender;
 @property (nonatomic) BOOL isRequestInFlight;
@@ -70,6 +72,12 @@ NSString *const kTSStorageManagerOWSContactsSyncingLastMessageKey =
 {
     AssertIsOnMainThread();
 
+    if (!self.serialQueue) {
+        _serialQueue = dispatch_queue_create("org.whispersystems.contacts.syncing", DISPATCH_QUEUE_SERIAL);
+    }
+
+    dispatch_async(self.serialQueue, ^{
+
         if (self.isRequestInFlight) {
             // De-bounce.  It's okay if we ignore some new changes;
             // `sendSyncContactsMessageIfPossible` is called fairly
@@ -103,17 +111,18 @@ NSString *const kTSStorageManagerOWSContactsSyncingLastMessageKey =
                                                      forKey:kTSStorageManagerOWSContactsSyncingLastMessageKey
                                                inCollection:kTSStorageManagerOWSContactsSyncingCollection];
 
-            dispatch_async(dispatch_get_main_queue(), ^{
+                dispatch_async(self.serialQueue, ^{
                     self.isRequestInFlight = NO;
                 });
             }
             failure:^(NSError *error) {
                 DDLogError(@"%@ Failed to send contacts sync message with error: %@", self.tag, error);
 
-            dispatch_async(dispatch_get_main_queue(), ^{
+                dispatch_async(self.serialQueue, ^{
                     self.isRequestInFlight = NO;
                 });
             }];
+    });
 }
 
 - (void)sendSyncContactsMessageIfPossible