Merge pull request #31 from geekosaur/master

add X.U.Ungrab

CHANGES.md

@@ -11,6 +11,14 @@
   * New constructor `CenteredAt Rational Rational` added for
     `XMonad.Prompt.XPPosition`.
 
+### New Modules
+
+  * `XMonad.Util.Ungrab`
+
+    Release xmonad's keyboard and pointer grabs immediately, so
+    screen grabbers and lock utilities, etc. will work. Replaces
+    the short sleep hackaround.
+
 ## 0.12 (December 14, 2015)
 
 ### Breaking Changes

XMonad/Util/Ungrab.hs

@@ -0,0 +1,43 @@
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  XMonad.Util.Ungrab
+-- Copyright   :  (c) 2016 Brandon S Allbery
+-- License     :  BSD-style (see xmonad/LICENSE)
+--
+-- Maintainer  :  allbery.b@gmail.com
+-- Stability   :  unstable
+-- Portability :  unportable
+--
+-- Allow releasing xmonad's keyboard grab
+--
+-----------------------------------------------------------------------------
+
+module XMonad.Util.Ungrab
+    ( -- * Usage:
+      -- $usage
+      unGrab
+    ) where
+
+import Graphics.X11.Xlib.Extras (currentTime)
+import Graphics.X11.Xlib.Misc (ungrabKeyboard, ungrabPointer)
+import XMonad.Core
+
+-- $usage
+-- Start a keyboard action with this if it is going to run something
+-- that needs to do a keyboard, pointer, or server grab. For example,
+--
+-- > , ((modm .|. controlMask, xK_p), unGrab >> spawn "scrot")
+--
+-- (Other examples are screen lockers and "gksu".)
+-- This avoids needing to insert a pause/sleep before running the
+-- command.
+--
+-- xmonad retains the keyboard grab during key actions because if they
+-- use a Submap, they need the keyboard to be grabbed, and if they had
+-- to assert their own grab then the asynchronous nature of X11 allows
+-- race conditions between xmonad, other clients, and the X server that
+-- would cause keys to sometimes be "leaked" to the focused window.
+
+-- | Release xmonad's keyboard grab, so other grabbers can do their thing.
+unGrab :: X ()
+unGrab = withDisplay $ \d -> io (ungrabKeyboard d currentTime >> ungrabPointer d currentTime)

xmonad-contrib.cabal

@@ -326,6 +326,7 @@ library
                         XMonad.Util.Themes
                         XMonad.Util.Timer
                         XMonad.Util.Types
+                        XMonad.Util.Ungrab
                         XMonad.Util.WindowProperties
                         XMonad.Util.WindowState
                         XMonad.Util.WorkspaceCompare