git-annex/Remote/Directory.hs

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{- A "remote" that is just a filesystem directory.
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-
- Copyright 2011-2020 Joey Hess <id@joeyh.name>
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-
- Licensed under the GNU AGPL version 3 or higher.
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-}
{-# LANGUAGE CPP #-}
module Remote.Directory (
remote,
finalizeStoreGeneric,
removeDirGeneric,
) where
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import qualified Data.ByteString.Lazy as L
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import qualified Data.Map as M
import Data.Default
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import Annex.Common
import Types.Remote
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import Types.Export
import Types.Creds
import qualified Git
import Config.Cost
import Config
import Annex.SpecialRemote.Config
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import Utility.FileMode
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import Remote.Helper.Special
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import Remote.Helper.ExportImport
import Types.Import
import qualified Remote.Directory.LegacyChunked as Legacy
import Annex.Content
import Annex.UUID
import Utility.Metered
import Utility.Tmp
import Utility.InodeCache
import Types.ProposedAccepted
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remote :: RemoteType
remote = specialRemoteType $ RemoteType
{ typename = "directory"
, enumerate = const (findSpecialRemotes "directory")
, generate = gen
, configParser = [optionalStringParser directoryField]
, setup = directorySetup
, exportSupported = exportIsSupported
, importSupported = importIsSupported
}
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directoryField :: RemoteConfigField
directoryField = Accepted "directory"
gen :: Git.Repo -> UUID -> ParsedRemoteConfig -> RemoteGitConfig -> RemoteStateHandle -> Annex (Maybe Remote)
gen r u c gc rs = do
cst <- remoteCost gc cheapRemoteCost
let chunkconfig = getChunkConfig c
return $ Just $ specialRemote c
(prepareStore dir chunkconfig)
(retrieveKeyFileM dir chunkconfig)
(simplyPrepare $ removeKeyM dir)
(simplyPrepare $ checkPresentM dir chunkconfig)
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Remote
{ uuid = u
, cost = cst
, name = Git.repoDescribe r
, storeKey = storeKeyDummy
, retrieveKeyFile = retreiveKeyFileDummy
, retrieveKeyFileCheap = retrieveKeyFileCheapM dir chunkconfig
, retrievalSecurityPolicy = RetrievalAllKeysSecure
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, removeKey = removeKeyDummy
, lockContent = Nothing
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, checkPresent = checkPresentDummy
, checkPresentCheap = True
, exportActions = ExportActions
{ storeExport = storeExportM dir
, retrieveExport = retrieveExportM dir
, removeExport = removeExportM dir
, checkPresentExport = checkPresentExportM dir
-- Not needed because removeExportLocation
-- auto-removes empty directories.
, removeExportDirectory = Nothing
, renameExport = renameExportM dir
}
, importActions = ImportActions
{ listImportableContents = listImportableContentsM dir
, retrieveExportWithContentIdentifier = retrieveExportWithContentIdentifierM dir
, storeExportWithContentIdentifier = storeExportWithContentIdentifierM dir
, removeExportWithContentIdentifier = removeExportWithContentIdentifierM dir
-- Not needed because removeExportWithContentIdentifier
-- auto-removes empty directories.
, removeExportDirectoryWhenEmpty = Nothing
, checkPresentExportWithContentIdentifier = checkPresentExportWithContentIdentifierM dir
}
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, whereisKey = Nothing
, remoteFsck = Nothing
, repairRepo = Nothing
, config = c
, getRepo = return r
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, gitconfig = gc
, localpath = Just dir
, readonly = False
, appendonly = False
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, availability = LocallyAvailable
, remotetype = remote
, mkUnavailable = gen r u c
(gc { remoteAnnexDirectory = Just "/dev/null" }) rs
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, getInfo = return [("directory", dir)]
, claimUrl = Nothing
, checkUrl = Nothing
, remoteStateHandle = rs
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}
where
dir = fromMaybe (giveup "missing directory") $ remoteAnnexDirectory gc
directorySetup :: SetupStage -> Maybe UUID -> Maybe CredPair -> RemoteConfig -> RemoteGitConfig -> Annex (RemoteConfig, UUID)
directorySetup _ mu _ c gc = do
u <- maybe (liftIO genUUID) return mu
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-- verify configuration is sane
let dir = maybe (giveup "Specify directory=") fromProposedAccepted $
M.lookup directoryField c
absdir <- liftIO $ absPath dir
liftIO $ unlessM (doesDirectoryExist absdir) $
giveup $ "Directory does not exist: " ++ absdir
(c', _encsetup) <- encryptionSetup c gc
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-- The directory is stored in git config, not in this remote's
-- persistant state, so it can vary between hosts.
gitConfigSpecialRemote u c' [("directory", absdir)]
return (M.delete directoryField c', u)
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{- Locations to try to access a given Key in the directory.
- We try more than one since we used to write to different hash
- directories. -}
locations :: FilePath -> Key -> [FilePath]
locations d k = map (\f -> d </> fromRawFilePath f) (keyPaths k)
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{- Returns the location off a Key in the directory. If the key is
- present, returns the location that is actually used, otherwise
- returns the first, default location. -}
getLocation :: FilePath -> Key -> IO FilePath
getLocation d k = do
let locs = locations d k
fromMaybe (Prelude.head locs) <$> firstM doesFileExist locs
{- Directory where the file(s) for a key are stored. -}
storeDir :: FilePath -> Key -> FilePath
storeDir d k = addTrailingPathSeparator $
d </> fromRawFilePath (hashDirLower def k) </> fromRawFilePath (keyFile k)
{- Check if there is enough free disk space in the remote's directory to
- store the key. Note that the unencrypted key size is checked. -}
prepareStore :: FilePath -> ChunkConfig -> Preparer Storer
add API for exporting Implemented so far for the directory special remote. Several remotes don't make sense to export to. Regular Git remotes, obviously, do not. Bup remotes almost certianly do not, since bup would need to be used to extract the export; same store for Ddar. Web and Bittorrent are download-only. GCrypt is always encrypted so exporting to it would be pointless. There's probably no point complicating the Hook remotes with exporting at this point. External, S3, Glacier, WebDAV, Rsync, and possibly Tahoe should be modified to support export. Thought about trying to reuse the storeKey/retrieveKeyFile/removeKey interface, rather than adding a new interface. But, it seemed better to keep it separate, to avoid a complicated interface that sometimes encrypts/chunks key/value storage and sometimes users non-key/value storage. Any common parts can be factored out. Note that storeExport is not atomic. doc/design/exporting_trees_to_special_remotes.mdwn has some things in the "resuming exports" section that bear on this decision. Basically, I don't think, at this time, that an atomic storeExport would help with resuming, because exports are not key/value storage, and we can't be sure that a partially uploaded file is the same content we're currently trying to export. Also, note that ExportLocation will always use unix path separators. This is important, because users may export from a mix of windows and unix, and it avoids complicating the API with path conversions, and ensures that in such a mix, they always use the same locations for exports. This commit was sponsored by Bruno BEAUFILS on Patreon.
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prepareStore d chunkconfig = checkPrepare (checkDiskSpaceDirectory d)
(byteStorer $ store d chunkconfig)
where
add API for exporting Implemented so far for the directory special remote. Several remotes don't make sense to export to. Regular Git remotes, obviously, do not. Bup remotes almost certianly do not, since bup would need to be used to extract the export; same store for Ddar. Web and Bittorrent are download-only. GCrypt is always encrypted so exporting to it would be pointless. There's probably no point complicating the Hook remotes with exporting at this point. External, S3, Glacier, WebDAV, Rsync, and possibly Tahoe should be modified to support export. Thought about trying to reuse the storeKey/retrieveKeyFile/removeKey interface, rather than adding a new interface. But, it seemed better to keep it separate, to avoid a complicated interface that sometimes encrypts/chunks key/value storage and sometimes users non-key/value storage. Any common parts can be factored out. Note that storeExport is not atomic. doc/design/exporting_trees_to_special_remotes.mdwn has some things in the "resuming exports" section that bear on this decision. Basically, I don't think, at this time, that an atomic storeExport would help with resuming, because exports are not key/value storage, and we can't be sure that a partially uploaded file is the same content we're currently trying to export. Also, note that ExportLocation will always use unix path separators. This is important, because users may export from a mix of windows and unix, and it avoids complicating the API with path conversions, and ensures that in such a mix, they always use the same locations for exports. This commit was sponsored by Bruno BEAUFILS on Patreon.
