79 lines
2.4 KiB
Haskell
79 lines
2.4 KiB
Haskell
{- git branch stuff
|
|
-
|
|
- Copyright 2011 Joey Hess <joey@kitenet.net>
|
|
-
|
|
- Licensed under the GNU GPL version 3 or higher.
|
|
-}
|
|
|
|
module Git.Branch where
|
|
|
|
import qualified Data.ByteString.Lazy.Char8 as L
|
|
|
|
import Common
|
|
import Git
|
|
import Git.Sha
|
|
import Git.Command
|
|
|
|
{- Checks if the second branch has any commits not present on the first
|
|
- branch. -}
|
|
changed :: Branch -> Branch -> Repo -> IO Bool
|
|
changed origbranch newbranch repo
|
|
| origbranch == newbranch = return False
|
|
| otherwise = not . L.null <$> diffs
|
|
where
|
|
diffs = pipeRead
|
|
[ Param "log"
|
|
, Param (show origbranch ++ ".." ++ show newbranch)
|
|
, Params "--oneline -n1"
|
|
] repo
|
|
|
|
{- Given a set of refs that are all known to have commits not
|
|
- on the branch, tries to update the branch by a fast-forward.
|
|
-
|
|
- In order for that to be possible, one of the refs must contain
|
|
- every commit present in all the other refs.
|
|
-}
|
|
fastForward :: Branch -> [Ref] -> Repo -> IO Bool
|
|
fastForward _ [] _ = return True
|
|
fastForward branch (first:rest) repo = do
|
|
-- First, check that the branch does not contain any
|
|
-- new commits that are not in the first ref. If it does,
|
|
-- cannot fast-forward.
|
|
diverged <- changed first branch repo
|
|
if diverged
|
|
then no_ff
|
|
else maybe no_ff do_ff =<< findbest first rest
|
|
where
|
|
no_ff = return False
|
|
do_ff to = do
|
|
run "update-ref"
|
|
[Param $ show branch, Param $ show to] repo
|
|
return True
|
|
findbest c [] = return $ Just c
|
|
findbest c (r:rs)
|
|
| c == r = findbest c rs
|
|
| otherwise = do
|
|
better <- changed c r repo
|
|
worse <- changed r c repo
|
|
case (better, worse) of
|
|
(True, True) -> return Nothing -- divergent fail
|
|
(True, False) -> findbest r rs -- better
|
|
(False, True) -> findbest c rs -- worse
|
|
(False, False) -> findbest c rs -- same
|
|
|
|
{- Commits the index into the specified branch (or other ref),
|
|
- with the specified parent refs, and returns the committed sha -}
|
|
commit :: String -> Branch -> [Ref] -> Repo -> IO Sha
|
|
commit message branch parentrefs repo = do
|
|
tree <- getSha "write-tree" $ asString $
|
|
pipeRead [Param "write-tree"] repo
|
|
sha <- getSha "commit-tree" $ asString $
|
|
ignorehandle $ pipeWriteRead
|
|
(map Param $ ["commit-tree", show tree] ++ ps)
|
|
(L.pack message) repo
|
|
run "update-ref" [Param $ show branch, Param $ show sha] repo
|
|
return sha
|
|
where
|
|
ignorehandle a = snd <$> a
|
|
asString a = L.unpack <$> a
|
|
ps = concatMap (\r -> ["-p", show r]) parentrefs
|