make the standalone OSX app automatically install itself when run

Assistant/Install.hs

@@ -0,0 +1,45 @@
+{- Assistant installation
+ -
+ - Copyright 2012 Joey Hess <joey@kitenet.net>
+ -
+ - Licensed under the GNU GPL version 3 or higher.
+ -}
+
+module Assistant.Install where
+
+import Locations.UserConfig
+import Utility.OSX
+import Utility.Path
+
+import System.Posix.Env
+import System.Directory
+
+{- The OSX git-annex.app does not have an installation process.
+ - So when it's run, it needs to set up autostarting of the assistant
+ - daemon, as well as writing the programFile.
+ -
+ - Note that this is done every time it's started, so if the user moves
+ - it around, the paths this sets up won't break.
+ -}
+ensureInstalled :: IO ()
+ensureInstalled = do
+	e <- getEnv "OSX_GIT_ANNEX_APP_PROGRAM"
+	case e of
+		Nothing -> return ()
+		Just program -> do
+			programfile <- programFile
+			createDirectoryIfMissing True (parentDir programfile)
+			writeFile programfile program
+
+			autostartfile <- userAutoStart autoStartLabel
+			installAutoStart program autostartfile
+
+{- Installs an autostart plist file for OSX. -}
+installAutoStart :: FilePath -> FilePath -> IO ()
+installAutoStart command file = do
+	createDirectoryIfMissing True (parentDir file)
+	writeFile file $ genOSXAutoStartFile autoStartLabel command
+		["assistant", "--autostart"]
+
+autoStartLabel :: String
+autoStartLabel = "com.branchable.git-annex.assistant"