git-annex/Utility/Directory.hs
2020-03-10 13:24:37 -04:00

232 lines
7.2 KiB
Haskell

{- directory traversal and manipulation
-
- Copyright 2011-2020 Joey Hess <id@joeyh.name>
-
- License: BSD-2-clause
-}
{-# LANGUAGE CPP #-}
{-# LANGUAGE LambdaCase #-}
{-# OPTIONS_GHC -fno-warn-tabs #-}
module Utility.Directory (
module Utility.Directory,
module Utility.SystemDirectory
) where
import System.IO.Error
import Control.Monad
import System.FilePath
import System.PosixCompat.Files
import Control.Applicative
import Control.Monad.IO.Class
import Control.Monad.IfElse
import System.IO.Unsafe (unsafeInterleaveIO)
import System.IO.Error
import Data.Maybe
import Prelude
#ifndef mingw32_HOST_OS
import Utility.SafeCommand
#endif
import Utility.SystemDirectory
import Utility.Path
import Utility.Tmp
import Utility.Exception
import Utility.Monad
import Utility.Applicative
import Utility.PartialPrelude
dirCruft :: FilePath -> Bool
dirCruft "." = True
dirCruft ".." = True
dirCruft _ = False
{- Lists the contents of a directory.
- Unlike getDirectoryContents, paths are not relative to the directory. -}
dirContents :: FilePath -> IO [FilePath]
dirContents d = map (d </>) . filter (not . dirCruft) <$> getDirectoryContents d
{- Gets files in a directory, and then its subdirectories, recursively,
- and lazily.
-
- Does not follow symlinks to other subdirectories.
-
- When the directory does not exist, no exception is thrown,
- instead, [] is returned. -}
dirContentsRecursive :: FilePath -> IO [FilePath]
dirContentsRecursive = dirContentsRecursiveSkipping (const False) True
{- Skips directories whose basenames match the skipdir. -}
dirContentsRecursiveSkipping :: (FilePath -> Bool) -> Bool -> FilePath -> IO [FilePath]
dirContentsRecursiveSkipping skipdir followsubdirsymlinks topdir = go [topdir]
where
go [] = return []
go (dir:dirs)
| skipdir (takeFileName dir) = go dirs
| otherwise = unsafeInterleaveIO $ do
(files, dirs') <- collect [] []
=<< catchDefaultIO [] (dirContents dir)
files' <- go (dirs' ++ dirs)
return (files ++ files')
collect files dirs' [] = return (reverse files, reverse dirs')
collect files dirs' (entry:entries)
| dirCruft entry = collect files dirs' entries
| otherwise = do
let skip = collect (entry:files) dirs' entries
let recurse = collect files (entry:dirs') entries
ms <- catchMaybeIO $ getSymbolicLinkStatus entry
case ms of
(Just s)
| isDirectory s -> recurse
| isSymbolicLink s && followsubdirsymlinks ->
ifM (doesDirectoryExist entry)
( recurse
, skip
)
_ -> skip
{- Gets the directory tree from a point, recursively and lazily,
- with leaf directories **first**, skipping any whose basenames
- match the skipdir. Does not follow symlinks. -}
dirTreeRecursiveSkipping :: (FilePath -> Bool) -> FilePath -> IO [FilePath]
dirTreeRecursiveSkipping skipdir topdir = go [] [topdir]
where
go c [] = return c
go c (dir:dirs)
| skipdir (takeFileName dir) = go c dirs
| otherwise = unsafeInterleaveIO $ do
subdirs <- go []
=<< filterM (isDirectory <$$> getSymbolicLinkStatus)
=<< catchDefaultIO [] (dirContents dir)
go (subdirs++dir:c) dirs
{- Moves one filename to another.
- First tries a rename, but falls back to moving across devices if needed. -}
moveFile :: FilePath -> FilePath -> IO ()
moveFile src dest = tryIO (rename src dest) >>= onrename
where
onrename (Right _) = noop
onrename (Left e)
| isPermissionError e = rethrow
| isDoesNotExistError e = rethrow
| otherwise = viaTmp mv dest ""
where
rethrow = throwM e
mv tmp _ = do
-- copyFile is likely not as optimised as
-- the mv command, so we'll use the command.
