Merge pull request #878 from Microsoft/develop

Release 1.1.0

AppCenter.podspec

@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
   s.name              = 'AppCenter'
-  s.version           = '1.0.1'
+  s.version           = '1.1.0'
 
   s.summary           = 'Visual Studio App Center is your continuous integration, delivery and learning solution for iOS and macOS apps.'
   s.description       = <<-DESC
@@ -35,7 +35,7 @@ Pod::Spec.new do |s|
 
   s.ios.preserve_path = 'AppCenter-SDK-Apple/iOS/README.md'
   s.osx.preserve_path = 'AppCenter-SDK-Apple/macOS/README.md'
-  
+
   s.default_subspecs = 'Analytics', 'Crashes'
 
   s.subspec 'Core' do |ss|

AppCenter/AppCenter.xcodeproj/project.pbxproj

@@ -306,6 +306,9 @@
 		04FD126F1E415697007ABFE7 /* MSLogManagerDefaultPrivate.h in Headers */ = {isa = PBXBuildFile; fileRef = 04FD126E1E415697007ABFE7 /* MSLogManagerDefaultPrivate.h */; };
 		3592ABA71DC90E3600EF4592 /* MSLogger.h in Headers */ = {isa = PBXBuildFile; fileRef = 3592ABA51DC90E3600EF4592 /* MSLogger.h */; };
 		3592ABA81DC90E3600EF4592 /* MSLogger.m in Sources */ = {isa = PBXBuildFile; fileRef = 3592ABA61DC90E3600EF4592 /* MSLogger.m */; };
+		35C0E3CB1FD6146A004E841E /* MSMockSecondService.m in Sources */ = {isa = PBXBuildFile; fileRef = 35C0E3C91FD6146A004E841E /* MSMockSecondService.m */; };
+		35C0E3CC1FD6146A004E841E /* MSMockSecondService.m in Sources */ = {isa = PBXBuildFile; fileRef = 35C0E3C91FD6146A004E841E /* MSMockSecondService.m */; };
+		35C0E3CD1FD6146A004E841E /* MSMockSecondService.m in Sources */ = {isa = PBXBuildFile; fileRef = 35C0E3C91FD6146A004E841E /* MSMockSecondService.m */; };
 		35D0B7531DDFABFD003EACCD /* MSWrapperLogger.h in Headers */ = {isa = PBXBuildFile; fileRef = 35D0B7511DDFABFD003EACCD /* MSWrapperLogger.h */; };
 		35D0B7541DDFABFD003EACCD /* MSWrapperLogger.m in Sources */ = {isa = PBXBuildFile; fileRef = 35D0B7521DDFABFD003EACCD /* MSWrapperLogger.m */; };
 		380A4DCB1DD6908A00E99219 /* MSUtilityTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 380A4DCA1DD6908A00E99219 /* MSUtilityTests.m */; };
@@ -327,6 +330,7 @@
 		385AD9221D95898D008B354A /* MSServiceAbstractProtected.h in Headers */ = {isa = PBXBuildFile; fileRef = 385AD9211D95898D008B354A /* MSServiceAbstractProtected.h */; };
 		385FC0551D37EBD700A1799F /* MSDeviceTrackerTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 385FC0541D37EBD700A1799F /* MSDeviceTrackerTests.m */; };
 		38641B051EB0F40800B2CE73 /* MSAppDelegateForwarderTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 38641B041EB0F40800B2CE73 /* MSAppDelegateForwarderTests.m */; };
+		386A69ED1FD8843D0057B316 /* MSKeychainUtilPrivate.h in Headers */ = {isa = PBXBuildFile; fileRef = 386A69EC1FD8843D0057B316 /* MSKeychainUtilPrivate.h */; };
 		386E8D931E25932100EECF0F /* MSHttpTestUtil.m in Sources */ = {isa = PBXBuildFile; fileRef = 386E8D911E25932100EECF0F /* MSHttpTestUtil.m */; };
