2b97428 · typeable/wai

git.iko.soy/typeable/wai

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Guarantee atomicity of WINDOW_UPDATE increments.

2b97428Lucas DiCioccio9 years ago

warp/Network/Wai/Handler/Warp/HTTP2/Receiver.hs+10−4

compare with master

unifiedsplit

@@ -232,9 +232,12 @@ control FrameGoAway _ _ Context{controlQ} = do

232

233control FrameWindowUpdate header bs Context{connectionWindow} = do

234 WindowUpdateFrame n <- guardIt $ decodeWindowUpdateFrame header bs

235+ !w <- atomically $ do

235− !w <- (n +) <$> atomically (readTVar connectionWindow)

236+ w0 <- readTVar connectionWindow

237+ let w1 = w0 + n

238+ writeTVar connectionWindow w1

239+ return w1

236 when (isWindowOverflow w) $ E.throwIO $ ConnectionError FlowControlError "control window should be less than 2^31"

240 when (isWindowOverflow w) $ E.throwIO $ ConnectionError FlowControlError "control window should be less than 2^31"

237− atomically $ writeTVar connectionWindow w

238 return True

241 return True

239

242

240control _ _ _ _ =

243control _ _ _ _ =

@@ -336,10 +339,13 @@ stream FrameContinuation FrameHeader{flags} frag ctx (Open (Continued rfrags siz

336

339

337stream FrameWindowUpdate header@FrameHeader{streamId} bs _ s Stream{streamWindow} = do

340stream FrameWindowUpdate header@FrameHeader{streamId} bs _ s Stream{streamWindow} = do

338 WindowUpdateFrame n <- guardIt $ decodeWindowUpdateFrame header bs

341 WindowUpdateFrame n <- guardIt $ decodeWindowUpdateFrame header bs

342+ !w <- atomically $ do

339− !w <- (n +) <$> atomically (readTVar streamWindow)

343+ w0 <- readTVar streamWindow

344+ let w1 = w0 + n

345+ writeTVar streamWindow w1

346+ return w1

340 when (isWindowOverflow w) $

347 when (isWindowOverflow w) $

341 E.throwIO $ StreamError FlowControlError streamId

348 E.throwIO $ StreamError FlowControlError streamId

342− atomically $ writeTVar streamWindow w

343 return s

349 return s

344

350

345stream FrameRSTStream header bs ctx _ strm = do

351stream FrameRSTStream header bs ctx _ strm = do