{-# OPTIONS -O2 -Wall #-}
{-# LANGUAGE NoImplicitPrelude, FlexibleContexts, RecordWildCards, LambdaCase #-}
module Main (main) where
import qualified Control.Exception as E
import Control.Monad (when, unless, filterM)
import Control.Monad.State (MonadState, state, evalStateT)
import Control.Monad.Writer (runWriter, tell)
import Data.Algorithm.Diff (Diff, getDiff)
import Data.Foldable (asum, traverse_)
import Data.List (isPrefixOf, isSuffixOf)
import Data.Maybe (mapMaybe)
import qualified Data.Monoid as Monoid
import PPDiff (ppDiff, ColorEnable(..))
import System.Directory (renameFile, removeFile, getCurrentDirectory)
import System.Environment (getProgName, getArgs, getEnv)
import System.Exit (ExitCode(..))
import System.FilePath ((<.>), makeRelative, joinPath, splitPath)
import qualified System.FilePath as FilePath
import qualified System.Posix.Files as PosixFiles
import System.Posix.IO (stdOutput)
import System.Posix.Terminal (queryTerminal)
import System.Process (callProcess, readProcess, readProcessWithExitCode)
import Prelude.Compat
data Side = A | B
deriving (Eq, Ord, Show)
type LineNo = Int
data Conflict = Conflict
{ cMarkerA :: (LineNo, String) -- <<<<<<<....
, cMarkerBase :: (LineNo, String) -- |||||||....
, cMarkerB :: (LineNo, String) -- =======....
, cMarkerEnd :: (LineNo, String) -- >>>>>>>....
, cLinesA :: [String]
, cLinesBase :: [String]
, cLinesB :: [String]
} deriving (Show)
prettyConflict :: Conflict -> String
prettyConflict Conflict {..} =
unlines $ concat
[ snd cMarkerA : cLinesA
, snd cMarkerBase : cLinesBase
, snd cMarkerB : cLinesB
, [snd cMarkerEnd]
]
resolveConflict :: Conflict -> Maybe String
resolveConflict Conflict{..}
| cLinesA == cLinesBase = Just $ unlines cLinesB
| cLinesB == cLinesBase = Just $ unlines cLinesA
| cLinesA == cLinesB = Just $ unlines cLinesA
| otherwise = Nothing
-- '>' -> ">>>>>>> "
markerPrefix :: Char -> String
markerPrefix = replicate 7
markerLine :: Char -> String -> String
markerLine c str = markerPrefix c ++ " " ++ str ++ "\n"
breakUpToMarker :: MonadState [(LineNo, String)] m => Char -> m [(LineNo, String)]
breakUpToMarker c = state (break ((markerPrefix c `isPrefixOf`) . snd))
readHead :: MonadState [a] m => m (Maybe a)
readHead = state f
where
f [] = (Nothing, [])
f (l:ls) = (Just l, ls)
tryReadUpToMarker :: MonadState [(LineNo, String)] m => Char -> m ([(LineNo, String)], Maybe (LineNo, String))
tryReadUpToMarker c =
do
ls <- breakUpToMarker c
mHead <- readHead
return (ls, mHead)
readUpToMarker :: MonadState [(LineNo, String)] m => Char -> m ([(LineNo, String)], (LineNo, String))
readUpToMarker c = do
res <- tryReadUpToMarker c
case res of
(ls, Just h) -> return (ls, h)
(ls, Nothing) ->
error $ concat
[ "Parse error: failed reading up to marker: "
, show c, ", got:"
, concatMap (\(l,s) -> "\n" ++ show l ++ "\t" ++ s) $ take 5 ls
]
parseConflict :: MonadState [(LineNo, String)] m => (LineNo, String) -> m Conflict
parseConflict markerA =
do (linesA , markerBase) <- readUpToMarker '|'
(linesBase, markerB) <- readUpToMarker '='
(linesB , markerEnd) <- readUpToMarker '>'
return Conflict
