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|
{- adjusted branch
-
- Copyright 2016 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Annex.AdjustedBranch (
Adjustment(..),
OrigBranch,
AdjBranch,
originalToAdjusted,
adjustedToOriginal,
fromAdjustedBranch,
getAdjustment,
enterAdjustedBranch,
adjustBranch,
adjustToCrippledFileSystem,
updateAdjustedBranch,
propigateAdjustedCommits,
checkAdjustedClone,
) where
import Annex.Common
import qualified Annex
import Git
import Git.Types
import qualified Git.Branch
import qualified Git.Ref
import qualified Git.Command
import qualified Git.Tree
import qualified Git.DiffTree
import Git.Tree (TreeItem(..))
import Git.Sha
import Git.Env
import Git.Index
import Git.FilePath
import qualified Git.LockFile
import Annex.CatFile
import Annex.Link
import Annex.AutoMerge
import Annex.Content
import qualified Database.Keys
import qualified Data.Map as M
data Adjustment
= UnlockAdjustment
| LockAdjustment
| HideMissingAdjustment
| ShowMissingAdjustment
deriving (Show, Eq)
reverseAdjustment :: Adjustment -> Adjustment
reverseAdjustment UnlockAdjustment = LockAdjustment
reverseAdjustment LockAdjustment = UnlockAdjustment
reverseAdjustment HideMissingAdjustment = ShowMissingAdjustment
reverseAdjustment ShowMissingAdjustment = HideMissingAdjustment
{- How to perform various adjustments to a TreeItem. -}
adjustTreeItem :: Adjustment -> TreeItem -> Annex (Maybe TreeItem)
adjustTreeItem UnlockAdjustment ti@(TreeItem f m s)
| toBlobType m == Just SymlinkBlob = do
mk <- catKey s
case mk of
Just k -> do
Database.Keys.addAssociatedFile k f
Just . TreeItem f (fromBlobType FileBlob)
<$> hashPointerFile k
Nothing -> return (Just ti)
| otherwise = return (Just ti)
adjustTreeItem LockAdjustment ti@(TreeItem f m s)
| toBlobType m /= Just SymlinkBlob = do
mk <- catKey s
case mk of
Just k -> do
absf <- inRepo $ \r -> absPath $
fromTopFilePath f r
linktarget <- calcRepo $ gitAnnexLink absf k
Just . TreeItem f (fromBlobType SymlinkBlob)
<$> hashSymlink linktarget
Nothing -> return (Just ti)
| otherwise = return (Just ti)
adjustTreeItem HideMissingAdjustment ti@(TreeItem _ _ s) = do
mk <- catKey s
case mk of
Just k -> ifM (inAnnex k)
( return (Just ti)
, return Nothing
)
Nothing -> return (Just ti)
adjustTreeItem ShowMissingAdjustment ti = return (Just ti)
type OrigBranch = Branch
type AdjBranch = Branch
adjustedBranchPrefix :: String
adjustedBranchPrefix = "refs/heads/adjusted/"
serialize :: Adjustment -> String
serialize UnlockAdjustment = "unlocked"
serialize LockAdjustment = "locked"
serialize HideMissingAdjustment = "present"
serialize ShowMissingAdjustment = "showmissing"
deserialize :: String -> Maybe Adjustment
deserialize "unlocked" = Just UnlockAdjustment
deserialize "locked" = Just UnlockAdjustment
deserialize "present" = Just HideMissingAdjustment
deserialize _ = Nothing
originalToAdjusted :: OrigBranch -> Adjustment -> AdjBranch
originalToAdjusted orig adj = Ref $
adjustedBranchPrefix ++ base ++ '(' : serialize adj ++ ")"
where
base = fromRef (Git.Ref.basename orig)
adjustedToOriginal :: AdjBranch -> Maybe (Adjustment, OrigBranch)
adjustedToOriginal b
| adjustedBranchPrefix `isPrefixOf` bs = do
let (base, as) = separate (== '(') (drop prefixlen bs)
adj <- deserialize (takeWhile (/= ')') as)
Just (adj, Git.Ref.under "refs/heads" (Ref base))
| otherwise = Nothing
where
bs = fromRef b
prefixlen = length adjustedBranchPrefix
getAdjustment :: Branch -> Maybe Adjustment
getAdjustment = fmap fst . adjustedToOriginal
fromAdjustedBranch :: Branch -> OrigBranch
fromAdjustedBranch b = maybe b snd (adjustedToOriginal b)
originalBranch :: Annex (Maybe OrigBranch)
originalBranch = fmap fromAdjustedBranch <$> inRepo Git.Branch.current
{- Enter an adjusted version of current branch (or, if already in an
- adjusted version of a branch, changes the adjustment of the original
- branch).
