{-# OPTIONS -O2 -Wall #-}
{-# LANGUAGE FlexibleContexts, RecordWildCards #-}
import Control.Applicative ((<$>))
import qualified Control.Exception as E
import Control.Monad (when, unless)
import Control.Monad.State (MonadState, state, evalStateT)
import Control.Monad.Writer (runWriter, tell)
import Data.Algorithm.Diff (Diff, getDiff)
import Data.List (isPrefixOf, isSuffixOf)
import Data.Maybe (mapMaybe)
import Data.Monoid (Monoid(..))
import qualified Data.Monoid as Monoid
import PPDiff (ppDiff, ColorEnable(..))
import System.Directory (renameFile, removeFile)
import System.Environment (getProgName, getArgs, getEnv)
import System.Exit (ExitCode(..))
import System.FilePath ((<.>), (</>))
import System.Posix.IO (stdOutput)
import System.Posix.Terminal (queryTerminal)
import System.Process (callProcess, readProcess, readProcessWithExitCode)
data Side = A | B
deriving (Eq, Ord, Show)
type LineNo = Int
data Conflict = Conflict
{ _lineNo :: LineNo
, _markerA :: String -- <<<<<<<....
, _markerBase :: String -- |||||||....
, _markerB :: String -- =======....
, _markerEnd :: String -- >>>>>>>....
, _linesA :: [String]
, _linesBase :: [String]
, _linesB :: [String]
} deriving (Show)
prettyConflict :: Conflict -> String
prettyConflict (Conflict _ markerA markerBase markerB markerEnd linesA linesBase linesB) =
unlines $ concat
[ markerA : linesA
, markerBase : linesBase
, markerB : linesB
, [markerEnd]
]
resolveConflict :: Conflict -> Maybe String
resolveConflict Conflict{..}
| _linesA == _linesBase = Just $ unlines _linesB
| _linesB == _linesBase = Just $ unlines _linesA
| _linesA == _linesB = Just $ unlines _linesA
| otherwise = Nothing
breakUpToMarker :: MonadState [(LineNo, String)] m => Char -> m [(LineNo, String)]
breakUpToMarker c = state (break ((replicate 7 c `isPrefixOf`) . snd))
readHead :: MonadState [a] m => m (Maybe a)
readHead = state f
where
f [] = (Nothing, [])
f (l:ls) = (Just l, ls)
readUpToMarker :: MonadState [(LineNo, String)] m => Char -> m ([(LineNo, String)], Maybe (LineNo, String))
readUpToMarker c =
do
ls <- breakUpToMarker c
mHead <- readHead
return (ls, mHead)
parseConflict :: MonadState [(LineNo, String)] m => LineNo -> String -> m Conflict
parseConflict lineNo markerA = do
(linesA , Just (_, markerBase)) <- readUpToMarker '|'
(linesBase, Just (_, markerB)) <- readUpToMarker '='
(linesB , Just (_, markerEnd)) <- readUpToMarker '>'
return Conflict
{ _lineNo = lineNo
, _markerA = markerA
, _markerBase = markerBase
, _markerB = markerB
, _markerEnd = markerEnd
, _linesA = map snd linesA
, _linesB = map snd linesB
, _linesBase = map snd linesBase
}
parseConflicts :: String -> [Either String Conflict]
parseConflicts input =
snd $ runWriter $ evalStateT loop (zip [1..] (lines input))
where
loop =
do
(ls, mMarkerA) <- readUpToMarker '<'
tell $ map (Left . snd) ls
case mMarkerA of
Nothing -> return ()
Just (lineNo, markerA) ->
do
tell . return . Right =<< parseConflict lineNo markerA
loop
type SideDiff = (Side, LineNo, [Diff String])
data NewContent = NewContent
{ _resolvedSuccessfully :: Int
, _failedToResolve :: Int
, _newContent :: String
, _diffs :: [SideDiff]
}
getConflictDiffs :: Conflict -> [SideDiff]
getConflictDiffs Conflict{..} =
[ (A, _lineNo, getDiff _linesBase _linesA) | not (null _linesA) ] ++
[ (B, _lineNo, getDiff _linesBase _linesB) | not (null _linesB) ]
resolveContent :: [Either String Conflict] -> NewContent
resolveContent = asResult . mconcat . map go
where
asResult (Monoid.Sum successes, Monoid.Sum failures, newContent, diffs) = NewContent
{ _resolvedSuccessfully = successes
, _failedToResolve = failures
, _newContent = newContent
, _diffs = diffs
}
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
, getConflictDiffs 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, diff) =
do
putStrLn $ filePath ++ ":" ++ show lineNo ++ ":Diff" ++ show side
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
resolve :: ColorEnable -> Options -> FilePath -> IO ()
resolve colorEnable opts fileName =
do
content <- parseConflicts <$> readFile fileName
case resolveContent content of
NewContent successes failures newContent diffs
| 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" ]
dumpAndOpenEditor colorEnable opts fileName diffs
| otherwise ->
do
putStrLn $ concat
[ fileName, ": Successfully resolved ", show successes
, " conflicts (failed to resolve " ++ show failures ++ " conflicts)"
, if failures == 0 then ", git adding" else ""
]
let bkup = fileName <.> "bk"
renameFile fileName bkup
writeFile fileName newContent
removeFile bkup
if failures == 0
then gitAdd fileName
else dumpAndOpenEditor colorEnable opts fileName diffs
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?"
]
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
let rootRelativeFileNames =
mapMaybe (unprefix "UU ") $ lines statusPorcelain
rootDir <- stripNewline <$> readProcess "git" ["rev-parse", "--show-toplevel"] stdin
mapM_ (resolve colorEnable opts .
(rootDir </>)) rootRelativeFileNames