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Make MonadMask a requirement for MonadConc

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This commit is contained in:
Michael Walker 2015-02-13 17:47:04 +00:00
parent 8faee29b27
commit f18209f2e0
3 changed files with 185 additions and 40 deletions
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61
Control/Monad/Conc/Class.hs
View File

@ -1,4 +1,5 @@
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE RankNTypes #-}
{-# LANGUAGE TypeFamilies #-}
-- | This module captures in a typeclass the interface of concurrency
@ -7,17 +8,19 @@ module Control.Monad.Conc.Class
( MonadConc(..)
-- * Utilities
, spawn
, forkFinally
, killThread
) where
import Control.Concurrent (forkIO)
import Control.Concurrent.MVar (MVar, readMVar, newEmptyMVar, putMVar, tryPutMVar, takeMVar, tryTakeMVar)
import Control.Exception (Exception, AsyncException(ThreadKilled))
import Control.Exception (Exception, AsyncException(ThreadKilled), SomeException)
import Control.Monad (unless)
import Control.Monad.Catch (MonadCatch, MonadThrow, catch, throwM)
import Control.Monad.Catch (MonadCatch, MonadThrow, MonadMask)
import Control.Monad.STM (STM)
import Control.Monad.STM.Class (MonadSTM)
import qualified Control.Monad.Catch as Ca
import qualified Control.Concurrent as C
import qualified Control.Monad.STM as S
@ -44,7 +47,7 @@ import qualified Control.Monad.STM as S
-- 'takeCVar' and 'putCVar', however, are very inefficient, and should
-- probably always be overridden to make use of
-- implementation-specific blocking functionality.
class ( Monad m, MonadCatch m, MonadThrow m
class ( Monad m, MonadCatch m, MonadThrow m, MonadMask m
, MonadSTM (STMLike m)
, Eq (ThreadId m), Show (ThreadId m)) => MonadConc m where
-- | The associated 'MonadSTM' for this class.
@ -63,6 +66,10 @@ class ( Monad m, MonadCatch m, MonadThrow m
-- happen over @CVar@s.
fork :: m () -> m (ThreadId m)
-- | Like 'fork', but the child thread is passed a function that can
-- be used to unmask asynchronous exceptions.
forkWithUnmask :: ((forall a. m a -> m a) -> m ()) -> m (ThreadId m)
-- | Get the @ThreadId@ of the current thread.
myThreadId :: m (ThreadId m)
@ -107,22 +114,52 @@ class ( Monad m, MonadCatch m, MonadThrow m
-- exception handler capable of dealing with it and, if one is not
-- found, the thread is killed.
--
-- > throw = throwM
-- > throw = Control.Monad.Catch.throwM
throw :: Exception e => e -> m a
throw = throwM
throw = Ca.throwM
-- | Catch an exception. This is only required to be able to catch
-- exceptions raised by 'throw', unlike the more general
-- Control.Exception.catch function. If you need to be able to catch
-- /all/ errors, you will have to use 'IO'.
--
-- > catch = Control.Monad.Catch.catch
catch :: Exception e => m a -> (e -> m a) -> m a
catch = Control.Monad.Catch.catch
catch = Ca.catch
-- | Throw an exception to the target thread. This blocks until the
-- exception is delivered, and it is just as if the target thread
-- had raised it with 'throw'. This can interrupt a blocked action.
throwTo :: Exception e => ThreadId m => e -> m ()
-- | Executes a computation with asynchronous exceptions
-- /masked/. That is, any thread which attempts to raise an
-- exception in the current thread with 'throwTo' will be blocked
-- until asynchronous exceptions are unmasked again.
--
-- The argument passed to mask is a function that takes as its
-- argument another function, which can be used to restore the
-- prevailing masking state within the context of the masked
-- computation.
--
-- > mask = Control.Monad.Catch.mask
mask :: ((forall a. m a -> m a) -> m b) -> m b
mask = Ca.mask
-- | Like 'mask', but the masked computation is not
-- interruptible. THIS SHOULD BE USED WITH GREAT CARE, because if a
-- thread executing in 'uninterruptibleMask' blocks for any reason,
-- then the thread (and possibly the program, if this is the main
-- thread) will be unresponsive and unkillable. This function should
-- only be necessary if you need to mask exceptions around an
-- interruptible operation, and you can guarantee that the
-- interruptible operation will only block for a short period of
-- time.
--
-- > uninterruptibleMask = Control.Monad.Catch.uninterruptibleMask
uninterruptibleMask :: ((forall a. m a -> m a) -> m b) -> m b
uninterruptibleMask = Ca.uninterruptibleMask
-- | Runs its argument, just as if the @_concNoTest@ weren't there.
--
-- > _concNoTest x = x
@ -151,6 +188,7 @@ instance MonadConc IO where
readCVar = readMVar
fork = forkIO
forkWithUnmask = C.forkIOWithUnmask
myThreadId = C.myThreadId
throwTo = C.throwTo
newEmptyCVar = newEmptyMVar
@ -168,6 +206,17 @@ spawn ma = do
_ <- fork $ ma >>= putCVar cvar
return cvar
-- | Fork a thread and call the supplied function when the thread is
-- about to terminate, with an exception or a returned value. The
-- function is called with asynchronous exceptions masked.
--
-- This function is useful for informing the parent when a child
-- terminates, for example.
forkFinally :: MonadConc m => m a -> (Either SomeException a -> m ()) -> m (ThreadId m)
forkFinally action and_then =
mask $ \restore ->
fork $ Ca.try (restore action) >>= and_then
-- | Raise the 'ThreadKilled' exception in the target thread. Note
-- that if the thread is prepared to catch this exception, it won't
-- actually kill it.

