1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
|
{- git-annex assistant pending transfer queue
-
- Copyright 2012 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Assistant.TransferQueue (
TransferQueue,
Schedule(..),
newTransferQueue,
getTransferQueue,
queueTransfers,
queueTransfer,
queueTransferAt,
getNextTransfer
) where
import Common.Annex
import Assistant.DaemonStatus
import Logs.Transfer
import Types.Remote
import qualified Remote
import Control.Concurrent.STM
{- The transfer queue consists of a channel listing the transfers to make;
- the size of the queue is also tracked, and a list is maintained
- in parallel to allow for reading. -}
data TransferQueue = TransferQueue
{ queue :: TChan (Transfer, TransferInfo)
, queuesize :: TVar Integer
, queuelist :: TVar [(Transfer, TransferInfo)]
}
data Schedule = Next | Later
deriving (Eq)
newTransferQueue :: IO TransferQueue
newTransferQueue = atomically $ TransferQueue
<$> newTChan
<*> newTVar 0
<*> newTVar []
{- Reads the queue's content without blocking or changing it. -}
getTransferQueue :: TransferQueue -> IO [(Transfer, TransferInfo)]
getTransferQueue q = atomically $ readTVar $ queuelist q
stubInfo :: AssociatedFile -> Remote -> TransferInfo
stubInfo f r = TransferInfo
{ startedTime = Nothing
, transferPid = Nothing
, transferTid = Nothing
, transferRemote = Just r
, bytesComplete = Nothing
, associatedFile = f
}
{- Adds transfers to queue for some of the known remotes. -}
queueTransfers :: Schedule -> TransferQueue -> DaemonStatusHandle -> Key -> AssociatedFile -> Direction -> Annex ()
queueTransfers schedule q daemonstatus k f direction = do
rs <- knownRemotes <$> getDaemonStatus daemonstatus
mapM_ go =<< sufficientremotes rs
where
sufficientremotes rs
-- Queue downloads from all remotes that
-- have the key, with the cheapest ones first.
-- More expensive ones will only be tried if
-- downloading from a cheap one fails.
| direction == Download = do
uuids <- Remote.keyLocations k
return $ filter (\r -> uuid r `elem` uuids) rs
-- TODO: Determine a smaller set of remotes that
-- can be uploaded to, in order to ensure all
-- remotes can access the content. Currently,
-- send to every remote we can.
| otherwise = return rs
gentransfer r = Transfer
{ transferDirection = direction
, transferKey = k
, transferUUID = Remote.uuid r
}
go r = liftIO $ atomically $
enqueue schedule q (gentransfer r) (stubInfo f r)
enqueue :: Schedule -> TransferQueue -> Transfer -> TransferInfo -> STM ()
enqueue schedule q t info
| schedule == Next = go unGetTChan (new:)
| otherwise = go writeTChan (\l -> l++[new])
where
new = (t, info)
go modqueue modlist = do
void $ modqueue (queue q) new
void $ modifyTVar' (queuesize q) succ
void $ modifyTVar' (queuelist q) modlist
{- Adds a transfer to the queue. -}
queueTransfer :: Schedule -> TransferQueue -> AssociatedFile -> Transfer -> Remote -> IO ()
queueTransfer schedule q f t remote = atomically $
enqueue schedule q t (stubInfo f remote)
{- Blocks until the queue is no larger than a given size, and then adds a
- transfer to the queue. -}
queueTransferAt :: Integer -> Schedule -> TransferQueue -> AssociatedFile -> Transfer -> Remote -> IO ()
queueTransferAt wantsz schedule q f t remote = atomically $ do
sz <- readTVar (queuesize q)
if sz <= wantsz
then enqueue schedule q t (stubInfo f remote)
else retry -- blocks until queuesize changes
{- Blocks until a pending transfer is available from the queue. -}
getNextTransfer :: TransferQueue -> IO (Transfer, TransferInfo)
getNextTransfer q = atomically $ do
void $ modifyTVar' (queuesize q) pred
void $ modifyTVar' (queuelist q) (drop 1)
readTChan (queue q)
|