git-annex/Annex/Content/LowLevel.hs
2018-08-22 14:45:53 -04:00

134 lines
4.7 KiB
Haskell

{- git-annex low-level content functions
-
- Copyright 2010-2018 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU GPL version 3 or higher.
-}
{-# LANGUAGE CPP #-}
module Annex.Content.LowLevel where
import System.PosixCompat.Files
import Annex.Common
import Logs.Transfer
import qualified Annex
import Utility.DiskFree
import Utility.FileMode
import Utility.DataUnits
import Utility.CopyFile
{- Runs the secure erase command if set, otherwise does nothing.
- File may or may not be deleted at the end; caller is responsible for
- making sure it's deleted. -}
secureErase :: FilePath -> Annex ()
secureErase file = maybe noop go =<< annexSecureEraseCommand <$> Annex.getGitConfig
where
go basecmd = void $ liftIO $
boolSystem "sh" [Param "-c", Param $ gencmd basecmd]
gencmd = massReplace [ ("%file", shellEscape file) ]
{- Hard links or copies src to dest, which must not already exist.
-
- Only uses a hard link when annex.thin is enabled and when src is
- not already hardlinked to elsewhere.
-
- Checks disk reserve before copying against the size of the key,
- and will fail if not enough space, or if the dest file already exists.
-
- The FileMode, if provided, influences the mode of the dest file.
- In particular, if it has an execute bit set, the dest file's
- execute bit will be set. The mode is not fully copied over because
- git doesn't support file modes beyond execute.
-}
linkOrCopy :: Key -> FilePath -> FilePath -> Maybe FileMode -> Annex Bool
linkOrCopy = linkOrCopy' (annexThin <$> Annex.getGitConfig)
linkOrCopy' :: Annex Bool -> Key -> FilePath -> FilePath -> Maybe FileMode -> Annex Bool
linkOrCopy' canhardlink key src dest destmode
| maybe False isExecutable destmode = copy =<< getstat
| otherwise = catchBoolIO $
ifM canhardlink
( hardlink
, copy =<< getstat
)
where
hardlink = do
s <- getstat
if linkCount s > 1
then copy s
else liftIO (createLink src dest >> preserveGitMode dest destmode >> return True)
`catchIO` const (copy s)
copy = checkedCopyFile' key src dest destmode
getstat = liftIO $ getFileStatus src
{- Checks disk space before copying. -}
checkedCopyFile :: Key -> FilePath -> FilePath -> Maybe FileMode -> Annex Bool
checkedCopyFile key src dest destmode = catchBoolIO $
checkedCopyFile' key src dest destmode
=<< liftIO (getFileStatus src)
checkedCopyFile' :: Key -> FilePath -> FilePath -> Maybe FileMode -> FileStatus -> Annex Bool
checkedCopyFile' key src dest destmode s = catchBoolIO $
ifM (checkDiskSpace' (fromIntegral $ fileSize s) (Just $ takeDirectory dest) key 0 True)
( liftIO $
copyFileExternal CopyAllMetaData src dest
<&&> preserveGitMode dest destmode
, return False
)
preserveGitMode :: FilePath -> Maybe FileMode -> IO Bool
preserveGitMode f (Just mode)
| isExecutable mode = catchBoolIO $ do
modifyFileMode f $ addModes executeModes
return True
| otherwise = catchBoolIO $ do
modifyFileMode f $ removeModes executeModes
return True
preserveGitMode _ _ = return True
{- Checks that there is disk space available to store a given key,
- in a destination directory (or the annex) printing a warning if not.
-
- If the destination is on the same filesystem as the annex,
- checks for any other running downloads, removing the amount of data still
- to be downloaded from the free space. This way, we avoid overcommitting
- when doing concurrent downloads.
-}
checkDiskSpace :: Maybe FilePath -> Key -> Integer -> Bool -> Annex Bool
checkDiskSpace destdir key = checkDiskSpace' (fromMaybe 1 (keySize key)) destdir key
{- Allows specifying the size of the key, if it's known, which is useful
- as not all keys know their size. -}
checkDiskSpace' :: Integer -> Maybe FilePath -> Key -> Integer -> Bool -> Annex Bool
checkDiskSpace' need destdir key alreadythere samefilesystem = ifM (Annex.getState Annex.force)
( return True
, do
-- We can't get inprogress and free at the same
-- time, and both can be changing, so there's a
-- small race here. Err on the side of caution
-- by getting inprogress first, so if it takes
-- a while, we'll see any decrease in the free
-- disk space.
inprogress <- if samefilesystem
then sizeOfDownloadsInProgress (/= key)
else pure 0
dir >>= liftIO . getDiskFree >>= \case
Just have -> do
reserve <- annexDiskReserve <$> Annex.getGitConfig
let delta = need + reserve - have - alreadythere + inprogress
let ok = delta <= 0
unless ok $
warning $ needMoreDiskSpace delta
return ok
_ -> return True
)
where
dir = maybe (fromRepo gitAnnexDir) return destdir
needMoreDiskSpace :: Integer -> String
needMoreDiskSpace n = "not enough free space, need " ++
roughSize storageUnits True n ++ " more" ++ forcemsg
where
forcemsg = " (use --force to override this check or adjust annex.diskreserve)"