Control CryptoSDK via feature flag

MatrixSDK.xcodeproj/project.pbxproj

@@ -2025,6 +2025,8 @@
 		EDC8C4092968A993003792C5 /* MXKeysQueryScheduler.swift in Sources */ = {isa = PBXBuildFile; fileRef = EDC8C4072968A993003792C5 /* MXKeysQueryScheduler.swift */; };
 		EDC8C40D2968C37E003792C5 /* MXKeysQuerySchedulerUnitTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = EDC8C40A2968A9F7003792C5 /* MXKeysQuerySchedulerUnitTests.swift */; };
 		EDC8C40E2968C37F003792C5 /* MXKeysQuerySchedulerUnitTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = EDC8C40A2968A9F7003792C5 /* MXKeysQuerySchedulerUnitTests.swift */; };
+		EDCAD251299BF7F40088B4DA /* MXCryptoV2Feature.swift in Sources */ = {isa = PBXBuildFile; fileRef = EDCAD250299BF7F40088B4DA /* MXCryptoV2Feature.swift */; };
+		EDCAD252299BF7F40088B4DA /* MXCryptoV2Feature.swift in Sources */ = {isa = PBXBuildFile; fileRef = EDCAD250299BF7F40088B4DA /* MXCryptoV2Feature.swift */; };
 		EDCB65E22912AB0C00F55D4D /* MXRoomEventDecryption.swift in Sources */ = {isa = PBXBuildFile; fileRef = EDCB65E12912AB0C00F55D4D /* MXRoomEventDecryption.swift */; };
 		EDCB65E32912AB0C00F55D4D /* MXRoomEventDecryption.swift in Sources */ = {isa = PBXBuildFile; fileRef = EDCB65E12912AB0C00F55D4D /* MXRoomEventDecryption.swift */; };
 		EDCF802D2941FF220059E774 /* MXCryptoMigrationV2.swift in Sources */ = {isa = PBXBuildFile; fileRef = EDCF802C2941FF220059E774 /* MXCryptoMigrationV2.swift */; };
@@ -3171,6 +3173,7 @@
 		EDC2A0E528369E740039F3D6 /* CryptoTests.xctestplan */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text; path = CryptoTests.xctestplan; sourceTree = "<group>"; };
 		EDC8C4072968A993003792C5 /* MXKeysQueryScheduler.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MXKeysQueryScheduler.swift; sourceTree = "<group>"; };
 		EDC8C40A2968A9F7003792C5 /* MXKeysQuerySchedulerUnitTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MXKeysQuerySchedulerUnitTests.swift; sourceTree = "<group>"; };
+		EDCAD250299BF7F40088B4DA /* MXCryptoV2Feature.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MXCryptoV2Feature.swift; sourceTree = "<group>"; };
 		EDCB65E12912AB0C00F55D4D /* MXRoomEventDecryption.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MXRoomEventDecryption.swift; sourceTree = "<group>"; };
 		EDCF802C2941FF220059E774 /* MXCryptoMigrationV2.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MXCryptoMigrationV2.swift; sourceTree = "<group>"; };
 		EDD4197D28DCAA5F007F3757 /* MXNativeKeyBackupEngine.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = MXNativeKeyBackupEngine.h; sourceTree = "<group>"; };
@@ -3525,6 +3528,7 @@
 				322A51B41D9AB15900C8536D /* MXCrypto.h */,
 				322A51B51D9AB15900C8536D /* MXCrypto.m */,
 				ED47CB6C28523995004FD755 /* MXCryptoV2.swift */,
+				EDCAD250299BF7F40088B4DA /* MXCryptoV2Feature.swift */,
 				ED5EF151297AB33E00A5ADDA /* MXCryptoV2Factory.swift */,
 				325D1C251DFECE0D0070B8BF /* MXCrypto_Private.h */,
 				322A51C51D9BBD3C00C8536D /* MXOlmDevice.h */,
@@ -7142,6 +7146,7 @@
 				EC2EACFF266625170038B61F /* MXRoomLastMessage.m in Sources */,
 				EDF1B6902876CD2C00BBBCEE /* MXTaskQueue.swift in Sources */,
 				EC8A539525B1BC77004E0802 /* MXUserModel.m in Sources */,
+				EDCAD251299BF7F40088B4DA /* MXCryptoV2Feature.swift in Sources */,
 				ED5EF14F297AB29F00A5ADDA /* MXEventDecryptionResult+DecryptedEvent.swift in Sources */,
 				3252DCAF224BE5D40032264F /* MXKeyVerificationManager.m in Sources */,
 				323E0C5C1A306D7A00A31D73 /* MXEvent.m in Sources */,
@@ -7809,6 +7814,7 @@
 				EC8A53D925B1BCC6004E0802 /* MXThirdPartyProtocolInstance.m in Sources */,
 				EDF1B6912876CD2C00BBBCEE /* MXTaskQueue.swift in Sources */,
 				B14EF2422397E90400758AF0 /* MXDeviceInfo.m in Sources */,
+				EDCAD252299BF7F40088B4DA /* MXCryptoV2Feature.swift in Sources */,
 				ED5EF150297AB29F00A5ADDA /* MXEventDecryptionResult+DecryptedEvent.swift in Sources */,
 				B14EF2432397E90400758AF0 /* MXIncomingSASTransaction.m in Sources */,
 				B14EF2442397E90400758AF0 /* NSObject+sortedKeys.m in Sources */,

