[commit: Cabal] master: Refactor to avoid problems when $HOME is not set (cbe5067)

[Ian Lynagh]

Repository : ssh://darcs.haskell.org//srv/darcs/packages/Cabal

On branch  : master

http://hackage.haskell.org/trac/ghc/changeset/cbe506729799b8f44506559b6ba47644b0d75d2c

>---------------------------------------------------------------

commit cbe506729799b8f44506559b6ba47644b0d75d2c
Author: Ian Lynagh <igloo at earth.li>
Date:   Sun Apr 17 15:41:35 2011 +0000

    Refactor to avoid problems when $HOME is not set
    We now avoid calling getWindowsProgramFilesDir and
    getAppUserDataDirectory when we don't need to know their results.
    This means that a GHC build goes through when $HOME is unset
    (GHC trac #5047).

>---------------------------------------------------------------

 Distribution/Simple/InstallDirs.hs |   28 +++++++++++++++-------------
 1 files changed, 15 insertions(+), 13 deletions(-)

diff --git a/Distribution/Simple/InstallDirs.hs b/Distribution/Simple/InstallDirs.hs
index 1d7fb95..b9b240f 100644
--- a/Distribution/Simple/InstallDirs.hs
+++ b/Distribution/Simple/InstallDirs.hs
@@ -217,21 +217,23 @@ type InstallDirTemplates = InstallDirs PathTemplate
 
 defaultInstallDirs :: CompilerFlavor -> Bool -> Bool -> IO InstallDirTemplates
 defaultInstallDirs comp userInstall _hasLibs = do
-  windowsProgramFilesDir <- getWindowsProgramFilesDir
-  userInstallPrefix      <- getAppUserDataDirectory "cabal"
-  lhcPrefix              <- getAppUserDataDirectory "lhc"
+  installPrefix <-
+      if userInstall
+      then getAppUserDataDirectory "cabal"
+      else case buildOS of
+           Windows -> do windowsProgramFilesDir <- getWindowsProgramFilesDir
+                         return (windowsProgramFilesDir </> "Haskell")
+           _       -> return "/usr/local"
+  installLibDir <-
+      case buildOS of
+      Windows -> return "$prefix"
+      _       -> case comp of
+                 LHC | userInstall -> getAppUserDataDirectory "lhc"
+                 _                 -> return ("$prefix" </> "lib")
   return $ fmap toPathTemplate $ InstallDirs {
-      prefix       = if userInstall
-                       then userInstallPrefix
-                       else case buildOS of
-        Windows   -> windowsProgramFilesDir </> "Haskell"
-        _other    -> "/usr/local",
+      prefix       = installPrefix,
       bindir       = "$prefix" </> "bin",
-      libdir       = case buildOS of
-        Windows   -> "$prefix"
-        _other    -> case comp of
-                       LHC | userInstall -> lhcPrefix
-                       _                 -> "$prefix" </> "lib",
+      libdir       = installLibDir,
       libsubdir    = case comp of
            Hugs   -> "hugs" </> "packages" </> "$pkg"
            JHC    -> "$compiler"