153 lines
4.3 KiB
Haskell
153 lines
4.3 KiB
Haskell
{- git-annex pseudo-backend
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-
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- This backend does not really do any independant data storage,
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- it relies on the file contents in .git/annex/ in this repo,
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- and other accessible repos.
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-
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- This is an abstract backend; getKey has to be implemented to complete
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- it.
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-
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- Copyright 2010 Joey Hess <joey@kitenet.net>
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-
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- Licensed under the GNU GPL version 3 or higher.
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-}
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module Backend.File (backend) where
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import Control.Monad.State
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import System.IO
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import System.Cmd
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import System.Cmd.Utils
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import Control.Exception
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import System.Directory
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import List
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import Maybe
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import TypeInternals
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import LocationLog
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import Locations
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import qualified Remotes
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import qualified GitRepo as Git
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import Utility
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import Core
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import qualified Annex
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import UUID
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import qualified Backend
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backend = Backend {
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name = mustProvide,
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getKey = mustProvide,
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storeFileKey = dummyStore,
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retrieveKeyFile = copyKeyFile,
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removeKey = checkRemoveKey,
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hasKey = checkKeyFile
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}
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mustProvide = error "must provide this field"
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{- Storing a key is a no-op. -}
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dummyStore :: FilePath -> Key -> Annex (Bool)
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dummyStore file key = return True
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{- Just check if the .git/annex/ file for the key exists. -}
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checkKeyFile :: Key -> Annex Bool
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checkKeyFile k = inAnnex k
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{- Try to find a copy of the file in one of the remotes,
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- and copy it over to this one. -}
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copyKeyFile :: Key -> FilePath -> Annex (Bool)
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copyKeyFile key file = do
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remotes <- Remotes.keyPossibilities key
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if (null remotes)
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then do
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showNote "not available"
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showLocations key
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return False
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else trycopy remotes remotes
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where
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trycopy full [] = do
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showNote "not available"
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showTriedRemotes full
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showLocations key
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return False
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trycopy full (r:rs) = do
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probablythere <- probablyPresent r
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if (probablythere)
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then do
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showNote $ "copying from " ++ (Git.repoDescribe r) ++ "..."
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copied <- Remotes.copyFromRemote r key file
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if (copied)
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then return True
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else trycopy full rs
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else trycopy full rs
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probablyPresent r = do
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-- This check is to avoid an ugly message if a
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-- remote is a drive that is not mounted.
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-- Avoid checking inAnnex for ssh remotes because
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-- that is unnecessarily slow, and the locationlog
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-- should be trusted. (If the ssh remote is down
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-- or really lacks the file, it's ok to show
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-- an ugly message before going on to the next
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-- remote.)
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if (not $ Git.repoIsUrl r)
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then liftIO $ doesFileExist $ annexLocation r key
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else return True
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{- Checks remotes to verify that enough copies of a key exist to allow
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- for a key to be safely removed (with no data loss), and fails with an
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- error if not. -}
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checkRemoveKey :: Key -> Annex (Bool)
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checkRemoveKey key = do
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force <- Annex.flagIsSet "force"
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if (force)
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then return True
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else do
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g <- Annex.gitRepo
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remotes <- Remotes.keyPossibilities key
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let numcopies = read $ Git.configGet g config "1"
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if (numcopies > length remotes)
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then notEnoughCopies numcopies (length remotes) []
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else findcopies numcopies 0 remotes []
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where
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config = "annex.numcopies"
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findcopies need have [] bad =
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if (have >= need)
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then return True
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else notEnoughCopies need have bad
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findcopies need have (r:rs) bad = do
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if (have >= need)
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then return True
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else do
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haskey <- Remotes.inAnnex r key
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case (haskey) of
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Right True -> findcopies need (have+1) rs bad
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Right False -> findcopies need have rs bad
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Left _ -> findcopies need have rs (r:bad)
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notEnoughCopies need have bad = do
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unsafe
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showLongNote $
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"Could only verify the existence of " ++
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(show have) ++ " out of " ++ (show need) ++
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" necessary copies"
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showTriedRemotes bad
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showLocations key
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hint
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return False
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unsafe = showNote "unsafe"
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hint = showLongNote $ "(Use --force to override this check, or adjust annex.numcopies.)"
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showLocations :: Key -> Annex ()
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showLocations key = do
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g <- Annex.gitRepo
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u <- getUUID g
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uuids <- liftIO $ keyLocations g key
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let uuidsf = filter (\v -> v /= u) uuids
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ppuuids <- prettyPrintUUIDs uuidsf
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if (null uuidsf)
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then showLongNote $ "No other repository is known to contain the file."
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else showLongNote $ "Try making some of these repositories available:\n" ++ ppuuids
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showTriedRemotes [] = return ()
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showTriedRemotes remotes =
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showLongNote $ "I was unable to access these remotes: " ++
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(Remotes.list remotes)
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