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
|
{-# LANGUAGE BangPatterns #-}
{-# LANGUAGE NamedFieldPuns #-}
module Network.HTTP2.H2.Window where
import Control.Concurrent.STM
import qualified Control.Exception as E
import qualified Data.ByteString as BS
import Data.IORef
import Network.Control
import Imports
import Network.HTTP2.Frame
import Network.HTTP2.H2.Context
import Network.HTTP2.H2.EncodeFrame
import Network.HTTP2.H2.Queue
import Network.HTTP2.H2.Types
getStreamWindowSize :: Stream -> IO WindowSize
getStreamWindowSize Stream{streamTxFlow} =
txWindowSize <$> readTVarIO streamTxFlow
getConnectionWindowSize :: Context -> IO WindowSize
getConnectionWindowSize Context{txFlow} =
txWindowSize <$> readTVarIO txFlow
waitStreamWindowSize :: Stream -> IO ()
waitStreamWindowSize Stream{streamTxFlow} = atomically $ do
w <- txWindowSize <$> readTVar streamTxFlow
check (w > 0)
waitConnectionWindowSize :: Context -> STM ()
waitConnectionWindowSize Context{txFlow} = do
w <- txWindowSize <$> readTVar txFlow
check (w > 0)
----------------------------------------------------------------
-- Receiving window update
increaseWindowSize :: StreamId -> TVar TxFlow -> WindowSize -> IO ()
increaseWindowSize sid tvar n = do
atomically $ modifyTVar' tvar $ \flow -> flow{txfLimit = txfLimit flow + n}
w <- txWindowSize <$> readTVarIO tvar
when (isWindowOverflow w) $ do
let msg = fromString ("window update for stream " ++ show sid ++ " is overflow")
err =
if isControl sid
then ConnectionErrorIsSent
else StreamErrorIsSent
E.throwIO $ err FlowControlError sid msg
increaseStreamWindowSize :: Stream -> WindowSize -> IO ()
increaseStreamWindowSize Stream{streamNumber, streamTxFlow} n =
increaseWindowSize streamNumber streamTxFlow n
increaseConnectionWindowSize :: Context -> Int -> IO ()
increaseConnectionWindowSize Context{txFlow} n =
increaseWindowSize 0 txFlow n
decreaseWindowSize :: Context -> Stream -> WindowSize -> IO ()
decreaseWindowSize Context{txFlow} Stream{streamTxFlow} siz = do
dec txFlow
dec streamTxFlow
where
dec tvar = atomically $ modifyTVar' tvar $ \flow -> flow{txfSent = txfSent flow + siz}
----------------------------------------------------------------
-- Sending window update
informWindowUpdate :: Context -> Stream -> Int -> IO ()
informWindowUpdate _ _ 0 = return ()
informWindowUpdate Context{controlQ, rxFlow} Stream{streamNumber, streamRxFlow} len = do
mxc <- atomicModifyIORef rxFlow $ maybeOpenRxWindow len FCTWindowUpdate
forM_ mxc $ \ws -> do
let frame = windowUpdateFrame 0 ws
cframe = CFrames Nothing [frame]
enqueueControl controlQ cframe
mxs <- atomicModifyIORef streamRxFlow $ maybeOpenRxWindow len FCTWindowUpdate
forM_ mxs $ \ws -> do
let frame = windowUpdateFrame streamNumber ws
cframe = CFrames Nothing [frame]
enqueueControl controlQ cframe
-- This must be called after an application is finished
-- to adjust RX window.
adjustRxWindow :: Context -> Stream -> IO ()
adjustRxWindow ctx stream@Stream{streamRxQ} = do
mq <- readIORef streamRxQ
case mq of
Nothing -> return ()
Just q -> do
len <- readQ q
informWindowUpdate ctx stream len
where
readQ q = atomically $ loop 0
where
loop !total = do
meb <- tryReadTQueue q
case meb of
Just (Right (bs, _)) -> loop (total + BS.length bs)
Just le@(Left _) -> do
-- reserving HTTP2Error
writeTQueue q le
return total
_ -> return total
|