MatrixSDK/Background/MXBackgroundSyncService.swift

@@ -65,7 +65,12 @@ public enum MXBackgroundSyncServiceError: Error {
 
     /// Initializer
     /// - Parameter credentials: account credentials
-    public init(withCredentials credentials: MXCredentials, persistTokenDataHandler: MXRestClientPersistTokenDataHandler? = nil, unauthenticatedHandler: MXRestClientUnauthenticatedHandler? = nil) {
+    public init(
+        withCredentials credentials: MXCredentials,
+        isCryptoSDKEnabled: Bool = false,
+        persistTokenDataHandler: MXRestClientPersistTokenDataHandler? = nil,
+        unauthenticatedHandler: MXRestClientUnauthenticatedHandler? = nil
+    ) {
         processingQueue = DispatchQueue(label: "MXBackgroundSyncServiceQueue-" + MXTools.generateSecret())
         self.credentials = credentials
 
@@ -88,14 +93,13 @@ public enum MXBackgroundSyncServiceError: Error {
         // We can flush any crypto data if our sync response store is empty
         let resetBackgroundCryptoStore = syncResponseStoreManager.syncToken() == nil
 
-        crypto = {
-            if MXSDKOptions.sharedInstance().isCryptoSDKAvailable && MXSDKOptions.sharedInstance().enableCryptoSDK {
-                return MXBackgroundCryptoV2(credentials: credentials, restClient: restClient)
-            }
-
-            MXLog.debug("[MXBackgroundSyncService] init: constructing legacy crypto \(MXSDKOptions.sharedInstance().isCryptoSDKAvailable) \(MXSDKOptions.sharedInstance().enableCryptoSDK)")
-            return MXLegacyBackgroundCrypto(credentials: credentials, resetBackgroundCryptoStore: resetBackgroundCryptoStore)
-        }()
+        if isCryptoSDKEnabled {
+            MXLog.debug("[MXBackgroundSyncService] init: constructing crypto v2")
+            crypto = MXBackgroundCryptoV2(credentials: credentials, restClient: restClient)
+        } else {
+            MXLog.debug("[MXBackgroundSyncService] init: constructing legacy crypto")
+            crypto = MXLegacyBackgroundCrypto(credentials: credentials, resetBackgroundCryptoStore: resetBackgroundCryptoStore)
+        }
 
         pushRulesManager = MXBackgroundPushRulesManager(withCredentials: credentials)
         MXLog.debug("[MXBackgroundSyncService] init complete")