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checkDiskSpaceDirectory :: FilePath -> Key -> Annex Bool
checkDiskSpaceDirectory d k = do
annexdir <- fromRepo gitAnnexObjectDir
samefilesystem <- liftIO $ catchDefaultIO False $
(\a b -> deviceID a == deviceID b)
<$> getFileStatus d
<*> getFileStatus annexdir
checkDiskSpace (Just d) k 0 samefilesystem
store :: FilePath -> ChunkConfig -> Key -> L.ByteString -> MeterUpdate -> Annex Bool
store d chunkconfig k b p = liftIO $ do
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void $ tryIO $ createDirectoryIfMissing True tmpdir
case chunkconfig of
LegacyChunks chunksize -> Legacy.store chunksize finalizeStoreGeneric k b p tmpdir destdir
_ -> do
let tmpf = tmpdir </> kf
meteredWriteFile p tmpf b
finalizeStoreGeneric tmpdir destdir
return True
where
tmpdir = addTrailingPathSeparator $ d </> "tmp" </> kf
kf = fromRawFilePath (keyFile k)
destdir = storeDir d k
{- Passed a temp directory that contains the files that should be placed
- in the dest directory, moves it into place. Anything already existing
- in the dest directory will be deleted. File permissions will be locked
- down. -}
finalizeStoreGeneric :: FilePath -> FilePath -> IO ()
finalizeStoreGeneric tmp dest = do
void $ tryIO $ allowWrite dest -- may already exist
void $ tryIO $ removeDirectoryRecursive dest -- or not exist
createDirectoryIfMissing True (parentDir dest)
renameDirectory tmp dest
-- may fail on some filesystems
void $ tryIO $ do
mapM_ preventWrite =<< dirContents dest
preventWrite dest
retrieveKeyFileM :: FilePath -> ChunkConfig -> Preparer Retriever
retrieveKeyFileM d (LegacyChunks _) = Legacy.retrieve locations d
retrieveKeyFileM d _ = simplyPrepare $ byteRetriever $ \k sink ->
sink =<< liftIO (L.readFile =<< getLocation d k)
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retrieveKeyFileCheapM :: FilePath -> ChunkConfig -> Key -> AssociatedFile -> FilePath -> Annex Bool
-- no cheap retrieval possible for chunks
retrieveKeyFileCheapM _ (UnpaddedChunks _) _ _ _ = return False
retrieveKeyFileCheapM _ (LegacyChunks _) _ _ _ = return False
#ifndef mingw32_HOST_OS
retrieveKeyFileCheapM d NoChunks k _af f = liftIO $ catchBoolIO $ do
file <- absPath =<< getLocation d k
ifM (doesFileExist file)
( do
createSymbolicLink file f
return True
, return False
)
#else
retrieveKeyFileCheapM _ _ _ _ _ = return False
#endif
removeKeyM :: FilePath -> Remover
removeKeyM d k = liftIO $ removeDirGeneric d (storeDir d k)
{- Removes the directory, which must be located under the topdir.
-
- Succeeds even on directories and contents that do not have write
- permission.
-
- If the directory does not exist, succeeds as long as the topdir does
- exist. If the topdir does not exist, fails, because in this case the
- remote is not currently accessible and probably still has the content
- we were supposed to remove from it.
