60fbb46 · typeable/wai

34 , defaultUpdateSettings

35 -- * Accessors

36 , updateAction

37− , updateActionModify

38 , updateFreq

37 , updateFreq

39 , updateSpawnThreshold

38 , updateSpawnThreshold

40 -- * Creation

39 -- * Creation

41 , mkAutoUpdate

40 , mkAutoUpdate

41+ , mkAutoUpdateWithModify

42 ) where

43

44#if __GLASGOW_HASKELL__ < 709

60 { updateFreq = 1000000

61 , updateSpawnThreshold = 3

62 , updateAction = return ()

63− , updateActionModify = Nothing

64 }

63 }

65

64

66-- | Settings to control how values are updated.

65-- | Settings to control how values are updated.

97 -- Default: does nothing.

96 -- Default: does nothing.

98 --

97 --

99 -- @since 0.1.0

98 -- @since 0.1.0

100− , updateActionModify :: Maybe (a -> IO a)

101− -- ^ Optional action to be performed to get the current value

102− -- and update it if necessary.

103− --

104− -- Default: does nothing.

105 }

99 }

106

100

101+mkAutoUpdate :: UpdateSettings a -> IO (IO a)

102+mkAutoUpdate us = mkAutoUpdateHelper us Nothing

103+

104+mkAutoUpdateWithModify :: UpdateSettings a -> (a -> IO a) -> IO (IO a)

105+mkAutoUpdateWithModify us f = mkAutoUpdateHelper us (Just f)

106+

107-- | Generate an action which will either read from an automatically

108-- updated value, or run the update action in the current thread.

109--

110-- @since 0.1.0

111−mkAutoUpdate :: UpdateSettings a -> IO (IO a)

111+mkAutoUpdateHelper :: UpdateSettings a -> Maybe (a -> IO a) -> IO (IO a)

112−mkAutoUpdate us = do

112+mkAutoUpdateHelper us updateActionModify = do

113 -- A baton to tell the worker thread to generate a new value.

114 needsRunning <- newEmptyMVar

115

157 takeMVar needsRunning

158

159 -- new value requested, so run the updateAction

160− a <- catchSome $ maybe (updateAction us) id (updateActionModify us <*> maybea)

160+ a <- catchSome $ maybe (updateAction us) id (updateActionModify <*> maybea)

161

162 -- we got a new value, update currRef and lastValue

163 writeIORef currRef $ Right a