UnliftIO.MessageBox.Class

This module contains a type class that describes exchangable operations on messages boxes.

Documentation

class (IsMessageBox (MessageBox argument), IsInput (Input (MessageBox argument))) => IsMessageBoxArg argument where

Types that configure and allow the creation of a MessageBox.

Create IsMessageBox instances from a parameter. Types that determine MessageBox values.

For a limited message box this might be the limit of the message queue.

Associated Types

type MessageBox argument :: Type -> Type

The message box that can be created from the message box argument

Methods

getConfiguredMessageLimit :: argument -> Maybe Int

Return a message limit.

NOTE: This method was added for unit tests. Although the method is totally valid, it might not be super useful in production code. Also note that the naming follows the rule: Reserve short names for entities that are used often.

newMessageBox :: MonadUnliftIO m => argument -> m (MessageBox argument a)

Create a new msgBox according to the argument. This is required to receive a message. NOTE: Only one process may receive on an msgBox.

Instances

IsMessageBoxArg BlockingUnlimited

Defined in UnliftIO.MessageBox.Unlimited

Associated Types

type MessageBox BlockingUnlimited :: Type -> Type

Methods

getConfiguredMessageLimit :: BlockingUnlimited -> Maybe Int

newMessageBox :: MonadUnliftIO m => BlockingUnlimited -> m (MessageBox BlockingUnlimited a)

IsMessageBoxArg WaitingBoxLimit

Defined in UnliftIO.MessageBox.Limited

Associated Types

type MessageBox WaitingBoxLimit :: Type -> Type

Methods

getConfiguredMessageLimit :: WaitingBoxLimit -> Maybe Int

newMessageBox :: MonadUnliftIO m => WaitingBoxLimit -> m (MessageBox WaitingBoxLimit a)

IsMessageBoxArg NonBlockingBoxLimit

Defined in UnliftIO.MessageBox.Limited

Associated Types

type MessageBox NonBlockingBoxLimit :: Type -> Type

Methods

getConfiguredMessageLimit :: NonBlockingBoxLimit -> Maybe Int

newMessageBox :: MonadUnliftIO m => NonBlockingBoxLimit -> m (MessageBox NonBlockingBoxLimit a)

IsMessageBoxArg BlockingBoxLimit

Defined in UnliftIO.MessageBox.Limited

Associated Types

type MessageBox BlockingBoxLimit :: Type -> Type

Methods

getConfiguredMessageLimit :: BlockingBoxLimit -> Maybe Int

newMessageBox :: MonadUnliftIO m => BlockingBoxLimit -> m (MessageBox BlockingBoxLimit a)

IsMessageBoxArg cfg => IsMessageBoxArg (CatchAllArg cfg)

Defined in UnliftIO.MessageBox.CatchAll

Associated Types

type MessageBox (CatchAllArg cfg) :: Type -> Type

Methods

getConfiguredMessageLimit :: CatchAllArg cfg -> Maybe Int

newMessageBox :: MonadUnliftIO m => CatchAllArg cfg -> m (MessageBox (CatchAllArg cfg) a)

class IsInput (Input box) => IsMessageBox box where

A type class for msgBox types. A common interface for receiving messages.

Minimal complete definition

receive, tryReceive, newInput

Associated Types

type Input box :: Type -> Type

Type of the corresponding input

Methods

receive :: MonadUnliftIO m => box a -> m (Maybe a)

Receive a message. Take whatever time it takes. Return Just the value or Nothing when an error occurred.

NOTE: Nothing may sporadically be returned, especially when there is a lot of load, so please make sure to build your application in such a way, that it anticipates failure.

tryReceive :: MonadUnliftIO m => box a -> m (Future a)

Return a Future that can be used to wait for the arrival of the next message. NOTE: Each future value represents the next slot in the queue so one future corresponds to exactly that message (should it arrive) and if that future value is dropped, that message will be lost!

receiveAfter

Arguments

:: MonadUnliftIO m

=> box a

Message box

-> Int

Time in micro seconds to wait until the action is invoked.

-> m (Maybe a)

Wait for an incoming message or return Nothing.

The default implementation uses tryReceive to get a Future on which awaitFuture inside a timeout is called.

Instances might override this with more performant implementations especially non-blocking Unagi channel based implementation.

NOTE: Nothing may sporadically be returned, especially when there is a lot of load, so please make sure to build your application in such a way, that it anticipates failure.

newInput :: MonadUnliftIO m => box a -> m (Input box a)

Create a new input that enqueus messages, which are received by the box

Instances

IsMessageBox UnlimitedBox

A blocking instance that invokes receive.

