A way to match files in repositories in a group

--copies=group:number can now be used to match files that are present in a
specified number of repositories in a group.

Limit.hs

@@ -10,6 +10,7 @@ module Limit where
 import Text.Regex.PCRE.Light.Char8
 import System.Path.WildMatch
 import Data.Time.Clock.POSIX
+import qualified Data.Set as S
 
 import Common.Annex
 import qualified Annex
@@ -18,6 +19,7 @@ import qualified Remote
 import qualified Backend
 import Annex.Content
 import Logs.Trust
+import Logs.Group
 import Utility.HumanTime
 
 type Limit = Utility.Matcher.Token (FilePath -> Annex Bool)
@@ -86,21 +88,22 @@ addIn name = addLimit $ check $ if name == "." then inAnnex else inremote
 {- Adds a limit to skip files not believed to have the specified number
  - of copies. -}
 addCopies :: String -> Annex ()
-addCopies trust_num = addLimit . check $ readnum num
+addCopies want = addLimit . check $ readnum num
 	where
-		(num, mayCheckTrust) = case split ":" trust_num of
-			[trust, num'] -> (num', checkTrust (readtrust trust))
-			[num'] -> (num', const (return True))
-			_ -> bad
-		readnum = maybe bad id . readish
-		readtrust = maybe bad id . readTrust
+		(num, good) = case split ":" want of
+			[v, n] -> case readTrust v of
+				Just trust -> (n, checktrust trust)
+				Nothing -> (n, checkgroup v)
+			[n] -> (n, const $ return True)
+			_ -> error "bad value for --copies"
+		readnum = maybe (error "bad number for --copies") id . readish
 		check n = Backend.lookupFile >=> handle n
 		handle _ Nothing = return False
 		handle n (Just (key, _)) = do
-			us <- filterM mayCheckTrust =<< Remote.keyLocations key
+			us <- filterM good =<< Remote.keyLocations key
 			return $ length us >= n
-		checkTrust t u = (== t) <$> lookupTrust u
-		bad = error "bad number or trust:number for --copies"
+		checktrust t u = (== t) <$> lookupTrust u
+		checkgroup g u = S.member g <$> lookupGroups u
 
 {- Adds a limit to skip files not using a specified key-value backend. -}
 addInBackend :: String -> Annex ()

debian/changelog

@@ -1,6 +1,8 @@
 git-annex (3.20121002) UNRELEASED; urgency=low
 
   * group, ungroup: New commands to indicate groups of repositories.
+  * --copies=group:number can now be used to match files that are present
+    in a specified number of repositories in a group.
 
  -- Joey Hess <joeyh@debian.org>  Mon, 01 Oct 2012 15:09:49 -0400
 

doc/git-annex.mdwn

@@ -625,6 +625,12 @@ file contents are present at either of two repositories.
   copies, on remotes with the specified trust level. For example,
   "--copies=trusted:2"
 
+* --copies=groupname:number
+
+  Matches only files that git-annex believes have the specified number of
+  copies, on remotes in the specified group. For example,
+  "--copies=archival:2"
+
 * --inbackend=name
 
   Matches only files whose content is stored using the specified key-value