Refactor Pbkdf2SecretKey Class

lib/src/impl_ffi/impl_ffi.dart

@@ -86,4 +86,7 @@ final class _WebCryptoImpl implements WebCryptoImpl {
 
   @override
   final hmacSecretKey = const _StaticHmacSecretKeyImpl();
+
+  @override
+  final pbkdf2SecretKey = const _StaticPbkdf2SecretKeyImpl();
 }

lib/src/impl_ffi/impl_ffi.pbkdf2.dart

@@ -16,14 +16,23 @@
 
 part of 'impl_ffi.dart';
 
-Future<Pbkdf2SecretKey> pbkdf2SecretKey_importRawKey(List<int> keyData) async {
-  return _Pbkdf2SecretKey(Uint8List.fromList(keyData));
+Future<Pbkdf2SecretKeyImpl> pbkdf2SecretKey_importRawKey(List<int> keyData) async {
+  return _Pbkdf2SecretKeyImpl(Uint8List.fromList(keyData));
 }
 
-class _Pbkdf2SecretKey implements Pbkdf2SecretKey {
+final class _StaticPbkdf2SecretKeyImpl implements StaticPbkdf2SecretKeyImpl {
+  const _StaticPbkdf2SecretKeyImpl();
+
+  @override
+  Future<Pbkdf2SecretKeyImpl> importRawKey(List<int> keyData) {
+    return pbkdf2SecretKey_importRawKey(keyData);
+  }
+}
+
+final class _Pbkdf2SecretKeyImpl implements Pbkdf2SecretKeyImpl {
   final Uint8List _key;
 
-  _Pbkdf2SecretKey(this._key);
+  _Pbkdf2SecretKeyImpl(this._key);
 
   @override
   String toString() {

lib/src/impl_interface/impl_interface.dart

@@ -23,6 +23,7 @@ import 'package:webcrypto/webcrypto.dart';
 part 'impl_interface.aescbc.dart';
 part 'impl_interface.aesctr.dart';
 part 'impl_interface.hmac.dart';
+part 'impl_interface.pbkdf2.dart';
 part 'impl_interface.aesgcm.dart';
 
 /// Interface to be provided by platform implementations.
@@ -46,4 +47,5 @@ abstract interface class WebCryptoImpl {
   StaticAesCtrSecretKeyImpl get aesCtrSecretKey;
   StaticAesGcmSecretKeyImpl get aesGcmSecretKey;
   StaticHmacSecretKeyImpl get hmacSecretKey;
+  StaticPbkdf2SecretKeyImpl get pbkdf2SecretKey;
 }

lib/src/impl_interface/impl_interface.pbkdf2.dart

@@ -0,0 +1,23 @@
+// Copyright 2020 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+part of 'impl_interface.dart';
+
+abstract interface class StaticPbkdf2SecretKeyImpl {
+  Future<Pbkdf2SecretKeyImpl> importRawKey(List<int> keyData);
+}
+
+abstract interface class Pbkdf2SecretKeyImpl {
+  Future<Uint8List> deriveBits(int length, Hash hash, List<int> salt, int iterations);
+}

lib/src/impl_js/impl_js.dart

@@ -72,4 +72,7 @@ final class _WebCryptoImpl implements WebCryptoImpl {
 
   @override
   final hmacSecretKey = const _StaticHmacSecretKeyImpl();
+
+  @override
+  final pbkdf2SecretKey = const _StaticPbkdf2SecretKeyImpl();
 }

lib/src/impl_js/impl_js.pbkdf2.dart

@@ -18,8 +18,8 @@ part of 'impl_js.dart';
 
 const _pbkdf2AlgorithmName = 'PBKDF2';
 
-Future<Pbkdf2SecretKey> pbkdf2SecretKey_importRawKey(List<int> keyData) async {
-  return _Pbkdf2SecretKey(await _importKey(
+Future<Pbkdf2SecretKeyImpl> pbkdf2SecretKey_importRawKey(List<int> keyData) async {
+  return _Pbkdf2SecretKeyImpl(await _importKey(
     'raw',
     keyData,
     const subtle.Algorithm(name: _pbkdf2AlgorithmName),
@@ -31,9 +31,18 @@ Future<Pbkdf2SecretKey> pbkdf2SecretKey_importRawKey(List<int> keyData) async {
   ));
 }
 
