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
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
|
{- 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
import qualified Data.Map as M
{- 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 dstatus k f direction = do
rs <- knownRemotes <$> liftIO (getDaemonStatus dstatus)
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 $
enqueue schedule q dstatus (gentransfer r) (stubInfo f r)
enqueue :: Schedule -> TransferQueue -> DaemonStatusHandle -> Transfer -> TransferInfo -> IO ()
enqueue schedule q dstatus t info
| schedule == Next = go unGetTChan (new:)
| otherwise = go writeTChan (\l -> l++[new])
where
new = (t, info)
go modqueue modlist = do
atomically $ do
void $ modqueue (queue q) new
void $ modifyTVar' (queuesize q) succ
void $ modifyTVar' (queuelist q) modlist
void $ notifyTransfer dstatus
{- Adds a transfer to the queue. -}
queueTransfer :: Schedule -> TransferQueue -> DaemonStatusHandle -> AssociatedFile -> Transfer -> Remote -> IO ()
queueTransfer schedule q dstatus f t remote =
enqueue schedule q dstatus 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 -> DaemonStatusHandle -> AssociatedFile -> Transfer -> Remote -> IO ()
queueTransferAt wantsz schedule q dstatus f t remote = do
atomically $ do
sz <- readTVar (queuesize q)
if sz <= wantsz
then return ()
else retry -- blocks until queuesize changes
enqueue schedule q dstatus t (stubInfo f remote)
{- Blocks until a pending transfer is available from the queue,
- and removes it.
-
- Checks that it's acceptable, before adding it to the
- the currentTransfers map. If it's not acceptable, it's discarded.
-
- This is done in a single STM transaction, so there is no window
- where an observer sees an inconsistent status. -}
getNextTransfer :: TransferQueue -> DaemonStatusHandle -> (TransferInfo -> Bool) -> IO (Maybe (Transfer, TransferInfo))
getNextTransfer q dstatus acceptable = atomically $ do
void $ modifyTVar' (queuesize q) pred
void $ modifyTVar' (queuelist q) (drop 1)
r@(t, info) <- readTChan (queue q)
if acceptable info
then do
adjustTransfersSTM dstatus $
M.insertWith' const t info
return $ Just r
else return Nothing
|
