add git annex view command

(And a vpop command, which is still a bit buggy.)

Still need to do vadd and vrm, though this also adds their documentation.

Currently not very happy with the view log data serialization. I had to
lose the TDFA regexps temporarily, so I can have Read/Show instances of
View. I expect the view log format will change in some incompatable way
later, probably adding last known refs for the parent branch to View
or something like that.

Anyway, it basically works, although it's a bit slow looking up the
metadata. The actual git branch construction is about as fast as it can be
using the current git plumbing.

This commit was sponsored by Peter Hogg.

1 files changed, 74 insertions, 94 deletions

diff --git a/Annex/View.hs b/Annex/View.hs
index 890f2682a..0af46680b 100644
--- a/Annex/View.hs
+++ b/Annex/View.hs
@@ -5,61 +5,46 @@
  - Licensed under the GNU GPL version 3 or higher.
  -}
 
-{-# LANGUAGE CPP #-}
-
 module Annex.View where
 
 import Common.Annex
 import Types.View
 import Types.MetaData
-import qualified Git.Types as Git
-import qualified Git.Ref
+import qualified Git
 import qualified Git.DiffTree
 import qualified Git.Branch
-import Git.Sha (nullSha)
+import qualified Git.LsFiles
+import Git.UpdateIndex
+import Git.Sha
+import Git.HashObject
+import qualified Backend
+import Annex.Index
+import Annex.Link
+import Logs.MetaData
+import Logs.View
 
 import qualified Data.Set as S
-import Data.Char
 import System.Path.WildMatch
 import "mtl" Control.Monad.Writer
 
-#ifdef WITH_TDFA
-import Text.Regex.TDFA
-import Text.Regex.TDFA.String
-#else
-#endif
-
-matchGlob :: Glob -> String -> Bool
-#ifdef WITH_TDFA
-matchGlob (Glob _ r) s = case execute r s of
-	Right (Just _) -> True
-	_ -> False
-#else
-matchGlob (Glob g) = wildCheckCase g
-#endif
-
 data ViewChange = Unchanged | Narrowing | Widening
 	deriving (Ord, Eq, Show)
 
+matchGlob :: String -> String -> Bool
+matchGlob glob val = wildCheckCase glob val
+
 {- Updates a view, adding a new field to filter on (Narrowing), 
- - or allowing a new value in an existing field (Widening).
- -}
+ - or allowing a new value in an existing field (Widening). -}
 refineView :: View -> MetaField -> String -> (View, ViewChange)
 refineView view field wanted
-	| field `elem` (map viewField view) = 
-		let (view', viewchanges) = runWriter $ mapM updatefield view
-		in (view', maximum viewchanges)
-	| otherwise = (ViewComponent field viewfilter : view, Narrowing)
+	| field `elem` (map viewField components) = 
+		let (components', viewchanges) = runWriter $ mapM updatefield components
+		in (view { viewComponents = components' }, maximum viewchanges)
+	| otherwise = (view { viewComponents = ViewComponent field viewfilter : components }, Narrowing)
   where
+  	components = viewComponents view
 	viewfilter
-		| any (`elem` wanted) "*?" = 
-#ifdef WITH_TDFA
-			case compile defaultCompOpt defaultExecOpt ('^':wildToRegex wanted) of
-				Right r -> FilterGlob (Glob wanted r)
-				Left _ -> FilterValues $ S.singleton $ toMetaValue wanted
-#else
-			FilterGlob (Glob wanted)
-#endif
+		| any (`elem` wanted) "*?" = FilterGlob wanted
 		| otherwise = FilterValues $ S.singleton $ toMetaValue wanted
 	updatefield :: ViewComponent -> Writer [ViewChange] ViewComponent
 	updatefield v
@@ -96,14 +81,9 @@ combineViewFilter (FilterGlob oldglob) new@(FilterValues s)
 	| otherwise = (new, Widening)
 combineViewFilter (FilterGlob old) newglob@(FilterGlob new)
 	| old == new = (newglob, Unchanged)
-	| matchGlob old (getGlob new) = (newglob, Narrowing)
+	| matchGlob old new = (newglob, Narrowing)
 	| otherwise = (newglob, Widening)
 
