git-annex/Utility/LogFile.hs
2014-02-25 14:48:50 -04:00

62 lines
1.2 KiB
Haskell

{- log files
-
- Copyright 2012 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
{-# LANGUAGE CPP #-}
module Utility.LogFile where
import Common
#ifndef mingw32_HOST_OS
import System.Posix.Types
#endif
#ifndef mingw32_HOST_OS
openLog :: FilePath -> IO Fd
openLog logfile = do
rotateLog logfile
openFd logfile WriteOnly (Just stdFileMode)
defaultFileFlags { append = True }
#endif
rotateLog :: FilePath -> IO ()
rotateLog logfile = go 0
where
go num
| num > maxLogs = return ()
| otherwise = whenM (doesFileExist currfile) $ do
go (num + 1)
rename currfile nextfile
where
currfile = filename num
nextfile = filename (num + 1)
filename n
| n == 0 = logfile
| otherwise = rotatedLog logfile n
rotatedLog :: FilePath -> Int -> FilePath
rotatedLog logfile n = logfile ++ "." ++ show n
{- Lists most recent logs last. -}
listLogs :: FilePath -> IO [FilePath]
listLogs logfile = filterM doesFileExist $ reverse $
logfile : map (rotatedLog logfile) [1..maxLogs]
maxLogs :: Int
maxLogs = 9
#ifndef mingw32_HOST_OS
redirLog :: Fd -> IO ()
redirLog logfd = do
mapM_ (redir logfd) [stdOutput, stdError]
closeFd logfd
redir :: Fd -> Fd -> IO ()
redir newh h = do
closeFd h
void $ dupTo newh h
#endif