refactor

1 files changed, 35 insertions, 0 deletions

diff --git a/Utility/ThreadLock.hs b/Utility/ThreadLock.hs
new file mode 100644
index 000000000..4285c0ec5
--- /dev/null
+++ b/Utility/ThreadLock.hs
@@ -0,0 +1,35 @@
+{- locking between threads
+ -
+ - Copyright 2012 Joey Hess <joey@kitenet.net>
+ -
+ - Licensed under the GNU GPL version 3 or higher.
+ -}
+
+module Utility.ThreadLock where
+
+import Common
+
+import System.Posix.Terminal
+import Control.Concurrent.MVar
+import System.Posix.Signals
+
+type Lock = MVar ()
+
+newLock :: IO Lock
+newLock = newMVar ()
+
+{- Runs an action with a lock held, so only one thread at a time can run it. -}
+withLock :: Lock -> IO a -> IO a
+withLock lock = withMVar lock . const
+
+{- Pauses the main thread, letting children run until program termination. -}
+waitForTermination :: IO ()
+waitForTermination = do
+	lock <- newEmptyMVar
+	check softwareTermination lock
+	whenM (queryTerminal stdInput) $
+		check keyboardSignal lock
+	takeMVar lock
+	where
+		check sig lock = void $
+			installHandler sig (CatchOnce $ putMVar lock ()) Nothing