unliftio-0.2.25.0: The MonadUnliftIO typeclass for unlifting monads to IO (batteries included)

Safe Haskell | None
Language | Haskell2010

UnliftIO.Internals.Async

Contents

- We want to get rid of the Empty data constructor. We don't want
- We want to ensure that there is no nesting of Alt data
- We want to ensure that, when racing, we're always racing at least
- We want to simplify down to IO.

Synopsis

- async :: MonadUnliftIO m => m a -> m (Async a)
- asyncBound :: MonadUnliftIO m => m a -> m (Async a)
- asyncOn :: MonadUnliftIO m => Int -> m a -> m (Async a)
- asyncWithUnmask :: MonadUnliftIO m => ((forall b. m b -> m b) -> m a) -> m (Async a)
- asyncOnWithUnmask :: MonadUnliftIO m => Int -> ((forall b. m b -> m b) -> m a) -> m (Async a)
- withAsync :: MonadUnliftIO m => m a -> (Async a -> m b) -> m b
- withAsyncBound :: MonadUnliftIO m => m a -> (Async a -> m b) -> m b
- withAsyncOn :: MonadUnliftIO m => Int -> m a -> (Async a -> m b) -> m b
- withAsyncWithUnmask :: MonadUnliftIO m => ((forall c. m c -> m c) -> m a) -> (Async a -> m b) -> m b
- withAsyncOnWithUnmask :: MonadUnliftIO m => Int -> ((forall c. m c -> m c) -> m a) -> (Async a -> m b) -> m b
- wait :: MonadIO m => Async a -> m a
- poll :: MonadIO m => Async a -> m (Maybe (Either SomeException a))
- waitCatch :: MonadIO m => Async a -> m (Either SomeException a)
- cancel :: MonadIO m => Async a -> m ()
- uninterruptibleCancel :: MonadIO m => Async a -> m ()
- cancelWith :: (Exception e, MonadIO m) => Async a -> e -> m ()
- waitAny :: MonadIO m => [Async a] -> m (Async a, a)
- waitAnyCatch :: MonadIO m => [Async a] -> m (Async a, Either SomeException a)
- waitAnyCancel :: MonadIO m => [Async a] -> m (Async a, a)
- waitAnyCatchCancel :: MonadIO m => [Async a] -> m (Async a, Either SomeException a)
- waitEither :: MonadIO m => Async a -> Async b -> m (Either a b)
- waitEitherCatch :: MonadIO m => Async a -> Async b -> m (Either (Either SomeException a) (Either SomeException b))
- waitEitherCancel :: MonadIO m => Async a -> Async b -> m (Either a b)
- waitEitherCatchCancel :: MonadIO m => Async a -> Async b -> m (Either (Either SomeException a) (Either SomeException b))
- waitEither_ :: MonadIO m => Async a -> Async b -> m ()
- waitBoth :: MonadIO m => Async a -> Async b -> m (a, b)
- link :: MonadIO m => Async a -> m ()
- link2 :: MonadIO m => Async a -> Async b -> m ()
- race :: MonadUnliftIO m => m a -> m b -> m (Either a b)
- race_ :: MonadUnliftIO m => m a -> m b -> m ()
- concurrently :: MonadUnliftIO m => m a -> m b -> m (a, b)
- concurrently_ :: MonadUnliftIO m => m a -> m b -> m ()
- newtype Concurrently (m :: Type -> Type) a = Concurrently {
  - runConcurrently :: m a
  }
- forConcurrently :: (MonadUnliftIO m, Traversable t) => t a -> (a -> m b) -> m (t b)
- forConcurrently_ :: (MonadUnliftIO m, Foldable f) => f a -> (a -> m b) -> m ()
- replicateConcurrently :: MonadUnliftIO f => Int -> f a -> f [a]
- replicateConcurrently_ :: (Applicative m, MonadUnliftIO m) => Int -> m a -> m ()
