320 lines
10 KiB
Haskell
320 lines
10 KiB
Haskell
--------------------------------------------------------------------------------
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-- | Functions for handling dependencies
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module XMonad.Internal.Dependency
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( MaybeAction
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, MaybeX
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, FeatureX
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, FeatureIO
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, Feature(..)
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, Warning(..)
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, Dependency(..)
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, UnitType(..)
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, Bus(..)
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, Endpoint(..)
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, DBusMember(..)
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, ioFeature
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, evalFeature
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, systemUnit
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, userUnit
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, pathR
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, pathW
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, pathRW
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, featureDefault
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, featureExeArgs
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, featureExe
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, warnMissing
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, whenSatisfied
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, ifSatisfied
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, executeFeature
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, executeFeature_
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, applyFeature
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, applyFeature_
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, callMethod
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) where
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import Control.Monad.IO.Class
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import Data.Bifunctor (bimap)
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import Data.List (find)
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import Data.Maybe (catMaybes, fromMaybe, listToMaybe)
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import DBus
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import DBus.Client
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import qualified DBus.Introspection as I
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import System.Directory (findExecutable, readable, writable)
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import System.Environment
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import System.Exit
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import XMonad.Core (X, io)
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import XMonad.Internal.IO
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import XMonad.Internal.Process
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import XMonad.Internal.Shell
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--------------------------------------------------------------------------------
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-- | Features
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--
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-- A 'feature' is an 'action' (usually an IO ()) that requires one or more
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-- 'dependencies'. Features also have a useful name and an error logging
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-- protocol.
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--
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-- NOTE: there is no way to make a feature depend on another feature. This is
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-- very complicated to implement and would only be applicable to a few instances
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-- (notable the dbus interfaces). In order to implement a dependency tree, use
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-- dependencies that target the output/state of another feature; this is more
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-- robust anyways, at the cost of being a bit slower.
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data Feature a = Feature
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{ ftrMaybeAction :: a
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, ftrName :: String
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, ftrWarning :: Warning
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, ftrChildren :: [Dependency]
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}
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| ConstFeature a
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| BlankFeature
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-- TODO this is silly as is, and could be made more useful by representing
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-- loglevels
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data Warning = Silent | Default
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type FeatureX = Feature (X ())
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type FeatureIO = Feature (IO ())
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ioFeature :: (MonadIO m) => Feature (IO a) -> Feature (m a)
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ioFeature f@Feature { ftrMaybeAction = a } = f { ftrMaybeAction = liftIO a }
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ioFeature (ConstFeature f) = ConstFeature $ liftIO f
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ioFeature BlankFeature = BlankFeature
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featureDefault :: String -> [Dependency] -> a -> Feature a
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featureDefault n ds x = Feature
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{ ftrMaybeAction = x
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, ftrName = n
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, ftrWarning = Default
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, ftrChildren = ds
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}
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featureExe :: MonadIO m => String -> String -> Feature (m ())
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featureExe n cmd = featureExeArgs n cmd []
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featureExeArgs :: MonadIO m => String -> String -> [String] -> Feature (m ())
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featureExeArgs n cmd args =
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featureDefault n [Executable cmd] $ spawnCmd cmd args
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--------------------------------------------------------------------------------
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-- | Feature evaluation
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--
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-- Evaluate a feature by testing if its dependencies are satisfied, and return
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-- either the action of the feature or 0 or more error messages that signify
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-- what dependencies are missing and why.
