{-# LANGUAGE DataKinds #-}
{-|
Module : System.XDG
Description : XDG Basedir functions
These functions implement the [XDG Base Directory Specification](https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html).
When an environment variable is missing that must be defined, they will
raise a `MissingEnv` exception. This applies to @$HOME@ and @$XDG_RUNTIME_DIR@.
-}
module System.XDG where
import Data.ByteString.Lazy ( ByteString )
import Data.Either ( fromRight )
import Polysemy
import Polysemy.Error ( runError )
import Polysemy.Operators
import System.XDG.Env
import System.XDG.Error
import System.XDG.FileSystem
import qualified System.XDG.Internal as In
{-| Returns the content of @$XDG_DATA_HOME@ or its default value. -}
getDataHome :: IO FilePath
getDataHome = In.runXDGIO In.getDataHome
{-| Returns the content of @$XDG_CONFIG_HOME@ or its default value. -}
getConfigHome :: IO FilePath
getConfigHome = In.runXDGIO In.getConfigHome
{-| Returns the content of @$XDG_STATE_HOME@ or its default value. -}
getStateHome :: IO FilePath
getStateHome = In.runXDGIO In.getStateHome
{-| Returns the content of @$XDG_CACHE_HOME@ or its default value. -}
getCacheHome :: IO FilePath
getCacheHome = In.runXDGIO In.getCacheHome
{-| Returns the content of @$XDG_RUNTIME_DIR@. -}
getRuntimeDir :: IO FilePath
getRuntimeDir = In.runXDGIO In.getRuntimeDir
{-| Returns the list of data dirs taken from @$XDG_DATA_HOME@ and
@$XDG_DATA_DIRS@ or their default values. -}
getDataDirs :: IO [FilePath]
getDataDirs = In.runXDGIO In.getDataDirs
{-| Returns the content of the first readable file in the data dirs if there is one.
It will try the files in order of decreasing imporance.
To read @$XDG_DATA_DIRS\/subdir\/filename@:
@
> readDataFile "subdir/filename"
@
-}
readDataFile :: FilePath -> IO (Maybe ByteString)
readDataFile file = In.runXDGIO $ In.maybeRead $ In.readDataFile file
{-| Parse all readable data files into a monoid and append them.
The append operation will operate left to right in the order of decreasing importance. -}
readData :: Monoid b => (ByteString -> b) -> FilePath -> IO b
readData parse file = In.runXDGIO $ In.readData parse file
{-| Returns the list of config dirs taken from @$XDG_CONFIG_HOME@ and
@$XDG_CONFIG_DIRS@ or their default values. -}
getConfigDirs :: IO [FilePath]
getConfigDirs = In.runXDGIO In.getConfigDirs
{-| Returns the content of the first readable file in the config dirs if there is one.
It will try the files in order of decreasing imporance.
To read @$XDG_CONFIG_DIRS\/subdir\/filename@:
@
> readConfigFile "subdir/filename"
@
-}
readConfigFile :: FilePath -> IO (Maybe ByteString)
readConfigFile file = In.runXDGIO $ In.maybeRead $ In.readConfigFile file
{-| Parse all readable config files into a monoid and append them.
The append operation will operate left to right in the order of decreasing importance. -}
readConfig :: Monoid b => (ByteString -> b) -> FilePath -> IO b
readConfig parse file = In.runXDGIO $ In.readConfig parse file
{-| Returns the content of the cache file if it exists.
@
> readCacheFile "subdir/filename"
@
-}
readCacheFile :: FilePath -> IO (Maybe ByteString)
readCacheFile file = In.runXDGIO $ In.maybeRead $ In.readCacheFile file
{-| Returns the content of the state file if it exists.
@
> readStateFile "subdir/filename"
@
-}
readStateFile :: FilePath -> IO (Maybe ByteString)
readStateFile file = In.runXDGIO $ In.maybeRead $ In.readStateFile file
{-| Returns the content of the runtime file if it exists.
@
> readRuntimeFile "subdir/filename"
@
-}
readRuntimeFile :: FilePath -> IO (Maybe ByteString)
readRuntimeFile file = In.runXDGIO $ In.maybeRead $ In.readStateFile file