git-annex/Command.hs
Joey Hess cbaebf538a rework git check-attr interface
Now gitattributes are looked up, efficiently, in only the places that
really need them, using the same approach used for cat-file.

The old CheckAttr code seemed very fragile, in the way it streamed files
through git check-attr.
I actually found that cad8824852
was still deadlocking with ghc 7.4, at the end of adding a lot of files.
This should fix that problem, and avoid future ones.

The best part is that this removes withAttrFilesInGit and withNumCopies,
which were complicated Seek methods, as well as simplfying the types
for several other Seek methods that had a Backend tupled in.
2012-02-13 23:52:21 -04:00

121 lines
3.5 KiB
Haskell

{- git-annex command infrastructure
-
- Copyright 2010-2011 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Command (
command,
noRepo,
withOptions,
next,
stop,
stopUnless,
prepCommand,
doCommand,
whenAnnexed,
ifAnnexed,
notBareRepo,
isBareRepo,
numCopies,
autoCopies,
module ReExported
) where
import Common.Annex
import qualified Backend
import qualified Annex
import qualified Git
import qualified Remote
import Types.Command as ReExported
import Types.Option as ReExported
import Seek as ReExported
import Checks as ReExported
import Usage as ReExported
import Logs.Trust
import Config
import Annex.CheckAttr
{- Generates a normal command -}
command :: String -> String -> [CommandSeek] -> String -> Command
command = Command [] Nothing commonChecks
{- Adds a fallback action to a command, that will be run if it's used
- outside a git repository. -}
noRepo :: IO () -> Command -> Command
noRepo a c = c { cmdnorepo = Just a }
{- Adds options to a command. -}
withOptions :: [Option] -> Command -> Command
withOptions o c = c { cmdoptions = o }
{- For start and perform stages to indicate what step to run next. -}
next :: a -> Annex (Maybe a)
next a = return $ Just a
{- Or to indicate nothing needs to be done. -}
stop :: Annex (Maybe a)
stop = return Nothing
{- Stops unless a condition is met. -}
stopUnless :: Annex Bool -> Annex (Maybe a) -> Annex (Maybe a)
stopUnless c a = do
ok <- c
if ok then a else stop
{- Prepares to run a command via the check and seek stages, returning a
- list of actions to perform to run the command. -}
prepCommand :: Command -> [String] -> Annex [CommandCleanup]
prepCommand Command { cmdseek = seek, cmdcheck = c } params = do
mapM_ runCheck c
map doCommand . concat <$> mapM (\s -> s params) seek
{- Runs a command through the start, perform and cleanup stages -}
doCommand :: CommandStart -> CommandCleanup
doCommand = start
where
start = stage $ maybe skip perform
perform = stage $ maybe failure cleanup
cleanup = stage $ status
stage = (=<<)
skip = return True
failure = showEndFail >> return False
status r = showEndResult r >> return r
{- Modifies an action to only act on files that are already annexed,
- and passes the key and backend on to it. -}
whenAnnexed :: (FilePath -> (Key, Backend) -> Annex (Maybe a)) -> FilePath -> Annex (Maybe a)
whenAnnexed a file = ifAnnexed file (a file) (return Nothing)
ifAnnexed :: FilePath -> ((Key, Backend) -> Annex a) -> Annex a -> Annex a
ifAnnexed file yes no = maybe no yes =<< Backend.lookupFile file
notBareRepo :: Annex a -> Annex a
notBareRepo a = do
whenM isBareRepo $
error "You cannot run this subcommand in a bare repository."
a
isBareRepo :: Annex Bool
isBareRepo = fromRepo Git.repoIsLocalBare
numCopies :: FilePath -> Annex (Maybe Int)
numCopies file = readish <$> checkAttr "annex.numcopies" file
{- Used for commands that have an auto mode that checks the number of known
- copies of a key.
-
- In auto mode, first checks that the number of known
- copies of the key is > or < than the numcopies setting, before running
- the action. -}
autoCopies :: FilePath -> Key -> (Int -> Int -> Bool) -> (Maybe Int -> CommandStart) -> CommandStart
autoCopies file key vs a = do
numcopiesattr <- numCopies file
Annex.getState Annex.auto >>= auto numcopiesattr
where
auto numcopiesattr False = a numcopiesattr
auto numcopiesattr True = do
needed <- getNumCopies numcopiesattr
(_, have) <- trustPartition UnTrusted =<< Remote.keyLocations key
if length have `vs` needed then a numcopiesattr else stop