- mapConcurrently :: (MonadUnliftIO m, Traversable t) => (a -> m b) -> t a -> m (t b)
- mapConcurrently_ :: (MonadUnliftIO m, Foldable f) => (a -> m b) -> f a -> m ()
- data Conc (m :: Type -> Type) a where
  - Action :: forall (m :: Type -> Type) a. m a -> Conc m a
  - Apply :: forall (m :: Type -> Type) v a. Conc m (v -> a) -> Conc m v -> Conc m a
  - LiftA2 :: forall x y a (m :: Type -> Type). (x -> y -> a) -> Conc m x -> Conc m y -> Conc m a
  - Pure :: forall a (m :: Type -> Type). a -> Conc m a
  - Alt :: forall (m :: Type -> Type) a. Conc m a -> Conc m a -> Conc m a
  - Empty :: forall (m :: Type -> Type) a. Conc m a
- conc :: m a -> Conc m a
- runConc :: MonadUnliftIO m => Conc m a -> m a
- data Flat a
  - = FlatApp !(FlatApp a)
  - | FlatAlt !(FlatApp a) !(FlatApp a) ![FlatApp a]
- data FlatApp a where
  - FlatPure :: forall a. a -> FlatApp a
  - FlatAction :: forall a. IO a -> FlatApp a
  - FlatApply :: forall v a. Flat (v -> a) -> Flat v -> FlatApp a
  - FlatLiftA2 :: forall x y a. (x -> y -> a) -> Flat x -> Flat y -> FlatApp a
- data ConcException = EmptyWithNoAlternative
- type DList a = [a] -> [a]
- dlistConcat :: DList a -> DList a -> DList a
- dlistCons :: a -> DList a -> DList a
- dlistConcatAll :: [DList a] -> DList a
- dlistToList :: DList a -> [a]
- dlistSingleton :: a -> DList a
- dlistEmpty :: DList a
- flatten :: MonadUnliftIO m => Conc m a -> m (Flat a)
- runFlat :: Flat a -> IO a
- pooledMapConcurrentlyN :: (MonadUnliftIO m, Traversable t) => Int -> (a -> m b) -> t a -> m (t b)
- pooledMapConcurrently :: (MonadUnliftIO m, Traversable t) => (a -> m b) -> t a -> m (t b)
- pooledForConcurrentlyN :: (MonadUnliftIO m, Traversable t) => Int -> t a -> (a -> m b) -> m (t b)
- pooledForConcurrently :: (MonadUnliftIO m, Traversable t) => t a -> (a -> m b) -> m (t b)
- pooledMapConcurrentlyIO :: Traversable t => Int -> (a -> IO b) -> t a -> IO (t b)
- pooledConcurrently :: Int -> IORef [a] -> (a -> IO ()) -> IO ()
- pooledMapConcurrentlyIO' :: Traversable t => Int -> (a -> IO b) -> t a -> IO (t b)
- pooledMapConcurrentlyIO_' :: Foldable t => Int -> (a -> IO ()) -> t a -> IO ()
- pooledMapConcurrentlyIO_ :: Foldable t => Int -> (a -> IO b) -> t a -> IO ()
- pooledMapConcurrentlyN_ :: (MonadUnliftIO m, Foldable f) => Int -> (a -> m b) -> f a -> m ()
- pooledMapConcurrently_ :: (MonadUnliftIO m, Foldable f) => (a -> m b) -> f a -> m ()
- pooledForConcurrently_ :: (MonadUnliftIO m, Foldable f) => f a -> (a -> m b) -> m ()
- pooledForConcurrentlyN_ :: (MonadUnliftIO m, Foldable t) => Int -> t a -> (a -> m b) -> m ()
- pooledReplicateConcurrentlyN :: MonadUnliftIO m => Int -> Int -> m a -> m [a]
- pooledReplicateConcurrently :: MonadUnliftIO m => Int -> m a -> m [a]
- pooledReplicateConcurrentlyN_ :: MonadUnliftIO m => Int -> Int -> m a -> m ()
- pooledReplicateConcurrently_ :: MonadUnliftIO m => Int -> m a -> m ()

# Documentation

async :: MonadUnliftIO m => m a -> m (Async a) #

Unlifted `async`.

