Improve Swift concurrency safety

iOS_SDK/OneSignalSDK/OneSignal.xcodeproj/project.pbxproj

@@ -53,6 +53,7 @@
 		03E56DD328405F4A006AA1DA /* OneSignalAppDelegateOverrider.m in Sources */ = {isa = PBXBuildFile; fileRef = 03E56DD228405F4A006AA1DA /* OneSignalAppDelegateOverrider.m */; };
 		16664C4C25DDB195003B8A14 /* NSTimeZoneOverrider.m in Sources */ = {isa = PBXBuildFile; fileRef = 16664C4B25DDB195003B8A14 /* NSTimeZoneOverrider.m */; };
 		37E6B2BB19D9CAF300D0C601 /* UIKit.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 37E6B2BA19D9CAF300D0C601 /* UIKit.framework */; settings = {ATTRIBUTES = (Weak, ); }; };
+		3C05904B2B86BC9E00450D48 /* UnfairLock.swift in Sources */ = {isa = PBXBuildFile; fileRef = 3C05904A2B86BC9E00450D48 /* UnfairLock.swift */; };
 		3C0EF49E28A1DBCB00E5434B /* OSUserInternalImpl.swift in Sources */ = {isa = PBXBuildFile; fileRef = 3C0EF49D28A1DBCB00E5434B /* OSUserInternalImpl.swift */; };
 		3C115165289A259500565C41 /* OneSignalOSCore.docc in Sources */ = {isa = PBXBuildFile; fileRef = 3C115164289A259500565C41 /* OneSignalOSCore.docc */; };
 		3C115171289A259500565C41 /* OneSignalOSCore.h in Headers */ = {isa = PBXBuildFile; fileRef = 3C115163289A259500565C41 /* OneSignalOSCore.h */; settings = {ATTRIBUTES = (Public, ); }; };
@@ -943,6 +944,7 @@
 		1AF75EAD1E8567FD0097B315 /* NSString+OneSignal.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = "NSString+OneSignal.m"; sourceTree = "<group>"; };
 		37747F9319147D6500558FAD /* libOneSignal.a */ = {isa = PBXFileReference; explicitFileType = archive.ar; includeInIndex = 0; path = libOneSignal.a; sourceTree = BUILT_PRODUCTS_DIR; };
 		37E6B2BA19D9CAF300D0C601 /* UIKit.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = UIKit.framework; path = System/Library/Frameworks/UIKit.framework; sourceTree = SDKROOT; };
+		3C05904A2B86BC9E00450D48 /* UnfairLock.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = UnfairLock.swift; sourceTree = "<group>"; };
 		3C0EF49D28A1DBCB00E5434B /* OSUserInternalImpl.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = OSUserInternalImpl.swift; sourceTree = "<group>"; };
 		3C115161289A259500565C41 /* OneSignalOSCore.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = OneSignalOSCore.framework; sourceTree = BUILT_PRODUCTS_DIR; };
 		3C115163289A259500565C41 /* OneSignalOSCore.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = OneSignalOSCore.h; sourceTree = "<group>"; };
@@ -1638,6 +1640,14 @@
 			name = Frameworks;
 			sourceTree = "<group>";
 		};
+		3C0590492B86BC5300450D48 /* Utils */ = {
+			isa = PBXGroup;
+			children = (
+				3C05904A2B86BC9E00450D48 /* UnfairLock.swift */,
+			);
+			path = Utils;
+			sourceTree = "<group>";
+		};
 		3C115162289A259500565C41 /* OneSignalOSCore */ = {
 			isa = PBXGroup;
 			children = (
@@ -1651,6 +1661,7 @@
 			isa = PBXGroup;
 			children = (
 				3C115163289A259500565C41 /* OneSignalOSCore.h */,
+				3C0590492B86BC5300450D48 /* Utils */,
 				3C115188289ADEA300565C41 /* OSModelStore.swift */,
 				3C115186289ADE7700565C41 /* OSModelStoreListener.swift */,
 				3C115184289ADE4F00565C41 /* OSModel.swift */,
@@ -3327,6 +3338,7 @@
 				3C115187289ADE7700565C41 /* OSModelStoreListener.swift in Sources */,
 				3CE5F9E3289D88DC004A156E /* OSModelStoreChangedHandler.swift in Sources */,
 				3C2D8A5928B4C4E300BE41F6 /* OSDelta.swift in Sources */,
+				3C05904B2B86BC9E00450D48 /* UnfairLock.swift in Sources */,
 				3C11518D289AF5E800565C41 /* OSModelChangedHandler.swift in Sources */,
 				3C8E6DF928A6D89E0031E48A /* OSOperationExecutor.swift in Sources */,
 			);

