Allow querying Bluetooth service status on iOS (Apple) (#1100)

* Fix querying of Bluetooth service status

Makes `checkServiceStatus` async.
Keeps track of `PermissionStrategy` in `PermissionManager`.
Updates example app's displayed permissions.

* Fix memory leak

* Update `BluetoothPermissionStrategy.m`

permission_handler_apple/CHANGELOG.md

+## 9.1.4
+
+* Adds checking whether Bluetooth service is enabled through `Permission.bluetooth.serviceStatus`.
+
 ## 9.1.3
 
 * Fixes an issue where the `Permission.location.request()`, `Permission.locationWhenInUse.request()` and `Permission.locationAlways.request()` calls returned `PermissionStatus.denied` regardless of the actual permission status.

permission_handler_apple/example/lib/main.dart

@@ -36,8 +36,8 @@ class _PermissionHandlerWidgetState extends State<PermissionHandlerWidget> {
           children: Permission.values
               .where((permission) {
                 return permission != Permission.unknown &&
+                    permission != Permission.phone &&
                     permission != Permission.sms &&
-                    permission != Permission.storage &&
                     permission != Permission.ignoreBatteryOptimizations &&
                     permission != Permission.accessMediaLocation &&
                     permission != Permission.activityRecognition &&
@@ -47,7 +47,12 @@ class _PermissionHandlerWidgetState extends State<PermissionHandlerWidget> {
                     permission != Permission.accessNotificationPolicy &&
                     permission != Permission.bluetoothScan &&
                     permission != Permission.bluetoothAdvertise &&
-                    permission != Permission.bluetoothConnect;
+                    permission != Permission.bluetoothConnect &&
+                    permission != Permission.nearbyWifiDevices &&
+                    permission != Permission.videos &&
+                    permission != Permission.audio &&
+                    permission != Permission.scheduleExactAlarm &&
+                    permission != Permission.sensorsAlways;
               })
               .map((permission) => PermissionWidget(permission))
               .toList()),

permission_handler_apple/ios/Classes/PermissionManager.m

@@ -26,9 +26,17 @@
 }
 
 + (void)checkServiceStatus:(enum PermissionGroup)permission result:(FlutterResult)result {
-    id <PermissionStrategy> permissionStrategy = [PermissionManager createPermissionStrategy:permission];
-    ServiceStatus status = [permissionStrategy checkServiceStatus:permission];
-    result([Codec encodeServiceStatus:status]);
+    __block id <PermissionStrategy> permissionStrategy = [PermissionManager createPermissionStrategy:permission];
+    
+    [permissionStrategy checkServiceStatus:permission completionHandler:^(ServiceStatus serviceStatus) {
+        result([Codec encodeServiceStatus:serviceStatus]);
+        
+        // Make sure `result` is called before cleaning up the reference
+        // otherwise the `result` block is also dereferenced on iOS 12 and
+        // below (this is most likely a bug in Objective-C which is solved in the
+        // later versions of the runtime).
+        permissionStrategy = nil;
+    }];
 }
 
 - (void)requestPermissions:(NSArray *)permissions completion:(PermissionRequestCompletion)completion {

permission_handler_apple/ios/Classes/strategies/AppTrackingTransparencyPermissionStrategy.m

@@ -20,8 +20,8 @@
     return PermissionStatusGranted;
 }
 
-- (ServiceStatus)checkServiceStatus:(PermissionGroup)permission {
-    return ServiceStatusNotApplicable;
+- (void)checkServiceStatus:(PermissionGroup)permission completionHandler:(ServiceStatusHandler)completionHandler {
+    completionHandler(ServiceStatusNotApplicable);
 }
 
 - (void)requestPermission:(PermissionGroup)permission completionHandler:(PermissionStatusHandler)completionHandler {

permission_handler_apple/ios/Classes/strategies/AudioVideoPermissionStrategy.m

@@ -22,8 +22,8 @@
     return PermissionStatusDenied;
 }
 
-- (ServiceStatus)checkServiceStatus:(PermissionGroup)permission {
-    return ServiceStatusNotApplicable;
+- (void)checkServiceStatus:(PermissionGroup)permission completionHandler:(ServiceStatusHandler)completionHandler {
+    completionHandler(ServiceStatusNotApplicable);
 }
 
