Use a recursive lock

* Drop UnfairLock and use NSRecursiveLock
* UnfairLock is fast, but it doesn’t support recursive locking. So, it crashes whenever you lock it twice from the same thread.
* So far, we haven't encountered this, but this is possible, especially if we are not careful about how changes are propagated up.

Author: nan-li

iOS_SDK/OneSignalSDK/OneSignal.xcodeproj/project.pbxproj

@@ -53,7 +53,6 @@
 		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, ); }; };
@@ -944,7 +943,6 @@
 		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>"; };
@@ -1640,14 +1638,6 @@
 			name = Frameworks;
 			sourceTree = "<group>";
 		};
-		3C0590492B86BC5300450D48 /* Utils */ = {
-			isa = PBXGroup;
-			children = (
-				3C05904A2B86BC9E00450D48 /* UnfairLock.swift */,
-			);
-			path = Utils;
-			sourceTree = "<group>";
-		};
 		3C115162289A259500565C41 /* OneSignalOSCore */ = {
 			isa = PBXGroup;
 			children = (
@@ -1661,7 +1651,6 @@
 			isa = PBXGroup;
 			children = (
 				3C115163289A259500565C41 /* OneSignalOSCore.h */,
-				3C0590492B86BC5300450D48 /* Utils */,
 				3C115188289ADEA300565C41 /* OSModelStore.swift */,
 				3C115186289ADE7700565C41 /* OSModelStoreListener.swift */,
 				3C115184289ADE4F00565C41 /* OSModel.swift */,
@@ -3338,7 +3327,6 @@
 				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/Utils/UnfairLock.swift

@@ -40,7 +40,7 @@ class OSIdentityModel: OSModel {
 
     // All access to aliases should go through helper methods with locking
     var aliases: [String: String] = [:]
-    private let aliasesLock = UnfairLock()
+    private let aliasesLock = NSRecursiveLock()
 
     // TODO: We need to make this token secure
     public var jwtBearerToken: String?
@@ -54,7 +54,7 @@ class OSIdentityModel: OSModel {
     }
 
     override func encode(with coder: NSCoder) {
-        aliasesLock.locked {
+        aliasesLock.withLock {
             super.encode(with: coder)
             coder.encode(aliases, forKey: "aliases")
         }
@@ -71,14 +71,14 @@ class OSIdentityModel: OSModel {
 
     /** Threadsafe getter for an alias */
     private func internalGetAlias(_ label: String) -> String? {
-        aliasesLock.locked {
+        aliasesLock.withLock {
             return self.aliases[label]
         }
     }
 
     /** Threadsafe setter or removal for aliases */
     private func internalAddAliases(_ aliases: [String: String]) {
-        aliasesLock.locked {
+        aliasesLock.withLock {
             for (label, id) in aliases {
                 // Remove the alias if the ID field is ""
                 self.aliases[label] = id.isEmpty ? nil : id
@@ -91,7 +91,7 @@ class OSIdentityModel: OSModel {
      Called to clear the model's data in preparation for hydration via a fetch user call.
      */
     func clearData() {
-        aliasesLock.locked {
+        aliasesLock.withLock {
             self.aliases = [:]
         }
     }

iOS_SDK/OneSignalSDK/OneSignalUser/Source/OSIdentityModel.swift

@@ -82,7 +82,7 @@ class OSPropertiesModel: OSModel {
     var timezoneId = TimeZone.current.identifier
 
     var tags: [String: String] = [:]
-    private let tagsLock = UnfairLock()
+    private let tagsLock = NSRecursiveLock()
 
     // MARK: - Initialization
 
@@ -102,7 +102,7 @@ class OSPropertiesModel: OSModel {
     }
 
     override func encode(with coder: NSCoder) {
-        tagsLock.locked {
+        tagsLock.withLock {
             super.encode(with: coder)
             coder.encode(language, forKey: "language")
             coder.encode(tags, forKey: "tags")
@@ -127,15 +127,15 @@ class OSPropertiesModel: OSModel {
      */
     func clearData() {
         // TODO: What about language, lat, long?
-        tagsLock.locked {
+        tagsLock.withLock {
             self.tags = [:]
         }
     }
 
     // MARK: - Tag Methods
 
     func addTags(_ tags: [String: String]) {
-        tagsLock.locked {
+        tagsLock.withLock {
             for (key, value) in tags {
                 self.tags[key] = value
             }
@@ -144,7 +144,7 @@ class OSPropertiesModel: OSModel {
     }
 
     func removeTags(_ tags: [String]) {
-        tagsLock.locked {
+        tagsLock.withLock {
             var tagsToSend: [String: String] = [:]
             for tag in tags {
                 self.tags.removeValue(forKey: tag)
@@ -160,7 +160,7 @@ class OSPropertiesModel: OSModel {
             case "language":
                 self.language = property.value as? String
             case "tags":
-                tagsLock.locked {
+                tagsLock.withLock {
                     self.tags = property.value as? [String: String] ?? [:]
                 }
             default: