ghc-mod/cabal-helper/Wrapper.hs
Daniel Gröber 52e3233f44 Introducing cabal-helper-wrapper
The idea here is to build cabal-helper with whatever version of Cabal
the user happens to be using (which we find by looking at
dist/setup-config) at runtime.

This way we can support literally any version of Cabal as long as the
actual cabal-helper still compiles.

I tried to only use interfaces in Cabal that have been there since at
least 1.16 so I'm hoping this shouldn't break too much.
2015-03-03 21:06:58 +01:00

259 lines
8.3 KiB
Haskell

-- ghc-mod: Making Haskell development *more* fun
-- Copyright (C) 2015 Daniel Gröber <dxld ÄT darkboxed DOT org>
--
-- This program is free software: you can redistribute it and/or modify
-- it under the terms of the GNU Affero General Public License as published by
-- the Free Software Foundation, either version 3 of the License, or
-- (at your option) any later version.
--
-- This program is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-- GNU Affero General Public License for more details.
--
-- You should have received a copy of the GNU Affero General Public License
-- along with this program. If not, see <http://www.gnu.org/licenses/>.
{-# LANGUAGE TemplateHaskell, OverloadedStrings, RecordWildCards #-}
module Main where
import Control.Applicative
import Control.Arrow
import Control.Monad
import Control.Monad.Trans.Maybe
import Data.Char
import Data.List
import Data.Maybe
import Data.String
import Data.Version
import Data.ByteString (ByteString)
import qualified Data.ByteString as BS
import qualified Data.ByteString.Char8 as BS8
import Text.Printf
import Text.ParserCombinators.ReadP
import System.Environment
import System.Directory
import System.FilePath
import System.Process
import System.Exit
import System.IO
import Distribution.System (buildPlatform)
import Distribution.Text (display)
import NotCPP.Declarations
import Paths_ghc_mod
import Common
import Utils
ifD [d| getExecutablePath = getProgName |]
usage :: IO ()
usage = do
prog <- getProgName
hPutStr stderr $ align "(" "|" ("Usage: " ++ prog ++ " " ++ usageMsg)
where
usageMsg = "\
\( print-appdatadir\n\
\| print-build-platform\n\
\| DIST_DIR [CABAL_HELPER_ARGS...]\n\
\)\n"
main :: IO ()
main = do
args <- getArgs
case args of
"print-appdatadir":[] -> putStrLn =<< appDataDir
"print-build-platform":[] -> putStrLn $ display buildPlatform
distdir:_ -> do
cfgf <- canonicalizePath (distdir </> "setup-config")
mhdr <- (parseHeader =<<) . listToMaybe . BS8.lines <$> BS.readFile cfgf
case mhdr of
Nothing -> error $ printf "\
\Could not read Cabal's persistent setup configuration header\n\
\- Check first line of: %s\n\
\- Maybe try: $ cabal configure" cfgf
Just Header {..} -> do
eexe <- compileHelper hdrCabalVersion
case eexe of
Left e -> exitWith e
Right exe -> do
(_,_,_,h) <- createProcess $ proc exe args
exitWith =<< waitForProcess h
_ -> usage
appDataDir :: IO FilePath
appDataDir = (</> "cabal-helper") <$> getAppUserDataDirectory "ghc-mod"
tryFindSrcDirInGhcModTree :: IO (Maybe FilePath)
tryFindSrcDirInGhcModTree = do
dir <- (!!4) . iterate takeDirectory <$> getExecutablePath
exists <- doesFileExist $ dir </> "ghc-mod.cabal"
src_exists <- doesFileExist $ dir </> "cabal-helper/Main.hs"
if exists && src_exists
then return $ Just (dir </> "cabal-helper")
else return Nothing
tryFindRealSrcDir :: IO (Maybe FilePath)
tryFindRealSrcDir = do
datadir <- getDataDir
exists <- doesFileExist $ datadir </> "cabal-helper/Main.hs"
return $ if exists
then Just $ datadir </> "cabal-helper"
else Nothing
findCabalHelperSourceDir :: IO FilePath
findCabalHelperSourceDir = do
msrcdir <- runMaybeT $ MaybeT tryFindSrcDirInGhcModTree
<|> MaybeT tryFindRealSrcDir
case msrcdir of
Nothing -> getDataDir >>= errorNoMain
Just datadir -> return datadir
compileHelper :: Version -> IO (Either ExitCode FilePath)
compileHelper cabalVer = do
chdir <- findCabalHelperSourceDir
mver <- find (sameMajorVersion cabalVer) <$> listCabalVersions
couldBeSrcDir <- takeDirectory <$> getDataDir
case mver of
Nothing -> do
