ca2e5b3 · distributed-process

git.iko.soy/distributed-process

Introduce callLocal primitive.

'callLocal' provides a way to create processes that are isolated by their ProcessId, so one can send messages to that processes iff that process announced his id, and all messages that were sent to that process after it dies will be silently discarded.

commitca2e5b3ecd2e850081303fac52d48111fdd4131c authorAlexander Vershilov <alexander.vershilov@tweag.io> dateSun 11 Jan 2015, 22:42 (12 years ago) parent87309ac

1 file changed+19

compare with master

unifiedsplit

src/Control/Distributed/Process.hs+19

src/Control/Distributed/Process.hs+19

@@ -149,6 +149,7 @@ module Control.Distributed.Process

149149 -- * Local versions of 'spawn'

150150 , spawnLocal

151151 , spawnChannelLocal

152+ , callLocal

152153 -- * Reconnecting

153154 , reconnect

154155 , reconnectPort

@@ -302,6 +303,7 @@ import Control.Distributed.Process.Internal.Spawn

302303 , spawnSupervised

303304 , call

304305 )

306+import Control.Exception (SomeException, throwIO)

305307

306308-- INTERNAL NOTES

307309--

@@ -392,3 +394,20 @@ spawnChannelLocal proc = do

392394 liftIO $ putMVar mvar sport

393395 proc rport

394396 takeMVar mvar

397+

398+-- | Local version of 'call'. Running a process in this way isolates it from

399+-- messages sent to the caller process, and also allows silently dropping late

400+-- or duplicate messages sent to the isolated process after it exits.

401+-- Silently dropping messages may not always be the best approach.

402+callLocal ::

403+ Process a -- ^ Process to run

404+ -> Process a -- ^ Value returned

405+callLocal proc = do

406+ mv <- liftIO newEmptyMVar

407+ self <- getSelfPid

408+ _ <- spawnLocal $ do

409+ link self

410+ try proc >>= liftIO . putMVar mv

411+ liftIO $ takeMVar mv >>=

412+ either (throwIO :: SomeException -> IO a) return

413+