 - (void)requestPermission:(PermissionGroup)permission completionHandler:(PermissionStatusHandler)completionHandler {

permission_handler_apple/ios/Classes/strategies/BluetoothPermissionStrategy.m

@@ -11,8 +11,9 @@
 
 @implementation BluetoothPermissionStrategy {
     CBCentralManager *_centralManager;
-    PermissionStatusHandler _permissionStatusHandler;
     PermissionGroup _requestedPermission;
+    PermissionStatusHandler _permissionStatusHandler;
+    ServiceStatusHandler _serviceStatusHandler;
 }
 
 - (void)initManagerIfNeeded {
@@ -22,24 +23,51 @@
     }
 }
 
+/// Reads the permission status of the Bluetooth service.
+///
+/// The behavior differs across iOS versions:
+/// - Starting with iOS 13.1, this function returns the expected result.
+/// - On iOS 13.0, applications are unable to check for the permission status without triggering a
+/// permission request. Therefore, `PermissionStatusDenied` is always returned. To obtain the
+/// actual permission status, the application should request permission using `requestPermission()`.
+/// If the permission was already granted, no dialog will pop up.
+/// - Below iOS 13.0, applications do not have to ask for permission to use Bluetooth. Therefore,
+/// `PermissionStatusGranted` is always returned.
 - (PermissionStatus)checkPermissionStatus:(PermissionGroup)permission {
-    [self initManagerIfNeeded];
     if (@available(iOS 13.1, *)) {
-        CBManagerAuthorization blePermission = [_centralManager authorization];
-        return [BluetoothPermissionStrategy parsePermission:blePermission];
-    } else if (@available(iOS 13.0, *)){
-        CBManagerAuthorization blePermission =  [_centralManager authorization];
+        CBManagerAuthorization blePermission = [CBCentralManager authorization];
+        
         return [BluetoothPermissionStrategy parsePermission:blePermission];
+    } else if (@available(iOS 13.0, *)) {
+        return PermissionStatusDenied;
     }
     return PermissionStatusGranted;
 }
 
-- (ServiceStatus)checkServiceStatus:(PermissionGroup)permission {
+/// Asynchronously requests the status of the Bluetooth service.
+///
+/// The result will be fetched in `handleCheckServiceStatusCallback`, which will in turn call
+/// `completionHandler` with either `ServiceStatusEnabled` or `ServiceStatusDisabled`.
+///
+/// If the Bluetooth permission has been requested and was denied, this will return `ServiceStatusDisabled`,
+/// regardless of the actual state of the Bluetooth service.
+/// If the Bluetooth permission has not been granted or denied yet, this call will trigger a permission dialog, asking
+/// the user to give the application access to Bluetooth.
+- (void)checkServiceStatus:(PermissionGroup)permission completionHandler:(ServiceStatusHandler)completionHandler {
     [self initManagerIfNeeded];
+    
+    _serviceStatusHandler = completionHandler;
+    _requestedPermission = permission;
+}
+
+- (void)handleCheckServiceStatusCallback:(CBCentralManager *)centralManager {
     if (@available(iOS 10, *)) {
-        return [_centralManager state] == CBManagerStatePoweredOn ? ServiceStatusEnabled : ServiceStatusDisabled;
+        ServiceStatus serviceStatus = [centralManager state] == CBManagerStatePoweredOn ? ServiceStatusEnabled : ServiceStatusDisabled;
+        _serviceStatusHandler(serviceStatus);
     }
-    return [_centralManager state] == CBCentralManagerStatePoweredOn ? ServiceStatusEnabled : ServiceStatusDisabled;
+    #pragma clang diagnostic ignored "-Wdeprecated-declarations"
+    ServiceStatus serviceStatus = [centralManager state] == CBCentralManagerStatePoweredOn ? ServiceStatusEnabled : ServiceStatusDisabled;
+    _serviceStatusHandler(serviceStatus);
 }
 
