{-# LINE 1 "src/Foreign/R/EventLoop.hsc" #-}
-- |
-- Copyright: (C) 2015 Tweag I/O Limited.
--
-- Bindings for @<R/R_ext/eventloop.h>@, for building event loops.

{-# LANGUAGE CPP #-}
{-# LANGUAGE RecordWildCards #-}

module Foreign.R.EventLoop
  ( InputHandler(..)
  , inputHandlers
  , polledEvents
  , pollingPeriod
  , graphicsPolledEvents
  , graphicsPollingPeriod
  , checkActivity
  , runHandlers
  , addInputHandler
  , removeInputHandler
  ) where

import Control.Applicative
import Foreign (FunPtr, Ptr, Storable(..), castPtr)
import Foreign.C
import Foreign.Marshal.Utils (with)
import System.Posix.Types (Fd(..))
import Prelude -- Silence AMP warning.




-- | R input handler chain. Each input handler points to the next. This view of
-- input handlers is /shallow/, in the sense that the 'Storable' instance only
-- unmarshalls the first element in the chain at any one time. A shallow view
-- allows 'peek' and 'poke' to be inlinable.
data InputHandler = InputHandler
  { -- | The input handler callback.
    InputHandler -> FunPtr (Ptr () -> IO ())
inputHandlerCallback :: FunPtr (Ptr () -> IO ())
    -- | Undocumented and currently unused.
  , InputHandler -> CInt
inputHandlerActivity :: CInt
    -- | Whether this input handler is activated or deactivated.
  , InputHandler -> CInt
inputHandlerActive :: CInt
    -- | The file descriptor ahssociated with this handler.
  , InputHandler -> Fd
inputHandlerFD :: Fd
    -- | Callbacks can optionally be passed in arbitrary data.
  , InputHandler -> Ptr ()
inputHandlerUserData :: Ptr ()
    -- | The next input handler in the chain.
  , InputHandler -> Ptr InputHandler
inputHandlerNext :: Ptr InputHandler
  } deriving (InputHandler -> InputHandler -> Bool
(InputHandler -> InputHandler -> Bool)
-> (InputHandler -> InputHandler -> Bool) -> Eq InputHandler
forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
/= :: InputHandler -> InputHandler -> Bool
$c/= :: InputHandler -> InputHandler -> Bool
== :: InputHandler -> InputHandler -> Bool
$c== :: InputHandler -> InputHandler -> Bool
Eq, Int -> InputHandler -> ShowS
[InputHandler] -> ShowS
InputHandler -> String
(Int -> InputHandler -> ShowS)
-> (InputHandler -> String)
-> ([InputHandler] -> ShowS)
-> Show InputHandler
forall a.
(Int -> a -> ShowS) -> (a -> String) -> ([a] -> ShowS) -> Show a
showList :: [InputHandler] -> ShowS
$cshowList :: [InputHandler] -> ShowS
show :: InputHandler -> String
$cshow :: InputHandler -> String
showsPrec :: Int -> InputHandler -> ShowS
$cshowsPrec :: Int -> InputHandler -> ShowS
Show)

instance Storable InputHandler where
  sizeOf :: InputHandler -> Int
sizeOf _ = (40)
{-# LINE 53 "src/Foreign/R/EventLoop.hsc" #-}
  alignment _ = 8
{-# LINE 54 "src/Foreign/R/EventLoop.hsc" #-}
  peek hptr = InputHandler <$>
      (\hsc_ptr -> peekByteOff hsc_ptr 8) hptr <*>
{-# LINE 56 "src/Foreign/R/EventLoop.hsc" #-}
      (\hsc_ptr -> peekByteOff hsc_ptr 0) hptr <*>
{-# LINE 57 "src/Foreign/R/EventLoop.hsc" #-}
      (\hsc_ptr -> peekByteOff hsc_ptr 24) hptr <*>
{-# LINE 58 "src/Foreign/R/EventLoop.hsc" #-}
      (Fd <$> (\hsc_ptr -> peekByteOff hsc_ptr 4) hptr) <*>
{-# LINE 59 "src/Foreign/R/EventLoop.hsc" #-}
      (\hsc_ptr -> peekByteOff hsc_ptr 32) hptr <*>
{-# LINE 60 "src/Foreign/R/EventLoop.hsc" #-}
      (castPtr <$> (\hsc_ptr -> peekByteOff hsc_ptr 16) hptr)
{-# LINE 61 "src/Foreign/R/EventLoop.hsc" #-}
  poke hptr InputHandler{..} = do
    (\hsc_ptr -> pokeByteOff hsc_ptr 8) hptr inputHandlerCallback
{-# LINE 63 "src/Foreign/R/EventLoop.hsc" #-}
    (\hsc_ptr -> pokeByteOff hsc_ptr 0) hptr inputHandlerActivity
{-# LINE 64 "src/Foreign/R/EventLoop.hsc" #-}
    (\hsc_ptr -> pokeByteOff hsc_ptr 24) hptr inputHandlerActive
{-# LINE 65 "src/Foreign/R/EventLoop.hsc" #-}
    (\hsc_ptr -> pokeByteOff hsc_ptr 4) hptr (case inputHandlerFD of Fd fd -> fd)
{-# LINE 66 "src/Foreign/R/EventLoop.hsc" #-}
    (\hsc_ptr -> pokeByteOff hsc_ptr 32) hptr inputHandlerUserData
{-# LINE 67 "src/Foreign/R/EventLoop.hsc" #-}
    (\hsc_ptr -> pokeByteOff hsc_ptr 16) hptr (castPtr inputHandlerNext)
{-# LINE 68 "src/Foreign/R/EventLoop.hsc" #-}

