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|
{- git trees
-
- Copyright 2016 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU GPL version 3 or higher.
-}
{-# LANGUAGE BangPatterns #-}
module Git.Tree (
Tree(..),
TreeContent(..),
getTree,
recordTree,
TreeItem(..),
adjustTree,
) where
import Common
import Git
import Git.FilePath
import Git.Types
import Git.Command
import Git.Sha
import qualified Git.LsTree as LsTree
import qualified Utility.CoProcess as CoProcess
import Numeric
import System.Posix.Types
import Control.Monad.IO.Class
newtype Tree = Tree [TreeContent]
deriving (Show)
data TreeContent
= TreeBlob TopFilePath FileMode Sha
-- A subtree that is already recorded in git, with a known sha.
| RecordedSubTree TopFilePath Sha [TreeContent]
-- A subtree that has not yet been recorded in git.
| NewSubTree TopFilePath [TreeContent]
deriving (Show)
{- Gets the Tree for a Ref. -}
getTree :: Ref -> Repo -> IO Tree
getTree r repo = do
(l, cleanup) <- lsTreeWithObjects r repo
let !t = either (\e -> error ("ls-tree parse error:" ++ e)) id
(extractTree l)
void cleanup
return t
lsTreeWithObjects :: Ref -> Repo -> IO ([LsTree.TreeItem], IO Bool)
lsTreeWithObjects = LsTree.lsTree' [Param "-t"]
newtype MkTreeHandle = MkTreeHandle CoProcess.CoProcessHandle
withMkTreeHandle :: (MonadIO m, MonadMask m) => Repo -> (MkTreeHandle -> m a) -> m a
withMkTreeHandle repo a = bracketIO setup cleanup (a . MkTreeHandle)
where
setup = CoProcess.rawMode =<< gitCoProcessStart False ps repo
ps = [Param "mktree", Param "--batch", Param "-z"]
cleanup = CoProcess.stop
{- Records a Tree in the Repo, returning its Sha.
-
- Efficiently handles subtrees, by only recording ones that have not
- already been recorded before. And even when many subtrees need to be
- recorded, it's done with a single call to git mktree, using its batch
- interface.
-}
recordTree :: Tree -> Repo -> IO Sha
recordTree t repo = withMkTreeHandle repo $ \h -> recordTree' h t
recordTree' :: MkTreeHandle -> Tree -> IO Sha
recordTree' h (Tree l) = mkTree h =<< mapM (recordSubTree h) l
{- Note that the returned RecordedSubTree does not have its [TreeContent]
- list populated. This is a memory optimisation, since the list is not
- used. -}
recordSubTree :: MkTreeHandle -> TreeContent -> IO TreeContent
recordSubTree h (NewSubTree d l) = do
sha <- mkTree h =<< mapM (recordSubTree h) l
return (RecordedSubTree d sha [])
recordSubTree _ alreadyrecorded = return alreadyrecorded
mkTree :: MkTreeHandle -> [TreeContent] -> IO Sha
mkTree (MkTreeHandle cp) l = CoProcess.query cp send receive
where
send h = do
forM_ l $ \i -> hPutStr h $ case i of
TreeBlob f fm s -> mkTreeOutput fm BlobObject s f
RecordedSubTree f s _ -> mkTreeOutput 0o040000 TreeObject s f
NewSubTree _ _ -> error "recordSubTree internal error; unexpected NewSubTree"
hPutStr h "\NUL" -- signal end of tree to --batch
receive h = getSha "mktree" (hGetLine h)
mkTreeOutput :: FileMode -> ObjectType -> Sha -> TopFilePath -> String
mkTreeOutput fm ot s f = concat
[ showOct fm ""
, " "
, show ot
, " "
, fromRef s
, "\t"
, takeFileName (getTopFilePath f)
, "\NUL"
]
data TreeItem = TreeItem TopFilePath FileMode Sha
deriving (Eq)
{- Applies an adjustment to items in a tree.
-
- While less flexible than using getTree and recordTree, this avoids
- buffering the whole tree in memory.
-}
adjustTree :: (MonadIO m, MonadMask m) => (TreeItem -> m (Maybe TreeItem)) -> Ref -> Repo -> m Sha
adjustTree adjust r repo = withMkTreeHandle repo $ \h -> do
(l, cleanup) <- liftIO $ lsTreeWithObjects r repo
(l', _, _) <- go h False [] topTree l
sha <- liftIO $ mkTree h l'
void $ liftIO cleanup
return sha
where
go _ wasmodified c _ [] = return (c, wasmodified, [])
go h wasmodified c intree (i:is)
| intree i =
case readObjectType (LsTree.typeobj i) of
Just BlobObject -> do
let ti = TreeItem (LsTree.file i) (LsTree.mode i) (LsTree.sha i)
v <- adjust ti
case v of
Nothing -> go h True c intree is
Just ti'@(TreeItem f m s) ->
let !modified = wasmodified || ti' /= ti
blob = TreeBlob f m s
in go h modified (blob:c) intree is
Just TreeObject -> do
(sl, modified, is') <- go h False [] (subTree i) is
subtree <- if modified
then liftIO $ recordSubTree h $ NewSubTree (LsTree.file i) sl
else return $ RecordedSubTree (LsTree.file i) (LsTree.sha i) []
let !modified' = modified || wasmodified
go h modified' (subtree : c) intree is'
_ -> error ("unexpected object type \"" ++ LsTree.typeobj i ++ "\"")
| otherwise = return (c, wasmodified, i:is)
{- Assumes the list is ordered, with tree objects coming right before their
- contents. -}
extractTree :: [LsTree.TreeItem] -> Either String Tree
extractTree l = case go [] topTree l of
Right (t, []) -> Right (Tree t)
Right _ -> parseerr "unexpected tree form"
Left e -> parseerr e
where
go t _ [] = Right (t, [])
go t intree (i:is)
| intree i =
case readObjectType (LsTree.typeobj i) of
Just BlobObject ->
let b = TreeBlob (LsTree.file i) (LsTree.mode i) (LsTree.sha i)
in go (b:t) intree is
Just TreeObject -> case go [] (subTree i) is of
Right (subtree, is') ->
let st = RecordedSubTree (LsTree.file i) (LsTree.sha i) subtree
in go (st:t) intree is'
Left e -> Left e
_ -> parseerr ("unexpected object type \"" ++ LsTree.typeobj i ++ "\"")
| otherwise = Right (t, i:is)
parseerr = Left
type InTree = LsTree.TreeItem -> Bool
topTree :: InTree
topTree = notElem '/' . getTopFilePath . LsTree.file
subTree :: LsTree.TreeItem -> InTree
subTree t =
let prefix = getTopFilePath (LsTree.file t) ++ "/"
in (\i -> prefix `isPrefixOf` getTopFilePath (LsTree.file i))
|
