{- Shell Equivalents Copyright (C) 2004-2009 John Goerzen Please see the COPYRIGHT file -} {- | Module : HSH.ShellEquivs Copyright : Copyright (C) 2009 John Goerzen License : GNU LGPL, version 2.1 or above Maintainer : John Goerzen Stability : provisional Portability: portable Copyright (c) 2006-2009 John Goerzen, jgoerzen\@complete.org This module provides shell-like commands. Most, but not all, are designed to be used directly as part of a HSH pipeline. All may be used outside HSH entirely as well. -} #if !(defined(mingw32_HOST_OS) || defined(mingw32_TARGET_OS) || defined(__MINGW32__)) #define __HSH_POSIX__ #else #define __HSH_WINDOWS__ #endif module HSH.ShellEquivs( abspath, appendTo, basename, bracketCD, catFrom, catBytes, catBytesFrom, catTo, #ifdef __HSH_POSIX__ catToFIFO, #endif cd, cut, cutR, dirname, discard, echo, exit, glob, grep, grepV, egrep, egrepV, joinLines, lower, upper, mkdir, numberLines, pwd, #ifdef __HSH_POSIX__ readlink, readlinkabs, #endif rev, revW, HSH.Command.setenv, space, unspace, tac, tee, #ifdef __HSH_POSIX__ teeFIFO, #endif tr, trd, wcW, wcL, HSH.Command.unsetenv, uniq, ) where import Data.List (genericLength, intersperse, isInfixOf, nub) import Data.Char (toLower, toUpper) import Text.Regex (matchRegex, mkRegex) import Text.Printf (printf) import Control.Monad (foldM) import System.Directory hiding (createDirectory) import Control.Exception(evaluate) -- import System.FilePath (splitPath) #ifdef __HSH_POSIX__ import System.Posix.Files (getFileStatus, isSymbolicLink, readSymbolicLink) import System.Posix.User (getEffectiveUserName, getUserEntryForName, homeDirectory) import System.Posix.Directory (createDirectory) import System.Posix.Types (FileMode()) import System.Posix.IO import System.Posix.Error #endif import System.Path (absNormPath, bracketCWD) import System.Exit import System.IO import System.Process import qualified System.Directory as SD import qualified System.Path.Glob as Glob (glob) import qualified Data.ByteString.Lazy as BSL import qualified Data.ByteString as BS import System.IO.Unsafe(unsafeInterleaveIO) import HSH.Channel import HSH.Command(setenv, unsetenv) {- | Return the absolute path of the arg. Raises an error if the computation is impossible. -} abspath :: FilePath -> IO FilePath abspath inp = do p <- pwd case absNormPath p inp of Nothing -> fail $ "Cannot make " ++ show inp ++ " absolute within " ++ show p Just x -> return x {- | The filename part of a path -} basename :: FilePath -> FilePath basename = snd . splitpath {- | The directory part of a path -} dirname :: FilePath -> FilePath dirname = fst . splitpath {- | Changes the current working directory to the given path, executes the given I\/O action, then changes back to the original directory, even if the I\/O action raised an exception. This is an alias for the MissingH function System.Path.bracketCWD. -} bracketCD :: FilePath -> IO a -> IO a bracketCD = bracketCWD {- | Load the specified files and display them, one at a time. The special file @-@ means to display the input. If it is not given, no input is processed at all. @-@ may be given a maximum of one time. See also 'catBytes' . -} catFrom :: [FilePath] -> Channel -> IO Channel catFrom fplist ichan = do r <- foldM foldfunc BSL.empty fplist return (toChannel r) where foldfunc accum fp = case fp of "-" -> do c <- chanAsBSL ichan return (BSL.append accum c) fn -> do c <- BSL.readFile fn return (BSL.append accum c) {- | Copy data from input to output, optionally with a fixed maximum size, in bytes. Processes data using ByteStrings internally, so be aware of any possible UTF-8 conversions. You may wish to use @hSetBuffering h (BlockBuffering Nothing)@ prior to calling this function for optimal performance. See also 'catFrom', 'catBytesFrom' -} catBytes :: (Maybe Integer) -- ^ Maximum amount of data to transfer -> Channel -- ^ Handle for input -> IO Channel catBytes count hr = catBytesFrom hr count hr {- | Generic version of 'catBytes'; reads data from specified Channel, and ignores stdin. -} catBytesFrom :: Channel -- ^ Handle to read from -> (Maybe Integer) -- ^ Maximum amount of data to transfer -> Channel -- ^ Handle for input (ignored) -> IO Channel catBytesFrom (ChanHandle hr) count cignore = case count of Nothing -> return (ChanHandle hr) Just m -> do c <- BSL.hGet hr (fromIntegral m) return (ChanBSL c) catBytesFrom cinput count cignore = case count of Nothing -> return cinput Just m -> do r <- chanAsBSL cinput return (ChanBSL (BSL.take (fromIntegral m) r)) {- | Takes input, writes it to the specified file, and does not pass it