git-annex/Command/Undo.hs
Joey Hess 5e4deb3620
support sha256 git repos
Git will eventually switch to sha2 and there will not be one single
shaSize anymore, but two (40 and 64).

Changed all parsers for git plumbing output to support both sizes of
shas.

One potential problem this does not deal with is, if somewhere in
git-annex it reads two shas from different sources, and compares them
to see if they're the same sha, it would fail if they're sha1 and sha256
of the same value. I don't know if that will really be a concern.
2020-01-07 12:22:19 -04:00

73 lines
2.1 KiB
Haskell

{- git-annex command
-
- Copyright 2014 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
module Command.Undo where
import Command
import Git.DiffTree
import Git.FilePath
import Git.UpdateIndex
import Git.Sha
import qualified Git.LsFiles as LsFiles
import qualified Git.Command as Git
import qualified Git.Branch
import qualified Command.Sync
cmd :: Command
cmd = notBareRepo $
command "undo" SectionCommon
"undo last change to a file or directory"
paramPaths (withParams seek)
seek :: CmdParams -> CommandSeek
seek ps = do
-- Safety first; avoid any undo that would touch files that are not
-- in the index.
(fs, cleanup) <- inRepo $ LsFiles.notInRepo False (map toRawFilePath ps)
unless (null fs) $
giveup $ "Cannot undo changes to files that are not checked into git: " ++ unwords (map fromRawFilePath fs)
void $ liftIO $ cleanup
-- Committing staged changes before undo allows later
-- undoing the undo. It would be nicer to only commit staged
-- changes to the specified files, rather than all staged changes.
void $ Command.Sync.commitStaged Git.Branch.ManualCommit
"commit before undo"
withStrings (commandAction . start) ps
start :: FilePath -> CommandStart
start p = starting "undo" (ActionItemOther (Just p)) $
perform p
perform :: FilePath -> CommandPerform
perform p = do
g <- gitRepo
-- Get the reversed diff that needs to be applied to undo.
(diff, cleanup) <- inRepo $
diffLog [Param "-R", Param "--", Param p]
top <- inRepo $ toTopFilePath $ toRawFilePath p
let diff' = filter (`isDiffOf` top) diff
liftIO $ streamUpdateIndex g (map stageDiffTreeItem diff')
-- Take two passes through the diff, first doing any removals,
-- and then any adds. This order is necessary to handle eg, removing
-- a directory and replacing it with a file.
let (removals, adds) = partition (\di -> dstsha di `elem` nullShas) diff'
let mkrel di = liftIO $ relPathCwdToFile $ fromRawFilePath $
fromTopFilePath (file di) g
forM_ removals $ \di -> do
f <- mkrel di
liftIO $ nukeFile f
forM_ adds $ \di -> do
f <- mkrel di
inRepo $ Git.run [Param "checkout", Param "--", File f]
next $ liftIO cleanup