Since: 0.1.0.0

asyncBound :: MonadUnliftIO m => m a -> m (Async a) #

Unlifted `asyncBound`.

Since: 0.1.0.0

asyncOn :: MonadUnliftIO m => Int -> m a -> m (Async a) #

Unlifted `asyncOn`.

Since: 0.1.0.0

asyncWithUnmask :: MonadUnliftIO m => ((forall b. m b -> m b) -> m a) -> m (Async a) #

Unlifted `asyncWithUnmask`.

Since: 0.1.0.0

asyncOnWithUnmask :: MonadUnliftIO m => Int -> ((forall b. m b -> m b) -> m a) -> m (Async a) #

Unlifted `asyncOnWithUnmask`.

Since: 0.1.0.0

withAsync :: MonadUnliftIO m => m a -> (Async a -> m b) -> m b #

Unlifted `withAsync`.

Since: 0.1.0.0

withAsyncBound :: MonadUnliftIO m => m a -> (Async a -> m b) -> m b #

Unlifted `withAsyncBound`.

Since: 0.1.0.0

withAsyncOn :: MonadUnliftIO m => Int -> m a -> (Async a -> m b) -> m b #

Unlifted `withAsyncOn`.

Since: 0.1.0.0

withAsyncWithUnmask :: MonadUnliftIO m => ((forall c. m c -> m c) -> m a) -> (Async a -> m b) -> m b #

Unlifted `withAsyncWithUnmask`.

Since: 0.1.0.0

withAsyncOnWithUnmask :: MonadUnliftIO m => Int -> ((forall c. m c -> m c) -> m a) -> (Async a -> m b) -> m b #

Unlifted `withAsyncOnWithMask`.

Since: 0.1.0.0

wait :: MonadIO m => Async a -> m a #

Lifted `wait`.

Since: 0.1.0.0

poll :: MonadIO m => Async a -> m (Maybe (Either SomeException a)) #

Lifted `poll`.

Since: 0.1.0.0

waitCatch :: MonadIO m => Async a -> m (Either SomeException a) #

Lifted `waitCatch`.

Since: 0.1.0.0

cancel :: MonadIO m => Async a -> m () #

Lifted `cancel`.

Since: 0.1.0.0

uninterruptibleCancel :: MonadIO m => Async a -> m () #

Lifted `uninterruptibleCancel`.

Since: 0.1.0.0

cancelWith :: (Exception e, MonadIO m) => Async a -> e -> m () #

Lifted `cancelWith`. Additionally uses `toAsyncException` to ensure async exception safety.

Since: 0.1.0.0

waitAny :: MonadIO m => [Async a] -> m (Async a, a) #

Lifted `waitAny`.

Since: 0.1.0.0

waitAnyCatch :: MonadIO m => [Async a] -> m (Async a, Either SomeException a) #

Lifted `waitAnyCatch`.

Since: 0.1.0.0

waitAnyCancel :: MonadIO m => [Async a] -> m (Async a, a) #

Lifted `waitAnyCancel`.

Since: 0.1.0.0

waitAnyCatchCancel :: MonadIO m => [Async a] -> m (Async a, Either SomeException a) #

Lifted `waitAnyCatchCancel`.

Since: 0.1.0.0

waitEither :: MonadIO m => Async a -> Async b -> m (Either a b) #

Lifted `waitEither`.

Since: 0.1.0.0

waitEitherCatch :: MonadIO m => Async a -> Async b -> m (Either (Either SomeException a) (Either SomeException b)) #

Lifted `waitEitherCatch`.

Since: 0.1.0.0

waitEitherCancel :: MonadIO m => Async a -> Async b -> m (Either a b) #

Lifted `waitEitherCancel`.

Since: 0.1.0.0

waitEitherCatchCancel :: MonadIO m => Async a -> Async b -> m (Either (Either SomeException a) (Either SomeException b)) #

Lifted `waitEitherCatchCancel`.

