git-annex/Utility.hs
Joey Hess 6a9a9bd5a3 another memory optimisation
This time memory leaked if lots of UUIDs needed to be pretty-printed, as in
a get or drop of many files. Essentially the same strict read buffering
problem that affected the LocationLog underneath though.

uuidMap really could stand to be cached, as the uuid log is read many times
in this case. But it is a fairly edge case.
2010-10-31 01:51:50 -04:00

119 lines
3.4 KiB
Haskell

{- git-annex utility functions
-
- Copyright 2010 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Utility (
hGetContentsStrict,
parentDir,
relPathCwdToDir,
relPathDirToDir,
boolSystem,
shellEscape
) where
import System.IO
import System.Cmd.Utils
import System.Exit
import System.Posix.Process
import System.Posix.Process.Internals
import System.Posix.Signals
import System.Posix.IO
import Data.String.Utils
import System.Path
import System.IO.HVFS
import System.FilePath
import System.Directory
{- A version of hgetContents that is not lazy. Ensures file is
- all read before it gets closed. -}
hGetContentsStrict h = hGetContents h >>= \s -> length s `seq` return s
{- Returns the parent directory of a path. Parent of / is "" -}
parentDir :: String -> String
parentDir dir =
if (not $ null dirs)
then slash ++ (join s $ take ((length dirs) - 1) dirs)
else ""
where
dirs = filter (\x -> length x > 0) $
split s dir
slash = if (not $ isAbsolute dir) then "" else s
s = [pathSeparator]
{- Constructs a relative path from the CWD to a directory.
-
- For example, assuming CWD is /tmp/foo/bar:
- relPathCwdToDir "/tmp/foo" == "../"
- relPathCwdToDir "/tmp/foo/bar" == ""
- relPathCwdToDir "/tmp/foo/bar" == ""
-}
relPathCwdToDir :: FilePath -> IO FilePath
relPathCwdToDir dir = do
cwd <- getCurrentDirectory
let absdir = abs cwd dir
return $ relPathDirToDir cwd absdir
where
-- absolute, normalized form of the directory
abs cwd dir =
case (absNormPath cwd dir) of
Just d -> d
Nothing -> error $ "unable to normalize " ++ dir
{- Constructs a relative path from one directory to another.
-
- Both directories must be absolute, and normalized (eg with absNormpath).
-
- The path will end with "/", unless it is empty.
-}
relPathDirToDir :: FilePath -> FilePath -> FilePath
relPathDirToDir from to =
if (not $ null path)
then addTrailingPathSeparator path
else ""
where
s = [pathSeparator]
pfrom = split s from
pto = split s to
common = map fst $ filter same $ zip pfrom pto
same (c,d) = c == d
uncommon = drop numcommon pto
dotdots = take ((length pfrom) - numcommon) $ repeat ".."
numcommon = length $ common
path = join s $ dotdots ++ uncommon
{- Run a system command, and returns True or False
- if it succeeded or failed.
-
- SIGINT(ctrl-c) is allowed to propigate and will terminate the program.
-}
boolSystem :: FilePath -> [String] -> IO Bool
boolSystem command params = do
-- Going low-level because all the high-level system functions
-- block SIGINT etc. We need to block SIGCHLD, but allow
-- SIGINT to do its default program termination.
let sigset = addSignal sigCHLD emptySignalSet
oldint <- installHandler sigINT Default Nothing
oldset <- getSignalMask
blockSignals sigset
childpid <- forkProcess $ childaction oldint oldset
mps <- getProcessStatus True False childpid
restoresignals oldint oldset
case mps of
Just (Exited ExitSuccess) -> return True
_ -> return False
where
restoresignals oldint oldset = do
installHandler sigINT oldint Nothing
setSignalMask oldset
childaction oldint oldset = do
restoresignals oldint oldset
executeFile command True params Nothing
{- Escapes a filename to be safely able to be exposed to the shell. -}
shellEscape f = "'" ++ quote ++ "'"
where
-- replace ' with '"'"'
quote = join "'\"'\"'" $ split "'" f