Network/MPD/StringConn.hs

   1 {-
   2     libmpd for Haskell, an MPD client library.
   3     Copyright (C) 2005-2007  Ben Sinclair <bsinclai@turing.une.edu.au>
   4
   5     This library is free software; you can redistribute it and/or
   6     modify it under the terms of the GNU Lesser General Public
   7     License as published by the Free Software Foundation; either
   8     version 2.1 of the License, or (at your option) any later version.
   9
  10     This library is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13     Lesser General Public License for more details.
  14
  15     You should have received a copy of the GNU Lesser General Public
  16     License along with this library; if not, write to the Free Software
  17     Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  18 -}
  19
  20 -- | Module    : Network.MPD.StringConn
  21 -- Copyright   : (c) Ben Sinclair 2005-2007
  22 -- License     : LGPL
  23 -- Maintainer  : bsinclai@turing.une.edu.au
  24 -- Stability   : alpha
  25 -- Portability : Haskell 98
  26 --
  27 -- Connection over a network socket.
  28
  29 module Network.MPD.StringConn (Expect, Result(..), testMPD) where
  30
  31 import Control.Monad (liftM)
  32 import Prelude hiding (exp)
  33 import Network.MPD.Core
  34 import Data.IORef
  35
  36 -- | An expected request.
  37 type Expect = String
  38
  39 data Result a = Ok | Failure (Response a) [(Expect,String)]
  40                 deriving Show
  41
  42 -- | Run an action against a set of expected requests and responses,
  43 -- and an expected result. The result is Nothing if everything matched
  44 -- what was expected. If anything differed the result of the
  45 -- computation is returned along with pairs of expected and received
  46 -- requests.
  47 testMPD :: (Eq a)
  48         => [(Expect, Response String)] -- ^ The expected requests and their
  49                                        -- ^ corresponding responses.
  50         -> Response a                  -- ^ The expected result.
  51         -> IO (Maybe String)           -- ^ An action that supplies passwords.
  52         -> MPD a                       -- ^ The MPD action to run.
  53         -> IO (Result a)
  54 testMPD pairs expected getpw m = do
  55     expectsRef    <- newIORef pairs
  56     mismatchesRef <- newIORef ([] :: [(Expect, String)])
  57     let open'  = return ()
  58         close' = return ()
  59         send'  = send expectsRef mismatchesRef
  60     result <- runMPD m $ Conn open' close' send' getpw
  61     mismatches <- liftM reverse $ readIORef mismatchesRef
  62     return $ if null mismatches && result == expected
  63              then Ok
  64              else Failure result mismatches
  65
  66 send :: IORef [(Expect, Response String)] -- Expected requests and their
  67                                           -- responses.
  68      -> IORef [(Expect, String)]          -- An initially empty list of
  69                                           -- mismatches between expected and
  70                                           -- actual requests.
  71      -> String
  72      -> IO (Response String)
  73 send expsR mmsR str = do
  74     xs <- readIORef expsR
  75     case xs of
  76         ((exp,resp):_) | exp == str -> modifyIORef expsR (drop 1) >> return resp
  77                        | otherwise  -> addMismatch exp
  78         [] -> addMismatch ""
  79     where
  80         addMismatch exp = modifyIORef mmsR ((exp,str):) >> return (Left NoMPD)