-- | @R_PolledEvents@ global variable.
foreign import ccall "&R_PolledEvents" polledEvents :: Ptr (FunPtr (IO ()))

-- | @R_wait_usec@ global variable.
foreign import ccall "&R_wait_usec" pollingPeriod :: Ptr CInt

-- | @R_PolledEvents@ global variable.
foreign import ccall "&Rg_PolledEvents" graphicsPolledEvents :: Ptr (FunPtr (IO ()))

-- | @R_wait_usec@ global variable.
foreign import ccall "&Rg_wait_usec" graphicsPollingPeriod :: Ptr CInt

-- | Input handlers used in event loops.
foreign import ccall "&R_InputHandlers" inputHandlers :: Ptr (Ptr InputHandler)

data FdSet

foreign import ccall unsafe "R_checkActivity" checkActivity
  :: CInt
  -> CInt
  -> IO (Ptr FdSet)

foreign import ccall "R_runHandlers" runHandlers
  :: Ptr InputHandler
  -> Ptr FdSet
  -> IO ()

foreign import ccall "addInputHandler" addInputHandler_
  :: Ptr InputHandler
  -> Fd
  -> FunPtr (Ptr () -> IO ())
  -> CInt
  -> IO (Ptr InputHandler)

-- | Create and register a new 'InputHandler'. The given file descriptor should
-- be open in non-blocking read mode. Make sure to dispose of the callback using
-- 'freeHaskellFunPtr' after calling 'removeInputHandler' where appropriate.
addInputHandler
  :: Ptr InputHandler
  -> Fd
  -> FunPtr (Ptr () -> IO ())
  -> Int
  -> IO (Ptr InputHandler)
addInputHandler :: Ptr InputHandler
-> Fd -> FunPtr (Ptr () -> IO ()) -> Int -> IO (Ptr InputHandler)
addInputHandler ihptr :: Ptr InputHandler
ihptr fd :: Fd
fd f :: FunPtr (Ptr () -> IO ())
f activity :: Int
activity = do
    Ptr InputHandler
-> Fd -> FunPtr (Ptr () -> IO ()) -> CInt -> IO (Ptr InputHandler)
addInputHandler_ Ptr InputHandler
ihptr Fd
fd FunPtr (Ptr () -> IO ())
f (Int -> CInt
forall a b. (Integral a, Num b) => a -> b
fromIntegral Int
activity)

foreign import ccall "removeInputHandler" removeInputHandler_
  :: Ptr (Ptr InputHandler)
  -> Ptr InputHandler
  -> IO CInt

-- | Remove an input handler from an input handler chain. Returns 'True' if the
-- handler was successfully removed, 'False' otherwise.
removeInputHandler :: Ptr InputHandler -> Ptr InputHandler -> IO Bool
removeInputHandler :: Ptr InputHandler -> Ptr InputHandler -> IO Bool
removeInputHandler handlers :: Ptr InputHandler
handlers ih :: Ptr InputHandler
ih =
    Ptr InputHandler -> (Ptr (Ptr InputHandler) -> IO Bool) -> IO Bool
forall a b. Storable a => a -> (Ptr a -> IO b) -> IO b
with Ptr InputHandler
handlers ((Ptr (Ptr InputHandler) -> IO Bool) -> IO Bool)
-> (Ptr (Ptr InputHandler) -> IO Bool) -> IO Bool
forall a b. (a -> b) -> a -> b
$ \handlersptr :: Ptr (Ptr InputHandler)
handlersptr -> do
      CInt
rc <- Ptr (Ptr InputHandler) -> Ptr InputHandler -> IO CInt
removeInputHandler_ Ptr (Ptr InputHandler)
handlersptr Ptr InputHandler
ih
      case CInt
rc of
        0 -> Bool -> IO Bool
forall (m :: * -> *) a. Monad m => a -> m a
return (Bool -> IO Bool) -> Bool -> IO Bool
forall a b. (a -> b) -> a -> b
$ Bool
False
        1 -> Bool -> IO Bool
forall (m :: * -> *) a. Monad m => a -> m a
return (Bool -> IO Bool) -> Bool -> IO Bool
forall a b. (a -> b) -> a -> b
$ Bool
True
        _ -> String -> IO Bool
forall a. HasCallStack => String -> a
error "removeInputHandler: unexpected result."