From 7d5b25515ce8e22116f95e3679953ea956b4f04f Mon Sep 17 00:00:00 2001
From: Joey Hess <joey@kitenet.net>
Date: Sun, 15 Dec 2013 14:02:23 -0400
Subject: [PATCH] Add plumbing-level lookupkey command.

---
 Annex/CatFile.hs     |  2 +-
 Command/LookupKey.hs | 26 ++++++++++++++++++++++++++
 GitAnnex.hs          |  2 ++
 debian/changelog     |  1 +
 doc/git-annex.mdwn   |  7 +++++++
 5 files changed, 37 insertions(+), 1 deletion(-)
 create mode 100644 Command/LookupKey.hs

diff --git a/Annex/CatFile.hs b/Annex/CatFile.hs
index 812d032c6a..54a4d10991 100644
--- a/Annex/CatFile.hs
+++ b/Annex/CatFile.hs
@@ -119,7 +119,7 @@ catKeyChecked needhead ref@(Ref r) =
  - For command-line git-annex use, that doesn't matter. It's perfectly
  - reasonable for things staged in the index after the currently running
  - git-annex process to not be noticed by it. However, we do want to see
- - what's in the index, since it may have uncommitted changes not in HEAD>
+ - what's in the index, since it may have uncommitted changes not in HEAD
  -
  - For the assistant, this is much more of a problem, since it commits
  - files and then needs to be able to immediately look up their keys.
diff --git a/Command/LookupKey.hs b/Command/LookupKey.hs
new file mode 100644
index 0000000000..7964213fe3
--- /dev/null
+++ b/Command/LookupKey.hs
@@ -0,0 +1,26 @@
+{- git-annex command
+ -
+ - Copyright 2013 Joey Hess <joey@kitenet.net>
+ -
+ - Licensed under the GNU GPL version 3 or higher.
+ -}
+
+module Command.LookupKey where
+
+import Common.Annex
+import Command
+import Annex.CatFile
+import Types.Key
+
+def :: [Command]
+def = [notBareRepo $
+	command "lookupkey" (paramRepeating paramFile) seek
+		SectionPlumbing "looks up key used for file"]
+
+seek :: [CommandSeek]
+seek = [withStrings start]
+
+start :: String -> CommandStart
+start file = do
+	liftIO . maybe exitFailure (putStrLn . key2file) =<< catKeyFile file
+	stop
diff --git a/GitAnnex.hs b/GitAnnex.hs
index 5b69a2d9dd..8ea0c9569e 100644
--- a/GitAnnex.hs
+++ b/GitAnnex.hs
@@ -20,6 +20,7 @@ import qualified Command.Drop
 import qualified Command.Move
 import qualified Command.Copy
 import qualified Command.Get
+import qualified Command.LookupKey
 import qualified Command.FromKey
 import qualified Command.DropKey
 import qualified Command.TransferKey
@@ -124,6 +125,7 @@ cmds = concat
 	, Command.Schedule.def
 	, Command.Ungroup.def
 	, Command.Vicfg.def
+	, Command.LookupKey.def
 	, Command.FromKey.def
 	, Command.DropKey.def
 	, Command.TransferKey.def
diff --git a/debian/changelog b/debian/changelog
index 128a161f6d..f39df1f8d4 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,6 +1,7 @@
 git-annex (5.20131214) UNRELEASED; urgency=low
 
   * Fix test suite to cover lock --force change.
+  * Add plumbing-level lookupkey command.
 
  -- Joey Hess <joeyh@debian.org>  Sun, 15 Dec 2013 13:32:49 -0400
 
diff --git a/doc/git-annex.mdwn b/doc/git-annex.mdwn
index 4602849c2d..5d61b8b40f 100644
--- a/doc/git-annex.mdwn
+++ b/doc/git-annex.mdwn
@@ -727,6 +727,13 @@ subdirectories).
   point to annexed content. Also handles injecting changes to unlocked
   files into the annex.
 
+* `lookupkey [file ...]`
+
+  This plumbing-level command looks up the key used for a file in the
+  index. The key is output to stdout. If there is no key (because
+  the file is not added to git, or is not a git-annex managed file),
+  nothing is output, and it exits nonzero.
+
 * `fromkey key file`
 
   This plumbing-level command can be used to manually set up a file