Fix 'database locked' error upon logout.

SQLite ROLLBACK TO command for savepoints does NOT actually
release the savepoint (transaction) which effectively keeps a lock on the database.

(cherry picked from commit 4d2ef9c)

Tinodios/UiUtils.swift

@@ -237,9 +237,8 @@ class UiUtils {
     public static func logoutAndRouteToLoginVC() {
         Cache.log.info("UiUtils - Invalidating cache and logging out.")
         SharedUtils.removeAuthToken()
-        UiUtils.routeToLoginVC() {
-            Cache.invalidate()
-        }
+        Cache.invalidate()
+        UiUtils.routeToLoginVC()
     }
 
     private static func routeToLoginVC(completion: (() -> (Void))? = nil) {

TinodiosDB/AccountDb.swift

@@ -57,6 +57,12 @@ public class AccountDb {
         try! self.db.run(self.table.createIndex(uid, unique: true, ifNotExists: true))
         try! self.db.run(self.table.createIndex(active, ifNotExists: true))
     }
+
+    // Deletes all records from `accounts` table.
+    public func truncateTable() {
+        try! self.db.run(self.table.delete())
+    }
+
     @discardableResult
     func deactivateAll() throws -> Int {
         return try self.db.run(self.table.update(self.active <- 0))
@@ -68,9 +74,10 @@ public class AccountDb {
         return nil
     }
     func addOrActivateAccount(for uid: String, withCredMethods meth: [String]?) -> StoredAccount? {
+        let savepointName = "AccountDb.addOrActivateAccount"
         var result: StoredAccount?
         do {
-            try db.savepoint("AccountDb.addOrActivateAccount") {
+            try db.savepoint(savepointName) {
                 try self.deactivateAll()
                 result = self.getByUid(uid: uid)
                 let serializedCredMeth = meth?.joined(separator: ",")
@@ -93,9 +100,13 @@ public class AccountDb {
                 }
             }
         } catch SQLite.Result.error(message: let err, code: let code, statement: _) {
+            // Explicitly releasing savepoint since ROLLBACK TO (SQLite.swift behavior) won't release the savepoint transaction.
+            self.db.releaseSavepoint(withName: savepointName)
             BaseDb.log.error("Failed to add account for uid %@: SQLite code = %d, error = %@", uid, code, err)
             result = nil
         } catch {
+            // Explicitly releasing savepoint since ROLLBACK TO (SQLite.swift behavior) won't release the savepoint transaction.
+            self.db.releaseSavepoint(withName: savepointName)
             BaseDb.log.error("Failed to add account '%@'", error.localizedDescription)
             result = nil
         }

TinodiosDB/BaseDb.swift

@@ -123,6 +123,17 @@ public class BaseDb {
         self.account = self.accountDb!.getActiveAccount()
     }
 
+    private func clearDb() {
+        BaseDb.log.info("Clearing local store (SQLite db).")
+        try! self.db!.transaction {
+            self.messageDb?.truncateTable()
+            self.subscriberDb?.truncateTable()
+            self.topicDb?.truncateTable()
+            self.userDb?.truncateTable()
+            self.accountDb?.truncateTable()
+        }
+    }
+
     private func dropDb() {
         BaseDb.log.info("Dropping local store (SQLite db).")
         self.messageDb?.destroyTable()
@@ -174,7 +185,7 @@ public class BaseDb {
         // _ = try? self.accountDb?.deactivateAll()
         // self.setUid(uid: nil, credMethods: nil)
         BaseDb.accessQueue.sync {
-            self.dropDb()
+            self.clearDb()
             BaseDb.default = nil
         }
     }
@@ -191,8 +202,9 @@ public class BaseDb {
             BaseDb.log.error("Could not find account for uid [%@]", uid)
             return false
         }
+        let savepointName = "BaseDb.deleteUid"
         do {
-            try self.db?.savepoint("BaseDb.deleteUid") {
+            try self.db?.savepoint(savepointName) {
                 if !(self.topicDb?.deleteAll(forAccount: acc2.id) ?? true) {
                     BaseDb.log.error("Failed to clear topics/messages/subscribers for account id [%lld]", acc2.id)
                 }
@@ -204,6 +216,8 @@ public class BaseDb {
                 }
             }
         } catch {
+            // Explicitly releasing savepoint since ROLLBACK TO (SQLite.swift behavior) won't release the savepoint transaction.
+            self.db?.releaseSavepoint(withName: savepointName)
             BaseDb.log.error("BaseDb - deleteUid operation failed: uid = %@, error = %@", uid, error.localizedDescription)
             return false
         }
@@ -238,4 +252,9 @@ extension SQLite.Connection {
         get { return Int32((try? scalar("PRAGMA user_version") as? Int64) ?? -1) }
         set { try! run("PRAGMA user_version = \(newValue)") }
     }
+
+    /// Releases a savepoint explicitly.
+    public func releaseSavepoint(withName savepointName: String) {
+        try! self.execute("RELEASE '\(savepointName)'")
+    }
 }

