make view globs case-insensative, memoized, and bring back TFDA

I was careful to write the code so its clear how laziness memoizes it,
although it's likely that much less explicit currying would have had
the same effect. Verified that the memoization works using a Debug.Trace.

Annex/View.hs

@@ -5,6 +5,8 @@
  - Licensed under the GNU GPL version 3 or higher.
  -}
 
+{-# LANGUAGE CPP #-}
+
 module Annex.View where
 
 import Common.Annex
@@ -29,12 +31,17 @@ import qualified Data.Set as S
 import System.Path.WildMatch
 import "mtl" Control.Monad.Writer
 
+#ifdef WITH_TDFA
+import Text.Regex.TDFA
+import Text.Regex.TDFA.String
+#else
+import Text.Regex
+#endif
+
+
 data ViewChange = Unchanged | Narrowing | Widening
 	deriving (Ord, Eq, Show)
 
-matchGlob :: String -> String -> Bool
-matchGlob glob val = wildCheckCase glob val
-
 {- Each multivalued ViewFilter in a view results in another level of
  - subdirectory nesting. When a file matches multiple ways, it will appear
  - in multiple subdirectories. This means there is a bit of an exponential
@@ -73,7 +80,7 @@ refineView view field wanted
 			return $ v { viewFilter = newvf }
 		| otherwise = return v
 
-{- Combine old and new ViewFilters, yielding a results that matches
+{- Combine old and new ViewFilters, yielding a result that matches
  - either old+new, or only new.
  -
  - If we have FilterValues and change to a FilterGlob,
@@ -96,26 +103,13 @@ combineViewFilter old@(FilterValues olds) (FilterValues news)
 combineViewFilter (FilterValues _) newglob@(FilterGlob _) =
 	(newglob, Widening)
 combineViewFilter (FilterGlob oldglob) new@(FilterValues s)
-	| all (matchGlob oldglob . fromMetaValue) (S.toList s) = (new, Narrowing)
+	| all (matchGlob (compileGlob oldglob) . fromMetaValue) (S.toList s) = (new, Narrowing)
 	| otherwise = (new, Widening)
 combineViewFilter (FilterGlob old) newglob@(FilterGlob new)
 	| old == new = (newglob, Unchanged)
-	| matchGlob old new = (newglob, Narrowing)
+	| matchGlob (compileGlob old) new = (newglob, Narrowing)
 	| otherwise = (newglob, Widening)
 
-{- Checks if metadata matches a filter, and if so returns the value,
- - or values that match. -}
-matchFilter :: MetaData -> ViewComponent -> Maybe [MetaValue]
-matchFilter metadata (ViewComponent metafield (FilterValues s)) = nonEmptyList $
-	S.intersection s (currentMetaDataValues metafield metadata)
-matchFilter metadata (ViewComponent metafield (FilterGlob glob)) = nonEmptyList $
-	S.filter (matchGlob glob . fromMetaValue) (currentMetaDataValues metafield metadata)
-
-nonEmptyList :: S.Set a -> Maybe [a]
-nonEmptyList s
-	| S.null s = Nothing
-	| otherwise = Just $ S.toList s
-
 {- Converts a filepath used in a reference branch to the
  - filename that will be used in the view.
  -
@@ -153,24 +147,71 @@ fileViewReuse = takeFileName
  -
  - Of course if its MetaData does not match the View, it won't appear at
  - all.
+ -
+ - Note that for efficiency, it's useful to partially
+ - evaluate this function with the view parameter and reuse
+ - the result. The globs in the view will then be compiled and memoized.
  -}
 fileViews :: View -> MkFileView -> FilePath -> MetaData -> [FileView]
-fileViews view mkfileview file metadata
+fileViews view = 
-	| any isNothing matches = []
+	let matchers = map viewComponentMatcher (viewComponents view)
-	| otherwise =
+	in \mkfileview file metadata ->
+		let matches = map (\m -> m metadata) matchers
+		in if any isNothing matches
+			then []
+			else 
 				let paths = pathProduct $
 					map (map toViewPath) (visible matches)
 				in if null paths
 					then [mkfileview file]
 					else map (</> mkfileview file) paths
   where
-  	matches :: [Maybe [MetaValue]]
-	matches = map (matchFilter metadata) (viewComponents view)
-	visible :: [Maybe [MetaValue]] -> [[MetaValue]]
 	visible = map (fromJust . snd) .
 		filter (multiValue . fst) .
 		zip (map viewFilter (viewComponents view))
 
+{- Checks if metadata matches a ViewComponent filter, and if so
+ - returns the value, or values that match. Self-memoizing on ViewComponent. -}
+viewComponentMatcher :: ViewComponent -> (MetaData -> Maybe [MetaValue])
+viewComponentMatcher viewcomponent = \metadata -> 
+	let s = matcher (currentMetaDataValues metafield metadata)
+	in if S.null s then Nothing else Just (S.toList s)
+  where
+  	metafield = viewField viewcomponent
+	matcher = case viewFilter viewcomponent of
+		FilterValues s -> \values -> S.intersection s values
+		FilterGlob glob ->
+			let regex = compileGlob glob
+			in \values -> 
+				S.filter (matchGlob regex . fromMetaValue) values
+
+compileGlob :: String -> Regex
+compileGlob glob = 
+#ifdef WITH_TDFA
+	case compile (defaultCompOpt {caseSensitive = False}) defaultExecOpt regex of
+		Right r -> r
+		Left _ -> error $ "failed to compile regex: " ++ regex
+#else
+	mkRegexWithOpts regex False True
+#endif
+  where
+	regex = '^':wildToRegex glob
+
+matchGlob :: Regex -> String -> Bool
+matchGlob regex val = 
+#ifdef WITH_TDFA
+	case execute regex val of
+		Right (Just _) -> True
+		_ -> False
+#else
+	isJust $ matchRegex regex val
+#endif
+
+nonEmptyList :: S.Set a -> Maybe [a]
+nonEmptyList s
+	| S.null s = Nothing
+	| otherwise = Just $ S.toList s
+
 toViewPath :: MetaValue -> FilePath
 toViewPath = concatMap escapeslash . fromMetaValue
   where
@@ -268,9 +309,10 @@ applyView' mkfileview view = do
 			void $ stopUpdateIndex uh
 			void clean
   where
+	genfileviews = fileViews view mkfileview -- enables memoization
 	go uh hasher f (Just (k, _)) = do
 		metadata <- getCurrentMetaData k
-		forM_ (fileViews view mkfileview f metadata) $ \fv -> do
+		forM_ (genfileviews f metadata) $ \fv -> do
 			stagesymlink uh hasher fv =<< inRepo (gitAnnexLink fv k)
 	go uh hasher f Nothing
 		| "." `isPrefixOf` f = do