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|
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE CPP #-}
--------------------------------------------------------------------------------
-- | A module containing various file utility functions
module Hakyll.Core.Util.File
( makeDirectories
, getRecursiveContents
, removeDirectory
) where
--------------------------------------------------------------------------------
import Control.Monad (filterM, forM)
import System.Directory (createDirectoryIfMissing,
doesDirectoryExist, getDirectoryContents)
import System.FilePath (takeDirectory, (</>))
#ifndef mingw32_HOST_OS
import Control.Monad (when)
import System.Directory (removeDirectoryRecursive)
#else
import Control.Concurrent (threadDelay)
import Control.Exception (SomeException, catch)
import System.Directory (removePathForcibly)
#endif
--------------------------------------------------------------------------------
-- | Given a path to a file, try to make the path writable by making
-- all directories on the path.
makeDirectories :: FilePath -> IO ()
makeDirectories = createDirectoryIfMissing True . takeDirectory
--------------------------------------------------------------------------------
-- | Get all contents of a directory.
getRecursiveContents :: (FilePath -> IO Bool) -- ^ Ignore this file/directory
-> FilePath -- ^ Directory to search
-> IO [FilePath] -- ^ List of files found
getRecursiveContents ignore top = go ""
where
isProper x
| x `elem` [".", ".."] = return False
| otherwise = not <$> ignore x
go dir = do
dirExists <- doesDirectoryExist (top </> dir)
if not dirExists
then return []
else do
names <- filterM isProper =<< getDirectoryContents (top </> dir)
paths <- forM names $ \name -> do
let rel = dir </> name
isDirectory <- doesDirectoryExist (top </> rel)
if isDirectory
then go rel
else return [rel]
return $ concat paths
--------------------------------------------------------------------------------
removeDirectory :: FilePath -> IO ()
#ifndef mingw32_HOST_OS
removeDirectory fp = do
e <- doesDirectoryExist fp
when e $ removeDirectoryRecursive fp
#else
-- Deleting files on Windows is unreliable. If a file/directory is open by a program (e.g. antivirus),
-- then removing related directories *quickly* may fail with strange messages.
-- See here for discussions:
-- https://github.com/haskell/directory/issues/96
-- https://github.com/haskell/win32/pull/129
--
-- The hacky solution is to retry deleting directories a few times,
-- with a delay, on Windows only.
removeDirectory = retryWithDelay 10 . removePathForcibly
--------------------------------------------------------------------------------
-- | Retry an operation at most /n/ times (/n/ must be positive).
-- If the operation fails the /n/th time it will throw that final exception.
-- A delay of 100ms is introduced between every retry.
retryWithDelay :: Int -> IO a -> IO a
retryWithDelay i x
| i <= 0 = error "Hakyll.Core.Util.File.retry: retry count must be 1 or more"
| i == 1 = x
| otherwise = catch x $ \(_::SomeException) -> threadDelay 100 >> retryWithDelay (i-1) x
#endif
|
