ghc-boot-9.14.1: GHC/Unit/Database.hs
{-# OPTIONS_GHC -fno-warn-name-shadowing #-}
{-# LANGUAGE CPP #-}
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE DeriveTraversable #-}
{-# LANGUAGE LambdaCase #-}
{-# LANGUAGE GADTs #-}
{-# LANGUAGE KindSignatures #-}
{-# LANGUAGE StandaloneDeriving #-}
{-# LANGUAGE TupleSections #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE TypeSynonymInstances #-}
{-# LANGUAGE ExplicitNamespaces #-}
{-# LANGUAGE RecordWildCards #-}
{-# LANGUAGE OverloadedStrings #-}
-----------------------------------------------------------------------------
-- |
-- Module : GHC.Unit.Database
-- Copyright : (c) The University of Glasgow 2009, Duncan Coutts 2014
--
-- Maintainer : ghc-devs@haskell.org
-- Portability : portable
--
-- This module provides the view of GHC's database of registered packages that
-- is shared between GHC the compiler\/library, and the ghc-pkg program. It
-- defines the database format that is shared between GHC and ghc-pkg.
--
-- The database format, and this library are constructed so that GHC does not
-- have to depend on the Cabal library. The ghc-pkg program acts as the
-- gateway between the external package format (which is defined by Cabal) and
-- the internal package format which is specialised just for GHC.
--
-- GHC the compiler only needs some of the information which is kept about
-- registered packages, such as module names, various paths etc. On the other
-- hand ghc-pkg has to keep all the information from Cabal packages and be able
-- to regurgitate it for users and other tools.
--
-- The first trick is that we duplicate some of the information in the package
-- database. We essentially keep two versions of the database in one file, one
-- version used only by ghc-pkg which keeps the full information (using the
-- serialised form of the 'InstalledPackageInfo' type defined by the Cabal
-- library); and a second version written by ghc-pkg and read by GHC which has
-- just the subset of information that GHC needs.
--
-- The second trick is that this module only defines in detail the format of
-- the second version -- the bit GHC uses -- and the part managed by ghc-pkg
-- is kept in the file but here we treat it as an opaque blob of data. That way
-- this library avoids depending on Cabal.
--
module GHC.Unit.Database
( GenericUnitInfo(..)
, type DbUnitInfo
, DbModule (..)
, DbInstUnitId (..)
, mapGenericUnitInfo
-- * Read and write
, DbMode(..)
, DbOpenMode(..)
, isDbOpenReadMode
, readPackageDbForGhc
, readPackageDbForGhcPkg
, writePackageDb
-- * Locking
, PackageDbLock
, lockPackageDb
, unlockPackageDb
-- * Misc
, mkMungePathUrl
, mungeUnitInfoPaths
)
where
import Prelude -- See note [Why do we import Prelude here?]
import Data.Version (Version(..))
import qualified Data.ByteString as BS
import qualified Data.ByteString.Char8 as BS.Char8
import qualified Data.ByteString.Lazy as BS.Lazy
import qualified Data.ByteString.Lazy.Internal as BS.Lazy (defaultChunkSize)
import qualified Data.Foldable as F
import qualified Data.Traversable as F
import Data.Bifunctor
import Data.Binary as Bin
import Data.Binary.Put as Bin
import Data.Binary.Get as Bin
import Data.List (intersperse)
import Control.Exception as Exception
import Control.Monad (when)
import System.FilePath as FilePath
#if !defined(mingw32_HOST_OS)
import Data.Bits ((.|.))
import System.Posix.Files
import System.Posix.Types (FileMode)
#endif
import System.IO
import System.IO.Error
import GHC.IO.Exception (IOErrorType(InappropriateType))
import qualified GHC.Data.ShortText as ST
import GHC.IO.Handle.Lock
import System.Directory
-- | @ghc-boot@'s UnitInfo, serialized to the database.
type DbUnitInfo = GenericUnitInfo BS.ByteString BS.ByteString BS.ByteString BS.ByteString DbModule
-- | Information about an unit (a unit is an installed module library).
