Fourmolu

auto-update/Control/AutoUpdate.hs

@@ -1,4 +1,5 @@
 {-# LANGUAGE CPP #-}
+
 -- | In a multithreaded environment, running actions on a regularly scheduled
 -- background thread can dramatically improve performance.
 -- For example, web servers need to return the current time with each HTTP response.
@@ -29,39 +30,52 @@
 --
 -- For more examples, <http://www.yesodweb.com/blog/2014/08/announcing-auto-update see the blog post introducing this library>.
 module Control.AutoUpdate (
-      -- * Type
-      UpdateSettings
-    , defaultUpdateSettings
-      -- * Accessors
-    , updateAction
-    , updateFreq
-    , updateSpawnThreshold
-      -- * Creation
-    , mkAutoUpdate
-    , mkAutoUpdateWithModify
-    ) where
+    -- * Type
+    UpdateSettings,
+    defaultUpdateSettings,
+
+    -- * Accessors
+    updateAction,
+    updateFreq,
+    updateSpawnThreshold,
+
+    -- * Creation
+    mkAutoUpdate,
+    mkAutoUpdateWithModify,
+) where
 
 #if __GLASGOW_HASKELL__ < 709
 import           Control.Applicative     ((<*>))
 #endif
-import           Control.Concurrent      (forkIO, threadDelay)
-import           Control.Concurrent.MVar (newEmptyMVar, putMVar, readMVar,
-                                          takeMVar, tryPutMVar)
-import           Control.Exception       (SomeException, catch, mask_, throw,
-                                          try)
-import           Control.Monad           (void)
-import           Data.IORef              (newIORef, readIORef, writeIORef)
-import           Data.Maybe              (fromMaybe)
+import Control.Concurrent (forkIO, threadDelay)
+import Control.Concurrent.MVar (
+    newEmptyMVar,
+    putMVar,
+    readMVar,
+    takeMVar,
+    tryPutMVar,
+ )
+import Control.Exception (
+    SomeException,
+    catch,
+    mask_,
+    throw,
+    try,
+ )
+import Control.Monad (void)
+import Data.IORef (newIORef, readIORef, writeIORef)
+import Data.Maybe (fromMaybe)
 
 -- | Default value for creating an 'UpdateSettings'.
 --
 -- @since 0.1.0
 defaultUpdateSettings :: UpdateSettings ()
-defaultUpdateSettings = UpdateSettings
-    { updateFreq = 1000000
-    , updateSpawnThreshold = 3
-    , updateAction = return ()
-    }
+defaultUpdateSettings =
+    UpdateSettings
+        { updateFreq = 1000000
+        , updateSpawnThreshold = 3
+        , updateAction = return ()
+        }
 
 -- | Settings to control how values are updated.
 --
@@ -74,7 +88,7 @@ defaultUpdateSettings = UpdateSettings
 --
 -- @since 0.1.0
 data UpdateSettings a = UpdateSettings
-    { updateFreq           :: Int
+    { updateFreq :: Int
     -- ^ Microseconds between update calls. Same considerations as
     -- 'threadDelay' apply.
     --
@@ -91,7 +105,7 @@ data UpdateSettings a = UpdateSettings
     -- Default: 3
     --
     -- @since 0.1.0
-    , updateAction         :: IO a
+    , updateAction :: IO a
     -- ^ Action to be performed to get the current value.
     --
     -- Default: does nothing.
@@ -137,12 +151,16 @@ mkAutoUpdateHelper us updateActionModify = do
     let fillRefOnExit f = do
             eres <- try f
             case eres of
-                Left e -> writeIORef currRef $ error $
-                    "Control.AutoUpdate.mkAutoUpdate: worker thread exited with exception: "
-                    ++ show (e :: SomeException)
-                Right () -> writeIORef currRef $ error $
-                    "Control.AutoUpdate.mkAutoUpdate: worker thread exited normally, "
-                    ++ "which should be impossible due to usage of infinite loop"
+                Left e ->
+                    writeIORef currRef $
+                        error $
+                            "Control.AutoUpdate.mkAutoUpdate: worker thread exited with exception: "
+                                ++ show (e :: SomeException)
+                Right () ->
+                    writeIORef currRef $
+                        error $
+                            "Control.AutoUpdate.mkAutoUpdate: worker thread exited normally, "
+                                ++ "which should be impossible due to usage of infinite loop"
 
     -- fork the worker thread immediately. Note that we mask async exceptions,
     -- but *not* in an uninterruptible manner. This will allow a

auto-update/Control/AutoUpdate/Util.hs

@@ -1,7 +1,8 @@
 {-# LANGUAGE CPP #-}
-module Control.AutoUpdate.Util
-    ( atomicModifyIORef'
-    ) where
+
+module Control.AutoUpdate.Util (
+    atomicModifyIORef',
+) where
 
 #ifndef MIN_VERSION_base
 #define MIN_VERSION_base(x,y,z) 1

auto-update/Control/Debounce.hs

@@ -23,37 +23,40 @@
 -- See the fast-logger package ("System.Log.FastLogger") for real-world usage.
 --
 -- @since 0.1.2
-module Control.Debounce
-    ( -- * Type
-      DI.DebounceSettings
-    , defaultDebounceSettings
-      -- * Accessors
-    , DI.debounceFreq
-    , DI.debounceAction
-    , DI.debounceEdge
-    , DI.leadingEdge
-    , DI.trailingEdge
-      -- * Creation
-    , mkDebounce
-    ) where
+module Control.Debounce (
+    -- * Type
+    DI.DebounceSettings,
+    defaultDebounceSettings,
 