 - (void)requestPermission:(PermissionGroup)permission completionHandler:(PermissionStatusHandler)completionHandler {
@@ -55,7 +83,17 @@
     _requestedPermission = permission;
 }
 
-+ (PermissionStatus)parsePermission:(CBManagerAuthorization)bluetoothPermission API_AVAILABLE(ios(13)){
+- (void)handleRequestPermissionCallback:(CBCentralManager *)centralManager {
+    if (@available(iOS 13.0, *)) {
+        CBManagerAuthorization blePermission = [centralManager authorization];
+        PermissionStatus permissionStatus = [BluetoothPermissionStrategy parsePermission:blePermission];
+        _permissionStatusHandler(permissionStatus);
+    } else {
+        _permissionStatusHandler(PermissionStatusGranted);
+    }
+}
+
++ (PermissionStatus)parsePermission:(CBManagerAuthorization)bluetoothPermission API_AVAILABLE(ios(13)) {
     switch(bluetoothPermission){
         case CBManagerAuthorizationNotDetermined:
             return PermissionStatusDenied;
@@ -69,8 +107,13 @@
 }
 
 - (void)centralManagerDidUpdateState:(nonnull CBCentralManager *)centralManager {
-    PermissionStatus permissionStatus = [self checkPermissionStatus:_requestedPermission];
-    _permissionStatusHandler(permissionStatus);
+    if (_permissionStatusHandler != nil) {
+        [self handleRequestPermissionCallback:centralManager];
+    }
+    
+    if (_serviceStatusHandler != nil) {
+        [self handleCheckServiceStatusCallback:centralManager];
+    }
 }
 
 @end

permission_handler_apple/ios/Classes/strategies/ContactPermissionStrategy.m

@@ -13,8 +13,8 @@
     return [ContactPermissionStrategy permissionStatus];
 }
 
-- (ServiceStatus)checkServiceStatus:(PermissionGroup)permission {
-    return ServiceStatusNotApplicable;
+- (void)checkServiceStatus:(PermissionGroup)permission completionHandler:(ServiceStatusHandler)completionHandler {
+    completionHandler(ServiceStatusNotApplicable);
 }
 
 - (void)requestPermission:(PermissionGroup)permission completionHandler:(PermissionStatusHandler)completionHandler {

permission_handler_apple/ios/Classes/strategies/CriticalAlertsPermissionStrategy.m

@@ -15,8 +15,8 @@
   return [CriticalAlertsPermissionStrategy permissionStatus];
 }
 
-- (ServiceStatus)checkServiceStatus:(PermissionGroup)permission {
-  return ServiceStatusNotApplicable;
+- (void)checkServiceStatus:(PermissionGroup)permission completionHandler:(ServiceStatusHandler)completionHandler {
+    completionHandler(ServiceStatusNotApplicable);
 }
 
 - (void)requestPermission:(PermissionGroup)permission completionHandler:(PermissionStatusHandler)completionHandler {

permission_handler_apple/ios/Classes/strategies/EventPermissionStrategy.m

@@ -23,8 +23,8 @@
     return PermissionStatusDenied;
 }
 
-- (ServiceStatus)checkServiceStatus:(PermissionGroup)permission {
-    return ServiceStatusNotApplicable;
+- (void)checkServiceStatus:(PermissionGroup)permission completionHandler:(ServiceStatusHandler)completionHandler {
+    completionHandler(ServiceStatusNotApplicable);
 }
 
 - (void)requestPermission:(PermissionGroup)permission completionHandler:(PermissionStatusHandler)completionHandler {

permission_handler_apple/ios/Classes/strategies/LocationPermissionStrategy.m

@@ -35,8 +35,8 @@ NSString *const UserDefaultPermissionRequestedKey = @"org.baseflow.permission_ha
     return [LocationPermissionStrategy permissionStatus:permission];
 }
 