Since: 0.1.0.0

waitEither_ :: MonadIO m => Async a -> Async b -> m () #

Lifted `waitEither_`.

Since: 0.1.0.0

waitBoth :: MonadIO m => Async a -> Async b -> m (a, b) #

Lifted `waitBoth`.

Since: 0.1.0.0

link :: MonadIO m => Async a -> m () #

Lifted `link`.

Since: 0.1.0.0

link2 :: MonadIO m => Async a -> Async b -> m () #

Lifted `link2`.

Since: 0.1.0.0

race :: MonadUnliftIO m => m a -> m b -> m (Either a b) #

Unlifted `race`.

Since: 0.1.0.0

race_ :: MonadUnliftIO m => m a -> m b -> m () #

Unlifted `race_`.

Since: 0.1.0.0

concurrently :: MonadUnliftIO m => m a -> m b -> m (a, b) #

Unlifted `concurrently`.

Since: 0.1.0.0

concurrently_ :: MonadUnliftIO m => m a -> m b -> m () #

Unlifted `concurrently_`.

Since: 0.1.0.0

newtype Concurrently (m :: Type -> Type) a #

Unlifted `Concurrently`.

Since: 0.1.0.0

Constructors

Concurrently |
Fields runConcurrently :: m a

#### Instances

Instances details

MonadUnliftIO m => Alternative (Concurrently m) # | Composing two unlifted `Concurrently` values using `Alternative` is the equivalent to using a `race` combinator, the asynchrounous sub-routine that returns a value first is the one that gets it's value returned, the slowest sub-routine gets cancelled and it's thread is killed. Since: 0.1.0.0
Instance details Defined in UnliftIO.Internals.Async Methods empty :: Concurrently m a # (<|>) :: Concurrently m a -> Concurrently m a -> Concurrently m a # some :: Concurrently m a -> Concurrently m [a] # many :: Concurrently m a -> Concurrently m [a] #
MonadUnliftIO m => Applicative (Concurrently m) # | Since: 0.1.0.0
Instance details Defined in UnliftIO.Internals.Async Methods pure :: a -> Concurrently m a # (<*>) :: Concurrently m (a -> b) -> Concurrently m a -> Concurrently m b # liftA2 :: (a -> b -> c) -> Concurrently m a -> Concurrently m b -> Concurrently m c # (*>) :: Concurrently m a -> Concurrently m b -> Concurrently m b # (<*) :: Concurrently m a -> Concurrently m b -> Concurrently m a #
Monad m => Functor (Concurrently m) # | Since: 0.1.0.0
Instance details Defined in UnliftIO.Internals.Async Methods fmap :: (a -> b) -> Concurrently m a -> Concurrently m b # (<$) :: a -> Concurrently m b -> Concurrently m a #
(Semigroup a, Monoid a, MonadUnliftIO m) => Monoid (Concurrently m a) # | Since: 0.1.0.0
Instance details Defined in UnliftIO.Internals.Async Methods mempty :: Concurrently m a # mappend :: Concurrently m a -> Concurrently m a -> Concurrently m a # mconcat :: [Concurrently m a] -> Concurrently m a #
(MonadUnliftIO m, Semigroup a) => Semigroup (Concurrently m a) # | Only defined by `async` for `base >= 4.9`. Since: 0.1.0.0
Instance details Defined in UnliftIO.Internals.Async Methods (<>) :: Concurrently m a -> Concurrently m a -> Concurrently m a # sconcat :: NonEmpty (Concurrently m a) -> Concurrently m a # stimes :: Integral b => b -> Concurrently m a -> Concurrently m a #

forConcurrently :: (MonadUnliftIO m, Traversable t) => t a -> (a -> m b) -> m (t b) #

Similar to `mapConcurrently` but with arguments flipped

Since: 0.1.0.0

forConcurrently_ :: (MonadUnliftIO m, Foldable f) => f a -> (a -> m b) -> m () #

Similar to `mapConcurrently_` but with arguments flipped

Since: 0.1.0.0

replicateConcurrently :: MonadUnliftIO f => Int -> f a -> f [a] #

Unlifted `replicateConcurrently`.

