filemanip/System/FilePath/Glob.hs
2010-03-05 21:19:53 +00:00

73 lines
2.5 KiB
Haskell

-- |
-- Module: System.FilePath.Glob
-- Copyright: Bryan O'Sullivan
-- License: BSD3
-- Maintainer: Bryan O'Sullivan <bos@serpentine.com>
-- Stability: unstable
-- Portability: everywhere
module System.FilePath.Glob (
namesMatching
) where
import Control.Monad (forM)
import System.FilePath.GlobPattern ((~~))
import System.Directory (doesDirectoryExist, doesFileExist,
getCurrentDirectory, getDirectoryContents)
import System.FilePath (dropTrailingPathSeparator, splitFileName, (</>))
import System.IO.Unsafe (unsafeInterleaveIO)
import System.FilePath.Error (handle)
-- | Return a list of names matching a glob pattern. The list is
-- generated lazily.
namesMatching :: String -> IO [FilePath]
namesMatching pat
| not (isPattern pat) = do
exists <- doesNameExist pat
return (if exists then [pat] else [])
| otherwise = do
case splitFileName pat of
("", baseName) -> do
curDir <- getCurrentDirectory
listMatches curDir baseName
(dirName, baseName) -> do
dirs <- if isPattern dirName
then namesMatching (dropTrailingPathSeparator dirName)
else return [dirName]
let listDir = if isPattern baseName
then listMatches
else listPlain
pathNames <- forM dirs $ \dir -> do
baseNames <- listDir dir baseName
return (map (dir </>) baseNames)
return (concat pathNames)
where isPattern = any (`elem` "[*?")
listMatches :: FilePath -> String -> IO [String]
listMatches dirName pat = do
dirName' <- if null dirName
then getCurrentDirectory
else return dirName
names <- unsafeInterleaveIO (handle (const (return [])) $
getDirectoryContents dirName')
let names' = if isHidden pat
then filter isHidden names
else filter (not . isHidden) names
return (filter (~~ pat) names')
where isHidden ('.':_) = True
isHidden _ = False
listPlain :: FilePath -> String -> IO [String]
listPlain dirName baseName = do
exists <- if null baseName
then doesDirectoryExist dirName
else doesNameExist (dirName </> baseName)
return (if exists then [baseName] else [])
doesNameExist :: FilePath -> IO Bool
doesNameExist name = do
fileExists <- doesFileExist name
if fileExists
then return True
else doesDirectoryExist name