{- management of the git-annex branch - - Copyright 2011-2022 Joey Hess - - Licensed under the GNU AGPL version 3 or higher. -} {-# LANGUAGE OverloadedStrings #-} module Annex.Branch ( fullname, name, hasOrigin, hasSibling, siblingBranches, create, UpdateMade(..), update, forceUpdate, updateTo, get, getHistorical, getUnmergedRefs, RegardingUUID(..), change, ChangeOrAppend(..), changeOrAppend, maybeChange, commitMessage, createMessage, commit, forceCommit, files, rememberTreeish, performTransitions, withIndex, precache, overBranchFileContents, ) where import qualified Data.ByteString as B import qualified Data.ByteString.Lazy as L import qualified Data.ByteString.Char8 as B8 import qualified Data.Set as S import qualified Data.Map as M import Data.Function import Data.Char import Data.ByteString.Builder import Control.Concurrent (threadDelay) import Control.Concurrent.MVar import qualified System.FilePath.ByteString as P import Annex.Common hiding (append) import Types.BranchState import Annex.BranchState import Annex.Journal import Annex.GitOverlay import Annex.Tmp import qualified Git import qualified Git.Command import qualified Git.Ref import qualified Git.RefLog import qualified Git.Sha import qualified Git.Branch import qualified Git.UnionMerge import qualified Git.UpdateIndex import qualified Git.Tree import qualified Git.LsTree import Git.LsTree (lsTreeParams) import qualified Git.HashObject import Annex.HashObject import Git.Types (Ref(..), fromRef, fromRef', RefDate, TreeItemType(..)) import Git.FilePath import Annex.CatFile import Git.CatFile (catObjectStreamLsTree) import Annex.Perms import Logs import Logs.Transitions import Logs.File import Logs.Trust.Pure import Logs.Remote.Pure import Logs.Export.Pure import Logs.Difference.Pure import qualified Annex.Queue import Types.Transitions import Annex.Branch.Transitions import qualified Annex import Annex.Hook import Utility.Directory.Stream import Utility.Tmp import qualified Utility.RawFilePath as R {- Name of the branch that is used to store git-annex's information. -} name :: Git.Ref name = Git.Ref "git-annex" {- Fully qualified name of the branch. -} fullname :: Git.Ref fullname = Git.Ref $ "refs/heads/" <> fromRef' name {- Branch's name in origin. -} originname :: Git.Ref originname = Git.Ref $ "refs/remotes/origin/" <> fromRef' name {- 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 (shas, branches), including the main one and any - from remotes. Duplicates are filtered out. -} siblingBranches :: Annex [(Git.Sha, Git.Branch)] siblingBranches = inRepo $ Git.Ref.matchingUniq [name] {- Creates the branch, if it does not already exist. -} create :: Annex () create = void getBranch {- 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.Command.run [ Param "branch" , Param "--no-track" , Param $ fromRef name , Param $ fromRef originname ] fromMaybe (error $ "failed to create " ++ fromRef name) <$> branchsha go False = withIndex' True $ do -- Create the index file. This is not necessary, -- except to avoid a bug in git that causes -- git write-tree to segfault when the index file does not -- exist. inRepo $ flip Git.UpdateIndex.streamUpdateIndex [] cmode <- annexCommitMode <$> Annex.getGitConfig cmessage <- createMessage inRepo $ Git.Branch.commitAlways cmode cmessage fullname [] use sha = do setIndexSha sha return sha branchsha = inRepo $ Git.Ref.sha fullname {- Ensures that the branch and index are up-to-date; should be - called before data is read from it. Runs only once per git-annex run. -} update :: Annex BranchState update = runUpdateOnce $ updateTo =<< siblingBranches {- Forces an update even if one has already been run. -} forceUpdate :: Annex UpdateMade forceUpdate = updateTo =<< siblingBranches {- Merges the specified Refs into the index, if they have any changes not - already in it. The Branch names are only used in the commit message; - it's even possible that the provided Branches have not been updated to - point to the Refs yet. - - The branch is fast-forwarded if possible, otherwise a merge commit is - made. - - 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. - This is only done if some of the Refs do need to be merged. - - Also handles performing any Transitions that have not yet been - performed, in either the local branch, or the Refs. -} updateTo :: [(Git.Sha, Git.Branch)] -> Annex UpdateMade updateTo pairs = ifM (annexMergeAnnexBranches <$> Annex.getGitConfig) ( updateTo' pairs , return (UpdateMade False False) ) updateTo' :: [(Git.Sha, Git.Branch)] -> Annex UpdateMade updateTo' pairs = do -- ensure branch exists, and get its current ref branchref <- getBranch ignoredrefs <- getIgnoredRefs let unignoredrefs = excludeset ignoredrefs pairs tomerge <- if null unignoredrefs then return [] else do mergedrefs <- getMergedRefs filterM isnewer (excludeset mergedrefs unignoredrefs) {- In a read-only repository, catching permission denied lets - query operations still work, although they will need to do - additional work since the refs are not merged. -} catchPermissionDenied (const (updatefailedperms tomerge)) (go branchref tomerge) where excludeset s = filter (\(r, _) -> S.notMember r s) isnewer (r, _) = inRepo $ Git.Branch.changed fullname r go branchref tomerge = do dirty <- journalDirty gitAnnexJournalDir journalcleaned <- if null tomerge {- Even when no refs need to be merged, the index - may still be updated if the branch has gotten ahead - of the index, or just if the journal is dirty. -} then ifM (needUpdateIndex branchref) ( lockJournal $ \jl -> do forceUpdateIndex jl branchref {- When there are journalled changes - as well as the branch being updated, - a commit needs to be done. -} when dirty $ go' branchref dirty [] jl return True , if dirty then ifM (annexAlwaysCommit <$> Annex.getGitConfig) ( lockJournal $ \jl -> do go' branchref dirty [] jl return True , return False ) else return True ) else lockJournal $ \jl -> do go' branchref dirty tomerge jl return True journalclean <- if journalcleaned then not <$> privateUUIDsKnown else pure False return $ UpdateMade { refsWereMerged = not (null tomerge) , journalClean = journalclean } go' branchref dirty tomerge jl = stagejournalwhen dirty jl $ do let (refs, branches) = unzip tomerge merge_desc <- if null tomerge then commitMessage else return $ "merging " ++ unwords (map Git.Ref.describe branches) ++ " into " ++ fromRef name localtransitions <- getLocalTransitions unless (null tomerge) $ do showSideAction merge_desc mapM_ checkBranchDifferences refs mergeIndex jl refs let commitrefs = nub $ fullname:refs ifM (handleTransitions jl localtransitions commitrefs) ( runAnnexHook postUpdateAnnexHook , do ff <- if dirty then return False else inRepo $ Git.Branch.fastForward fullname refs if ff then updateIndex jl branchref else commitIndex jl branchref merge_desc commitrefs ) addMergedRefs tomerge invalidateCache stagejournalwhen dirty jl a | dirty = stageJournal jl a | otherwise = withIndex a -- Preparing for read-only branch access with unmerged remote refs. updatefailedperms tomerge = do let refs = map fst tomerge -- Gather any transitions that are new to either the -- local branch or a remote ref, which will need to be -- applied on the fly. localts <- getLocalTransitions remotets <- mapM getRefTransitions refs ts <- if all (localts ==) remotets then return [] else let tcs = mapMaybe getTransitionCalculator $ knownTransitionList $ combineTransitions (localts:remotets) in if null tcs then return [] else do config <- Annex.getGitConfig trustmap <- calcTrustMap <$> getStaged trustLog remoteconfigmap <- calcRemoteConfigMap <$> getStaged remoteLog return $ map (\c -> c trustmap remoteconfigmap config) tcs return $ UpdateFailedPermissions { refsUnmerged = refs , newTransitions = ts } {- Gets the content of a file, which may be in the journal, or in the index - (and committed to the branch). - - Returns an empty string if the file doesn't exist yet. - - Updates the branch if necessary, to ensure the most up-to-date available - content is returned. - - When permissions prevented updating the branch, reads the content from the - journal, plus the branch, plus all unmerged refs. In this case, any - transitions that have not been applied to all refs will be applied on - the fly. -} get :: RawFilePath -> Annex L.ByteString get file = do st <- update case getCache file st of Just content -> return content Nothing -> do content <- if journalIgnorable st then getRef fullname file else if null (unmergedRefs st) then getLocal file else unmergedbranchfallback st setCache file content return content where unmergedbranchfallback st = do l <- getLocal file bs <- forM (unmergedRefs st) $ \ref -> getRef ref file let content = l <> mconcat bs return $ applytransitions (unhandledTransitions st) content applytransitions [] content = content