broke out Git/Branch.hs and reorganized
This commit is contained in:
Joey Hess
parent
543d0d2501
commit
31a0c07ee9
2 changed files with 242 additions and 225 deletions
411
Annex/Branch.hs
411
Annex/Branch.hs
|
|
@ -6,15 +6,15 @@
|
||||||
-}
|
-}
|
||||||
|
|
||||||
module Annex.Branch (
|
module Annex.Branch (
|
||||||
|
name,
|
||||||
|
hasOrigin,
|
||||||
|
hasSibling,
|
||||||
create,
|
create,
|
||||||
update,
|
update,
|
||||||
get,
|
get,
|
||||||
change,
|
change,
|
||||||
commit,
|
commit,
|
||||||
files,
|
files,
|
||||||
name,
|
|
||||||
hasOrigin,
|
|
||||||
hasSibling,
|
|
||||||
) where
|
) where
|
||||||
|
|
||||||
import System.Exit
|
import System.Exit
|
||||||
|
|
@ -27,6 +27,7 @@ import Annex.Journal
|
||||||
import qualified Git
|
import qualified Git
|
||||||
import qualified Git.UnionMerge
|
import qualified Git.UnionMerge
|
||||||
import qualified Git.Ref
|
import qualified Git.Ref
|
||||||
|
import qualified Git.Branch
|
||||||
import Annex.CatFile
|
import Annex.CatFile
|
||||||
|
|
||||||
{- Name of the branch that is used to store git-annex's information. -}
|
{- Name of the branch that is used to store git-annex's information. -}
|
||||||
|
|
@ -41,57 +42,132 @@ fullname = Git.Ref $ "refs/heads/" ++ show name
|
||||||
originname :: Git.Ref
|
originname :: Git.Ref
|
||||||
originname = Git.Ref $ "origin/" ++ show name
|
originname = Git.Ref $ "origin/" ++ show name
|
||||||
|
|
||||||
{- Populates the branch's index file with the current branch contents.
|
{- Does origin/git-annex exist? -}
|
||||||
|
hasOrigin :: Annex Bool
|
||||||
|
hasOrigin = inRepo $ Git.Ref.exists originname
|
||||||
|
|
||||||
|
{- Does the git-annex branch or a sibling foo/git-annex branch exist? -}
|
||||||
|
hasSibling :: Annex Bool
|
||||||
|
hasSibling = not . null <$> siblingBranches
|
||||||
|
|
||||||
|
{- List of git-annex (refs, branches), including the main one and any
|
||||||
|
- from remotes. Duplicate refs are filtered out. -}
|
||||||
|
siblingBranches :: Annex [(Git.Ref, Git.Branch)]
|
||||||
|
siblingBranches = inRepo $ Git.Ref.matching name
|
||||||
|
|
||||||
|
{- Creates the branch, if it does not already exist. -}
|
||||||
|
create :: Annex ()
|
||||||
|
create = do
|
||||||
|
_ <- getBranch
|
||||||
|
return ()
|
||||||
|
|
||||||
|
{- Returns the ref of the branch, creating it first if necessary. -}
|
||||||
|
getBranch :: Annex (Git.Ref)
|
||||||
|
getBranch = maybe (hasOrigin >>= go >>= use) (return) =<< branchsha
|
||||||
|
where
|
||||||
|
go True = do
|
||||||
|
inRepo $ Git.run "branch"
|
||||||
|
[Param $ show name, Param $ show originname]
|
||||||
|
fromMaybe (error $ "failed to create " ++ show name)
|
||||||
|
<$> branchsha
|
||||||
|
go False = withIndex' True $ do
|
||||||
|
inRepo $ Git.commit "branch created" fullname []
|
||||||
|
use sha = do
|
||||||
|
setIndexSha sha
|
||||||
|
return sha
|
||||||
|
branchsha = inRepo $ Git.Ref.sha fullname
|
||||||
|
|
||||||
|
{- Ensures that the branch and index are is up-to-date; should be
|
||||||
|
- called before data is read from it. Runs only once per git-annex run.