 		387C75811D6270A300D68CC1 /* MSServiceAbstractInternal.h in Headers */ = {isa = PBXBuildFile; fileRef = 387C757F1D6270A300D68CC1 /* MSServiceAbstractInternal.h */; };
 		387C758F1D64E50800D68CC1 /* MSServiceCommon.h in Headers */ = {isa = PBXBuildFile; fileRef = 387C758D1D64DF2500D68CC1 /* MSServiceCommon.h */; };
@@ -587,6 +591,8 @@
 		04FD126E1E415697007ABFE7 /* MSLogManagerDefaultPrivate.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = MSLogManagerDefaultPrivate.h; sourceTree = "<group>"; };
 		3592ABA51DC90E3600EF4592 /* MSLogger.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = MSLogger.h; sourceTree = "<group>"; };
 		3592ABA61DC90E3600EF4592 /* MSLogger.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = MSLogger.m; sourceTree = "<group>"; };
+		35C0E3C91FD6146A004E841E /* MSMockSecondService.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = MSMockSecondService.m; sourceTree = "<group>"; };
+		35C0E3CA1FD6146A004E841E /* MSMockSecondService.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = MSMockSecondService.h; sourceTree = "<group>"; };
 		35D0B7511DDFABFD003EACCD /* MSWrapperLogger.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = MSWrapperLogger.h; sourceTree = "<group>"; };
 		35D0B7521DDFABFD003EACCD /* MSWrapperLogger.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = MSWrapperLogger.m; sourceTree = "<group>"; };
 		380A4DCA1DD6908A00E99219 /* MSUtilityTests.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = MSUtilityTests.m; sourceTree = "<group>"; };
@@ -608,6 +614,7 @@
 		385AD9211D95898D008B354A /* MSServiceAbstractProtected.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = MSServiceAbstractProtected.h; sourceTree = "<group>"; };
 		385FC0541D37EBD700A1799F /* MSDeviceTrackerTests.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = MSDeviceTrackerTests.m; sourceTree = "<group>"; };
 		38641B041EB0F40800B2CE73 /* MSAppDelegateForwarderTests.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = MSAppDelegateForwarderTests.m; sourceTree = "<group>"; };
+		386A69EC1FD8843D0057B316 /* MSKeychainUtilPrivate.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = MSKeychainUtilPrivate.h; sourceTree = "<group>"; };
 		386E8D911E25932100EECF0F /* MSHttpTestUtil.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = MSHttpTestUtil.m; sourceTree = "<group>"; };
 		386E8D921E25932100EECF0F /* MSHttpTestUtil.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = MSHttpTestUtil.h; sourceTree = "<group>"; };
 		387C757F1D6270A300D68CC1 /* MSServiceAbstractInternal.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; lineEnding = 0; path = MSServiceAbstractInternal.h; sourceTree = "<group>"; xcLanguageSpecificationIdentifier = xcode.lang.objcpp; };
@@ -997,8 +1004,9 @@