applytransitions (changer:rest) content = case changer file content of PreserveFile -> applytransitions rest content ChangeFile builder -> do let content' = toLazyByteString builder if L.null content' -- File is deleted, can't run any other -- transitions on it. then content' else applytransitions rest content' {- When the git-annex branch is unable to be updated due to permissions, - and there are other git-annex branches that have not been merged into - it, this gets the refs of those branches. -} getUnmergedRefs :: Annex [Git.Ref] getUnmergedRefs = unmergedRefs <$> update {- Used to cache the value of a file, which has been read from the branch - using some optimised method. The journal has to be checked, in case - it has a newer version of the file that has not reached the branch yet. -} precache :: RawFilePath -> L.ByteString -> Annex () precache file branchcontent = do st <- getState content <- if journalIgnorable st then pure branchcontent else getJournalFileStale (GetPrivate True) file >>= return . \case NoJournalledContent -> branchcontent JournalledContent journalcontent -> journalcontent PossiblyStaleJournalledContent journalcontent -> branchcontent <> journalcontent setCache file content {- Like get, but does not merge the branch, so the info returned may not - reflect changes in remotes. - (Changing the value this returns, and then merging is always the - same as using get, and then changing its value.) -} getLocal :: RawFilePath -> Annex L.ByteString getLocal = getLocal' (GetPrivate True) getLocal' :: GetPrivate -> RawFilePath -> Annex L.ByteString getLocal' getprivate file = do fastDebug "Annex.Branch" ("read " ++ fromRawFilePath file) go =<< getJournalFileStale getprivate file where go NoJournalledContent = getRef fullname file go (JournalledContent journalcontent) = return journalcontent go (PossiblyStaleJournalledContent journalcontent) = do v <- getRef fullname file return (v <> journalcontent) {- Gets the content of a file as staged in the branch's index. -} getStaged :: RawFilePath -> Annex L.ByteString getStaged = getRef indexref where -- This makes git cat-file be run with ":file", -- so it looks at the index. indexref = Ref "" getHistorical :: RefDate -> RawFilePath -> Annex L.ByteString getHistorical date file = -- This check avoids some ugly error messages when the reflog -- is empty. ifM (null <$> inRepo (Git.RefLog.get' [Param (fromRef fullname), Param "-n1"])) ( giveup ("No reflog for " ++ fromRef fullname) , getRef (Git.Ref.dateRef fullname date) file ) getRef :: Ref -> RawFilePath -> Annex L.ByteString getRef ref file = withIndex $ catFile ref file {- Applies a function to modify the content of a file. - - Note that this does not cause the branch to be merged, it only - modifies the current content of the file on the branch. -} change :: Journalable content => RegardingUUID -> RawFilePath -> (L.ByteString -> content) -> Annex () change ru file f = lockJournal $ \jl -> f <$> getToChange ru file >>= set jl ru file {- Applies a function which can modify the content of a file, or not. -} maybeChange :: Journalable content => RegardingUUID -> RawFilePath -> (L.ByteString -> Maybe content) -> Annex () maybeChange ru file f = lockJournal $ \jl -> do v <- getToChange ru file case f v of Just jv -> let b = journalableByteString jv in when (v /= b) $ set jl ru file b _ -> noop data ChangeOrAppend t = Change t | Append t {- Applies a function that can either modify the content of the file, - or append to the file. Appending can be more efficient when several - lines are written to a file in succession. - - When annex.alwayscompact=false, the function is not passed the content - of the journal file when the journal file already exists, and whatever - value it provides is always appended to the journal file. That avoids - reading the journal file, and so can be faster when many lines are being - written to it. The information that is recorded will be effectively the - same, only obsolete log lines will not get compacted. - - Currently, only appends when annex.alwayscompact=false. That is to - avoid appending when an older version of git-annex is also in use in the - same repository. An interrupted append could leave the journal file in a - state that would confuse the older version. This is planned to be - changed in a future repository version. -} changeOrAppend :: Journalable content => RegardingUUID -> RawFilePath -> (L.ByteString -> ChangeOrAppend content) -> Annex () changeOrAppend ru file f = lockJournal $ \jl -> checkCanAppendJournalFile jl ru file >>= \case Just appendable -> ifM (annexAlwaysCompact <$> Annex.getGitConfig) ( do oldc <- getToChange ru file case f oldc of Change newc -> set jl ru file newc Append toappend -> set jl ru file $ oldc <> journalableByteString toappend -- Use this instead in v11 -- or whatever. -- append jl file appendable toappend , case f mempty of -- Append even though a change was -- requested; since mempty was passed in, -- the lines requested to change are -- minimized. Change newc -> append jl file appendable newc Append toappend -> append jl file appendable toappend ) Nothing -> do oldc <- getToChange ru file case f oldc of Change newc -> set jl ru file newc -- Journal file does not exist yet, so -- cannot append and have to write it all. Append toappend -> set jl ru file $ oldc <> journalableByteString toappend {- Only get private information when the RegardingUUID is itself private. -} getToChange :: RegardingUUID -> RawFilePath -> Annex L.ByteString getToChange ru f = flip getLocal' f . GetPrivate =<< regardingPrivateUUID ru {- Records new content of a file into the journal. - - This is not exported; all changes have to be made via change. This - ensures that information that was written to the branch is not - overwritten. Also, it avoids a get followed by a set without taking into - account whether private information was gotten from the private - git-annex index, and should not be written to the public git-annex - branch. -} set :: Journalable content => JournalLocked -> RegardingUUID -> RawFilePath -> content -> Annex () set jl ru f c = do journalChanged setJournalFile jl ru f c fastDebug "Annex.Branch" ("set " ++ fromRawFilePath f) -- Could cache the new content, but it would involve -- evaluating a Journalable Builder twice, which is not very -- efficient. Instead, assume that it's not common to need to read -- a log file immediately after writing it. invalidateCache {- Appends content to the journal file. -} append :: Journalable content => JournalLocked -> RawFilePath -> AppendableJournalFile -> content -> Annex () append jl f appendable toappend = do journalChanged appendJournalFile jl appendable toappend fastDebug "Annex.Branch" ("append " ++ fromRawFilePath f) invalidateCache {- Commit message used when making a commit of whatever data has changed - to the git-annex branch. -} commitMessage :: Annex String commitMessage = fromMaybe "update" . annexCommitMessage <$> Annex.getGitConfig {- Commit message used when creating the branch. -} createMessage :: Annex String createMessage = fromMaybe "branch created" . annexCommitMessage <$> Annex.getGitConfig {- Stages the journal, and commits staged changes to the branch. -} commit :: String -> Annex () commit = whenM (journalDirty gitAnnexJournalDir) . forceCommit {- Commits the current index to the branch even without any journalled - changes. -} forceCommit :: String -> Annex () forceCommit message = lockJournal $ \jl -> stageJournal jl $ do ref <- getBranch commitIndex jl ref message [fullname] {- Commits the staged changes in the index to the branch. - - Ensures that the branch's index file is first updated to merge the state - of the branch at branchref, before running the commit action. This - is needed because the branch may have had changes pushed to it, that - are not yet reflected in the index. - - The branchref value can have been obtained using getBranch at any - previous point, though getting it a long time ago makes the race - more likely to occur. - - Note that changes may be pushed to the branch at any point in time! - So, there's a race. If the commit is made using the newly pushed tip of - the branch as its parent, and that ref has not yet been merged into the - index, then the result is that the commit will revert the pushed - changes, since they have not been merged into the index. This race - is detected and another commit made to fix it. - - (It's also possible for the branch to be overwritten, - losing the commit made here. But that's ok; the data is still in the - index and will get committed again later.) -} commitIndex :: JournalLocked -> Git.Ref -> String -> [Git.Ref] -> Annex () commitIndex jl branchref message parents = do showStoringStateAction commitIndex' jl branchref message message 0 parents