{-# LINE 1 "System/Posix/Env.hsc" #-}{-# LANGUAGE CApiFFI #-}{-# LANGUAGE Safe #-}------------------------------------------------------------------------------- |-- Module : System.Posix.Env-- Copyright : (c) The University of Glasgow 2002-- License : BSD-style (see the file libraries/base/LICENSE)---- Maintainer : libraries@haskell.org-- Stability : provisional-- Portability : non-portable (requires POSIX)---- POSIX environment support-------------------------------------------------------------------------------moduleSystem.Posix.Env(getEnv ,getEnvDefault ,getEnvironmentPrim ,getEnvironment ,setEnvironment ,putEnv ,setEnv ,unsetEnv ,clearEnv )whereimportForeignhiding(void)importForeign.C.Error(throwErrnoIfMinus1_)importForeign.C.TypesimportForeign.C.StringimportControl.MonadimportData.Maybe(fromMaybe)importSystem.Posix.InternalsimportqualifiedSystem.Posix.Env.Internal asInternal-- |'getEnv' looks up a variable in the environment.getEnv ::String{- ^ variable name -}->IO(MaybeString){- ^ variable value -}getEnv :: String -> IO (Maybe String)
getEnv String
name =doCString
litstring <-String -> (CString -> IO CString) -> IO CString
forall a. String -> (CString -> IO a) -> IO a
withFilePathString
name CString -> IO CString
c_getenv ifCString
litstring CString -> CString -> Bool
forall a. Eq a => a -> a -> Bool
/=CString
forall a. Ptr a
nullPtrthenString -> Maybe String
forall a. a -> Maybe a
Just(String -> Maybe String) -> IO String -> IO (Maybe String)
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$>CString -> IO String
peekFilePathCString
litstring elseMaybe String -> IO (Maybe String)
forall a. a -> IO a
forall (m :: * -> *) a. Monad m => a -> m a
returnMaybe String
forall a. Maybe a
Nothing-- |'getEnvDefault' is a wrapper around 'getEnv' where the-- programmer can specify a fallback if the variable is not found-- in the environment.getEnvDefault ::String{- ^ variable name -}->String{- ^ fallback value -}->IOString{- ^ variable value or fallback value -}getEnvDefault :: String -> String -> IO String
getEnvDefault String
name String
fallback =String -> Maybe String -> String
forall a. a -> Maybe a -> a
fromMaybeString
fallback (Maybe String -> String) -> IO (Maybe String) -> IO String
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$>String -> IO (Maybe String)
getEnv String
name foreignimportccallunsafe"getenv"c_getenv ::CString->IOCStringgetEnvironmentPrim ::IO[String]getEnvironmentPrim :: IO [String]
getEnvironmentPrim =IO [CString]
Internal.getEnvironmentPrim IO [CString] -> ([CString] -> IO [String]) -> IO [String]
forall a b. IO a -> (a -> IO b) -> IO b
forall (m :: * -> *) a b. Monad m => m a -> (a -> m b) -> m b
>>=(CString -> IO String) -> [CString] -> IO [String]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
forall (m :: * -> *) a b. Monad m => (a -> m b) -> [a] -> m [b]
mapMCString -> IO String
peekFilePath-- |'getEnvironment' retrieves the entire environment as a-- list of @(key,value)@ pairs.getEnvironment ::IO[(String,String)]{- ^ @[(key,value)]@ -}getEnvironment :: IO [(String, String)]
getEnvironment =do[String]
env <-IO [String]
getEnvironmentPrim [(String, String)] -> IO [(String, String)]
forall a. a -> IO a
forall (m :: * -> *) a. Monad m => a -> m a
return([(String, String)] -> IO [(String, String)])
-> [(String, String)] -> IO [(String, String)]
forall a b. (a -> b) -> a -> b
$(String -> (String, String)) -> [String] -> [(String, String)]
forall a b. (a -> b) -> [a] -> [b]
map((String, String) -> (String, String)
dropEq ((String, String) -> (String, String))
-> (String -> (String, String)) -> String -> (String, String)
forall b c a. (b -> c) -> (a -> b) -> a -> c
.((Char -> Bool) -> String -> (String, String)
forall a. (a -> Bool) -> [a] -> ([a], [a])
break(Char -> Char -> Bool
forall a. Eq a => a -> a -> Bool
(==)Char
'=')))[String]
env wheredropEq :: (String, String) -> (String, String)
dropEq (String
x ,Char
'=':String
ys )=(String
x ,String
ys )dropEq (String
x ,String
_)=String -> (String, String)
forall a. HasCallStack => String -> a
error(String -> (String, String)) -> String -> (String, String)
forall a b. (a -> b) -> a -> b
$String
"getEnvironment: insane variable "String -> String -> String
forall a. [a] -> [a] -> [a]
++String
x -- |'setEnvironment' resets the entire environment to the given list of-- @(key,value)@ pairs.setEnvironment ::[(String,String)]{- ^ @[(key,value)]@ -}->IO()setEnvironment :: [(String, String)] -> IO ()
setEnvironment [(String, String)]
env =doIO ()
clearEnv [(String, String)] -> ((String, String) -> IO ()) -> IO ()
forall (t :: * -> *) (m :: * -> *) a b.