-- (ServiceStatus)checkServiceStatus:(PermissionGroup)permission {
-    return [CLLocationManager locationServicesEnabled] ? ServiceStatusEnabled : ServiceStatusDisabled;
+- (void)checkServiceStatus:(PermissionGroup)permission completionHandler:(ServiceStatusHandler)completionHandler {
+    completionHandler([CLLocationManager locationServicesEnabled] ? ServiceStatusEnabled : ServiceStatusDisabled);
 }
 
 - (void)requestPermission:(PermissionGroup)permission completionHandler:(PermissionStatusHandler)completionHandler {

permission_handler_apple/ios/Classes/strategies/MediaLibraryPermissionStrategy.m

@@ -13,8 +13,8 @@
     return [MediaLibraryPermissionStrategy permissionStatus];
 }
 
-- (ServiceStatus)checkServiceStatus:(PermissionGroup)permission {
-    return ServiceStatusNotApplicable;
+- (void)checkServiceStatus:(PermissionGroup)permission completionHandler:(ServiceStatusHandler)completionHandler {
+    completionHandler(ServiceStatusNotApplicable);
 }
 
 - (void)requestPermission:(PermissionGroup)permission completionHandler:(PermissionStatusHandler)completionHandler {

permission_handler_apple/ios/Classes/strategies/NotificationPermissionStrategy.m

@@ -15,8 +15,8 @@
   return [NotificationPermissionStrategy permissionStatus];
 }
 
-- (ServiceStatus)checkServiceStatus:(PermissionGroup)permission {
-  return ServiceStatusNotApplicable;
+- (void)checkServiceStatus:(PermissionGroup)permission completionHandler:(ServiceStatusHandler)completionHandler {
+    completionHandler(ServiceStatusNotApplicable);
 }
 
 - (void)requestPermission:(PermissionGroup)permission completionHandler:(PermissionStatusHandler)completionHandler {

permission_handler_apple/ios/Classes/strategies/PermissionStrategy.h

@@ -6,12 +6,13 @@
 #import <Foundation/Foundation.h>
 #import "PermissionHandlerEnums.h"
 
+typedef void (^ServiceStatusHandler)(ServiceStatus serviceStatus);
 typedef void (^PermissionStatusHandler)(PermissionStatus permissionStatus);
 
 @protocol PermissionStrategy <NSObject>
 - (PermissionStatus)checkPermissionStatus:(PermissionGroup)permission;
 
-- (ServiceStatus)checkServiceStatus:(PermissionGroup)permission;
+- (void)checkServiceStatus:(PermissionGroup)permission completionHandler:(ServiceStatusHandler)completionHandler;
 
 - (void)requestPermission:(PermissionGroup)permission completionHandler:(PermissionStatusHandler)completionHandler;
 @end

permission_handler_apple/ios/Classes/strategies/PhonePermissionStrategy.m

@@ -16,13 +16,12 @@
   return PermissionStatusDenied;
 }
 
-- (ServiceStatus)checkServiceStatus:(PermissionGroup)permission {
+- (void)checkServiceStatus:(PermissionGroup)permission completionHandler:(ServiceStatusHandler)completionHandler {
   // https://stackoverflow.com/a/5095058
   if (![[UIApplication sharedApplication] canOpenURL:[NSURL URLWithString:@"tel://"]]) {
-    return ServiceStatusNotApplicable;
+      completionHandler(ServiceStatusNotApplicable);
   }
-  
-  return [self canDevicePlaceAPhoneCall] ? ServiceStatusEnabled : ServiceStatusDisabled;
+  completionHandler([self canDevicePlaceAPhoneCall] ? ServiceStatusEnabled : ServiceStatusDisabled);
 }
 
 - (void)requestPermission:(PermissionGroup)permission completionHandler:(PermissionStatusHandler)completionHandler {

permission_handler_apple/ios/Classes/strategies/PhotoPermissionStrategy.m

@@ -24,8 +24,8 @@
     return [PhotoPermissionStrategy permissionStatus:addOnlyAccessLevel];
 }
 
