reorder repo parameters last

Many functions took the repo as their first parameter. Changing it
consistently to be the last parameter allows doing some useful things with
currying, that reduce boilerplate.

In particular, g <- gitRepo is almost never needed now, instead
use inRepo to run an IO action in the repo, and fromRepo to get
a value from the repo.

This also provides more opportunities to use monadic and applicative
combinators.

1 files changed, 24 insertions, 36 deletions

diff --git a/Annex/Branch.hs b/Annex/Branch.hs
index 163c9ec60..189289ad3 100644
--- a/Annex/Branch.hs
+++ b/Annex/Branch.hs
@@ -56,21 +56,19 @@ index g = gitAnnexDir g </> "index"
  - and merge in changes from other branches.
  -}
 genIndex :: Git.Repo -> IO ()
-genIndex g = Git.UnionMerge.ls_tree g fullname >>= Git.UnionMerge.update_index g
+genIndex g = Git.UnionMerge.ls_tree fullname g >>= Git.UnionMerge.update_index g
 
 {- Runs an action using the branch's index file. -}
 withIndex :: Annex a -> Annex a
 withIndex = withIndex' False
 withIndex' :: Bool -> Annex a -> Annex a
 withIndex' bootstrapping a = do
-	g <- gitRepo
-	let f = index g
-
+	f <- fromRepo $ index
 	bracketIO (Git.useIndex f) id $ do
 		unlessM (liftIO $ doesFileExist f) $ do
 			unless bootstrapping create
 			liftIO $ createDirectoryIfMissing True $ takeDirectory f
-			unless bootstrapping $ liftIO $ genIndex g
+			unless bootstrapping $ inRepo genIndex
 		a
 
 withIndexUpdate :: Annex a -> Annex a
@@ -103,19 +101,17 @@ getCache file = getState >>= go
 {- Creates the branch, if it does not already exist. -}
 create :: Annex ()
 create = unlessM hasBranch $ do
-	g <- gitRepo
 	e <- hasOrigin
 	if e
-		then liftIO $ Git.run g "branch" [Param name, Param originname]
+		then inRepo $ Git.run "branch" [Param name, Param originname]
 		else withIndex' True $
-			liftIO $ Git.commit g "branch created" fullname []
+			inRepo $ Git.commit "branch created" fullname []
 
 {- Stages the journal, and commits staged changes to the branch. -}
 commit :: String -> Annex ()
 commit message = whenM journalDirty $ lockJournal $ do
 	stageJournalFiles
-	g <- gitRepo
-	withIndex $ liftIO $ Git.commit g message fullname [fullname]
+	withIndex $ inRepo $ Git.commit message fullname [fullname]
 
 {- Ensures that the branch is up-to-date; should be called before data is
  - read from it. Runs only once per git-annex run.
@@ -134,7 +130,6 @@ commit message = whenM journalDirty $ lockJournal $ do
  -}
 update :: Annex ()
 update = onceonly $ do
-	g <- gitRepo
 	-- check what needs updating before taking the lock
 	dirty <- journalDirty
 	c <- filterM (changedBranch name . snd) =<< siblingBranches
@@ -151,10 +146,10 @@ update = onceonly $ do
 			 - documentation advises users not to directly
 			 - modify the branch.
 			 -}
-			liftIO $ Git.UnionMerge.merge_index g branches
+			inRepo $ \g -> Git.UnionMerge.merge_index g branches
 		ff <- if dirty then return False else tryFastForwardTo refs
-		unless ff $
-			liftIO $ Git.commit g "update" fullname (nub $ fullname:refs)
+		unless ff $ inRepo $
+			Git.commit "update" fullname (nub $ fullname:refs)
 		invalidateCache
 	where
 		onceonly a = unlessM (branchUpdated <$> getState) $ do
@@ -165,14 +160,13 @@ update = onceonly $ do
 {- Checks if the second branch has any commits not present on the first
  - branch. -}
 changedBranch :: String -> String -> Annex Bool
-changedBranch origbranch newbranch = do
-	g <- gitRepo
-	diffs <- liftIO $ Git.pipeRead g [
-		Param "log",
-		Param (origbranch ++ ".." ++ newbranch),
-		Params "--oneline -n1"
-		]
-	return $ not $ L.null diffs
+changedBranch origbranch newbranch = not . L.null <$> diffs
+	where
+		diffs = inRepo $ Git.pipeRead
+			[ Param "log"
+			, Param (origbranch ++ ".." ++ newbranch)
+			, Params "--oneline -n1"
+			]
 
 {- Given a set of refs that are all known to have commits not
  - on the git-annex branch, tries to update the branch by a
@@ -195,8 +189,7 @@ tryFastForwardTo (first:rest) = do
 	where
 		no_ff = return False
 		do_ff branch = do
-			g <- gitRepo
-			liftIO $ Git.run g "update-ref" [Param fullname, Param branch]
+			inRepo $ Git.run "update-ref" [Param fullname, Param branch]
 			return True
 		findbest c [] = return $ Just c
 		findbest c (r:rs)
@@ -223,10 +216,8 @@ disableUpdate = Annex.changeState setupdated
 
 {- Checks if a git ref exists. -}
 refExists :: GitRef -> Annex Bool
-refExists ref = do
-	g <- gitRepo
-	liftIO $ Git.runBool g "show-ref"
-		[Param "--verify", Param "-q", Param ref]
+refExists ref = inRepo $ Git.runBool "show-ref"
+	[Param "--verify", Param "-q", Param ref]
 
 {- Does the main git-annex branch exist? -}
 hasBranch :: Annex Bool
@@ -244,8 +235,7 @@ hasSomeBranch = not . null <$> siblingBranches
  - from remotes. Duplicate refs are filtered out. -}
 siblingBranches :: Annex [(String, String)]
 siblingBranches = do
-	g <- gitRepo
-	r <- liftIO $ Git.pipeRead g [Param "show-ref", Param name]
+	r <- inRepo $ Git.pipeRead [Param "show-ref", Param name]
 	return $ nubBy uref $ map (pair . words . L.unpack) (L.lines r)
 	where
 		pair l = (head l, last l)
@@ -280,8 +270,7 @@ get file = fromcache =<< getCache file
 {- Lists all files on the branch. There may be duplicates in the list. -}
 files :: Annex [FilePath]
 files = withIndexUpdate $ do
-	g <- gitRepo
-	bfiles <- liftIO $ Git.pipeNullSplit g
+	bfiles <- inRepo $ Git.pipeNullSplit
 		[Params "ls-tree --name-only -r -z", Param fullname]
 	jfiles <- getJournalledFiles
 	return $ jfiles ++ bfiles
@@ -349,8 +338,8 @@ stageJournalFiles = do
 	where
 		index_lines shas = map genline . zip shas
 		genline (sha, file) = Git.UnionMerge.update_index_line sha file
-		git_hash_object g = Git.gitCommandLine g
-			[Param "hash-object", Param "-w", Param "--stdin-paths"]
+		git_hash_object g = Git.gitCommandLine
+			[Param "hash-object", Param "-w", Param "--stdin-paths"] g
 
 
 {- Checks if there are changes in the journal. -}
@@ -379,8 +368,7 @@ fileJournal = replace "//" "_" . replace "_" "/"
  - contention with other git-annex processes. -}
 lockJournal :: Annex a -> Annex a
 lockJournal a = do
-	g <- gitRepo
-	let file = gitAnnexJournalLock g
+	file <- fromRepo $ gitAnnexJournalLock
 	bracketIO (lock file) unlock a
 	where
 		lock file = do