Use app group container

DB/Sources/DB/Content/ContentDatabase.swift

@@ -17,21 +17,19 @@ public struct ContentDatabase {
                 useHomeTimelineLastReadId: Bool,
                 useNotificationsLastReadId: Bool,
                 inMemory: Bool,
+                appGroup: String,
                 keychain: Keychain.Type) throws {
         if inMemory {
             databaseWriter = DatabaseQueue()
+            try Self.migrator.migrate(databaseWriter)
         } else {
-            let path = try Self.fileURL(id: id).path
+            databaseWriter = try DatabasePool.withFileCoordinator(
-            var configuration = Configuration()
+                url: Self.fileURL(id: id, appGroup: appGroup),
-
+                migrator: Self.migrator) {
-            configuration.prepareDatabase {
+                try Secrets.databaseKey(identityId: id, keychain: keychain)
-                try $0.usePassphrase(Secrets.databaseKey(identityId: id, keychain: keychain))
             }
-
-            databaseWriter = try DatabasePool(path: path, configuration: configuration)
         }
 
-        try Self.migrator.migrate(databaseWriter)
         try Self.clean(
             databaseWriter,
             useHomeTimelineLastReadId: useHomeTimelineLastReadId,
@@ -47,8 +45,8 @@ public struct ContentDatabase {
 }
 
 public extension ContentDatabase {
-    static func delete(id: Identity.Id) throws {
+    static func delete(id: Identity.Id, appGroup: String) throws {
-        try FileManager.default.removeItem(at: fileURL(id: id))
+        try FileManager.default.removeItem(at: fileURL(id: id, appGroup: appGroup))
     }
 
     func insert(status: Status) -> AnyPublisher<Never, Error> {
@@ -411,8 +409,8 @@ public extension ContentDatabase {
 
 private extension ContentDatabase {
     static let cleanAfterLastReadIdCount = 40
-    static func fileURL(id: Identity.Id) throws -> URL {
+    static func fileURL(id: Identity.Id, appGroup: String) throws -> URL {
-        try FileManager.default.databaseDirectoryURL(name: id.uuidString)
+        try FileManager.default.databaseDirectoryURL(name: id.uuidString, appGroup: appGroup)
     }
 
     // swiftlint:disable:next function_body_length

DB/Sources/DB/Extensions/DatabasePool+Extensions.swift

@@ -0,0 +1,51 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import Foundation
+import GRDB
+
+// https://github.com/groue/GRDB.swift/blob/master/Documentation/SharingADatabase.md
+
+extension DatabasePool {
+    class func withFileCoordinator(url: URL,
+                                   migrator: DatabaseMigrator,
+                                   passphrase: @escaping (() throws -> String)) throws -> Self {
+        let coordinator = NSFileCoordinator(filePresenter: nil)
+        var coordinatorError: NSError?
+        var dbPool: Self?
+        var dbError: Error?
+
+        coordinator.coordinate(writingItemAt: url, options: .forMerging, error: &coordinatorError) { coordinatedURL in
+            do {
+                var configuration = Configuration()
+
+                configuration.prepareDatabase { db in
+                    try db.usePassphrase(passphrase())
+                    try db.execute(sql: "PRAGMA cipher_plaintext_header_size = 32")
+
+                    if !db.configuration.readonly {
+                        var flag: CInt = 1
+                        let code = withUnsafeMutablePointer(to: &flag) {
+                            sqlite3_file_control(db.sqliteConnection, nil, SQLITE_FCNTL_PERSIST_WAL, $0)
+                        }
+
+                        guard code == SQLITE_OK else {
+                            throw DatabaseError(resultCode: ResultCode(rawValue: code))
+                        }
+                    }
+                }
+
+                dbPool = try Self(path: coordinatedURL.path, configuration: configuration)
+
+                try migrator.migrate(dbPool!)
+            } catch {
+                dbError = error
+            }
+        }
+
+        if let error = dbError ?? coordinatorError {
+            throw error
+        }
+
+        return dbPool!
+    }
+}

DB/Sources/DB/Extensions/FileManager+Extensions.swift

@@ -3,12 +3,17 @@
 import Foundation
 
 extension FileManager {
-    func databaseDirectoryURL(name: String) throws -> URL {
+    enum DatabaseDirectoryError: Error {
-        let databaseDirectoryURL = try url(for: .applicationSupportDirectory,
+        case containerURLNotFound
-                                           in: .userDomainMask,
+        case unexpectedFileExistsWithDBDirectoryName
-                                           appropriateFor: nil,
+    }
-                                           create: true)
+
-            .appendingPathComponent("DB")
+    func databaseDirectoryURL(name: String, appGroup: String) throws -> URL {
+        guard let containerURL = containerURL(forSecurityApplicationGroupIdentifier: appGroup) else {
+            throw DatabaseDirectoryError.containerURLNotFound
+        }
+
+        let databaseDirectoryURL = containerURL.appendingPathComponent("DB")
         var isDirectory: ObjCBool = false
 
         if !fileExists(atPath: databaseDirectoryURL.path, isDirectory: &isDirectory) {
@@ -16,7 +21,7 @@ extension FileManager {
                                 withIntermediateDirectories: false,
                                 attributes: [.protectionKey: FileProtectionType.complete])
         } else if !isDirectory.boolValue {
-            throw NSError(domain: NSCocoaErrorDomain, code: NSFileWriteFileExistsError, userInfo: nil)
+            throw DatabaseDirectoryError.unexpectedFileExistsWithDBDirectoryName
         }
 
         return databaseDirectoryURL.appendingPathComponent(name)

