41 lines
1 KiB
Haskell
41 lines
1 KiB
Haskell
{- git-annex assistant transfer slots
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-
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- Copyright 2012 Joey Hess <joey@kitenet.net>
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-
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- Licensed under the GNU GPL version 3 or higher.
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-}
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module Assistant.TransferSlots where
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import Control.Exception
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import Control.Concurrent
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import Common.Annex
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import Assistant.ThreadedMonad
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type TransferSlots = QSemN
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{- Number of concurrent transfers allowed to be run from the assistant.
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-
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- Transfers launched by other means, including by remote assistants,
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- do not currently take up slots.
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-}
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numSlots :: Int
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numSlots = 1
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newTransferSlots :: IO TransferSlots
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newTransferSlots = newQSemN numSlots
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{- Waits until a transfer slot becomes available, and runs a transfer
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- action in the slot, in its own thread. -}
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inTransferSlot :: TransferSlots -> ThreadState -> Annex a -> IO ThreadId
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inTransferSlot s st a = do
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waitQSemN s 1
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forkIO $ bracket_ noop done run
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where
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done = transferComplete s
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run = unsafeRunThreadState st a
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{- Call when a transfer is complete. -}
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transferComplete :: TransferSlots -> IO ()
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transferComplete s = signalQSemN s 1
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