commitIndex' :: JournalLocked -> Git.Ref -> String -> String -> Integer -> [Git.Ref] -> Annex () commitIndex' jl branchref message basemessage retrynum parents = do updateIndex jl branchref cmode <- annexCommitMode <$> Annex.getGitConfig committedref <- inRepo $ Git.Branch.commitAlways cmode message fullname parents setIndexSha committedref parentrefs <- commitparents <$> catObject committedref when (racedetected branchref parentrefs) $ fixrace committedref parentrefs where -- look for "parent ref" lines and return the refs commitparents = map (Git.Ref . snd) . filter isparent . map (toassoc . L.toStrict) . L.split newline newline = fromIntegral (ord '\n') toassoc = separate' (== (fromIntegral (ord ' '))) isparent (k,_) = k == "parent" {- The race can be detected by checking the commit's - parent, which will be the newly pushed branch, - instead of the expected ref that the index was updated to. -} racedetected expectedref parentrefs | expectedref `elem` parentrefs = False -- good parent | otherwise = True -- race! {- To recover from the race, union merge the lost refs - into the index. -} fixrace committedref lostrefs = do showSideAction "recovering from race" let retrynum' = retrynum+1 -- small sleep to let any activity that caused -- the race settle down liftIO $ threadDelay (100000 + fromInteger retrynum') mergeIndex jl lostrefs let racemessage = basemessage ++ " (recovery from race #" ++ show retrynum' ++ "; expected commit parent " ++ show branchref ++ " but found " ++ show lostrefs ++ " )" commitIndex' jl committedref racemessage basemessage retrynum' [committedref] {- Lists all files on the branch. including ones in the journal - that have not been committed yet. - - There may be duplicates in the list, when the journal has files that - have not been written to the branch yet. - - In a read-only repository that has other git-annex branches that have - not been merged in, returns Nothing, because it's not possible to - efficiently handle that. -} files :: Annex (Maybe ([RawFilePath], IO Bool)) files = do st <- update if not (null (unmergedRefs st)) then return Nothing else do (bfs, cleanup) <- branchFiles -- ++ forces the content of the first list to be -- buffered in memory, so use journalledFiles, -- which should be much smaller most of the time. -- branchFiles will stream as the list is consumed. l <- (++) <$> journalledFiles <*> pure bfs return (Just (l, cleanup)) {- Lists all files currently in the journal. There may be duplicates in - the list when using a private journal. -} journalledFiles :: Annex [RawFilePath] journalledFiles = ifM privateUUIDsKnown ( (++) <$> getJournalledFilesStale gitAnnexPrivateJournalDir <*> getJournalledFilesStale gitAnnexJournalDir , getJournalledFilesStale gitAnnexJournalDir ) {- Files in the branch, not including any from journalled changes, - and without updating the branch. -} branchFiles :: Annex ([RawFilePath], IO Bool) branchFiles = withIndex $ inRepo branchFiles' branchFiles' :: Git.Repo -> IO ([RawFilePath], IO Bool) branchFiles' = Git.Command.pipeNullSplit' $ lsTreeParams Git.LsTree.LsTreeRecursive (Git.LsTree.LsTreeLong False) fullname [Param "--name-only"] {- 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 committed to the branch, and merge - in changes from other branches. -} genIndex :: Git.Repo -> IO () genIndex g = Git.UpdateIndex.streamUpdateIndex g [Git.UpdateIndex.lsTree fullname g] {- Merges the specified refs into the index. - Any changes staged in the index will be preserved. -} mergeIndex :: JournalLocked -> [Git.Ref] -> Annex () mergeIndex jl branches = do prepareModifyIndex jl withHashObjectHandle $ \hashhandle -> withCatFileHandle $ \ch -> inRepo $ \g -> Git.UnionMerge.mergeIndex hashhandle ch g branches {- Removes any stale git lock file, to avoid git falling over when - updating the index. - - Since all modifications of the index are performed inside this module, - and only when the journal is locked, the fact that the journal has to be - locked when this is called ensures that no other process is currently - modifying the index. So any index.lock file must be stale, caused - by git running when the system crashed, or the repository's disk was - removed, etc. -} prepareModifyIndex :: JournalLocked -> Annex () prepareModifyIndex _jl = do index <- fromRepo gitAnnexIndex void $ liftIO $ tryIO $ R.removeLink (index <> ".lock") {- 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 = withIndexFile AnnexIndexFile $ \f -> do checkIndexOnce $ unlessM (liftIO $ doesFileExist f) $ do unless bootstrapping create createAnnexDirectory $ toRawFilePath $ 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 - ref of the branch to see if an update is needed. -} updateIndex :: JournalLocked -> Git.Ref -> Annex () updateIndex jl branchref = whenM (needUpdateIndex branchref) $ forceUpdateIndex jl branchref forceUpdateIndex :: JournalLocked -> Git.Ref -> Annex () forceUpdateIndex jl branchref = do withIndex $ mergeIndex jl [fullname] setIndexSha branchref {- Checks if the index needs to be updated. -} needUpdateIndex :: Git.Ref -> Annex Bool needUpdateIndex branchref = do f <- fromRawFilePath <$> fromRepo gitAnnexIndexStatus committedref <- Git.Ref . firstLine' <$> liftIO (catchDefaultIO mempty $ B.readFile f) return (committedref /= 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 f <- fromRepo gitAnnexIndexStatus writeLogFile f $ fromRef ref ++ "\n" runAnnexHook postUpdateAnnexHook {- Stages the journal into the index, and runs an action that - commits the index to the branch. Note that the action is run - inside withIndex so will automatically use the branch's index. - - Before staging, this removes any existing git index file lock. - This is safe to do because stageJournal is the only thing that - modifies this index file, and only one can run at a time, because - the journal is locked. So any existing git index file lock must be - stale, and the journal must contain any data that was in the process - of being written to the index file when it crashed. -} stageJournal :: JournalLocked -> Annex () -> Annex () stageJournal jl commitindex = withIndex $ withOtherTmp $ \tmpdir -> do prepareModifyIndex jl g <- gitRepo let dir = gitAnnexJournalDir g (jlogf, jlogh) <- openjlog (fromRawFilePath tmpdir) withHashObjectHandle $ \h -> withJournalHandle gitAnnexJournalDir $ \jh -> Git.UpdateIndex.streamUpdateIndex g [genstream dir h jh jlogh] commitindex liftIO $ cleanup (fromRawFilePath dir) jlogh jlogf where genstream dir h jh jlogh streamer = readDirectory jh >>= \case Nothing -> return () Just file -> do unless (dirCruft file) $ do let path = dir P. toRawFilePath file sha <- Git.HashObject.hashFile h path hPutStrLn jlogh file streamer $ Git.UpdateIndex.updateIndexLine sha TreeFile (asTopFilePath $ fileJournal $ toRawFilePath file) genstream dir h jh jlogh streamer -- Clean up the staged files, as listed in the temp log file. -- The temp file is used to avoid needing to buffer all the -- filenames in memory. cleanup dir jlogh jlogf = do hFlush jlogh hSeek jlogh AbsoluteSeek 0 stagedfs <- lines <$> hGetContents jlogh mapM_ (removeFile . (dir )) stagedfs hClose jlogh removeWhenExistsWith (R.removeLink) (toRawFilePath jlogf) openjlog tmpdir = liftIO $ openTmpFileIn tmpdir "jlog" getLocalTransitions :: Annex Transitions getLocalTransitions = parseTransitionsStrictly "local" <$> getLocal transitionsLog {- This is run after the refs have been merged into the index, - but before the result is committed to the branch. - (Which is why it's passed the contents of the local branches's - transition log before that merge took place.) - - When the refs contain transitions that have not yet been done locally, - the transitions are performed on the index, and a new branch - is created from the result. - - When there are transitions recorded locally that have not been done - to the remote refs, the transitions are performed in the index, - and committed to the existing branch. In this case, the untransitioned - remote refs cannot be merged into the branch (since transitions - throw away history), so they are added to the list of refs to ignore, - to avoid re-merging content from them again. -} handleTransitions :: JournalLocked -> Transitions -> [Git.Ref] -> Annex Bool handleTransitions jl localts refs = do remotets <- mapM getRefTransitions refs if all (localts ==) remotets then return False else do let m = M.fromList (zip refs remotets) let allts = combineTransitions (localts:remotets) let (transitionedrefs, untransitionedrefs) = partition (\r -> M.lookup r m == Just allts) refs performTransitionsLocked jl allts (localts /= allts) transitionedrefs ignoreRefs untransitionedrefs return True {- Performs the specified transitions on the contents of the index file, - commits it to the branch, or creates a new branch. -} performTransitions :: Transitions -> Bool -> [Ref] -> Annex () performTransitions ts neednewlocalbranch transitionedrefs = lockJournal $ \jl -> performTransitionsLocked jl ts neednewlocalbranch transitionedrefs performTransitionsLocked :: JournalLocked -> Transitions -> Bool -> [Ref] -> Annex () performTransitionsLocked jl ts neednewlocalbranch transitionedrefs = do -- For simplicity & speed, we're going to use the Annex.Queue to -- update the git-annex branch, while it usually holds changes -- for the head branch. Flush any such changes. Annex.Queue.flush -- Stop any running git cat-files, to ensure that the -- getStaged calls below use the current index, and not some older -- one. catFileStop withIndex $ do prepareModifyIndex jl run $ mapMaybe getTransitionCalculator tlist Annex.Queue.flush if neednewlocalbranch then do cmode <- annexCommitMode <$> Annex.getGitConfig committedref <- inRepo $ Git.Branch.commitAlways cmode message fullname transitionedrefs setIndexSha committedref else do ref <- getBranch commitIndex jl ref message (nub $ fullname:transitionedrefs) regraftexports where message | neednewlocalbranch && null transitionedrefs = "new branch for transition " ++ tdesc | otherwise = "continuing transition " ++ tdesc tdesc = show $ map describeTransition tlist tlist = knownTransitionList ts {- The changes to make to the branch are calculated and applied to - the branch directly, rather than going through the journal, - which would be innefficient. (And the journal is not designed - to hold changes to every file in the branch at once.) - - When a file in the branch is changed by transition code, - its new content is remembered and fed into the code for subsequent - transitions. -} run [] = noop run changers = do config <- Annex.getGitConfig trustmap <- calcTrustMap <$> getStaged trustLog remoteconfigmap <- calcRemoteConfigMap <$> getStaged remoteLog -- partially apply, improves performance let changers' = map (\c -> c trustmap remoteconfigmap config) changers (fs, cleanup) <- branchFiles forM_ fs $ \f -> do content <- getStaged f apply changers' f content liftIO $ void cleanup apply [] _ _ = return () apply (changer:rest) file content = case changer file content of PreserveFile -> apply rest file content ChangeFile builder -> do let content' = toLazyByteString builder if L.null content' then do Annex.Queue.addUpdateIndex =<< inRepo (Git.UpdateIndex.unstageFile file) -- File is deleted; can't run any other -- transitions on it. return () else do sha <- hashBlob content' Annex.Queue.addUpdateIndex $ Git.UpdateIndex.pureStreamer $ Git.UpdateIndex.updateIndexLine sha TreeFile (asTopFilePath file) apply rest file content' -- Trees mentioned in export.log were grafted into the old -- git-annex branch to make sure they remain available. Re-graft -- the trees into the new branch. regraftexports = do l <- exportedTreeishes . M.elems . parseExportLogMap <$> getStaged exportLog forM_ l $ \t -> rememberTreeishLocked t (asTopFilePath exportTreeGraftPoint) jl checkBranchDifferences :: Git.Ref -> Annex () checkBranchDifferences ref = do theirdiffs <- allDifferences . parseDifferencesLog <$> catFile ref differenceLog mydiffs <- annexDifferences <$> Annex.getGitConfig when (theirdiffs /= mydiffs) $ giveup "Remote repository is tuned in incompatible way; cannot be merged with local repository." ignoreRefs :: [Git.Sha] -> Annex () ignoreRefs rs = do old <- getIgnoredRefs let s = S.unions [old, S.fromList rs] f <- fromRepo gitAnnexIgnoredRefs writeLogFile f $ unlines $ map fromRef $ S.elems s getIgnoredRefs :: Annex (S.Set Git.Sha) getIgnoredRefs = S.fromList . mapMaybe Git.Sha.extractSha . B8.lines <$> content where content = do f <- fromRawFilePath <$> fromRepo gitAnnexIgnoredRefs liftIO $ catchDefaultIO mempty $ B.readFile f addMergedRefs :: [(Git.Sha, Git.Branch)] -> Annex () addMergedRefs [] = return () addMergedRefs new = do old <- getMergedRefs' -- Keep only the newest sha for each branch. let l = nubBy ((==) `on` snd) (new ++ old) f <- fromRepo gitAnnexMergedRefs writeLogFile f $ unlines $ map (\(s, b) -> fromRef s ++ '\t' : fromRef b) l getMergedRefs :: Annex (S.Set Git.Sha) getMergedRefs = S.fromList . map fst <$> getMergedRefs' getMergedRefs' :: Annex [(Git.Sha, Git.Branch)] getMergedRefs' = do f <- fromRawFilePath <$> fromRepo gitAnnexMergedRefs s <- liftIO $ catchDefaultIO mempty $ B.readFile f return $ map parse $ B8.lines s where parse l = let (s, b) = separate' (== (fromIntegral (ord '\t'))) l in (Ref s, Ref b) {- Grafts a treeish into the branch at the specified location, - and then removes it. This ensures that the treeish won't get garbage - collected, and will always be available as long as the git-annex branch - is available. -} rememberTreeish :: Git.Ref -> TopFilePath -> Annex () rememberTreeish treeish graftpoint = lockJournal $ rememberTreeishLocked treeish graftpoint rememberTreeishLocked :: Git.Ref -> TopFilePath -> JournalLocked -> Annex () rememberTreeishLocked treeish graftpoint jl = do branchref <- getBranch updateIndex jl branchref origtree <- fromMaybe (giveup "unable to determine git-annex branch tree") <$> inRepo (Git.Ref.tree branchref) addedt <- inRepo $ Git.Tree.graftTree treeish graftpoint origtree cmode <- annexCommitMode <$> Annex.getGitConfig c <- inRepo $ Git.Branch.commitTree cmode "graft" [branchref] addedt c' <- inRepo $ Git.Branch.commitTree cmode "graft cleanup" [c] origtree inRepo $ Git.Branch.update' fullname c' -- The tree in c' is the same as the tree in branchref, -- and the index was updated to that above, so it's safe to -- say that the index contains c'. setIndexSha c' {- Runs an action on the content of selected files from the branch. - This is much faster than reading the content of each file in turn, - because it lets git cat-file stream content without blocking. - - The action is passed a callback that it can repeatedly call to read - the next file and its contents. When there are no more files, the - callback will return Nothing. - - In some cases the callback may return the same file more than once, - with different content. This happens rarely, only when the journal - contains additional information, and the last version of the - file it returns is the most current one. - - In a read-only repository that has other git-annex branches that have - not been merged in, returns Nothing, because it's not possible to - efficiently handle that. -} overBranchFileContents :: (RawFilePath -> Maybe v) -> (Annex (Maybe (v, RawFilePath, Maybe L.ByteString)) -> Annex a) -> Annex (Maybe a) overBranchFileContents select go = do st <- update if not (null (unmergedRefs st)) then return Nothing else Just <$> overBranchFileContents' select go st overBranchFileContents' :: (RawFilePath -> Maybe v) -> (Annex (Maybe (v, RawFilePath, Maybe L.ByteString)) -> Annex a) -> BranchState -> Annex a overBranchFileContents' select go st = do g <- Annex.gitRepo (l, cleanup) <- inRepo $ Git.LsTree.lsTree Git.LsTree.LsTreeRecursive (Git.LsTree.LsTreeLong False) fullname let select' f = fmap (\v -> (v, f)) (select f) buf <- liftIO newEmptyMVar let go' reader = go $ liftIO reader >>= \case Just ((v, f), content) -> do content' <- checkjournal f content return (Just (v, f, content')) Nothing | journalIgnorable st -> return Nothing -- The journal did not get committed to the -- branch, and may contain files that -- are not present in the branch, which -- need to be provided to the action still. -- This can cause the action to be run a -- second time with a file it already ran on. | otherwise -> liftIO (tryTakeMVar buf) >>= \case Nothing -> drain buf =<< journalledFiles Just fs -> drain buf fs catObjectStreamLsTree l (select' . getTopFilePath . Git.LsTree.file) g go' `finally` liftIO (void cleanup) where -- Check the journal, in case it did not get committed to the branch checkjournal f branchcontent | journalIgnorable st = return branchcontent | otherwise = getJournalFileStale (GetPrivate True) f >>= return . \case NoJournalledContent -> branchcontent JournalledContent journalledcontent -> Just journalledcontent PossiblyStaleJournalledContent journalledcontent -> Just (fromMaybe mempty branchcontent <> journalledcontent) drain buf fs = case getnext fs of Just (v, f, fs') -> do liftIO $ putMVar buf fs' content <- getJournalFileStale (GetPrivate True) f >>= \case NoJournalledContent -> return Nothing JournalledContent journalledcontent -> return (Just journalledcontent) PossiblyStaleJournalledContent journalledcontent -> do -- This is expensive, but happens -- only when there is a private -- journal file. content <- getRef fullname f return (Just (content <> journalledcontent)) return (Just (v, f, content)) Nothing -> do liftIO $ putMVar buf [] return Nothing getnext [] = Nothing getnext (f:fs) = case select f of Nothing -> getnext fs Just v -> Just (v, f, fs)