remote: use DList Logger

instead of slow-to-append-to list. Thanks for the suggestion!

Closes #63.

Co-Authored-By: Travis Whitaker <pi.boy.travis@gmail.com>

docs/01-Contributors.org

@@ -28,4 +28,5 @@ in order of appearance:
 + Luigy Leon @luigy
 + squalus @squalus
 + Vaibhav Sagar @vaibhavsagar
-* Ryan Trinkle @ryantrinkle
++ Ryan Trinkle @ryantrinkle
++ Travis Whitaker @TravisWhitaker

hnix-store-remote/hnix-store-remote.cabal

@@ -117,6 +117,7 @@ library
     , data-default-class
     , dependent-sum > 0.7
     , dependent-sum-template > 0.1.1 && < 0.3
+    , dlist >= 1.0
     , generic-arbitrary < 1.1
     , hashable
     , text

hnix-store-remote/src/System/Nix/Store/Remote.hs

@@ -121,7 +121,7 @@ runStoreOptsTCP host port sd code = do
           (Network.Socket.addrAddress sockAddr)
           sd
           code
-      _ -> pure (Left RemoteStoreError_GetAddrInfoFailed, [])
+      _ -> pure (Left RemoteStoreError_GetAddrInfoFailed, mempty)
 
 runStoreOpts'
   :: Family

hnix-store-remote/src/System/Nix/Store/Remote/Client.hs

@@ -17,6 +17,7 @@ module System.Nix.Store.Remote.Client
 import Control.Monad (unless, when)
 import Control.Monad.Except (throwError)
 import Control.Monad.IO.Class (MonadIO, liftIO)
+import Data.DList (DList)
 import Data.Serialize.Put (Put, runPut)
 import Data.Some (Some(Some))
 
@@ -157,7 +158,7 @@ addToStore name source method hashAlgo repair = do
 isValidPath :: MonadRemoteStore m => StorePath -> m Bool
 isValidPath = doReq . IsValidPath
 
-type Run m a = m (Either RemoteStoreError a, [Logger])
+type Run m a = m (Either RemoteStoreError a, DList Logger)
 
 runStoreSocket
   :: ( Monad m

hnix-store-remote/src/System/Nix/Store/Remote/MonadStore.hs

@@ -24,6 +24,7 @@ import Control.Monad.Trans.State.Strict (StateT, runStateT, mapStateT)
 import Control.Monad.Trans.Except (ExceptT, runExceptT, mapExceptT)
 import Control.Monad.Trans.Reader (ReaderT, runReaderT, withReaderT)
 import Data.ByteString (ByteString)
+import Data.DList (DList)
 import Data.Word (Word64)
 import Network.Socket (Socket)
 import System.Nix.Nar (NarSource)
@@ -33,8 +34,10 @@ import System.Nix.Store.Remote.Types.Logger (Logger)
 import System.Nix.Store.Remote.Types.ProtoVersion (HasProtoVersion(..), ProtoVersion)
 import System.Nix.Store.Remote.Types.StoreConfig (HasStoreSocket(..), StoreConfig)
 
+import qualified Data.DList
+
 data RemoteStoreState = RemoteStoreState {
-    remoteStoreState_logs :: [Logger]
+    remoteStoreState_logs :: DList Logger
   , remoteStoreState_gotError :: Bool
   , remoteStoreState_mDataSource :: Maybe (Word64 -> IO (Maybe ByteString))
   -- ^ Source for @Logger_Read@, this will be called repeatedly
@@ -121,7 +124,7 @@ runRemoteStoreT
      )
   => r
   -> RemoteStoreT r m a
-  -> m (Either RemoteStoreError a, [Logger])
+  -> m (Either RemoteStoreError a, DList Logger)
 runRemoteStoreT r =
     fmap (\(res, RemoteStoreState{..}) -> (res, remoteStoreState_logs))
   . (`runReaderT` r)
@@ -304,7 +307,7 @@ instance ( MonadIO m
   appendLog x =
     RemoteStoreT
     $ modify
-    $ \s -> s { remoteStoreState_logs = remoteStoreState_logs s ++ [x] }
+    $ \s -> s { remoteStoreState_logs = remoteStoreState_logs s `Data.DList.snoc` x }
 
   setError = RemoteStoreT $ modify $ \s -> s { remoteStoreState_gotError = True }
   clearError = RemoteStoreT $ modify $ \s -> s { remoteStoreState_gotError = False }

hnix-store-remote/tests-io/NixDaemon.hs

@@ -29,6 +29,7 @@ import System.Nix.Build
 import System.Nix.StorePath
 import System.Nix.StorePath.Metadata
 import System.Nix.Store.Remote
+import System.Nix.Store.Remote.Client (Run)
 import System.Nix.Store.Remote.MonadStore (mapStoreConfig)
 
 import Crypto.Hash (SHA256)
@@ -89,7 +90,7 @@ error: changing ownership of path '/run/user/1000/test-nix-store-06b0d249e561612
 
 startDaemon
   :: FilePath
-  -> IO (P.ProcessHandle, MonadStore a -> IO (Either RemoteStoreError a, [Logger]))
+  -> IO (P.ProcessHandle, MonadStore a -> Run IO a)
 startDaemon fp = do
   writeConf (fp </> "etc" </> "nix.conf")
   p <- createProcessEnv fp "nix-daemon" []
@@ -110,7 +111,7 @@ enterNamespaces = do
   writeGroupMappings Nothing [GroupMapping 0 gid 1] True
 
 withNixDaemon
-  :: ((MonadStore a -> IO (Either RemoteStoreError a, [Logger])) -> IO a) -> IO a
+  :: ((MonadStore a -> Run IO a) -> IO a) -> IO a
 withNixDaemon action =
   withSystemTempDirectory "test-nix-store" $ \path -> do