matchexpression: New plumbing command to check if a preferred content expression matches some data.

Types/FileMatcher.hs

@@ -1,6 +1,6 @@
 {- git-annex file matcher types
  -
- - Copyright 2013 Joey Hess <id@joeyh.name>
+ - Copyright 2013-2016 Joey Hess <id@joeyh.name>
  -
  - Licensed under the GNU GPL version 3 or higher.
  -}
@@ -10,13 +10,16 @@ module Types.FileMatcher where
 import Types.UUID (UUID)
 import Types.Key (Key)
 import Utility.Matcher (Matcher, Token)
+import Utility.FileSize
 
+import Control.Monad.IO.Class
 import qualified Data.Map as M
 import qualified Data.Set as S
 
 data MatchInfo
 	= MatchingFile FileInfo
 	| MatchingKey Key
+	| MatchingInfo (OptInfo FilePath) (OptInfo Key) (OptInfo FileSize)
 
 data FileInfo = FileInfo
 	{ currFile :: FilePath
@@ -25,6 +28,14 @@ data FileInfo = FileInfo
 	-- ^ filepath to match on; may be relative to top of repo or cwd
 	}
 
+type OptInfo a = Either (IO a) a
+
+-- If the OptInfo is not available, accessing it may result in eg an
+-- exception being thrown.
+getInfo :: MonadIO m => OptInfo a -> m a
+getInfo (Right i) = pure i
+getInfo (Left e) = liftIO e
+
 type FileMatcherMap a = M.Map UUID (Utility.Matcher.Matcher (S.Set UUID -> MatchInfo -> a Bool))
 
 type MkLimit a = String -> Either String (MatchFiles a)