|
||||||
-
|
-
|
||||||
- This is only done when the index doesn't yet exist, and the index
|
- Before refs are merged into the index, it's important to first stage the
|
||||||
- is used to build up changes to be commited to the branch, and merge
|
- journal into the index. Otherwise, any changes in the journal would
|
||||||
- in changes from other branches.
|
- later get staged, and might overwrite changes made during the merge.
|
||||||
-}
|
|
||||||
genIndex :: Git.Repo -> IO ()
|
|
||||||
genIndex g = Git.UnionMerge.stream_update_index g
|
|
||||||
[Git.UnionMerge.ls_tree fullname g]
|
|
||||||
|
|
||||||
{- Merges the specified branches into the index.
|
|
||||||
- Any changes staged in the index will be preserved. -}
|
|
||||||
mergeIndex :: [Git.Ref] -> Annex ()
|
|
||||||
mergeIndex branches = do
|
|
||||||
h <- catFileHandle
|
|
||||||
inRepo $ \g -> Git.UnionMerge.merge_index h g branches
|
|
||||||
|
|
||||||
{- 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
|
|
||||||
f <- fromRepo gitAnnexIndex
|
|
||||||
bracketIO (Git.useIndex f) id $ do
|
|
||||||
unlessM (liftIO $ doesFileExist f) $ do
|
|
||||||
unless bootstrapping create
|
|
||||||
liftIO $ createDirectoryIfMissing True $ takeDirectory f
|
|
||||||
unless bootstrapping $ inRepo genIndex
|
|
||||||
a
|
|
||||||
|
|
||||||
{- Updates the branch's index to reflect the current contents of the branch.
|
|
||||||
- Any changes staged in the index will be preserved.
|
|
||||||
-
|
-
|
||||||
- Compares the ref stored in the lock file with the current
|
- (It would be cleaner to handle the merge by updating the journal, not the
|
||||||
- ref of the branch to see if an update is needed.
|
- index, with changes from the branches.)
|
||||||
|
-
|
||||||
|
- The branch is fast-forwarded if possible, otherwise a merge commit is
|
||||||
|
- made.
|
||||||
-}
|
-}
|
||||||
updateIndex :: Git.Ref -> Annex ()
|
update :: Annex ()
|
||||||
updateIndex branchref = do
|
update = runUpdateOnce $ do
|
||||||
lock <- fromRepo gitAnnexIndexLock
|
-- ensure branch exists, and get its current ref
|
||||||
lockref <- Git.Ref . firstLine <$>
|
branchref <- getBranch
|
||||||
liftIO (catchDefaultIO (readFileStrict lock) "")
|
-- check what needs updating before taking the lock
|
||||||
when (lockref /= branchref) $ do
|
dirty <- journalDirty
|
||||||
withIndex $ mergeIndex [fullname]
|
(refs, branches) <- unzip <$> newerSiblings
|
||||||
setIndexSha branchref
|
if (not dirty && null refs)
|
||||||
|
then updateIndex branchref
|
||||||
|
else withIndex $ lockJournal $ do
|
||||||
|
when dirty stageJournal
|
||||||
|
let merge_desc = if null branches
|
||||||
|
then "update"
|
||||||
|
else "merging " ++
|
||||||
|
unwords (map Git.Ref.describe branches) ++
|
||||||
|
" into " ++ show name
|
||||||
|
unless (null branches) $ do
|
||||||
|
showSideAction merge_desc
|
||||||
|
mergeIndex branches
|
||||||
|
ff <- if dirty
|
||||||
|
then return False
|
||||||
|
else inRepo $ Git.Branch.fastForward fullname refs
|
||||||
|
if ff
|
||||||
|
then updateIndex branchref
|
||||||
|
else commitBranch branchref merge_desc
|
||||||
|
(nub $ fullname:refs)
|
||||||
|
invalidateCache
|
||||||
|
where
|
||||||
|
newerSiblings = filterM isnewer =<< siblingBranches
|
||||||
|
isnewer (_, b) = inRepo $ Git.Branch.changed fullname b
|
||||||
|
|
||||||
{- Record that the branch's index has been updated to correspond to a
|
{- Gets the content of a file on the branch, or content from the journal, or
|
||||||
- given ref of the branch. -}
|
- staged in the index.