Since: 0.1.0.0

replicateConcurrently_ :: (Applicative m, MonadUnliftIO m) => Int -> m a -> m () #

Unlifted `replicateConcurrently_`.

Since: 0.1.0.0

mapConcurrently :: (MonadUnliftIO m, Traversable t) => (a -> m b) -> t a -> m (t b) #

Executes a `Traversable` container of items concurrently, it uses the `Flat` type internally.

Since: 0.1.0.0

mapConcurrently_ :: (MonadUnliftIO m, Foldable f) => (a -> m b) -> f a -> m () #

Executes a `Traversable` container of items concurrently, it uses the `Flat` type internally. This function ignores the results.

Since: 0.1.0.0

data Conc (m :: Type -> Type) a where #

A more efficient alternative to `Concurrently`, which reduces the number of threads that need to be forked. For more information, see this blog post. This is provided as a separate type to `Concurrently` as it has a slightly different API.

Use the `conc` function to construct values of type `Conc`, and `runConc` to execute the composed actions. You can use the `Applicative` instance to run different actions and wait for all of them to complete, or the `Alternative` instance to wait for the first thread to complete.

In the event of a runtime exception thrown by any of the children threads, or an asynchronous exception received in the parent thread, all threads will be killed with an `AsyncCancelled` exception and the original exception rethrown. If multiple exceptions are generated by different threads, there are no guarantees on which exception will end up getting rethrown.

For many common use cases, you may prefer using helper functions in this module like `mapConcurrently`.

There are some intentional differences in behavior to `Concurrently`:

- Children threads are always launched in an unmasked state, not the inherited state of the parent thread.

Note that it is a programmer error to use the `Alternative` instance in such a way that there are no alternatives to an empty, e.g. `runConc (empty | empty)`. In such a case, a `ConcException` will be thrown. If there was an `Alternative` in the standard libraries without `empty`, this library would use it instead.

Since: 0.2.9.0

Constructors

Action :: forall (m :: Type -> Type) a. m a -> Conc m a |
Apply :: forall (m :: Type -> Type) v a. Conc m (v -> a) -> Conc m v -> Conc m a |
LiftA2 :: forall x y a (m :: Type -> Type). (x -> y -> a) -> Conc m x -> Conc m y -> Conc m a |
Pure :: forall a (m :: Type -> Type). a -> Conc m a |
Alt :: forall (m :: Type -> Type) a. Conc m a -> Conc m a -> Conc m a |
Empty :: forall (m :: Type -> Type) a. Conc m a |

#### Instances

Instances details

MonadUnliftIO m => Alternative (Conc m) # | Since: 0.2.9.0
Instance details Defined in UnliftIO.Internals.Async Methods empty :: Conc m a # (<|>) :: Conc m a -> Conc m a -> Conc m a # some :: Conc m a -> Conc m [a] # many :: Conc m a -> Conc m [a] #
MonadUnliftIO m => Applicative (Conc m) # | Since: 0.2.9.0
Instance details Defined in UnliftIO.Internals.Async Methods pure :: a -> Conc m a # (<*>) :: Conc m (a -> b) -> Conc m a -> Conc m b # liftA2 :: (a -> b -> c) -> Conc m a -> Conc m b -> Conc m c # (*>) :: Conc m a -> Conc m b -> Conc m b # (<*) :: Conc m a -> Conc m b -> Conc m a #
Functor m => Functor (Conc m) # |
Instance details Defined in UnliftIO.Internals.Async Methods fmap :: (a -> b) -> Conc m a -> Conc m b # (<$) :: a -> Conc m b -> Conc m a #
(Monoid a, MonadUnliftIO m) => Monoid (Conc m a) # | Since: 0.2.9.0
Instance details Defined in UnliftIO.Internals.Async Methods mempty :: Conc m a # mappend :: Conc m a -> Conc m a -> Conc m a # mconcat :: [Conc m a] -> Conc m a #
(MonadUnliftIO m, Semigroup a) => Semigroup (Conc m a) # | Since: 0.2.9.0
Instance details Defined in UnliftIO.Internals.Async Methods (<>) :: Conc m a -> Conc m a -> Conc m a # sconcat :: NonEmpty (Conc m a) -> Conc m a # stimes :: Integral b => b -> Conc m a -> Conc m a #

conc :: m a -> Conc m a #

Construct a value of type `Conc` from an action. Compose these values using the typeclass instances (most commonly `Applicative` and `Alternative`) and then run with `runConc`.