MatrixSDK/Crypto/MXCrypto.m

@@ -150,25 +150,13 @@ @implementation MXLegacyCrypto
 @synthesize keyVerificationManager = _keyVerificationManager;
 @synthesize recoveryService = _recoveryService;
 
-+ (MXCryptoV2Factory *)sharedCryptoV2Factory
-{
-    static MXCryptoV2Factory *factory = nil;
-    static dispatch_once_t onceToken;
-
-    dispatch_once(&onceToken, ^{
-        factory = [[MXCryptoV2Factory alloc] init];
-    });
-
-    return factory;
-}
-
 + (id<MXCrypto>)createCryptoWithMatrixSession:(MXSession *)mxSession
                                         error:(NSError **)error
 {
     __block id<MXCrypto> crypto;
 
 #ifdef MX_CRYPTO
-    if (MXSDKOptions.sharedInstance.isCryptoSDKAvailable && MXSDKOptions.sharedInstance.enableCryptoSDK)
+    if (MXSDKOptions.sharedInstance.enableCryptoSDK)
     {
         MXLogFailure(@"[MXCrypto] createCryptoWithMatrixSession: Crypto V2 should not be created directly, use initializeCryptoWithMatrixSession instead");
         return nil;
@@ -192,15 +180,19 @@ + (void)initializeCryptoWithMatrixSession:(MXSession *)mxSession
                                  complete:(void (^)(id<MXCrypto> crypto, NSError *error))complete
 {
 #ifdef MX_CRYPTO
-    if (MXSDKOptions.sharedInstance.isCryptoSDKAvailable && MXSDKOptions.sharedInstance.enableCryptoSDK)
-    {
-        MXCryptoV2Factory *factory = [MXLegacyCrypto sharedCryptoV2Factory];
-        [factory buildCryptoWithSession:mxSession migrationProgress:migrationProgress
-                                success:^(id<MXCrypto> crypto) {
-                                    complete(crypto, nil);
-                                } failure:^(NSError *error) {
-                                    complete(nil, error);
-                                }];
+
+    // Each time we construct the crypto module (app launch, login etc) we have a chance to try to enable
+    // the newer SDK crypto module, if it is available for this particular user.
+    [MXSDKOptions.sharedInstance.cryptoSDKFeature enableIfAvailableForUserId:mxSession.myUserId];
+    if (MXSDKOptions.sharedInstance.enableCryptoSDK)
+    {
+        [MXCryptoV2Factory.shared buildCryptoWithSession:mxSession
+                                       migrationProgress:migrationProgress
+                                                 success:^(id<MXCrypto> crypto) {
+                                                    complete(crypto, nil); }
+                                                 failure:^(NSError *error) {
+                                                    complete(nil, error);
+                                                 }];
         return;
     }
 

MatrixSDK/Crypto/MXCryptoV2Factory.swift

@@ -22,6 +22,7 @@ import Foundation
         case storeNotAvailable
     }
 
+    @objc public static let shared = MXCryptoV2Factory()
     private let log = MXNamedLog(name: "MXCryptoV2Factory")
 
     @objc public func buildCrypto(

MatrixSDK/Crypto/MXCryptoV2Feature.swift

@@ -0,0 +1,45 @@
+// 
+// Copyright 2023 The Matrix.org Foundation C.I.C
+//
+// 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.
+//
+
+import Foundation
+
+/// Feature representing the availability of the external rust-based Crypto SDK
+/// whilst it is not fully available to everyone and / or is an optional feature.
+@objc public protocol MXCryptoV2Feature {
+
+    /// Is Crypto SDK currently enabled
+    ///
+    /// By default this value is `false`. Once enabled, it can only be disabled by logging out,
+    /// as there is no way to migrate from from Crypto SDK back to legacy crypto.
+    var isEnabled: Bool { get }
+
+    /// Manually enable the feature
+    ///
+    /// This is typically triggered by some user settings / Labs as an experimental feature. Once called
+    /// it should restart the session to re-initialize the crypto module.
+    func enable()
+
+    /// Try to enable the feature for a given user
+    ///
+    /// This method should only be called when initializing a crypto module (e.g. during app launch or login),
+    /// as it is not possible to swap out crypto modules whilst a session is active.
+    ///
+    /// The availability conditions are implementation details, typically consisting of
+    /// various feature flags.
+    ///
+    /// If available, this method will set `isEnabled` permanently to `true`.
+    func enableIfAvailable(forUserId userId: String!)
+}

