285 lines
9.1 KiB
Haskell
285 lines
9.1 KiB
Haskell
{- git trees
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-
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- Copyright 2016 Joey Hess <id@joeyh.name>
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-
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- Licensed under the GNU GPL version 3 or higher.
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-}
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{-# LANGUAGE BangPatterns, TypeSynonymInstances, FlexibleInstances #-}
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module Git.Tree (
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Tree(..),
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TreeContent(..),
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getTree,
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recordTree,
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TreeItem(..),
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adjustTree,
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) where
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import Common
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import Git
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import Git.FilePath
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import Git.Types
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import Git.Command
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import Git.Sha
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import qualified Git.LsTree as LsTree
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import qualified Utility.CoProcess as CoProcess
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import Numeric
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import System.Posix.Types
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import Control.Monad.IO.Class
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import qualified Data.Set as S
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import qualified Data.Map as M
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newtype Tree = Tree [TreeContent]
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deriving (Show)
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data TreeContent
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-- A blob object in the tree.
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= TreeBlob TopFilePath FileMode Sha
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-- A subtree that is already recorded in git, with a known sha.
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| RecordedSubTree TopFilePath Sha [TreeContent]
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-- A subtree that has not yet been recorded in git.
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| NewSubTree TopFilePath [TreeContent]
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-- A commit object that is part of a tree (used for submodules)
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| TreeCommit TopFilePath FileMode Sha
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deriving (Show, Eq, Ord)
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{- Gets the Tree for a Ref. -}
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getTree :: Ref -> Repo -> IO Tree
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getTree r repo = do
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(l, cleanup) <- lsTreeWithObjects r repo
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let !t = either (\e -> error ("ls-tree parse error:" ++ e)) id
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(extractTree l)
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void cleanup
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return t
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lsTreeWithObjects :: Ref -> Repo -> IO ([LsTree.TreeItem], IO Bool)
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lsTreeWithObjects = LsTree.lsTree' [Param "-t"]
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newtype MkTreeHandle = MkTreeHandle CoProcess.CoProcessHandle
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withMkTreeHandle :: (MonadIO m, MonadMask m) => Repo -> (MkTreeHandle -> m a) -> m a
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withMkTreeHandle repo a = bracketIO setup cleanup (a . MkTreeHandle)
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where
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setup = gitCoProcessStart False ps repo
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ps = [Param "mktree", Param "--batch", Param "-z"]
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cleanup = CoProcess.stop
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{- Records a Tree in the Repo, returning its Sha.
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-
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- Efficiently handles subtrees, by only recording ones that have not
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- already been recorded before. And even when many subtrees need to be
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- recorded, it's done with a single call to git mktree, using its batch
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- interface.
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-}
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recordTree :: Tree -> Repo -> IO Sha
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recordTree t repo = withMkTreeHandle repo $ \h -> recordTree' h t
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recordTree' :: MkTreeHandle -> Tree -> IO Sha
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recordTree' h (Tree l) = mkTree h =<< mapM (recordSubTree h) l
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{- Note that the returned RecordedSubTree does not have its [TreeContent]
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- list populated. This is a memory optimisation, since the list is not
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- used. -}
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recordSubTree :: MkTreeHandle -> TreeContent -> IO TreeContent
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recordSubTree h (NewSubTree d l) = do
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sha <- mkTree h =<< mapM (recordSubTree h) l
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return (RecordedSubTree d sha [])
