ghcup-hs/lib/GHCup/Utils/File/Common.hs
2021-06-05 21:01:01 +02:00

107 lines
3.1 KiB
Haskell

{-# LANGUAGE QuasiQuotes #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE TemplateHaskell #-}
{-# LANGUAGE ViewPatterns #-}
module GHCup.Utils.File.Common where
import GHCup.Utils.Prelude
import Control.Monad.Extra
import Control.Monad.Reader
import Data.Maybe
import Data.String.Interpolate
import GHC.IO.Exception
import Optics hiding ((<|), (|>))
import System.Directory
import System.FilePath
import Text.PrettyPrint.HughesPJClass hiding ( (<>) )
import Text.Regex.Posix
import qualified Data.ByteString.Lazy as BL
data ProcessError = NonZeroExit Int FilePath [String]
| PTerminated FilePath [String]
| PStopped FilePath [String]
| NoSuchPid FilePath [String]
deriving Show
instance Pretty ProcessError where
pPrint (NonZeroExit e exe args) =
text [i|Process "#{exe}" with arguments #{args} failed with exit code #{e}.|]
pPrint (PTerminated exe args) =
text [i|Process "#{exe}" with arguments #{args} terminated.|]
pPrint (PStopped exe args) =
text [i|Process "#{exe}" with arguments #{args} stopped.|]
pPrint (NoSuchPid exe args) =
text [i|Could not find PID for process running "#{exe}" with arguments #{args}.|]
data CapturedProcess = CapturedProcess
{ _exitCode :: ExitCode
, _stdOut :: BL.ByteString
, _stdErr :: BL.ByteString
}
deriving (Eq, Show)
makeLenses ''CapturedProcess
-- | Search for a file in the search paths.
--
-- Catches `PermissionDenied` and `NoSuchThing` and returns `Nothing`.
searchPath :: [FilePath] -> FilePath -> IO (Maybe FilePath)
searchPath paths needle = go paths
where
go [] = pure Nothing
go (x : xs) =
hideErrorDefM [InappropriateType, PermissionDenied, NoSuchThing] (go xs)
$ do
contents <- listDirectory x
findM (isMatch x) contents >>= \case
Just _ -> pure $ Just (x </> needle)
Nothing -> go xs
isMatch basedir p = do
if p == needle
then isExecutable (basedir </> needle)
else pure False
isExecutable :: FilePath -> IO Bool
isExecutable file = executable <$> getPermissions file
-- | Check wether a binary is shadowed by another one that comes before
-- it in PATH. Returns the path to said binary, if any.
isShadowed :: FilePath -> IO (Maybe FilePath)
isShadowed p = do
let dir = takeDirectory p
let fn = takeFileName p
spaths <- liftIO getSearchPath
if dir `elem` spaths
then do
let shadowPaths = takeWhile (/= dir) spaths
searchPath shadowPaths fn
else pure Nothing
-- | Check whether the binary is in PATH. This returns only `True`
-- if the directory containing the binary is part of PATH.
isInPath :: FilePath -> IO Bool
isInPath p = do
let dir = takeDirectory p
let fn = takeFileName p
spaths <- liftIO getSearchPath
if dir `elem` spaths
then isJust <$> searchPath [dir] fn
else pure False
findFiles :: FilePath -> Regex -> IO [FilePath]
findFiles path regex = do
contents <- listDirectory path
pure $ filter (match regex) contents