    -- Copyright (C) 2002-2004,2007-2008 David Roundy
    -- Copyright (C) 2005 Juliusz Chroboczek
    --
    -- This program is free software; you can redistribute it and/or modify
    -- it under the terms of the GNU General Public License as published by
    -- the Free Software Foundation; either version 2, or (at your option)
    -- any later version.
    --
    -- This program is distributed in the hope that it will be useful,
    -- but WITHOUT ANY WARRANTY; without even the implied warranty of
    -- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    -- GNU General Public License for more details.
    --
    -- You should have received a copy of the GNU General Public License
    -- along with this program; see the file COPYING.  If not, write to
    -- the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
    -- Boston, MA 02110-1301, USA.

    {-# OPTIONS_GHC -cpp -fglasgow-exts #-}
    {-# LANGUAGE CPP #-}

    #include "gadts.h"

    module Darcs.Repository.LowLevel ( read_pending, read_pendingfile, pendingName, readPrims ) where

    import Darcs.Repository.InternalTypes ( RepoType(..), Repository(..) )
    import Darcs.Patch ( readPatch, Prim, Patch, RepoPatch, effect )
    import Darcs.Global ( darcsdir )
    import Darcs.Witnesses.Sealed ( Sealed(Sealed) )
    import Darcs.Witnesses.Ordered ( FL(..) )
    import Darcs.Utils ( catchall, withCurrentDirectory )
    import ByteStringUtils ( gzReadFilePS )
    import qualified Data.ByteString as BS ( ByteString, empty )

    pendingName :: RepoType p -> String
    pendingName (DarcsRepository _ _) = darcsdir++"/patches/pending"

    read_pending :: RepoPatch p => Repository p C(r u t) -> IO (Sealed (FL Prim C(r)))
    read_pending (Repo r _ _ tp) =
        withCurrentDirectory r (read_pendingfile (pendingName tp))

    read_pendingfile :: String -> IO (Sealed (FL Prim C(x)))
    read_pendingfile name = do
      pend <- gzReadFilePS name `catchall` return BS.empty
      return $ readPrims pend

    readPrims :: BS.ByteString -> Sealed (FL Prim C(x))
    readPrims s = case readPatch s :: Maybe (Sealed (Patch C(x )), BS.ByteString) of
                  Nothing -> Sealed NilFL
                  Just (Sealed p,_) -> Sealed (effect p)