git-annex/GitQueue.hs
2011-04-01 12:19:26 -04:00

68 lines
1.8 KiB
Haskell

{- git repository command queue
-
- Copyright 2010 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module GitQueue (
Queue,
empty,
add,
size,
run
) where
import qualified Data.Map as M
import System.IO
import System.Cmd.Utils
import Data.String.Utils
import Control.Monad (unless, forM_)
import Utility
import qualified GitRepo as Git
{- An action to perform in a git repository. The file to act on
- is not included, and must be able to be appended after the params. -}
data Action = Action {
getSubcommand :: String,
getParams :: [CommandParam]
} deriving (Show, Eq, Ord)
{- A queue of actions to perform (in any order) on a git repository,
- with lists of files to perform them on. This allows coalescing
- similar git commands. -}
data Queue = Queue Integer (M.Map Action [FilePath])
deriving (Show, Eq)
{- Constructor for empty queue. -}
empty :: Queue
empty = Queue 0 M.empty
{- Adds an action to a queue. -}
add :: Queue -> String -> [CommandParam] -> FilePath -> Queue
add (Queue n m) subcommand params file = Queue (n + 1) m'
where
action = Action subcommand params
m' = M.insertWith' (++) action [file] m
{- Number of items in a queue. -}
size :: Queue -> Integer
size (Queue n _) = n
{- Runs a queue on a git repository. -}
run :: Git.Repo -> Queue -> IO ()
run repo (Queue _ m) = do
forM_ (M.toList m) $ uncurry $ runAction repo
return ()
{- Runs an Action on a list of files in a git repository.
-
- Complicated by commandline length limits. -}
runAction :: Git.Repo -> Action -> [FilePath] -> IO ()
runAction repo action files = unless (null files) runxargs
where
runxargs = pOpen WriteToPipe "xargs" ("-0":"git":params) feedxargs
params = toCommand $ Git.gitCommandLine repo
(Param (getSubcommand action):getParams action)
feedxargs h = hPutStr h $ join "\0" files