|
||||||
setIndexSha :: Git.Ref -> Annex ()
|
-
|
||||||
setIndexSha ref = do
|
- Returns an empty string if the file doesn't exist yet. -}
|
||||||
lock <- fromRepo gitAnnexIndexLock
|
get :: FilePath -> Annex String
|
||||||
liftIO $ writeFile lock $ show ref ++ "\n"
|
get = get' False
|
||||||
|
|
||||||
|
{- Like get, but does not merge the branch, so the info returned may not
|
||||||
|
- reflect changes in remotes. (Changing the value this returns, and then
|
||||||
|
- merging is always the same as using get, and then changing its value.) -}
|
||||||
|
getStale :: FilePath -> Annex String
|
||||||
|
getStale = get' True
|
||||||
|
|
||||||
|
get' :: Bool -> FilePath -> Annex String
|
||||||
|
get' staleok file = fromcache =<< getCache file
|
||||||
|
where
|
||||||
|
fromcache (Just content) = return content
|
||||||
|
fromcache Nothing = fromjournal =<< getJournalFile file
|
||||||
|
fromjournal (Just content) = cache content
|
||||||
|
fromjournal Nothing
|
||||||
|
| staleok = withIndex frombranch
|
||||||
|
| otherwise = withIndexUpdate $ frombranch >>= cache
|
||||||
|
frombranch = L.unpack <$> catFile fullname file
|
||||||
|
cache content = do
|
||||||
|
setCache file content
|
||||||
|
return content
|
||||||
|
|
||||||
|
{- Applies a function to modifiy the content of a file.
|
||||||
|
-
|
||||||
|
- Note that this does not cause the branch to be merged, it only
|
||||||
|
- modifes the current content of the file on the branch.
|
||||||
|
-}
|
||||||
|
change :: FilePath -> (String -> String) -> Annex ()
|
||||||
|
change file a = lockJournal $ getStale file >>= return . a >>= set file
|
||||||
|
|
||||||
|
{- Records new content of a file into the journal and cache. -}
|
||||||
|
set :: FilePath -> String -> Annex ()
|
||||||
|
set file content = do
|
||||||
|
setJournalFile file content
|
||||||
|
setCache file content
|
||||||
|
|
||||||
|
{- Stages the journal, and commits staged changes to the branch. -}
|
||||||
|
commit :: String -> Annex ()
|
||||||
|
commit message = whenM journalDirty $ lockJournal $ do
|
||||||
|
stageJournal
|
||||||
|
ref <- getBranch
|
||||||
|
withIndex $ commitBranch ref message [fullname]
|
||||||
|
|
||||||
{- Commits the staged changes in the index to the branch.
|
{- Commits the staged changes in the index to the branch.
|
||||||
-
|
-
|
||||||
|
|
@ -141,183 +217,6 @@ commitBranch branchref message parents = do
|
||||||
|
|
||||||
racemessage = message ++ " (recovery from race)"
|
racemessage = message ++ " (recovery from race)"
|
||||||
|
|
||||||
{- Runs an action using the branch's index file, first making sure that
|
|
||||||
- the branch and index are up-to-date. -}
|
|
||||||
withIndexUpdate :: Annex a -> Annex a
|
|
||||||
withIndexUpdate a = update >> withIndex a
|
|
||||||
|
|
||||||
{- Creates the branch, if it does not already exist. -}
|
|
||||||
create :: Annex ()
|
|
||||||
create = do
|
|
||||||
_ <- getBranch
|
|
||||||
return ()
|
|
||||||
|
|
||||||
{- Returns the ref of the branch, creating it first if necessary. -}
|
|
||||||
getBranch :: Annex (Git.Ref)
|
|
||||||
getBranch = maybe (hasOrigin >>= go >>= use) (return) =<< branchsha
|
|
||||||
where
|
|
||||||
go True = do
|
|
||||||
inRepo $ Git.run "branch"
|
|
||||||
[Param $ show name, Param $ show originname]
|
|
||||||
fromMaybe (error $ "failed to create " ++ show name)
|
|
||||||
<$> branchsha
|
|
||||||
go False = withIndex' True $ do
|
|
||||||
inRepo $ Git.commit "branch created" fullname []
|
|
||||||
use sha = do
|
|
||||||
setIndexSha sha
|
|
||||||
return sha
|
|
||||||
branchsha = inRepo $ Git.Ref.sha fullname
|
|
||||||
|
|
||||||
{- Stages the journal, and commits staged changes to the branch. -}
|
|
||||||
commit :: String -> Annex ()
|
|
||||||
commit message = whenM journalDirty $ lockJournal $ do
|
|
||||||
stageJournal
|
|
||||||
ref <- getBranch
|
|
||||||
withIndex $ commitBranch ref message [fullname]
|
|
||||||
|
|
||||||
{- Ensures that the branch and index are is up-to-date; should be
|
|
||||||
- called before data is read from it. Runs only once per git-annex run.
