git-annex/Limit.hs
Joey Hess bc649a35ba added preferred-content log, and allow editing it with vicfg
This includes a full parser for the boolean expressions in the log,
that compiles them into Matchers. Those matchers are not used yet.

A complication is that matching against an expression should never
crash git-annex with an error. Instead, vicfg checks that the expressions
parse. If a bad expression (or an expression understood by some future
git-annex version) gets into the log, it'll be ignored.

Most of the code in Limit couldn't fail anyway, but I did have to make
limitCopies check its parameter first, and return an error if it's bad,
rather than erroring at runtime.
2012-10-04 16:00:19 -04:00

144 lines
4.3 KiB
Haskell

{- user-specified limits on files to act on
-
- Copyright 2011,2012 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Limit where
import Text.Regex.PCRE.Light.Char8
import System.Path.WildMatch
import Data.Time.Clock.POSIX
import qualified Data.Set as S
import Common.Annex
import qualified Annex
import qualified Utility.Matcher
import qualified Remote
import qualified Backend
import Annex.Content
import Logs.Trust
import Types.TrustLevel
import Logs.Group
import Utility.HumanTime
type Limit = Utility.Matcher.Token (FilePath -> Annex Bool)
type MkLimit = String -> Either String (FilePath -> Annex Bool)
{- Checks if there are user-specified limits. -}
limited :: Annex Bool
limited = (not . Utility.Matcher.matchesAny) <$> getMatcher'
{- Gets a matcher for the user-specified limits. The matcher is cached for
- speed; once it's obtained the user-specified limits can't change. -}
getMatcher :: Annex (FilePath -> Annex Bool)
getMatcher = Utility.Matcher.matchM <$> getMatcher'
getMatcher' :: Annex (Utility.Matcher.Matcher (FilePath -> Annex Bool))
getMatcher' = do
m <- Annex.getState Annex.limit
case m of
Right r -> return r
Left l -> do
let matcher = Utility.Matcher.generate (reverse l)
Annex.changeState $ \s -> s { Annex.limit = Right matcher }
return matcher
{- Adds something to the limit list, which is built up reversed. -}
add :: Limit -> Annex ()
add l = Annex.changeState $ \s -> s { Annex.limit = prepend $ Annex.limit s }
where
prepend (Left ls) = Left $ l:ls
prepend _ = error "internal"
{- Adds a new token. -}
addToken :: String -> Annex ()
addToken = add . Utility.Matcher.token
{- Adds a new limit. -}
addLimit :: Either String (FilePath -> Annex Bool) -> Annex ()
addLimit = either error (add . Utility.Matcher.Operation)
{- Add a limit to skip files that do not match the glob. -}
addInclude :: String -> Annex ()
addInclude = addLimit . limitInclude
limitInclude :: MkLimit
limitInclude glob = Right $ return . matchglob glob
{- Add a limit to skip files that match the glob. -}
addExclude :: String -> Annex ()
addExclude = addLimit . limitExclude
limitExclude :: MkLimit
limitExclude glob = Right $ return . not . matchglob glob
matchglob :: String -> FilePath -> Bool
matchglob glob f = isJust $ match cregex f []
where
cregex = compile regex []
regex = '^':wildToRegex glob
{- Adds a limit to skip files not believed to be present
- in a specfied repository. -}
addIn :: String -> Annex ()
addIn = addLimit . limitIn
limitIn :: MkLimit
limitIn name = Right $ check $ if name == "." then inAnnex else inremote
where
check a = Backend.lookupFile >=> handle a
handle _ Nothing = return False
handle a (Just (key, _)) = a key
inremote key = do
u <- Remote.nameToUUID name
us <- Remote.keyLocations key
return $ u `elem` us
{- Adds a limit to skip files not believed to have the specified number
- of copies. -}
addCopies :: String -> Annex ()
addCopies = addLimit . limitCopies
limitCopies :: MkLimit
limitCopies want = case split ":" want of
[v, n] -> case readTrustLevel v of
Just trust -> go n $ checktrust trust
Nothing -> go n $ checkgroup v
[n] -> go n $ const $ return True
_ -> Left "bad value for copies"
where
go num good = case readish num of
Nothing -> Left "bad number for copies"
Just n -> Right $ check n good
check n good = Backend.lookupFile >=> handle n good
handle _ _ Nothing = return False
handle n good (Just (key, _)) = do
us <- filterM good =<< Remote.keyLocations key
return $ length us >= n
checktrust t u = (== t) <$> lookupTrust u
checkgroup g u = S.member g <$> lookupGroups u
{- Adds a limit to skip files not using a specified key-value backend. -}
addInBackend :: String -> Annex ()
addInBackend = addLimit . limitInBackend
limitInBackend :: MkLimit
limitInBackend name = Right $ Backend.lookupFile >=> check
where
wanted = Backend.lookupBackendName name
check = return . maybe False ((==) wanted . snd)
addTimeLimit :: String -> Annex ()
addTimeLimit s = do
let seconds = fromMaybe (error "bad time-limit") $ parseDuration s
start <- liftIO getPOSIXTime
let cutoff = start + seconds
addLimit $ Right $ const $ do
now <- liftIO getPOSIXTime
if now > cutoff
then do
warning $ "Time limit (" ++ s ++ ") reached!"
liftIO $ exitWith $ ExitFailure 101
else return True