{ cMarkerA = markerA
, cMarkerBase = markerBase
, cMarkerB = markerB
, cMarkerEnd = markerEnd
, cLinesA = map snd linesA
, cLinesB = map snd linesB
, cLinesBase = map snd linesBase
}
parseConflicts :: String -> [Either String Conflict]
parseConflicts input =
snd $ runWriter $ evalStateT loop (zip [1..] (lines input))
where
loop =
do (ls, mMarkerA) <- tryReadUpToMarker '<'
tell $ map (Left . snd) ls
case mMarkerA of
Nothing -> return ()
Just markerA ->
do tell . return . Right =<< parseConflict markerA
loop
type SideDiff = (Side, (LineNo, String), [Diff String])
data NewContent = NewContent
{ _resolvedSuccessfully :: Int
, _failedToResolve :: Int
, _newContent :: String
}
getConflictDiffs :: Conflict -> [SideDiff]
getConflictDiffs Conflict{..} =
[ (A, cMarkerA, getDiff cLinesBase cLinesA) | not (null cLinesA) ] ++
[ (B, (fst cMarkerB, snd cMarkerEnd), getDiff cLinesBase cLinesB) | not (null cLinesB) ]
resolveContent :: [Either String Conflict] -> NewContent
resolveContent = asResult . mconcat . map go
where
asResult (Monoid.Sum successes, Monoid.Sum failures, newContent) =
NewContent
{ _resolvedSuccessfully = successes
, _failedToResolve = failures
, _newContent = newContent
}
go (Left line) = (Monoid.Sum 0, Monoid.Sum 0, unlines [line])
go (Right conflict) =
case resolveConflict conflict of
Nothing -> (Monoid.Sum 0, Monoid.Sum 1, prettyConflict conflict)
Just trivialLines -> (Monoid.Sum 1, Monoid.Sum 0, trivialLines)
gitAdd :: FilePath -> IO ()
gitAdd fileName =
callProcess "git" ["add", "--", fileName]
data Options = Options
{ shouldUseEditor :: Bool
, shouldDumpDiffs :: Bool
, shouldUseColor :: Maybe ColorEnable
, shouldSetConflictStyle :: Bool
}
instance Monoid Options where
mempty = Options False False Nothing False
Options oe0 od0 oc0 os0 `mappend` Options oe1 od1 oc1 os1 =
Options
(combineBool oe0 oe1 "-e")
(combineBool od0 od1 "-d")
(combineMaybe oc0 oc1 "-c or -C")
(os0 || os1)
where
err flag = error $ "Multiple " ++ flag ++ " flags used"
combineMaybe (Just _) (Just _) flag = err flag
combineMaybe Nothing Nothing _ = Nothing
combineMaybe (Just x) Nothing _ = Just x
combineMaybe Nothing (Just y) _ = Just y
combineBool True True flag = err flag
combineBool x y _ = x || y
getOpts :: [String] -> IO Options
getOpts = fmap mconcat . mapM parseArg
where
parseArg "-e" = return mempty { shouldUseEditor = True }
parseArg "-d" = return mempty { shouldDumpDiffs = True }
parseArg "-c" = return mempty { shouldUseColor = Just EnableColor }
parseArg "-C" = return mempty { shouldUseColor = Just DisableColor }
parseArg "-s" = return mempty { shouldSetConflictStyle = True }
parseArg arg =
do prog <- getProgName
putStr $ unlines
[ "Usage: " ++ prog ++ " [-e] [-d] [-c] [-C] [-s]"
, ""
, "-e Execute $EDITOR for each conflicted file that remains conflicted"
, "-d Dump the left/right diffs from base in each conflict remaining"
, "-c Enable color"
, "-C Disable color"
, "-s Configure git's global merge.conflictstyle to diff3 if needed"
]
fail $ "Unknown argument: " ++ show arg
openEditor :: Options -> FilePath -> IO ()
openEditor opts path