TinodiosDB/MessageDb.swift

@@ -69,7 +69,6 @@ public class MessageDb {
         self.content = Expression<String?>("content")
     }
     func destroyTable() {
-        if self.db.locked
         try! self.db.run(self.table.dropIndex(topicId, effectiveSeq.desc, ifExists: true))
         try! self.db.run(self.table.dropIndex(topicId, seq.desc, ifExists: true))
         try! self.db.run(self.table.drop(ifExists: true))
@@ -100,6 +99,12 @@ public class MessageDb {
         try! self.db.run([partIdx, "WHERE", (self.effectiveSeq != nil).asSQL()].joined(separator: " "))
     }
 
+    // Deletes all records from `messages` table.
+    func truncateTable() {
+        // Note: SQLite optimizes 'DELETE FROM table' to behave like `TRUNCATE TABLE`.
+        try! self.db.run(self.table.delete())
+    }
+
     @discardableResult
     private func insertRaw(topic: TopicProto, msg: StoredMessage, withEffectiveSeq effectiveSeqId: Int?,
                            withEffectiveTs effectiveTs: Date?) throws -> Int64 {
@@ -186,8 +191,9 @@ public class MessageDb {
         if (msg.topicId ?? -1) <= 0 {
             msg.topicId = topicId
         }
+        let savepointName = "MessageDb.insert"
         do {
-            try db.savepoint("MessageDb.insert") {
+            try db.savepoint(savepointName) {
                 var effSeq: Int?
                 var effTs: Date?
                 if let replaceSeq = msg.replacesSeq {
@@ -221,9 +227,13 @@ public class MessageDb {
             }
             return msg.msgId
         } catch SQLite.Result.error(message: let errMsg, code: let code, statement: _) {
+            // Explicitly releasing savepoint since ROLLBACK TO (SQLite.swift behavior) won't release the savepoint transaction.
+            self.db.releaseSavepoint(withName: savepointName)
             BaseDb.log.error("MessageDb[topic: %@, seq: %d] - insert SQLite error: code = %d, error = %@", topic.name, msg.seqId, code, errMsg)
             return -1
         } catch {
+            // Explicitly releasing savepoint since ROLLBACK TO (SQLite.swift behavior) won't release the savepoint transaction.
+            self.db.releaseSavepoint(withName: savepointName)
             BaseDb.log.error("MessageDb - insert operation failed: %@", error.localizedDescription.debugDescription)
             return -1
         }
@@ -309,8 +319,9 @@ public class MessageDb {
     @discardableResult
     func deleteOrMarkDeleted(topicId: Int64, delId: Int?, inRanges ranges: [MsgRange], hard: Bool) -> Bool {
         var success = false
+        let savepointName = "MessageDb.deleteOrMarkDeleted-ranges"
         do {
-            try db.savepoint("MessageDb.deleteOrMarkDeleted-ranges") {
+            try db.savepoint(savepointName) {
                 for r in ranges {
                     if !deleteOrMarkDeleted(topicId: topicId, delId: delId, from: r.lower, to: r.upper, hard: hard) {
                         throw MessageDbError.dbError("Failed to process: delId \(delId ?? -1) range: \(r)")
@@ -319,8 +330,12 @@ public class MessageDb {
             }
             success = true
         } catch SQLite.Result.error(message: let errMsg, code: let code, statement: _) {
+            // Explicitly releasing savepoint since ROLLBACK TO (SQLite.swift behavior) won't release the savepoint transaction.
+            self.db.releaseSavepoint(withName: savepointName)
             BaseDb.log.error("MessageDb[topicId = %lld] - deleteOrMarkDeleted SQLite error: code = %d, error = %@", topicId, code, errMsg)
         } catch {
+            // Explicitly releasing savepoint since ROLLBACK TO (SQLite.swift behavior) won't release the savepoint transaction.
+            self.db.releaseSavepoint(withName: savepointName)
             BaseDb.log.error("MessageDb - deleteOrMarkDeleted2 with ranges failed: topicId = %lld, error = %@", topicId, error.localizedDescription)
         }
         return success
@@ -333,10 +348,11 @@ public class MessageDb {
         if endId == 0 {
             endId = startId + 1
         }
+        let savepointName = "MessageDb.deleteOrMarkDeleted-plain"
         // 1. Delete all messages in the range.
         do {
             var updateResult = false
-            try db.savepoint("MessageDb.deleteOrMarkDeleted-plain") {
+            try db.savepoint(savepointName) {
                 // Message selector: all messages in a given topic with seq between fromId and toId [inclusive, exclusive).
                 let messageSelector = self.table.filter(
                     self.topicId == topicId && startId <= self.seq && self.seq < endId && self.status <= BaseDb.Status.synced.rawValue)
@@ -395,9 +411,13 @@ public class MessageDb {
             }
             return updateResult
         } catch SQLite.Result.error(message: let errMsg, code: let code, statement: _) {
+            // Explicitly releasing savepoint since ROLLBACK TO (SQLite.swift behavior) won't release the savepoint transaction.
+            self.db.releaseSavepoint(withName: savepointName)
             BaseDb.log.error("MessageDb[topicId = %lld] - markDeleted SQLite error: code = %d, error = %@", topicId, code, errMsg)
             return false
         } catch {
+            // Explicitly releasing savepoint since ROLLBACK TO (SQLite.swift behavior) won't release the savepoint transaction.
+            self.db.releaseSavepoint(withName: savepointName)
             BaseDb.log.error("MessageDb - markDeleted operation failed: topicId = %lld, error = %@", topicId, error.localizedDescription)
             return false
         }

