Stop lazy attachment restore during backup import.

Signal/src/util/Backup/OWSBackup.h

@@ -42,7 +42,7 @@ NSError *OWSBackupErrorWithDescription(NSString *description);
 
 #pragma mark - Backup Export
 
-@property (nonatomic, readonly) OWSBackupState backupExportState;
+@property (atomic, readonly) OWSBackupState backupExportState;
 
 // If a "backup export" is in progress (see backupExportState),
 // backupExportDescription _might_ contain a string that describes
@@ -65,7 +65,7 @@ NSError *OWSBackupErrorWithDescription(NSString *description);
 
 #pragma mark - Backup Import
 
-@property (nonatomic, readonly) OWSBackupState backupImportState;
+@property (atomic, readonly) OWSBackupState backupImportState;
 
 // If a "backup import" is in progress (see backupImportState),
 // backupImportDescription _might_ contain a string that describes

Signal/src/util/Backup/OWSBackup.m

@@ -93,6 +93,9 @@ NSError *OWSBackupErrorWithDescription(NSString *description)
 @property (nonatomic, nullable) NSString *backupImportDescription;
 @property (nonatomic, nullable) NSNumber *backupImportProgress;
 
+@property (atomic) OWSBackupState backupExportState;
+@property (atomic) OWSBackupState backupImportState;
+
 @end
 
 #pragma mark -
@@ -116,8 +119,8 @@ NSError *OWSBackupErrorWithDescription(NSString *description)
         return self;
     }
 
-    _backupExportState = OWSBackupState_Idle;
-    _backupImportState = OWSBackupState_Idle;
+    self.backupExportState = OWSBackupState_Idle;
+    self.backupImportState = OWSBackupState_Idle;
 
     OWSSingletonAssert();
 
@@ -219,7 +222,7 @@ NSError *OWSBackupErrorWithDescription(NSString *description)
     [self.backupImportJob cancel];
     self.backupImportJob = nil;
 
-    _backupExportState = OWSBackupState_InProgress;
+    self.backupExportState = OWSBackupState_InProgress;
 
     self.backupExportJob = [[OWSBackupExportJob alloc] initWithDelegate:self recipientId:recipientId];
     [self.backupExportJob start];
@@ -402,8 +405,8 @@ NSError *OWSBackupErrorWithDescription(NSString *description)
         }
     }
 
-    BOOL stateDidChange = _backupExportState != backupExportState;
-    _backupExportState = backupExportState;
+    BOOL stateDidChange = self.backupExportState != backupExportState;
+    self.backupExportState = backupExportState;
     if (stateDidChange) {
         [self postDidChangeNotification];
     }
@@ -526,7 +529,7 @@ NSError *OWSBackupErrorWithDescription(NSString *description)
     [self.backupImportJob cancel];
     self.backupImportJob = nil;
 
-    _backupImportState = OWSBackupState_InProgress;
+    self.backupImportState = OWSBackupState_InProgress;
 
     self.backupImportJob = [[OWSBackupImportJob alloc] initWithDelegate:self recipientId:recipientId];
     [self.backupImportJob start];
@@ -539,7 +542,7 @@ NSError *OWSBackupErrorWithDescription(NSString *description)
     [self.backupImportJob cancel];
     self.backupImportJob = nil;
 
-    _backupImportState = OWSBackupState_Idle;
+    self.backupImportState = OWSBackupState_Idle;
 
     [self postDidChangeNotification];
 }
@@ -589,7 +592,7 @@ NSError *OWSBackupErrorWithDescription(NSString *description)
     if (self.backupImportJob == backupJob) {
         self.backupImportJob = nil;
 
-        _backupImportState = OWSBackupState_Succeeded;
+        self.backupImportState = OWSBackupState_Succeeded;
     } else if (self.backupExportJob == backupJob) {
         self.backupExportJob = nil;
 
@@ -613,7 +616,7 @@ NSError *OWSBackupErrorWithDescription(NSString *description)
     if (self.backupImportJob == backupJob) {
         self.backupImportJob = nil;
 
-        _backupImportState = OWSBackupState_Failed;
+        self.backupImportState = OWSBackupState_Failed;
     } else if (self.backupExportJob == backupJob) {
         self.backupExportJob = nil;
 

Signal/src/util/Backup/OWSBackupLazyRestore.swift

@@ -47,6 +47,12 @@ public class BackupLazyRestore: NSObject {
         NotificationCenter.default.addObserver(forName: .reachabilityChanged, object: nil, queue: nil) { _ in
             self.runIfNecessary()
         }
+        NotificationCenter.default.addObserver(forName: .reachabilityChanged, object: nil, queue: nil) { _ in
+            self.runIfNecessary()
+        }
+        NotificationCenter.default.addObserver(forName: NSNotification.Name(NSNotificationNameBackupStateDidChange), object: nil, queue: nil) { _ in
+            self.runIfNecessary()
+        }
     }
 
     // MARK: -
@@ -71,6 +77,11 @@ public class BackupLazyRestore: NSObject {
         runIfNecessary()
     }
 
+    @objc
+    public func isBackupImportInProgress() -> Bool {
+        return backup.backupImportState == .inProgress
+    }
+
     @objc
     public func runIfNecessary() {
         AssertIsOnMainThread()
@@ -81,6 +92,9 @@ public class BackupLazyRestore: NSObject {
         guard tsAccountManager.isRegisteredAndReady() else {
             return
         }
+        guard !isBackupImportInProgress() else {
+            return
+        }
         guard !isRunning, !isComplete else {
             return
         }
@@ -115,6 +129,12 @@ public class BackupLazyRestore: NSObject {
     }
 
     private func tryToRestoreNextAttachment(attachmentIds: [String], errorCount: UInt, backupIO: OWSBackupIO) {
+        guard !isBackupImportInProgress() else {
+            Logger.verbose("A backup import is in progress; abort.")
+            complete(errorCount: errorCount + 1)
+            return
+        }
+
         var attachmentIdsCopy = attachmentIds
         guard let attachmentId = attachmentIdsCopy.popLast() else {
             // This job is done.