--
-- This is a subset of Cabal's 'InstalledPackageInfo', with just the bits
-- that GHC is interested in.
--
-- Some types are left as parameters to be instantiated differently in ghc-pkg
-- and in ghc itself.
--
data GenericUnitInfo srcpkgid srcpkgname uid modulename mod = GenericUnitInfo
{ unitId :: uid
-- ^ Unique unit identifier that is used during compilation (e.g. to
-- generate symbols).
, unitInstanceOf :: uid
-- ^ Identifier of an indefinite unit (i.e. with module holes) that this
-- unit is an instance of.
--
-- For non instantiated units, unitInstanceOf=unitId
, unitInstantiations :: [(modulename, mod)]
-- ^ How this unit instantiates some of its module holes. Map hole module
-- names to actual module
, unitPackageId :: srcpkgid
-- ^ Source package identifier.
--
-- Cabal instantiates this with Distribution.Types.PackageId.PackageId
-- type which only contains the source package name and version. Notice
-- that it doesn't contain the Hackage revision, nor any kind of hash.
, unitPackageName :: srcpkgname
-- ^ Source package name
, unitPackageVersion :: Version
-- ^ Source package version
, unitComponentName :: Maybe srcpkgname
-- ^ Name of the component.
--
-- Cabal supports more than one components (libraries, executables,
-- testsuites) in the same package. Each component has a name except the
-- default one (that can only be a library component) for which we use
-- "Nothing".
--
-- GHC only deals with "library" components as they are the only kind of
-- components that can be registered in a database and used by other
-- modules.
, unitAbiHash :: ST.ShortText
-- ^ ABI hash used to avoid mixing up units compiled with different
-- dependencies, compiler, options, etc.
, unitDepends :: [uid]
-- ^ Identifiers of the units this one depends on
, unitAbiDepends :: [(uid, ST.ShortText)]
-- ^ Like 'unitDepends', but each dependency is annotated with the ABI hash
-- we expect the dependency to respect.
, unitImportDirs :: [FilePathST]
-- ^ Directories containing module interfaces
, unitLibraries :: [ST.ShortText]
-- ^ Names of the Haskell libraries provided by this unit
, unitExtDepLibsSys :: [ST.ShortText]
-- ^ Names of the external system libraries that this unit depends on. See
-- also `unitExtDepLibsGhc` field.
, unitExtDepLibsGhc :: [ST.ShortText]
-- ^ Because of slight differences between the GHC dynamic linker (in
-- GHC.Runtime.Linker) and the
-- native system linker, some packages have to link with a different list
-- of libraries when using GHC's. Examples include: libs that are actually
-- gnu ld scripts, and the possibility that the .a libs do not exactly
-- match the .so/.dll equivalents.
--
-- If this field is set, then we use that instead of the
-- `unitExtDepLibsSys` field.
, unitLibraryDirs :: [FilePathST]
-- ^ Directories containing libraries provided by this unit. See also
-- `unitLibraryDynDirs`.
--
-- It seems to be used to store paths to external library dependencies
-- too.
, unitLibraryDynDirs :: [FilePathST]
-- ^ Directories containing the dynamic libraries provided by this unit.
-- See also `unitLibraryDirs`.
--
-- It seems to be used to store paths to external dynamic library
-- dependencies too.
, unitExtDepFrameworks :: [ST.ShortText]
-- ^ Names of the external MacOS frameworks that this unit depends on.
, unitExtDepFrameworkDirs :: [FilePathST]
-- ^ Directories containing MacOS frameworks that this unit depends
-- on.
, unitLinkerOptions :: [ST.ShortText]
-- ^ Linker (e.g. ld) command line options
, unitCcOptions :: [ST.ShortText]
-- ^ C compiler options that needs to be passed to the C compiler when we
-- compile some C code against this unit.