-
- Can fail, if no branch is checked out, or perhaps if staged changes
- conflict with the adjusted branch.
-}
enterAdjustedBranch :: Adjustment -> Annex ()
enterAdjustedBranch adj = go =<< originalBranch
where
go (Just origbranch) = do
adjbranch <- preventCommits $ const $
adjustBranch adj origbranch
showOutput -- checkout can have output in large repos
inRepo $ Git.Command.run
[ Param "checkout"
, Param $ fromRef $ Git.Ref.base $ adjbranch
]
go Nothing = error "not on any branch!"
adjustToCrippledFileSystem :: Annex ()
adjustToCrippledFileSystem = do
warning "Entering an adjusted branch where files are unlocked as this filesystem does not support locked files."
whenM (isNothing <$> originalBranch) $
void $ inRepo $ Git.Branch.commitCommand Git.Branch.AutomaticCommit
[ Param "--quiet"
, Param "--allow-empty"
, Param "-m"
, Param "commit before entering adjusted unlocked branch"
]
enterAdjustedBranch UnlockAdjustment
adjustBranch :: Adjustment -> OrigBranch -> Annex AdjBranch
adjustBranch adj origbranch = do
sha <- adjust adj origbranch
inRepo $ Git.Branch.update "entering adjusted branch" adjbranch sha
return adjbranch
where
adjbranch = originalToAdjusted origbranch adj
adjust :: Adjustment -> Ref -> Annex Sha
adjust adj orig = do
treesha <- adjustTree adj orig
commitAdjustedTree treesha orig
adjustTree :: Adjustment -> Ref -> Annex Sha
adjustTree adj orig = do
let toadj = adjustTreeItem adj
treesha <- Git.Tree.adjustTree toadj [] [] orig =<< Annex.gitRepo
return treesha
type CommitsPrevented = Git.LockFile.LockHandle
{- Locks git's index file, preventing git from making a commit, merge,
- or otherwise changing the HEAD ref while the action is run.
-
- Throws an IO exception if the index file is already locked.
-}
preventCommits :: (CommitsPrevented -> Annex a) -> Annex a
preventCommits = bracket setup cleanup
where
setup = do
lck <- fromRepo indexFileLock
liftIO $ Git.LockFile.openLock lck
cleanup = liftIO . Git.LockFile.closeLock
{- Commits a given adjusted tree, with the provided parent ref.
-
- This should always yield the same value, even if performed in different
- clones of a repo, at different times. The commit message and other
- metadata is based on the parent.
-}
commitAdjustedTree :: Sha -> Ref -> Annex Sha
commitAdjustedTree treesha parent = commitAdjustedTree' treesha parent [parent]
commitAdjustedTree' :: Sha -> Ref -> [Ref] -> Annex Sha
commitAdjustedTree' treesha basis parents = go =<< catCommit basis
where
go Nothing = inRepo mkcommit
go (Just basiscommit) = inRepo $ commitWithMetaData
(commitAuthorMetaData basiscommit)
(commitCommitterMetaData basiscommit)
mkcommit
mkcommit = Git.Branch.commitTree Git.Branch.AutomaticCommit
adjustedBranchCommitMessage parents treesha
adjustedBranchCommitMessage :: String
adjustedBranchCommitMessage = "git-annex adjusted branch"
{- Update the currently checked out adjusted branch, merging the provided
- branch into it. -}
updateAdjustedBranch :: Branch -> (OrigBranch, Adjustment) -> Git.Branch.CommitMode -> Annex Bool
updateAdjustedBranch tomerge (origbranch, adj) commitmode = catchBoolIO $
join $ preventCommits $ \commitsprevented -> go commitsprevented =<< (,)
<$> inRepo (Git.Ref.sha tomerge)
<*> inRepo Git.Branch.current
where
go commitsprevented (Just mergesha, Just currbranch) =
ifM (inRepo $ Git.Branch.changed currbranch mergesha)
( do
void $ propigateAdjustedCommits' origbranch (adj, currbranch) commitsprevented
adjustedtomerge <- adjust adj mergesha
ifM (inRepo $ Git.Branch.changed currbranch adjustedtomerge)
( return $
-- Run after commit lock is dropped.
