git-annex/Annex/Drop.hs

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{- dropping of unwanted content
-
- Copyright 2012-2014 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
module Annex.Drop where
import Annex.Common
import qualified Annex
import Logs.Trust
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import Annex.NumCopies
import Types.Remote (uuid, appendonly, config)
import qualified Remote
import qualified Command.Drop
import Command
import Annex.Wanted
import Annex.Content
import Annex.SpecialRemote.Config
import qualified Database.Keys
import Git.FilePath
import qualified Data.Set as S
import System.Log.Logger (debugM)
type Reason = String
{- Drop a key from local and/or remote when allowed by the preferred content
- and numcopies settings.
-
- Skips trying to drop from remotes that are appendonly, since those drops
- would presumably fail. Also skips dropping from exporttree remotes,
- which don't allow dropping individual keys.
-
- The UUIDs are ones where the content is believed to be present.
- The Remote list can include other remotes that do not have the content;
- only ones that match the UUIDs will be dropped from.
-
- If allowed to drop fromhere, that drop will be done last. This is done
- because local drops do not need any LockedCopy evidence, and so dropping
- from local last allows the content to be removed from more remotes.
-
- A VerifiedCopy can be provided as an optimisation when eg, a key
- has just been uploaded to a remote.
-
- The runner is used to run CommandStart sequentially, it's typically
- callCommandAction.
-}
handleDropsFrom :: [UUID] -> [Remote] -> Reason -> Bool -> Key -> AssociatedFile -> SeekInput -> [VerifiedCopy] -> (CommandStart -> CommandCleanup) -> Annex ()
handleDropsFrom locs rs reason fromhere key afile si preverified runner = do
g <- Annex.gitRepo
l <- map (`fromTopFilePath` g)
<$> Database.Keys.getAssociatedFiles key
let fs = case afile of
AssociatedFile (Just f) -> nub (f : l)
AssociatedFile Nothing -> l
n <- getcopies fs
void $ if fromhere && checkcopies n Nothing
then go fs rs n >>= dropl fs
else go fs rs n
where
getcopies fs = do
(untrusted, have) <- trustPartition UnTrusted locs
numcopies <- if null fs
then getNumCopies
else maximum <$> mapM (getFileNumCopies . fromRawFilePath) fs
return (NumCopies (length have), numcopies, S.fromList untrusted)
{- Check that we have enough copies still to drop the content.
- When the remote being dropped from is untrusted, it was not
- counted as a copy, so having only numcopies suffices. Otherwise,
- we need more than numcopies to safely drop. -}
checkcopies (have, numcopies, _untrusted) Nothing = have > numcopies
checkcopies (have, numcopies, untrusted) (Just u)
| S.member u untrusted = have >= numcopies
| otherwise = have > numcopies
decrcopies (have, numcopies, untrusted) Nothing =
(NumCopies (fromNumCopies have - 1), numcopies, untrusted)
decrcopies v@(_have, _numcopies, untrusted) (Just u)
| S.member u untrusted = v
| otherwise = decrcopies v Nothing
go _ [] n = pure n
go fs (r:rest) n
| uuid r `S.notMember` slocs = go fs rest n
| appendonly r = go fs rest n
| exportTree (config r) = go fs rest n
| checkcopies n (Just $ Remote.uuid r) =
dropr fs r n >>= go fs rest
| otherwise = pure n
checkdrop fs n u a
| null fs = check $ -- no associated files; unused content
wantDrop True u (Just key) (AssociatedFile Nothing)
| otherwise = check $
allM (wantDrop True u (Just key) . AssociatedFile . Just) fs
where
check c = ifM c
( dodrop n u a
, return n
)
dodrop n@(have, numcopies, _untrusted) u a =
ifM (safely $ runner $ a numcopies)
( do
liftIO $ debugM "drop" $ unwords
[ "dropped"
, case afile of
AssociatedFile Nothing -> serializeKey key
AssociatedFile (Just af) -> fromRawFilePath af
, "(from " ++ maybe "here" show u ++ ")"
, "(copies now " ++ show (fromNumCopies have - 1) ++ ")"
, ": " ++ reason
]
return $ decrcopies n u
, return n
)
dropl fs n = checkdrop fs n Nothing $ \numcopies ->
stopUnless (inAnnex key) $
Command.Drop.startLocal afile ai si numcopies key preverified
dropr fs r n = checkdrop fs n (Just $ Remote.uuid r) $ \numcopies ->
Command.Drop.startRemote afile ai si numcopies key r
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ai = mkActionItem (key, afile)
slocs = S.fromList locs
safely a = either (const False) id <$> tryNonAsync a