Add metadatabase URL override for CloudKit sync

Sources/SQLiteData/CloudKit/Internal/Metadatabase.swift

@@ -13,10 +13,12 @@
       open "\(url.path(percentEncoded: false))"
       """
     )
-    try FileManager.default.createDirectory(
-      at: .applicationSupportDirectory,
-      withIntermediateDirectories: true
-    )
+    if !url.isInMemory {
+      try FileManager.default.createDirectory(
+        at: url.deletingLastPathComponent(),
+        withIntermediateDirectories: true
+      )
+    }
 
     @Dependency(\.context) var context
     guard !url.isInMemory || context != .live

Sources/SQLiteData/CloudKit/SyncEngine.swift

@@ -75,6 +75,8 @@
     ///     you do not want to be shareable with other users.
     ///   - containerIdentifier: The container identifier in CloudKit to synchronize to. If omitted
     ///     the container will be determined from the entitlements of your app.
+    ///   - metadatabaseURL: The location of the metadata database used to track CloudKit sync
+    ///     state. If omitted, a default location is derived from the main database path.
     ///   - defaultZone: The zone for all records to be stored in.
     ///   - startImmediately: Determines if the sync engine starts right away or requires an
     ///     explicit call to ``start()``. By default this argument is `true`.
@@ -90,6 +92,7 @@
       tables: repeat (each T1).Type,
       privateTables: repeat (each T2).Type,
       containerIdentifier: String? = nil,
+      metadatabaseURL: URL? = nil,
       defaultZone: CKRecordZone = CKRecordZone(zoneName: "co.pointfree.SQLiteData.defaultZone"),
       startImmediately: Bool? = nil,
       delegate: (any SyncEngineDelegate)? = nil,
@@ -146,6 +149,7 @@
             )
           },
           userDatabase: userDatabase,
+          metadatabaseURL: metadatabaseURL,
           logger: logger,
           delegate: delegate,
           tables: allTables,
@@ -195,6 +199,7 @@
           )
         },
         userDatabase: userDatabase,
+        metadatabaseURL: metadatabaseURL,
         logger: logger,
         delegate: delegate,
         tables: allTables,
@@ -215,6 +220,7 @@
           SyncEngine
         ) -> (private: any SyncEngineProtocol, shared: any SyncEngineProtocol),
       userDatabase: UserDatabase,
+      metadatabaseURL: URL? = nil,
       logger: Logger,
       delegate: (any SyncEngineDelegate)?,
       tables: [any SynchronizableTable],
@@ -258,12 +264,15 @@
       self.defaultSyncEngines = defaultSyncEngines
       self.userDatabase = userDatabase
       self.logger = logger
-      self.metadatabase = try defaultMetadatabase(
-        logger: logger,
-        url: try URL.metadatabase(
+      let resolvedMetadatabaseURL =
+        try metadatabaseURL
+        ?? URL.metadatabase(
           databasePath: userDatabase.path,
           containerIdentifier: container.containerIdentifier
         )
+      self.metadatabase = try defaultMetadatabase(
+        logger: logger,
+        url: resolvedMetadatabaseURL
       )
       self.tablesByName = Dictionary(
         uniqueKeysWithValues: self.tables.map { ($0.base.tableName, $0) }
@@ -2211,9 +2220,15 @@
     ///
     /// See <doc:PreparingDatabase> for more information on preparing your database.
     ///
-    /// - Parameter containerIdentifier: The identifier of the CloudKit container used to
-    /// synchronize data. Defaults to the value set in the app's entitlements.
-    public func attachMetadatabase(containerIdentifier: String? = nil) throws {
+    /// - Parameters:
+    ///   - containerIdentifier: The identifier of the CloudKit container used to
+    ///     synchronize data. Defaults to the value set in the app's entitlements.
+    ///   - metadatabaseURL: The location of the attached metadata database. If omitted, a default
+    ///     location is derived from the main database path.
+    public func attachMetadatabase(
+      containerIdentifier: String? = nil,
+      metadatabaseURL: URL? = nil
+    ) throws {
       @Dependency(\.context) var context
       let containerIdentifier =
         containerIdentifier
@@ -2234,15 +2249,18 @@
             """
         )
       }
-      let url = try URL.metadatabase(
-        databasePath: databasePath,
-        containerIdentifier: containerIdentifier
-      )
+      let url = try metadatabaseURL
+        ?? URL.metadatabase(
+          databasePath: databasePath,
+          containerIdentifier: containerIdentifier
+        )
       let path = url.isInMemory ? url.absoluteString : url.path(percentEncoded: false)
-      try FileManager.default.createDirectory(
-        at: .applicationSupportDirectory,
-        withIntermediateDirectories: true
-      )
+      if !url.isInMemory {
+        try FileManager.default.createDirectory(
+          at: url.deletingLastPathComponent(),
+          withIntermediateDirectories: true
+        )
+      }
       let database: any DatabaseWriter =
         url.isInMemory
         ? try DatabaseQueue(path: path)