|
|
||||||
-
|
|
||||||
- Before refs are merged into the index, it's important to first stage the
|
|
||||||
- journal into the index. Otherwise, any changes in the journal would
|
|
||||||
- later get staged, and might overwrite changes made during the merge.
|
|
||||||
-
|
|
||||||
- (It would be cleaner to handle the merge by updating the journal, not the
|
|
||||||
- index, with changes from the branches.)
|
|
||||||
-
|
|
||||||
- The branch is fast-forwarded if possible, otherwise a merge commit is
|
|
||||||
- made.
|
|
||||||
-}
|
|
||||||
update :: Annex ()
|
|
||||||
update = runUpdateOnce $ do
|
|
||||||
-- ensure branch exists, and get its current ref
|
|
||||||
branchref <- getBranch
|
|
||||||
-- check what needs updating before taking the lock
|
|
||||||
dirty <- journalDirty
|
|
||||||
c <- filterM (changedBranch fullname . snd) =<< siblingBranches
|
|
||||||
let (refs, branches) = unzip c
|
|
||||||
if (not dirty && null refs)
|
|
||||||
then updateIndex branchref
|
|
||||||
else withIndex $ lockJournal $ do
|
|
||||||
when dirty stageJournal
|
|
||||||
let merge_desc = if null branches
|
|
||||||
then "update"
|
|
||||||
else "merging " ++
|
|
||||||
unwords (map Git.Ref.describe branches) ++
|
|
||||||
" into " ++ show name
|
|
||||||
unless (null branches) $ do
|
|
||||||
showSideAction merge_desc
|
|
||||||
mergeIndex branches
|
|
||||||
ff <- if dirty then return False else tryFastForwardTo refs
|
|
||||||
if ff
|
|
||||||
then updateIndex branchref
|
|
||||||
else commitBranch branchref merge_desc
|
|
||||||
(nub $ fullname:refs)
|
|
||||||
invalidateCache
|
|
||||||
|
|
||||||
{- Checks if the second branch has any commits not present on the first
|
|
||||||
- branch. -}
|
|
||||||
changedBranch :: Git.Branch -> Git.Branch -> Annex Bool
|
|
||||||
changedBranch origbranch newbranch
|
|
||||||
| origbranch == newbranch = return False
|
|
||||||
| otherwise = not . L.null <$> diffs
|
|
||||||
where
|
|
||||||
diffs = inRepo $ Git.pipeRead
|
|
||||||
[ Param "log"
|
|
||||||
, Param (show origbranch ++ ".." ++ show 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
|
|
||||||
- fast-forward.
|
|
||||||
-
|
|
||||||
- In order for that to be possible, one of the refs must contain
|
|
||||||
- every commit present in all the other refs, as well as in the
|
|
||||||
- git-annex branch.
|
|
||||||
-}
|
|
||||||
tryFastForwardTo :: [Git.Ref] -> Annex Bool
|
|
||||||
tryFastForwardTo [] = return True
|
|
||||||
tryFastForwardTo (first:rest) = do
|
|
||||||
-- First, check that the git-annex branch does not contain any
|
|
||||||
-- new commits that are not in the first other branch. If it does,
|
|
||||||
-- cannot fast-forward.