-}
removeDirGeneric :: FilePath -> FilePath -> IO Bool
removeDirGeneric topdir dir = do
void $ tryIO $ allowWrite dir
#ifdef mingw32_HOST_OS
{- Windows needs the files inside the directory to be writable
- before it can delete them. -}
void $ tryIO $ mapM_ allowWrite =<< dirContents dir
#endif
ok <- catchBoolIO $ do
removeDirectoryRecursive dir
return True
if ok
then return ok
else doesDirectoryExist topdir <&&> (not <$> doesDirectoryExist dir)
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checkPresentM :: FilePath -> ChunkConfig -> CheckPresent
checkPresentM d (LegacyChunks _) k = Legacy.checkKey d locations k
checkPresentM d _ k = checkPresentGeneric d (locations d k)
add API for exporting Implemented so far for the directory special remote. Several remotes don't make sense to export to. Regular Git remotes, obviously, do not. Bup remotes almost certianly do not, since bup would need to be used to extract the export; same store for Ddar. Web and Bittorrent are download-only. GCrypt is always encrypted so exporting to it would be pointless. There's probably no point complicating the Hook remotes with exporting at this point. External, S3, Glacier, WebDAV, Rsync, and possibly Tahoe should be modified to support export. Thought about trying to reuse the storeKey/retrieveKeyFile/removeKey interface, rather than adding a new interface. But, it seemed better to keep it separate, to avoid a complicated interface that sometimes encrypts/chunks key/value storage and sometimes users non-key/value storage. Any common parts can be factored out. Note that storeExport is not atomic. doc/design/exporting_trees_to_special_remotes.mdwn has some things in the "resuming exports" section that bear on this decision. Basically, I don't think, at this time, that an atomic storeExport would help with resuming, because exports are not key/value storage, and we can't be sure that a partially uploaded file is the same content we're currently trying to export. Also, note that ExportLocation will always use unix path separators. This is important, because users may export from a mix of windows and unix, and it avoids complicating the API with path conversions, and ensures that in such a mix, they always use the same locations for exports. This commit was sponsored by Bruno BEAUFILS on Patreon.
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checkPresentGeneric :: FilePath -> [FilePath] -> Annex Bool
checkPresentGeneric d ps = checkPresentGeneric' d $
liftIO $ anyM doesFileExist ps
checkPresentGeneric' :: FilePath -> Annex Bool -> Annex Bool
checkPresentGeneric' d check = ifM check
( return True
, ifM (liftIO $ doesDirectoryExist d)
( return False
, giveup $ "directory " ++ d ++ " is not accessible"
)
)
add API for exporting Implemented so far for the directory special remote. Several remotes don't make sense to export to. Regular Git remotes, obviously, do not. Bup remotes almost certianly do not, since bup would need to be used to extract the export; same store for Ddar. Web and Bittorrent are download-only. GCrypt is always encrypted so exporting to it would be pointless. There's probably no point complicating the Hook remotes with exporting at this point. External, S3, Glacier, WebDAV, Rsync, and possibly Tahoe should be modified to support export. Thought about trying to reuse the storeKey/retrieveKeyFile/removeKey interface, rather than adding a new interface. But, it seemed better to keep it separate, to avoid a complicated interface that sometimes encrypts/chunks key/value storage and sometimes users non-key/value storage. Any common parts can be factored out. Note that storeExport is not atomic. doc/design/exporting_trees_to_special_remotes.mdwn has some things in the "resuming exports" section that bear on this decision. Basically, I don't think, at this time, that an atomic storeExport would help with resuming, because exports are not key/value storage, and we can't be sure that a partially uploaded file is the same content we're currently trying to export. Also, note that ExportLocation will always use unix path separators. This is important, because users may export from a mix of windows and unix, and it avoids complicating the API with path conversions, and ensures that in such a mix, they always use the same locations for exports. This commit was sponsored by Bruno BEAUFILS on Patreon.
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storeExportM :: FilePath -> FilePath -> Key -> ExportLocation -> MeterUpdate -> Annex Bool
storeExportM d src _k loc p = liftIO $ catchBoolIO $ do
createDirectoryIfMissing True (takeDirectory dest)
-- Write via temp file so that checkPresentGeneric will not
-- see it until it's fully stored.
viaTmp (\tmp () -> withMeteredFile src p (L.writeFile tmp)) dest ()
return True
add API for exporting Implemented so far for the directory special remote. Several remotes don't make sense to export to. Regular Git remotes, obviously, do not. Bup remotes almost certianly do not, since bup would need to be used to extract the export; same store for Ddar. Web and Bittorrent are download-only. GCrypt is always encrypted so exporting to it would be pointless. There's probably no point complicating the Hook remotes with exporting at this point. External, S3, Glacier, WebDAV, Rsync, and possibly Tahoe should be modified to support export. Thought about trying to reuse the storeKey/retrieveKeyFile/removeKey interface, rather than adding a new interface. But, it seemed better to keep it separate, to avoid a complicated interface that sometimes encrypts/chunks key/value storage and sometimes users non-key/value storage. Any common parts can be factored out. Note that storeExport is not atomic. doc/design/exporting_trees_to_special_remotes.mdwn has some things in the "resuming exports" section that bear on this decision. Basically, I don't think, at this time, that an atomic storeExport would help with resuming, because exports are not key/value storage, and we can't be sure that a partially uploaded file is the same content we're currently trying to export. Also, note that ExportLocation will always use unix path separators. This is important, because users may export from a mix of windows and unix, and it avoids complicating the API with path conversions, and ensures that in such a mix, they always use the same locations for exports. This commit was sponsored by Bruno BEAUFILS on Patreon.
