[local_auth] Add platform interface to prepare for migration to federated architecture

packages/local_auth/local_auth_platform_interface/AUTHORS

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+# Below is a list of people and organizations that have contributed
+# to the Flutter project. Names should be added to the list like so:
+#
+#   Name/Organization <email address>
+
+Google Inc.
+The Chromium Authors
+German Saprykin <[email protected]>
+Benjamin Sauer <[email protected]>
+[email protected]
+Ali Bitek <[email protected]>
+Pol Batlló <[email protected]>
+Anatoly Pulyaevskiy
+Hayden Flinner <[email protected]>
+Stefano Rodriguez <[email protected]>
+Salvatore Giordano <[email protected]>
+Brian Armstrong <[email protected]>
+Paul DeMarco <[email protected]>
+Fabricio Nogueira <[email protected]>
+Simon Lightfoot <[email protected]>
+Ashton Thomas <[email protected]>
+Thomas Danner <[email protected]>
+Diego Velásquez <[email protected]>
+Hajime Nakamura <[email protected]>
+Tuyển Vũ Xuân <[email protected]>
+Miguel Ruivo <[email protected]>
+Sarthak Verma <[email protected]>
+Mike Diarmid <[email protected]>
+Invertase <[email protected]>
+Elliot Hesp <[email protected]>
+Vince Varga <[email protected]>
+Aawaz Gyawali <[email protected]>
+EUI Limited <[email protected]>
+Katarina Sheremet <[email protected]>
+Thomas Stockx <[email protected]>
+Sarbagya Dhaubanjar <[email protected]>
+Ozkan Eksi <[email protected]>
+Rishab Nayak <[email protected]>
+ko2ic <[email protected]>
+Jonathan Younger <[email protected]>
+Jose Sanchez <[email protected]>
+Debkanchan Samadder <[email protected]>
+Audrius Karosevicius <[email protected]>
+Lukasz Piliszczuk <[email protected]>
+SoundReply Solutions GmbH <[email protected]>
+Rafal Wachol <[email protected]>
+Pau Picas <[email protected]>
+Christian Weder <[email protected]>
+Alexandru Tuca <[email protected]>
+Christian Weder <[email protected]>
+Rhodes Davis Jr. <[email protected]>
+Luigi Agosti <[email protected]>
+Quentin Le Guennec <[email protected]>
+Koushik Ravikumar <[email protected]>
+Nissim Dsilva <[email protected]>
+Giancarlo Rocha <[email protected]>
+Ryo Miyake <[email protected]>
+Théo Champion <[email protected]>
+Kazuki Yamaguchi <[email protected]>
+Eitan Schwartz <[email protected]>
+Chris Rutkowski <[email protected]>
+Juan Alvarez <[email protected]>
+Aleksandr Yurkovskiy <[email protected]>
+Anton Borries <[email protected]>
+Alex Li <[email protected]>
+Rahul Raj <[email protected]>
+Bodhi Mulders <[email protected]>

packages/local_auth/local_auth_platform_interface/CHANGELOG.md

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+## 1.0.0
+
+* Initial release.

packages/local_auth/local_auth_platform_interface/LICENSE

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+Copyright 2013 The Flutter Authors. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without modification,
+are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials provided
+      with the distribution.
+    * Neither the name of Google Inc. nor the names of its
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

packages/local_auth/local_auth_platform_interface/README.md

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+# local_auth_platform_interface
+
+A common platform interface for the [`local_auth`][1] plugin.
+
+This interface allows platform-specific implementations of the `local_auth`
+plugin, as well as the plugin itself, to ensure they are supporting the
+same interface.
+
+# Usage
+
+To implement a new platform-specific implementation of `local_auth`, extend
+[`LocalAuthPlatform`][2] with an implementation that performs the
+platform-specific behavior, and when you register your plugin, set the default
+`LocalAuthPlatform` by calling
+`LocalAuthPlatform.instance = MyLocalAuthPlatform()`.
+
+# Note on breaking changes
+
+Strongly prefer non-breaking changes (such as adding a method to the interface)
+over breaking changes for this package.
+
+See https://flutter.dev/go/platform-interface-breaking-changes for a discussion
+on why a less-clean interface is preferable to a breaking change.
+
+[1]: ../local_auth
+[2]: lib/local_auth_platform_interface.dart

packages/local_auth/local_auth_platform_interface/lib/default_method_channel_platform.dart

