110 lines
3.7 KiB
Haskell
110 lines
3.7 KiB
Haskell
module GHCup.File where
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import Data.ByteString
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import qualified Data.ByteString.Lazy as L
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import Data.Char
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import Data.Maybe
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import HPath
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import HPath.IO
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import Streamly.ByteString
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import Streamly
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import System.Posix.FilePath hiding ( (</>) )
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import Data.Foldable
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import Control.Monad
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import Control.Exception.Safe
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import Data.Functor
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import System.Posix.Files.ByteString
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import System.IO
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import System.Posix.IO.ByteString
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hiding ( openFd )
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import qualified System.Posix.Process.ByteString
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as SPPB
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import System.Posix.Types
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import qualified Streamly.Internal.Memory.ArrayStream
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as AS
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import qualified Streamly.FileSystem.Handle as FH
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import qualified Streamly.Internal.Data.Unfold as SU
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import qualified Streamly.Prelude as S
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import System.Exit
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import qualified Streamly.Data.Fold as FL
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import Data.ByteString.Builder
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import Foreign.C.Error
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import GHCup.Prelude
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-- |Checks whether a file is executable. Follows symlinks.
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--
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-- Only eACCES, eROFS, eTXTBSY, ePERM are catched (and return False).
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--
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-- Throws:
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--
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-- - `NoSuchThing` if the file does not exist
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--
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-- Note: calls `access`
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isExecutable :: Path b -> IO Bool
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isExecutable p = fileAccess (toFilePath p) False False True
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readFd :: Fd -> IO L.ByteString
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readFd fd = do
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handle' <- fdToHandle fd
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let stream =
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(S.unfold (SU.finally hClose FH.readChunks) handle')
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>>= arrayToByteString
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toLazyByteString <$> S.fold FL.mconcat (fmap byteString stream)
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-- | Read the lines of a file into a stream. The stream holds
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-- a file handle as a resource and will close it once the stream
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-- terminates (either through exception or because it's drained).
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readFileLines :: Path b -> IO (SerialT IO ByteString)
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readFileLines p = do
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stream <- readFileStream p
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pure
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. (>>= arrayToByteString)
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. AS.splitOn (fromIntegral $ ord '\n')
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. (>>= byteStringToArray)
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$ stream
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-- | Find the given executable by searching all *absolute* PATH components.
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-- Relative paths in PATH are ignored.
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--
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-- This shouldn't throw IO exceptions, unless getting the environment variable
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-- PATH does.
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findExecutable :: RelC r => Path r -> IO (Maybe (Path Abs))
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findExecutable ex = do
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sPaths <- fmap catMaybes . (fmap . fmap) parseAbs $ getSearchPath
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-- We don't want exceptions to mess up our result. If we can't
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-- figure out if a file exists, then treat it as a negative result.
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asum $ fmap (handleIO (\_ -> pure Nothing)) $ fmap
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-- asum for short-circuiting behavior
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(\s -> (isExecutable (s </> ex) >>= guard) $> (Just (s </> ex)))
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sPaths
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-- | Execute the given command and collect the stdout and the exit code.
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executeOut :: Path Fn -- ^ command as filename, e.g. 'ls'
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-> [ByteString] -- ^ arguments to the command
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-> IO (Maybe (L.ByteString, ExitCode)) -- ^ fst of the tuple is the stdout
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executeOut path args = withFnPath path $ \fp -> do
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(parentRead, childWrite) <- createPipe
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pid <- SPPB.forkProcess $ do
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whileM_
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(dupTo childWrite stdOutput)
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(\r ->
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getErrno >>= \e -> pure $ r == fromIntegral (-1 :: Int) && e == eINTR
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)
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closeFd childWrite
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closeFd parentRead
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closeFd stdInput
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SPPB.executeFile fp True args Nothing
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closeFd childWrite
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SPPB.getProcessStatus True True pid >>= \case
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-- readE will take care of closing the fd
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Just (SPPB.Exited es) -> readFd parentRead <&> Just . (, es)
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_ -> closeFd parentRead $> Nothing
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