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recordSubTree _ alreadyrecorded = return alreadyrecorded
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mkTree :: MkTreeHandle -> [TreeContent] -> IO Sha
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mkTree (MkTreeHandle cp) l = CoProcess.query cp send receive
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where
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send h = do
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forM_ l $ \i -> hPutStr h $ case i of
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TreeBlob f fm s -> mkTreeOutput fm BlobObject s f
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RecordedSubTree f s _ -> mkTreeOutput 0o040000 TreeObject s f
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NewSubTree _ _ -> error "recordSubTree internal error; unexpected NewSubTree"
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TreeCommit f fm s -> mkTreeOutput fm CommitObject s f
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hPutStr h "\NUL" -- signal end of tree to --batch
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receive h = getSha "mktree" (hGetLine h)
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mkTreeOutput :: FileMode -> ObjectType -> Sha -> TopFilePath -> String
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mkTreeOutput fm ot s f = concat
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[ showOct fm ""
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, " "
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, show ot
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, " "
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, fromRef s
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, "\t"
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, takeFileName (getTopFilePath f)
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, "\NUL"
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]
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data TreeItem = TreeItem TopFilePath FileMode Sha
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deriving (Show, Eq)
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treeItemToTreeContent :: TreeItem -> TreeContent
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treeItemToTreeContent (TreeItem f m s) = TreeBlob f m s
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treeItemsToTree :: [TreeItem] -> Tree
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treeItemsToTree = go M.empty
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where
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go m [] = Tree $ filter inTopTree (M.elems m)
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go m (i:is)
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| inTopTree p =
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go (M.insert p (treeItemToTreeContent i) m) is
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| otherwise = case M.lookup idir m of
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Just (NewSubTree d l) ->
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go (addsubtree idir m (NewSubTree d (c:l))) is
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_ ->
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go (addsubtree idir m (NewSubTree (asTopFilePath idir) [c])) is
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where
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p = gitPath i
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idir = takeDirectory p
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c = treeItemToTreeContent i
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addsubtree d m t
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| not (inTopTree d) =
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let m' = M.insert d t m
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in case M.lookup parent m' of
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Just (NewSubTree d' l) ->
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let l' = filter (\ti -> gitPath ti /= d) l
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in addsubtree parent m' (NewSubTree d' (t:l'))
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_ -> addsubtree parent m' (NewSubTree (asTopFilePath parent) [t])
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| otherwise = M.insert d t m
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where
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parent = takeDirectory d
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{- Flattens the top N levels of a Tree. -}
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flattenTree :: Int -> Tree -> Tree
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flattenTree 0 t = t
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flattenTree n (Tree l) = Tree (concatMap (go n) l)
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where
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go 0 c = [c]
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go _ b@(TreeBlob _ _ _) = [b]
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go n' (RecordedSubTree _ _ l') = concatMap (go (n'-1)) l'
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go n' (NewSubTree _ l') = concatMap (go (n'-1)) l'
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go _ c@(TreeCommit _ _ _) = [c]
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{- Applies an adjustment to items in a tree.
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-
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- While less flexible than using getTree and recordTree,
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- this avoids buffering the whole tree in memory.
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-}
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adjustTree
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:: (Functor m, MonadIO m, MonadMask m)
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=> (TreeItem -> m (Maybe TreeItem))
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-- ^ Adjust an item in the tree. Nothing deletes the item.
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-- Cannot move the item to a different tree.
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-> [TreeItem]
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-- ^ New items to add to the tree.
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-> [TopFilePath]
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-- ^ Files to remove from the tree.