-{- Can a ViewFilter match multiple different MetaValues? -}
-multiValue :: ViewFilter -> Bool
-multiValue (FilterValues s) = S.size s > 1
-multiValue (FilterGlob _) = True
-
 {- 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
@@ -113,7 +93,7 @@ multiValue (FilterGlob _) = True
  - through 5+ levels of subdirectories to find anything?
  -}
 viewTooLarge :: View -> Bool
-viewTooLarge view = length (filter (multiValue . viewFilter) view) > 5
+viewTooLarge view = length (filter (multiValue . viewFilter) (viewComponents view)) > 5
 
 {- Checks if metadata matches a filter, and if so returns the value,
  - or values that match. -}
@@ -166,15 +146,19 @@ fileViewFromReference f = concat
 fileViews :: View -> MkFileView -> FilePath -> MetaData -> [FileView]
 fileViews view mkfileview file metadata
 	| any isNothing matches = []
-	| otherwise = map (</> mkfileview file) $ pathProduct $ 
-		map (map toViewPath) (visible matches)
+	| otherwise =
+		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) view
+	matches = map (matchFilter metadata) (viewComponents view)
 	visible :: [Maybe [MetaValue]] -> [[MetaValue]]
 	visible = map (fromJust . snd) .
 		filter (multiValue . fst) .
-		zip (map viewFilter view)
+		zip (map viewFilter (viewComponents view))
 
 toViewPath :: MetaValue -> FilePath
 toViewPath = concatMap escapeslash . fromMetaValue
@@ -218,7 +202,7 @@ pathProduct (l:ls) = foldl combinel l ls
 fromView :: View -> FileView -> MetaData
 fromView view f = foldr (uncurry updateMetaData) newMetaData (zip fields values)
   where
-	visible = filter (multiValue . viewFilter) view
+	visible = filter (multiValue . viewFilter) (viewComponents view)
 	fields = map viewField visible
 	paths = splitDirectories $ dropFileName f
 	values = map fromViewPath paths
@@ -231,47 +215,19 @@ prop_view_roundtrips :: FilePath -> MetaData -> Bool
 prop_view_roundtrips f metadata = null f || viewTooLarge view ||
 	all hasfields (fileViews view fileViewFromReference f metadata)
   where
-	view = map (\(mf, mv) -> ViewComponent mf (FilterValues $ S.filter (not . null . fromMetaValue) mv))
-		(fromMetaData metadata)
-	visiblefields = sort (map viewField $ filter (multiValue . viewFilter) view)
+	view = View (Git.Ref "master") $
+		map (\(mf, mv) -> ViewComponent mf (FilterValues $ S.filter (not . null . fromMetaValue) mv))
+			(fromMetaData metadata)
+	visiblefields = sort (map viewField $ filter (multiValue . viewFilter) (viewComponents view))
 	hasfields fv = sort (map fst (fromMetaData (fromView view fv))) == visiblefields
 
