{- metadata based branch views - - Copyright 2014-2023 Joey Hess - - Licensed under the GNU AGPL version 3 or higher. -} {-# LANGUAGE OverloadedStrings, PackageImports #-} module Annex.View where import Annex.Common import Annex.View.ViewedFile import Types.View import Types.AdjustedBranch import Types.MetaData import Annex.MetaData import qualified Annex import qualified Annex.Branch import qualified Git import qualified Git.DiffTree as DiffTree import qualified Git.Branch import qualified Git.LsFiles import qualified Git.LsTree import qualified Git.Ref import Git.CatFile import Git.UpdateIndex import Git.Sha import Git.Types import Git.FilePath import Annex.WorkTree import Annex.GitOverlay import Annex.Link import Annex.CatFile import Annex.Concurrent import Annex.Content.Presence import Logs import Logs.MetaData import Logs.View import Utility.Glob import Types.Command import CmdLine.Action import qualified Utility.RawFilePath as R import qualified Data.Text as T import qualified Data.ByteString as B import qualified Data.Set as S import qualified Data.Map as M import qualified System.FilePath.ByteString as P import Control.Concurrent.Async import "mtl" Control.Monad.Writer {- Each visible 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 - blowup with a single file appearing in a crazy number of places! - - Capping the view size to 5 is reasonable; why wants to dig - through 5+ levels of subdirectories to find anything? -} viewTooLarge :: View -> Bool viewTooLarge view = visibleViewSize view > 5 visibleViewSize :: View -> Int visibleViewSize = length . filter viewVisible . viewComponents {- Parses field=value, field!=value, field?=value, tag, !tag, and ?tag - - Note that the field may not be a legal metadata field name, - but it's let through anyway. - This is useful when matching on directory names with spaces, - which are not legal MetaFields. -} parseViewParam :: ViewUnset -> String -> (MetaField, ViewFilter) parseViewParam vu s = case separate (== '=') s of ('!':tag, []) | not (null tag) -> ( tagMetaField , mkExcludeValues tag ) ('?':tag, []) | not (null tag) -> ( tagMetaField , mkFilterOrUnsetValues tag ) (tag, []) -> ( tagMetaField , mkFilterValues tag ) (field, wanted) | end field == "!" -> ( mkMetaFieldUnchecked (T.pack (beginning field)) , mkExcludeValues wanted ) | end field == "?" -> ( mkMetaFieldUnchecked (T.pack (beginning field)) , mkFilterOrUnsetValues wanted ) | otherwise -> ( mkMetaFieldUnchecked (T.pack field) , mkFilterValues wanted ) where mkExcludeValues = ExcludeValues . S.singleton . toMetaValue . encodeBS mkFilterValues v | any (`elem` v) ['*', '?'] = FilterGlob v | otherwise = FilterValues $ S.singleton $ toMetaValue $ encodeBS v mkFilterOrUnsetValues v | any (`elem` v) ['*', '?'] = FilterGlobOrUnset v vu | otherwise = FilterValuesOrUnset (S.singleton $ toMetaValue $ encodeBS v) vu data ViewChange = Unchanged | Narrowing | Widening deriving (Ord, Eq, Show) {- Updates a view, adding new fields to filter on (Narrowing), - or allowing new values in an existing field (Widening). -} refineView :: View -> [(MetaField, ViewFilter)] -> (View, ViewChange) refineView origview = checksize . calc Unchanged origview where calc c v [] = (v, c) calc c v ((f, vf):rest) = let (v', c') = refine v f vf in calc (max c c') v' rest refine view field vf | field `elem` map viewField (viewComponents view) = let (components', viewchanges) = runWriter $ mapM (\c -> updateViewComponent c field vf) (viewComponents view) viewchange = if field `elem` map viewField (viewComponents origview) then maximum viewchanges else Narrowing in (view { viewComponents = components' }, viewchange) | otherwise = let component = mkViewComponent field vf view' = view { viewComponents = component : viewComponents view } in (view', Narrowing) checksize r@(v, _) | viewTooLarge v = giveup $ "View is too large (" ++ show (visibleViewSize v) ++ " levels of subdirectories)" | otherwise = r updateViewComponent :: ViewComponent -> MetaField -> ViewFilter -> Writer [ViewChange] ViewComponent updateViewComponent c field vf | viewField c == field = do let (newvf, viewchange) = combineViewFilter (viewFilter c) vf tell [viewchange] return $ mkViewComponent field newvf | otherwise = return c {- Adds an additional filter to a view. This can only result in narrowing - the view. Multivalued filters are added in non-visible form. -} filterView :: View -> [(MetaField, ViewFilter)] -> View filterView v vs = v { viewComponents = viewComponents f' ++ viewComponents v} where f = fst $ refineView (v {viewComponents = []}) vs f' = f { viewComponents = map toinvisible (viewComponents f) } toinvisible c = c { viewVisible = False } {- Combine old and new ViewFilters, yielding a result that matches - either old+new, or only new. Which depends on the types of things - being combined. -} combineViewFilter :: ViewFilter -> ViewFilter -> (ViewFilter, ViewChange) combineViewFilter old@(FilterValues olds) (FilterValues news) | combined == old = (combined, Unchanged) | otherwise = (combined, Widening) where combined = FilterValues (S.union olds news) combineViewFilter old@(ExcludeValues olds) (ExcludeValues news) | combined == old = (combined, Unchanged) | otherwise = (combined, Narrowing) where combined = ExcludeValues (S.union olds news) {- If we have FilterValues and change to a FilterGlob, - it's always a widening change, because the glob could match other - values. OTOH, going the other way, it's a Narrowing change if the old - glob matches all the new FilterValues. -} combineViewFilter (FilterValues _) newglob@(FilterGlob _) = (newglob, Widening) combineViewFilter (FilterGlob oldglob) new@(FilterValues s) | all (matchGlob (compileGlob oldglob CaseInsensitive (GlobFilePath False)) . decodeBS . fromMetaValue) (S.toList s) = (new, Narrowing) | otherwise = (new, Widening) {- With two globs, the old one is discarded, and the new one is used. - We can tell if that's a narrowing change by checking if the old - glob matches the new glob. For example, "*" matches "foo*", - so that's narrowing. While "f?o" does not match "f??", so that's - widening. -} combineViewFilter (FilterGlob old) newglob@(FilterGlob new) | old == new = (newglob, Unchanged) | matchGlob (compileGlob old CaseInsensitive (GlobFilePath False)) new = (newglob, Narrowing) | otherwise = (newglob, Widening) {- Combining FilterValuesOrUnset and FilterGlobOrUnset with FilterValues - and FilterGlob maintains the OrUnset if the second parameter has it, - and is otherwise the same as combining without OrUnset, except that - eliminating the OrUnset can be narrowing, and adding it can be widening. -} combineViewFilter old@(FilterValuesOrUnset olds _) (FilterValuesOrUnset news newvu) | combined == old = (combined, Unchanged) | otherwise = (combined, Widening) where combined = FilterValuesOrUnset (S.union olds news) newvu combineViewFilter (FilterValues olds) (FilterValuesOrUnset news vu) = (combined, Widening) where combined = FilterValuesOrUnset (S.union olds news) vu combineViewFilter old@(FilterValuesOrUnset olds _) (FilterValues news) | combined == old = (combined, Narrowing) | otherwise = (combined, Widening) where combined = FilterValues (S.union olds news) combineViewFilter (FilterValuesOrUnset _ _) newglob@(FilterGlob _) = (newglob, Widening) combineViewFilter (FilterGlob _) new@(FilterValuesOrUnset _ _) = (new, Widening) combineViewFilter (FilterValues _) newglob@(FilterGlobOrUnset _ _) = (newglob, Widening) combineViewFilter (FilterValuesOrUnset _ _) newglob@(FilterGlobOrUnset _ _) = (newglob, Widening) combineViewFilter (FilterGlobOrUnset oldglob _) new@(FilterValues _) = combineViewFilter (FilterGlob oldglob) new combineViewFilter (FilterGlobOrUnset oldglob _) new@(FilterValuesOrUnset _ _) = let (_, viewchange) = combineViewFilter (FilterGlob oldglob) new in (new, viewchange) combineViewFilter (FilterGlobOrUnset old _) newglob@(FilterGlobOrUnset new _) | old == new = (newglob, Unchanged) | matchGlob (compileGlob old CaseInsensitive (GlobFilePath False)) new = (newglob, Narrowing) | otherwise = (newglob, Widening) combineViewFilter (FilterGlob _) newglob@(FilterGlobOrUnset _ _) = (newglob, Widening) combineViewFilter (FilterGlobOrUnset _ _) newglob@(FilterGlob _) = (newglob, Narrowing) {- There is not a way to filter a value and also apply an exclude. So: - When adding an exclude to a filter, use only the exclude. - When adding a filter to an exclude, use only the filter. -} combineViewFilter (FilterGlob _) new@(ExcludeValues _) = (new, Narrowing) combineViewFilter (ExcludeValues _) new@(FilterGlob _) = (new, Widening) combineViewFilter (FilterValues _) new@(ExcludeValues _) = (new, Narrowing) combineViewFilter (ExcludeValues _) new@(FilterValues _) = (new, Widening) combineViewFilter (FilterValuesOrUnset _ _) new@(ExcludeValues _) = (new, Narrowing) combineViewFilter (ExcludeValues _) new@(FilterValuesOrUnset _ _) = (new, Widening) combineViewFilter (FilterGlobOrUnset _ _) new@(ExcludeValues _) = (new, Narrowing) combineViewFilter (ExcludeValues _) new@(FilterGlobOrUnset _ _) = (new, Widening) {- Generates views for a file from a branch, based on its metadata - and the filename used in the branch. - - Note that a file may appear multiple times in a view, when it - has multiple matching values for a MetaField used in the View. - - 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. -} viewedFiles :: View -> MkViewedFile -> FilePath -> MetaData -> [ViewedFile] viewedFiles view = let matchers = map viewComponentMatcher (viewComponents view) in \mkviewedfile 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 [mkviewedfile file] else map ( mkviewedfile file) paths where visible = map (fromJust . snd) . filter (viewVisible . fst) . zip (viewComponents view) toviewpath (MatchingMetaValue v) = toViewPath v toviewpath (MatchingUnset v) = toViewPath (toMetaValue (encodeBS v)) data MatchingValue = MatchingMetaValue MetaValue | MatchingUnset String {- 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 [MatchingValue]) viewComponentMatcher viewcomponent = \metadata -> matcher Nothing (viewFilter viewcomponent) (currentMetaDataValues metafield metadata) where metafield = viewField viewcomponent matcher matchunset (FilterValues s) = \values -> setmatches matchunset $ S.intersection s values matcher matchunset (FilterGlob glob) = let cglob = compileGlob glob CaseInsensitive (GlobFilePath False) in \values -> setmatches matchunset $ S.filter (matchGlob cglob . decodeBS . fromMetaValue) values matcher _ (ExcludeValues excludes) = \values -> if S.null (S.intersection values excludes) then Just [] else Nothing matcher _ (FilterValuesOrUnset s (ViewUnset u)) = matcher (Just [MatchingUnset u]) (FilterValues s) matcher _ (FilterGlobOrUnset glob (ViewUnset u)) = matcher (Just [MatchingUnset u]) (FilterGlob glob) setmatches matchunset s | S.null s = matchunset | otherwise = Just $ map MatchingMetaValue (S.toList s) -- This is '∕', a unicode character that displays the same as '/' but is -- not it. It is encoded using the filesystem encoding, which allows it -- to be used even when not in a unicode capable locale. pseudoSlash :: String pseudoSlash = "\56546\56456\56469" -- And this is '╲' similarly. pseudoBackslash :: String pseudoBackslash = "\56546\56469\56498" -- And this is '﹕' similarly. pseudoColon :: String pseudoColon = "\56559\56505\56469" toViewPath :: MetaValue -> FilePath toViewPath = escapepseudo [] . decodeBS . fromMetaValue where escapepseudo s ('/':cs) = escapepseudo (pseudoSlash:s) cs escapepseudo s ('\\':cs) = escapepseudo (pseudoBackslash:s) cs escapepseudo s (':':cs) = escapepseudo (pseudoColon:s) cs escapepseudo s ('%':cs) = escapepseudo ("%%":s) cs escapepseudo s (c1:c2:c3:cs) | [c1,c2,c3] == pseudoSlash = escapepseudo ("%":pseudoSlash:s) cs | [c1,c2,c3] == pseudoBackslash = escapepseudo ("%":pseudoBackslash:s) cs | [c1,c2,c3] == pseudoColon = escapepseudo ("%":pseudoColon:s) cs | otherwise = escapepseudo ([c1]:s) (c2:c3:cs) escapepseudo s (c:cs) = escapepseudo ([c]:s) cs escapepseudo s [] = concat (reverse s) fromViewPath :: FilePath -> MetaValue fromViewPath = toMetaValue . encodeBS . deescapepseudo [] where deescapepseudo s ('%':escapedc:cs) = deescapepseudo ([escapedc]:s) cs deescapepseudo s (c1:c2:c3:cs) | [c1,c2,c3] == pseudoSlash = deescapepseudo ("/":s) cs | [c1,c2,c3] == pseudoBackslash = deescapepseudo ("\\":s) cs | [c1,c2,c3] == pseudoColon = deescapepseudo (":":s) cs | otherwise = deescapepseudo ([c1]:s) (c2:c3:cs) deescapepseudo s cs = concat (reverse (cs:s)) prop_viewPath_roundtrips :: MetaValue -> Bool prop_viewPath_roundtrips v = fromViewPath (toViewPath v) == v pathProduct :: [[FilePath]] -> [FilePath] pathProduct [] = [] pathProduct (l:ls) = foldl combinel l ls where combinel xs ys = [combine x y | x <- xs, y <- ys] {- Extracts the metadata from a ViewedFile, based on the view that was used - to construct it. - - Derived metadata is excluded. -} fromView :: View -> ViewedFile -> MetaData fromView view f = MetaData $ m `M.difference` derived where m = M.fromList $ map convfield $ filter (not . isviewunset) (zip visible values) visible = filter viewVisible (viewComponents view) paths = splitDirectories (dropFileName f) values = map (S.singleton . fromViewPath) paths MetaData derived = getViewedFileMetaData f convfield (vc, v) = (viewField vc, v) -- When a directory is the one used to hold files that don't -- have the metadata set, don't include it in the MetaData. isviewunset (vc, v) = case viewFilter vc of FilterValues {} -> False FilterGlob {} -> False ExcludeValues {} -> False FilterValuesOrUnset _ (ViewUnset vu) -> isviewunset' vu v FilterGlobOrUnset _ (ViewUnset vu) -> isviewunset' vu v isviewunset' vu v = S.member (fromViewPath vu) v {- Constructing a view that will match arbitrary metadata, and applying - it to a file yields a set of ViewedFile which all contain the same - MetaFields that were present in the input metadata - (excluding fields that are not visible). -} prop_view_roundtrips :: AssociatedFile -> MetaData -> Bool -> Bool prop_view_roundtrips (AssociatedFile Nothing) _ _ = True prop_view_roundtrips (AssociatedFile (Just f)) metadata visible = or [ B.null (P.takeFileName f) && B.null (P.takeDirectory f) , viewTooLarge view , all hasfields (viewedFiles view (viewedFileFromReference' Nothing Nothing) (fromRawFilePath f) metadata) ] where view = View (Git.Ref "foo") $ map (\(mf, mv) -> ViewComponent mf (FilterValues $ S.filter (not . B.null . fromMetaValue) mv) visible) (fromMetaData metadata) visiblefields = sort (map viewField $ filter viewVisible (viewComponents view)) hasfields fv = sort (map fst (fromMetaData (fromView view fv))) == visiblefields {- A directory foo/bar/baz/ is turned into metadata fields - /=foo, foo/=bar, foo/bar/=baz. - - Note that this may generate MetaFields that legalField rejects. - This is necessary to have a 1:1 mapping between directory names and - fields. So this MetaData cannot safely be serialized. -} getDirMetaData :: FilePath -> MetaData getDirMetaData d = MetaData $ M.fromList $ zip fields values where dirs = splitDirectories d fields = map (mkMetaFieldUnchecked . T.pack . addTrailingPathSeparator . joinPath) (inits dirs) values = map (S.singleton . toMetaValue . encodeBS . fromMaybe "" . headMaybe) (tails dirs) getWorkTreeMetaData :: FilePath -> MetaData getWorkTreeMetaData = getDirMetaData . dropFileName getViewedFileMetaData :: FilePath -> MetaData getViewedFileMetaData = getDirMetaData . dirFromViewedFile . takeFileName {- Applies a view to the currently checked out branch, generating a new - branch for the view. -} applyView :: View -> Maybe Adjustment -> Annex Git.Branch applyView v ma = do gc <- Annex.getGitConfig applyView' (viewedFileFromReference gc) getWorkTreeMetaData v ma {- Generates a new branch for a View, which must be a more narrow - version of the View originally used to generate the currently - checked out branch. That is, it must match a subset of the files - in view, not any others. -} narrowView :: View -> Maybe Adjustment -> Annex Git.Branch narrowView = applyView' viewedFileReuse getViewedFileMetaData {- Go through each staged file. - If the file is not annexed, skip it, unless it's a dotfile in the top, - or a file in a dotdir in the top. - Look up the metadata of annexed files, and generate any ViewedFiles, - and stage them. -} applyView' :: MkViewedFile -> (FilePath -> MetaData) -> View -> Maybe Adjustment -> Annex Git.Branch applyView' mkviewedfile getfilemetadata view madj = do top <- fromRepo Git.repoPath (l, clean) <- inRepo $ Git.LsFiles.inRepoDetails [] [top] applyView'' mkviewedfile getfilemetadata view madj l clean $ \(f, sha, mode) -> do topf <- inRepo (toTopFilePath f) k <- lookupKey f return (topf, sha, toTreeItemType mode, k) genViewBranch view madj applyView'' :: MkViewedFile -> (FilePath -> MetaData) -> View -> Maybe Adjustment -> [t] -> IO Bool -> (t -> Annex (TopFilePath, Sha, Maybe TreeItemType, Maybe Key)) -> Annex () applyView'' mkviewedfile getfilemetadata view madj l clean conv = do viewg <- withNewViewIndex gitRepo withUpdateIndex viewg $ \uh -> do g <- Annex.gitRepo gc <- Annex.getGitConfig -- Streaming the metadata like this is an optimisation. catObjectStream g $ \mdfeeder mdcloser mdreader -> do tid <- liftIO . async =<< forkState (getmetadata gc mdfeeder mdcloser l) process uh mdreader join (liftIO (wait tid)) liftIO $ void clean where genviewedfiles = viewedFiles view mkviewedfile -- enables memoization getmetadata _ _ mdcloser [] = liftIO mdcloser getmetadata gc mdfeeder mdcloser (t:ts) = do v@(topf, _sha, _treeitemtype, mkey) <- conv t let feed mdlogf = liftIO $ mdfeeder (v, Git.Ref.branchFileRef Annex.Branch.fullname mdlogf) case mkey of Just key -> feed (metaDataLogFile gc key) Nothing -- Handle toplevel dotfiles that are not -- annexed files by feeding through a query -- for dummy metadata. Calling -- Git.UpdateIndex.streamUpdateIndex' -- here would race with process's calls -- to it. | "." `B.isPrefixOf` getTopFilePath topf -> feed "dummy" | otherwise -> noop getmetadata gc mdfeeder mdcloser ts process uh mdreader = liftIO mdreader >>= \case Just ((topf, _, mtreeitemtype, Just k), mdlog) -> do let metadata = maybe emptyMetaData parseCurrentMetaData mdlog let f = fromRawFilePath $ getTopFilePath topf let metadata' = getfilemetadata f `unionMetaData` metadata forM_ (genviewedfiles f metadata') $ \fv -> do f' <- fromRepo (fromTopFilePath $ asTopFilePath $ toRawFilePath fv) stagefile uh f' k mtreeitemtype process uh mdreader Just ((topf, sha, Just treeitemtype, Nothing), _) -> do liftIO $ Git.UpdateIndex.streamUpdateIndex' uh $ pureStreamer $ updateIndexLine sha treeitemtype topf process uh mdreader Just _ -> process uh mdreader Nothing -> return () stagefile uh f k mtreeitemtype = case madj of Nothing -> stagesymlink uh f k Just (LinkAdjustment UnlockAdjustment) -> stagepointerfile uh f k mtreeitemtype Just (LinkPresentAdjustment UnlockPresentAdjustment) -> ifM (inAnnex k) ( stagepointerfile uh f k mtreeitemtype , stagesymlink uh f k ) Just (PresenceAdjustment HideMissingAdjustment (Just UnlockAdjustment)) -> whenM (inAnnex k) $ stagepointerfile uh f k mtreeitemtype Just (PresenceAdjustment HideMissingAdjustment _) -> whenM (inAnnex k) $ stagesymlink uh f k _ -> stagesymlink uh f k stagesymlink uh f k = do linktarget <- calcRepo (gitAnnexLink