on. The return value is the empty string. See also 'catToBS', 'catToFIFO' -} catTo :: FilePath -> Channel -> IO Channel catTo fp ichan = do ofile <- openFile fp WriteMode chanToHandle ichan ofile hClose ofile return (ChanString "") #ifdef __HSH_POSIX__ {- | Like 'catTo', but opens the destination in ReadWriteMode instead of ReadOnlyMode. Due to an oddity of the Haskell IO system, this is required when writing to a named pipe (FIFO) even if you will never read from it. This call will BLOCK all threads on open until a reader connects. This is provided in addition to 'catTo' because you may want to cat to something that you do not have permission to read from. This function is only available on POSIX platforms. See also 'catTo' -} catToFIFO :: FilePath -> Channel -> IO Channel catToFIFO fp ichan = do h <- fifoOpen fp chanToHandle ichan h hClose h return (ChanString "") fifoOpen :: FilePath -> IO Handle fifoOpen fp = do fd <- throwErrnoPathIf (< 0) "HSH fifoOpen" fp $ openFd fp WriteOnly Nothing defaultFileFlags fdToHandle fd #endif {- | Like 'catTo', but appends to the file. -} appendTo :: FilePath -> String -> IO String appendTo fp inp = do appendFile fp inp return "" {- | An alias for System.Directory.setCurrentDirectory. Want to change to a user\'s home directory? Try this: > glob "~jgoerzen" >>= cd . head See also 'bracketCD'. -} cd :: FilePath -> IO () cd = setCurrentDirectory {- | Split a list by a given character and select the nth list. > cut ' ' 2 "foo bar baz quux" -> "bar" -} cut :: Integer -> Char -> String -> String cut pos = cutR [pos] {- | Read all input and produce no output. Discards input completely. -} discard :: Channel -> IO Channel discard inh = do c <- chanAsBSL inh evaluate (BSL.length c) return (ChanString "") {- | Split a list by a given character and select ranges of the resultant lists. > cutR [2..4] ' ' "foo bar baz quux foobar" -> "baz quux foobar" > cutR [1..1000] ' ' "foo bar baz quux foobar" -> "bar baz quux foobar" > cutR [-1000..1000] ' ' "foo bar baz quux foobar" -> "foo bar baz quux foobar" Note that too large and too small indices are essentially ignored. -} cutR :: [Integer] -> Char -> String -> String cutR nums delim z = drop 1 $ concat [delim:x | (x, y) <- zip string [0..], elem y nums] where string = split delim z {- | Takes a string and sends it on as standard output. The input to this function is never read. You can pass this thing a String, a ByteString, or even a Handle. See also 'echoBS'. -} echo :: Channelizable a => a -> Channel -> IO Channel echo inp _ = return . toChannel $ inp {- | Search for the regexp in the lines. Return those that match. -} egrep :: String -> [String] -> [String] egrep pat = filter (ismatch regex) where regex = mkRegex pat ismatch r inp = case matchRegex r inp of Nothing -> False Just _ -> True {- | Search for the regexp in the lines. Return those that do NOT match. -} egrepV :: String -> [String] -> [String] egrepV pat = filter (not . ismatch regex) where regex = mkRegex pat ismatch r inp = case matchRegex r inp of Nothing -> False Just _ -> True {- | Exits with the specified error code. 0 indicates no error. -} exit :: Int -> IO a exit code | code == 0 = exitWith ExitSuccess | otherwise = exitWith (ExitFailure code) {- | Takes a pattern. Returns a list of names that match that pattern. Handles: >~username at beginning of file to expand to user's home dir >? matches exactly one character >* matches zero or more characters >[list] matches any character in list >[!list] matches any character not in list The result of a tilde expansion on a nonexistant username is to do no tilde expansion. The tilde with no username equates to the current user. Non-tilde expansion is done by the MissingH module System.Path.Glob. -} glob :: FilePath -> IO [FilePath] glob inp@('~':remainder) = catch expanduser (\_ -> Glob.glob rest) where (username, rest) = span (/= '/') remainder #ifdef __HSH_POSIX__ expanduser = do lookupuser <- if username /= "" then return username else getEffectiveUserName ue <- getUserEntryForName lookupuser Glob.glob (homeDirectory ue ++ rest) #else expanduser = fail "non-posix; will be caught above" #endif glob x = Glob.glob x {- | Search for the string in the lines. Return those that match. Same as: > grep needle = filter (isInfixOf needle) -} grep :: String -> [String] -> [String] grep = filter . isInfixOf {- | Search for the string in the lines. Return those that do NOT match. -} grepV :: String -> [String] -> [String] grepV needle = filter (not . isInfixOf needle) -- | Join lines of a file joinLines :: [String] -> [String] joinLines = return . concat #ifdef __HSH_POSIX__ {- | Creates the given directory. A value of 0o755 for mode would be typical. An alias for System.Posix.Directory.createDirectory. The second argument will be ignored on non-POSIX systems. -} mkdir :: FilePath -> FileMode -> IO () mkdir = createDirectory #else mkdir :: FilePath -> a -> IO () mkdir fp _ = SD.createDirectory fp #endif {- | Number each line of a file -} numberLines :: [String] -> [String] numberLines = zipWith (printf "%3d %s") [(1::Int)..] {- | An alias for System.Directory.getCurrentDirectory. -} pwd :: IO FilePath pwd = getCurrentDirectory #ifdef __HSH_POSIX__ {- | Return the destination that the given symlink points to. An alias for System.Posix.Files.readSymbolicLink This function is only available on POSIX platforms. -} readlink :: FilePath -> IO FilePath readlink fp = do issym <- (getFileStatus fp >>= return . isSymbolicLink) if issym then readSymbolicLink fp else return fp {- | As 'readlink', but turns the result into an absolute path. This function is only available on POSIX platforms. -} readlinkabs :: FilePath -> IO FilePath readlinkabs inp = do issym <- (getFileStatus inp >>= return . isSymbolicLink) if issym then do rl <- readlink inp case absNormPath (dirname inp) rl of Nothing -> fail $ "Cannot make " ++ show rl ++ " absolute within " ++ show (dirname inp) Just x -> return x else abspath inp #endif {- | Reverse characters on each line (rev) -} rev, revW :: [String] -> [String] rev = map reverse {- | Reverse words on each line -} revW = map (unwords . reverse . words) {- | Reverse lines in a String (like Unix tac). Implemented as: > tac = reverse See 'uniq'. -} tac :: [String] -> [String] tac = reverse {- | Takes input, writes it to all the specified files, and passes it on. This function does /NOT/ buffer input. See also 'catFrom'. -} tee :: [FilePath] -> Channel -> IO Channel tee fplist inp = teeBSGeneric (\fp -> openFile fp WriteMode) fplist inp #ifdef __HSH_POSIX__ {- | FIFO-safe version of 'tee'. This call will BLOCK all threads on open until a reader connects. This function is only available on POSIX platforms. -} teeFIFO :: [FilePath] -> Channel -> IO Channel teeFIFO fplist inp = teeBSGeneric fifoOpen fplist inp #endif teeBSGeneric :: (FilePath -> IO Handle) -> [FilePath] -> Channel -> IO Channel teeBSGeneric openfunc fplist ichan = do handles <- mapM openfunc fplist inp <- chanAsBSL ichan resultChunks <- hProcChunks handles (BSL.toChunks inp) return (ChanBSL $ BSL.fromChunks resultChunks) where hProcChunks :: [Handle] -> [BS.ByteString] -> IO [BS.ByteString] hProcChunks handles chunks = unsafeInterleaveIO $ case chunks of [] -> do mapM_ hClose handles return [BS.empty] (x:xs) -> do mapM_ (\h -> BS.hPutStr h x) handles remainder <- hProcChunks handles xs return (x : remainder) {- | Translate a character x to y, like: >tr 'e' 'f' Or, in sed, >y// -} tr :: Char -> Char -> String -> String tr a b = map (\x -> if x == a then b else x) {- | Delete specified character in a string. -} trd :: Char -> String -> String trd = filter . (/=) {- | Remove duplicate lines from a file (like Unix uniq). Takes a String representing a file or output and plugs it through lines and then nub to uniqify on a line basis. -} uniq :: String -> String uniq = unlines . nub . lines {- | Double space a file; add an empty line between each line. -} space :: [String] -> [String] space = intersperse "" {- | Inverse of double 'space'; drop all empty lines. -} unspace :: [String] -> [String] unspace = filter (not . null) {- | Convert a string to all lower case -} lower :: String -> String lower = map toLower {- | Convert a string to all upper case -} upper :: String -> String upper = map toUpper {- | Count number of lines. Like wc -l -} wcL :: [String] -> [String] wcL inp = [show (genericLength inp :: Integer)] {- | Count number of words in a file (like wc -w) -} wcW :: [String] -> [String] wcW inp = [show ((genericLength $ words $ unlines inp) :: Integer)] {- Utility function. > split ' ' "foo bar baz" -> ["foo","bar","baz"] -} split :: Char -> String -> [String] split c s = case rest of [] -> [chunk] _:rst -> chunk : split c rst where (chunk, rest) = break (==c) s -- TODO: Perhaps simplify to make use of split splitpath :: String -> (String, String) splitpath "" = (".", ".") splitpath "/" = ("/", "/") splitpath p | last p == '/' = splitpath (init p) | not ('/' `elem` p) = (".", p) | head p == '/' && length (filter (== '/') p) == 1 = ("/", tail p) | otherwise = (\(base, dir) -> (reverse (tail dir), reverse base)) (break (== '/') (reverse p))