    {-# LANGUAGE CPP #-}
    {- |
    Module      :  XMonad.Util.XSelection
    Description :  A module for accessing and manipulating the primary selection.
    Copyright   :  (C) 2007 Andrea Rossato, Matthew Sackman
    License     :  BSD3

    Maintainer  : Gwern Branwen <gwern0@gmail.com>
    Stability   :  unstable
    Portability :  unportable

    A module for accessing and manipulating X Window's mouse selection (the buffer used in copy and pasting).
    'getSelection' is an adaptation of Hxsel.hs and Hxput.hs from the XMonad-utils, available:

    > $ darcs get <http://gorgias.mine.nu/repos/xmonad-utils>
    -}

    module XMonad.Util.XSelection (  -- * Usage
                                     -- $usage
                                     getSelection,
                                     promptSelection,
                                     safePromptSelection,
                                     transformPromptSelection,
                                     transformSafePromptSelection) where

    import Control.Exception as E (catch,SomeException(..))
    import XMonad
    import XMonad.Util.Run (safeSpawn, unsafeSpawn)

    import Codec.Binary.UTF8.String (decode)

    {- $usage
       Add @import XMonad.Util.XSelection@ to the top of Config.hs
       Then make use of getSelection or promptSelection as needed; if
       one wanted to run Firefox with the selection as an argument (perhaps
       the selection string is an URL you just highlighted), then one could add
       to the xmonad.hs a line like thus:

       > , ((modm .|. shiftMask, xK_b), promptSelection "firefox")

       Future improvements for XSelection:

       * More elaborate functionality: Emacs' registers are nice; if you
          don't know what they are, see <http://www.gnu.org/software/emacs/manual/html_node/emacs/Registers.html#Registers> -}

    -- | Returns a String corresponding to the current mouse selection in X;
    --   if there is none, an empty string is returned.
    --
    -- WARNING: this function is fundamentally implemented incorrectly and may, among other possible failure modes,
    -- deadlock or crash. For details, see <http://code.google.com/p/xmonad/issues/detail?id=573>.
    -- (These errors are generally very rare in practice, but still exist.)
    getSelection :: MonadIO m => m String
    getSelection :: forall (m :: * -> *). MonadIO m => m String
    getSelection = IO String -> m String
    forall (m :: * -> *) a. MonadIO m => IO a -> m a
    io (IO String -> m String) -> IO String -> m String
    forall a b. (a -> b) -> a -> b
    $ do
      dpy <- String -> IO Display
    openDisplay String
    ""
      let dflt = Display -> Dimension
    defaultScreen Display
    dpy
      rootw  <- rootWindow dpy dflt
      win <- createSimpleWindow dpy rootw 0 0 1 1 0 0 0
      p <- internAtom dpy "PRIMARY" True
      ty <- E.catch
                   (E.catch
                         (internAtom dpy "UTF8_STRING" False)
                         (\(E.SomeException e
    _) -> Display -> String -> Bool -> IO Pixel
    internAtom Display
    dpy String
    "COMPOUND_TEXT" Bool
    False))
                 (\(E.SomeException e
    _) -> Display -> String -> Bool -> IO Pixel
    internAtom Display
    dpy String
    "sTring" Bool
    False)
      clp <- internAtom dpy "BLITZ_SEL_STRING" False
      xConvertSelection dpy p ty clp win currentTime
      allocaXEvent $ \XEventPtr
    e -> do
        Display -> XEventPtr -> IO ()
    nextEvent Display
    dpy XEventPtr
    e
        ev <- XEventPtr -> IO Event
    getEvent XEventPtr
    e
        result <- if ev_event_type ev == selectionNotify
                     then do res <- getWindowProperty8 dpy clp win
                             return $ decode . maybe [] (map fromIntegral) $ res
                     else destroyWindow dpy win >> return ""
        closeDisplay dpy
        return result

    {- | A wrapper around 'getSelection'. Makes it convenient to run a program with the current selection as an argument.
      This is convenient for handling URLs, in particular. For example, in your Config.hs you could bind a key to
             @promptSelection \"firefox\"@;
      this would allow you to highlight a URL string and then immediately open it up in Firefox.