50
Test/DejaFu/Deterministic.hs
View File

@ -1,5 +1,5 @@
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
{-# LANGUAGE Rank2Types #-}
{-# LANGUAGE RankNTypes #-}
{-# LANGUAGE TypeFamilies #-}
-- | Deterministic traced execution of concurrent computations which
@ -14,6 +14,8 @@ module Test.DejaFu.Deterministic
, Failure(..)
, runConc
, fork
, forkFinally
, forkWithUnmask
, myThreadId
, spawn
, atomically
@ -21,6 +23,8 @@ module Test.DejaFu.Deterministic
, throwTo
, killThread
, catch
, mask
, uninterruptibleMask
-- * Communication: CVars
, CVar
@ -70,12 +74,17 @@ instance Ca.MonadCatch (Conc t) where
instance Ca.MonadThrow (Conc t) where
throwM = throw
instance Ca.MonadMask (Conc t) where
mask = mask
uninterruptibleMask = uninterruptibleMask
instance C.MonadConc (Conc t) where
type CVar (Conc t) = CVar t
type STMLike (Conc t) = STMLike t (ST t) (STRef t)
type ThreadId (Conc t) = Int
fork = fork
forkWithUnmask = forkWithUnmask
myThreadId = myThreadId
throwTo = throwTo
newEmptyCVar = newEmptyCVar
@ -170,6 +179,45 @@ killThread = C.killThread
catch :: Exception e => Conc t a -> (e -> Conc t a) -> Conc t a
catch ma h = C $ cont $ ACatching (unC . h) (unC ma)
-- | Fork a thread and call the supplied function when the thread is
-- about to terminate, with an exception or a returned value. The
-- function is called with asynchronous exceptions masked.
--
-- This function is useful for informing the parent when a child
-- terminates, for example.
forkFinally :: Conc t a -> (Either SomeException a -> Conc t ()) -> Conc t ThreadId
forkFinally action and_then =
mask $ \restore ->
fork $ Ca.try (restore action) >>= and_then
-- | Like 'fork', but the child thread is passed a function that can
-- be used to unmask asynchronous exceptions.
forkWithUnmask :: ((forall a. Conc t a -> Conc t a) -> Conc t ()) -> Conc t ThreadId
forkWithUnmask = error "'forkWithUnmask' not yet implemented for 'Conc'"
-- | Executes a computation with asynchronous exceptions
-- /masked/. That is, any thread which attempts to raise an exception
-- in the current thread with 'throwTo' will be blocked until
-- asynchronous exceptions are unmasked again.
--
-- The argument passed to mask is a function that takes as its
-- argument another function, which can be used to restore the
-- prevailing masking state within the context of the masked
-- computation.
mask :: ((forall a. Conc t a -> Conc t a) -> Conc t b) -> Conc t b
mask = error "'mask' not yet implemented for 'Conc'"
-- | Like 'mask', but the masked computation is not
-- interruptible. THIS SHOULD BE USED WITH GREAT CARE, because if a
-- thread executing in 'uninterruptibleMask' blocks for any reason,
-- then the thread (and possibly the program, if this is the main
-- thread) will be unresponsive and unkillable. This function should
-- only be necessary if you need to mask exceptions around an
-- interruptible operation, and you can guarantee that the
-- interruptible operation will only block for a short period of time.
uninterruptibleMask :: ((forall a. Conc t a -> Conc t a) -> Conc t b) -> Conc t b
uninterruptibleMask = error "'uninterruptibleMask' not yet implemented for 'Conc'"
-- | Run the argument in one step. If the argument fails, the whole
-- computation will fail.
_concNoTest :: Conc t a -> Conc t a

