{- |

Module : ./Common/FileType.hs

Description : checking the file type

Copyright : (c) C. Maeder, DFKI 2014

License : GPLv2 or higher, see LICENSE.txt

Maintainer : Christian.Maeder@dfki.de

Stability : provisional

Portability : portable

check the file content by using the unix tool file

-}

module Common.FileType (getMagicFileType, getChecksum) where

import System.Exit

import Common.Utils

import Common.Result

import Common.ResultT

import Data.List

import Data.Maybe

getChecksum :: FilePath -> ResultT IO String

getChecksum fn = ResultT $ do

ckprg <- getEnvDef "HETS_CHECKSUM" "shasum -a 256"

case words ckprg of -- no support for options with spaces

[] -> return $ fail "set HETS_CHECKSUM to a proper command"

cmd : args -> do

(ex, out, err) <- executeProcess cmd (args ++ [fn]) ""

return $ case (ex, map words $ lines out) of

(ExitSuccess, (h : _) : _) | null err ->

justHint h $ h ++ " " ++ fn

_ -> fail $ "could not determine checksum: "

++ shows ex "\n" ++ out

++ if null err then "" else "\nerror\n" ++ err

getMagicFileType :: Maybe String -> FilePath -> ResultT IO String

getMagicFileType mp fn = ResultT $ do

res <- runResultT $ getFileType Nothing (Just "--mime-encoding") fn

runResultT $ case maybeResult res of

Just s -> do

liftR $ justHint () $ "mime-encoding: " ++ s

if any (`isInfixOf` s) ["binary", "unknown"]

then do

liftR $ justWarn () $ "no support for " ++ s ++ " file: " ++ fn

getFileType Nothing mp fn

else getMagicFileTypeAux mp fn

_ -> liftR res

getMagicFileTypeAux :: Maybe String -> FilePath -> ResultT IO String

getMagicFileTypeAux pm fn = ResultT $ do

magic <- getEnvDef "HETS_MAGIC" ""

res <- if null magic then return $ fail "null magic" else

runResultT $ getFileType Nothing Nothing magic

runResultT $ case maybeResult res of

Just s | isInfixOf "magic" s -> getFileType (Just magic) pm fn

_ -> do

liftR $ justWarn () "set HETS_MAGIC to a proper magic file"

getFileType Nothing pm fn

getFileType :: Maybe FilePath -> Maybe String -> FilePath -> ResultT IO String

getFileType mmf mp fn = ResultT $ do

(ex, out, err) <- executeProcessWithEnvironment "file"

(maybeToList mp ++ ["--brief", fn]) ""

$ maybe [] (\ mf -> [("MAGIC", mf)]) mmf

let unexp = "unexpected file type "

return $ case (ex, lines out) of

(ExitSuccess, ls) -> if null err then case ls of

[l] -> return l

_ -> fail $ unexp ++ "output:\n" ++ out

else fail $ unexp ++ "error:\n" ++ err

_ -> fail $ unexp ++ "exit code: " ++ show ex