Repository tuning parameters can now be passed when initializing a repository for the first time.

* init: Repository tuning parameters can now be passed when initializing a
  repository for the first time. For details, see
  http://git-annex.branchable.com/tuning/
* merge: Refuse to merge changes from a git-annex branch of a repo
  that has been tuned in incompatable ways.

2 files changed, 66 insertions, 0 deletions

diff --git a/Logs/Difference.hs b/Logs/Difference.hs
new file mode 100644
index 000000000..68d624f99
--- /dev/null
+++ b/Logs/Difference.hs
@@ -0,0 +1,40 @@
+{- git-annex difference log
+ -
+ - Copyright 2015 Joey Hess <id@joeyh.name>
+ -
+ - Licensed under the GNU GPL version 3 or higher.
+ -}
+
+module Logs.Difference (
+	recordDifferences,
+	recordedDifferences,
+	recordedDifferencesFor,
+	module Logs.Difference.Pure
+) where
+
+import Data.Monoid
+import Data.Time.Clock.POSIX
+import qualified Data.Map as M
+
+import Common.Annex
+import Types.Difference
+import qualified Annex.Branch
+import Logs
+import Logs.UUIDBased
+import Logs.Difference.Pure
+
+recordDifferences :: Differences -> UUID -> Annex ()
+recordDifferences differences uuid = do
+	ts <- liftIO getPOSIXTime
+	Annex.Branch.change differenceLog $
+		showLog id . changeLog ts uuid (show differences) . parseLog Just
+
+-- Map of UUIDs that have Differences recorded.
+-- If a new version of git-annex has added a Difference this version
+-- doesn't know about, it will contain UnknownDifferences.
+recordedDifferences :: Annex (M.Map UUID Differences)
+recordedDifferences = parseDifferencesLog <$> Annex.Branch.get differenceLog
+
+recordedDifferencesFor :: UUID -> Annex Differences
+recordedDifferencesFor u = fromMaybe mempty . M.lookup u 
+	<$> recordedDifferences
diff --git a/Logs/Difference/Pure.hs b/Logs/Difference/Pure.hs
new file mode 100644
index 000000000..76d995a01
--- /dev/null
+++ b/Logs/Difference/Pure.hs
@@ -0,0 +1,26 @@
+{- git-annex difference log, pure functions
+ -
+ - Copyright 2015 Joey Hess <id@joeyh.name>
+ -
+ - Licensed under the GNU GPL version 3 or higher.
+ -}
+
+module Logs.Difference.Pure (
+	allDifferences,
+	parseDifferencesLog,
+) where
+
+import Data.Monoid
+import qualified Data.Map as M
+
+import Common.Annex
+import Types.Difference
+import Logs.UUIDBased
+
+parseDifferencesLog :: String -> (M.Map UUID Differences)
+parseDifferencesLog = simpleMap 
+	. parseLog (Just . fromMaybe UnknownDifferences . readish)
+
+-- The sum of all recorded differences, across all UUIDs.
+allDifferences :: M.Map UUID Differences -> Differences
+allDifferences = mconcat . M.elems