, unitIncludes :: [ST.ShortText]
-- ^ C header files that are required by this unit (provided by this unit
-- or external)
, unitIncludeDirs :: [FilePathST]
-- ^ Directories containing C header files that this unit depends
-- on.
, unitHaddockInterfaces :: [FilePathST]
-- ^ Paths to Haddock interface files for this unit
, unitHaddockHTMLs :: [FilePathST]
-- ^ Paths to Haddock directories containing HTML files
, unitExposedModules :: [(modulename, Maybe mod)]
-- ^ Modules exposed by the unit.
--
-- A module can be re-exported from another package. In this case, we
-- indicate the module origin in the second parameter.
, unitHiddenModules :: [modulename]
-- ^ Hidden modules.
--
-- These are useful for error reporting (e.g. if a hidden module is
-- imported)
, unitIsIndefinite :: Bool
-- ^ True if this unit has some module holes that need to be instantiated
-- with real modules to make the unit usable (a.k.a. Backpack).
, unitIsExposed :: Bool
-- ^ True if the unit is exposed. A unit could be installed in a database
-- by "disabled" by not being exposed.
, unitIsTrusted :: Bool
-- ^ True if the unit is trusted (cf Safe Haskell)
}
deriving (Eq, Show)
type FilePathST = ST.ShortText
-- | Convert between GenericUnitInfo instances
mapGenericUnitInfo
:: (uid1 -> uid2)
-> (srcpkg1 -> srcpkg2)
-> (srcpkgname1 -> srcpkgname2)
-> (modname1 -> modname2)
-> (mod1 -> mod2)
-> (GenericUnitInfo srcpkg1 srcpkgname1 uid1 modname1 mod1
-> GenericUnitInfo srcpkg2 srcpkgname2 uid2 modname2 mod2)
mapGenericUnitInfo fuid fsrcpkg fsrcpkgname fmodname fmod g@(GenericUnitInfo {..}) =
g { unitId = fuid unitId
, unitInstanceOf = fuid unitInstanceOf
, unitInstantiations = fmap (bimap fmodname fmod) unitInstantiations
, unitPackageId = fsrcpkg unitPackageId
, unitPackageName = fsrcpkgname unitPackageName
, unitComponentName = fmap fsrcpkgname unitComponentName
, unitDepends = fmap fuid unitDepends
, unitAbiDepends = fmap (first fuid) unitAbiDepends
, unitExposedModules = fmap (bimap fmodname (fmap fmod)) unitExposedModules
, unitHiddenModules = fmap fmodname unitHiddenModules
}
-- | @ghc-boot@'s 'Module', serialized to the database.
data DbModule
= DbModule
{ dbModuleUnitId :: DbInstUnitId
, dbModuleName :: BS.ByteString
}
| DbModuleVar
{ dbModuleVarName :: BS.ByteString
}
deriving (Eq, Show)
-- | @ghc-boot@'s instantiated unit id, serialized to the database.
data DbInstUnitId
-- | Instantiated unit
= DbInstUnitId
BS.ByteString -- component id
[(BS.ByteString, DbModule)] -- instantiations: [(modulename,module)]
-- | Uninstantiated unit
| DbUnitId
BS.ByteString -- unit id
deriving (Eq, Show)
-- | Represents a lock of a package db.
newtype PackageDbLock = PackageDbLock Handle
-- | Acquire an exclusive lock related to package DB under given location.
lockPackageDb :: FilePath -> IO PackageDbLock
-- | Release the lock related to package DB.
unlockPackageDb :: PackageDbLock -> IO ()
-- | Acquire a lock of given type related to package DB under given location.
lockPackageDbWith :: LockMode -> FilePath -> IO PackageDbLock
lockPackageDbWith mode file = do
-- We are trying to open the lock file and then lock it. Thus the lock file
-- needs to either exist or we need to be able to create it. Ideally we
-- would not assume that the lock file always exists in advance. When we are
-- dealing with a package DB where we have write access then if the lock
-- file does not exist then we can create it by opening the file in
-- read/write mode. On the other hand if we are dealing with a package DB
-- where we do not have write access (e.g. a global DB) then we can only
-- open in read mode, and the lock file had better exist already or we're in
-- trouble. So for global read-only DBs on platforms where we must lock the
-- DB for reading then we will require that the installer/packaging has
-- included the lock file.