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where
dest = exportPath d loc
retrieveExportM :: FilePath -> Key -> ExportLocation -> FilePath -> MeterUpdate -> Annex Bool
retrieveExportM d _k loc dest p = liftIO $ catchBoolIO $ do
add API for exporting Implemented so far for the directory special remote. Several remotes don't make sense to export to. Regular Git remotes, obviously, do not. Bup remotes almost certianly do not, since bup would need to be used to extract the export; same store for Ddar. Web and Bittorrent are download-only. GCrypt is always encrypted so exporting to it would be pointless. There's probably no point complicating the Hook remotes with exporting at this point. External, S3, Glacier, WebDAV, Rsync, and possibly Tahoe should be modified to support export. Thought about trying to reuse the storeKey/retrieveKeyFile/removeKey interface, rather than adding a new interface. But, it seemed better to keep it separate, to avoid a complicated interface that sometimes encrypts/chunks key/value storage and sometimes users non-key/value storage. Any common parts can be factored out. Note that storeExport is not atomic. doc/design/exporting_trees_to_special_remotes.mdwn has some things in the "resuming exports" section that bear on this decision. Basically, I don't think, at this time, that an atomic storeExport would help with resuming, because exports are not key/value storage, and we can't be sure that a partially uploaded file is the same content we're currently trying to export. Also, note that ExportLocation will always use unix path separators. This is important, because users may export from a mix of windows and unix, and it avoids complicating the API with path conversions, and ensures that in such a mix, they always use the same locations for exports. This commit was sponsored by Bruno BEAUFILS on Patreon.
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withMeteredFile src p (L.writeFile dest)
return True
where
src = exportPath d loc
removeExportM :: FilePath -> Key -> ExportLocation -> Annex Bool
removeExportM d _k loc = liftIO $ do
add API for exporting Implemented so far for the directory special remote. Several remotes don't make sense to export to. Regular Git remotes, obviously, do not. Bup remotes almost certianly do not, since bup would need to be used to extract the export; same store for Ddar. Web and Bittorrent are download-only. GCrypt is always encrypted so exporting to it would be pointless. There's probably no point complicating the Hook remotes with exporting at this point. External, S3, Glacier, WebDAV, Rsync, and possibly Tahoe should be modified to support export. Thought about trying to reuse the storeKey/retrieveKeyFile/removeKey interface, rather than adding a new interface. But, it seemed better to keep it separate, to avoid a complicated interface that sometimes encrypts/chunks key/value storage and sometimes users non-key/value storage. Any common parts can be factored out. Note that storeExport is not atomic. doc/design/exporting_trees_to_special_remotes.mdwn has some things in the "resuming exports" section that bear on this decision. Basically, I don't think, at this time, that an atomic storeExport would help with resuming, because exports are not key/value storage, and we can't be sure that a partially uploaded file is the same content we're currently trying to export. Also, note that ExportLocation will always use unix path separators. This is important, because users may export from a mix of windows and unix, and it avoids complicating the API with path conversions, and ensures that in such a mix, they always use the same locations for exports. This commit was sponsored by Bruno BEAUFILS on Patreon.
