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|
{-# LANGUAGE CPP #-}
{-# LANGUAGE DeriveDataTypeable #-}
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
{- |
Module : Text.Pandoc.MediaBag
Copyright : Copyright (C) 2014-2015, 2017–2020 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,
deleteMedia,
lookupMedia,
insertMedia,
mediaDirectory,
mediaItems
) where
import qualified Data.ByteString.Lazy as BL
import Data.Data (Data)
import qualified Data.Map as M
import Data.Maybe (fromMaybe)
import Data.Typeable (Typeable)
import System.FilePath
import qualified System.FilePath.Posix as Posix
import Text.Pandoc.MIME (MimeType, getMimeTypeDef)
-- | 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 [FilePath] (MimeType, BL.ByteString))
deriving (Semigroup, Monoid, Data, Typeable)
instance Show MediaBag where
show bag = "MediaBag " ++ show (mediaDirectory bag)
-- | Delete a media item from a 'MediaBag', or do nothing if no item corresponds
-- to the given path.
deleteMedia :: FilePath -- ^ relative path and canonical name of resource
-> MediaBag
-> MediaBag
deleteMedia fp (MediaBag mediamap) =
MediaBag $ M.delete (splitDirectories fp) mediamap
-- | 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 MimeType -- ^ mime type (Nothing = determine from extension)
-> BL.ByteString -- ^ contents of resource
-> MediaBag
-> MediaBag
insertMedia fp mbMime contents (MediaBag mediamap) =
MediaBag (M.insert (splitDirectories fp) (mime, contents) mediamap)
where mime = fromMaybe fallback mbMime
fallback = case takeExtension fp of
".gz" -> getMimeTypeDef $ dropExtension fp
_ -> getMimeTypeDef fp
-- | Lookup a media item in a 'MediaBag', returning mime type and contents.
lookupMedia :: FilePath
-> MediaBag
-> Maybe (MimeType, BL.ByteString)
lookupMedia fp (MediaBag mediamap) = M.lookup (splitDirectories 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 -> [(FilePath, MimeType, Int)]
mediaDirectory (MediaBag mediamap) =
M.foldrWithKey (\fp (mime,contents) ->
((Posix.joinPath fp, mime, fromIntegral $ BL.length contents):)) [] mediamap
mediaItems :: MediaBag -> [(FilePath, MimeType, BL.ByteString)]
mediaItems (MediaBag mediamap) =
M.foldrWithKey (\fp (mime,contents) ->
((Posix.joinPath fp, mime, contents):)) [] mediamap
|