--
-- Thus the logic here is to first try opening in read-write mode
-- and if that fails we try read-only (to handle global read-only DBs).
-- If either succeed then lock the file. IO exceptions (other than the first
-- open attempt failing due to the file not existing) simply propagate.
--
-- Note that there is a complexity here which was discovered in #13945: some
-- filesystems (e.g. NFS) will only allow exclusive locking if the fd was
-- opened for write access. We would previously try opening the lockfile for
-- read-only access first, however this failed when run on such filesystems.
-- Consequently, we now try read-write access first, falling back to read-only
-- if we are denied permission (e.g. in the case of a global database).
catchJust
(\e -> if isPermissionError e then Just () else Nothing)
(lockFileOpenIn ReadWriteMode)
(const $ lockFileOpenIn ReadMode)
where
lock = file <.> "lock"
lockFileOpenIn io_mode = bracketOnError
(openBinaryFile lock io_mode)
hClose
-- If file locking support is not available, ignore the error and proceed
-- normally. Without it the only thing we lose on non-Windows platforms is
-- the ability to safely issue concurrent updates to the same package db.
$ \hnd -> do hLock hnd mode `catch` \FileLockingNotSupported -> return ()
return $ PackageDbLock hnd
lockPackageDb = lockPackageDbWith ExclusiveLock
unlockPackageDb (PackageDbLock hnd) = do
hUnlock hnd
hClose hnd
-- | Mode to open a package db in.
data DbMode = DbReadOnly | DbReadWrite
-- | 'DbOpenMode' holds a value of type @t@ but only in 'DbReadWrite' mode. So
-- it is like 'Maybe' but with a type argument for the mode to enforce that the
-- mode is used consistently.
data DbOpenMode (mode :: DbMode) t where
DbOpenReadOnly :: DbOpenMode 'DbReadOnly t
DbOpenReadWrite :: t -> DbOpenMode 'DbReadWrite t
deriving instance Functor (DbOpenMode mode)
deriving instance F.Foldable (DbOpenMode mode)
deriving instance F.Traversable (DbOpenMode mode)
isDbOpenReadMode :: DbOpenMode mode t -> Bool
isDbOpenReadMode = \case
DbOpenReadOnly -> True
DbOpenReadWrite{} -> False
-- | Read the part of the package DB that GHC is interested in.
--
readPackageDbForGhc :: FilePath -> IO [DbUnitInfo]
readPackageDbForGhc file =
decodeFromFile file DbOpenReadOnly getDbForGhc >>= \case
(pkgs, DbOpenReadOnly) -> return pkgs
where
getDbForGhc = do
_version <- getHeader
_ghcPartLen <- get :: Get Word32
ghcPart <- get
-- the next part is for ghc-pkg, but we stop here.
return ghcPart
-- | Read the part of the package DB that ghc-pkg is interested in
--
-- Note that the Binary instance for ghc-pkg's representation of packages
-- is not defined in this package. This is because ghc-pkg uses Cabal types
-- (and Binary instances for these) which this package does not depend on.
--
-- If we open the package db in read only mode, we get its contents. Otherwise
-- we additionally receive a PackageDbLock that represents a lock on the
-- database, so that we can safely update it later.
--
readPackageDbForGhcPkg :: Binary pkgs => FilePath -> DbOpenMode mode t ->
IO (pkgs, DbOpenMode mode PackageDbLock)
readPackageDbForGhcPkg file mode =
decodeFromFile file mode getDbForGhcPkg
where
getDbForGhcPkg = do
_version <- getHeader
-- skip over the ghc part
ghcPartLen <- get :: Get Word32
_ghcPart <- skip (fromIntegral ghcPartLen)
-- the next part is for ghc-pkg
ghcPkgPart <- get
return ghcPkgPart
-- | Write the whole of the package DB, both parts.
