git-annex/Types/Difference.hs
Joey Hess 37467a008f
annex.addunlocked expressions
* annex.addunlocked can be set to an expression with the same format used by
  annex.largefiles, in case you want to default to unlocking some files but
  not others.
* annex.addunlocked can be configured by git-annex config.

Added a git-annex-matching-expression man page, broken out from
tips/largefiles.

A tricky consequence of this is that git-annex add --relaxed
honors annex.addunlocked, but an expression might want to know the size
or content of an url, which it's not going to download. I decided it was
better not to fail, and just dummy up some plausible data in that case.

Performance impact should be negligible. The global config is already
loaded for annex.largefiles. The expression only has to be parsed once,
and in the simple true/false case, it should not do any additional work
matching it.
2019-12-20 15:56:25 -04:00

136 lines
4.2 KiB
Haskell

{- git-annex repository differences
-
- Copyright 2015 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
{-# LANGUAGE OverloadedStrings #-}
module Types.Difference (
Difference(..),
Differences(..),
readDifferences,
showDifferences,
getDifferences,
differenceConfigKey,
differenceConfigVal,
hasDifference,
listDifferences,
) where
import Utility.PartialPrelude
import qualified Git
import qualified Git.Config
import Git.Types
import Data.Maybe
import Data.Monoid
import qualified Data.ByteString as B
import qualified Data.Set as S
import qualified Data.Semigroup as Sem
import Prelude
-- Describes differences from the v5 repository format.
--
-- The serialization is stored in difference.log, so avoid changes that
-- would break compatability.
--
-- Not breaking compatability is why a list of Differences is used, rather
-- than a record type. With a record type, adding a new field for some future
-- difference would serialize to a value that an older version could not
-- parse, even if that new field was not used. With the Differences list,
-- old versions can still parse it, unless the new Difference constructor
-- is used.
--
-- The constructors intentionally do not have parameters; this is to
-- ensure that any Difference that can be expressed is supported.
-- So, a new repository version would be Version6, rather than Version Int.
data Difference
= ObjectHashLower
| OneLevelObjectHash
| OneLevelBranchHash
deriving (Show, Read, Eq, Ord, Enum, Bounded)
-- This type is used internally for efficient checking for differences,
-- but converted to S.Set Difference for serialization.
data Differences
= Differences
{ objectHashLower :: Bool
, oneLevelObjectHash :: Bool
, oneLevelBranchHash :: Bool
}
| UnknownDifferences
-- UnknownDifferences cannot be equal
instance Eq Differences where
UnknownDifferences == _ = False
_ == UnknownDifferences = False
a == b = all (\f -> f a == f b)
[ objectHashLower
, oneLevelObjectHash
, oneLevelBranchHash
]
appendDifferences :: Differences -> Differences -> Differences
appendDifferences a@(Differences {}) b@(Differences {}) = a
{ objectHashLower = objectHashLower a || objectHashLower b
, oneLevelObjectHash = oneLevelObjectHash a || oneLevelObjectHash b
, oneLevelBranchHash = oneLevelBranchHash a || oneLevelBranchHash b
}
appendDifferences _ _ = UnknownDifferences
instance Sem.Semigroup Differences where
(<>) = appendDifferences
instance Monoid Differences where
mempty = Differences False False False
readDifferences :: String -> Differences
readDifferences = maybe UnknownDifferences mkDifferences . readish
showDifferences :: Differences -> String
showDifferences = show . S.fromList . listDifferences
getDifferences :: Git.Repo -> Differences
getDifferences r = mkDifferences $ S.fromList $
mapMaybe getmaybe [minBound .. maxBound]
where
getmaybe d = case Git.Config.isTrueFalse' =<< Git.Config.getMaybe (differenceConfigKey d) r of
Just True -> Just d
_ -> Nothing
differenceConfigKey :: Difference -> ConfigKey
differenceConfigKey ObjectHashLower = tunable "objecthashlower"
differenceConfigKey OneLevelObjectHash = tunable "objecthash1"
differenceConfigKey OneLevelBranchHash = tunable "branchhash1"
differenceConfigVal :: Difference -> String
differenceConfigVal _ = Git.Config.boolConfig True
tunable :: B.ByteString -> ConfigKey
tunable k = ConfigKey ("annex.tune." <> k)
hasDifference :: Difference -> Differences -> Bool
hasDifference _ UnknownDifferences = False
hasDifference ObjectHashLower ds = objectHashLower ds
hasDifference OneLevelObjectHash ds = oneLevelObjectHash ds
hasDifference OneLevelBranchHash ds = oneLevelBranchHash ds
listDifferences :: Differences -> [Difference]
listDifferences d@(Differences {}) = map snd $
filter (\(f, _) -> f d)
[ (objectHashLower, ObjectHashLower)
, (oneLevelObjectHash, OneLevelObjectHash)
, (oneLevelBranchHash, OneLevelBranchHash)
]
listDifferences UnknownDifferences = []
mkDifferences :: S.Set Difference -> Differences
mkDifferences s = Differences
{ objectHashLower = check ObjectHashLower
, oneLevelObjectHash = check OneLevelObjectHash
, oneLevelBranchHash = check OneLevelBranchHash
}
where
check f = f `S.member` s