ifM (autoMergeFrom adjustedtomerge (Just currbranch) commitmode)
( preventCommits $ \_ ->
recommit currbranch mergesha =<< catCommit currbranch
, return False
)
, nochangestomerge
)
, nochangestomerge
)
go _ _ = return $ return False
nochangestomerge = return $ return True
{- A merge commit has been made on the adjusted branch.
- Now, re-do it, removing the old version of the adjusted branch
- from its history.
-
- There are two possible scenarios; either some commits
- were made on top of the adjusted branch's adjusting commit,
- or not. Those commits have already been propigated to the
- orig branch, so we can just check if there are commits in the
- orig branch that are not present in tomerge.
-}
recommit currbranch mergedsha (Just mergecommit) =
ifM (inRepo $ Git.Branch.changed tomerge origbranch)
( remerge currbranch mergedsha mergecommit
=<< inRepo (Git.Ref.sha origbranch)
, fastforward currbranch mergedsha mergecommit
)
recommit _ _ Nothing = return False
{- Fast-forward scenario. The mergecommit is changed to a non-merge
- commit, with its parent being the mergedsha.
- The orig branch can simply be pointed at the mergedsha.
-}
fastforward currbranch mergedsha mergecommit = do
commitsha <- commitAdjustedTree (commitTree mergecommit) mergedsha
inRepo $ Git.Branch.update "fast-forward update of adjusted branch" currbranch commitsha
inRepo $ Git.Branch.update "updating original branch" origbranch mergedsha
return True
{- True merge scenario. -}
remerge currbranch mergedsha mergecommit (Just origsha) = do
-- Update origbranch by reverse adjusting the mergecommit,
-- yielding a merge between orig and tomerge.
treesha <- reverseAdjustedTree origsha adj
-- get 1-parent commit because
-- reverseAdjustedTree does not support merges
=<< commitAdjustedTree (commitTree mergecommit) origsha
revadjcommit <- inRepo $
Git.Branch.commitTree Git.Branch.AutomaticCommit
("Merge branch " ++ fromRef tomerge) [origsha, mergedsha] treesha
inRepo $ Git.Branch.update "updating original branch" origbranch revadjcommit
-- Update currbranch, reusing mergedsha, but making its
-- parent be the updated origbranch.
adjcommit <- commitAdjustedTree' (commitTree mergecommit) revadjcommit [revadjcommit]
inRepo $ Git.Branch.update rebaseOnTopMsg currbranch adjcommit
return True
remerge _ _ _ Nothing = return False
{- Check for any commits present on the adjusted branch that have not yet
- been propigated to the orig branch, and propigate them.
-
- After propigating the commits back to the orig banch,
- rebase the adjusted branch on top of the updated orig branch.
-}
propigateAdjustedCommits :: OrigBranch -> (Adjustment, AdjBranch) -> Annex ()
propigateAdjustedCommits origbranch (adj, currbranch) =
preventCommits $ \commitsprevented -> do
join $ propigateAdjustedCommits' origbranch (adj, currbranch) commitsprevented
{- Returns action which will rebase the adjusted branch on top of the
- updated orig branch. -}
propigateAdjustedCommits'
:: OrigBranch
-> (Adjustment, AdjBranch)
-> CommitsPrevented
-> Annex (Annex ())
propigateAdjustedCommits' origbranch (adj, currbranch) _commitsprevented = do
ov <- inRepo $ Git.Ref.sha (Git.Ref.under "refs/heads" origbranch)
case ov of
Just origsha -> do
cv <- catCommit currbranch
case cv of
Just currcommit -> do
v <- newcommits >>= go origsha False
case v of
Left e -> do
warning e
return $ return ()
Right newparent -> return $
rebase currcommit newparent
Nothing -> return $ return ()
Nothing -> return $ return ()
where
newcommits = inRepo $ Git.Branch.changedCommits origbranch currbranch
-- Get commits oldest first, so they can be processed
-- in order made.