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nukeFile src
removeExportLocation d loc
add API for exporting Implemented so far for the directory special remote. Several remotes don't make sense to export to. Regular Git remotes, obviously, do not. Bup remotes almost certianly do not, since bup would need to be used to extract the export; same store for Ddar. Web and Bittorrent are download-only. GCrypt is always encrypted so exporting to it would be pointless. There's probably no point complicating the Hook remotes with exporting at this point. External, S3, Glacier, WebDAV, Rsync, and possibly Tahoe should be modified to support export. Thought about trying to reuse the storeKey/retrieveKeyFile/removeKey interface, rather than adding a new interface. But, it seemed better to keep it separate, to avoid a complicated interface that sometimes encrypts/chunks key/value storage and sometimes users non-key/value storage. Any common parts can be factored out. Note that storeExport is not atomic. doc/design/exporting_trees_to_special_remotes.mdwn has some things in the "resuming exports" section that bear on this decision. Basically, I don't think, at this time, that an atomic storeExport would help with resuming, because exports are not key/value storage, and we can't be sure that a partially uploaded file is the same content we're currently trying to export. Also, note that ExportLocation will always use unix path separators. This is important, because users may export from a mix of windows and unix, and it avoids complicating the API with path conversions, and ensures that in such a mix, they always use the same locations for exports. This commit was sponsored by Bruno BEAUFILS on Patreon.
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return True
where
src = exportPath d loc
checkPresentExportM :: FilePath -> Key -> ExportLocation -> Annex Bool
checkPresentExportM d _k loc =
add API for exporting Implemented so far for the directory special remote. Several remotes don't make sense to export to. Regular Git remotes, obviously, do not. Bup remotes almost certianly do not, since bup would need to be used to extract the export; same store for Ddar. Web and Bittorrent are download-only. GCrypt is always encrypted so exporting to it would be pointless. There's probably no point complicating the Hook remotes with exporting at this point. External, S3, Glacier, WebDAV, Rsync, and possibly Tahoe should be modified to support export. Thought about trying to reuse the storeKey/retrieveKeyFile/removeKey interface, rather than adding a new interface. But, it seemed better to keep it separate, to avoid a complicated interface that sometimes encrypts/chunks key/value storage and sometimes users non-key/value storage. Any common parts can be factored out. Note that storeExport is not atomic. doc/design/exporting_trees_to_special_remotes.mdwn has some things in the "resuming exports" section that bear on this decision. Basically, I don't think, at this time, that an atomic storeExport would help with resuming, because exports are not key/value storage, and we can't be sure that a partially uploaded file is the same content we're currently trying to export. Also, note that ExportLocation will always use unix path separators. This is important, because users may export from a mix of windows and unix, and it avoids complicating the API with path conversions, and ensures that in such a mix, they always use the same locations for exports. This commit was sponsored by Bruno BEAUFILS on Patreon.
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checkPresentGeneric d [exportPath d loc]
renameExportM :: FilePath -> Key -> ExportLocation -> ExportLocation -> Annex (Maybe Bool)
renameExportM d _k oldloc newloc = liftIO $ Just <$> go
add API for exporting Implemented so far for the directory special remote. Several remotes don't make sense to export to. Regular Git remotes, obviously, do not. Bup remotes almost certianly do not, since bup would need to be used to extract the export; same store for Ddar. Web and Bittorrent are download-only. GCrypt is always encrypted so exporting to it would be pointless. There's probably no point complicating the Hook remotes with exporting at this point. External, S3, Glacier, WebDAV, Rsync, and possibly Tahoe should be modified to support export. Thought about trying to reuse the storeKey/retrieveKeyFile/removeKey interface, rather than adding a new interface. But, it seemed better to keep it separate, to avoid a complicated interface that sometimes encrypts/chunks key/value storage and sometimes users non-key/value storage. Any common parts can be factored out. Note that storeExport is not atomic. doc/design/exporting_trees_to_special_remotes.mdwn has some things in the "resuming exports" section that bear on this decision. Basically, I don't think, at this time, that an atomic storeExport would help with resuming, because exports are not key/value storage, and we can't be sure that a partially uploaded file is the same content we're currently trying to export. Also, note that ExportLocation will always use unix path separators. This is important, because users may export from a mix of windows and unix, and it avoids complicating the API with path conversions, and ensures that in such a mix, they always use the same locations for exports. This commit was sponsored by Bruno BEAUFILS on Patreon.