-{- Generates a git branch name for a View.
- - 
- - There is no guarantee that each view gets a unique branch name,
- - but the branch name is used to express the view as well as possible.
- -}
-branchView :: View -> Git.Branch
-branchView view
-	| null name = Git.Ref "refs/views"
-	| otherwise = Git.Ref $ "refs/views/" ++ name
-  where
-	name = intercalate "/" $ map branchcomp view
-	branchcomp c
-		| multiValue (viewFilter c) = branchcomp' c
-		| otherwise = "(" ++ branchcomp' c ++ ")"
-	branchcomp' (ViewComponent metafield viewfilter)
-		| metafield == tagMetaField = branchvals viewfilter
-		| otherwise = concat
-			[ forcelegal (fromMetaField metafield)
-			, "="
-			, branchvals viewfilter
-			]
-	branchvals (FilterValues set) = forcelegal $
-		intercalate "," $ map fromMetaValue $ S.toList set
-	branchvals (FilterGlob glob) = forcelegal $ getGlob glob
-	forcelegal s
-		| Git.Ref.legal True s = s
-		| otherwise = map (\c -> if isAlphaNum c then c else '_') s
-
-prop_branchView_legal :: View -> Bool
-prop_branchView_legal = Git.Ref.legal False . show . branchView
-
 {- Applies a view to the currently checked out branch, generating a new
  - branch for the view.
  -}
 applyView :: View -> Annex Git.Branch
-applyView = applyView' fileViewFromReference
+applyView view = do
+	liftIO . nukeFile =<< fromRepo gitAnnexViewIndex
+	applyView' fileViewFromReference view
 
 {- Generates a new branch for a View, which must be a more narrow
  - version of the View originally used to generate the currently
@@ -283,11 +239,32 @@ narrowView = applyView' id
 {- Go through each file in the currently checked out branch.
  - If the file is not annexed, skip it, unless it's a dotfile in the top.
  - Look up the metadata of annexed files, and generate any FileViews,
- - and stage them into the (temporary) index.
+ - and stage them.
+ -
+ - Currently only works in indirect mode.
  -}
 applyView' :: MkFileView -> View -> Annex Git.Branch
-applyView' mkfileview view = genViewBranch view $ do
-	error "TODO"
+applyView' mkfileview view = do
+	top <- fromRepo Git.repoPath
+	(l, clean) <- inRepo $ Git.LsFiles.inRepo [top]
+	genViewBranch view $ do
+		uh <- inRepo Git.UpdateIndex.startUpdateIndex
+		hasher <- inRepo hashObjectStart
+		forM_ l $ \f ->
+			go uh hasher f =<< Backend.lookupFile f
+		liftIO $ do
+			hashObjectStop hasher
+			void $ stopUpdateIndex uh
+			void clean
+  where
+	go uh hasher f Nothing = noop -- TODO dotfiles
+	go uh hasher f (Just (k, _)) = do
+		metadata <- getCurrentMetaData k
+		forM_ (fileViews view mkfileview f metadata) $ \fv -> do
+			linktarget <- inRepo $ gitAnnexLink fv k
+			sha <- hashSymlink' hasher linktarget
+			liftIO . Git.UpdateIndex.streamUpdateIndex' uh
+				=<< inRepo (Git.UpdateIndex.stageSymlink fv sha)
 
 {- Applies a view to the reference branch, generating a new branch
  - for the View.
@@ -307,18 +284,21 @@ updateView view ref oldref = genViewBranch view $ do
 		| Git.DiffTree.dstsha diff == nullSha = error "TODO delete file"
 		| otherwise = error "TODO add file"
 
-{- Generates a branch for a view. This is done by creating a temporary
- - index file, which starts off empty. An action is run to stage the files
- - that will be in the branch. Then a commit is made, to the view branch.
- - The view branch is not checked out, but entering it will display the
- - view. -}
+{- Generates a branch for a view. This is done using a different index
+ - file. An action is run to stage the files that will be in the branch.
+ - Then a commit is made, to the view branch. The view branch is not
+ - checked out, but entering it will display the view. -}
 genViewBranch :: View -> Annex () -> Annex Git.Branch
-genViewBranch view a = withTempIndex $ do
+genViewBranch view a = withIndex $ do
 	a
 	let branch = branchView view
 	void $ inRepo $ Git.Branch.commit True (show branch) branch []
 	return branch
 
-{- -}
-withTempIndex :: Annex a -> Annex a
-withTempIndex a = error "TODO"
+{- Runs an action using the view index file.
+ - Note that the file does not necessarily exist, or can contain
+ - info staged for an old view. -}
+withIndex :: Annex a -> Annex a
+withIndex a = do
+	f <- fromRepo gitAnnexViewIndex
+	withIndexFile f a