git-annex/Utility/Misc.hs
Joey Hess 8526cd7c92
test: Avoid most situations involving failure to delete test directories
By forking a worker process and only deleting the test directory once it exits.

This way, if a test leaves files open, they'll get closed when the worker
exits, so avoiding failure to delete open files on Windows, and failure to
delete directories due to NFS lock files.

If a test leaves a git worker process running, the closed pipes should
cause the worker to exit too, also avoiding the problem there. The 10
second sleep ought to give plenty of time for such worker processes to
exit, although this is of course a race.

Finally, even if test directory fails to be deleted still,
it won't appear as if the last test in the test suite failed; the error
will be displayed at the very end.

This commit was supported by the NSF-funded DataLad project.
2017-08-14 16:29:47 -04:00

133 lines
3.9 KiB
Haskell

{- misc utility functions
-
- Copyright 2010-2011 Joey Hess <id@joeyh.name>
-
- License: BSD-2-clause
-}
{-# LANGUAGE CPP #-}
{-# OPTIONS_GHC -fno-warn-tabs #-}
module Utility.Misc where
import System.IO
import Control.Monad
import Foreign
import Data.Char
import Data.List
import System.Exit
#ifndef mingw32_HOST_OS
import System.Posix.Process (getAnyProcessStatus)
import Utility.Exception
#endif
import Control.Applicative
import Prelude
{- A version of hgetContents that is not lazy. Ensures file is
- all read before it gets closed. -}
hGetContentsStrict :: Handle -> IO String
hGetContentsStrict = hGetContents >=> \s -> length s `seq` return s
{- A version of readFile that is not lazy. -}
readFileStrict :: FilePath -> IO String
readFileStrict = readFile >=> \s -> length s `seq` return s
{- Like break, but the item matching the condition is not included
- in the second result list.
-
- separate (== ':') "foo:bar" = ("foo", "bar")
- separate (== ':') "foobar" = ("foobar", "")
-}
separate :: (a -> Bool) -> [a] -> ([a], [a])
separate c l = unbreak $ break c l
where
unbreak r@(a, b)
| null b = r
| otherwise = (a, tail b)
{- Breaks out the first line. -}
firstLine :: String -> String
firstLine = takeWhile (/= '\n')
{- Splits a list into segments that are delimited by items matching
- a predicate. (The delimiters are not included in the segments.)
- Segments may be empty. -}
segment :: (a -> Bool) -> [a] -> [[a]]
segment p l = map reverse $ go [] [] l
where
go c r [] = reverse $ c:r
go c r (i:is)
| p i = go [] (c:r) is
| otherwise = go (i:c) r is
prop_segment_regressionTest :: Bool
prop_segment_regressionTest = all id
-- Even an empty list is a segment.
[ segment (== "--") [] == [[]]
-- There are two segements in this list, even though the first is empty.
, segment (== "--") ["--", "foo", "bar"] == [[],["foo","bar"]]
]
{- Includes the delimiters as segments of their own. -}
segmentDelim :: (a -> Bool) -> [a] -> [[a]]
segmentDelim p l = map reverse $ go [] [] l
where
go c r [] = reverse $ c:r
go c r (i:is)
| p i = go [] ([i]:c:r) is
| otherwise = go (i:c) r is
{- Replaces multiple values in a string.
-
- Takes care to skip over just-replaced values, so that they are not
- mangled. For example, massReplace [("foo", "new foo")] does not
- replace the "new foo" with "new new foo".
-}
massReplace :: [(String, String)] -> String -> String
massReplace vs = go [] vs
where
go acc _ [] = concat $ reverse acc
go acc [] (c:cs) = go ([c]:acc) vs cs
go acc ((val, replacement):rest) s
| val `isPrefixOf` s =
go (replacement:acc) vs (drop (length val) s)
| otherwise = go acc rest s
{- Wrapper around hGetBufSome that returns a String.
-
- The null string is returned on eof, otherwise returns whatever
- data is currently available to read from the handle, or waits for
- data to be written to it if none is currently available.
-
- Note on encodings: The normal encoding of the Handle is ignored;
- each byte is converted to a Char. Not unicode clean!
-}
hGetSomeString :: Handle -> Int -> IO String
hGetSomeString h sz = do
fp <- mallocForeignPtrBytes sz
len <- withForeignPtr fp $ \buf -> hGetBufSome h buf sz
map (chr . fromIntegral) <$> withForeignPtr fp (peekbytes len)
where
peekbytes :: Int -> Ptr Word8 -> IO [Word8]
peekbytes len buf = mapM (peekElemOff buf) [0..pred len]
{- Reaps any zombie processes that may be hanging around.
-
- Warning: Not thread safe. Anything that was expecting to wait
- on a process and get back an exit status is going to be confused
- if this reap gets there first. -}
reapZombies :: IO ()
#ifndef mingw32_HOST_OS
reapZombies =
-- throws an exception when there are no child processes
catchDefaultIO Nothing (getAnyProcessStatus False True)
>>= maybe (return ()) (const reapZombies)
#else
reapZombies = return ()
#endif
exitBool :: Bool -> IO a
exitBool False = exitFailure
exitBool True = exitSuccess