agent: support closing and re-opening store (#855)

* agent: support closing and re-opening store

* add closed flag, tests

src/Simplex/Messaging/Agent/Store/SQLite.hs

@@ -31,6 +31,7 @@ module Simplex.Messaging.Agent.Store.SQLite
     createSQLiteStore,
     connectSQLiteStore,
     closeSQLiteStore,
+    openSQLiteStore,
     sqlString,
     execSQL,
     upMigration, -- used in tests
@@ -269,13 +270,13 @@ import Simplex.Messaging.Parsers (blobFieldParser, dropPrefix, fromTextField_, s
 import Simplex.Messaging.Protocol
 import qualified Simplex.Messaging.Protocol as SMP
 import Simplex.Messaging.Transport.Client (TransportHost)
-import Simplex.Messaging.Util (bshow, eitherToMaybe, groupOn, ($>>=), (<$$>))
+import Simplex.Messaging.Util (bshow, eitherToMaybe, groupOn, ifM, ($>>=), (<$$>))
 import Simplex.Messaging.Version
 import System.Directory (copyFile, createDirectoryIfMissing, doesFileExist)
 import System.Exit (exitFailure)
 import System.FilePath (takeDirectory)
 import System.IO (hFlush, stdout)
-import UnliftIO.Exception (onException)
+import UnliftIO.Exception (onException, bracketOnError)
 import qualified UnliftIO.Exception as E
 import UnliftIO.STM
 
@@ -379,10 +380,12 @@ confirmOrExit s = do
 connectSQLiteStore :: FilePath -> String -> IO SQLiteStore
 connectSQLiteStore dbFilePath dbKey = do
   dbNew <- not <$> doesFileExist dbFilePath
-  dbConn <- dbBusyLoop $ connectDB dbFilePath dbKey
-  dbConnVar <- newTMVarIO dbConn
-  dbEncrypted <- newTVarIO . not $ null dbKey
-  pure SQLiteStore {dbFilePath, dbEncrypted, dbConnection = dbConnVar, dbNew}
+  dbConn <- dbBusyLoop (connectDB dbFilePath dbKey)
+  atomically $ do
+    dbConnection <- newTMVar dbConn
+    dbEncrypted <- newTVar . not $ null dbKey
+    dbClosed <- newTVar False
+    pure SQLiteStore {dbFilePath, dbEncrypted, dbConnection, dbNew, dbClosed}
 
 connectDB :: FilePath -> String -> IO DB.Connection
 connectDB path key = do
@@ -404,7 +407,25 @@ connectDB path key = do
         |]
 
 closeSQLiteStore :: SQLiteStore -> IO ()
-closeSQLiteStore st = atomically (takeTMVar $ dbConnection st) >>= DB.close
+closeSQLiteStore st@SQLiteStore {dbClosed} =
+  ifM (readTVarIO dbClosed) (putStrLn "closeSQLiteStore: already closed") $
+    withConnection st $ \conn -> do
+      DB.close conn
+      atomically $ writeTVar dbClosed True
+
+openSQLiteStore :: SQLiteStore -> String -> IO ()
+openSQLiteStore SQLiteStore {dbConnection, dbFilePath, dbClosed} key =
+  ifM (readTVarIO dbClosed) open (putStrLn "closeSQLiteStore: already opened")
+  where
+    open =
+      bracketOnError
+        (atomically $ takeTMVar dbConnection)
+        (atomically . tryPutTMVar dbConnection)
+        $ \DB.Connection {slow} -> do
+          DB.Connection {conn} <- connectDB dbFilePath key
+          atomically $ do
+            putTMVar dbConnection DB.Connection {conn, slow}
+            writeTVar dbClosed False
 
 sqlString :: String -> Text
 sqlString s = quote <> T.replace quote "''" (T.pack s) <> quote

src/Simplex/Messaging/Agent/Store/SQLite/Common.hs

@@ -27,6 +27,7 @@ data SQLiteStore = SQLiteStore
   { dbFilePath :: FilePath,
     dbEncrypted :: TVar Bool,
     dbConnection :: TMVar DB.Connection,
+    dbClosed :: TVar Bool,
     dbNew :: Bool
   }
 

src/Simplex/Messaging/Util.hs

@@ -3,13 +3,11 @@
 
 module Simplex.Messaging.Util where
 
-import Control.Concurrent (threadDelay)
 import qualified Control.Exception as E
 import Control.Monad
 import Control.Monad.Except
 import Control.Monad.IO.Unlift
 import Data.Bifunctor (first)
-import qualified Data.ByteString as BW
 import Data.ByteString.Char8 (ByteString)
 import qualified Data.ByteString.Char8 as B
 import Data.Int (Int64)
@@ -21,7 +19,6 @@ import qualified Data.Text as T
 import Data.Text.Encoding (decodeUtf8With)
 import Data.Time (NominalDiffTime)
 import GHC.Conc
-import Numeric (showHex)
 import UnliftIO.Async
 import qualified UnliftIO.Exception as UE