{- git-annex v5 -> v6 upgrade support
 -
 - Copyright 2015-2019 Joey Hess <id@joeyh.name>
 -
 - Licensed under the GNU AGPL version 3 or higher.
 -}

{-# LANGUAGE OverloadedStrings #-}

module Upgrade.V5 where

import Annex.Common
import Config
import Config.Smudge
import Annex.InodeSentinal
import Annex.Link
import Annex.CatFile
import Annex.WorkTree
import Annex.UUID
import Logs.Location
import qualified Upgrade.V5.Direct as Direct
import qualified Annex.Content as Content
import qualified Database.Keys
import qualified Git
import qualified Git.LsFiles
import qualified Git.Branch
import qualified Git.Version
import Git.FilePath
import Git.FileMode
import Git.Config
import Git.Ref
import Utility.InodeCache
import Utility.DottedVersion
import Annex.AdjustedBranch

import qualified Data.ByteString as S

upgrade :: Bool -> Annex Bool
upgrade automatic = flip catchNonAsync onexception $ do
	unless automatic $
		showAction "v5 to v6"
	ifM isDirect
		( do
			checkGitVersionForDirectUpgrade
			convertDirect
		, do
			checkGitVersionForIndirectUpgrade
		)
	scanUnlockedFiles
	configureSmudgeFilter
	-- Inode sentinal file was only used in direct mode and when
	-- locking down files as they were added. In v6, it's used more
	-- extensively, so make sure it exists, since old repos that didn't
	-- use direct mode may not have created it.
	unlessM isDirect $
		createInodeSentinalFile True
	return True
  where
	onexception e = do
		warning $ "caught exception: " ++ show e
		return False

-- git before 2.22 would OOM running git status on a large file.
--
-- Older versions of git that are patched (with
-- commit 02156ab031e430bc45ce6984dfc712de9962dec8)
-- can include "oomfix" in their version to indicate it.
gitWillOOM :: Annex Bool
gitWillOOM = liftIO $ do
	v <- Git.Version.installed
	return $ v < Git.Version.normalize "2.22" &&
		not ("oomfix" `isInfixOf` fromDottedVersion v)

-- configureSmudgeFilter has to run git status, and direct mode files
-- are unlocked, so avoid the upgrade failing half way through.
checkGitVersionForDirectUpgrade :: Annex ()
checkGitVersionForDirectUpgrade = whenM gitWillOOM $
	giveup "You must upgrade git to version 2.22 or newer in order to use this version of git-annex in this repository."

checkGitVersionForIndirectUpgrade :: Annex ()
checkGitVersionForIndirectUpgrade = whenM gitWillOOM $
	warning "Git is older than version 2.22 and so it has a memory leak that affects using unlocked files. Recommend you upgrade git before unlocking any files in your repository."

convertDirect :: Annex ()
convertDirect = do
	{- Direct mode makes the same tradeoff of using less disk
	 - space, with less preservation of old versions of files
	 - as does annex.thin. -}
	setConfig (annexConfig "thin") (boolConfig True)
	Direct.setIndirect
	cur <- fromMaybe (error "Somehow no branch is checked out")
		<$> inRepo Git.Branch.current
	upgradeDirectWorkTree
	removeDirectCruft
	{- Create adjusted branch where all files are unlocked.
	 - This should have the same content for each file as
	 - have been staged in upgradeDirectWorkTree. -}
	AdjBranch b <- adjustBranch (LinkAdjustment UnlockAdjustment) cur
	{- Since the work tree was already set up by
	 - upgradeDirectWorkTree, and contains unlocked file
	 - contents too, don't use git checkout to check out the
	 - adjust branch. Instead, update HEAD manually. -}
	inRepo $ setHeadRef b

{- Walk work tree from top and convert all annex symlinks to pointer files,
 - staging them in the index, and populating the annex objects with
 - hard links (or copies) of the work tree files (when not modified or
 - deleted).
 -}
upgradeDirectWorkTree :: Annex ()
upgradeDirectWorkTree = do
	top <- fromRepo Git.repoPath
	(l, clean) <- inRepo $ Git.LsFiles.stagedDetails [top]
	forM_ l go
	void $ liftIO clean
  where
	go (f, _sha, mode, _stagenum) | isSymLink mode = do
		-- Cannot use lookupFile here, as we're in between direct
		-- mode and v6.
		mk <- catKeyFile f
		case mk of
			Nothing -> noop
			Just k -> do
				stagePointerFile f Nothing =<< hashPointerFile k
				ifM (isJust <$> getAnnexLinkTarget f)
					( writepointer (fromRawFilePath f) k
					, fromdirect (fromRawFilePath f) k
					)
				Database.Keys.addAssociatedFile k
					=<< inRepo (toTopFilePath f)
	go _ = noop

	fromdirect f k = ifM (Direct.goodContent k f)
		( do
			-- If linkToAnnex fails for some reason, the work tree
			-- file still has the content; the annex object file
			-- is just not populated with it. Since the work tree
			-- file is recorded as an associated file, things will
			-- still work that way, it's just not ideal.
			ic <- withTSDelta (liftIO . genInodeCache (toRawFilePath f))
			void $ Content.linkToAnnex k f ic
		, unlessM (Content.inAnnex k) $ do
			-- Worktree file was deleted or modified;
			-- if there are no other copies of the content
			-- then it's been lost.
			locs <- Direct.associatedFiles k
			unlessM (anyM (Direct.goodContent k) locs) $ do
				u <- getUUID
				logChange k u InfoMissing
		)
	
	writepointer f k = liftIO $ do
		nukeFile f
		S.writeFile f (formatPointer k)

{- Remove all direct mode bookkeeping files. -}
removeDirectCruft :: Annex ()
removeDirectCruft = mapM_ go =<< Content.listKeys Content.InAnywhere
  where
	go k = do
		Direct.removeInodeCache k
		Direct.removeAssociatedFiles k