find: Support --print0

It would be nice if command-specific options were supported. The first
difficulty is that which command is being called is not known until after
getopt; but that could be worked around by finding the first non-dashed
parameter. Storing the settings without putting them in the annex monad is
the next difficulty; it could perhaps be handled by making the seek stage
pass applicable settings into the start stage (and from there on to perform
as needed). But that still leaves a problem, what data type to use to
represent the options between getopt and seek?

Annex.hs

@@ -60,6 +60,7 @@ data AnnexState = AnnexState
 	, force :: Bool
 	, fast :: Bool
 	, auto :: Bool
+	, print0 :: Bool
 	, branchstate :: BranchState
 	, catfilehandle :: Maybe CatFileHandle
 	, forcebackend :: Maybe String
@@ -82,6 +83,7 @@ newState gitrepo = AnnexState
 	, force = False
 	, fast = False
 	, auto = False
+	, print0 = False
 	, branchstate = startBranchState
 	, catfilehandle = Nothing
 	, forcebackend = Nothing

Command/Find.hs

@@ -11,6 +11,7 @@ import Common.Annex
 import Command
 import Annex.Content
 import Limit
+import qualified Annex
 
 def :: [Command]
 def = [command "find" paramPaths seek "lists available files"]
@@ -22,6 +23,9 @@ start :: FilePath -> (Key, Backend Annex) -> CommandStart
 start file (key, _) = do
 	-- only files inAnnex are shown, unless the user has requested
 	-- others via a limit
-	whenM (liftM2 (||) (inAnnex key) limited) $
-		liftIO $ putStrLn file
+	whenM (liftM2 (||) (inAnnex key) limited) $ do
+		print0 <- Annex.getState Annex.print0
+		if print0
+			then liftIO $ putStr (file ++ "\0")
+			else liftIO $ putStrLn file
 	stop

GitAnnex.hs

@@ -103,6 +103,8 @@ options = commonOptions ++
 		"override trust setting to untrusted"
 	, Option ['c'] ["config"] (ReqArg setgitconfig "NAME=VALUE")
 		"override git configuration setting"
+	, Option [] ["print0"] (NoArg (setprint0 True))
+		"terminate filename with null"
 	, Option ['x'] ["exclude"] (ReqArg Limit.addExclude paramGlob)
 		"skip files matching the glob pattern"
 	, Option ['i'] ["in"] (ReqArg Limit.addIn paramRemote)
@@ -114,6 +116,7 @@ options = commonOptions ++
 		setto v = Annex.changeState $ \s -> s { Annex.toremote = Just v }
 		setfrom v = Annex.changeState $ \s -> s { Annex.fromremote = Just v }
 		setnumcopies v = Annex.changeState $ \s -> s {Annex.forcenumcopies = readMaybe v }
+		setprint0 v = Annex.changeState $ \s -> s { Annex.print0 = v }
 		setgitconfig :: String -> Annex ()
 		setgitconfig v = do
 			newg <- inRepo $ Git.configStore v

debian/changelog

@@ -19,6 +19,7 @@ git-annex (3.20111112) UNRELEASED; urgency=low
   * migrate: Don't fall over a stale temp file.
   * Avoid excessive escaping for rsync special remotes that are not accessed
     over ssh.
+  * find: Support --print0
 
  -- Joey Hess <joeyh@debian.org>  Sat, 12 Nov 2011 14:50:21 -0400
 

doc/forum/--print0_option_as_in___34__find__34__.mdwn

@@ -1,3 +1,5 @@
 It would be nice if git annex find supported a --print0 option as GNU
 find does.  That way, file names that are printed could be piped to
 xargs even if they have spaces. 
+
+> Done. --[[Joey]] 

doc/git-annex.mdwn

@@ -232,6 +232,9 @@ subdirectories).
   With no parameters, defaults to finding all files in the current directory
   and its subdirectories.
 
+  To output filenames terminated with nulls, for use with xargs -0,
+  specify --print0.
+
 * whereis [path ...]
 
   Displays a list of repositories known to contain the content of the