diff options
| author |  Joey Hess <joey@kitenet.net> | 2012-06-26 17:33:34 -0400 |
|---|---|---|
| committer | Joey Hess <joey@kitenet.net> | 2012-06-26 19:21:44 -0400 |
| commit | 67c8ef7de25ad6f433db2fa5d5fc764dd515a5b2 (patch) | |
| tree | 3666619b0752df6c336fdbac270e09dbd125bcec /Utility/Parallel.hs | |
| parent | e0a65247aebb8a821f4f0b717d39a4a35136a2e6 (diff) | |
use a TMVar
SampleMVar won't work; between getting the current value and changing
it, another thread could made a change, which would get lost.
TMVar works well; this update situation is handled by atomic transactions.
Diffstat (limited to 'Utility/Parallel.hs')
| -rw-r--r-- | Utility/Parallel.hs | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/Utility/Parallel.hs b/Utility/Parallel.hs index 6e4671c05..9df95ab2b 100644 --- a/Utility/Parallel.hs +++ b/Utility/Parallel.hs @@ -10,11 +10,13 @@ module Utility.Parallel where import Common {- Runs an action in parallel with a set of values. - - Returns values that caused the action to fail. -} -inParallel :: (v -> IO ()) -> [v] -> IO [v] + - Returns the values partitioned into ones with which the action succeeded, + - and ones with which it failed. -} +inParallel :: (v -> IO ()) -> [v] -> IO ([v], [v]) inParallel a l = do pids <- mapM (forkProcess . a) l statuses <- mapM (getProcessStatus True False) pids - return $ map fst $ filter (failed . snd) $ zip l statuses + return $ reduce $ partition (succeeded . snd) $ zip l statuses where - failed v = v /= Just (Exited ExitSuccess) + succeeded v = v == Just (Exited ExitSuccess) + reduce (x,y) = (map fst x, map fst y) |