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{-# LANGUAGE GeneralizedNewtypeDeriving #-}
{-
Copyright (C) 2014 John MacFarlane <jgm@berkeley.edu>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
-}
{- |
Module : Text.Pandoc.MediaBag
Copyright : Copyright (C) 2014 John MacFarlane
License : GNU GPL, version 2 or above
Maintainer : John MacFarlane <jgm@berkeley.edu>
Stability : alpha
Portability : portable
Definition of a MediaBag object to hold binary resources, and an
interface for interacting with it.
-}
module Text.Pandoc.MediaBag (
MediaBag,
lookupMedia,
insertMedia,
mediaDirectory,
extractMediaBag
) where
import System.FilePath
import System.Directory (createDirectoryIfMissing)
import qualified Data.Map as M
import qualified Data.ByteString.Lazy as BL
import Data.Monoid (Monoid)
import Control.Monad (when, MonadPlus(..))
import Text.Pandoc.MIME (getMimeType)
import qualified Text.Pandoc.UTF8 as UTF8
import Data.Maybe (fromMaybe)
import System.IO (stderr)
-- | A container for a collection of binary resources, with names and
-- mime types. Note that a 'MediaBag' is a Monoid, so 'mempty'
-- can be used for an empty 'MediaBag', and '<>' can be used to append
-- two 'MediaBag's.
newtype MediaBag = MediaBag (M.Map String (String, BL.ByteString))
deriving (Monoid)
instance Show MediaBag where
show bag = "MediaBag " ++ show (mediaDirectory bag)
-- | Insert a media item into a 'MediaBag', replacing any existing
-- value with the same name.
insertMedia :: FilePath -- ^ relative path and canonical name of resource
-> Maybe String -- ^ mime type (Nothing = determine from extension)
-> BL.ByteString -- ^ contents of resource
-> MediaBag
-> MediaBag
insertMedia fp mbMime contents (MediaBag mediamap) =
MediaBag (M.insert fp (mime, contents) mediamap)
where mime = fromMaybe "application/octet-stream" (mbMime `mplus` fallback)
fallback = case takeExtension fp of
".gz" -> getMimeType $ dropExtension fp
_ -> getMimeType fp
-- | Lookup a media item in a 'MediaBag', returning mime type and contents.
lookupMedia :: FilePath
-> MediaBag
-> Maybe (String, BL.ByteString)
lookupMedia fp (MediaBag mediamap) = M.lookup fp mediamap
-- | Get a list of the file paths stored in a 'MediaBag', with
-- their corresponding mime types and the lengths in bytes of the contents.
mediaDirectory :: MediaBag -> [(String, String, Int)]
mediaDirectory (MediaBag mediamap) =
M.foldWithKey (\fp (mime,contents) ->
((fp, mime, fromIntegral $ BL.length contents):)) [] mediamap
-- | Extract contents of MediaBag to a given directory. Print informational
-- messages if 'verbose' is true.
extractMediaBag :: Bool
-> FilePath
-> MediaBag
-> IO ()
extractMediaBag verbose dir (MediaBag mediamap) = do
sequence_ $ M.foldWithKey
(\fp (_ ,contents) ->
((writeMedia verbose dir (fp, contents)):)) [] mediamap
writeMedia :: Bool -> FilePath -> (FilePath, BL.ByteString) -> IO ()
writeMedia verbose dir (subpath, bs) = do
-- we join and split to convert a/b/c to a\b\c on Windows;
-- in zip containers all paths use /
let fullpath = dir </> joinPath (splitPath subpath)
createDirectoryIfMissing True $ takeDirectory fullpath
when verbose $ UTF8.hPutStrLn stderr $ "pandoc: extracting " ++ fullpath
BL.writeFile fullpath bs
|