iOS_SDK/OneSignalSDK/OneSignalOSCore/Source/OSOperationRepo.swift

@@ -36,10 +36,13 @@ public class OSOperationRepo: NSObject {
     public static let sharedInstance = OSOperationRepo()
     private var hasCalledStart = false
 
+    // The Operation Repo dispatch queue, serial. This synchronizes access to `deltaQueue` and flushing behavior.
+    private let dispatchQueue = DispatchQueue(label: "OneSignal.OSOperationRepo", target: .global())
+
     // Maps delta names to the interfaces for the operation executors
     var deltasToExecutorMap: [String: OSOperationExecutor] = [:]
     var executors: [OSOperationExecutor] = []
-    var deltaQueue: [OSDelta] = []
+    private var deltaQueue: [OSDelta] = []
 
     // TODO: This could come from a config, plist, method, remote params
     var pollIntervalMilliseconds = Int(POLL_INTERVAL_MS)
@@ -62,7 +65,7 @@ public class OSOperationRepo: NSObject {
         OneSignalLog.onesignalLog(.LL_VERBOSE, message: "OSOperationRepo calling start()")
         // register as user observer
         NotificationCenter.default.addObserver(self,
-                                               selector: #selector(self.flushDeltaQueue),
+                                               selector: #selector(self.addFlushDeltaQueueToDispatchQueue),
                                                name: Notification.Name(OS_ON_USER_WILL_CHANGE),
                                                object: nil)
         // Read the Deltas from cache, if any...
@@ -76,7 +79,7 @@ public class OSOperationRepo: NSObject {
     }
 
     private func pollFlushQueue() {
-        DispatchQueue.global().asyncAfter(deadline: .now() + .milliseconds(pollIntervalMilliseconds)) { [weak self] in
+        self.dispatchQueue.asyncAfter(deadline: .now() + .milliseconds(pollIntervalMilliseconds)) { [weak self] in
             self?.flushDeltaQueue()
             self?.pollFlushQueue()
         }
@@ -101,14 +104,21 @@ public class OSOperationRepo: NSObject {
             return
         }
         start()
-        OneSignalLog.onesignalLog(.LL_VERBOSE, message: "OSOperationRepo enqueueDelta: \(delta)")
-        deltaQueue.append(delta)
+        self.dispatchQueue.async {
+            OneSignalLog.onesignalLog(.LL_VERBOSE, message: "OSOperationRepo enqueueDelta: \(delta)")
+            self.deltaQueue.append(delta)
+            // Persist the deltas (including new delta) to storage
+            OneSignalUserDefaults.initShared().saveCodeableData(forKey: OS_OPERATION_REPO_DELTA_QUEUE_KEY, withValue: self.deltaQueue)
+        }
+    }
 
-        // Persist the deltas (including new delta) to storage
-        OneSignalUserDefaults.initShared().saveCodeableData(forKey: OS_OPERATION_REPO_DELTA_QUEUE_KEY, withValue: self.deltaQueue)
+    @objc public func addFlushDeltaQueueToDispatchQueue(inBackground: Bool = false) {
+        self.dispatchQueue.async {
+            self.flushDeltaQueue(inBackground: inBackground)
+        }
     }
 
