git-annex/Annex/Queue.hs

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{- git-annex command queue
-
- Copyright 2011, 2012 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
{-# LANGUAGE BangPatterns #-}
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module Annex.Queue (
addCommand,
addInternalAction,
addUpdateIndex,
flush,
flushWhenFull,
size,
get,
mergeFrom,
) where
import Annex.Common
import Annex hiding (new)
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import qualified Git.Queue
import qualified Git.UpdateIndex
import qualified Control.Concurrent.SSem as SSem
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{- Adds a git command to the queue. -}
addCommand :: String -> [CommandParam] -> [FilePath] -> Annex ()
addCommand command params files = do
q <- get
store <=< flushWhenFull <=< inRepo $
Git.Queue.addCommand command params files q
addInternalAction :: Git.Queue.InternalActionRunner -> [(FilePath, IO Bool)] -> Annex ()
addInternalAction runner files = do
q <- get
store <=< flushWhenFull <=< inRepo $
Git.Queue.addInternalAction runner files q
{- Adds an update-index stream to the queue. -}
addUpdateIndex :: Git.UpdateIndex.Streamer -> Annex ()
addUpdateIndex streamer = do
q <- get
store <=< flushWhenFull <=< inRepo $
Git.Queue.addUpdateIndex streamer q
{- Runs the queue if it is full. -}
flushWhenFull :: Git.Queue.Queue -> Annex Git.Queue.Queue
flushWhenFull q
| Git.Queue.full q = flush' q
| otherwise = return q
{- Runs (and empties) the queue. -}
flush :: Annex ()
flush = do
q <- get
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unless (0 == Git.Queue.size q) $ do
store =<< flush' q
{- When there are multiple worker threads, each has its own queue.
-
- But, flushing two queues at the same time could lead to failures due to
- git locking files. So, only one queue is allowed to flush at a time.
- The repoqueuesem is shared between threads.
-}
flush' :: Git.Queue.Queue -> Annex Git.Queue.Queue
flush' q = bracket lock unlock go
where
lock = do
s <- getState repoqueuesem
liftIO $ SSem.wait s
return s
unlock = liftIO . SSem.signal
go _ = do
showStoringStateAction
inRepo $ Git.Queue.flush q
{- Gets the size of the queue. -}
size :: Annex Int
size = Git.Queue.size <$> get
get :: Annex Git.Queue.Queue
get = maybe new return =<< getState repoqueue
new :: Annex Git.Queue.Queue
new = do
q <- Git.Queue.new . annexQueueSize <$> getGitConfig
store q
return q
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store :: Git.Queue.Queue -> Annex ()
store q = changeState $ \s -> s { repoqueue = Just q }
mergeFrom :: AnnexState -> Annex ()
mergeFrom st = case repoqueue st of
Nothing -> noop
Just newq -> do
q <- get
let !q' = Git.Queue.merge q newq
store =<< flushWhenFull q'