[Param "--reverse"]
go parent _ [] = do
inRepo $ Git.Branch.update "updating adjusted branch" origbranch parent
return (Right parent)
go parent pastadjcommit (sha:l) = do
mc <- catCommit sha
case mc of
Just c
| commitMessage c == adjustedBranchCommitMessage ->
go parent True l
| pastadjcommit -> do
v <- reverseAdjustedCommit parent adj (sha, c) origbranch
case v of
Left e -> return (Left e)
Right commit -> go commit pastadjcommit l
_ -> go parent pastadjcommit l
rebase currcommit newparent = do
-- Reuse the current adjusted tree,
-- and reparent it on top of the new
-- version of the origbranch.
commitAdjustedTree (commitTree currcommit) newparent
>>= inRepo . Git.Branch.update rebaseOnTopMsg currbranch
rebaseOnTopMsg :: String
rebaseOnTopMsg = "rebasing adjusted branch on top of updated original branch"
{- Reverses an adjusted commit, and commit with provided commitparent,
- yielding a commit sha.
-
- Adjusts the tree of the commitparent, changing only the files that the
- commit changed, and reverse adjusting those changes.
-
- The commit message, and the author and committer metadata are
- copied over from the basiscommit. However, any gpg signature
- will be lost, and any other headers are not copied either. -}
reverseAdjustedCommit :: Sha -> Adjustment -> (Sha, Commit) -> OrigBranch -> Annex (Either String Sha)
reverseAdjustedCommit commitparent adj (csha, basiscommit) origbranch
| length (commitParent basiscommit) > 1 = return $
Left $ "unable to propigate merge commit " ++ show csha ++ " back to " ++ show origbranch
| otherwise = do
treesha <- reverseAdjustedTree commitparent adj csha
revadjcommit <- inRepo $ commitWithMetaData
(commitAuthorMetaData basiscommit)
(commitCommitterMetaData basiscommit) $
Git.Branch.commitTree Git.Branch.AutomaticCommit
(commitMessage basiscommit) [commitparent] treesha
return (Right revadjcommit)
{- Adjusts the tree of the basis, changing only the files that the
- commit changed, and reverse adjusting those changes.
-
- commitDiff does not support merge commits, so the csha must not be a
- merge commit. -}
reverseAdjustedTree :: Sha -> Adjustment -> Sha -> Annex Sha
reverseAdjustedTree basis adj csha = do
(diff, cleanup) <- inRepo (Git.DiffTree.commitDiff csha)
let (adds, others) = partition (\dti -> Git.DiffTree.srcsha dti == nullSha) diff
let (removes, changes) = partition (\dti -> Git.DiffTree.dstsha dti == nullSha) others
adds' <- catMaybes <$>
mapM (adjustTreeItem reverseadj) (map diffTreeToTreeItem adds)
treesha <- Git.Tree.adjustTree
(propchanges changes)
adds'
(map Git.DiffTree.file removes)
basis
=<< Annex.gitRepo
void $ liftIO cleanup
return treesha
where
reverseadj = reverseAdjustment adj
propchanges changes ti@(TreeItem f _ _) =
case M.lookup f m of
Nothing -> return (Just ti) -- not changed
Just change -> adjustTreeItem reverseadj change
where
m = M.fromList $ map (\i@(TreeItem f' _ _) -> (f', i)) $
map diffTreeToTreeItem changes
diffTreeToTreeItem :: Git.DiffTree.DiffTreeItem -> TreeItem
diffTreeToTreeItem dti = TreeItem
(Git.DiffTree.file dti)
(Git.DiffTree.dstmode dti)
(Git.DiffTree.dstsha dti)
{- Cloning a repository that has an adjusted branch checked out will
- result in the clone having the same adjusted branch checked out -- but
- the origbranch won't exist in the clone. Create the origbranch. -}
checkAdjustedClone :: Annex ()
checkAdjustedClone = go =<< inRepo Git.Branch.current
where
go Nothing = return ()
go (Just currbranch) = case adjustedToOriginal currbranch of
Nothing -> return ()
Just (_adj, origbranch) ->
unlessM (inRepo $ Git.Ref.exists origbranch) $ do
let remotebranch = Git.Ref.underBase "refs/remotes/origin" origbranch
inRepo $ Git.Branch.update' origbranch remotebranch
|