New --time-limit option, makes long git-annex commands stop after a specified amount of time.

Utility/HumanTime.hs

@@ -0,0 +1,26 @@
+{- Time for humans.
+ -
+ - Copyright 2012 Joey Hess <joey@kitenet.net>
+ -
+ - Licensed under the GNU GPL version 3 or higher.
+ -}
+
+module Utility.HumanTime where
+
+import Utility.PartialPrelude
+
+import Data.Time.Clock.POSIX (POSIXTime)
+
+{- Parses a human-input time duration, of the form "5h" or "1m". -}
+parseDuration :: String -> Maybe POSIXTime
+parseDuration s = do
+	num <- readish s :: Maybe Integer
+	units <- findUnits =<< lastMaybe s
+	return $ fromIntegral num * units
+	where
+		findUnits 's' = Just 1
+		findUnits 'm' = Just 60
+		findUnits 'h' = Just $ 60 * 60
+		findUnits 'd' = Just $ 60 * 60 * 24
+		findUnits 'y' = Just $ 60 * 60 * 24 * 365
+		findUnits _ = Nothing