    -----------------------------------------------------------------------------
    -- |
    -- Module      :  Distribution.Simple.BuildPaths
    -- Copyright   :  Isaac Jones 2003-2004,
    --                Duncan Coutts 2008
    --
    -- Maintainer  :  cabal-devel@haskell.org
    -- Portability :  portable
    --
    -- A bunch of dirs, paths and file names used for intermediate build steps.
    --

    {- All rights reserved.

    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions are
    met:

        * Redistributions of source code must retain the above copyright
          notice, this list of conditions and the following disclaimer.

        * Redistributions in binary form must reproduce the above
          copyright notice, this list of conditions and the following
          disclaimer in the documentation and/or other materials provided
          with the distribution.

        * Neither the name of Isaac Jones nor the names of other
          contributors may be used to endorse or promote products derived
          from this software without specific prior written permission.

    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
    A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
    OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
    SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
    LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. -}

    module Distribution.Simple.BuildPaths (
        defaultDistPref, srcPref,
        hscolourPref, haddockPref,
        autogenModulesDir,

        autogenModuleName,
        cppHeaderName,
        haddockName,

        mkLibName,
        mkProfLibName,
        mkSharedLibName,

        exeExtension,
        objExtension,
        dllExtension,

      ) where

    import System.FilePath (FilePath, (</>), (<.>))

    import Distribution.Package
             ( PackageIdentifier, packageName )
    import Distribution.ModuleName (ModuleName)
    import qualified Distribution.ModuleName as ModuleName
    import Distribution.Compiler
             ( CompilerId(..) )
    import Distribution.PackageDescription (PackageDescription)
    import Distribution.Simple.LocalBuildInfo (LocalBuildInfo(buildDir))
    import Distribution.Simple.Setup (defaultDistPref)
    import Distribution.Text
             ( display )
    import Distribution.System (OS(..), buildOS)

    -- ---------------------------------------------------------------------------
    -- Build directories and files

    srcPref :: FilePath -> FilePath
    srcPref distPref = distPref </> "src"

    hscolourPref :: FilePath -> PackageDescription -> FilePath
    hscolourPref = haddockPref

    haddockPref :: FilePath -> PackageDescription -> FilePath
    haddockPref distPref pkg_descr
        = distPref </> "doc" </> "html" </> display (packageName pkg_descr)

    -- |The directory in which we put auto-generated modules
    autogenModulesDir :: LocalBuildInfo -> String
    autogenModulesDir lbi = buildDir lbi </> "autogen"

    cppHeaderName :: String
    cppHeaderName = "cabal_macros.h"

    -- |The name of the auto-generated module associated with a package
    autogenModuleName :: PackageDescription -> ModuleName
    autogenModuleName pkg_descr =
      ModuleName.simple $ "Paths_" ++ map fixchar (display (packageName pkg_descr))
      where fixchar '-' = '_'
            fixchar c   = c

    haddockName :: PackageDescription -> FilePath
    haddockName pkg_descr = display (packageName pkg_descr) <.> "haddock"

    -- ---------------------------------------------------------------------------
    -- Library file names

    mkLibName :: PackageIdentifier -> String
    mkLibName lib = "libHS" ++ display lib <.> "a"

    mkProfLibName :: PackageIdentifier -> String
    mkProfLibName lib =  "libHS" ++ display lib ++ "_p" <.> "a"

    -- Implement proper name mangling for dynamical shared objects
    -- libHS<packagename>-<compilerFlavour><compilerVersion>
    -- e.g. libHSbase-2.1-ghc6.6.1.so
    mkSharedLibName :: PackageIdentifier -> CompilerId -> String
    mkSharedLibName lib (CompilerId compilerFlavor compilerVersion)
      = "libHS" ++ display lib ++ "-" ++ comp <.> dllExtension
      where comp = display compilerFlavor ++ display compilerVersion

    -- ------------------------------------------------------------
    -- * Platform file extensions
    -- ------------------------------------------------------------

    -- ToDo: This should be determined via autoconf (AC_EXEEXT)
    -- | Extension for executable files
    -- (typically @\"\"@ on Unix and @\"exe\"@ on Windows or OS\/2)
    exeExtension :: String
    exeExtension = case buildOS of
                       Windows -> "exe"
                       _       -> ""

    -- ToDo: This should be determined via autoconf (AC_OBJEXT)
    -- | Extension for object files. For GHC and NHC the extension is @\"o\"@.
    -- Hugs uses either @\"o\"@ or @\"obj\"@ depending on the used C compiler.
    objExtension :: String
    objExtension = "o"

    -- | Extension for dynamically linked (or shared) libraries
    -- (typically @\"so\"@ on Unix and @\"dll\"@ on Windows)
    dllExtension :: String
    dllExtension = case buildOS of
                       Windows -> "dll"
                       OSX     -> "dylib"
                       _       -> "so"