 				B2CD749A1F22BE270070E7DF /* MSUtility+File.m */,
 				B2CD749B1F22BE270070E7DF /* MSUtility+StringFormatting.h */,
 				B2CD749C1F22BE270070E7DF /* MSUtility+StringFormatting.m */,
-				045BC3161E3FD88600B6C960 /* MSKeychainUtil.m */,
 				045BC3181E3FD8AC00B6C960 /* MSKeychainUtil.h */,
+				045BC3161E3FD88600B6C960 /* MSKeychainUtil.m */,
+				386A69EC1FD8843D0057B316 /* MSKeychainUtilPrivate.h */,
 			);
 			path = Util;
 			sourceTree = "<group>";
@@ -1115,6 +1123,8 @@
 				D377A30C1E83A05900B2C97A /* MSMockUserDefaults.m */,
 				805F3F691F209C8A00B489E4 /* MSMockService.h */,
 				805F3F6A1F209C9D00B489E4 /* MSMockService.m */,
+				35C0E3CA1FD6146A004E841E /* MSMockSecondService.h */,
+				35C0E3C91FD6146A004E841E /* MSMockSecondService.m */,
 				04311FEE1EE083C2007054C5 /* MSTestFrameworks.h */,
 			);
 			path = Util;
@@ -1401,6 +1411,7 @@
 				B2CD745E1F22BBBB0070E7DF /* MSWrapperSdkInternal.h in Headers */,
 				04754F431EA980FD002CBA46 /* MSDeviceTrackerPrivate.h in Headers */,
 				E8AEE9821D5970A400C0FF6C /* MSLogManagerDelegate.h in Headers */,
+				386A69ED1FD8843D0057B316 /* MSKeychainUtilPrivate.h in Headers */,
 				3844FF211E8C2716003E9194 /* MSDevice.h in Headers */,
 				6E04016C1D1C9E1F0051BCFA /* AppCenter.h in Headers */,
 				E84B8E351D235226006FD231 /* MSHttpSender.h in Headers */,
@@ -1748,6 +1759,7 @@
 				0446DF171F3B864600C8E338 /* MSServiceAbstractTests.m in Sources */,
 				0446DF181F3B864600C8E338 /* MSChannelConfigurationTests.m in Sources */,
 				0446DF191F3B864600C8E338 /* MSLoggerTests.m in Sources */,
+				35C0E3CB1FD6146A004E841E /* MSMockSecondService.m in Sources */,
 				0446DF1B1F3B864600C8E338 /* MSSenderUtilTests.m in Sources */,
 				0446DF1C1F3B864600C8E338 /* MSMockLog.m in Sources */,
 				0446DF1D1F3B864600C8E338 /* MSLogManagerDefaultTests.m in Sources */,
@@ -1772,6 +1784,7 @@
 				04A140891ECE63C3001CEE94 /* MSLoggerTests.m in Sources */,
 				046AEAE31ECA562A00CBE511 /* MSKeychainUtilTests.m in Sources */,
 				04A1408B1ECE63CB001CEE94 /* MSIngestionSenderTests.m in Sources */,
+				35C0E3CC1FD6146A004E841E /* MSMockSecondService.m in Sources */,
 				046AEAE41ECA562A00CBE511 /* MSStartServiceLogTests.m in Sources */,
 				0446DF331F3B870A00C8E338 /* MSLogDBStorageTests.m in Sources */,
 				046AEAE61ECA562A00CBE511 /* MSChannelConfigurationTests.m in Sources */,
@@ -1887,6 +1900,7 @@
 				B2FD53651E567BCF0050F909 /* MSDeviceHistoryInfoTests.m in Sources */,
 				380A4DCB1DD6908A00E99219 /* MSUtilityTests.m in Sources */,
 				3849BA7E1EF3489D0072E3E0 /* MSDBStorageTests.m in Sources */,
+				35C0E3CD1FD6146A004E841E /* MSMockSecondService.m in Sources */,
 				E829E4231D25C8BA00F19DA1 /* MSIngestionSenderTests.m in Sources */,
 				805F3F6B1F209C9D00B489E4 /* MSMockService.m in Sources */,
 				E88EBBFB1D2C8CC7007E7785 /* MSLogContainerTests.m in Sources */,

