git-annex/Annex/Difference.hs
Joey Hess ba3825441c rework Differences data type
Eliminated complexity and future proofed. The most important change is that
all functions over Difference are now total; any Difference that can be
expressed should be handled. Avoids needs for sanity checking of inputs,
and version skew with the future.

Also, the difference.log now serializes a [Difference], not a Differences.
This saves space and keeps it simpler.

Note that [Difference] might contain conflicting differences (eg,
[Version5, Version6]. In this case, one of them needs to consistently win
over the others, probably based on Ord.
2015-01-28 13:50:02 -04:00

58 lines
1.7 KiB
Haskell

{- git-annex repository differences
-
- Copyright 2015 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Annex.Difference (
module Types.Difference,
setDifferences,
) where
import Common.Annex
import Types.Difference
import Logs.Difference
import Config
import Annex.UUID
import Logs.UUID
import Annex.Version
import qualified Annex
import qualified Data.Map as M
-- Differences are only allowed to be tweaked when initializing a
-- repository for the first time, and then only if there is not another
-- known uuid. If the repository was cloned from elsewhere, it inherits
-- the existing settings.
--
-- Must be called before setVersion, so it can check if this is the first
-- time the repository is being initialized.
setDifferences :: Annex ()
setDifferences = do
u <- getUUID
otherds <- allDifferences <$> recordedDifferences
ds <- mappend otherds . annexDifferences <$> Annex.getGitConfig
when (ds /= mempty) $ do
ds'@(Differences l) <- ifM (isJust <$> getVersion)
( do
oldds <- recordedDifferencesFor u
when (ds /= oldds) $
warning $ "Cannot change tunable parameters in already initialized repository."
return oldds
, if otherds == mempty
then ifM (not . null . filter (/= u) . M.keys <$> uuidMap)
( do
warning "Cannot change tunable parameters in a clone of an existing repository."
return mempty
, return ds
)
else if otherds /= ds
then do
warning "The specified tunable parameters differ from values being used in other clones of this repository."
return otherds
else return ds
)
forM_ l $ \d ->
setConfig (ConfigKey $ differenceConfigKey d) (differenceConfigVal d)
recordDifferences ds' u