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where
go = catchBoolIO $ do
createDirectoryIfMissing True (takeDirectory dest)
renameFile src dest
removeExportLocation d oldloc
return True
add API for exporting Implemented so far for the directory special remote. Several remotes don't make sense to export to. Regular Git remotes, obviously, do not. Bup remotes almost certianly do not, since bup would need to be used to extract the export; same store for Ddar. Web and Bittorrent are download-only. GCrypt is always encrypted so exporting to it would be pointless. There's probably no point complicating the Hook remotes with exporting at this point. External, S3, Glacier, WebDAV, Rsync, and possibly Tahoe should be modified to support export. Thought about trying to reuse the storeKey/retrieveKeyFile/removeKey interface, rather than adding a new interface. But, it seemed better to keep it separate, to avoid a complicated interface that sometimes encrypts/chunks key/value storage and sometimes users non-key/value storage. Any common parts can be factored out. Note that storeExport is not atomic. doc/design/exporting_trees_to_special_remotes.mdwn has some things in the "resuming exports" section that bear on this decision. Basically, I don't think, at this time, that an atomic storeExport would help with resuming, because exports are not key/value storage, and we can't be sure that a partially uploaded file is the same content we're currently trying to export. Also, note that ExportLocation will always use unix path separators. This is important, because users may export from a mix of windows and unix, and it avoids complicating the API with path conversions, and ensures that in such a mix, they always use the same locations for exports. This commit was sponsored by Bruno BEAUFILS on Patreon.
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src = exportPath d oldloc
dest = exportPath d newloc
exportPath :: FilePath -> ExportLocation -> FilePath
exportPath d loc = d </> fromRawFilePath (fromExportLocation loc)
{- Removes the ExportLocation's parent directory and its parents, so long as
- they're empty, up to but not including the topdir. -}
removeExportLocation :: FilePath -> ExportLocation -> IO ()
removeExportLocation topdir loc =
go (Just $ takeDirectory $ fromRawFilePath $ fromExportLocation loc) (Right ())
where
go _ (Left _e) = return ()
go Nothing _ = return ()
go (Just loc') _ = go (upFrom loc')
=<< tryIO (removeDirectory $ exportPath topdir (mkExportLocation (toRawFilePath loc')))
listImportableContentsM :: FilePath -> Annex (Maybe (ImportableContents (ContentIdentifier, ByteSize)))
listImportableContentsM dir = catchMaybeIO $ liftIO $ do
l <- dirContentsRecursive dir
l' <- mapM go l
return $ ImportableContents (catMaybes l') []
where
go f = do
st <- getFileStatus f
mkContentIdentifier f st >>= \case
Nothing -> return Nothing
Just cid -> do
relf <- toRawFilePath <$> relPathDirToFile dir f
sz <- getFileSize' f st
return $ Just (mkImportLocation relf, (cid, sz))
-- Make a ContentIdentifier that contains an InodeCache.
--
-- The InodeCache is generated without checking a sentinal file.
-- So in a case when a remount etc causes all the inodes to change,
-- files may appear to be modified when they are not, which will only
-- result in extra work to re-import them.
--
-- If the file is not a regular file, this will return Nothing.
mkContentIdentifier :: FilePath -> FileStatus -> IO (Maybe ContentIdentifier)
mkContentIdentifier f st =
fmap (ContentIdentifier . encodeBS . showInodeCache)
<$> toInodeCache noTSDelta f st
retrieveExportWithContentIdentifierM :: FilePath -> ExportLocation -> ContentIdentifier -> FilePath -> Annex (Maybe Key) -> MeterUpdate -> Annex (Maybe Key)
retrieveExportWithContentIdentifierM dir loc cid dest mkkey p =
catchDefaultIO Nothing $ precheck $ docopy postcheck
where
f = exportPath dir loc
docopy cont = do
#ifndef mingw32_HOST_OS
-- Need a duplicate fd for the post check, since
-- hGetContentsMetered closes its handle.
fd <- liftIO $ openFd f ReadOnly Nothing defaultFileFlags
dupfd <- liftIO $ dup fd
h <- liftIO $ fdToHandle fd
#else
h <- liftIO $ openBinaryFile f ReadMode
#endif
liftIO $ hGetContentsMetered h p >>= L.writeFile dest
k <- mkkey
#ifndef mingw32_HOST_OS
cont dupfd (return k)
#else
cont (return k)
#endif
-- Check before copy, to avoid expensive copy of wrong file
-- content.
precheck cont = comparecid cont
=<< liftIO . mkContentIdentifier f
=<< liftIO (getFileStatus f)
-- Check after copy, in case the file was changed while it was
-- being copied.