Since: 0.2.9.0

runConc :: MonadUnliftIO m => Conc m a -> m a #

Run a `Conc` value on multiple threads.

Since: 0.2.9.0

# We want to get rid of the Empty data constructor. We don't want

# We want to ensure that there is no nesting of Alt data

# We want to ensure that, when racing, we're always racing at least

# We want to simplify down to IO.

data Flat a #

Flattened structure, either Applicative or Alternative

Constructors

FlatApp !(FlatApp a) |
FlatAlt !(FlatApp a) !(FlatApp a) ![FlatApp a] | Flattened Alternative. Has at least 2 entries, which must be FlatApp (no nesting of FlatAlts).

#### Instances

Instances details

Applicative Flat # |
Instance details Defined in UnliftIO.Internals.Async Methods pure :: a -> Flat a # (<*>) :: Flat (a -> b) -> Flat a -> Flat b # liftA2 :: (a -> b -> c) -> Flat a -> Flat b -> Flat c # (*>) :: Flat a -> Flat b -> Flat b # (<*) :: Flat a -> Flat b -> Flat a #
Functor Flat # |
Instance details Defined in UnliftIO.Internals.Async Methods fmap :: (a -> b) -> Flat a -> Flat b # (<$) :: a -> Flat b -> Flat a #

data FlatApp a where #

Flattened Applicative. No Alternative stuff directly in here, but may be in the children. Notice this type doesn't have a type parameter for monadic contexts, it hardwires the base monad to IO given concurrency relies eventually on that.

Since: 0.2.9.0

Constructors

FlatPure :: forall a. a -> FlatApp a |
FlatAction :: forall a. IO a -> FlatApp a |
FlatApply :: forall v a. Flat (v -> a) -> Flat v -> FlatApp a |
FlatLiftA2 :: forall x y a. (x -> y -> a) -> Flat x -> Flat y -> FlatApp a |

#### Instances

Instances details

Applicative FlatApp # |
Instance details Defined in UnliftIO.Internals.Async Methods pure :: a -> FlatApp a # (<*>) :: FlatApp (a -> b) -> FlatApp a -> FlatApp b # liftA2 :: (a -> b -> c) -> FlatApp a -> FlatApp b -> FlatApp c # (*>) :: FlatApp a -> FlatApp b -> FlatApp b # (<*) :: FlatApp a -> FlatApp b -> FlatApp a #
Functor FlatApp # |
Instance details Defined in UnliftIO.Internals.Async Methods fmap :: (a -> b) -> FlatApp a -> FlatApp b # (<$) :: a -> FlatApp b -> FlatApp a #

data ConcException #

Things that can go wrong in the structure of a `Conc`. These are programmer errors.