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type MaybeAction a = Either [String] a
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type MaybeX = MaybeAction (X ())
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evalFeature :: Feature a -> IO (MaybeAction a)
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evalFeature (ConstFeature x) = return $ Right x
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evalFeature BlankFeature = return $ Left []
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evalFeature Feature
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{ ftrMaybeAction = a
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, ftrName = n
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, ftrWarning = w
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, ftrChildren = c
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} = do
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procName <- getProgName
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es <- catMaybes <$> mapM evalDependency c
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return $ case es of
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[] -> Right a
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es' -> Left $ fmtWarnings procName es'
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where
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fmtWarnings procName es = case w of
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Silent -> []
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Default -> fmap (fmtMsg procName "WARNING" . ((n ++ " disabled; ") ++)) es
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applyFeature :: MonadIO m => (m a -> m a) -> a -> Feature (IO a) -> m a
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applyFeature iof def ftr = do
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a <- io $ evalFeature ftr
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either (\es -> io $ warnMissing' es >> return def) (iof . io) a
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applyFeature_ :: MonadIO m => (m () -> m ()) -> Feature (IO ()) -> m ()
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applyFeature_ iof = applyFeature iof ()
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executeFeature :: MonadIO m => a -> Feature (IO a) -> m a
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executeFeature = applyFeature id
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executeFeature_ :: Feature (IO ()) -> IO ()
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executeFeature_ = executeFeature ()
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whenSatisfied :: Monad m => MaybeAction (m ()) -> m ()
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whenSatisfied = flip ifSatisfied skip
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ifSatisfied :: MaybeAction a -> a -> a
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ifSatisfied (Right x) _ = x
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ifSatisfied _ alt = alt
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--------------------------------------------------------------------------------
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-- | Dependencies
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data Dependency = Executable String
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| AccessiblePath FilePath Bool Bool
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| IOTest (IO (Maybe String))
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| DBusEndpoint Bus Endpoint
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| DBusBus Bus
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| Systemd UnitType String
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data UnitType = SystemUnit | UserUnit deriving (Eq, Show)
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data DBusMember = Method_ MemberName
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| Signal_ MemberName
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| Property_ String
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deriving (Eq, Show)
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data Bus = Bus Bool BusName deriving (Eq, Show)
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data Endpoint = Endpoint ObjectPath InterfaceName DBusMember deriving (Eq, Show)
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pathR :: String -> Dependency
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pathR n = AccessiblePath n True False
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pathW :: String -> Dependency
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pathW n = AccessiblePath n False True
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pathRW :: String -> Dependency
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pathRW n = AccessiblePath n True True
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systemUnit :: String -> Dependency
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systemUnit = Systemd SystemUnit
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userUnit :: String -> Dependency
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userUnit = Systemd UserUnit
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--------------------------------------------------------------------------------
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-- | Dependency evaluation
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--
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-- Test the existence of dependencies and return either Nothing (which actually
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-- means success) or Just <error message>.
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evalDependency :: Dependency -> IO (Maybe String)
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evalDependency (Executable n) = exeSatisfied n
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evalDependency (IOTest t) = t
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evalDependency (Systemd t n) = unitSatisfied t n
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evalDependency (AccessiblePath p r w) = pathSatisfied p r w
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evalDependency (DBusEndpoint b e) = endpointSatisfied b e
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evalDependency (DBusBus b) = busSatisfied b
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exeSatisfied :: String -> IO (Maybe String)
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exeSatisfied x = do
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r <- findExecutable x
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return $ case r of
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(Just _) -> Nothing
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_ -> Just $ "executable '" ++ x ++ "' not found"
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unitSatisfied :: UnitType -> String -> IO (Maybe String)
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unitSatisfied u x = do
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(rc, _, _) <- readCreateProcessWithExitCode' (shell cmd) ""
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return $ case rc of
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ExitSuccess -> Nothing
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_ -> Just $ "systemd " ++ unitType u ++ " unit '" ++ x ++ "' not found"
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where
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cmd = fmtCmd "systemctl" $ ["--user" | u == UserUnit] ++ ["status", x]
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unitType SystemUnit = "system"
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unitType UserUnit = "user"
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pathSatisfied :: FilePath -> Bool -> Bool -> IO (Maybe String)