let cabalFile = couldBeSrcDir </> "Cabal.cabal"
cabal <- doesFileExist cabalFile
if cabal
then do
ver <- cabalFileVersion <$> readFile cabalFile
compile $ Compile chdir (Just couldBeSrcDir) ver []
else errorNoCabal cabalVer
Just ver ->
compile $ Compile chdir Nothing ver [cabalPkgId ver]
where
cabalPkgId v = "Cabal-" ++ showVersion v
errorNoCabal :: Version -> a
errorNoCabal cabalVer = error $ printf "\
\No appropriate Cabal package found, wanted version %s.\n\
\- Check output of: $ ghc-pkg list Cabal\n\
\- Maybe try: $ cabal install Cabal --constraint 'Cabal == %s.*'" sver mjver
where
sver = showVersion cabalVer
mjver = showVersion $ majorVer cabalVer
errorNoMain :: FilePath -> a
errorNoMain datadir = error $ printf "\
\Could not find $datadir/cabal-helper/Main.hs!\n\
\\n\
\If you are a developer you can use the environment variable `ghc_mod_datadir'\n\
\to override $datadir[1], `$ export ghc_mod_datadir=$PWD' will work in the\n\
\ghc-mod tree.\n\
\[1]: %s\n\
\\n\
\If you don't know what I'm talking about something went wrong with your\n\
\installation. Please report this problem here:\n\
\ https://github.com/kazu-yamamoto/ghc-mod/issues" datadir
data Compile = Compile {
cabalHelperSourceDir :: FilePath,
cabalSourceDir :: Maybe FilePath,
cabalVersion :: Version,
packageDeps :: [String]
}
compile :: Compile -> IO (Either ExitCode FilePath)
compile Compile {..} = do
outdir <- appDataDir
createDirectoryIfMissing True outdir
let exe = outdir </> "cabal-helper-" ++ showVersion (majorVer cabalVersion)
recompile <-
case cabalSourceDir of
Nothing -> do
tsrcs <- timeHsFiles cabalHelperSourceDir
texe <- timeMaybe exe
return $ any ((texe <) . Just) tsrcs
Just _ -> return True -- let ghc do the difficult recomp checking
let Version (mj:mi:_) _ = cabalVersion
let ghc_opts =
concat [
[ "-outputdir", outdir
, "-o", exe
, "-optP-DCABAL_MAJOR=" ++ show mj
, "-optP-DCABAL_MINOR=" ++ show mi
],
map ("-i"++) $ cabalHelperSourceDir:maybeToList cabalSourceDir,
concatMap (\p -> ["-package", p]) packageDeps,
[ "--make", cabalHelperSourceDir </> "Main.hs" ]
]
if recompile
then do
(_, _, _, h) <- createProcess
(proc "ghc" ghc_opts) { std_out = UseHandle stderr }
rv <- waitForProcess h
return $ case rv of
ExitSuccess -> Right exe
e@(ExitFailure _) -> Left e
else return $ Right exe
timeHsFiles :: FilePath -> IO [TimedFile]
timeHsFiles dir = do
fs <- map (dir</>) <$> getDirectoryContents dir
mapM timeFile =<< filterM isHsFile fs
where
isHsFile f = do
exists <- doesFileExist f
return $ exists && ".hs" `isSuffixOf` f
-- TODO: Include sandbox? Probably only relevant for build-type:custom projects.
listCabalVersions :: IO [Version]
listCabalVersions = do
catMaybes . map (fmap snd . parsePkgId . fromString) . words
<$> readProcess "ghc-pkg" ["list", "--simple-output", "Cabal"] ""
data Header = Header { hdrCabalVersion :: Version
, hdrCompilerVersion :: Version
}
-- | Find @version: XXX@ delcaration in a cabal file
cabalFileVersion :: String -> Version
cabalFileVersion cabalFile = do
fromJust $ parseVer . extract <$> find ("version" `isPrefixOf`) ls
where
ls = map (map toLower) $ lines cabalFile
extract = dropWhile (/=':') >>> dropWhile isSpace >>> takeWhile (not . isSpace)
parseHeader :: ByteString -> Maybe Header
parseHeader header = case BS8.words header of
["Saved", "package", "config", "for", _pkgId ,
"written", "by", cabalId,
"using", compId]
-> liftM2 Header (ver cabalId) (ver compId)
_ -> error "parsing setup-config header failed"
where
ver i = snd <$> parsePkgId i
parsePkgId :: ByteString -> Maybe (ByteString, Version)
parsePkgId bs =
case BS8.split '-' bs of
[pkg, vers] -> Just (pkg, parseVer $ BS8.unpack vers)
_ -> Nothing
parseVer :: String -> Version
parseVer vers = runReadP parseVersion vers
majorVer :: Version -> Version
majorVer (Version b _) = Version (take 2 b) []
sameMajorVersion :: Version -> Version -> Bool
sameMajorVersion a b = majorVer a == majorVer b
runReadP :: ReadP t -> String -> t
runReadP p i = let (a,""):[] = filter ((=="") . snd) $ readP_to_S p i in a