f k) sha <- hashSymlink linktarget liftIO . Git.UpdateIndex.streamUpdateIndex' uh =<< inRepo (Git.UpdateIndex.stageSymlink f sha) stagepointerfile uh f k mtreeitemtype = do let treeitemtype = if mtreeitemtype == Just TreeExecutable then TreeExecutable else TreeFile sha <- hashPointerFile k liftIO . Git.UpdateIndex.streamUpdateIndex' uh =<< inRepo (Git.UpdateIndex.stageFile sha treeitemtype f) {- Updates the current view with any changes that have been made to its - parent branch or the metadata since the view was created or last updated. - - When there were changes, returns a ref to a commit for the updated view. - Does not update the view branch with it. - - This is not very optimised. An incremental update would be possible to - implement and would be faster, but more complicated. -} updateView :: View -> Maybe Adjustment -> Annex (Maybe Git.Ref) updateView view madj = do (l, clean) <- inRepo $ Git.LsTree.lsTree Git.LsTree.LsTreeRecursive (Git.LsTree.LsTreeLong True) (viewParentBranch view) gc <- Annex.getGitConfig applyView'' (viewedFileFromReference gc) getWorkTreeMetaData view madj l clean $ \ti -> do let ref = Git.Ref.branchFileRef (viewParentBranch view) (getTopFilePath (Git.LsTree.file ti)) k <- case Git.LsTree.size ti of Nothing -> catKey ref Just sz -> catKey' ref sz return ( (Git.LsTree.file ti) , (Git.LsTree.sha ti) , (toTreeItemType (Git.LsTree.mode ti)) , k ) oldcommit <- inRepo $ Git.Ref.sha (branchView view madj) oldtree <- maybe (pure Nothing) (inRepo . Git.Ref.tree) oldcommit newtree <- withViewIndex $ inRepo Git.Branch.writeTree if oldtree /= Just newtree then Just <$> do cmode <- annexCommitMode <$> Annex.getGitConfig let msg = "updated " ++ fromRef (branchView view madj) let parent = catMaybes [oldcommit] inRepo (Git.Branch.commitTree cmode [msg] parent newtree) else return Nothing {- Diff between currently checked out branch and staged changes, and - update metadata to reflect the changes that are being committed to the - view. - - Adding a file to a directory adds the metadata represented by - that directory to the file, and removing a file from a directory - removes the metadata. - - Note that removes must be handled before adds. This is so - that moving a file from x/foo/ to x/bar/ adds back the metadata for x. -} withViewChanges :: (ViewedFile -> Key -> CommandStart) -> (ViewedFile -> Key -> CommandStart) -> Annex () withViewChanges addmeta removemeta = do (diffs, cleanup) <- inRepo $ DiffTree.diffIndex Git.Ref.headRef forM_ diffs handleremovals forM_ diffs handleadds void $ liftIO cleanup where handleremovals item | DiffTree.srcsha item `notElem` nullShas = handlechange item removemeta =<< catKey (DiffTree.srcsha item) | otherwise = noop handleadds item | DiffTree.dstsha item `notElem` nullShas = handlechange item addmeta =<< catKey (DiffTree.dstsha item) | otherwise = noop handlechange item a = maybe noop (void . commandAction . a (fromRawFilePath $ getTopFilePath $ DiffTree.file item)) {- 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. -} withViewIndex :: Annex a -> Annex a withViewIndex = withIndexFile ViewIndexFile . const withNewViewIndex :: Annex a -> Annex a withNewViewIndex a = do liftIO . removeWhenExistsWith R.removeLink =<< fromRepo gitAnnexViewIndex withViewIndex a {- Generates a branch for a view, using the view index file - to make a commit to the view branch. The view branch is not - checked out, but entering it will display the view. -} genViewBranch :: View -> Maybe Adjustment -> Annex Git.Branch genViewBranch view madj = withViewIndex $ do let branch = branchView view madj cmode <- annexCommitMode <$> Annex.getGitConfig void $ inRepo $ Git.Branch.commit cmode True (fromRef branch) branch [] return branch withCurrentView :: (View -> Maybe Adjustment -> Annex a) -> Annex a withCurrentView a = maybe (giveup "Not in a view.") (uncurry a) =<< currentView