Since: 0.2.9.0

Constructors

EmptyWithNoAlternative |

#### Instances

Instances details

Exception ConcException # |
Instance details Defined in UnliftIO.Internals.Async Methods toException :: ConcException -> SomeException # fromException :: SomeException -> Maybe ConcException # displayException :: ConcException -> String #
Generic ConcException # |
Instance details Defined in UnliftIO.Internals.Async Associated Types
type Rep ConcException |
Instance details Defined in UnliftIO.Internals.Async type Rep ConcException = D1 ('MetaData "ConcException" "UnliftIO.Internals.Async" "unliftio-0.2.25.0-LDIKVxabye145Ny8GsAEcd" 'False) (C1 ('MetaCons "EmptyWithNoAlternative" 'PrefixI 'False) (U1 :: Type -> Type))
Methods from :: ConcException -> Rep ConcException x # to :: Rep ConcException x -> ConcException #
Show ConcException # |
Instance details Defined in UnliftIO.Internals.Async Methods showsPrec :: Int -> ConcException -> ShowS # show :: ConcException -> String # showList :: [ConcException] -> ShowS #
Eq ConcException # |
Instance details Defined in UnliftIO.Internals.Async Methods (==) :: ConcException -> ConcException -> Bool # (/=) :: ConcException -> ConcException -> Bool #
Ord ConcException # |
Instance details Defined in UnliftIO.Internals.Async Methods compare :: ConcException -> ConcException -> Ordering # (<) :: ConcException -> ConcException -> Bool # (<=) :: ConcException -> ConcException -> Bool # (>) :: ConcException -> ConcException -> Bool # (>=) :: ConcException -> ConcException -> Bool # max :: ConcException -> ConcException -> ConcException # min :: ConcException -> ConcException -> ConcException #
type Rep ConcException # |
Instance details Defined in UnliftIO.Internals.Async type Rep ConcException = D1 ('MetaData "ConcException" "UnliftIO.Internals.Async" "unliftio-0.2.25.0-LDIKVxabye145Ny8GsAEcd" 'False) (C1 ('MetaCons "EmptyWithNoAlternative" 'PrefixI 'False) (U1 :: Type -> Type))

type DList a = [a] -> [a] #

Simple difference list, for nicer types below

dlistConcat :: DList a -> DList a -> DList a #

dlistCons :: a -> DList a -> DList a #

dlistConcatAll :: [DList a] -> DList a #

dlistToList :: DList a -> [a] #

dlistSingleton :: a -> DList a #

dlistEmpty :: DList a #

flatten :: MonadUnliftIO m => Conc m a -> m (Flat a) #

Turn a `Conc` into a `Flat`. Note that thanks to the ugliness of `empty`, this may fail, e.g. `flatten Empty`.

Since: 0.2.9.0

runFlat :: Flat a -> IO a #

Run a `Flat a` on multiple threads.

pooledMapConcurrentlyN #

Arguments

:: (MonadUnliftIO m, Traversable t) |
=> Int | Max. number of threads. Should not be less than 1.
-> (a -> m b) |
-> t a |
-> m (t b) |

Like `mapConcurrently` from async, but instead of one thread per element, it does pooling from a set of threads. This is useful in scenarios where resource consumption is bounded and for use cases where too many concurrent tasks aren't allowed.

### Example usage

Expand

    import Say

    action :: Int -> IO Int
    action n = do
      tid <- myThreadId
      sayString $ show tid
      threadDelay (2 * 10^6) -- 2 seconds
      return n

    main :: IO ()
    main = do
      yx <- pooledMapConcurrentlyN 5 (\x -> action x) [1..5]
      print yx

On executing you can see that five threads have been spawned:

    $ ./pool
    ThreadId 36
    ThreadId 38
    ThreadId 40
    ThreadId 42
    ThreadId 44
    [1,2,3,4,5]

Let's modify the above program such that there are less threads than the number of items in the list:

    import Say

    action :: Int -> IO Int
    action n = do
      tid <- myThreadId
      sayString $ show tid
      threadDelay (2 * 10^6) -- 2 seconds
      return n

    main :: IO ()
    main = do
      yx <- pooledMapConcurrentlyN 3 (\x -> action x) [1..5]
      print yx

On executing you can see that only three threads are active totally:

    $ ./pool
    ThreadId 35
    ThreadId 37
    ThreadId 39
    ThreadId 35
    ThreadId 39
    [1,2,3,4,5]

Since: 0.2.10

pooledMapConcurrently :: (MonadUnliftIO m, Traversable t) => (a -> m b) -> t a -> m (t b) #

Similar to `pooledMapConcurrentlyN` but with number of threads set from `getNumCapabilities`. Usually this is useful for CPU bound tasks.

