findref: New command, like find but shows files in a specified git ref.

CmdLine/GitAnnex.hs

@@ -49,6 +49,7 @@ import qualified Command.Unlock
 import qualified Command.Lock
 import qualified Command.PreCommit
 import qualified Command.Find
+import qualified Command.FindRef
 import qualified Command.Whereis
 import qualified Command.List
 import qualified Command.Log
@@ -158,6 +159,7 @@ cmds = concat
 	, Command.DropUnused.def
 	, Command.AddUnused.def
 	, Command.Find.def
+	, Command.FindRef.def
 	, Command.Whereis.def
 	, Command.List.def
 	, Command.Log.def

CmdLine/Seek.hs

@@ -19,6 +19,8 @@ import qualified Annex
 import qualified Git
 import qualified Git.Command
 import qualified Git.LsFiles as LsFiles
+import qualified Git.LsTree as LsTree
+import Git.FilePath
 import qualified Limit
 import CmdLine.Option
 import CmdLine.Action
@@ -49,6 +51,20 @@ withFilesNotInGit skipdotfiles a params
 	go l = seekActions $ prepFiltered a $
 		return $ concat $ segmentPaths params l
 
+withFilesInRefs :: (FilePath -> Key -> CommandStart) -> CommandSeek
+withFilesInRefs a = mapM_ go
+  where
+	go r = do	
+		matcher <- Limit.getMatcher
+		l <- inRepo $ LsTree.lsTree (Git.Ref r)
+		forM_ l $ \i -> do
+			let f = getTopFilePath $ LsTree.file i
+			v <- catKey (Git.Ref $ LsTree.sha i) (LsTree.mode i)
+			case v of
+				Nothing -> noop
+				Just k -> whenM (matcher $ MatchingKey k) $
+					void $ commandAction $ a f k
+
 withPathContents :: ((FilePath, FilePath) -> CommandStart) -> CommandSeek
 withPathContents a params = seekActions $ 
 	map a . concat <$> liftIO (mapM get params)

CmdLine/Usage.hs

@@ -93,6 +93,8 @@ paramFormat :: String
 paramFormat = "FORMAT"
 paramFile :: String
 paramFile = "FILE"
+paramRef :: String
+paramRef = "REF"
 paramGroup :: String
 paramGroup = "GROUP"
 paramExpression :: String