40ecf58d4b
This does not change the overall license of the git-annex program, which was already AGPL due to a number of sources files being AGPL already. Legally speaking, I'm adding a new license under which these files are now available; I already released their current contents under the GPL license. Now they're dual licensed GPL and AGPL. However, I intend for all my future changes to these files to only be released under the AGPL license, and I won't be tracking the dual licensing status, so I'm simply changing the license statement to say it's AGPL. (In some cases, others wrote parts of the code of a file and released it under the GPL; but in all cases I have contributed a significant portion of the code in each file and it's that code that is getting the AGPL license; the GPL license of other contributors allows combining with AGPL code.)
64 lines
1.8 KiB
Haskell
64 lines
1.8 KiB
Haskell
{- git-annex concurrent state
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-
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- Copyright 2015 Joey Hess <id@joeyh.name>
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-
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- Licensed under the GNU AGPL version 3 or higher.
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-}
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module Annex.Concurrent where
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import Annex
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import Annex.Common
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import Annex.Action
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import qualified Annex.Queue
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import qualified Data.Map as M
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{- Allows forking off a thread that uses a copy of the current AnnexState
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- to run an Annex action.
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-
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- The returned IO action can be used to start the thread.
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- It returns an Annex action that must be run in the original
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- calling context to merge the forked AnnexState back into the
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- current AnnexState.
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-}
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forkState :: Annex a -> Annex (IO (Annex a))
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forkState a = do
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st <- dupState
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return $ do
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(ret, newst) <- run st a
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return $ do
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mergeState newst
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return ret
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{- Returns a copy of the current AnnexState that is safe to be
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- used when forking off a thread.
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-
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- After an Annex action is run using this AnnexState, it
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- should be merged back into the current Annex's state,
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- by calling mergeState.
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-}
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dupState :: Annex AnnexState
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dupState = do
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st <- Annex.getState id
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return $ st
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{ Annex.workers = []
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-- each thread has its own repoqueue, but the repoqueuesem
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-- is shared to prevent more than one thread flushing its
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-- queue at the same time
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, Annex.repoqueue = Nothing
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-- avoid sharing eg, open file handles
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, Annex.catfilehandles = M.empty
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, Annex.checkattrhandle = Nothing
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, Annex.checkignorehandle = Nothing
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}
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{- Merges the passed AnnexState into the current Annex state.
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- Also closes various handles in it. -}
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mergeState :: AnnexState -> Annex ()
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mergeState st = do
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st' <- liftIO $ snd <$> run st stopCoProcesses
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forM_ (M.toList $ Annex.cleanup st') $
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uncurry addCleanup
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Annex.Queue.mergeFrom st'
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changeState $ \s -> s { errcounter = errcounter s + errcounter st' }
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