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pathSatisfied p testread testwrite = do
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res <- getPermissionsSafe p
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let msg = permMsg res
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return msg
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where
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testPerm False _ _ = Nothing
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testPerm True f r = Just $ f r
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permMsg NotFoundError = Just "file not found"
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permMsg PermError = Just "could not get permissions"
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permMsg (PermResult r) =
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case (testPerm testread readable r, testPerm testwrite writable r) of
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(Just False, Just False) -> Just "file not readable or writable"
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(Just False, _) -> Just "file not readable"
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(_, Just False) -> Just "file not writable"
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_ -> Nothing
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introspectInterface :: InterfaceName
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introspectInterface = interfaceName_ "org.freedesktop.DBus.Introspectable"
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introspectMethod :: MemberName
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introspectMethod = memberName_ "Introspect"
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-- TODO this belongs somewhere else, IDK where tho for now
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callMethod :: Client -> BusName -> ObjectPath -> InterfaceName -> MemberName
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-> IO (Either String [Variant])
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callMethod client bus path iface mem = do
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reply <- call client (methodCall path iface mem)
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{ methodCallDestination = Just bus }
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return $ bimap methodErrorMessage methodReturnBody reply
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busSatisfied :: Bus -> IO (Maybe String)
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busSatisfied (Bus usesystem bus) = do
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client <- if usesystem then connectSystem else connectSession
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ret <- callMethod client queryBus queryPath queryIface queryMem
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disconnect client
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return $ case ret of
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Left e -> Just e
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Right b -> let ns = bodyGetNames b in
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if bus' `elem` ns then Nothing
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else Just $ unwords ["name", singleQuote bus', "not found on dbus"]
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where
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bus' = formatBusName bus
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queryBus = busName_ "org.freedesktop.DBus"
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queryIface = interfaceName_ "org.freedesktop.DBus"
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queryPath = objectPath_ "/"
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queryMem = memberName_ "ListNames"
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bodyGetNames [v] = fromMaybe [] $ fromVariant v :: [String]
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bodyGetNames _ = []
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endpointSatisfied :: Bus -> Endpoint -> IO (Maybe String)
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endpointSatisfied (Bus u bus) (Endpoint objpath iface mem) = do
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client <- if u then connectSystem else connectSession
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ret <- callMethod client bus objpath introspectInterface introspectMethod
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disconnect client
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return $ case ret of
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Left e -> Just e
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Right body -> procBody body
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where
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procBody body = let res = findMem =<< I.parseXML objpath =<< fromVariant
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=<< listToMaybe body in
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case res of
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Just True -> Nothing
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_ -> Just $ fmtMsg' mem
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findMem = fmap (matchMem mem)
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. find (\i -> I.interfaceName i == iface)
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. I.objectInterfaces
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matchMem (Method_ n) = elemMember n I.methodName I.interfaceMethods
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matchMem (Signal_ n) = elemMember n I.signalName I.interfaceSignals
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matchMem (Property_ n) = elemMember n I.propertyName I.interfaceProperties
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elemMember n fname fmember = elem n . fmap fname . fmember
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fmtMem (Method_ n) = "method " ++ singleQuote (formatMemberName n)
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fmtMem (Signal_ n) = "signal " ++ singleQuote (formatMemberName n)
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fmtMem (Property_ n) = "property " ++ singleQuote n
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fmtMsg' m = unwords
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[ "could not find"
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, fmtMem m
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, "on interface"
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, singleQuote $ formatInterfaceName iface
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, "on bus"
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, formatBusName bus
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]
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--------------------------------------------------------------------------------
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-- | Logging functions
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warnMissing :: [MaybeAction a] -> IO ()
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warnMissing xs = warnMissing' $ concat $ [ m | (Left m) <- xs ]
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warnMissing' :: [String] -> IO ()
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warnMissing' = mapM_ putStrLn
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fmtMsg :: String -> String -> String -> String
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fmtMsg procName level msg = unwords [bracket procName, bracket level, msg]
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where
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bracket s = "[" ++ s ++ "]"
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