Perform crypto migration if necessary

MatrixSDK/Background/MXBackgroundSyncService.swift

@@ -83,7 +83,7 @@ public enum MXBackgroundSyncServiceError: Error {
 
         crypto = {
             #if DEBUG
-            if MXSDKOptions.sharedInstance().enableCryptoV2 {
+            if MXSDKOptions.sharedInstance().isCryptoSDKAvailable && MXSDKOptions.sharedInstance().enableCryptoSDK {
                 // Crypto V2 is currently unable to decrypt notifications due to single-process store,
                 // so it uses dummy background crypto that does not do anything.
                 return MXDummyBackgroundCrypto()

MatrixSDK/Crypto/CryptoMachine/MXCryptoMachine.swift

@@ -94,16 +94,18 @@ class MXCryptoMachine {
             try await requests.queryKeys(users: users)
         }
         self.getRoomAction = getRoomAction
-    }
-
-    func start() async throws {
+
         let details = """
-        Starting the crypto machine for \(userId)
+        Initialized the crypto machine for \(userId)
           - device id  : \(deviceId)
           - ed25519    : \(deviceEd25519Key ?? "")
           - curve25519 : \(deviceCurve25519Key ?? "")
         """
         log.debug(details)
+    }
+
+    func uploadKeysIfNecessary() async throws {
+        log.debug("Checking for keys to upload")
 
         var keysUploadRequest: Request?
         for request in try machine.outgoingRequests() {
@@ -120,7 +122,6 @@ class MXCryptoMachine {
         }
 
         try await handleRequest(request)
-
         log.debug("Keys successfully uploaded")
     }
 

MatrixSDK/Crypto/MXCrypto.m

@@ -158,7 +158,7 @@ @implementation MXLegacyCrypto
 #ifdef MX_CRYPTO
 
     #if DEBUG
-    if (MXSDKOptions.sharedInstance.enableCryptoV2)
+    if (MXSDKOptions.sharedInstance.isCryptoSDKAvailable && MXSDKOptions.sharedInstance.enableCryptoSDK)
     {
         return [self createCryptoV2WithSession:mxSession error:error];
     }
@@ -182,7 +182,7 @@ + (void)checkCryptoWithMatrixSession:(MXSession *)mxSession
 {
 #ifdef MX_CRYPTO
     #if DEBUG
-    if (MXSDKOptions.sharedInstance.enableCryptoV2)
+    if (MXSDKOptions.sharedInstance.isCryptoSDKAvailable && MXSDKOptions.sharedInstance.enableCryptoSDK)
     {
         NSError *error;
         id<MXCrypto> crypto = [self createCryptoV2WithSession:mxSession error:&error];

MatrixSDK/Crypto/MXCryptoV2.swift

@@ -203,7 +203,9 @@ private class MXCryptoV2: NSObject, MXCrypto {
         log.debug("->")
         startTask = Task {
             do {
-                try await machine.start()
+                try migrateIfNecessary()
+
+                try await machine.uploadKeysIfNecessary()
                 crossSigning.refreshState(success: nil)
                 backup?.checkAndStart()
 
@@ -247,6 +249,20 @@ private class MXCryptoV2: NSObject, MXCrypto {
         }
     }
 
+    private func migrateIfNecessary() throws {
+        guard legacyStore.cryptoVersion.rawValue < MXCryptoVersion.versionLegacyDeprecated.rawValue else {
+            log.debug("Legacy crypto has already been deprecated, no need to migrate")
+            return
+        }
+
+        log.debug("Requires migration from legacy crypto")
+        let migration = MXCryptoMigrationV2(legacyStore: legacyStore)
+        try migration.migrateCrypto()
+
+        log.debug("Marking legacy crypto as deprecated")
+        legacyStore.cryptoVersion = MXCryptoVersion.versionLegacyDeprecated
+    }
+
     // MARK: - Event Encryption
 
     public func isRoomEncrypted(_ roomId: String) -> Bool {

MatrixSDK/Crypto/Migration/MXCryptoVersion.h

@@ -32,8 +32,13 @@ typedef NS_ENUM(NSInteger, MXCryptoVersion)
     // https://github.com/vector-im/element-ios/issues/3818
     MXCryptoVersion2,
 
-    // Keep it at the last position. It is used to compute MXCryptoVersionLast.
+    // Keep it at the last position of valid versions, except for the deprecated variant.
+    // It is used to compute MXCryptoVersionLast.
     MXCryptoVersionCount,
+
+    // The internal crypto module has been deprecated in favour of `MatrixCryptoSDK`
+    // The value is set manually to leave room for intermediate version 3, 4 ...
+    MXCryptoVersionLegacyDeprecated = 1000,
 };
 
 // The current version of MXCrypto

MatrixSDK/MXSDKOptions.h

@@ -34,7 +34,6 @@ typedef NS_ENUM(NSUInteger, MXCallTransferType)
     MXCallTransferTypeLocal
 };
 
-
 #pragma mark - Build time options
 
 /**
@@ -207,12 +206,23 @@ NS_ASSUME_NONNULL_BEGIN
 #if DEBUG
 
 /**
- Enable Crypto module V2, a work-in-progress and NOT production-ready implementation
- of [matrix-rust-sdk](https://github.com/matrix-org/matrix-rust-sdk/tree/main/crates/matrix-sdk-crypto).
+ 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.
+ 
+ To control which crypto module is actually used, set `enableCryptoSDK`.
+ 
+ @remark NO by default.
+ */
+@property (nonatomic) BOOL isCryptoSDKAvailable;
+
+/**
+ 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.
  */
-@property (nonatomic) BOOL enableCryptoV2;
+@property (nonatomic) BOOL enableCryptoSDK;
 
 #endif
 

MatrixSDK/MXSDKOptions.m

@@ -56,7 +56,8 @@ - (instancetype)init
         _enableRoomSharedHistoryOnInvite = NO;
 
         #if DEBUG
-        _enableCryptoV2 = NO;
+        _isCryptoSDKAvailable = NO;
+        _enableCryptoSDK = NO;
         #endif
 
         _enableSymmetricBackup = NO;