-class _Pbkdf2SecretKey implements Pbkdf2SecretKey {
+final class _StaticPbkdf2SecretKeyImpl implements StaticPbkdf2SecretKeyImpl {
+  const _StaticPbkdf2SecretKeyImpl();
+
+  @override
+  Future<Pbkdf2SecretKeyImpl> importRawKey(List<int> keyData) {
+    return pbkdf2SecretKey_importRawKey(keyData);
+  }
+}
+
+final class _Pbkdf2SecretKeyImpl implements Pbkdf2SecretKeyImpl {
   final subtle.JSCryptoKey _key;
-  _Pbkdf2SecretKey(this._key);
+  _Pbkdf2SecretKeyImpl(this._key);
 
   @override
   String toString() {

lib/src/impl_stub.dart

@@ -234,5 +234,3 @@ Future<HkdfSecretKey> hkdfSecretKey_importRawKey(List<int> keyData) =>
 
 //---------------------- PBKDF2
 
-Future<Pbkdf2SecretKey> pbkdf2SecretKey_importRawKey(List<int> keyData) =>
-    throw _notImplemented;

lib/src/impl_stub/impl_stub.dart

@@ -21,6 +21,7 @@ part 'impl_stub.aescbc.dart';
 part 'impl_stub.aesctr.dart';
 part 'impl_stub.aesgcm.dart';
 part 'impl_stub.hmac.dart';
+part 'impl_stub.pbkdf2.dart';
 
 const WebCryptoImpl webCryptImpl = _WebCryptoImpl();
 
@@ -38,4 +39,7 @@ final class _WebCryptoImpl implements WebCryptoImpl {
 
   @override
   final hmacSecretKey = const _StaticHmacSecretKeyImpl();
+
+  @override
+  final pbkdf2SecretKey = const _StaticPbkdf2SecretKeyImpl();
 }

lib/src/impl_stub/impl_stub.pbkdf2.dart

@@ -0,0 +1,24 @@
+// Copyright 2020 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+part of 'impl_stub.dart';
+
+final class _StaticPbkdf2SecretKeyImpl implements StaticPbkdf2SecretKeyImpl {
+  const _StaticPbkdf2SecretKeyImpl();
+
+  @override
+  Future<Pbkdf2SecretKeyImpl> importRawKey(List<int> keyData) {
+    throw UnimplementedError('Not implemented');
+  }
+}

lib/src/webcrypto/webcrypto.pbkdf2.dart

@@ -50,17 +50,20 @@ part of 'webcrypto.dart';
 ///
 /// [1]: https://tools.ietf.org/html/rfc8018
 // TODO: Rewrite all RFC links to use https://www.rfc-editor.org/rfc/rfcXXXX
-@sealed
-abstract class Pbkdf2SecretKey {
-  Pbkdf2SecretKey._(); // keep the constructor private.
+
+final class Pbkdf2SecretKey {
+  final Pbkdf2SecretKeyImpl _impl;
+
+  Pbkdf2SecretKey._(this._impl); // keep the constructor private.
 
   /// Import [Pbkdf2SecretKey] from raw [keyData].
   ///
   /// Creates a [Pbkdf2SecretKey] for key derivation using [keyData].
   ///
   /// {@macro Pbkdf2SecretKey:example}
-  static Future<Pbkdf2SecretKey> importRawKey(List<int> keyData) {
-    return impl.pbkdf2SecretKey_importRawKey(keyData);
+  static Future<Pbkdf2SecretKey> importRawKey(List<int> keyData) async {
+    final impl = await webCryptImpl.pbkdf2SecretKey.importRawKey(keyData);
+    return Pbkdf2SecretKey._(impl);
   }
 
   /// Derive key from [salt] and password specified as `keyData` in
@@ -90,5 +93,6 @@ abstract class Pbkdf2SecretKey {
     Hash hash,
     List<int> salt,
     int iterations,
-  );
+  ) =>
+    _impl.deriveBits(length, hash, salt, iterations);
 }