|
|
||||||
diverged <- changedBranch first fullname
|
|
||||||
if diverged
|
|
||||||
then no_ff
|
|
||||||
else maybe no_ff do_ff =<< findbest first rest
|
|
||||||
where
|
|
||||||
no_ff = return False
|
|
||||||
do_ff branch = do
|
|
||||||
inRepo $ Git.run "update-ref"
|
|
||||||
[Param $ show fullname, Param $ show branch]
|
|
||||||
return True
|
|
||||||
findbest c [] = return $ Just c
|
|
||||||
findbest c (r:rs)
|
|
||||||
| c == r = findbest c rs
|
|
||||||
| otherwise = do
|
|
||||||
better <- changedBranch c r
|
|
||||||
worse <- changedBranch r c
|
|
||||||
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
|
|
||||||
|
|
||||||
{- Does origin/git-annex exist? -}
|
|
||||||
hasOrigin :: Annex Bool
|
|
||||||
hasOrigin = inRepo $ Git.Ref.exists originname
|
|
||||||
|
|
||||||
{- Does the git-annex branch or a sibling foo/git-annex branch exist? -}
|
|
||||||
hasSibling :: Annex Bool
|
|
||||||
hasSibling = not . null <$> siblingBranches
|
|
||||||
|
|
||||||
{- List of git-annex (refs, branches), including the main one and any
|
|
||||||
- from remotes. Duplicate refs are filtered out. -}
|
|
||||||
siblingBranches :: Annex [(Git.Ref, Git.Branch)]
|
|
||||||
siblingBranches = inRepo $ Git.Ref.matching name
|
|
||||||
|
|
||||||
{- Applies a function to modifiy the content of a file.
|
|
||||||
-
|
|
||||||
- Note that this does not cause the branch to be merged, it only
|
|
||||||
- modifes the current content of the file on the branch.
|
|
||||||
-}
|
|
||||||
change :: FilePath -> (String -> String) -> Annex ()
|
|
||||||
change file a = lockJournal $ getStale file >>= return . a >>= set file
|
|
||||||
|
|
||||||
{- Records new content of a file into the journal and cache. -}
|
|
||||||
set :: FilePath -> String -> Annex ()
|
|
||||||
set file content = do
|
|
||||||
setJournalFile file content
|
|
||||||
setCache file content
|
|
||||||
|
|
||||||
{- Gets the content of a file on the branch, or content from the journal, or
|
|
||||||
- staged in the index.
|
|
||||||
-
|
|
||||||
- Returns an empty string if the file doesn't exist yet. -}
|
|
||||||
get :: FilePath -> Annex String
|
|
||||||
get = get' False
|
|
||||||
|
|
||||||
{- Like get, but does not merge the branch, so the info returned may not
|
|
||||||
- reflect changes in remotes. (Changing the value this returns, and then
|
|
||||||
- merging is always the same as using get, and then changing its value.) -}
|
|
||||||
getStale :: FilePath -> Annex String
|
|
||||||
getStale = get' True
|
|
||||||
|
|
||||||
get' :: Bool -> FilePath -> Annex String
|
|
||||||
get' staleok file = fromcache =<< getCache file
|
|
||||||
where
|
|
||||||
fromcache (Just content) = return content
|
|
||||||
fromcache Nothing = fromjournal =<< getJournalFile file
|
|
||||||
fromjournal (Just content) = cache content
|
|
||||||
fromjournal Nothing
|
|
||||||
| staleok = withIndex frombranch
|
|
||||||
| otherwise = withIndexUpdate $ frombranch >>= cache
|
|
||||||
frombranch = L.unpack <$> catFile fullname file
|
|
||||||
cache content = do
|
|
||||||
setCache file content
|
|
||||||
return content
|
|
||||||
|
|
||||||
{- Lists all files on the branch. There may be duplicates in the list. -}
|
{- Lists all files on the branch. There may be duplicates in the list. -}
|
||||||
files :: Annex [FilePath]
|
files :: Annex [FilePath]
|
||||||
files = withIndexUpdate $ do
|
files = withIndexUpdate $ do
|
||||||
|
|
@ -326,6 +225,64 @@ files = withIndexUpdate $ do
|
||||||
jfiles <- getJournalledFiles
|
jfiles <- getJournalledFiles
|
||||||
return $ jfiles ++ bfiles
|
return $ jfiles ++ bfiles
|
||||||
|
|
||||||
|
|
||||||
|
{- Populates the branch's index file with the current branch contents.
