Merge pull request #10988 from haskell/avoid-init-and-last

Avoid partial functions Data.List.init and Data.List.last

Author: mergify[bot]

Cabal/src/Distribution/Compat/Internal/TempFile.hs

@@ -12,113 +12,18 @@ import Distribution.Compat.Exception
 
 import System.FilePath ((</>))
 
-import System.IO (Handle, openBinaryTempFile, openTempFile)
-#if defined(__IO_MANAGER_WINIO__)
-import System.IO              (openBinaryTempFileWithDefaultPermissions)
-import System.Posix.Internals (c_getpid)
-#else
-import Control.Exception      (onException)
-import Data.Bits              ((.|.))
-import Foreign.C              (CInt, eEXIST, getErrno, errnoToIOError)
-import GHC.IO.Handle.FD       (fdToHandle)
-import System.Posix.Internals (c_getpid, c_open, c_close, o_EXCL, o_BINARY, withFilePath,
-                               o_CREAT, o_RDWR, o_NONBLOCK, o_NOCTTY)
-#endif
-
+import System.IO (Handle, openBinaryTempFile, openBinaryTempFileWithDefaultPermissions, openTempFile)
 import System.IO.Error (isAlreadyExistsError)
+import System.Posix.Internals (c_getpid)
 
 #if defined(mingw32_HOST_OS) || defined(ghcjs_HOST_OS)
 import System.Directory       ( createDirectory )
 #else
 import qualified System.Posix
 #endif
 
--- ------------------------------------------------------------
-
--- * temporary files
-
--- ------------------------------------------------------------
-
--- This is here for Haskell implementations that do not come with
--- System.IO.openTempFile. This includes nhc-1.20, hugs-2006.9.
--- TODO: This file should probably be removed.
-
--- This is a copy/paste of the openBinaryTempFile definition, but
--- it uses 666 rather than 600 for the permissions. Newer versions
--- of base have a new function with this behavior which we use on
--- Windows when the new IO manager is used.
 openNewBinaryFile :: FilePath -> String -> IO (FilePath, Handle)
-openNewBinaryFile dir template = do
-
--- This method can't be used under WINIO. Also the current implementation has
--- thread safety issues depending on which GHC is used.  On newer GHC's let's
--- use the built in one.
-#if defined(__IO_MANAGER_WINIO__)
-  openBinaryTempFileWithDefaultPermissions dir template
-#else
-  pid <- c_getpid
-  findTempName pid
-  where
-    -- We split off the last extension, so we can use .foo.ext files
-    -- for temporary files (hidden on Unix OSes). Unfortunately we're
-    -- below file path in the hierarchy here.
-    (prefix,suffix) =
-       case break (== '.') $ reverse template of
-         -- First case: template contains no '.'s. Just re-reverse it.
-         (rev_suffix, "")       -> (reverse rev_suffix, "")
-         -- Second case: template contains at least one '.'. Strip the
-         -- dot from the prefix and prepend it to the suffix (if we don't
-         -- do this, the unique number will get added after the '.' and
-         -- thus be part of the extension, which is wrong.)
-         (rev_suffix, '.':rest) -> (reverse rest, '.':reverse rev_suffix)
-         -- Otherwise, something is wrong, because (break (== '.')) should
-         -- always return a pair with either the empty string or a string
-         -- beginning with '.' as the second component.
-         _                      -> error "bug in System.IO.openTempFile"
-
-    oflags = rw_flags .|. o_EXCL .|. o_BINARY
-
-    findTempName x = do
-      fd <- withFilePath filepath $ \ f ->
-              c_open f oflags 0o666
-      if fd < 0
-       then do
-         errno <- getErrno
-         if errno == eEXIST
-           then findTempName (x+1)
-           else ioError (errnoToIOError "openNewBinaryFile" errno Nothing (Just dir))
-       else do
-         -- TODO: We want to tell fdToHandle what the file path is,
-         -- as any exceptions etc will only be able to report the
-         -- FD currently
-         h <- fdToHandle fd `onException` c_close fd
-         return (filepath, h)
-      where
-        filename        = prefix ++ show x ++ suffix
-        filepath        = dir `combine` filename
-
-        -- FIXME: bits copied from System.FilePath
-        combine a b
-                  | null b = a
-                  | null a = b
-                  | last a == pathSeparator = a ++ b
-                  | otherwise = a ++ [pathSeparator] ++ b
-
--- FIXME: Copied from GHC.Handle
-std_flags, output_flags, rw_flags :: CInt
-std_flags    = o_NONBLOCK   .|. o_NOCTTY
-output_flags = std_flags    .|. o_CREAT
-rw_flags     = output_flags .|. o_RDWR
-
--- FIXME: Should use System.FilePath library
-pathSeparator :: Char
-#ifdef mingw32_HOST_OS
-pathSeparator = '\\'
-#else
-pathSeparator = '/'
-#endif
--- /* __IO_MANAGER_WINIO__ */
-#endif
+openNewBinaryFile = openBinaryTempFileWithDefaultPermissions
 
 createTempDirectory :: FilePath -> String -> IO FilePath
 createTempDirectory dir template = do