BoundedQueue.hs

-- Copyright (c) 2013-2014 PivotCloud, Inc.
--
-- Control.Concurrent.STM.BoundedQueue
--
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-- Licensed under the Apache License, Version 2.0 (the "License"); you may
-- not use this file except in compliance with the License. You may obtain a
-- copy of the License at http://www.apache.org/licenses/LICENSE-2.0
--
-- Unless required by applicable law or agreed to in writing, software
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-- WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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--

{-# LANGUAGE Safe #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE UnicodeSyntax #-}

module Control.Concurrent.STM.BoundedQueue
( BoundedQueue(..)
) where

import Control.Applicative
import Control.Concurrent.STM
import Control.Concurrent.STM.TBMQueue
import Control.Concurrent.STM.Queue

class Queue q ⇒ BoundedQueue q where
  tryWriteQueue
    ∷ q α
    → α
    → STM (QueueValue q Bool)

  isFullQueue
    ∷ q α
    → STM Bool

instance BoundedQueue TBQueue where
  tryWriteQueue q x = do
   True <$ writeTBQueue q x
     <|> pure False

  isFullQueue = isFullTBQueue

instance BoundedQueue TBMQueue where
  tryWriteQueue = tryWriteTBMQueue
  isFullQueue = isFullTBMQueue