--
-- But, while Windows has a "mv", it does not seem very
-- reliable, so use copyFile there.
#ifndef mingw32_HOST_OS
-- If dest is a directory, mv would move the file
-- into it, which is not desired.
whenM (isdir dest) rethrow
ok <- boolSystem "mv" [Param "-f", Param src, Param tmp]
let e' = e
#else
r <- tryIO $ copyFile src tmp
let (ok, e') = case r of
Left err -> (False, err)
Right _ -> (True, e)
#endif
unless ok $ do
-- delete any partial
_ <- tryIO $ removeFile tmp
throwM e'
#ifndef mingw32_HOST_OS
isdir f = do
r <- tryIO $ getFileStatus f
case r of
(Left _) -> return False
(Right s) -> return $ isDirectory s
#endif
{- Removes a file, which may or may not exist, and does not have to
- be a regular file.
-
- Note that an exception is thrown if the file exists but
- cannot be removed. -}
nukeFile :: FilePath -> IO ()
nukeFile file = void $ tryWhenExists go
where
#ifndef mingw32_HOST_OS
go = removeLink file
#else
go = removeFile file
#endif
{- Like createDirectoryIfMissing True, but it will only create
- missing parent directories up to but not including the directory
- in the first parameter.
-
- For example, createDirectoryUnder "/tmp/foo" "/tmp/foo/bar/baz"
- will create /tmp/foo/bar if necessary, but if /tmp/foo does not exist,
- it will throw an exception.
-
- The exception thrown is the same that createDirectory throws if the
- parent directory does not exist.
-
- If the second FilePath is not under the first
- FilePath (or the same as it), it will fail with an exception
- even if the second FilePath's parent directory already exists.
-
- Either or both of the FilePaths can be relative, or absolute.
- They will be normalized as necessary.
-
- Note that, the second FilePath, if relative, is relative to the current
- working directory, not to the first FilePath.
-}
createDirectoryUnder :: FilePath -> FilePath -> IO ()
createDirectoryUnder topdir dir =
createDirectoryUnder' topdir dir createDirectory
createDirectoryUnder'
:: (MonadIO m, MonadCatch m)
=> FilePath
-> FilePath
-> (FilePath -> m ())
-> m ()
createDirectoryUnder' topdir dir0 mkdir = do
p <- liftIO $ relPathDirToFile topdir dir0
let dirs = splitDirectories p
-- Catch cases where the dir is not beneath the topdir.
-- If the relative path between them starts with "..",
-- it's not. And on Windows, if they are on different drives,
-- the path will not be relative.
if headMaybe dirs == Just ".." || isAbsolute p
then liftIO $ ioError $ customerror userErrorType
("createDirectoryFrom: not located in " ++ topdir)
-- If dir0 is the same as the topdir, don't try to create
-- it, but make sure it does exist.
else if null dirs
then liftIO $ unlessM (doesDirectoryExist topdir) $
ioError $ customerror doesNotExistErrorType
"createDirectoryFrom: does not exist"
else createdirs $
map (topdir </>) (reverse (scanl1 (</>) dirs))
where
customerror t s = mkIOError t s Nothing (Just dir0)
createdirs [] = pure ()
createdirs (dir:[]) = createdir dir (liftIO . ioError)
createdirs (dir:dirs) = createdir dir $ \_ -> do
createdirs dirs
createdir dir (liftIO . ioError)
-- This is the same method used by createDirectoryIfMissing,
-- in particular the handling of errors that occur when the
-- directory already exists. See its source for explanation
-- of several subtleties.
createdir dir notexisthandler = tryIO (mkdir dir) >>= \case
Right () -> pure ()
Left e
| isDoesNotExistError e -> notexisthandler e
| isAlreadyExistsError e || isPermissionError e ->
liftIO $ unlessM (doesDirectoryExist dir) $
ioError e
| otherwise -> liftIO $ ioError e