TinodiosDB/SqlStore.swift

@@ -84,19 +84,20 @@ public class SqlStore: Storage {
 
     public func topicDelete(topic: TopicProto, hard: Bool) -> Bool {
         guard let st = topic.payload as? StoredTopic, let topicId = st.id else { return false }
+        let savepointName = "SqlStore.topicDelete"
         do {
             if hard {
-                try dbh?.db?.savepoint("SqlStore.topicDelete") {
+                try dbh?.db?.savepoint(savepointName) {
                     self.dbh?.messageDb?.deleteAll(forTopic: topicId)
                     self.dbh?.subscriberDb?.deleteForTopic(topicId: topicId)
                     self.dbh?.topicDb?.delete(recordId: topicId)
-
                 }
             } else {
                 self.dbh?.topicDb?.markDeleted(recordId: topicId)
             }
             return true
         } catch {
+            dbh?.db?.releaseSavepoint(withName: savepointName)
             BaseDb.log.error("SqlStore - topicDelete operation failed: topicId = %lld, error = %@", topicId, error.localizedDescription)
             return false
         }
@@ -204,15 +205,17 @@ public class SqlStore: Storage {
         sm.topicId = topicId
         sm.userId = userId
         sm.dbStatus = .synced
+        let savepointName = "SqlStore.msgReceived"
         do {
-            try dbh?.db?.savepoint("SqlStore.msgReceived") {
+            try dbh?.db?.savepoint(savepointName) {
                 sm.msgId = self.dbh?.messageDb?.insert(topic: topic, msg: sm) ?? -1
                 if sm.msgId <= 0 || !(self.dbh?.topicDb?.msgReceived(topic: topic, ts: sm.ts ?? Date(), seq: sm.seqId) ?? false) {
                     throw SqlStoreError.dbError("Could not handle received message: msgId = \(sm.msgId), topicId = \(topicId), userId = \(userId)")
                 }
             }
             return sm
         } catch {
+            dbh?.db?.releaseSavepoint(withName: savepointName)
             BaseDb.log.error("SqlStore - msgReceived operation failed: %@", error.localizedDescription)
             return nil
         }
@@ -286,8 +289,9 @@ public class SqlStore: Storage {
     }
 
