aboutsummaryrefslogtreecommitdiff
path: root/Utility/LogFile.hs
blob: e4f90d41888c83e56730bb26d94a77e58a8712bc (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
{- log files
 -
 - Copyright 2012 Joey Hess <joey@kitenet.net>
 -
 - License: BSD-2-clause
 -}

{-# LANGUAGE CPP #-}

module Utility.LogFile where

import Common

#ifndef mingw32_HOST_OS
import System.Posix.Types
#endif

openLog :: FilePath -> IO Handle
openLog logfile = do
	rotateLog logfile
	openFile logfile AppendMode

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