Since: 0.2.10

pooledForConcurrentlyN #

Arguments

:: (MonadUnliftIO m, Traversable t) |
=> Int | Max. number of threads. Should not be less than 1.
-> t a |
-> (a -> m b) |
-> m (t b) |

Similar to `pooledMapConcurrentlyN` but with flipped arguments.

Since: 0.2.10

pooledForConcurrently :: (MonadUnliftIO m, Traversable t) => t a -> (a -> m b) -> m (t b) #

Similar to `pooledForConcurrentlyN` but with number of threads set from `getNumCapabilities`. Usually this is useful for CPU bound tasks.

Since: 0.2.10

pooledMapConcurrentlyIO :: Traversable t => Int -> (a -> IO b) -> t a -> IO (t b) #

pooledConcurrently #

Arguments

:: Int | Max. number of threads. Should not be less than 1.
-> IORef [a] | Task queue. These are required as inputs for the jobs.
-> (a -> IO ()) | The task which will be run concurrently (but will be pooled properly).
-> IO () |

Performs the actual pooling for the tasks. This function will continue execution until the task queue becomes empty. When one of the pooled thread finishes it's task, it will pickup the next task from the queue if an job is available.

pooledMapConcurrentlyIO' #

Arguments

:: Traversable t |
=> Int | Max. number of threads. Should not be less than 1.
-> (a -> IO b) |
-> t a |
-> IO (t b) |

pooledMapConcurrentlyIO_' :: Foldable t => Int -> (a -> IO ()) -> t a -> IO () #

pooledMapConcurrentlyIO_ :: Foldable t => Int -> (a -> IO b) -> t a -> IO () #

pooledMapConcurrentlyN_ #

Arguments

:: (MonadUnliftIO m, Foldable f) |
=> Int | Max. number of threads. Should not be less than 1.
-> (a -> m b) |
-> f a |
-> m () |

Like `pooledMapConcurrentlyN` but with the return value discarded.

Since: 0.2.10

pooledMapConcurrently_ :: (MonadUnliftIO m, Foldable f) => (a -> m b) -> f a -> m () #

Like `pooledMapConcurrently` but with the return value discarded.

Since: 0.2.10

pooledForConcurrently_ :: (MonadUnliftIO m, Foldable f) => f a -> (a -> m b) -> m () #

Like `pooledMapConcurrently_` but with flipped arguments.

Since: 0.2.10

pooledForConcurrentlyN_ #

Arguments

:: (MonadUnliftIO m, Foldable t) |
=> Int | Max. number of threads. Should not be less than 1.
-> t a |
-> (a -> m b) |
-> m () |

Like `pooledMapConcurrentlyN_` but with flipped arguments.

Since: 0.2.10

pooledReplicateConcurrentlyN #

Arguments

:: MonadUnliftIO m |
=> Int | Max. number of threads. Should not be less than 1.
-> Int | Number of times to perform the action.
-> m a |
-> m [a] |

Pooled version of `replicateConcurrently`. Performs the action in the pooled threads.

Since: 0.2.10

pooledReplicateConcurrently #

Arguments

:: MonadUnliftIO m |
=> Int | Number of times to perform the action.
-> m a |
-> m [a] |

Similar to `pooledReplicateConcurrentlyN` but with number of threads set from `getNumCapabilities`. Usually this is useful for CPU bound tasks.

Since: 0.2.10

pooledReplicateConcurrentlyN_ #

Arguments

:: MonadUnliftIO m |
=> Int | Max. number of threads. Should not be less than 1.
-> Int | Number of times to perform the action.
-> m a |
-> m () |

Pooled version of `replicateConcurrently_`. Performs the action in the pooled threads.

Since: 0.2.10

pooledReplicateConcurrently_ #

Arguments

:: MonadUnliftIO m |
=> Int | Number of times to perform the action.
-> m a |
-> m () |

Similar to `pooledReplicateConcurrently_` but with number of threads set from `getNumCapabilities`. Usually this is useful for CPU bound tasks.

Since: 0.2.10