factor out convertToWindowsNativeNamespace into its own module

Gonna use this more widely.

Sponsored-by: Dartmouth College's Datalad project
This commit is contained in:
Joey Hess 2023-03-01 13:14:55 -04:00
parent 9417bdab14
commit 3c08af0da1
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3 changed files with 47 additions and 30 deletions

44
Utility/Path/Windows.hs Normal file
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{- Windows paths
-
- Copyright 2022-2023 Joey Hess <id@joeyh.name>
-
- License: BSD-2-clause
-}
{-# LANGUAGE OverloadedStrings #-}
{-# OPTIONS_GHC -fno-warn-tabs #-}
module Utility.Path.Windows (
convertToWindowsNativeNamespace
) where
import Utility.Path.AbsRel
import System.FilePath.ByteString (RawFilePath)
import qualified Data.ByteString as B
import qualified System.FilePath.Windows.ByteString as P
{- Convert a filepath to use Windows's native namespace.
- This avoids filesystem length limits.
-
- This is similar to the way base converts filenames on windows,
- but as that is implemented in C (create_device_name) and not
- exported, it cannot be used here. Several edge cases are not handled,
- including network shares and dos short paths.
-}
convertToWindowsNativeNamespace :: RawFilePath -> IO RawFilePath
convertToWindowsNativeNamespace f
| win32_dev_namespace `B.isPrefixOf` f = return f
| win32_file_namespace `B.isPrefixOf` f = return f
| nt_device_namespace `B.isPrefixOf` f = return f
| otherwise = do
-- Make absolute because any '.' and '..' in the path
-- will not be resolved once it's converted.
p <- absPath f
-- Normalize slashes.
let p' = P.normalise p
return (win32_file_namespace <> p')
where
win32_dev_namespace = "\\\\.\\"
win32_file_namespace = "\\\\?\\"
nt_device_namespace = "\\Device\\"