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+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter/services.dart';
+import 'package:local_auth_platform_interface/local_auth_platform_interface.dart';
+import 'package:local_auth_platform_interface/types/auth_messages.dart';
+import 'package:local_auth_platform_interface/types/auth_options.dart';
+import 'package:local_auth_platform_interface/types/biometric_type.dart';
+
+const MethodChannel _channel = MethodChannel('plugins.flutter.io/local_auth');
+
+/// The default interface implementation acting as a placeholder for
+/// the native implementation to be set.
+///
+/// This implementation is not used by any of the implementations in this
+/// repository, and exists only for backward compatibility with any
+/// clients that were relying on internal details of the method channel
+/// in the pre-federated plugin.
+class DefaultLocalAuthPlatform extends LocalAuthPlatform {
+  @override
+  Future<bool> authenticate({
+    required String localizedReason,
+    required Iterable<AuthMessages> authMessages,
+    AuthenticationOptions options = const AuthenticationOptions(),
+  }) async {
+    assert(localizedReason.isNotEmpty);
+    final Map<String, Object> args = <String, Object>{
+      'localizedReason': localizedReason,
+      'useErrorDialogs': options.useErrorDialogs,
+      'stickyAuth': options.stickyAuth,
+      'sensitiveTransaction': options.sensitiveTransaction,
+      'biometricOnly': options.biometricOnly,
+    };
+    for (final AuthMessages messages in authMessages) {
+      args.addAll(messages.args);
+    }
+    return (await _channel.invokeMethod<bool>('authenticate', args)) ?? false;
+  }
+
+  @override
+  Future<List<BiometricType>> getEnrolledBiometrics() async {
+    final List<String> result = (await _channel.invokeListMethod<String>(
+          'getAvailableBiometrics',
+        )) ??
+        <String>[];
+    final List<BiometricType> biometrics = <BiometricType>[];
+    for (final String value in result) {
+      switch (value) {
+        case 'face':
+          biometrics.add(BiometricType.face);
+          break;
+        case 'fingerprint':
+          biometrics.add(BiometricType.fingerprint);
+          break;
+        case 'iris':
+          biometrics.add(BiometricType.iris);
+          break;
+        case 'undefined':
+          break;
+      }
+    }
+    return biometrics;
+  }
+
+  @override
+  Future<bool> deviceSupportsBiometrics() async {
+    return (await getEnrolledBiometrics()).isNotEmpty;
+  }
+
+  @override
+  Future<bool> isDeviceSupported() async =>
+      (await _channel.invokeMethod<bool>('isDeviceSupported')) ?? false;
+
+  @override
+  Future<bool> stopAuthentication() async =>
+      await _channel.invokeMethod<bool>('stopAuthentication') ?? false;
+}

packages/local_auth/local_auth_platform_interface/lib/local_auth_platform_interface.dart

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+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:local_auth_platform_interface/default_method_channel_platform.dart';
+import 'package:local_auth_platform_interface/types/auth_messages.dart';
+import 'package:local_auth_platform_interface/types/auth_options.dart';
+import 'package:local_auth_platform_interface/types/biometric_type.dart';
+import 'package:plugin_platform_interface/plugin_platform_interface.dart';
+
+/// The interface that implementations of local_auth must implement.
+///
+/// Platform implementations should extend this class rather than implement it as `local_auth`
+/// does not consider newly added methods to be breaking changes. Extending this class
+/// (using `extends`) ensures that the subclass will get the default implementation, while
+/// platform implementations that `implements` this interface will be broken by newly added
+/// [LocalAuthPlatform] methods.
+abstract class LocalAuthPlatform extends PlatformInterface {
+  /// Constructs a LocalAuthPlatform.
+  LocalAuthPlatform() : super(token: _token);
+
+  static final Object _token = Object();
+
+  static LocalAuthPlatform _instance = DefaultLocalAuthPlatform();
+
+  /// The default instance of [LocalAuthPlatform] to use.
+  ///
+  /// Defaults to [DefaultLocalAuthPlatform].
+  static LocalAuthPlatform get instance => _instance;
+
+  /// Platform-specific implementations should set this with their own
+  /// platform-specific class that extends [LocalAuthPlatform] when they
+  /// register themselves.
+  static set instance(LocalAuthPlatform instance) {
+    PlatformInterface.verifyToken(instance, _token);
+    _instance = instance;
+  }
+
+  /// Authenticates the user with biometrics available on the device while also
+  /// allowing the user to use device authentication - pin, pattern, passcode.
+  ///
+  /// Returns true if the user successfully authenticated, false otherwise.
+  ///
+  /// [localizedReason] is the message to show to user while prompting them
+  /// for authentication. This is typically along the lines of: 'Please scan
+  /// your finger to access MyApp.'. This must not be empty.
+  ///
+  /// Provide [authMessages] if you want to
+  /// customize messages in the dialogs.
+  ///
+  /// Provide [options] for configuring further authentication related options.
+  ///
+  /// Throws a [PlatformException] if there were technical problems with local
+  /// authentication (e.g. lack of relevant hardware). This might throw
+  /// [PlatformException] with error code [otherOperatingSystem] on the iOS
+  /// simulator.
+  Future<bool> authenticate({
+    required String localizedReason,
+    required Iterable<AuthMessages> authMessages,
+    AuthenticationOptions options = const AuthenticationOptions(),
+  }) async {
+    throw UnimplementedError('authenticate() has not been implemented.');
+  }
+
+  /// Returns true if the device is capable of checking biometrics.
+  ///
+  /// This will return true even if there are no biometrics currently enrolled.
+  Future<bool> deviceSupportsBiometrics() async {
+    throw UnimplementedError('canCheckBiometrics() has not been implemented.');
+  }
+
+  /// Returns a list of enrolled biometrics.
+  ///
+  /// Possible values include:
+  /// - BiometricType.face
+  /// - BiometricType.fingerprint
+  /// - BiometricType.iris (not yet implemented)
+  /// - BiometricType.strong
+  /// - BiometricType.weak
+  Future<List<BiometricType>> getEnrolledBiometrics() async {
+    throw UnimplementedError(
+        'getAvailableBiometrics() has not been implemented.');
+  }
+
+  /// Returns true if device is capable of checking biometrics or is able to
+  /// fail over to device credentials.
+  Future<bool> isDeviceSupported() async {
+    throw UnimplementedError('isDeviceSupported() has not been implemented.');
+  }
+
+  /// Cancels any authentication currently in progress.
+  ///
+  /// Returns true if auth was cancelled successfully.
+  /// Returns false if there was no authentication in progress,
+  /// or an error occurred.
+  Future<bool> stopAuthentication() async {
+    throw UnimplementedError('stopAuthentication() has not been implemented.');
+  }
+}