AppCenter/AppCenter/Internals/Channel/MSChannelDefault.m

@@ -194,7 +194,7 @@ - (void)flushQueue {
 
                           // Failure.
                           else {
-                            MSLogDebug([MSAppCenter logTag], @"Log(s) sent with failure, batch Id:%@, status code:%lu",
+                            MSLogError([MSAppCenter logTag], @"Log(s) sent with failure, batch Id:%@, status code:%lu",
                                        senderBatchId, (unsigned long)statusCode);
 
                             // Notify delegates.

AppCenter/AppCenter/Internals/Device/MSDeviceTracker.m

@@ -298,7 +298,30 @@ - (NSString *)osBuild {
 }
 
 - (NSString *)locale:(NSLocale *)currentLocale {
-  return [currentLocale objectForKey:NSLocaleIdentifier];
+
+  /*
+   * [currentLocale objectForKey:NSLocaleIdentifier] will return an alternate language if a language set in system is
+   * not supported by applications. If system language is set to en_US but an application doesn't support en_US, for
+   * example, the OS will return the next application supported language in Preferred Language Order list unless there
+   * is only one language in the list. The method will return the first language in the list to prevent from the above
+   * scenario.
+   *
+   * In addition to that;
+   *     1. preferred language returns "-" instead of "_" as a delimiter of language code and country code, the method
+   * will concatenate language code and country code with "_" and return it.
+   *     2. some languages can be set without country code so region code can be returned in this case.
+   *     3. some langugaes have script code which differentiate languages. E.g. zh-Hans and zh-Hant. This is a possible
+   * scenario in Apple platforms that a locale can be zh_CN for Traditional Chinese. The method will return zh-Hant_CN
+   * in this case to make sure system language is Traditional Chinese even though region is set to China.
+   */
+  NSLocale *preferredLanguage = [[NSLocale alloc] initWithLocaleIdentifier:[NSLocale preferredLanguages][0]];
+  NSString *languageCode = [preferredLanguage objectForKey:NSLocaleLanguageCode];
+  NSString *scriptCode = [preferredLanguage objectForKey:NSLocaleScriptCode];
+  NSString *countryCode = [preferredLanguage objectForKey:NSLocaleCountryCode];
+  NSString *locale = [NSString stringWithFormat:@"%@%@_%@", languageCode,
+                                                (scriptCode ? [NSString stringWithFormat:@"-%@", scriptCode] : @""),
+                                                countryCode ?: [currentLocale objectForKey:NSLocaleCountryCode]];
+  return locale;
 }
 
 - (NSNumber *)timeZoneOffset:(NSTimeZone *)timeZone {

AppCenter/AppCenter/Internals/MSAppCenterInternal.h

@@ -9,6 +9,12 @@
 static NSString *const kMSInstallIdKey = @"MSInstallId";
 static NSString *const kMSAppCenterIsEnabledKey = @"MSAppCenterIsEnabled";
 
+// Name of the environment variable to check for which services should be disabled.
+static NSString *const kMSDisableVariable = @"APP_CENTER_DISABLE";
+
+// Value that would cause all services to be disabled.
+static NSString *const kMSDisableAll = @"All";
+
 @interface MSAppCenter ()
 
 @property(nonatomic) id<MSLogManager> logManager;

AppCenter/AppCenter/Internals/Sender/MSHttpSender.m

@@ -237,7 +237,7 @@ - (void)sendCallAsync:(MSSenderCall *)call {
                   }
                 }
               }
-              MSLogDebug([MSAppCenter logTag], @"HTTP response received with status code=%lu and payload=%@",
+              MSLogVerbose([MSAppCenter logTag], @"HTTP response received with status code=%lu and payload=%@",
                          (unsigned long)statusCode, payload);
 
               // Call handles the completion.
@@ -351,6 +351,13 @@ - (NSURLSession *)session {
     NSURLSessionConfiguration *sessionConfiguration = [NSURLSessionConfiguration defaultSessionConfiguration];
     sessionConfiguration.timeoutIntervalForRequest = kRequestTimeout;
     _session = [NSURLSession sessionWithConfiguration:sessionConfiguration];
+
+    /*
+     * Limit callbacks execution concurrency to avoid race condition. This queue is used only for
+     * delegate method calls and completion handlers.
+     * See https://developer.apple.com/documentation/foundation/nsurlsession/1411571-delegatequeue
+     */
+    _session.delegateQueue.maxConcurrentOperationCount = 1;
   }
   return _session;
 }

AppCenter/AppCenter/Internals/Sender/MSSenderCall.m

@@ -33,14 +33,14 @@ - (uint32_t)delayForRetryCount:(NSUInteger)retryCount {
   return delay;
 }
 
-- (void)startTimer {
+- (void)startRetryTimerWithStatusCode:(NSUInteger)statusCode {
   [self resetTimer];
 