     public func msgDelivered(topic: TopicProto, dbMessageId: Int64, timestamp: Date, seq: Int) -> Bool {
+        let savepointName = "SqlStore.msgDelivered"
         do {
-            try dbh?.db?.savepoint("SqlStore.msgDelivered") {
+            try dbh?.db?.savepoint(savepointName) {
                 let messageDbSuccessful = self.dbh?.messageDb?.delivered(msgId: dbMessageId, ts: timestamp, seq: seq) ?? false
                 let topicDbSuccessful = self.dbh?.topicDb?.msgReceived(topic: topic, ts: timestamp, seq: seq) ?? false
                 if !(messageDbSuccessful && topicDbSuccessful) {
@@ -296,6 +300,7 @@ public class SqlStore: Storage {
             }
             return true
         } catch {
+            dbh?.db?.releaseSavepoint(withName: savepointName)
             BaseDb.log.error("SqlStore - msgDelivered operation failed %@", error.localizedDescription)
             return false
         }
@@ -316,12 +321,14 @@ public class SqlStore: Storage {
         guard let st = topic.payload as? StoredTopic, let topicId = st.id else { return false }
         let idHi = idHi <= 0 ? (st.maxLocalSeq ?? 0) + 1 : idHi
         var success = false
+        let savepointName = "SqlStore.msgDelete-bounds"
         do {
-            try dbh?.db?.savepoint("SqlStore.msgDelete-bounds") {
+            try dbh?.db?.savepoint(savepointName) {
                 success = (dbh?.topicDb?.msgDeleted(topic: topic, delId: delId, from: idLo, to: idHi) ?? false) &&
                     (dbh?.messageDb?.delete(topicId: topicId, deleteId: delId, from: idLo, to: idHi) ?? false)
             }
         } catch {
+            dbh?.db?.releaseSavepoint(withName: savepointName)
             BaseDb.log.error("SqlStore - msgDelete operation failed %@", error.localizedDescription)
         }
         return success
@@ -333,12 +340,15 @@ public class SqlStore: Storage {
         let collapsedRanges = MsgRange.collapse(ranges)
         let enclosing = MsgRange.enclosing(for: collapsedRanges)
         var success = false
+        let savepointName = "SqlStore.msgDelete-ranges"
         do {
-            try dbh?.db?.savepoint("SqlStore.msgDelete-ranges") {
+            try dbh?.db?.savepoint(savepointName) {
                 success = (dbh?.topicDb?.msgDeleted(topic: topic, delId: delId, from: enclosing!.lower, to: enclosing!.upper) ?? false) &&
                     (dbh?.messageDb?.deleteOrMarkDeleted(topicId: topicId, delId: delId, inRanges: collapsedRanges, hard: false) ?? false)
             }
         } catch {
+            // Explicitly releasing savepoint since ROLLBACK TO (SQLite.swift behavior) won't release the savepoint transaction.
+            dbh?.db?.releaseSavepoint(withName: savepointName)
             BaseDb.log.error("SqlStore - msgDelete operation failed %@", error.localizedDescription)
         }
         return success

TinodiosDB/SubscriberDb.swift

@@ -88,10 +88,17 @@ public class SubscriberDb {
         })
         try! self.db.run(self.table.createIndex(topicId, ifNotExists: true))
     }
+
+    // Deletes all records from `subscribers` table.
+    func truncateTable() {
+        try! self.db.run(self.table.delete())
+    }
+
     func insert(for topicId: Int64, with status: BaseDb.Status, using sub: SubscriptionProto) -> Int64 {
         var rowId: Int64 = -1
+        let savepointName = "SubscriberDb.insert"
         do {
-            try self.db.savepoint("SubscriberDb.insert") {
+            try self.db.savepoint(savepointName) {
                 let ss = StoredSubscription()
                 let userDb = baseDb.userDb!
                 ss.userId = userDb.getId(for: sub.user)
@@ -125,6 +132,8 @@ public class SubscriberDb {
                 sub.payload = ss
             }
         } catch {
+            // Explicitly releasing savepoint since ROLLBACK TO (SQLite.swift behavior) won't release the savepoint transaction.
+            self.db.releaseSavepoint(withName: savepointName)
             BaseDb.log.error("SubscriberDb - insert operation failed: topicId = %lld, error = %@", topicId, error.localizedDescription)
             return -1
         }
@@ -136,8 +145,9 @@ public class SubscriberDb {
         }
         let record = self.table.filter(self.id == recordId)
         var updated = 0
+        let savepointName = "SubscriberDb.update"
         do {
-            try self.db.savepoint("SubscriberDb.update") {
+            try self.db.savepoint(savepointName) {
                 var status = ss.status!
                 _ = baseDb.userDb!.update(sub: sub)
                 var setters = [Setter]()
@@ -159,6 +169,8 @@ public class SubscriberDb {
                 ss.status = status
             }
         } catch {
+            // Explicitly releasing savepoint since ROLLBACK TO (SQLite.swift behavior) won't release the savepoint transaction.
+            self.db.releaseSavepoint(withName: savepointName)
             BaseDb.log.error("SubscriberDb - update operation failed: subId = %lld, error = %@", recordId, error.localizedDescription)
             return false
         }

TinodiosDB/TopicDb.swift

@@ -128,6 +128,11 @@ public class TopicDb {
         try! db.run(self.table.createIndex(accountId, topic, unique: true, ifNotExists: true))
     }
 
+    // Deletes all records from `topics` table.
+    public func truncateTable() {
+        try! self.db.run(self.table.delete())
+    }
+
     public static func isUnsentSeq(seq: Int) -> Bool {
         return seq >= TopicDb.kUnsentIdStart
     }

TinodiosDB/UserDb.swift

@@ -59,6 +59,11 @@ public class UserDb {
         try! self.db.run(self.table.createIndex(accountId, uid, ifNotExists: true))
     }
 
+    // Deletes all records from `users` table.
+    public func truncateTable() {
+        try! self.db.run(self.table.delete())
+    }
+
     public func insert(user: UserProto?) -> Int64 {
         guard let user = user else { return 0 }
         let id = self.insert(uid: user.uid, updated: user.updated, serializedPub: user.serializePub())