DB/Sources/DB/Identity/IdentityDatabase+Migration.swift

@@ -3,7 +3,7 @@
 import GRDB
 
 extension IdentityDatabase {
-    var migrator: DatabaseMigrator {
+    static var migrator: DatabaseMigrator {
         var migrator = DatabaseMigrator()
 
         migrator.registerMigration("0.1.0") { db in

DB/Sources/DB/Identity/IdentityDatabase.swift

@@ -14,21 +14,17 @@ public enum IdentityDatabaseError: Error {
 public struct IdentityDatabase {
     private let databaseWriter: DatabaseWriter
 
-    public init(inMemory: Bool, keychain: Keychain.Type) throws {
+    public init(inMemory: Bool, appGroup: String, keychain: Keychain.Type) throws {
         if inMemory {
             databaseWriter = DatabaseQueue()
+            try Self.migrator.migrate(databaseWriter)
         } else {
-            let path = try FileManager.default.databaseDirectoryURL(name: Self.name).path
+            let url = try FileManager.default.databaseDirectoryURL(name: Self.name, appGroup: appGroup)
-            var configuration = Configuration()
 
-            configuration.prepareDatabase {
+            databaseWriter = try DatabasePool.withFileCoordinator(url: url, migrator: Self.migrator) {
-                try $0.usePassphrase(Secrets.databaseKey(identityId: nil, keychain: keychain))
+                try Secrets.databaseKey(identityId: nil, keychain: keychain)
             }
-
-            databaseWriter = try DatabasePool(path: path, configuration: configuration)
         }
-
-        try migrator.migrate(databaseWriter)
     }
 }
 

Secrets/Sources/Secrets/Secrets.swift

@@ -172,7 +172,7 @@ public extension Secrets {
 
 private extension Secrets {
     static let keychainServiceName = "com.metabolist.metatext"
-    static let databaseKeyLength = 32
+    static let databaseKeyLength = 48
 
     private static func set(_ data: SecretsStorable, forAccount account: String, keychain: Keychain.Type) throws {
         try keychain.setGenericPassword(

ServiceLayer/Sources/ServiceLayer/Entities/AppEnvironment.swift

@@ -40,12 +40,14 @@ public struct AppEnvironment {
 }
 
 public extension AppEnvironment {
+    static let appGroup = "group.metabolist.metatext"
+
     static func live(userNotificationCenter: UNUserNotificationCenter, reduceMotion: @escaping () -> Bool) -> Self {
         Self(
             session: URLSession.shared,
             webAuthSessionType: LiveWebAuthSession.self,
             keychain: LiveKeychain.self,
-            userDefaults: .standard,
+            userDefaults: UserDefaults(suiteName: appGroup)!,
             userNotificationClient: .live(userNotificationCenter),
             reduceMotion: reduceMotion,
             uuid: UUID.init,

ServiceLayer/Sources/ServiceLayer/Services/AllIdentitiesService.swift

@@ -18,6 +18,7 @@ public struct AllIdentitiesService {
         self.environment = environment
         self.database =  try environment.fixtureDatabase ?? IdentityDatabase(
             inMemory: environment.inMemoryContent,
+            appGroup: AppEnvironment.appGroup,
             keychain: environment.keychain)
         identitiesCreated = identitiesCreatedSubject.eraseToAnyPublisher()
     }
@@ -88,7 +89,7 @@ public extension AllIdentitiesService {
         database.deleteIdentity(id: id)
             .collect()
             .tryMap { _ -> AnyPublisher<Never, Error> in
-                try ContentDatabase.delete(id: id)
+                try ContentDatabase.delete(id: id, appGroup: AppEnvironment.appGroup)
 
                 let secrets = Secrets(identityId: id, keychain: environment.keychain)
 

ServiceLayer/Sources/ServiceLayer/Services/IdentityService.swift

@@ -34,6 +34,7 @@ public struct IdentityService {
             useHomeTimelineLastReadId: appPreferences.homeTimelineBehavior == .rememberPosition,
             useNotificationsLastReadId: appPreferences.notificationsTabBehavior == .rememberPosition,
             inMemory: environment.inMemoryContent,
+            appGroup: AppEnvironment.appGroup,
             keychain: environment.keychain)
     }
 }

Supporting Files/Metatext.entitlements

@@ -11,6 +11,10 @@
 	</array>
 	<key>com.apple.security.app-sandbox</key>
 	<true/>
+	<key>com.apple.security.application-groups</key>
+	<array>
+		<string>group.metabolist.metatext</string>
+	</array>
 	<key>com.apple.security.network.client</key>
 	<true/>
 	<key>keychain-access-groups</key>

ViewModels/Sources/PreviewViewModels/PreviewViewModels.swift

@@ -15,7 +15,7 @@ import ViewModels
 
 let db: IdentityDatabase = {
     let id = Identity.Id()
-    let db = try! IdentityDatabase(inMemory: true, keychain: MockKeychain.self)
+    let db = try! IdentityDatabase(inMemory: true, appGroup: "", keychain: MockKeychain.self)
     let secrets = Secrets(identityId: id, keychain: MockKeychain.self)
 
     try! secrets.setInstanceURL(.previewInstanceURL)