Fix build on Windows

[ghc-hetmet.git] / utils / ghc-pkg / Main.hs

diff --git a/utils/ghc-pkg/Main.hs b/utils/ghc-pkg/Main.hs
index 92bcb77..0ac8041 100644 (file)
--- a/utils/ghc-pkg/Main.hs
+++ b/utils/ghc-pkg/Main.hs
@@ -10,7 +10,7 @@
 module Main (main) where
 
 import Version ( version, targetOS, targetARCH )
-import Distribution.InstalledPackageInfo.Binary
+import Distribution.InstalledPackageInfo.Binary()
 import qualified Distribution.Simple.PackageIndex as PackageIndex
 import Distribution.ModuleName hiding (main)
 import Distribution.InstalledPackageInfo
@@ -236,6 +236,13 @@ usageHeader prog = substProg prog $
   "    by tools that parse the results, rather than humans.  The output is\n" ++
   "    always encoded in UTF-8, regardless of the current locale.\n" ++
   "\n" ++
+  "  $p recache\n" ++
+  "    Regenerate the package database cache.  This command should only be\n" ++
+  "    necessary if you added a package to the database by dropping a file\n" ++
+  "    into the database directory manually.  By default, the global DB\n" ++
+  "    is recached; to recache a different DB use --user or --package-conf\n" ++
+  "    as appropriate.\n" ++
+  "\n" ++
   " Substring matching is supported for {module} in find-module and\n" ++
   " for {pkg} in list, describe, and field, where a '*' indicates\n" ++
   " open substring ends (prefix*, *suffix, *infix*).\n" ++
@@ -728,7 +735,7 @@ updateDBCache verbosity db = do
   let filename = location db </> cachefilename
   when (verbosity > Normal) $
       putStrLn ("writing cache " ++ filename)
-  writeBinPackageDB filename (map convertPackageInfoOut (packages db))
+  writeBinaryFileAtomic filename (map convertPackageInfoOut (packages db))
     `catch` \e ->
       if isPermissionError e
       then die (filename ++ ": you don't have permission to modify this file")
@@ -1541,12 +1548,20 @@ catchError io handler = io `Exception.catch` handler'
     where handler' (Exception.ErrorCall err) = handler err
 
 
+writeBinaryFileAtomic :: Bin.Binary a => FilePath -> a -> IO ()
+writeBinaryFileAtomic targetFile obj =
+  withFileAtomic targetFile $ \h -> B.hPutStr h (Bin.encode obj)
+
+writeFileAtomic :: FilePath -> String -> IO ()
+writeFileAtomic targetFile content =
+  withFileAtomic targetFile $ \h -> hPutStr h content
+
 -- copied from Cabal's Distribution.Simple.Utils, except that we want
 -- to use text files here, rather than binary files.
-writeFileAtomic :: FilePath -> String -> IO ()
-writeFileAtomic targetFile content = do
+withFileAtomic :: FilePath -> (Handle -> IO ()) -> IO ()
+withFileAtomic targetFile write_content = do
   (newFile, newHandle) <- openNewFile targetDir template
-  do  hPutStr newHandle content
+  do  write_content newHandle
       hClose newHandle
 #if mingw32_HOST_OS || mingw32_TARGET_OS
       renameFile newFile targetFile