Defined in UnliftIO.MessageBox.Unlimited

Associated Types

type Input UnlimitedBox :: Type -> Type

Methods

receive :: MonadUnliftIO m => UnlimitedBox a -> m (Maybe a)

tryReceive :: MonadUnliftIO m => UnlimitedBox a -> m (Future a)

receiveAfter :: MonadUnliftIO m => UnlimitedBox a -> Int -> m (Maybe a)

newInput :: MonadUnliftIO m => UnlimitedBox a -> m (Input UnlimitedBox a)

IsMessageBox WaitingBox

Defined in UnliftIO.MessageBox.Limited

Associated Types

type Input WaitingBox :: Type -> Type

Methods

receive :: MonadUnliftIO m => WaitingBox a -> m (Maybe a)

tryReceive :: MonadUnliftIO m => WaitingBox a -> m (Future a)

receiveAfter :: MonadUnliftIO m => WaitingBox a -> Int -> m (Maybe a)

newInput :: MonadUnliftIO m => WaitingBox a -> m (Input WaitingBox a)

IsMessageBox NonBlockingBox

Defined in UnliftIO.MessageBox.Limited

Associated Types

type Input NonBlockingBox :: Type -> Type

Methods

receive :: MonadUnliftIO m => NonBlockingBox a -> m (Maybe a)

tryReceive :: MonadUnliftIO m => NonBlockingBox a -> m (Future a)

receiveAfter :: MonadUnliftIO m => NonBlockingBox a -> Int -> m (Maybe a)

newInput :: MonadUnliftIO m => NonBlockingBox a -> m (Input NonBlockingBox a)

IsMessageBox BlockingBox

A blocking instance that invokes receive.

Defined in UnliftIO.MessageBox.Limited

Associated Types

type Input BlockingBox :: Type -> Type

Methods

receive :: MonadUnliftIO m => BlockingBox a -> m (Maybe a)

tryReceive :: MonadUnliftIO m => BlockingBox a -> m (Future a)

receiveAfter :: MonadUnliftIO m => BlockingBox a -> Int -> m (Maybe a)

newInput :: MonadUnliftIO m => BlockingBox a -> m (Input BlockingBox a)

IsMessageBox box => IsMessageBox (CatchAllBox box)

Defined in UnliftIO.MessageBox.CatchAll

Associated Types

type Input (CatchAllBox box) :: Type -> Type

Methods

receive :: MonadUnliftIO m => CatchAllBox box a -> m (Maybe a)

tryReceive :: MonadUnliftIO m => CatchAllBox box a -> m (Future a)

receiveAfter :: MonadUnliftIO m => CatchAllBox box a -> Int -> m (Maybe a)

newInput :: MonadUnliftIO m => CatchAllBox box a -> m (Input (CatchAllBox box) a)

class IsInput input where

A type class for input types. A common interface for delivering messages.

Minimal complete definition

deliver

Methods

deliver :: MonadUnliftIO m => input a -> a -> m Bool

Send a message. Take whatever time it takes. Depending on the implementation, this might be a non-blocking operation. Return if the operation was successful.

NOTE: False may sporadically be returned, especially when there is a lot of load, so please make sure to build your application in such a way, that it anticipates failure.

deliver_ :: MonadUnliftIO m => input a -> a -> m ()

See deliver but with () as return value. If deliver fails, it fails silently.

Instances

IsInput UnlimitedBoxInput

A blocking instance that invokes deliver.

Defined in UnliftIO.MessageBox.Unlimited

Methods

deliver :: MonadUnliftIO m => UnlimitedBoxInput a -> a -> m Bool

deliver_ :: MonadUnliftIO m => UnlimitedBoxInput a -> a -> m ()

IsInput WaitingInput

Defined in UnliftIO.MessageBox.Limited

Methods

deliver :: MonadUnliftIO m => WaitingInput a -> a -> m Bool

deliver_ :: MonadUnliftIO m => WaitingInput a -> a -> m ()

IsInput NonBlockingInput

Defined in UnliftIO.MessageBox.Limited

Methods

deliver :: MonadUnliftIO m => NonBlockingInput a -> a -> m Bool

deliver_ :: MonadUnliftIO m => NonBlockingInput a -> a -> m ()

IsInput BlockingInput

A blocking instance that invokes deliver.

Defined in UnliftIO.MessageBox.Limited

Methods

deliver :: MonadUnliftIO m => BlockingInput a -> a -> m Bool

deliver_ :: MonadUnliftIO m => BlockingInput a -> a -> m ()

IsInput i => IsInput (CatchAllInput i)

Defined in UnliftIO.MessageBox.CatchAll

Methods

deliver :: MonadUnliftIO m => CatchAllInput i a -> a -> m Bool

deliver_ :: MonadUnliftIO m => CatchAllInput i a -> a -> m ()

handleMessage :: (MonadUnliftIO m, IsMessageBox box) => box message -> (message -> m b) -> m (Maybe b)

Receive a message and apply a function to it.