-- (ServiceStatus)checkServiceStatus:(PermissionGroup)permission {
-    return ServiceStatusNotApplicable;
+- (void)checkServiceStatus:(PermissionGroup)permission completionHandler:(ServiceStatusHandler)completionHandler {
+    completionHandler(ServiceStatusNotApplicable);
 }
 
 - (void)requestPermission:(PermissionGroup)permission completionHandler:(PermissionStatusHandler)completionHandler {

permission_handler_apple/ios/Classes/strategies/SensorPermissionStrategy.m

@@ -12,14 +12,15 @@
     return [SensorPermissionStrategy permissionStatus];
 }
 
-- (ServiceStatus)checkServiceStatus:(PermissionGroup)permission {
+- (void)checkServiceStatus:(PermissionGroup)permission completionHandler:(ServiceStatusHandler)completionHandler {
     if (@available(iOS 11.0, *)) {
-        return [CMMotionActivityManager isActivityAvailable]
+        completionHandler([CMMotionActivityManager isActivityAvailable]
           ? ServiceStatusEnabled
-        : ServiceStatusDisabled;
+          : ServiceStatusDisabled
+        );
     }
     
-    return ServiceStatusDisabled;
+    completionHandler(ServiceStatusDisabled);
 }
 
 - (void)requestPermission:(PermissionGroup)permission completionHandler:(PermissionStatusHandler)completionHandler {

permission_handler_apple/ios/Classes/strategies/SpeechPermissionStrategy.m

@@ -12,8 +12,8 @@
     return [SpeechPermissionStrategy permissionStatus];
 }
 
-- (ServiceStatus)checkServiceStatus:(PermissionGroup)permission {
-    return ServiceStatusNotApplicable;
+- (void)checkServiceStatus:(PermissionGroup)permission completionHandler:(ServiceStatusHandler)completionHandler {
+    completionHandler(ServiceStatusNotApplicable);
 }
 
 - (void)requestPermission:(PermissionGroup)permission completionHandler:(PermissionStatusHandler)completionHandler {

permission_handler_apple/ios/Classes/strategies/StoragePermissionStrategy.m

@@ -13,8 +13,8 @@
     return [StoragePermissionStrategy permissionStatus];
 }
 
-- (ServiceStatus)checkServiceStatus:(PermissionGroup)permission {
-    return ServiceStatusNotApplicable;
+- (void)checkServiceStatus:(PermissionGroup)permission completionHandler:(ServiceStatusHandler)completionHandler {
+    completionHandler(ServiceStatusNotApplicable);
 }
 
 - (void)requestPermission:(PermissionGroup)permission completionHandler:(PermissionStatusHandler)completionHandler {

permission_handler_apple/ios/Classes/strategies/UnknownPermissionStrategy.m

@@ -12,8 +12,8 @@
     return PermissionStatusDenied;
 }
 
-- (ServiceStatus)checkServiceStatus:(PermissionGroup)permission {
-    return ServiceStatusDisabled;
+- (void)checkServiceStatus:(PermissionGroup)permission completionHandler:(ServiceStatusHandler)completionHandler {
+    completionHandler(ServiceStatusDisabled);
 }
 
 - (void)requestPermission:(PermissionGroup)permission completionHandler:(PermissionStatusHandler)completionHandler {

permission_handler_apple/pubspec.yaml

@@ -2,7 +2,7 @@ name: permission_handler_apple
 description: Permission plugin for Flutter. This plugin provides the iOS API to request and check permissions.
 repository: https://github.com/baseflow/flutter-permission-handler
 issue_tracker: https://github.com/Baseflow/flutter-permission-handler/issues
-version: 9.1.3
+version: 9.1.4
 
 environment:
   sdk: ">=2.15.0 <4.0.0"
@@ -18,7 +18,7 @@ flutter:
 dependencies:
   flutter:
     sdk: flutter
-  permission_handler_platform_interface: ^3.11.0
+  permission_handler_platform_interface: ^3.11.2
 
 dev_dependencies:
   flutter_lints: ^1.0.4