packages/local_auth/local_auth_platform_interface/lib/types/auth_messages.dart

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+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+/// Abstract class for storing platform specific strings.
+abstract class AuthMessages {
+  /// Constructs an instance of [AuthMessages].
+  const AuthMessages();
+
+  /// Returns all platform-specific messages as a map.
+  Map<String, String> get args;
+}

packages/local_auth/local_auth_platform_interface/lib/types/auth_options.dart

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+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter/foundation.dart';
+
+/// Options wrapper for [LocalAuthPlatform.authenticate] parameters.
+@immutable
+class AuthenticationOptions {
+  /// Constructs a new instance.
+  const AuthenticationOptions({
+    this.useErrorDialogs = true,
+    this.stickyAuth = false,
+    this.sensitiveTransaction = true,
+    this.biometricOnly = false,
+  });
+
+  /// Whether the system will attempt to handle user-fixable issues encountered
+  /// while authenticating. For instance, if a fingerprint reader exists on the
+  /// device but there's no fingerprint registered, the plugin might attempt to
+  /// take the user to settings to add one. Anything that is not user fixable,
+  /// such as no biometric sensor on device, will still result in
+  /// a [PlatformException].
+  final bool useErrorDialogs;
+
+  /// Used when the application goes into background for any reason while the
+  /// authentication is in progress. Due to security reasons, the
+  /// authentication has to be stopped at that time. If stickyAuth is set to
+  /// true, authentication resumes when the app is resumed. If it is set to
+  /// false (default), then as soon as app is paused a failure message is sent
+  /// back to Dart and it is up to the client app to restart authentication or
+  /// do something else.
+  final bool stickyAuth;
+
+  /// Whether platform specific precautions are enabled. For instance, on face
+  /// unlock, Android opens a confirmation dialog after the face is recognized
+  /// to make sure the user meant to unlock their device.
+  final bool sensitiveTransaction;
+
+  /// Prevent authentications from using non-biometric local authentication
+  /// such as pin, passcode, or pattern.
+  final bool biometricOnly;
+
+  @override
+  bool operator ==(Object other) =>
+      identical(this, other) ||
+      other is AuthenticationOptions &&
+          runtimeType == other.runtimeType &&
+          useErrorDialogs == other.useErrorDialogs &&
+          stickyAuth == other.stickyAuth &&
+          sensitiveTransaction == other.sensitiveTransaction &&
+          biometricOnly == other.biometricOnly;
+
+  @override
+  int get hashCode =>
+      useErrorDialogs.hashCode ^
+      stickyAuth.hashCode ^
+      sensitiveTransaction.hashCode ^
+      biometricOnly.hashCode;
+}