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|
{- git-annex command-line actions
-
- Copyright 2010-2017 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU GPL version 3 or higher.
-}
{-# LANGUAGE CPP #-}
module CmdLine.Action where
import Annex.Common
import qualified Annex
import Annex.Concurrent
import Types.Command
import Types.Concurrency
import Messages.Concurrent
import Types.Messages
import Remote.List
import Control.Concurrent
import Control.Concurrent.Async
import Control.Concurrent.STM
import Control.Exception (throwIO)
import Data.Either
import qualified Data.Map.Strict as M
#ifdef WITH_CONCURRENTOUTPUT
import qualified System.Console.Regions as Regions
#endif
{- 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 -> CommandSeek -> Annex () -> Annex ()
performCommandAction Command { cmdcheck = c, cmdname = name } seek cont = do
mapM_ runCheck c
Annex.changeState $ \s -> s { Annex.errcounter = 0 }
seek
finishCommandActions
cont
showerrcount =<< Annex.getState Annex.errcounter
where
showerrcount 0 = noop
showerrcount cnt = giveup $ 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 = go =<< Annex.getState Annex.concurrency
where
go (Concurrent n) = do
ws <- Annex.getState Annex.workers
(st, ws') <- if null ws
then do
-- Generate the remote list now, to avoid
-- each thread generating it, which would
-- be more expensive and could cause
-- threads to contend over eg, calls to
-- setConfig.
_ <- remoteList
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 (inOwnConsoleRegion (Annex.output st) run)
Annex.changeState $ \s -> s { Annex.workers = Right w:ws' }
go NonConcurrent = 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
ws <- Annex.getState Annex.workers
Annex.changeState $ \s -> s { Annex.workers = [] }
l <- liftIO $ drainTo 0 ws
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 (callCommandAction a)
where
account (Right True) = return True
account (Right False) = incerr
account (Left err) = do
toplevelWarning True (show err)
implicitMessage showEndFail
incerr
incerr = do
Annex.incError
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 = fromMaybe True <$$> callCommandAction'
{- Like callCommandAction, but returns Nothing when the command did not
- perform any action. -}
callCommandAction' :: CommandStart -> Annex (Maybe Bool)
callCommandAction' a = callCommandActionQuiet a >>= \case
Nothing -> return Nothing
Just r -> implicitMessage (showEndResult r) >> return (Just r)
callCommandActionQuiet :: CommandStart -> Annex (Maybe Bool)
callCommandActionQuiet = start
where
start = stage $ maybe skip perform
perform = stage $ maybe failure cleanup
cleanup = stage $ status
stage = (=<<)
skip = return Nothing
failure = return (Just False)
status = return . Just
{- Do concurrent output when that has been requested. -}
allowConcurrentOutput :: Annex a -> Annex a
#ifdef WITH_CONCURRENTOUTPUT
allowConcurrentOutput a = go =<< Annex.getState Annex.concurrency
where
go NonConcurrent = a
go (Concurrent _) = ifM (liftIO concurrentOutputSupported)
( Regions.displayConsoleRegions $
goconcurrent True
, goconcurrent False
)
goconcurrent b = bracket_ (setup b) cleanup a
setup = setconcurrentenabled
cleanup = do
finishCommandActions
setconcurrentenabled False
setconcurrentenabled b = Annex.changeState $ \s ->
s { Annex.output = (Annex.output s) { concurrentOutputEnabled = b } }
#else
allowConcurrentOutput = id
#endif
{- Ensures that only one thread processes a key at a time.
- Other threads will block until it's done. -}
onlyActionOn :: Key -> CommandStart -> CommandStart
onlyActionOn k a = onlyActionOn' k run
where
-- Run whole action, not just start stage, so other threads
-- block until it's done.
run = callCommandActionQuiet a >>= \case
Nothing -> return Nothing
Just r' -> return $ Just $ return $ Just $ return r'
onlyActionOn' :: Key -> Annex a -> Annex a
onlyActionOn' k a = go =<< Annex.getState Annex.concurrency
where
go NonConcurrent = a
go (Concurrent _) = do
tv <- Annex.getState Annex.activekeys
bracket (setup tv) id (const a)
setup tv = liftIO $ do
mytid <- myThreadId
atomically $ do
m <- readTVar tv
case M.lookup k m of
Just tid
| tid /= mytid -> retry
| otherwise -> return (return ())
Nothing -> do
writeTVar tv $! M.insert k mytid m
return $ liftIO $ atomically $
modifyTVar tv $ M.delete k
|
