git-annex/Types/Difference.hs
Joey Hess 4e11cb19ef
implemented cloneSimRepo
Started on updateSimRepoState
2024-09-06 14:23:29 -04:00

145 lines
4.5 KiB
Haskell

{- git-annex repository differences
-
- Copyright 2015-2024 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,
mkDifferences,
) 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 standard repository format.
--
-- The serialization is stored in difference.log, so avoid changes that
-- would break compatibility.
--
-- Not breaking compatibility 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
| Simulation
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
, simulation :: 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
, simulation
]
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
, simulation = simulation a || simulation b
}
appendDifferences _ _ = UnknownDifferences
instance Sem.Semigroup Differences where
(<>) = appendDifferences
instance Monoid Differences where
mempty = Differences False 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' =<< flip Git.Config.getMaybe r =<< differenceConfigKey d of
Just True -> Just d
_ -> Nothing
differenceConfigKey :: Difference -> Maybe ConfigKey
differenceConfigKey ObjectHashLower = tunable "objecthashlower"
differenceConfigKey OneLevelObjectHash = tunable "objecthash1"
differenceConfigKey OneLevelBranchHash = tunable "branchhash1"
differenceConfigKey Simulation = Nothing
differenceConfigVal :: Difference -> String
differenceConfigVal _ = Git.Config.boolConfig True
tunable :: B.ByteString -> Maybe ConfigKey
tunable k = Just $ 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
hasDifference Simulation ds = simulation ds
listDifferences :: Differences -> [Difference]
listDifferences d@(Differences {}) = map snd $
filter (\(f, _) -> f d)
[ (objectHashLower, ObjectHashLower)
, (oneLevelObjectHash, OneLevelObjectHash)
, (oneLevelBranchHash, OneLevelBranchHash)
, (simulation, Simulation)
]
listDifferences UnknownDifferences = []
mkDifferences :: S.Set Difference -> Differences
mkDifferences s = Differences
{ objectHashLower = check ObjectHashLower
, oneLevelObjectHash = check OneLevelObjectHash
, oneLevelBranchHash = check OneLevelBranchHash
, simulation = check Simulation
}
where
check f = f `S.member` s