--
-- When possible (not on Windows), check the same handle
-- that the file was copied from. Avoids some race cases where
-- the file is modified while it's copied but then gets restored
-- to the original content afterwards.
--
-- This does not guard against every possible race, but neither
-- can InodeCaches detect every possible modification to a file.
-- It's probably as good or better than git's handling of similar
-- situations with files being modified while it's updating the
-- working tree for a merge.
#ifndef mingw32_HOST_OS
postcheck fd cont = do
#else
postcheck cont = do
#endif
currcid <- liftIO $ mkContentIdentifier f
#ifndef mingw32_HOST_OS
=<< getFdStatus fd
#else
=<< getFileStatus f
#endif
comparecid cont currcid
comparecid cont currcid
| currcid == Just cid = cont
| otherwise = return Nothing
storeExportWithContentIdentifierM :: FilePath -> FilePath -> Key -> ExportLocation -> [ContentIdentifier] -> MeterUpdate -> Annex (Either String ContentIdentifier)
storeExportWithContentIdentifierM dir src _k loc overwritablecids p =
catchIO go (return . Left . show)
where
go = do
liftIO $ createDirectoryIfMissing True destdir
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withTmpFileIn destdir template $ \tmpf tmph -> do
liftIO $ withMeteredFile src p (L.hPut tmph)
liftIO $ hFlush tmph
liftIO $ hClose tmph
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liftIO (getFileStatus tmpf) >>= liftIO . mkContentIdentifier tmpf >>= \case
Nothing ->
return $ Left "unable to generate content identifier"
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Just newcid ->
checkExportContent dir loc (newcid:overwritablecids) (Left "unsafe to overwrite file") $ const $ do
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liftIO $ rename tmpf dest
return (Right newcid)
dest = exportPath dir loc
(destdir, base) = splitFileName dest
template = relatedTemplate (base ++ ".tmp")
removeExportWithContentIdentifierM :: FilePath -> Key -> ExportLocation -> [ContentIdentifier] -> Annex Bool
removeExportWithContentIdentifierM dir k loc removeablecids =
checkExportContent dir loc removeablecids False $ \case
DoesNotExist -> return True
KnownContentIdentifier -> removeExportM dir k loc
checkPresentExportWithContentIdentifierM :: FilePath -> Key -> ExportLocation -> [ContentIdentifier] -> Annex Bool
checkPresentExportWithContentIdentifierM dir _k loc knowncids =
checkPresentGeneric' dir $
checkExportContent dir loc knowncids False $ \case
DoesNotExist -> return False
KnownContentIdentifier -> return True
data CheckResult = DoesNotExist | KnownContentIdentifier
-- Checks if the content at an ExportLocation is in the knowncids,
-- and only runs the callback that modifies it if it's safe to do so.
--
-- This should avoid races to the extent possible. However,
-- if something has the file open for write, it could write to the handle
-- after the callback has overwritten or deleted it, and its write would
-- be lost, and we don't need to detect that.
-- (In similar situations, git doesn't either!)
--
-- It follows that if something is written to the destination file
-- shortly before, it's acceptable to run the callback anyway, as that's
-- nearly indistinguishable from the above case.
--
-- So, it suffices to check if the destination file's current
-- content is known, and immediately run the callback.
checkExportContent :: FilePath -> ExportLocation -> [ContentIdentifier] -> a -> (CheckResult -> Annex a) -> Annex a
checkExportContent dir loc knowncids unsafe callback =
tryWhenExists (liftIO $ getFileStatus dest) >>= \case
Just destst
| not (isRegularFile destst) -> return unsafe
| otherwise -> catchDefaultIO Nothing (liftIO $ mkContentIdentifier dest destst) >>= \case
Just destcid
| destcid `elem` knowncids -> callback KnownContentIdentifier
-- dest exists with other content
| otherwise -> return unsafe
-- should never happen
Nothing -> return unsafe
-- dest does not exist
Nothing -> callback DoesNotExist
where
dest = exportPath dir loc