--
writePackageDb :: Binary pkgs => FilePath -> [DbUnitInfo] -> pkgs -> IO ()
writePackageDb file ghcPkgs ghcPkgPart = do
writeFileAtomic file (runPut putDbForGhcPkg)
#if !defined(mingw32_HOST_OS)
addFileMode file 0o444
-- ^ In case the current umask is too restrictive force all read bits to
-- allow access.
#endif
return ()
where
putDbForGhcPkg = do
putHeader
put ghcPartLen
putLazyByteString ghcPart
put ghcPkgPart
where
ghcPartLen :: Word32
ghcPartLen = fromIntegral (BS.Lazy.length ghcPart)
ghcPart = encode ghcPkgs
#if !defined(mingw32_HOST_OS)
addFileMode :: FilePath -> FileMode -> IO ()
addFileMode file m = do
o <- fileMode <$> getFileStatus file
setFileMode file (m .|. o)
#endif
getHeader :: Get (Word32, Word32)
getHeader = do
magic <- getByteString (BS.length headerMagic)
when (magic /= headerMagic) $
fail "not a ghc-pkg db file, wrong file magic number"
majorVersion <- get :: Get Word32
-- The major version is for incompatible changes
minorVersion <- get :: Get Word32
-- The minor version is for compatible extensions
when (majorVersion /= 1) $
fail "unsupported ghc-pkg db format version"
-- If we ever support multiple major versions then we'll have to change
-- this code
-- The header can be extended without incrementing the major version,
-- we ignore fields we don't know about (currently all).
headerExtraLen <- get :: Get Word32
skip (fromIntegral headerExtraLen)
return (majorVersion, minorVersion)
putHeader :: Put
putHeader = do
putByteString headerMagic
put majorVersion
put minorVersion
put headerExtraLen
where
majorVersion = 1 :: Word32
minorVersion = 0 :: Word32
headerExtraLen = 0 :: Word32
headerMagic :: BS.ByteString
headerMagic = BS.Char8.pack "\0ghcpkg\0"
-- TODO: we may be able to replace the following with utils from the binary
-- package in future.
-- | Feed a 'Get' decoder with data chunks from a file.
--
decodeFromFile :: FilePath -> DbOpenMode mode t -> Get pkgs ->
IO (pkgs, DbOpenMode mode PackageDbLock)
decodeFromFile file mode decoder = case mode of
DbOpenReadOnly -> do
-- Note [Locking package database on Windows]
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-- When we open the package db in read only mode, there is no need to acquire
-- shared lock on non-Windows platform because we update the database with an
-- atomic rename, so readers will always see the database in a consistent
-- state.
#if defined(mingw32_HOST_OS)
bracket (lockPackageDbWith SharedLock file) unlockPackageDb $ \_ -> do
#endif
(, DbOpenReadOnly) <$> decodeFileContents
DbOpenReadWrite{} -> do
-- When we open the package db in read/write mode, acquire an exclusive lock
-- on the database and return it so we can keep it for the duration of the
-- update.
bracketOnError (lockPackageDb file) unlockPackageDb $ \lock -> do
(, DbOpenReadWrite lock) <$> decodeFileContents
where
decodeFileContents = withBinaryFile file ReadMode $ \hnd ->
feed hnd (runGetIncremental decoder)
feed hnd (Partial k) = do chunk <- BS.hGet hnd BS.Lazy.defaultChunkSize
if BS.null chunk
then feed hnd (k Nothing)
else feed hnd (k (Just chunk))
feed _ (Done _ _ res) = return res
feed _ (Fail _ _ msg) = ioError err
where
err = mkIOError InappropriateType loc Nothing (Just file)
`ioeSetErrorString` msg
loc = "GHC.Unit.Database.readPackageDb"
-- Copied from Cabal's Distribution.Simple.Utils.
