diohsc-0.1.1: Mundanities.hs

-- This file is part of Diohsc
-- Copyright (C) 2020 Martin Bays <mbays@sdf.org>
--
-- This program is free software: you can redistribute it and/or modify
-- it under the terms of version 3 of the GNU General Public License as
-- published by the Free Software Foundation, or any later version.
--
-- You should have received a copy of the GNU General Public License
-- along with this program.  If not, see http://www.gnu.org/licenses/.

{-# LANGUAGE Safe #-}

module Mundanities where

import Control.Applicative (Alternative, empty)
import Control.Monad.Catch (MonadMask, handle)
import System.Directory
import System.FilePath
import Control.Monad.IO.Class (MonadIO, liftIO)

import qualified Data.ByteString as BS
import qualified Data.ByteString.Lazy as BL
import qualified Data.Text.Lazy as T
import qualified Data.Text.Lazy.Encoding as T
import qualified Data.Text as TS
import qualified Data.Text.IO as TS

mkdirhierto :: FilePath -> IO ()
mkdirhierto = mkdirhier . takeDirectory
mkdirhier :: FilePath -> IO ()
mkdirhier = createDirectoryIfMissing True

-- |returns true iff path is contained within the directory dir
isSubPath :: FilePath -> FilePath -> IO Bool
isSubPath dir path = isRelative . makeRelative dir <$> canonicalizePath path

ignoreIOErr :: (MonadIO m, MonadMask m, Monoid a) => m a -> m a
ignoreIOErr = handle ((\_ -> return mempty) :: (Monad m, Monoid a) => IOError -> m a)

warnIOErr :: (MonadIO m, MonadMask m, Monoid a) => m a -> m a
warnIOErr = handle ((\e -> liftIO (print e) >> return mempty) :: (MonadIO m, Monoid a) => IOError -> m a)

ignoreIOErrAlt :: (MonadIO m, MonadMask m, Alternative f) => m (f a) -> m (f a)
ignoreIOErrAlt = handle ((\_ -> return empty) :: (Monad m, Alternative f) => IOError -> m (f a))

warnIOErrAlt :: (MonadIO m, MonadMask m, Alternative f) => m (f a) -> m (f a)
warnIOErrAlt = handle ((\e -> liftIO (print e) >> return empty) :: (MonadIO m, Alternative f) => IOError -> m (f a))

readFileLines :: FilePath -> IO [T.Text]
readFileLines path = ignoreIOErr $
    map T.strip . T.lines . T.decodeUtf8 . BL.fromStrict <$> BS.readFile path

-- delete all but last n lines of file
truncateToEnd :: Int -> FilePath -> IO ()
truncateToEnd n path =
    TS.unlines . dropAllBut n . TS.lines <$> TS.readFile path >>= TS.writeFile path
    where dropAllBut m as = drop (length as - m) as