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-> Ref
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-> Repo
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-> m Sha
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adjustTree adjusttreeitem addtreeitems removefiles r repo =
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withMkTreeHandle repo $ \h -> do
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(l, cleanup) <- liftIO $ lsTreeWithObjects r repo
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(l', _, _) <- go h False [] 1 inTopTree l
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l'' <- adjustlist h 0 inTopTree (const True) l'
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sha <- liftIO $ mkTree h l''
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void $ liftIO cleanup
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return sha
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where
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go _ wasmodified c _ _ [] = return (c, wasmodified, [])
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go h wasmodified c depth intree (i:is)
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| intree i = case readObjectType (LsTree.typeobj i) of
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Just BlobObject -> do
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let ti = TreeItem (LsTree.file i) (LsTree.mode i) (LsTree.sha i)
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v <- adjusttreeitem ti
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case v of
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Nothing -> go h True c depth intree is
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Just ti'@(TreeItem f m s) ->
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let !modified = wasmodified || ti' /= ti
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blob = TreeBlob f m s
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in go h modified (blob:c) depth intree is
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Just TreeObject -> do
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(sl, modified, is') <- go h False [] (depth+1) (beneathSubTree i) is
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sl' <- adjustlist h depth (inTree i) (beneathSubTree i) sl
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let slmodified = sl' /= sl
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subtree <- if modified || slmodified
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then liftIO $ recordSubTree h $ NewSubTree (LsTree.file i) sl'
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else return $ RecordedSubTree (LsTree.file i) (LsTree.sha i) []
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let !modified' = modified || slmodified || wasmodified
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go h modified' (subtree : c) depth intree is'
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Just CommitObject -> do
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let ti = TreeCommit (LsTree.file i) (LsTree.mode i) (LsTree.sha i)
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go h wasmodified (ti:c) depth intree is
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_ -> error ("unexpected object type \"" ++ LsTree.typeobj i ++ "\"")
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| otherwise = return (c, wasmodified, i:is)
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adjustlist h depth ishere underhere l = do
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let (addhere, rest) = partition ishere addtreeitems
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let l' = filter (not . removed) $
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map treeItemToTreeContent addhere ++ l
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let inl i = any (\t -> beneathSubTree t i) l'
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let (Tree addunderhere) = flattenTree depth $ treeItemsToTree $
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filter (\i -> underhere i && not (inl i)) rest
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addunderhere' <- liftIO $ mapM (recordSubTree h) addunderhere
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return (addunderhere'++l')
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removeset = S.fromList $ map (normalise . gitPath) removefiles
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removed (TreeBlob f _ _) = S.member (normalise (gitPath f)) removeset
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removed _ = False
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{- Assumes the list is ordered, with tree objects coming right before their
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- contents. -}
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extractTree :: [LsTree.TreeItem] -> Either String Tree
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extractTree l = case go [] inTopTree l of
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Right (t, []) -> Right (Tree t)
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Right _ -> parseerr "unexpected tree form"
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Left e -> parseerr e
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where
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go t _ [] = Right (t, [])
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go t intree (i:is)
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| intree i = case readObjectType (LsTree.typeobj i) of
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Just BlobObject ->
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let b = TreeBlob (LsTree.file i) (LsTree.mode i) (LsTree.sha i)
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in go (b:t) intree is
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Just TreeObject -> case go [] (beneathSubTree i) is of
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Right (subtree, is') ->
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let st = RecordedSubTree (LsTree.file i) (LsTree.sha i) subtree
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in go (st:t) intree is'
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Left e -> Left e
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Just CommitObject ->
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let c = TreeCommit (LsTree.file i) (LsTree.mode i) (LsTree.sha i)
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in go (c:t) intree is
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_ -> parseerr ("unexpected object type \"" ++ LsTree.typeobj i ++ "\"")
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| otherwise = Right (t, i:is)
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parseerr = Left
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class GitPath t where
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gitPath :: t -> FilePath
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instance GitPath FilePath where
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gitPath = id
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instance GitPath TopFilePath where
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gitPath = getTopFilePath
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instance GitPath TreeItem where
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gitPath (TreeItem f _ _) = gitPath f
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instance GitPath LsTree.TreeItem where
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gitPath = gitPath . LsTree.file
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instance GitPath TreeContent where
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gitPath (TreeBlob f _ _) = gitPath f
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gitPath (RecordedSubTree f _ _) = gitPath f
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gitPath (NewSubTree f _) = gitPath f
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gitPath (TreeCommit f _ _) = gitPath f
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inTopTree :: GitPath t => t -> Bool
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inTopTree = inTree "."
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inTree :: (GitPath t, GitPath f) => t -> f -> Bool
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inTree t f = gitPath t == takeDirectory (gitPath f)
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beneathSubTree :: (GitPath t, GitPath f) => t -> f -> Bool
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beneathSubTree t f = prefix `isPrefixOf` normalise (gitPath f)
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where
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tp = gitPath t
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prefix = if null tp then tp else addTrailingPathSeparator (normalise tp)
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