-    @objc public func flushDeltaQueue(inBackground: Bool = false) {
+    private func flushDeltaQueue(inBackground: Bool = false) {
         guard !paused else {
             OneSignalLog.onesignalLog(.LL_DEBUG, message: "OSOperationRepo not flushing queue due to being paused")
             return
@@ -122,16 +132,17 @@ public class OSOperationRepo: NSObject {
             OSBackgroundTaskManager.beginBackgroundTask(OPERATION_REPO_BACKGROUND_TASK)
         }
 
-        start()
-        if !deltaQueue.isEmpty {
-            OneSignalLog.onesignalLog(.LL_VERBOSE, message: "OSOperationRepo flushDeltaQueue in background: \(inBackground) with queue: \(deltaQueue)")
+        self.start()
+
+        if !self.deltaQueue.isEmpty {
+            OneSignalLog.onesignalLog(.LL_VERBOSE, message: "OSOperationRepo flushDeltaQueue in background: \(inBackground) with queue: \(self.deltaQueue)")
         }
 
         var index = 0
-        for delta in deltaQueue {
-            if let executor = deltasToExecutorMap[delta.name] {
+        for delta in self.deltaQueue {
+            if let executor = self.deltasToExecutorMap[delta.name] {
                 executor.enqueueDelta(delta)
-                deltaQueue.remove(at: index)
+                self.deltaQueue.remove(at: index)
             } else {
                 // keep in queue if no executor matches, we may not have the executor available yet
                 index += 1
@@ -141,17 +152,16 @@ public class OSOperationRepo: NSObject {
         // Persist the deltas (including removed deltas) to storage after they are divvy'd up to executors.
         OneSignalUserDefaults.initShared().saveCodeableData(forKey: OS_OPERATION_REPO_DELTA_QUEUE_KEY, withValue: self.deltaQueue)
 
-        for executor in executors {
+        for executor in self.executors {
             executor.cacheDeltaQueue()
         }
 
-        for executor in executors {
+        for executor in self.executors {
             executor.processDeltaQueue(inBackground: inBackground)
         }
 
         if inBackground {
             OSBackgroundTaskManager.endBackgroundTask(OPERATION_REPO_BACKGROUND_TASK)
         }
-
     }
 }

iOS_SDK/OneSignalSDK/OneSignalOSCore/Source/Utils/UnfairLock.swift

@@ -0,0 +1,47 @@
+/*
+ Modified MIT License
+
+ Copyright 2024 OneSignal
+
+ Permission is hereby granted, free of charge, to any person obtaining a copy
+ of this software and associated documentation files (the "Software"), to deal
+ in the Software without restriction, including without limitation the rights
+ to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ copies of the Software, and to permit persons to whom the Software is
+ furnished to do so, subject to the following conditions:
+
+ 1. The above copyright notice and this permission notice shall be included in
+ all copies or substantial portions of the Software.
+
+ 2. All copies of substantial portions of the Software may only be used in connection
+ with services provided by OneSignal.
+
+ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ THE SOFTWARE.
+ */
+
+// Taken from https://swiftrocks.com/thread-safety-in-swift
+// Read http://www.russbishop.net/the-law for more information on why this is necessary
+public final class UnfairLock {
+    private var _lock: UnsafeMutablePointer<os_unfair_lock>
+
+    public init() {
+        _lock = UnsafeMutablePointer<os_unfair_lock>.allocate(capacity: 1)
+        _lock.initialize(to: os_unfair_lock())
+    }
+
+    deinit {
+        _lock.deallocate()
+    }
+
+    public func locked<ReturnValue>(_ closure: () throws -> ReturnValue) rethrows -> ReturnValue {
+        os_unfair_lock_lock(_lock)
+        defer { os_unfair_lock_unlock(_lock) }
+        return try closure()
+    }
+}