{-# LINE 1 "libraries/base/System/Environment/ExecutablePath.hsc" #-}
{-# LANGUAGE Safe #-}
{-# LANGUAGE CPP #-}

-----------------------------------------------------------------------------
-- |
-- Module      :  System.Environment.ExecutablePath
-- Copyright   :  (c) The University of Glasgow 2001
-- License     :  BSD-style (see the file libraries/base/LICENSE)
--
-- Maintainer  :  libraries@haskell.org
-- Stability   :  provisional
-- Portability :  portable
--
-- Function to retrieve the absolute filepath of the current executable.
--
-- @since 4.6.0.0
-----------------------------------------------------------------------------

module System.Environment.ExecutablePath ( getExecutablePath ) where

-- The imports are purposely kept completely disjoint to prevent edits
-- to one OS implementation from breaking another.


{-# LINE 25 "libraries/base/System/Environment/ExecutablePath.hsc" #-}
import Data.Word
import Foreign.C
import Foreign.Marshal.Alloc
import Foreign.Ptr
import Foreign.Storable
import System.Posix.Internals

{-# LINE 60 "libraries/base/System/Environment/ExecutablePath.hsc" #-}

-- The exported function is defined outside any if-guard to make sure
-- every OS implements it with the same type.

-- | Returns the absolute pathname of the current executable.
--
-- Note that for scripts and interactive sessions, this is the path to
-- the interpreter (e.g. ghci.)
--
-- Since base 4.11.0.0, 'getExecutablePath' resolves symlinks on Windows.
-- If an executable is launched through a symlink, 'getExecutablePath'
-- returns the absolute path of the original executable.
--
-- @since 4.6.0.0
getExecutablePath :: IO FilePath

--------------------------------------------------------------------------------
-- Mac OS X


{-# LINE 80 "libraries/base/System/Environment/ExecutablePath.hsc" #-}

type UInt32 = Word32

foreign import ccall unsafe "mach-o/dyld.h _NSGetExecutablePath"
    c__NSGetExecutablePath :: CString -> Ptr UInt32 -> IO CInt

-- | Returns the path of the main executable. The path may be a
-- symbolic link and not the real file.
--
-- See dyld(3)
_NSGetExecutablePath :: IO FilePath
_NSGetExecutablePath :: IO FilePath
_NSGetExecutablePath =
    forall a b. Int -> (Ptr a -> IO b) -> IO b
allocaBytes Int
1024 forall a b. (a -> b) -> a -> b
$ \ Ptr CChar
buf ->  -- PATH_MAX is 1024 on OS X
    forall a b. Storable a => (Ptr a -> IO b) -> IO b
alloca forall a b. (a -> b) -> a -> b
$ \ Ptr UInt32
bufsize -> do
        forall a. Storable a => Ptr a -> a -> IO ()
poke Ptr UInt32
bufsize UInt32
1024
        CInt
status <- Ptr CChar -> Ptr UInt32 -> IO CInt
c__NSGetExecutablePath Ptr CChar
buf Ptr UInt32
bufsize
        if CInt
status forall a. Eq a => a -> a -> Bool
== CInt
0
            then Ptr CChar -> IO FilePath
peekFilePath Ptr CChar
buf
            else do Int
reqBufsize <- forall a b. (Integral a, Num b) => a -> b
fromIntegral forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
`fmap` forall a. Storable a => Ptr a -> IO a
peek Ptr UInt32
bufsize
                    forall a b. Int -> (Ptr a -> IO b) -> IO b
allocaBytes Int
reqBufsize forall a b. (a -> b) -> a -> b
$ \ Ptr CChar
newBuf -> do
                        CInt
status2 <- Ptr CChar -> Ptr UInt32 -> IO CInt
c__NSGetExecutablePath Ptr CChar
newBuf Ptr UInt32
bufsize
                        if CInt
status2 forall a. Eq a => a -> a -> Bool
== CInt
0
                             then Ptr CChar -> IO FilePath
peekFilePath Ptr CChar
newBuf
                             else forall a. FilePath -> a
errorWithoutStackTrace FilePath
"_NSGetExecutablePath: buffer too small"

foreign import ccall unsafe "stdlib.h realpath"
    c_realpath :: CString -> CString -> IO CString

-- | Resolves all symbolic links, extra \/ characters, and references
-- to \/.\/ and \/..\/. Returns an absolute pathname.
--
-- See realpath(3)
realpath :: FilePath -> IO FilePath
realpath :: FilePath -> IO FilePath
realpath FilePath
path =
    forall a. FilePath -> (Ptr CChar -> IO a) -> IO a
withFilePath FilePath
path forall a b. (a -> b) -> a -> b
$ \ Ptr CChar
fileName ->
    forall a b. Int -> (Ptr a -> IO b) -> IO b
allocaBytes Int
1024 forall a b. (a -> b) -> a -> b
$ \ Ptr CChar
resolvedName -> do
        Ptr CChar
_ <- forall a. FilePath -> IO (Ptr a) -> IO (Ptr a)
throwErrnoIfNull FilePath
"realpath" forall a b. (a -> b) -> a -> b
$ Ptr CChar -> Ptr CChar -> IO (Ptr CChar)
c_realpath Ptr CChar
fileName Ptr CChar
resolvedName
        Ptr CChar -> IO FilePath
peekFilePath Ptr CChar
resolvedName

getExecutablePath :: IO FilePath
getExecutablePath = IO FilePath
_NSGetExecutablePath forall (m :: * -> *) a b. Monad m => m a -> (a -> m b) -> m b
>>= FilePath -> IO FilePath
realpath

--------------------------------------------------------------------------------
-- Linux


{-# LINE 300 "libraries/base/System/Environment/ExecutablePath.hsc" #-}