ghc-mod/Language/Haskell/GhcMod/GHCApi.hs

{-# LANGUAGE ScopedTypeVariables, RecordWildCards #-}

module Language.Haskell.GhcMod.GHCApi (
    initializeFlagsWithCradle
  , setTargetFiles
  , getDynamicFlags
  , systemLibDir
  , withDynFlags
  , withCmdFlags
  , setNoWaringFlags
  , setAllWaringFlags
  , ghcPkgDb
  , package
  , modules
  , findModule
  , moduleInfo
  , localModuleInfo
  , bindings
  ) where

import Language.Haskell.GhcMod.CabalApi
import Language.Haskell.GhcMod.GHCChoice
import Language.Haskell.GhcMod.GhcPkg
import Language.Haskell.GhcMod.DynFlags
import qualified Language.Haskell.GhcMod.Gap as Gap
import Language.Haskell.GhcMod.Types

import Control.Applicative ((<$>))
import Control.Monad (void)
import Distribution.Package (InstalledPackageId(..))
import Data.Maybe (isJust, fromJust)
import qualified Data.Map as M
import GHC (DynFlags(..))
import qualified GHC as G
import GhcMonad
import GHC.Paths (libdir)
import qualified Packages as G
import qualified Module as G
import qualified OccName as G

----------------------------------------------------------------

-- | Obtaining the directory for system libraries.
systemLibDir :: FilePath
systemLibDir = libdir

----------------------------------------------------------------

importDirs :: [IncludeDir]
importDirs = [".","..","../..","../../..","../../../..","../../../../.."]

-- | Initialize the 'DynFlags' relating to the compilation of a single
-- file or GHC session according to the 'Cradle' and 'Options'
-- provided.
initializeFlagsWithCradle :: GhcMonad m
        => Options
        -> Cradle
        -> m ()
initializeFlagsWithCradle opt cradle
  | cabal     = withCabal |||> withSandbox
  | otherwise = withSandbox
  where
    mCradleFile = cradleCabalFile cradle
    cabal = isJust mCradleFile
    ghcopts = ghcOpts opt
    withCabal = do
        pkgDesc <- liftIO $ parseCabalFile $ fromJust mCradleFile
        compOpts <- liftIO $ getCompilerOptions ghcopts cradle pkgDesc
        initSession CabalPkg opt compOpts
    withSandbox = initSession SingleFile opt compOpts
      where
        pkgOpts = ghcDbStackOpts $ cradlePkgDbStack cradle
        compOpts
          | null pkgOpts = CompilerOptions ghcopts importDirs []
          | otherwise    = CompilerOptions (ghcopts ++ pkgOpts) [wdir,rdir] []
        wdir = cradleCurrentDir cradle
        rdir = cradleRootDir    cradle

----------------------------------------------------------------

initSession :: GhcMonad m
            => Build
            -> Options
            -> CompilerOptions
            -> m ()
initSession build Options {..} CompilerOptions {..} = do
    df <- G.getSessionDynFlags
    void $ G.setSessionDynFlags =<< (addCmdOpts ghcOptions
      $ setLinkerOptions
      $ setIncludeDirs includeDirs
      $ setBuildEnv build
      $ setEmptyLogger
      $ Gap.addPackageFlags depPackages df)

----------------------------------------------------------------
-- get Packages,Modules,Bindings

ghcPkgDb :: GhcMonad m => m PkgDb
ghcPkgDb = M.fromList <$>
    maybe [] (map toKv . filterInternal) <$> pkgDatabase <$> G.getSessionDynFlags
 where
    toKv pkg = (fromInstalledPackageId $ G.installedPackageId pkg, pkg)
    filterInternal =
        filter ((/= InstalledPackageId "builtin_rts") . G.installedPackageId)

package :: G.PackageConfig -> Package
package = fromInstalledPackageId . G.installedPackageId

modules :: G.PackageConfig -> [ModuleString]
modules = map G.moduleNameString . G.exposedModules

findModule :: ModuleString -> PkgDb -> [Package]
findModule m db = do
  M.elems $ package `M.map` (containsModule `M.filter` db)
 where
    containsModule :: G.PackageConfig -> Bool
    containsModule pkgConf =
        G.mkModuleName m `elem` G.exposedModules pkgConf


ghcPkgId :: Package -> G.PackageId
ghcPkgId (name,_,_) =
    -- TODO: Adding the package version too breaks 'findModule' for some reason
    -- this isn't a big deal since in the common case where we're in a cabal
    -- project we just use cabal's view of package dependencies anyways so we're
    -- guaranteed to only have one version of each package exposed. However when
    -- we're operating without a cabal project this will probaly cause trouble.
    G.stringToPackageId name

type Binding = String

-- | @moduleInfo mpkg module@. @mpkg@ should be 'Nothing' iff. moduleInfo
-- should look for @module@ in the working directory.
--
-- To map a 'ModuleString' to a package see 'findModule'
moduleInfo :: GhcMonad m
           => Maybe Package
           -> ModuleString
           -> m (Maybe G.ModuleInfo)
moduleInfo mpkg mdl = do
    let mdlName = G.mkModuleName mdl
        mfsPkgId = G.packageIdFS . ghcPkgId <$> mpkg
    loadLocalModule
    G.findModule mdlName mfsPkgId >>= G.getModuleInfo
 where
   loadLocalModule = case mpkg of
       Just _ -> return ()
       Nothing -> setTargetFiles [mdl]

localModuleInfo :: GhcMonad m => ModuleString -> m (Maybe G.ModuleInfo)
localModuleInfo mdl = moduleInfo Nothing mdl

bindings :: G.ModuleInfo -> [Binding]
bindings minfo = do
  map (G.occNameString . G.getOccName) $ G.modInfoExports minfo


----------------------------------------------------------------
-- for PkgDoc

-- import Distribution.InstalledPackageInfo (showInstalledPackageInfoField)
-- haddockHtml :: GhcMonad m => Package -> m String
-- haddockHtml pkg = do
--     extractField info . fromJust . lookup pkg <$> ghcPkgDb
--  where
--     extractField = fromJust $ showInstalledPackageInfoField "haddock-html"