Flippi-0.0.5: src/PageIO.hs

{-
Copyright (c) 2004, Philippa Jane Cowderoy
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-}

module PageIO (isPagename,
               getPageLastUpdated,
               writePage,
               getPage,
               getPagenames)
where

import System.Time
import System.Directory
import System.IO
import Monad

import DeWikify(pagenamePattern)
import Text.ParserCombinators.Parsec as Parsec

dataDirectory = "data"

pagenameToFilename pn = dataDirectory ++ "/" ++ pn                     

isPagename pn = case (parse (do {pagenamePattern; eof;}) "" pn) of
                 Left _ -> False
                 Right _ -> True

getPageLastUpdated :: String -> IO (Maybe ClockTime)
getPageLastUpdated p =   
  catch (do date <- getModificationTime (pagenameToFilename p)
            return (Just date)
        )
        (\_ -> return Nothing)

deCRLF s = case parse (many (Parsec.try (do string "\r\n"; return '\n')
                             <|> 
                             anyChar 
                            )
                      )
                      "" 
                      s of
            Right r -> r

writePage p text = do h <- openBinaryFile (pagenameToFilename p) WriteMode
                      hPutStr h (deCRLF text)
                      hClose h

getPage p env = do exists <- doesFileExist fn
                   if (exists) then
                    do xs <- readFile fn
                       case (deCRLF xs) of
                        [] -> return (Just [])
                        dxs -> return (last dxs `seq` Just dxs)
                    else return Nothing
              where fn = pagenameToFilename p

getPagenames = do dir <- getDirectoryContents dataDirectory                  
                  filterM con dir 
             where con fp = do c1 <- doesFileExist (pagenameToFilename fp)
                               c2 <- return (isPagename fp)
                               return (c1 && c2)