MatrixSDK/MXSDKOptions.h

@@ -48,7 +48,7 @@ typedef NS_ENUM(NSUInteger, MXCallTransferType)
 
 NS_ASSUME_NONNULL_BEGIN
 
-@protocol MXBackgroundModeHandler;
+@protocol MXBackgroundModeHandler, MXCryptoV2Feature;
 
 /**
  SDK options that can be set at the launch time.
@@ -204,23 +204,18 @@ NS_ASSUME_NONNULL_BEGIN
 @property (nonatomic) BOOL enableRoomSharedHistoryOnInvite;
 
 /**
- The state of the rust-based `MatrixCryptoSDK` which replaces `MatrixSDK`'s internal crypto module,
- and whether it is available to a user as an option.
+ An object which controls the availabilty of the rust-based `MatrixCryptoSDK`.
  
- To control which crypto module is actually used, set `enableCryptoSDK`.
- 
- @remark NO by default.
+ @remark nil by default.
  */
-@property (nonatomic) BOOL isCryptoSDKAvailable;
+@property (nonatomic, nullable) id<MXCryptoV2Feature> cryptoSDKFeature;
 
 /**
  Use the rust-based `MatrixCryptoSDK` instead of `MatrixSDK`'s internal crypto module.
  
- This option should only be enabled if `isCryptoSDKAvailable` is set to YES.
- 
- @remark NO by default.
+ @remark this property is a convenience getter for `cryptoSDKFeature.isEnabled`
  */
-@property (nonatomic) BOOL enableCryptoSDK;
+@property (nonatomic, readonly) BOOL enableCryptoSDK;
 
 /**
  Enable symmetric room key backups
@@ -240,9 +235,9 @@ NS_ASSUME_NONNULL_BEGIN
  Enable the calculating of progress during session startup, incl counting the number
  of attempts to sync with the server and percentage of response data processed.
  
- @remark NO by default
+ @remark the value currently depends on `enableCryptoSDK` being `YES`
  */
-@property (nonatomic) BOOL enableStartupProgress;
+@property (nonatomic, readonly) BOOL enableStartupProgress;
 
 @end
 

MatrixSDK/MXSDKOptions.m

@@ -54,18 +54,31 @@ - (instancetype)init
         _authEnableRefreshTokens = NO;
         _enableThreads = NO;
         _enableRoomSharedHistoryOnInvite = NO;
-
-        _isCryptoSDKAvailable = YES;
-        _enableCryptoSDK = NO;
-
         _enableSymmetricBackup = NO;
         _enableNewClientInformationFeature = NO;
-        _enableStartupProgress = NO;
     }
 
     return self;
 }
 
+- (BOOL)enableCryptoSDK
+{
+    if (!self.cryptoSDKFeature)
+    {
+        MXLogError(@"[MXSDKOptions] enableCryptoSDK: Crypto SDK feature is not configured");
+        return NO;
+    }
+    return self.cryptoSDKFeature.isEnabled;
+}
+
+- (BOOL)enableStartupProgress
+{
+    // The value of `enableStartupProgress` depends on `enableCryptoSDK` as the latter provides some new UX elements
+    // such as initial data migration. It is a good opportunity to enable startup progress as well, before it becomes
+    // default to all.
+    return self.enableCryptoSDK;
+}
+
 - (void)setRoomListDataManagerClass:(Class)roomListDataManagerClass
 {
     // Sanity check

changelog.d/pr-1719.change

@@ -0,0 +1 @@
+CryptoV2: Control CryptoSDK via feature flag