   // Create queue.
   self.timerSource = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0, DISPATCH_TARGET_QUEUE_DEFAULT);
   int64_t delta = NSEC_PER_SEC * [self delayForRetryCount:self.retryCount];
-  MSLogDebug([MSAppCenter logTag], @"Call attempt #%lu failed, it will be retried in %.f ms.",
-             (unsigned long)self.retryCount, round(delta / 1000000));
+  MSLogWarning([MSAppCenter logTag], @"Call attempt #%lu failed with status code: %lu, it will be retried in %.f ms.",
+               (unsigned long)self.retryCount, (unsigned long)statusCode, round(delta / 1000000));
   self.retryCount++;
   dispatch_source_set_timer(self.timerSource, dispatch_walltime(NULL, delta), 1ull * NSEC_PER_SEC, 1ull * NSEC_PER_SEC);
   __weak typeof(self) weakSelf = self;
@@ -84,7 +84,7 @@ - (void)sender:(id<MSSender>)sender
 
   // Retry.
   else if ([MSSenderUtil isRecoverableError:statusCode] && ![self hasReachedMaxRetries]) {
-    [self startTimer];
+    [self startRetryTimerWithStatusCode:statusCode];
   }
 
   // Callback to Channel.

AppCenter/AppCenter/Internals/Util/MSKeychainUtil.h

@@ -24,7 +24,7 @@ NS_ASSUME_NONNULL_BEGIN
  *
  * @return A string data that was deleted.
  */
-+ (NSString *)deleteStringForKey:(NSString *)key;
++ (NSString *_Nullable)deleteStringForKey:(NSString *)key;
 
 /**
  * Get a string from Keychain with the given key.

AppCenter/AppCenter/Internals/Util/MSKeychainUtil.m

@@ -1,32 +1,34 @@
 #import <Foundation/Foundation.h>
 
-#import "MSKeychainUtil.h"
+#import "MSKeychainUtilPrivate.h"
 #import "MSUtility.h"
 
 @implementation MSKeychainUtil
 
-static NSString *AppCenterKeychainServiceName(void) {
+static NSString *AppCenterKeychainServiceName(NSString *suffix) {
   static NSString *serviceName = nil;
   static dispatch_once_t onceToken;
   dispatch_once(&onceToken, ^{
-    serviceName = [NSString stringWithFormat:@"%@.AppCenter", [MS_APP_MAIN_BUNDLE bundleIdentifier]];
+    serviceName = [NSString stringWithFormat:@"%@.%@", [MS_APP_MAIN_BUNDLE bundleIdentifier], suffix];
   });
   return serviceName;
 }
 
-+ (BOOL)storeString:(NSString *)string forKey:(NSString *)key {
-  NSMutableDictionary *item = [MSKeychainUtil generateItem:key];
++ (BOOL)storeString:(NSString *)string forKey:(NSString *)key withServiceName:(NSString *)serviceName {
+  NSMutableDictionary *item = [MSKeychainUtil generateItem:key withServiceName:serviceName];
   item[(__bridge id)kSecValueData] = [string dataUsingEncoding:NSUTF8StringEncoding];
-
   OSStatus status = SecItemAdd((__bridge CFDictionaryRef)item, nil);
   return status == noErr;
 }
 
-+ (NSString *)deleteStringForKey:(NSString *)key {
++ (BOOL)storeString:(NSString *)string forKey:(NSString *)key {
+  return [MSKeychainUtil storeString:string forKey:key withServiceName:AppCenterKeychainServiceName(kMSServiceSuffix)];
+}
+
++ (NSString *)deleteStringForKey:(NSString *)key withServiceName:(NSString *)serviceName {
   NSString *string = [MSKeychainUtil stringForKey:key];
   if (string) {
-    NSMutableDictionary *item = [MSKeychainUtil generateItem:key];
-
+    NSMutableDictionary *item = [MSKeychainUtil generateItem:key withServiceName:serviceName];
     OSStatus status = SecItemDelete((__bridge CFDictionaryRef)item);
     if (status == noErr) {
       return string;
@@ -35,33 +37,38 @@ + (NSString *)deleteStringForKey:(NSString *)key {
   return nil;
 }
 
