From f8dd62ca438309cce4f933bca6b5346fd28d68d8 Mon Sep 17 00:00:00 2001
From: nielsandriesse <andriesseniels@gmail.com>
Date: Fri, 31 Jul 2020 09:45:16 +1000
Subject: [PATCH] Clean

---
 Signal/src/Loki/View Controllers/HomeVC.swift | 29 +++++++------------
 Signal/src/util/MainAppContext.m              |  1 -
 2 files changed, 10 insertions(+), 20 deletions(-)

diff --git a/Signal/src/Loki/View Controllers/HomeVC.swift b/Signal/src/Loki/View Controllers/HomeVC.swift
index eec8fefc7..dfa9c5553 100644
--- a/Signal/src/Loki/View Controllers/HomeVC.swift	
+++ b/Signal/src/Loki/View Controllers/HomeVC.swift	
@@ -216,21 +216,17 @@ final class HomeVC : BaseVC, UITableViewDataSource, UITableViewDelegate, UIScrol
         isObservingDatabase = isViewVisible && CurrentAppContext().isAppForegroundAndActive()
     }
     
-    private func updateYDBThreadMapping() {
+    private func reload() {
+        AssertIsOnMainThread()
         uiDatabaseConnection.beginLongLivedReadTransaction()
         uiDatabaseConnection.read { transaction in
             self.threads.update(with: transaction)
         }
-    }
-    
-    private func reload() {
-        AssertIsOnMainThread()
-        updateYDBThreadMapping()
         threadViewModelCache.removeAll()
         tableView.reloadData()
         emptyStateView.isHidden = (threadCount != 0)
     }
-    
+
     @objc private func handleYapDatabaseModifiedNotification(_ notification: Notification) {
         AssertIsOnMainThread()
         guard isObservingDatabase else { return }
@@ -243,17 +239,13 @@ final class HomeVC : BaseVC, UITableViewDataSource, UITableViewDelegate, UIScrol
             }
             return
         }
-        // Guard for changes made in Notification Service Extension
-        // Crashes may happen if there is some modification in NSE
-        // The YapDBModificationNotification cannot cross process
-        // So the thread mapping won't update itself if DB modification happened in other process like NSE
-        // With these code we can sync the mapping before asking for changes from YapDB
-        if (notifications.count > 0) {
-            if let firstChangeset = notifications[0].userInfo {
-                let firstSnapshot = firstChangeset[YapDatabaseSnapshotKey] as! UInt64
-                if (self.threads.snapshotOfLastUpdate != firstSnapshot - 1) {
-                    reload()
-                    return
+        // If changes were made in a different process (e.g. the Notification Service Extension) the thread mapping can be out of date
+        // at this point, causing the app to crash. The code below prevents that by force syncing the database before proceeding.
+        if notifications.count > 0 {
+            if let firstChangeSet = notifications[0].userInfo {
+                let firstSnapshot = firstChangeSet[YapDatabaseSnapshotKey] as! UInt64
+                if threads.snapshotOfLastUpdate != firstSnapshot - 1 {
+                    return reload()
                 }
             }
         }
@@ -283,7 +275,6 @@ final class HomeVC : BaseVC, UITableViewDataSource, UITableViewDelegate, UIScrol
     
     @objc private func handleApplicationDidBecomeActiveNotification(_ notification: Notification) {
         updateIsObservingDatabase()
-        updateYDBThreadMapping()
     }
     
     @objc private func handleApplicationWillResignActiveNotification(_ notification: Notification) {
diff --git a/Signal/src/util/MainAppContext.m b/Signal/src/util/MainAppContext.m
index e367efa31..9790ae493 100644
--- a/Signal/src/util/MainAppContext.m
+++ b/Signal/src/util/MainAppContext.m
@@ -157,7 +157,6 @@ NSString *const ReportedApplicationStateDidChangeNotification = @"ReportedApplic
 
 - (BOOL)isMainAppAndActive
 {
-    if (![NSThread isMainThread]) { return NO; }
     return [UIApplication sharedApplication].applicationState == UIApplicationStateActive;
 }