(Foldable t, Monad m) =>
t a -> (a -> m b) -> m ()
forM_[(String, String)]
env (((String, String) -> IO ()) -> IO ())
-> ((String, String) -> IO ()) -> IO ()
forall a b. (a -> b) -> a -> b
$\(String
key ,String
value )->String -> String -> Bool -> IO ()
setEnv String
key String
value Bool
True{-overwrite-}-- |The 'unsetEnv' function deletes all instances of the variable name-- from the environment.unsetEnv ::String{- ^ variable name -}->IO(){-# LINE 95 "System/Posix/Env.hsc" #-}unsetEnv :: String -> IO ()
{-# LINE 96 "System/Posix/Env.hsc" #-} unsetEnvname=withFilePathname$\s->throwErrnoIfMinus1_"unsetenv"(c_unsetenvs)-- POSIX.1-2001 compliant unsetenv(3)foreignimportcapiunsafe"HsUnix.h unsetenv"c_unsetenv ::CString->IOCInt{-# LINE 109 "System/Posix/Env.hsc" #-}{-# LINE 112 "System/Posix/Env.hsc" #-}-- |'putEnv' function takes an argument of the form @name=value@-- and is equivalent to @setEnv(key,value,True{-overwrite-})@.putEnv ::String{- ^ "key=value" -}->IO()putEnv :: String -> IO ()
putEnv String
keyvalue =doCString
s <-String -> IO CString
newFilePathString
keyvalue -- Do not free `s` after calling putenv.-- According to SUSv2, the string passed to putenv-- becomes part of the environment. #7342String -> IO CInt -> IO ()
forall a. (Eq a, Num a) => String -> IO a -> IO ()
throwErrnoIfMinus1_String
"putenv"(CString -> IO CInt
c_putenv CString
s )foreignimportccallunsafe"putenv"c_putenv ::CString->IOCInt{- |The 'setEnv' function inserts or resets the environment variable name in
 the current environment list. If the variable @name@ does not exist in the
 list, it is inserted with the given value. If the variable does exist,
 the argument @overwrite@ is tested; if @overwrite@ is @False@, the variable is
 not reset, otherwise it is reset to the given value.
-}setEnv ::String{- ^ variable name -}->String{- ^ variable value -}->Bool{- ^ overwrite -}->IO(){-# LINE 139 "System/Posix/Env.hsc" #-}setEnvkeyvalueovrwrt=dowithFilePathkey$\keyP->withFilePathvalue$\valueP->throwErrnoIfMinus1_"setenv"$c_setenvkeyPvalueP(fromIntegral(fromEnumovrwrt))foreignimportccallunsafe"setenv"c_setenv ::CString->CString->CInt->IOCInt{-# LINE 155 "System/Posix/Env.hsc" #-}-- |The 'clearEnv' function clears the environment of all name-value pairs.clearEnv ::IO()clearEnv :: IO ()
{-# LINE 159 "System/Posix/Env.hsc" #-} clearEnv=voidc_clearenvforeignimportccallunsafe"clearenv"c_clearenv ::IOInt{-# LINE 170 "System/Posix/Env.hsc" #-}