Concurrent-Cache 0.1.0.2 → 0.2.0.0

raw patch · 3 files changed

+38/−22 lines, 3 filesPVP ok

version bump matches the API change (PVP)

API changes (from Hackage documentation)

Files

• ChangeLog.md +0/−5
• Concurrent-Cache.cabal +1/−2
• Control/Concurrent/Cache.hs +37/−15

@@ -1,5 +0,0 @@-# Revision history for Concurrent-Cache--## 0.1.0.0  -- YYYY-mm-dd--* First version. Released on an unsuspecting world.

@@ -2,7 +2,7 @@ -- documentation, see http://haskell.org/cabal/users-guide/  name:                Concurrent-Cache-version:             0.1.0.2+version:             0.2.0.0 synopsis:            A Cached variable for IO functions. description:         This package allows for caching IO functions, either on a                      timeout or designed to only fetch once.@@ -13,7 +13,6 @@ -- copyright:            category:            Concurrency build-type:          Simple-extra-source-files:  ChangeLog.md cabal-version:       >=1.10  library

@@ -1,11 +1,13 @@-module Control.Concurrent.Cache (CachedData, fetch, createCache) where+module Control.Concurrent.Cache (CachedData, fetch, createReadOnceCache, createTimedCache) where  import Data.Maybe (isNothing) import Control.Concurrent (forkIO, threadDelay, killThread, MVar, modifyMVar_, readMVar, ThreadId, newMVar) import Control.Monad (when, liftM) -data CachedData a = TimedCachedData (Int, (MVar (Maybe ThreadId, IO a, Maybe a))) | ReadOnceCachedData (MVar (Either (IO a) a))+data Timeout = TimeSinceCreation Int | TimeSinceLastRead Int  +data CachedData a = TimedCachedData (Timeout, (MVar (Maybe ThreadId, IO a, Maybe a))) | ReadOnceCachedData (MVar (Either (IO a) a))+ -- |Fetch data from a cache fetch :: CachedData a       -- ^ @Cache@, the cache to fetch a value from@@ -32,28 +34,48 @@                                           Just x -> return $ mvar'         go       Just value' -> do -        modifyMVar_ mvar $ \(thread', action', value') -> do-          when (not $ isNothing thread') $ let Just thread'' = thread' in killThread thread''-          newThreadId <- forkIO $ do-            threadDelay timeout-            modifyMVar_ mvar $ \(_, action'', _) -> return (Nothing, action'', Nothing)-          return (Just newThreadId, action', value')+        modifyMVar_ mvar $ \mvar'@(thread', action', value') -> do+          let newThread x = do threadDelay x+                               modifyMVar_ mvar $ \(_, action'', _) -> return (Nothing, action'', Nothing)+          case timeout of+               TimeSinceLastRead time -> do+                 when (not $ isNothing thread') $ let Just thread'' = thread' in killThread thread''+                 newThreadId <- forkIO $ newThread time+                 return (Just newThreadId, action', value')+               TimeSinceCreation time -> do+                 if (isNothing thread')+                    then do newThread' <- forkIO $ newThread time+                            return (Just newThread', action', value')+                    else return mvar'         return value'   -- |Create a cache with a timeout from an (IO ()) function.-createCache :: Int-            -- ^ @Timeout@ in microseconds before the cache is erased, 0 to-            -- disable emptying of the cache-            -> IO (a)+createReadOnceCache  :: IO (a)             -- ^ @Fetcher@, the function that returns the data which should             -- be cached. If @Timeout@ is not set to zero, this function             -- must be allowed to be called more than once.             -> IO (CachedData a)-createCache 0 action = do+createReadOnceCache action = do   var <- newMVar $ Left action   return $ ReadOnceCachedData var -createCache timeout action = do+-- |Create a cache with a timeout from an (IO ()) function.+createTimedCache  :: Int+            -- ^ @Timeout@ in microseconds before the cache is erased, 0 to+            -- disable emptying of the cache+            -> Bool+            -- ^ @resetTimerOnRead@, if true the timeout will be reset+            -- every time the cache is read, otherwise it will only be+            -- reset when the cached value is set.+            -> IO (a)+            -- ^ @Fetcher@, the function that returns the data which should+            -- be cached. If @Timeout@ is not set to zero, this function+            -- must be allowed to be called more than once.+            -> IO (CachedData a)+createTimedCache timeout resetOnRead action = do   var <- newMVar (Nothing, action, Nothing)-  return $ TimedCachedData (timeout, var)+  let timeout' = if resetOnRead+                   then TimeSinceLastRead timeout+                   else TimeSinceCreation timeout+  return $ TimedCachedData (timeout', var)