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+{- misc utility functions
+ -
+ - Copyright 2010-2011 Joey Hess <joey@kitenet.net>
+ -
+ - License: BSD-2-clause
+ -}
+
+{-# LANGUAGE CPP #-}
+
+module Utility.Misc where
+
+import System.IO
+import Control.Monad
+import Foreign
+import Data.Char
+import Data.List
+import Control.Applicative
+import System.Exit
+#ifndef mingw32_HOST_OS
+import System.Posix.Process (getAnyProcessStatus)
+import Utility.Exception
+#endif
+
+import Utility.FileSystemEncoding
+import Utility.Monad
+
+{- 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
+
+{- Reads a file strictly, and using the FileSystemEncoding, so it will
+ - never crash on a badly encoded file. -}
+readFileStrictAnyEncoding :: FilePath -> IO String
+readFileStrictAnyEncoding f = withFile f ReadMode $ \h -> do
+ fileEncoding h
+ hClose h `after` hGetContentsStrict h
+
+{- Writes a file, using the FileSystemEncoding so it will never crash
+ - on a badly encoded content string. -}
+writeFileAnyEncoding :: FilePath -> String -> IO ()
+writeFileAnyEncoding f content = withFile f WriteMode $ \h -> do
+ fileEncoding h
+ hPutStr h content
+
+{- 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 git processes.
+ -
+ - 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 = do
+ -- 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