|
||||||
|
-
|
||||||
|
- This is only done when the index doesn't yet exist, and the index
|
||||||
|
- is used to build up changes to be commited to the branch, and merge
|
||||||
|
- in changes from other branches.
|
||||||
|
-}
|
||||||
|
genIndex :: Git.Repo -> IO ()
|
||||||
|
genIndex g = Git.UnionMerge.stream_update_index g
|
||||||
|
[Git.UnionMerge.ls_tree fullname g]
|
||||||
|
|
||||||
|
{- Merges the specified branches into the index.
|
||||||
|
- Any changes staged in the index will be preserved. -}
|
||||||
|
mergeIndex :: [Git.Ref] -> Annex ()
|
||||||
|
mergeIndex branches = do
|
||||||
|
h <- catFileHandle
|
||||||
|
inRepo $ \g -> Git.UnionMerge.merge_index h g branches
|
||||||
|
|
||||||
|
{- 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
|
||||||
|
f <- fromRepo gitAnnexIndex
|
||||||
|
bracketIO (Git.useIndex f) id $ do
|
||||||
|
unlessM (liftIO $ doesFileExist f) $ do
|
||||||
|
unless bootstrapping create
|
||||||
|
liftIO $ createDirectoryIfMissing True $ takeDirectory f
|
||||||
|
unless bootstrapping $ inRepo genIndex
|
||||||
|
a
|
||||||
|
|
||||||
|
{- Runs an action using the branch's index file, first making sure that
|
||||||
|
- the branch and index are up-to-date. -}
|
||||||
|
withIndexUpdate :: Annex a -> Annex a
|
||||||
|
withIndexUpdate a = update >> withIndex a
|
||||||
|
|
||||||
|
{- Updates the branch's index to reflect the current contents of the branch.
|
||||||
|
- Any changes staged in the index will be preserved.
|
||||||
|
-
|
||||||
|
- Compares the ref stored in the lock file with the current
|
||||||
|
- ref of the branch to see if an update is needed.
|
||||||
|
-}
|
||||||
|
updateIndex :: Git.Ref -> Annex ()
|
||||||
|
updateIndex branchref = do
|
||||||
|
lock <- fromRepo gitAnnexIndexLock
|
||||||
|
lockref <- Git.Ref . firstLine <$>
|
||||||
|
liftIO (catchDefaultIO (readFileStrict lock) "")
|
||||||
|
when (lockref /= branchref) $ do
|
||||||
|
withIndex $ mergeIndex [fullname]
|
||||||
|
setIndexSha branchref
|
||||||
|
|
||||||
|
{- Record that the branch's index has been updated to correspond to a
|
||||||
|
- given ref of the branch. -}
|
||||||
|
setIndexSha :: Git.Ref -> Annex ()
|
||||||
|
setIndexSha ref = do
|
||||||
|
lock <- fromRepo gitAnnexIndexLock
|
||||||
|
liftIO $ writeFile lock $ show ref ++ "\n"
|
||||||
|
|
||||||
{- Stages the journal into the index. -}
|
{- Stages the journal into the index. -}
|
||||||
stageJournal :: Annex ()
|
stageJournal :: Annex ()
|
||||||
stageJournal = do
|
stageJournal = do
|
||||||
|
|
|
||||||
60
Git/Branch.hs
Normal file
60
Git/Branch.hs
Normal file
|
|
@ -0,0 +1,60 @@
|
||||||
|
{- 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
|
||||||
|
|
||||||
|
{- 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 = Git.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
|
||||||
|
Git.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
|
||||||
Loading…
Reference in a new issue