writeFileAtomic :: FilePath -> BS.Lazy.ByteString -> IO ()
writeFileAtomic targetPath content = do
let (targetDir, targetFile) = splitFileName targetPath
Exception.bracketOnError
(openBinaryTempFileWithDefaultPermissions targetDir $ targetFile <.> "tmp")
(\(tmpPath, handle) -> hClose handle >> removeFile tmpPath)
(\(tmpPath, handle) -> do
BS.Lazy.hPut handle content
hClose handle
renameFile tmpPath targetPath)
instance Binary DbUnitInfo where
put (GenericUnitInfo
unitId unitInstanceOf unitInstantiations
unitPackageId
unitPackageName unitPackageVersion
unitComponentName
unitAbiHash unitDepends unitAbiDepends unitImportDirs
unitLibraries unitExtDepLibsSys unitExtDepLibsGhc
unitLibraryDirs unitLibraryDynDirs
unitExtDepFrameworks unitExtDepFrameworkDirs
unitLinkerOptions unitCcOptions
unitIncludes unitIncludeDirs
unitHaddockInterfaces unitHaddockHTMLs
unitExposedModules unitHiddenModules
unitIsIndefinite unitIsExposed unitIsTrusted) = do
put unitPackageId
put unitPackageName
put unitPackageVersion
put unitComponentName
put unitId
put unitInstanceOf
put unitInstantiations
put unitAbiHash
put unitDepends
put unitAbiDepends
put unitImportDirs
put unitLibraries
put unitExtDepLibsSys
put unitExtDepLibsGhc
put unitLibraryDirs
put unitLibraryDynDirs
put unitExtDepFrameworks
put unitExtDepFrameworkDirs
put unitLinkerOptions
put unitCcOptions
put unitIncludes
put unitIncludeDirs
put unitHaddockInterfaces
put unitHaddockHTMLs
put unitExposedModules
put unitHiddenModules
put unitIsIndefinite
put unitIsExposed
put unitIsTrusted
get = do
unitPackageId <- get
unitPackageName <- get
unitPackageVersion <- get
unitComponentName <- get
unitId <- get
unitInstanceOf <- get
unitInstantiations <- get
unitAbiHash <- get
unitDepends <- get
unitAbiDepends <- get
unitImportDirs <- get
unitLibraries <- get
unitExtDepLibsSys <- get
unitExtDepLibsGhc <- get
libraryDirs <- get
libraryDynDirs <- get
frameworks <- get
frameworkDirs <- get
unitLinkerOptions <- get
unitCcOptions <- get
unitIncludes <- get
unitIncludeDirs <- get
unitHaddockInterfaces <- get
unitHaddockHTMLs <- get
unitExposedModules <- get
unitHiddenModules <- get
unitIsIndefinite <- get
unitIsExposed <- get
unitIsTrusted <- get
return (GenericUnitInfo
unitId
unitInstanceOf
unitInstantiations
unitPackageId
unitPackageName
unitPackageVersion
unitComponentName
unitAbiHash
unitDepends
unitAbiDepends
unitImportDirs
unitLibraries unitExtDepLibsSys unitExtDepLibsGhc
libraryDirs libraryDynDirs
frameworks frameworkDirs
unitLinkerOptions unitCcOptions
unitIncludes unitIncludeDirs
unitHaddockInterfaces unitHaddockHTMLs
unitExposedModules
unitHiddenModules
unitIsIndefinite unitIsExposed unitIsTrusted)
instance Binary DbModule where
put (DbModule dbModuleUnitId dbModuleName) = do
putWord8 0
put dbModuleUnitId
put dbModuleName
put (DbModuleVar dbModuleVarName) = do
putWord8 1
put dbModuleVarName
get = do
b <- getWord8
case b of
0 -> DbModule <$> get <*> get
_ -> DbModuleVar <$> get
instance Binary DbInstUnitId where
put (DbUnitId uid) = do
putWord8 0
put uid
put (DbInstUnitId dbUnitIdComponentId dbUnitIdInsts) = do
putWord8 1
put dbUnitIdComponentId
put dbUnitIdInsts
get = do
b <- getWord8
case b of
0 -> DbUnitId <$> get
_ -> DbInstUnitId <$> get <*> get
-- | Return functions to perform path/URL variable substitution as per the Cabal
-- ${pkgroot} spec
-- (http://www.haskell.org/pipermail/libraries/2009-May/011772.html)
--
-- Paths/URLs can be relative to ${pkgroot} or ${pkgrooturl}.