-+ (NSString *)stringForKey:(NSString *)key {
-  NSMutableDictionary *item = [MSKeychainUtil generateItem:key];
++ (NSString *)deleteStringForKey:(NSString *)key {
+  return [MSKeychainUtil deleteStringForKey:key withServiceName:AppCenterKeychainServiceName(kMSServiceSuffix)];
+}
+
++ (NSString *)stringForKey:(NSString *)key withServiceName:(NSString *)serviceName {
+  NSMutableDictionary *item = [MSKeychainUtil generateItem:key withServiceName:serviceName];
   item[(__bridge id)kSecReturnData] = (__bridge id)kCFBooleanTrue;
   item[(__bridge id)kSecMatchLimit] = (__bridge id)kSecMatchLimitOne;
-
   CFTypeRef data = nil;
   OSStatus status = SecItemCopyMatching((__bridge CFDictionaryRef)item, &data);
-
   if (status == noErr) {
     return [[NSString alloc] initWithData:(__bridge_transfer NSData *)data encoding:NSUTF8StringEncoding];
   }
   return nil;
 }
 
++ (NSString *)stringForKey:(NSString *)key {
+  return [MSKeychainUtil stringForKey:key withServiceName:AppCenterKeychainServiceName(kMSServiceSuffix)];
+}
+
 + (BOOL)clear {
   NSMutableDictionary *item = [NSMutableDictionary new];
   item[(__bridge id)kSecClass] = (__bridge id)kSecClassGenericPassword;
-  item[(__bridge id)kSecAttrService] = AppCenterKeychainServiceName();
-
+  item[(__bridge id)kSecAttrService] = AppCenterKeychainServiceName(kMSServiceSuffix);
   OSStatus status = SecItemDelete((__bridge CFDictionaryRef)item);
   return status == noErr;
 }
 
-+ (NSMutableDictionary *)generateItem:(NSString *)key {
++ (NSMutableDictionary *)generateItem:(NSString *)key withServiceName:(NSString *)serviceName {
   NSMutableDictionary *item = [NSMutableDictionary new];
   item[(__bridge id)kSecClass] = (__bridge id)kSecClassGenericPassword;
-  item[(__bridge id)kSecAttrService] = AppCenterKeychainServiceName();
+  item[(__bridge id)kSecAttrService] = serviceName;
   item[(__bridge id)kSecAttrAccount] = key;
   return item;
 }

AppCenter/AppCenter/Internals/Util/MSKeychainUtilPrivate.h

@@ -0,0 +1,50 @@
+
+
+#import "MSKeychainUtil.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+/**
+ * Keychain service name suffix.
+ */
+static NSString *const kMSServiceSuffix = @"AppCenter";
+
+/**
+ * Utility class for Keychain.
+ */
+@interface MSKeychainUtil ()
+
+/**
+ * Store a string to Keychain with the given key.
+ *
+ * @param string A string data to be placed in Keychain.
+ * @param key A unique key for the data.
+ * @param serviceName Keychain service name.
+ *
+ * @return YES if stored successfully, NO otherwise.
+ */
++ (BOOL)storeString:(NSString *)string forKey:(NSString *)key withServiceName:(NSString *)serviceName;
+
+/**
+ * Delete a string from Keychain with the given key.
+ *
+ * @param key A unique key for the data.
+ * @param serviceName Keychain service name.
+ *
+ * @return A string data that was deleted.
+ */
++ (NSString *_Nullable)deleteStringForKey:(NSString *)key withServiceName:(NSString *)serviceName;
+
+/**
+ * Get a string from Keychain with the given key.
+ *
+ * @param key A unique key for the data.
+ * @param serviceName Keychain service name.
+ *
+ * @return A string data if exists.
+ */
++ (NSString *_Nullable)stringForKey:(NSString *)key withServiceName:(NSString *)serviceName;
+
+@end
+
+NS_ASSUME_NONNULL_END