add new api

permission_handler/lib/permission_handler.dart

-import 'dart:async';
 import 'dart:io';
 import 'dart:io';
 
 
 import 'package:permission_handler_platform_interface/permission_handler_platform_interface.dart';
 import 'package:permission_handler_platform_interface/permission_handler_platform_interface.dart';
 
 
 export 'package:permission_handler_platform_interface/permission_handler_platform_interface.dart'
 export 'package:permission_handler_platform_interface/permission_handler_platform_interface.dart'
-    show PermissionGroup, PermissionStatus, ServiceStatus;
+    show Permission, PermissionStatus, ServiceStatus;
 
 
-/// The Android and iOS implementation of [PermissionHandlerPlatform].
+PermissionHandlerPlatform get _handler => PermissionHandlerPlatform.instance;
+
+/// Opens the app settings page.
 ///
 ///
-/// This class implements the `package:permission_handler` functionality for
-/// the Android and iOS platforms.
-class PermissionHandler extends PermissionHandlerPlatform {
-  @override
-  Future<ServiceStatus> checkServiceStatus(PermissionGroup permission) {
-    return PermissionHandlerPlatform.instance.checkServiceStatus(permission);
-  }
+/// Returns [true] if the app settings page could be opened, otherwise [false].
+Future<bool> openAppSettings() => _handler.openAppSettings();
 
 
-  @override
-  Future<PermissionStatus> checkPermissionStatus(PermissionGroup permission) {
-    return PermissionHandlerPlatform.instance.checkPermissionStatus(permission);
-  }
+/// Actions that can be executed on a permission.
+extension PermissionActions on Permission {
+  /// The current status of this permission.
+  Future<PermissionStatus> get status => _handler.checkPermissionStatus(this);
+
+  /// If you should show a rationale for requesting permission.
+  ///
+  /// This is only implemented on Android, calling this on iOS always returns
+  /// [false].
+  Future<bool> get shouldShowRequestRationale {
+    if (!Platform.isAndroid) {
+      return Future.value(false);
+    }
 
 
-  @override
-  Future<bool> openAppSettings() {
-    return PermissionHandlerPlatform.instance.openAppSettings();
+    return _handler.shouldShowRequestPermissionRationale(this);
   }
   }
 
 
-  @override
-  Future<Map<PermissionGroup, PermissionStatus>> requestPermissions(
-      List<PermissionGroup> permissions) {
-    return PermissionHandlerPlatform.instance.requestPermissions(permissions);
+  /// Request the user for access to this permission.
+  ///
+  /// Returns the new [PermissionStatus].
+  Future<PermissionStatus> request() async {
+    return (await [this].request())[this];
   }
   }
 
 
-  @override
-  Future<bool> shouldShowRequestPermissionRationale(
-      PermissionGroup permission) {
-    if (!Platform.isAndroid) {
-      return Future.value(false);
+  /// Request the user for access to this permission if it [isDenied].
+  ///
+  /// Returns the new [PermissionStatus].
+  Future<PermissionStatus> requestIfDenied() async {
+    final status = await this.status;
+
+    if (status.isDenied) {
+      return request();
     }
     }
+    return status;
+  }
+}
+
+/// Shortcuts for checking the [status] of a permission.
+extension PermissionCheckShortcuts on Permission {
+  /// If the user denied access to the requested feature.
+  Future<bool> get isDenied => status.isDenied;
+
+  /// If the user granted access to the requested feature.
+  Future<bool> get isGranted => status.isGranted;
+
+  /// If the OS denied access to the requested feature. The user cannot change
+  /// this app's status, possibly due to active restrictions such as parental
+  /// controls being in place.
+  /// *Only supported on iOS.*
+  Future<bool> get isRestricted => status.isRestricted;
+
+  /// If the permission is in an unknown state.
+  Future<bool> get isUnknown => status.isUnknown;
+
+  /// If the user denied access to the requested feature and selected to never
+  /// again show a request for this permission.
+  /// *Only supported on Android.*
+  Future<bool> get isNeverAskedAgain => status.isNeverAskAgain;
+}
+
+/// Actions that apply only to permissions that have an associated service.
+extension ServicePermissionActions on ServicePermission {
+  /// The current status of the service associated with this permission.
+  ///
+  /// Notes about specific permissions:
+  /// - **[Permission.phone]**
+  ///   - Android:
+  ///     - The method will return [ServiceStatus.notApplicable] when:
+  ///       1. the device lacks the TELEPHONY feature
+  ///       2. TelephonyManager.getPhoneType() returns PHONE_TYPE_NONE
+  ///       3. when no Intents can be resolved to handle the `tel:` scheme
+  ///     - The method will return [ServiceStatus.disabled] when:
+  ///       1. the SIM card is missing
+  ///   - iOS:
+  ///     - The method will return [ServiceStatus.notApplicable] when:
+  ///       1. the native code can not find a handler for the `tel:` scheme
+  ///     - The method will return [ServiceStatus.disabled] when:
+  ///       1. the mobile network code (MNC) is either 0 or 65535. See
+  ///          https://stackoverflow.com/a/11595365 for details
+  ///   - **PLEASE NOTE that this is still not a perfect indication** of the
+  ///     devices' capability to place & connect phone calls
+  ///     as it also depends on the network condition.
+  Future<ServiceStatus> get serviceStatus => _handler.checkServiceStatus(this);
+}
 
 
-    return PermissionHandlerPlatform.instance
-        .shouldShowRequestPermissionRationale(permission);
+/// Actions that can be taken on a [List] of [Permission]s.
+extension PermissionListActions on List<Permission> {
+  /// Request the user for access to this list of permissions.
+  ///
+  /// Returns a [Map] containing the [PermissionStatus] per requested
+  /// [Permission].
+  Future<Map<Permission, PermissionStatus>> request() {
+    return _handler.requestPermissions(this);
   }
   }
 }
 }