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|
{- git-annex command-line actions
-
- Copyright 2010-2015 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU GPL version 3 or higher.
-}
{-# LANGUAGE BangPatterns #-}
module CmdLine.Action where
import Common.Annex
import qualified Annex
import Annex.Concurrent
import Types.Command
import qualified Annex.Queue
import Messages.Internal
import Types.Messages
import Control.Concurrent.Async
import Control.Exception (throwIO)
import Data.Either
{- Runs a command, starting with the check stage, and then
- the seek stage. Finishes by running the continutation, and
- then showing a count of any failures. -}
performCommandAction :: Command -> CmdParams -> Annex () -> Annex ()
performCommandAction Command { cmdseek = seek, cmdcheck = c, cmdname = name } params cont = do
mapM_ runCheck c
Annex.changeState $ \s -> s { Annex.errcounter = 0 }
seek params
finishCommandActions
cont
showerrcount =<< Annex.getState Annex.errcounter
where
showerrcount 0 = noop
showerrcount cnt = error $ name ++ ": " ++ show cnt ++ " failed"
{- Runs one of the actions needed to perform a command.
- Individual actions can fail without stopping the whole command,
- including by throwing IO errors (but other errors terminate the whole
- command).
-
- When concurrency is enabled, a thread is forked off to run the action
- in the background, as soon as a free slot is available.
- This should only be run in the seek stage.
-}
commandAction :: CommandStart -> Annex ()
commandAction a = withOutputType go
where
go (ParallelOutput n) = do
ws <- Annex.getState Annex.workers
(st, ws') <- if null ws
then do
st <- dupState
return (st, replicate (n-1) (Left st))
else do
l <- liftIO $ drainTo (n-1) ws
findFreeSlot l
w <- liftIO $ async $ snd <$> Annex.run st run
Annex.changeState $ \s -> s { Annex.workers = Right w:ws' }
go _ = run
run = void $ includeCommandAction a
{- Waits for any forked off command actions to finish.
-
- Merge together the cleanup actions of all the AnnexStates used by
- threads, into the current Annex's state, so they'll run at shutdown.
-
- Also merge together the errcounters of the AnnexStates.
-}
finishCommandActions :: Annex ()
finishCommandActions = do
l <- liftIO . drainTo 0 =<< Annex.getState Annex.workers
forM_ (lefts l) mergeState
{- Wait for Asyncs from the list to finish, replacing them with their
- final AnnexStates, until the list of remaining Asyncs is not larger
- than the specified size, then returns the new list.
-
- If the action throws an exception, it is propigated, but first
- all other actions are waited for, to allow for a clean shutdown.
-}
drainTo
:: Int
-> [Either Annex.AnnexState (Async Annex.AnnexState)]
-> IO [Either Annex.AnnexState (Async Annex.AnnexState)]
drainTo sz l
| null as || sz >= length as = return l
| otherwise = do
(done, ret) <- waitAnyCatch as
let as' = filter (/= done) as
case ret of
Left e -> do
void $ drainTo 0 (map Left sts ++ map Right as')
throwIO e
Right st -> do
drainTo sz $ map Left (st:sts) ++ map Right as'
where
(sts, as) = partitionEithers l
findFreeSlot :: [Either Annex.AnnexState (Async Annex.AnnexState)] -> Annex (Annex.AnnexState, [Either Annex.AnnexState (Async Annex.AnnexState)])
findFreeSlot = go []
where
go c [] = do
st <- dupState
return (st, c)
go c (Left st:rest) = return (st, c ++ rest)
go c (v:rest) = go (v:c) rest
{- Like commandAction, but without the concurrency. -}
includeCommandAction :: CommandStart -> CommandCleanup
includeCommandAction a = account =<< tryIO go
where
go = do
Annex.Queue.flushWhenFull
callCommandAction a
account (Right True) = return True
account (Right False) = incerr
account (Left err) = do
showErr err
showEndFail
incerr
incerr = do
Annex.changeState $ \s ->
let ! c = Annex.errcounter s + 1
! s' = s { Annex.errcounter = c }
in s'
return False
{- Runs a single command action through the start, perform and cleanup
- stages, without catching errors. Useful if one command wants to run
- part of another command. -}
callCommandAction :: CommandStart -> CommandCleanup
callCommandAction = 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
|