-import           Control.Concurrent      (newEmptyMVar, threadDelay)
+    -- * Accessors
+    DI.debounceFreq,
+    DI.debounceAction,
+    DI.debounceEdge,
+    DI.leadingEdge,
+    DI.trailingEdge,
+
+    -- * Creation
+    mkDebounce,
+) where
+
+import Control.Concurrent (newEmptyMVar, threadDelay)
 import qualified Control.Debounce.Internal as DI
 
 -- | Default value for creating a 'DebounceSettings'.
 --
 -- @since 0.1.2
 defaultDebounceSettings :: DI.DebounceSettings
-defaultDebounceSettings = DI.DebounceSettings
-    { DI.debounceFreq = 1000000
-    , DI.debounceAction = return ()
-    , DI.debounceEdge = DI.leadingEdge
-    }
+defaultDebounceSettings =
+    DI.DebounceSettings
+        { DI.debounceFreq = 1000000
+        , DI.debounceAction = return ()
+        , DI.debounceEdge = DI.leadingEdge
+        }
 
 -- | Generate an action which will trigger the debounced action to be performed.
 --
 -- @since 0.1.2
 mkDebounce :: DI.DebounceSettings -> IO (IO ())
 mkDebounce settings = do
-  baton <- newEmptyMVar
-  DI.mkDebounceInternal baton threadDelay settings
+    baton <- newEmptyMVar
+    DI.mkDebounceInternal baton threadDelay settings

auto-update/Control/Debounce/Internal.hs

@@ -2,17 +2,22 @@
 
 -- | Unstable API which exposes internals for testing.
 module Control.Debounce.Internal (
-  DebounceSettings(..)
-  , DebounceEdge(..)
-  , leadingEdge
-  , trailingEdge
-  , mkDebounceInternal
-  ) where
+    DebounceSettings (..),
+    DebounceEdge (..),
+    leadingEdge,
+    trailingEdge,
+    mkDebounceInternal,
+) where
 
-import           Control.Concurrent      (forkIO)
-import           Control.Concurrent.MVar (takeMVar, tryPutMVar, tryTakeMVar, MVar)
-import           Control.Exception       (SomeException, handle, mask_)
-import           Control.Monad           (forever, void)
+import Control.Concurrent (forkIO)
+import Control.Concurrent.MVar (
+    MVar,
+    takeMVar,
+    tryPutMVar,
+    tryTakeMVar,
+ )
+import Control.Exception (SomeException, handle, mask_)
+import Control.Monad (forever, void)
 
 -- | Settings to control how debouncing should work.
 --
@@ -25,7 +30,7 @@ import           Control.Monad           (forever, void)
 --
 -- @since 0.1.2
 data DebounceSettings = DebounceSettings
-    { debounceFreq   :: Int
+    { debounceFreq :: Int
     -- ^ Length of the debounce timeout period in microseconds.
     --
     -- Default: 1 second (1000000)
@@ -52,16 +57,15 @@ data DebounceSettings = DebounceSettings
 -- edge of the timeout.
 --
 -- @since 0.1.6
-data DebounceEdge =
-  Leading
-  -- ^ Perform the action immediately, and then begin a cooldown period.
-  -- If the trigger happens again during the cooldown, wait until the end of the cooldown
-  -- and then perform the action again, then enter a new cooldown period.
-  | Trailing
-  -- ^ Start a cooldown period and perform the action when the period ends. If another trigger
-  -- happens during the cooldown, it has no effect.
-  deriving (Show, Eq)
-
+data DebounceEdge
+    = -- | Perform the action immediately, and then begin a cooldown period.
+      -- If the trigger happens again during the cooldown, wait until the end of the cooldown
+      -- and then perform the action again, then enter a new cooldown period.
+      Leading
+    | -- | Start a cooldown period and perform the action when the period ends. If another trigger
+      -- happens during the cooldown, it has no effect.
+      Trailing
+    deriving (Show, Eq)
 
 -- | Perform the action immediately, and then begin a cooldown period.
 -- If the trigger happens again during the cooldown, wait until the end of the cooldown
@@ -78,19 +82,20 @@ leadingEdge = Leading
 trailingEdge :: DebounceEdge
 trailingEdge = Trailing
 
-mkDebounceInternal :: MVar () -> (Int -> IO ()) -> DebounceSettings -> IO (IO ())
+mkDebounceInternal
+    :: MVar () -> (Int -> IO ()) -> DebounceSettings -> IO (IO ())
 mkDebounceInternal baton delayFn (DebounceSettings freq action edge) = do
     mask_ $ void $ forkIO $ forever $ do
         takeMVar baton
         case edge of
-          Leading -> do
-            ignoreExc action
-            delayFn freq
-          Trailing -> do
-            delayFn freq
-            -- Empty the baton of any other activations during the interval
-            void $ tryTakeMVar baton
-            ignoreExc action
+            Leading -> do
+                ignoreExc action
+                delayFn freq
+            Trailing -> do
+                delayFn freq
+                -- Empty the baton of any other activations during the interval
+                void $ tryTakeMVar baton
+                ignoreExc action
 
     return $ void $ tryPutMVar baton ()