| shouldUseEditor opts =
do editor <- getEnv "EDITOR"
callProcess editor [path]
| otherwise = return ()
dumpDiffs :: ColorEnable -> Options -> FilePath -> [SideDiff] -> IO ()
dumpDiffs colorEnable opts filePath diffs
| shouldDumpDiffs opts = mapM_ dumpDiff diffs
| otherwise = return ()
where
dumpDiff (side, (lineNo, marker), diff) =
do putStrLn $ concat
[filePath, ":", show lineNo, ":Diff", show side, ": ", marker]
putStr $ unlines $ map (ppDiff colorEnable) diff
dumpAndOpenEditor :: ColorEnable -> Options -> FilePath -> [SideDiff] -> IO ()
dumpAndOpenEditor colorEnable opts path diffs =
do dumpDiffs colorEnable opts path diffs
openEditor opts path
overwrite :: FilePath -> String -> IO ()
overwrite fileName newContent =
do renameFile fileName bkup
writeFile fileName newContent
removeFile bkup
where
bkup = fileName <.> "bk"
resolve :: ColorEnable -> Options -> FilePath -> IO ()
resolve colorEnable opts fileName =
resolveContent . parseConflicts <$> readFile fileName
>>= \case
NewContent successes failures newContent
| successes == 0 && failures == 0 ->
do putStrLn $ fileName ++ ": No conflicts, git-adding"
gitAdd fileName
| successes == 0 ->
do putStrLn $ concat
[ fileName, ": Failed to resolve any of the "
, show failures, " conflicts" ]
doDump
| otherwise ->
do putStrLn $ concat
[ fileName, ": Successfully resolved ", show successes
, " conflicts (failed to resolve " ++ show failures ++ " conflicts)"
, if failures == 0 then ", git adding" else ""
]
overwrite fileName newContent
if failures == 0
then gitAdd fileName
else doDump
where
doDump =
dumpAndOpenEditor colorEnable opts fileName
[ cDiff
| Right conflict <- parseConflicts newContent
, cDiff <- getConflictDiffs conflict
]
stripNewline :: String -> String
stripNewline x
| "\n" `isSuffixOf` x = init x
| otherwise = x
shouldUseColorByTerminal :: IO ColorEnable
shouldUseColorByTerminal =
do istty <- queryTerminal stdOutput
return $ if istty then EnableColor else DisableColor
unprefix :: Eq a => [a] -> [a] -> Maybe [a]
unprefix prefix str
| prefix `isPrefixOf` str = Just (drop (length prefix) str)
| otherwise = Nothing
getConflictStyle :: IO String
getConflictStyle =
do (exitCode, stdout, _) <- readProcessWithExitCode "git" ["config", "merge.conflictstyle"] stdin
case exitCode of
ExitSuccess -> return $ stripNewline stdout
ExitFailure 1 -> return "unset"
ExitFailure _ -> E.throwIO exitCode
where
stdin = ""
setConflictStyle :: IO ()
setConflictStyle =
callProcess "git" ["config", "--global", "merge.conflictstyle", "diff3"]
checkConflictStyle :: Options -> IO ()
checkConflictStyle opts =
do conflictStyle <- getConflictStyle
when (conflictStyle /= "diff3") $
do unless (shouldSetConflictStyle opts) $
fail $ concat
[ "merge.conflictstyle must be diff3 but is "
, show conflictStyle
, ". Use -s to automatically set it globally"
]
setConflictStyle
newConflictStyle <- getConflictStyle
when (newConflictStyle /= "diff3") $
fail $ concat
[ "Attempt to set conflict style failed. Perhaps you have"
, " an incorrect merge.conflictstyle configuration "
, "specified in your per-project .git/config?"