      'promptSelection' passes strings through the system shell, \/bin\/sh; if you do not wish your selected text
      to be interpreted or mangled by the shell, use 'safePromptSelection'. safePromptSelection will bypass the
      shell using 'safeSpawn' from "XMonad.Util.Run"; see its documentation for more
      details on the advantages and disadvantages of using safeSpawn. -}
    promptSelection, safePromptSelection, unsafePromptSelection :: String -> X ()
    promptSelection :: String -> X ()
    promptSelection = String -> X ()
    unsafePromptSelection
    safePromptSelection :: String -> X ()
    safePromptSelection String
    app = String -> [String] -> X ()
    forall (m :: * -> *). MonadIO m => String -> [String] -> m ()
    safeSpawn String
    app ([String] -> X ()) -> (String -> [String]) -> String -> X ()
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . String -> [String]
    forall a. a -> [a]
    forall (m :: * -> *) a. Monad m => a -> m a
    return (String -> X ()) -> X String -> X ()
    forall (m :: * -> *) a b. Monad m => (a -> m b) -> m a -> m b
    =<< X String
    forall (m :: * -> *). MonadIO m => m String
    getSelection
    unsafePromptSelection :: String -> X ()
    unsafePromptSelection String
    app = String -> X ()
    forall (m :: * -> *). MonadIO m => String -> m ()
    unsafeSpawn (String -> X ()) -> (String -> String) -> String -> X ()
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . (\String
    x -> String
    app String -> String -> String
    forall a. [a] -> [a] -> [a]
    ++ String
    " " String -> String -> String
    forall a. [a] -> [a] -> [a]
    ++ String
    x) (String -> X ()) -> X String -> X ()
    forall (m :: * -> *) a b. Monad m => (a -> m b) -> m a -> m b
    =<< X String
    forall (m :: * -> *). MonadIO m => m String
    getSelection

    {- | A wrapper around 'promptSelection' and its safe variant. They take two parameters, the
         first is a function that transforms strings, and the second is the application to run.
         The transformer essentially transforms the selection in X.
         One example is to wrap code, such as a command line action copied out of the browser
         to be run as @"sudo" ++ cmd@ or @"su - -c \""++ cmd ++"\""@. -}
    transformPromptSelection, transformSafePromptSelection :: (String -> String) -> String -> X ()
    transformPromptSelection :: (String -> String) -> String -> X ()
    transformPromptSelection String -> String
    f String
    app = (String -> [String] -> X ()
    forall (m :: * -> *). MonadIO m => String -> [String] -> m ()
    safeSpawn String
    app ([String] -> X ()) -> (String -> [String]) -> String -> X ()
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . String -> [String]
    forall a. a -> [a]
    forall (m :: * -> *) a. Monad m => a -> m a
    return (String -> [String]) -> (String -> String) -> String -> [String]
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . String -> String
    f) (String -> X ()) -> X String -> X ()
    forall (m :: * -> *) a b. Monad m => (a -> m b) -> m a -> m b
    =<< X String
    forall (m :: * -> *). MonadIO m => m String
    getSelection
    transformSafePromptSelection :: (String -> String) -> String -> X ()
    transformSafePromptSelection String -> String
    f String
    app = String -> X ()
    forall (m :: * -> *). MonadIO m => String -> m ()
    unsafeSpawn (String -> X ()) -> (String -> String) -> String -> X ()
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . (\String
    x -> String
    app String -> String -> String
    forall a. [a] -> [a] -> [a]
    ++ String
    " " String -> String -> String
    forall a. [a] -> [a] -> [a]
    ++ String
    x) (String -> String) -> (String -> String) -> String -> String
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . String -> String
    f (String -> X ()) -> X String -> X ()
    forall (m :: * -> *) a b. Monad m => (a -> m b) -> m a -> m b
    =<< X String
    forall (m :: * -> *). MonadIO m => m String
    getSelection