-- The "pkgroot" is the directory containing the package database.
--
-- Also perform a similar substitution for the older GHC-specific
-- "$topdir" variable. The "topdir" is the location of the ghc
-- installation (obtained from the -B option).
mkMungePathUrl :: FilePathST -> FilePathST -> (FilePathST -> FilePathST, FilePathST -> FilePathST)
mkMungePathUrl top_dir pkgroot = (munge_path, munge_url)
where
munge_path p
| Just p' <- stripVarPrefix "${pkgroot}" p = mappend pkgroot p'
| Just p' <- stripVarPrefix "$topdir" p = mappend top_dir p'
| otherwise = p
munge_url p
| Just p' <- stripVarPrefix "${pkgrooturl}" p = toUrlPath pkgroot p'
| Just p' <- stripVarPrefix "$httptopdir" p = toUrlPath top_dir p'
| otherwise = p
toUrlPath r p = mconcat $ "file:///" : (intersperse "/" (r : (splitDirectories p)))
-- URLs always use posix style '/' separators
-- We need to drop a leading "/" or "\\" if there is one:
splitDirectories :: FilePathST -> [FilePathST]
splitDirectories p = filter (not . ST.null) $ ST.splitFilePath p
-- We could drop the separator here, and then use </> above. However,
-- by leaving it in and using ++ we keep the same path separator
-- rather than letting FilePath change it to use \ as the separator
stripVarPrefix var path = case ST.stripPrefix var path of
Just "" -> Just ""
Just cs | isPathSeparator (ST.head cs) -> Just cs
_ -> Nothing
-- | Perform path/URL variable substitution as per the Cabal ${pkgroot} spec
-- (http://www.haskell.org/pipermail/libraries/2009-May/011772.html)
-- Paths/URLs can be relative to ${pkgroot} or ${pkgrooturl}.
-- The "pkgroot" is the directory containing the package database.
--
-- Also perform a similar substitution for the older GHC-specific
-- "$topdir" variable. The "topdir" is the location of the ghc
-- installation (obtained from the -B option).
mungeUnitInfoPaths :: FilePathST -> FilePathST -> GenericUnitInfo a b c d e -> GenericUnitInfo a b c d e
mungeUnitInfoPaths top_dir pkgroot pkg =
-- TODO: similar code is duplicated in utils/ghc-pkg/Main.hs
pkg
{ unitImportDirs = munge_paths (unitImportDirs pkg)
, unitIncludeDirs = munge_paths (unitIncludeDirs pkg)
, unitLibraryDirs = munge_paths (unitLibraryDirs pkg)
, unitLibraryDynDirs = munge_paths (unitLibraryDynDirs pkg)
, unitExtDepFrameworkDirs = munge_paths (unitExtDepFrameworkDirs pkg)
, unitHaddockInterfaces = munge_paths (unitHaddockInterfaces pkg)
-- haddock-html is allowed to be either a URL or a file
, unitHaddockHTMLs = munge_paths (munge_urls (unitHaddockHTMLs pkg))
}
where
munge_paths = map munge_path
munge_urls = map munge_url
(munge_path,munge_url) = mkMungePathUrl top_dir pkgroot