50
Test/DejaFu/Deterministic/IO.hs
View File

@ -1,5 +1,5 @@
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
{-# LANGUAGE Rank2Types #-}
{-# LANGUAGE RankNTypes #-}
{-# LANGUAGE TypeFamilies #-}
-- | Deterministic traced execution of concurrent computations which
@ -18,6 +18,8 @@ module Test.DejaFu.Deterministic.IO
, runConcIO
, liftIO
, fork
, forkFinally
, forkWithUnmask
, myThreadId
, spawn
, atomically
@ -25,6 +27,8 @@ module Test.DejaFu.Deterministic.IO
, throwTo
, killThread
, catch
, mask
, uninterruptibleMask
-- * Communication: CVars
, CVar
@ -71,6 +75,10 @@ instance Ca.MonadCatch (ConcIO t) where
instance Ca.MonadThrow (ConcIO t) where
throwM = throw
instance Ca.MonadMask (ConcIO t) where
mask = mask
uninterruptibleMask = uninterruptibleMask
instance IO.MonadIO (ConcIO t) where
liftIO = liftIO
@ -80,6 +88,7 @@ instance C.MonadConc (ConcIO t) where
type ThreadId (ConcIO t) = Int
fork = fork
forkWithUnmask = forkWithUnmask
myThreadId = myThreadId
throwTo = throwTo
newEmptyCVar = newEmptyCVar
@ -175,6 +184,45 @@ killThread = C.killThread
catch :: Exception e => ConcIO t a -> (e -> ConcIO t a) -> ConcIO t a
catch ma h = C $ cont $ ACatching (unC . h) (unC ma)
-- | Fork a thread and call the supplied function when the thread is
-- about to terminate, with an exception or a returned value. The
-- function is called with asynchronous exceptions masked.
--
-- This function is useful for informing the parent when a child
-- terminates, for example.
forkFinally :: ConcIO t a -> (Either SomeException a -> ConcIO t ()) -> ConcIO t ThreadId
forkFinally action and_then =
mask $ \restore ->
fork $ Ca.try (restore action) >>= and_then
-- | Like 'fork', but the child thread is passed a function that can
-- be used to unmask asynchronous exceptions.
forkWithUnmask :: ((forall a. ConcIO t a -> ConcIO t a) -> ConcIO t ()) -> ConcIO t ThreadId
forkWithUnmask = error "'forkWithUnmask' not yet implemented for 'ConcIO'"
-- | Executes a computation with asynchronous exceptions
-- /masked/. That is, any thread which attempts to raise an exception
-- in the current thread with 'throwTo' will be blocked until
-- asynchronous exceptions are unmasked again.
--
-- The argument passed to mask is a function that takes as its
-- argument another function, which can be used to restore the
-- prevailing masking state within the context of the masked
-- computation.
mask :: ((forall a. ConcIO t a -> ConcIO t a) -> ConcIO t b) -> ConcIO t b
mask = error "'mask' not yet implemented for 'ConcIO'"
-- | Like 'mask', but the masked computation is not
-- interruptible. THIS SHOULD BE USED WITH GREAT CARE, because if a
-- thread executing in 'uninterruptibleMask' blocks for any reason,
-- then the thread (and possibly the program, if this is the main
-- thread) will be unresponsive and unkillable. This function should
-- only be necessary if you need to mask exceptions around an
-- interruptible operation, and you can guarantee that the
-- interruptible operation will only block for a short period of time.
uninterruptibleMask :: ((forall a. ConcIO t a -> ConcIO t a) -> ConcIO t b) -> ConcIO t b
uninterruptibleMask = error "'uninterruptibleMask' not yet implemented for 'ConcIO'"
-- | Run the argument in one step. If the argument fails, the whole
-- computation will fail.
_concNoTest :: ConcIO t a -> ConcIO t a