]
relativePath :: FilePath -> FilePath -> FilePath
relativePath base path
| rel /= path = rel
| revRel /= base =
joinPath $ replicate (length (splitPath revRel)) ".."
| otherwise = path
where
rel = makeRelative base path
revRel = makeRelative path base
(</>) :: FilePath -> FilePath -> FilePath
"." </> p = p
d </> p = d FilePath.</> p
isDirectory :: FilePath -> IO Bool
isDirectory x = PosixFiles.isDirectory <$> PosixFiles.getFileStatus x
ensureNewline :: String -> String
ensureNewline "" = ""
ensureNewline str = str ++ suffix
where
suffix
| "\n" `isSuffixOf` str = ""
| otherwise = "\n"
withAllStageFiles ::
FilePath -> (FilePath -> Maybe FilePath -> Maybe FilePath -> IO b) -> IO b
withAllStageFiles path action =
do let stdin = ""
[baseTmp, localTmp, remoteTmp] <-
take 3 . words <$>
readProcess "git" ["checkout-index", "--stage=all", "--", path] stdin
let maybePath "." = Nothing
maybePath p = Just p
let mLocalTmp = maybePath localTmp
mRemoteTmp = maybePath remoteTmp
action baseTmp mLocalTmp mRemoteTmp
`E.finally`
do removeFile baseTmp
traverse_ removeFile mLocalTmp
traverse_ removeFile mRemoteTmp
deleteModifyConflictAddMarkers :: FilePath -> IO ()
deleteModifyConflictAddMarkers path =
withAllStageFiles path $ \baseTmp mLocalTmp mRemoteTmp ->
do baseContent <- readFile baseTmp
localContent <- maybe (return "") readFile mLocalTmp
remoteContent <- maybe (return "") readFile mRemoteTmp
overwrite path $
concat
[ markerLine '<' "LOCAL"
, ensureNewline localContent
, markerLine '|' "BASE"
, ensureNewline baseContent
, markerLine '=' ""
, ensureNewline remoteContent
, markerLine '>' "REMOTE"
]
deleteModifyConflictHandle :: FilePath -> IO ()
deleteModifyConflictHandle path =
do marked <- any (markerPrefix '<' `isPrefixOf`) . lines <$> readFile path
unless marked $
do putStrLn $ show path ++ " has a delete/modify conflict. Adding conflict markers"
deleteModifyConflictAddMarkers path
removeFileIfEmpty :: FilePath -> IO ()
removeFileIfEmpty path =
do isEmpty <- null <$> readFile path
when isEmpty $
do removeFile path
callProcess "git" ["add", "-u", "--", path]
main :: IO ()
main =
do opts <- getOpts =<< getArgs
colorEnable <-
case shouldUseColor opts of
Nothing -> shouldUseColorByTerminal
Just colorEnable -> return colorEnable
checkConflictStyle opts
let stdin = ""
statusPorcelain <- readProcess "git" ["status", "--porcelain"] stdin
cwd <- getCurrentDirectory
rootDir <-
relativePath cwd . stripNewline <$>
readProcess "git" ["rev-parse", "--show-toplevel"] stdin
let rootRelativeFiles =
filterM (fmap not . isDirectory) . map (rootDir </>)
let firstMatchingPrefix :: [String] -> String -> Maybe String
firstMatchingPrefix prefixes =
asum . traverse unprefix prefixes
let filesMatchingPrefixes :: [String] -> IO [FilePath]
filesMatchingPrefixes prefixes =
rootRelativeFiles . mapMaybe (firstMatchingPrefix prefixes)
$ lines statusPorcelain
-- from git-diff manpage:
-- Added (A), Copied (C), Deleted (D), Modified (M), Renamed (R),
-- have their type (i.e. regular file, symlink, submodule, ...) changed (T),
-- are Unmerged (U), are Unknown (X), or have had their pairing Broken (B)
deleteModifyConflicts <- filesMatchingPrefixes ["DU ", "UD "]
mapM_ deleteModifyConflictHandle deleteModifyConflicts
filesMatchingPrefixes ["UU ", "AA ", "DA ", "AD ", "DU ", "UD "]
>>= mapM_ (resolve colorEnable opts)
-- Heuristically delete files that were remove/modify conflict
-- and ended up with empty content
mapM_ removeFileIfEmpty deleteModifyConflicts